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Abundance of Arbuscular Mycorhizzal Fungi with Deforestation and Regeneration, Jacob O鈥機onnor

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Dimensions of Disaster During Hurricane Katrina: Landscapes, Levees, and the Least Fortunate, Sarah McKinnell听

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Abstract:

听听听听听听听听听听听 In 2005 Hurricane Katrina made landfall in Southeastern Louisiana as a powerful Category Three hurricane. The hurricane protection systems in place for the city of New Orleans and surrounding parishes were overwhelmed sending billions of gallons of water into local communities. This atypical flood volume inundated 80% of New Orleans, impeding rescue efforts and devastating infrastructure and emergency resources. Over 1,500 lives were lost and an estimated 125 billion US dollars were spent on emergency response, recovery, and reconstruction. Hurricane Katrina is the worst disaster in the United States in over a century.

听听听听听听听听听听听 This paper analyzes why Hurricane Katrina was such a catastrophe. Three major reasons for the disaster are identified: construction of piecemeal levee systems, wetland loss, and social vulnerabilities. Throughout the history of southeastern Louisiana鈥檚 settlement, the natural hydrography was manipulated in order to protect life and property from flooding; a fragmented levee system was constructed based on under estimated storm risk resulting in the hurricane protection system that failed during Hurricane Katrina. Similarly, increased residential development, canal building, and natural land subsidence processes have degraded natural wetlands which function as protective barriers from storm surges. The population of New Orleans exhibited high social vulnerabilities, as many Katrina victims lacked the tools, knowledge, and capabilities necessary to evacuate in a timely manner or to exercise other self-protective measures.

听听听听听听听听听听听 These three elements鈥攆ragmented levee systems, wetland degradation, and high social vulnerabilities鈥攅xacerbate the level of vulnerability of property and people along the Gulf Coast. In order to reduce the vulnerability and the probability of a similar catastrophic event occurring, an analysis of Hurricane Katrina can be utilized to improve future mitigation planning. Better mitigation could yield improvements in levee quality; areas of dramatic wetland decline can be monitored and perhaps protected from future development, and heavily populated areas with high social vulnerabilities can be recognized and considered priority zones for mitigation plans.

Accronyms Commonly Used:

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B-LLP听听听听听听听听听听听听 Barrier-Low-Level Hurricane Protection Plan

CWPPRA听听听听听听听听听听听听听听听听听听 Coastal Wetlands Planning, Protection, and Restoration Act Managing Agency

EIS听听听听听听听听听听听听听听听听听 Environmental Impact Statements

FEMA听听听听听听听听听听听听听听听听听听听听听听听 Federal Emergency Management Agency

HLP听听听听听听听听听听听听听听听 High-Level Plan

IHNC听听听听听听听听听听听听听 Inner Harbor Navigation Canal

LPHPP听听听听听听听听听听听听听听听听听听听听听听听 Lake Pontchartrain Hurricane Protection Plan

MRC听听听听听听听听听听听听听听 Mississippi River Commission

MRGO听听听听听听听听听听听听听听听听听听听听听听 Mississippi River Gulf Outlet

NASA听听听听听听听听听听听听 National Aeronautics and Space Administration

NHC听听听听听听听听听听听听听听 National Hurricane Center

NOAA听听听听听听听听听听听听听听听听听听听听听听听 National Oceanic and Atmospheric Administration

NWS听听听听听听听听听听听听听听 National Weather Service

SPH听听听听听听听听听听听听听听听听 Standard Project Hurricane

USACE听听听听听听听听听听听听听听听听听听听听听听 United States Army Corps of Engineers

USGS听听听听听听听听听听听听听 United States Geological Survey

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Table of Contents:

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Introduction听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听

听听听听听听听听听听听 The Storm听听听听听听听听听听听听听听听听听听 听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听 5

Background

听听听听听听听听听听听 The Geography of New Orleans听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听 听听听听听听听听听听听 10

The Construction of the Pre-Katrina Landscape听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听The Crescent City: 1733 to 1927听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听 13

听听听听听听听听听听听 Flood Management: 1927 to 1965听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听 16

听听听听听听听听听听听 Reassessment and Repeated Mistakes: 1965 to 2005听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听 21

Wetland Decline听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听25

Social听Vulnerabilities听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听30

Future Mitigation and Conclusions听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听34

Afterword听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听38

References听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听40

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Introduction 鈥� The Storm

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Figure 1: Hurricane Katrina making landfall, August 29, 2005. NOAA Katrina Homepage.

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听听听听听听听听听听听 On August 29, 2005 Hurricane Katrina battered the low-lying lands of the central Gulf states (Johnson 2006). The eyewall of the Category Three storm crossed over southern Plaquemines Parish, Louisiana with maximum wind speeds of 125 miles per hour (NOAA 2007). The devastation was widespread across the Gulf Coast as Katrina鈥檚 damaging winds and storm surge stretched over 230 miles outward from the center (Graumann et. al 2006). The city of New Orleans was pummelled by heavy rainfall, 100+ mile per hour winds, and in some areas a storm surge of up to 28 feet (NOAA 2007). Eighty percent of the metropolis of New Orleans was inudated by flood waters; some areas such as the Lower Ninth Ward and Lakeview were under up to twenty feet of water (Graumann et. al 2006). Much of the infrastructure in New Orleans, such as transportation networks, schools, government buildings, and emergency response services were damaged leaving neighborhoods unrecognizeable, highways impassible, and electricity knocked out for over 1.7 million people (NOAA 2007). The storm overwhelmed protective seawalls and the intricate levee system in the region forcing hundreds of thousands of residents to evacuate or endure the dooms-day-like conditions. Hurricane Katrina claimed between 1500 and 1800 lives, making it the second most deadly hurricane event in U.S. history, second only to the Galveston Island, Texas hurricane of 1900 (NOAA 2007).

听听听听听听听听听听听 In the weeks after the storm, Americans and the global community witnessed surreal imagery and tragic accounts of death and survival. The United States, one of the most developed and prosperous nations in the world, had endured a large-scale natural disaster. Looting and violence broke out, surviviors were forced to wait on rooftops and in shelters for days without access to potable water and food, and corpses floated through toxic waters (Johnson 2006). In New Orleans and surrounding parishes the polluted mire remained stagnant for up to 43 days after Katrina鈥檚 initial landfall (Johnson 2006).

听听听听听听听听听听听 Two flood maps (Figure 2 and 3) demonstrate the magnitude of flood waters in New Orleans Parish and the length of time it took for the waters to recede or be pumped out (NOAA 2006). Figure 2 shows the depth of flooding two days after the storm on August 31, 2005. Much of the city was flooded by four to eight feet of water, with some areas such as New Orleans East inundated by up to fifteen feet of water. Figure 3 shows flood waters still present on September 20, 2005. It took until October 11, 2005 for the floodwaters to be completely drained from the city鈥檚 limits (Johnson 2006). Figure 4 and Figure 5 show before and after satellite imagery of the lower Mississippi River Delta. Flooding was extreme throughout Southeastern Louisiana in addition to the New Orleans metropolitan area.

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Figure 2: New Orleans Flood Map 鈥� August 31, 2005.听Source:听NOAA Flood Maps 2006.

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Figure 3: New Orleans Flood Map 鈥� September 20, 2005.听Source:听NOAA Flood Maps. 2006.

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Figure 4: MS River Delta flooded from Hurricane Katrina on September 4, 2005.听The coloring has been amplified to make the landscape changes more apparent.听Source:听NASA听Earth Observatory Terra-MODIS Satellite Imagery.2005. 听 听 听 听 听 听 Figure 5: MS River Delta unflooded on August 9, 2005.听The coloring has been amplified to make the landscape changes more apparent. Source: NASA听Earth Observatory Terra-MODIS Satellite Imagery.听2005. 听 听 听

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听听听听听听听听听听听 Hurricane Katrina had surprisingly large impacts; however, Hurricane Katrina was not the strongest storm in history to make landfall on the Gulf Coast. Hurricane Camille struck the same region of the central Gulf States in 1969 as a Category Five storm according to the Saffir-Simpson Hurricane Scale (Table 1). This scale is based upon a hurricane鈥檚 maximum wind speed: categories three through five are considered major hurricanes, with categories four and five resulting in catastrophic damages and losses (Graumann et. al 2006). At one point during its formation Hurricane Katrina was considered a Category Five storm, but the winds died down considerably before making landfall in Louisiana on August 29 (Roth 2010). In the same 2005 hurricane season, Hurricanes Rita and Wilma also reached Category Five status and made landfall as intense Category Three hurricanes (Roth 2010). Yet, Camille, Rita, and Wilma did not produce the extensive and widespread flooding and damage witnessed during Hurricane Katrina.

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Table 1: Categorization of hurricanes鈥� strength based upon wind speed. Source: Graumann et al. 2006.

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The aftermath of Hurricane Katrina reveals continued vulnerability to natural disasters even for a highly developed nation and a region that has experienced many hurricane disasters. The storm exposed the shortcomings of engineering as well as emergency response. In order to reduce the likelihood of future hurricane losses in the Gulf states and other exposed coastal geographies, an analysis of the impact of Hurricane Katrina, with attention to the weaknesses in adaptation that it revealed, can provide lessons and insights into the relationships between humans and the environment that make the region vulnerable. This paper proposes three main reasons for the extent of destruction during Hurricane Katrina: piecemeal levee and seawall construction, wetland and natural buffer zone decline exacerbated by development of unsuitable lands and natural subsidence processes, and high levels of social inequalities that resulted in an extremely vulnerable population of non-evacuees. Analysis of these three key components could yield insight to improve future mitigation, prevention, and planning systems.

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Background 鈥� The Geography of New Orleans

听听听听听听听听听听听 The Mississippi River Delta is a low-lying geographic region characterized by wetlands, estuaries, and the meandering Mississippi River (CWPPRA 2011). The River Delta is located between Mississippi and Lousiana where the Mississippi River makes its way to the Gulf of Mexico (CWPPRA 2011). The river dominates the landscape of southeastern Louisiana and southwestern Mississippi, creating an alluvial valley with routine flooding (Miller and Rivera 2008). Geologic sediment samples indicate that the river has changed its route to the Gulf of Mexico through time depending on land elevation, sediment composition, and sea level (Van Heerden and Bryan 2006); this indicates a transient state for the entire delta-plain. Van Heerden and Bryan refer to the Louisiana coastal zone as a "living landscape", which exhibits a dynamic balance between sediment deposition and recession (2006, p 153). Before early settlement and land development, cypress swamps and marshes extended further south of Lake Pontchartrain than seen today (Kindinger 2001). Similarly, the barrier islands in the Gulf of Mexico were more prominent, acting as a natural line of defense against hurricane storm surges (Kindinger 2001). Today, the living landscape of Louisiana exists as an amalgamation of concrete, swamp, river, and infrastructure with high levels of wetland decline. (NASA 2005).

听听听听听听听听听听听 New Orleans is referred to as the 鈥淐rescent City鈥� due to its crescent-moon-like curvature along the banks of the Mississippi River (Miller and Rivera 2008). To the north of New Orleans, a levee system outlines the coast of Lake Pontchartrain, a large brackish water estuary that provides habitat for flora and fauna as well as recreational opportunities for surrounding populations (Moreau 2006). To the east, Orleans Parish is bordered by the Inner Harbor Navigation Canal (IHNC) otherwise known as the Industrial Canal (Moreau 2006); beyond the IHNC is New Orleans East, a newer residential section bordered by Lake Borgne, the gateway to the Gulf of Mexico (Moreau 2006). New Orleans and neighboring parishes are bordered to the south by the Mississippi River as it winds its way into the Gulf of Mexico (Moreau 2006); to the west of Orleans Parish lies the 17th听St. Canal and Jefferson Parish (Moreau 2006).

听听听听听听听听听听听 The major water features of New Orleans along with notable neighborhoods and roadways are visible in Figure 6. Figure 6 shows that New Orleans is bordered by water on all sides; to the north there is Lake Pontchartrain, to the east the IHNC which connects to the southern border of the Mississippi River, and then the 17th St. Canal on the western border which reconnects with Lake Pontchartrain. In addition to being surrounded by water, the city basin is located mostly below sea level with some areas up to eight feet below the sea surface (Figure 7). The low elevation of the city is problematic as the entire region is susceptible to flooding and storm surges. Figure 7 (below) reveals the predicament of New Orleans鈥� bowl-like geography. In flooding situations, the surrounding water features spill into the areas lying below sea-level, inundating most of the city.

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Figure 6: A generalized map of prominent New Orleans features and the surrounding water systems.听Source: Rogers, J.D.听2008.

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Figure 7: Elevation of New Orleans and surrounding parishes. Scale: 1: 700,000.听Source:听Kosovich, John J. 2008.

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The Construction of the Pre-Katrina Landscape 鈥� The Crescent City: 1733 to 1927

听听听听听听听听听听听 The night before Hurricane Katrina struck the central Gulf region, the landscape existed as a product of hundreds of years of human alteration. The history of New Orleans is marked by frequent hurricanes, storm surges, and river flooding events; these events were perceived as manageable by early white settlers of the Mississippi River Delta (Miller and Rivera 2008). Beginning with the founding of New Orleans in 1733 by French colonists a precept was spread: the New Orleans region was a gateway that must be tamed in order to establish a pivotol port that would bring prosperity to the land (Miller and Rivera 2008). The mouth of the Mississippi was seen as a tempestuous entity and simultaneously as a financial wellspring. Miller and Rivera describe this desire to conquer the 鈥渟hortcomings of the New Orleans topography鈥� as 鈥渟urprising evidence of what men will endure鈥� (2008, p 26). The annual drowning of the land and non-routine flooding from frequent storms would prove to be harder to manage than originally believed, and they continue to be a 鈥渟hortcoming鈥� of the Mississippi River Delta today.

听听听听听听听听听听听 Initially, the Crescent City was developed to have a network of roadways known as the 鈥渟ixty-six block grid鈥� (Miller and Rivera 2008). The sixty-six block grid was built on the highest ground between the Mississippi River and Lake Pontchartrain (Miller and Rivera 2008). This business epicenter did not provide enough housing for early settlers, however, which led to the establishment of 鈥渇aubourgs鈥�, or suburbs (Miller and Rivera 2008). The faubourgs were built to the north and west of the sixty-six block grid in low-lying, swampy areas. The faubourgs were subject to overspill from the neighboring Lake Pontchartrain during storm events, in addition to seasonal flooding from the Mississippi River (Miller and Rivera 2008). In order to cope with the annual saturation of the land, local farmers and land owners buffed up the landscape鈥檚 natural levees (Miller and Rivera 2008). There was neither congruency nor communication between levee systems and their constructors, resulting in a piecemeal and permeable 鈥渟ystem鈥�; this in turn caused continued flooding of the terrain (Miller and Rivera 2008).

听听听听听听听听听听听 Major levee failures occurred during the city鈥檚 first century as a port. Notably, on May 5, 1816 and May 4, 1849, the Mississippi River breached the levees flooding St. Charles Place and the French Quarter (the sixty-six block grid) with up to eight feet of water (Miller and Rivera 2008). In addition, major hurricanes afflicted the region. The 鈥淕reat Louisiana Hurricane鈥� on August 9, 1812 sent fifteen feet of water into St. Bernards Parish just across the river from New Orleans proper; the 鈥淕reat Barbados Hurricane鈥� of 1831 swelled the levels of Lake Pontchartrain, creating a three foot storm surge that flooded New Orleans鈥� suburbs (Miller and Rivera 2008). During this era, the highest levee in New Orleans was a natural levee composed of silt deposits (Van Heerden and Bryan 2006). This levee stood ten feet above the city floor, which rested nearly eight feet below sea level, indicating only a two foot wall above sea level of protection from storm surges and annual flooding (Van Heerden and Bryan 2006).

听听听听听听听听听听听 The mid-to-late-nineteenth century again saw major flooding of the Mississippi River. Local governments were in charge of the levees and floodwalls up until the 1860s, when the U.S. 听federal government decided to provide financial assistance in order to establish a 鈥渃ontinuous levee system鈥� (Miller and Rivera 2008, p 29). This continuous system was proposed as a method to resolve听seasonal听flooding in the New Orleans area and to benefit navigation networks, not to provide flood protection from hurricanes (Miller and Rivera 2008). Thus, the levee construction was organized around containing the swelling of the Mississippi River, not providing protection along the Gulf of Mexico or from Lake Pontchartrain.

听听听听听听听听听听听 In need of an overarching organization to manage levee building, in 1879 the U.S. government established the Mississippi River Commission (MRC) headed by the United States Army Corps of Engineers (USACE); the MRC was designed to be in charge of levee and canal construction and development for the entire Mississippi River Delta (Miller and Rivera 2008). The MRC initially set out constructing levees to support navigation and channeling in the Mississippi River Delta, but after widespread severe flooding in 1927, the U.S. government mandated that levee building and canal construction provide flood and storm surge protection to prevent life and property losses within the delta region (Van Heerden and Bryan 2006).

听听听听听听听听听听听 The federal government shifted the focus of levee construction towards flood management due to the increasing population in New Orleans. From 1900 to 1950 the population doubled in size (USGS Coastal and Marine Geology Program 2010). Table 2 demonstrates the dramatic increase in New Orleans鈥� population from 1900 to 1950 (USGS Coastal and Marine Geology Program 2010). This escalation prompted new development in areas further away from the highest ground at the city center (Moreau 2006).听 These suburbs were built on below-sea-level, wetland terrain, creating communities that were vulnerable to flooding (Van Heerden and Bryan 2006). This new development also necessitated new levees.

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Table 2:听Population of New Orleans Chart. Source: USGS Coastal and Marine Geology Program. 2010.

听听听听听听听听听听听 From its early settlement, New Orleans was a region marked by fluxing and tempestuous

water features. The shortcomings of the regional

topography, however, were considered to be

problematic but controllable. Despite repeated flooding events, development increased and the population expanded. In order to improve navigation canals and handle seasonal flooding for the growing city, the MRC was created to oversee levee construction for the lower-river delta. In 1927, nearly two centuries after New Orleans was founded, the purpose of levee construction was shifted towards hurricane protection. The early history of New Orleans suggests that the region was quickly over-populated and under-protected, leaving the dilemma of how to protect lives and property to future generations.

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The Construction of the Pre-Katrina Landscape 鈥� Flood Management: 1927 to 1965

听听听听听听听听听听听 From 1927 to 1960 the USACE constructed the levee and canal system that remains the heart of the modern levee system in place in New Orleans (Van Heerden and Bryan, 2006). Floodwalls were built in front of earthen levees to bar off Lake Pontchartrain, the Jefferson Parish levee and the INHC were constructed, and the Mississippi River鈥檚 seasonal inundation of New Orleans was mitigated by the construction of the Bonnet Carre Spillway, just 23 miles north of New Orleans (Moreau 2006; NOAA 2011). The Bonnet Carre Spillway is a floodgate-controlled outlet that can redirect up to 250,000 cubic feet of water per second into Lake Pontchartrain (NOAA 2011). The Spillway is currently still in use; its construction prevented what geologists predict would have been an eventual merging of the Mississippi River and the Atchafalaya River (Van Heerden and Bryan 2006). By redirecting seasonal floodwaters, the Bonnet Carre Spillway has allowed the Mississippi River to maintain its current flow path instead of fluxing in the direction of its overflowing waters (NOAA 2011).

听听听听听听听听听听听 With seasonal flooding 鈥渦nder control鈥�, the U.S. federal government sought to expand protection for storms. In 1965, Congress instructed the USACE to devise a hurricane and severe tropical storm protection plan that could harbor New Orleans from even the most severe of storms (Moreau 2006). The USACE proposed the Lake Pontchartrain Hurricane Protection Plan (LPHPPP) that was designed to protect the area from the Standard Project Hurricane (SPH) (Moreau 2006). The Standard Project Hurricane was described by the USACE as 鈥渢he one that may be expected from the most severe combination of meteorological conditions that are reasonably characteristic of the region鈥� (Moreau 2006, p 27). The USACE estimated the maximum winds of the SPH to be 100 miles per hour with a return period of two-hundred years, or an annual probability of .5% (Moreau, 2006, p 27). A return period refers to what Smith and Petley define as 鈥渢he time that, on average, elapses between two events that equal, or exceed, a given magnitude鈥� (2009, p. 55). In other words, the SPH, a Category Three hurricane on the Saffir-Simpson Scale, was expected to occur on average every two-hundred years.

听听听听听听听听听听听 The LPHPP contained two potential protection designs: the Barrier-Low-Level Hurricane Protection Plan (B-LLP) and the High-Level Plan (HLP) (Moreau 2006). The B-LLP involved dredging wetlands for barrier enhancement of the current levee system (Moreau 2006). The HLP was more costly and called for floodgates to be constructed at major canal entrances, functioning as a blockade to storm surges (Moreau 2006). The floodgates could be closed before storms made landfall, preventing storm surges from rushing up canals and flooding the local neighborhoods (Moreau 2006). The Mississippi River Commission, which was now comprised of local levee bureaus, federal emergency management groups, and the USACE, chose to implement the B-LLP; however, both the B-LLP and the HLP were modelled after an undercalculated SPH (Richardson et al 2008).

听听听听听听听听听听听 Recent calculations performed by researchers at the National Hurricane Center and the National Weather Service (NWS) indicate that rather than a two-hundred year return period of a Category Three hurricane making landfall in southeastern Louisiana, there is a twenty year return period (Blake et. al 2011). Figure 8 represents return periods of a Category Three strength storm or higher making landfall for the eastern coastal U.S. counties. Louisiana has one of the shortest return intervals, along with the southern coast of Florida and the coast of North Carolina, indicating a substantial under estimation by the USACE.

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Figure 8: Estimated return periods for U.S. counties of a Category Three Hurricane or stronger making landfall. Blake et al. 2011.

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听听听听听听听听听听听 Table 3, created by David Roth in conjunction with the NWS and NOAA, displays the number of hurricanes and tropical storms to strike the coast of Louisiana from 1850 through 2000 (2010, p 7). Striking refers to the eye-wall or a portion of the eye-wall passing over part of the state of Louisiana. Fifty-four hurricanes were reported to have made landfall in a one-hundred and fifty year time period; this indicates that a hurricane should be expected to make landfall in Louisiana on average every 2.8 years (Roth 2010). In the 1960s alone, four hurricanes that struck Louisiana, three of which matched or surpassed Category Three intensity (Roth 2010). This again would indicate a major underestimation of the SPH鈥檚 return period.

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Table 3: Table displaying Hurricane or Tropical Storm strikes for the entire state of Louisiana. Source:听Roth, David. 2010. 听

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听听听听听听听听听听听 Besides a miscalculated return period, a case can be made that the USACE underestimated the intensity of the SPH; hurricanes of greater magnitude have directly and indirectly struck the Mississippi River Delta (Blake et al 2011). In 1969, just four years after the LPHPP was proposed, Hurricane Camille made landfall on the border of southeastern Louisiana and southwestern Mississippi as 鈥渢he most intense hurricane known to ever make landfall in the United States鈥� based upon wind speed and storm pressure (Roth 2010, p 42). Camille hit the coastline as a powerful Category Five hurricane on the Saffir-Simpson Scale (Roth 2010). Also, four Category Four hurricanes have struck the Louisiana coast from 1850 to 2004 (Moreau 2006). Two out of these four hurricanes to affect Louisiana occurred within the decade prior to the USACE鈥檚 LPHPP proposals. Although they made landfall in southwestern Louisiana and eastern Texas, Hurricane Audrey of 1957 and Hurricane Carla of 1961 were both stronger hurricanes than the SPH, and both created storm surges in the Mississippi River Delta that led to flooding in the New Orleans area (Roth 2010). The same year that the LPHPP was produced, Hurricane Betsy, a strong Category Three storm, struck just east of New Orleans (Roth, 2010). Betsy created a storm surge of over ten feet along the Mississippi River, sending nine feet of water into New Orleans East and Chalmette, inundating these regions for days (Roth 2010). 听

听听听听听听听听听听听 It is important to note the underrated SPH, because it justified the piecemeal levee system. If the SPH had been made equivalent to a Category Five hurricane, thus necessitating a superior hurricane protection plan, the fragmented construction and restoration produced by the LPHPP would not have been acceptable. However, the SPH was used as the framework for the New Orleans hurricane protection system for the next fifty years, and the lower sense of risk may have contributed to the catastrophe produced by Hurricane Katrina (Moreau 2006).

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The Construction of the Pre-Katrina Landscape 鈥� Reassessment and Repeated Mistakes: 1965 to 2005

听听听听听听听听听听听 The LPHPP construction, based upon the Barrier-Low-Level Protection Plan, did not commence until the late 1970s (Rogers 2008). When construction finally did start, it was carried out in a piecemeal fashion (Rogers 2008; ASCE 2007). Concrete was added to the French Quarter levee, levees at the east end of Plaquemines Parish were raised and fortified, and steel-sheet pilings were used to strengthen the IHNC (Van Heerden and Bryan 2006). These improvements benefitted specific areas of New Orleans, but the USACE neglected smaller communal levees in order to revamp the larger ones first (Rogers 2008). Thus, the smaller, local levees were reinforced to the USACE鈥檚 height standards by local levee boards, not the Army Corps of Engineers (Rogers 2008; ASCE 2007). While built up to USACE height standards, the local levee boards neglected to enlarge the levees鈥� bases, adding weight to a weakening base (Rogers 2008; ASCE 2007). Notably, the local levee boards made reinforcements along the 17th St. Canal levee and the London Avenue Canal levee, two levees that were breached by storm surges from Lake Pontchartrain during Hurricane Katrina (ASCE 2007).

听听听听听听听听听听听 By 1982, about 50% of the hurricane protection system was completed (Van Heerden and Bryan 2006). The slow rate of construction was largely due to federal and state funding constraints and new legislation passed by Congress, such as the Environmental Policy Act and the Clean Water Act, that required Environmental Impact Statements (EIS) (Moreau 2006). The EIS that the USACE drafted resulted in a forced shut down of barrier enhancement projects, because much of the B-LLP called for dredging and wetland removal in order to maintain levees and support canals, measures that did not meet the terms of environmental legislation (Moreau 2006). Furthermore, while complying with federal requirements, the USACE also had to work with local levee boards within the Mississippi River Commission (Rogers 2008). Most local levee bureaus supported less costly improvement plans in order to save taxpayer dollars (Rogers 2008). Alternative plans, such as the grandious HLP, would have added an unsightly 300 meter-wide embankment on the shores of Lake Pontchartrain, along with the massive floodgates displacing some homes along the coast (Rogers 2008); local officials and communities would not agree to such disruptions (Rogers 2008).听

听听听听听听听听听听听 In response to the slow onset of construction, the U.S. government instructed the USACE to reassess the 1965 LPHPP (Moreau 2006). The reevaluation began in 1984, upon which the USACE noted that the protection in place at the time was incomplete and not adequate enough to protect against the SPH (Richardson et. al 2008). In addition, levees and floodwalls in certain areas were found to be lower than their specified height and lacking uniform construction materials (Richardson et al 2008). This evaluation prompted two new plans for hurricane protection in the region: the Parallel Protection Plan and the Frontal Protection Plan (Moreau 2006). The USACE endorsed the Frontal Protection Plan which would build floodgates and high-functioning pumps at all major canal entrances and create a massive floodgate at the entrance to Lake Pontchartrain (Van Heerden and Bryan 2006); this plan would prevent storm surges from being able to enter the city through the canals and Lake Pontchartrain, effectively eliminating a significant portion of flooding in New Orleans (Moreau 2006). The local levee boards, however, supported the Parallel Protection Plan, which yet again called only for elevating the floodwalls and levee systems around the canals and included some barrier enhancement along the Pontchartrain lakefront (Moreau 2006); this further exacerbated the fragmented network of levees, because reinforcements were not uniform across the levee system (ASCE 2007).

听听听听听听听听听听听 Federal and state funding was allocated for the Parallel Protection Plan (Moreau 2006). Piecemeal construction ensued in which different materials were used to attach sections of one type of levee system to another (ASCE 2007). Figure 9 depicts levees at the 17th St. Canal and the London Avenue Canals in which the USACE connected concrete reinforcements with steel-sheet piling reinforcements (ASCE 2007, p. 64). Nearly all areas where this sort of bridging between two different levee styles occurred failed during Hurricane Katrina (ASCE 2007). Of the 350 miles of levees and floodwalls, 169 miles were damaged during the storm, and roughly 50 locations were either breached or overtopped by the storm surge (ASCE 2007).

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Figure 9: Levees demonstrating use of different building materials; these levees failed during Katrina. Source: ASCE.听2007. 听

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听听听听听听听听听听听 Additionally, levee and floodwall elevations varied throughout the network (ASCE 2007). While the Army Corps of Engineers mandated specific height requirements, these requirements differed depending on the materials used in levee section (ASCE 2007). For example, the type of floodwall known as the 鈥淚-Wall鈥� called for an earthen levee to support its frame higher than a regular earthen barrier (ASCE 2007). When these two sections were connected, the I-Wall levees stood significantly higher than the earthen levees. Figure 10 reveals a portion of the 17th St. Canal levee in which this scenario occurred. The I-Wall levee was connected to an earthen barrier, the barrier was lower in elevation, and the lower barrier was overtopped by the powerful storm surge (ASCE 2007).

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Figure 10: 17th St. Canal 鈥� Different elevations of levees along the same canal resulted in overtopping of the lower sections during Hurricane Katrina.. Source: ASCE. 2007. 听

听听听听听听听听听听听 The Army Corps of Engineers estimated finishing the Parallel Protection Plan by 2008; later adjustments pushed that date back to 2015 (Moreau 2006). Hurricane Katrina made landfall in Louisiana on August 29, 2005, ten years before levee refurbishment was set to be complete. Even if the levee construction had been completed before Katrina struck, the Parallel Protection Plan was still modeled after the Standard Project Hurricane, leaving the city of New Orleans at the mercy of a powerful Category Three hurricane (ASCE 2007). David H. Moreau, a researcher at the University of North Carolina at Chapel Hill, considers the history of the New Orleans levee system a 鈥渞epititious cycle鈥� of expansion and development, construction and protection, landscape manipulation and degradation, and failure followed by new development (2006, p. 11). Moreau criticizes the U.S. Army Corps of Engineers stating that they had an 鈥渙verreliance on 50-year-old forecasts鈥� that they used to 鈥渏ustify their projects鈥� (2006, p. 11).

听听听听听听听听听听听 The levee system in New Orleans that faced Katrina in 2005 was what the American Civil Society of Engineers called 鈥渁 system in name only 鈥� in reality it is a disjointed agglomeration of individual projects that were conceived and constructed in a piecemeal fashion鈥� (ASCE 2007, p 63). Had the system been built with congruencies throughout and based upon the maximum possible hurricane, catastrophe might have been averted.

Wetland Decline

听听听听听听听听听听听 Wetland decline has become a serious and complex issue for southeastern Louisiana. The wetlands provide ecosystem services by protecting inland regions from storm surges, functioning as sponges during heavy flooding events, and filtering out pollutants in the water (USGS Coastal and Marine Geology Program 2010). Over the past 150 years the Lake Pontchartrain watershed has been transformed by massive drainage of low-lying basins, cypress swamps, and marshes (Kindinger 2001). Estimates from the NASA Earth Observatory indicate that from 1937 to 2000 up to 35 square miles of coastal wetlands were lost per year, or approximately 1,900 square miles of wetlands disappearing in 63 years (NASA 2005). The three main causes of this swift wetland decline are natural land subsidence processes, rapid growth and urban expansion, and canal dredging (USGS Coastal and Marine Geology Program 2010; CWPPRA 2011; Van Heerden and Bryan 2006; Moreau 2006).

听听听听听听听听听听听 The wetlands of southeastern Louisiana are part of the Pontchartrain Basin watershed making up one of the largest estuaries in the United States (Kindinger 2001). The basin is situated to the east of the Mississippi River and extends northward through Jackson, MS (USGS Coastal and Marine Geology Program 2010). The southern extent of the Pontchartrain Basin joins with the Mississippi River Delta creating a landscape of fresh water swamps, brackish water estuaries, and salt water marshes (USGS Coastal Marine Geology Program 2010). The soils in and around Lake Pontchartrain are mostly comprised of silts, clays, and sands along with organic material such as leaf litter, shells, and rootlets (Kindinger 2001). These marshy soils are often saturated with water creating a highly compressible, unstable land surface (Van Heerden and Bryan 2006).

听听听听听听听听听听听 The American Civil Society of Engineers noted that, 鈥淣ew Orleans is sinking鈥� (ASCE 2007, p 8); the land undergoes a process known as subsidence, a natural process of soil compression due to the decay of the organic materials present in the soils (ASCE 2007). Before human intervention in the natural hydrology of New Orleans, land subsidence was counterbalanced by sediment deposition from the Mississippi River, maintaining an at-sea-level landscape; however, fresh sediment layers are now prevented from deposition over old layers due to the massive flood control systems established along the entirety of the Mississippi River (ASCE 2007). This has resulted in the below-sea-level surfaces present today. Hence, the flood control measures taken in the last two centuries, such as the construction of the Bonnet Carre Spillway, have actually sped up natural land subsidence processes creating a sinking city (NASA 2006).

听听听听听听听听听听听 It is important to note that the land is sinking when discussing wetland decline in southeastern Louisiana, because land subsidence has been attributed as one of the leading factors in wetland decline in the New Orleans region; land subsidence allows increased levels of salt water to infiltrate sensitive brackish water wetlands (CWPPRA 2011). Brackish water estuaries comprise 24% of the total wetlands in the Pontchartrain Basin, functioning as protective, salt water barriers for inland fresh water marshes and cypress swamps (CWPPRA 2011). Due to land subsidence, the brackish water marshes have been more susceptible to encroaching salt water from the Gulf of Mexico (CWPPRA 2011). Even subtle changes to the amount of salt water in a brackish water ecosystem can have severe consequences, such as the inability of wetland vegetation to adapt to the rapid changes in saline content resulting in high levels of plant die-off and wetland loss (CWPPRA 2011).

听听听听听听听听听听听 Increased saline levels in brackish water ecosystems is crucial for the Crescent City, New Orleans East, and the eastern bordering wetlands. New Orleans East historically has had the greatest land subsidence throughout the delta plain, and the region is already five to eight feet below sea level (NASA 2006). New Orleans East also has a large land area covered by wetlands and is bordered by the Borgne Land Bridge, the largest brackish water marsh in the region (CWPPRA 2011). The Borgne Land Bridge separates Lake Borgne and the Gulf of Mexico from Lake Pontchartrain, functioning as a line of defense from damaging storm surges (CWPPRA 2011). Research conducted by the Coastal Wetlands Planning, Protection, and Restoration Act Managing Agencies (CWPPRA), a conglomeration of NOAA, USACE, the National Resources Conservation Service, and more, has shown that since 1932 approximately 24% of the Borgne Land Bridge has been lost, largely due to land subsidence and the resulting spike in saline content (2011). Consequences from such a high rate of wetland decline include increased erosion along the shorelines of Lake Pontchartrain and Lake Borgne, further exacerbating the issues of wetland loss, and increased storm surges passing from the Gulf of Mexico through Lake Borgne to Lake Pontchartrain, putting more people and property at risk to flooding (CWPPRA 2011).

听听听听听听听听听听听 In addition to land subsidence, increased development of wetland regions has led to substantial wetland decline. When the population of New Orleans was booming in the late 1800s and early 1900s, areas outside of New Orleans Proper were sought for development (Moreau 2006). Figure 11 depicts the city of New Orleans before the districts of Lakeview and Gentilly were built in 1849 (ASCE 2007). The land cover feature that separated central New Orleans from Lake Pontchartrain was freshwater marshes and cypress swamps (Moreau 2006). The swamps acted as a buffer from lake-side flooding or flooding from storm surges that could assault New Orleans from the north, the same direction as one of the two main storm surges that Hurricane Katrina produced (ASCE 2007). As lakefront development was seen as the next best step for the city the swamps were drained, resulting in significant wetland die-off (Moreau 2006). Furthermore, soils from other wetlands were collected and redistributed in the form of floodwalls along the shores of Lake Pontchartrain to protect the new developments (Moreau 2006; USGS Coastal and Marine Geology Program 2010). This was known as the Lakefront Development Project of 1926 that resulted in significant wetland drainage and loss (Moreau 2006).

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Figure 11: Historical Map of New Orleans displaying former swamp lands to the north of the city. Source:听ASCE. 2007.

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听听听听听听听听听听听 In terms of development, the greatest devastation to local wetlands occurred between 1950 and 2000 when the brackish water, marsh land barrier east of the IHNC was urbanized. Deemed a 鈥渉igh-risk venture鈥� by the USACE because of its exceedingly low elevation, the federal government supported levee construction east of the IHNC so that new residential areas could be built, the region is now called New Orleans East (Moreau 2006, p 24). The notion that the New Orleans region would need additional residential land cover came from population projections modeled after the rate of growth from 1900 to 1950, in which the population of New Orleans doubled (USGS Coastal and Marine Geology Program 2010). However, the rate of population growth leveled out in the New Orleans area soon after the population boom, negating the full need of the New Orleans East developments (USGS Coastal and Marine Geology Program 2010). As a result, the wetlands were replaced by non-porous infrastructures that were not necessary to the city鈥檚 overall expansion, and the natural wetland barrier was destroyed.

听听听听听听听听听听听 In conjunction with the promoted development of New Orleans East in the 1950s, federal and state government also sought to build a shorter navigation route from the Gulf of Mexico to the Port of New Orleans (USACE 2012). The proposed canal would have a duel function as a safer shipping route while encouraging residential settlement in New Orleans East (USACE 2012). The canal was named the Mississippi River Gulf Outlet (MRGO, pronounced 鈥淢ister Go鈥�) and was completed in 1968 (USACE 2012). MRGO allowed ships to avoid the unpredictable mouth of the Mississippi River and saved shippers time by cutting off the remaining 120 miles of the winding lower Mississippi River (USACE 2012). Figure 12 displays MRGO beginning in the Gulf of Mexico and joining up with the IHNC.

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Figure 12: Map of MRGO 鈥� demonstrates quicker, more direct route to Port of New Orleans. Source: USACE. 2012. 听

听听听听听听听听听听听 Throughout its construction and usage, MRGO has had profound effects upon the surrounding ecosystems. The 38-foot-deep and 500-foot-wide canal was dredged through brackish water marshes, cypress swamps, and smaller bays (USACE 2012). In fact, the construction of the 75 mile long MRGO directly removed

27,600 acres of wetlands and salinized tens of thousands of additional acres of sensitive wetland habitats (Freudenburg et. al 2008). Rather than an 鈥渙utlet鈥�, MRGO functioned as an 鈥渋nlet鈥� for salt water to bombard sensitive fresh and brackish water vegetation (Freudenburg et al 2008). In addition, MRGO served as a funnel for the storm surge during Hurricane Katrina, which resulted in multiple levee breaches along the IHNC, the major cause of flooding in St. Bernard鈥檚 Parish, the Lower-Ninth Ward, and New Orleans East (ASCE 2007; Freudenburg et. al 2008). This flooding was not only problematic for people and property, but also devastated the surrounding wetland ecosystems (Freudenburg et. al 2008).

听听听听听听听听听听听 MRGO is just one of multiple canals that characterize the lower-river delta. Other canals have been constructed by oil and gas companies in order to better navigate the oil and gas-rich marshlands (Van Heerden and Bryan 2006). While MRGO and the canals constructed by the oil companies served to improve the navigation of the Mississippi River Delta, they did so at the expense of the region鈥檚 natural hurricane defense system (Freudenburg et. al 2008).

听听听听听听听听听听听 When Hurricane Katrina collided with southeastern Louisiana, the network of wetlands that protected the coastline had been hindered by an amalgamation of human influence and natural processes. Because of land subsidence and saline encroachment, development, and canal dredging, Katrina struck a deteriorating, sensitive landscape that was unable to function as an absorbent barrier. These factors have crippled the wetlands of southeastern Louisiana and may have exacerbated the damages produced by Hurricane Katrina.

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Social Vulnerabilities

听听听听听听听听听听听 The reasons for Hurricane Katrina鈥檚 destruction were not limited to preexisting features of landscape and piecemeal engineering. The citizens of the Mississippi River Delta were also struck by a storm that altered their lives forever. Estimates of lives lost during Hurricane Katrina range from 1300 to as high as 1800 (Richardson et. al 2008); yet, studies performed by NOAA and the NWS suggest accurate disseminations of warnings with sufficient time to evacuate the New Orleans region (Johnson 2006). Research by Joseph E. Trainor et. al suggests that non-evacuees were in fact aware that a powerful storm was headed their way (2006). With a functioning warning system in place, many were left questioning why there were such devastating consequences. Susan L. Cutter, Christopher T. Emrich, and fellow social scientists argue that 鈥渟ocial vulnerabilities鈥� of the non-evacuees resulted in a very high number of 鈥渆xcess mortalities鈥� or untimely deaths (Cutter and Emrich 2006; Trainor et. al 2006; Gall 2011, p. 159).

听听听听听听听听听听听 Social vulnerabilities are defined as 鈥渢he susceptibility of social groups to the impacts of hazards, as well as their resiliency, or ability to adequately recover from them鈥� (Cutter and Emrich 2006, p. 103). Social vulnerabilities are byproducts of preexisting social inequalities; they embody population characteristics such as age, gender, and class as well as personal factors such as physical mobility, knowledge and awareness of evacuation routes and emergency services, social networks, fears of looting or physical harm, and more (Cutter and Emrich 2006; Trainor et. al 2006). Trainor et. al describes people with social vulnerabilities as not having 鈥渢he means鈥� to evacuate or execute other self-protective measures (2006, p. 314). Many citizens of New Orleans were without the means, forcing them to weather the storm with limited resources and aid (Trainor et. al 2006).

听听听听听听听听听听听 Different social vulnerabilities have been identified as the primary cause of such high death tolls and such high rates of non-evacuation. Cutter and Emrich note that two of the greatest determinants of social vulnerability in Orleans Parish were race and class (2006). Most of the non-evacuees during Hurricane Katrina were lower-class, African-American citizens (Cutter and Emrich 2006). Cutter and Emrich note that 27% of this particular demographic did not own an automobile, hindering their ability to evacuate. Additional research by Melanie Gall indicates that age may have been the most influential social vulnerability during Hurricane Katrina (2011). An analysis of the victims of Hurricane Katrina indicated that 50% of the victims were older than 75 years old, and 85% of the victims were 51 years or older (Gall 2011). Although age itself does not necessarily make an individual more vulnerable, it鈥檚 correlated with reduced physical and mental abilities and chronic diseases (Gall 2011). This implies that many Katrina victims may not have been able to mobilize quickly, if at all, or comprehend the impending dangers.

听听听听听听听听听听听 Trainor et. al sights a different social vulnerability as playing a highly significant roll in the Katrina disaster. Trainor et. al interviewed non-evacuees asking why they did not or could not evacuate. Non-evacuees suggested the following reasons for remaining at home during the storm: physical immobility, financial limits/costs, lack of personal transportation, government failure to provide transportation, lack of knowledge of evacuation routes, lack of knowledge of public emergency protocol, cultural ties to neighborhood, weak personal and social networks, 鈥渨ishful thinking鈥�, past experiences, fears of robbery or looting, and the 鈥渘ormalcy bias鈥� (Trainor et. al 2006). Trainor et. al noted that 鈥渨ishful thinking,鈥� past experiences, and the 鈥渘ormalcy bias鈥� were the top three reasons among his interviewees for choosing to stay in New Orleans (2006). 鈥淲ishful thinking鈥� is what Trainor et. al defines as a psychological phenomenon people undergo during times of imminent threat in which they hope or pray that a natural hazard will redirect its course and not cause harm to themselves or personal property (2006). This mindset was a common problem among non-evacuees during Hurricane Katrina, placing them at greater risk than those who chose to heed the public warnings (Trainor et. al 2006). Similarly, the 鈥渘ormalcy bias鈥� kept people from leaving; this occurs when people feel as though emergencies are a routine, everyday occurrence and they should simply go on with their normal activities (Trainor et. al 2006). The 鈥渘ormalcy bias鈥� occurs in many emergency situations as a coping mechanism for those who do not trust in warning systems or the organization managing warnings (Trainor et. al 2006).

听听听听听听听听听听听 Trainor and his fellow researchers also discovered that past experiences with disasters impacted people鈥檚 decisions to stay (2006). Many of the non-evacuees had lived through Hurricane Camille in 1969; with Katrina being downgraded from a Category Five to a Category Three, they felt as though they could handle a weaker storm (Trainor et. al 2006). Past experiences often affect people鈥檚 behavior before, during, and after a disaster (Cutter and Emrich 2006); decisions that place them in greater danger are justified through the rationale that they have lived through a disaster before, so they can survive the next one (Trainor et. al 2006).

听听听听听听听听听听听 Lastly, Freudenburg et. al poses the idea that the overall concentration of populations should be considered when assessing the social vulnerabilities of the New Orleans populous (2008). In New Orleans, there was a large clustering of people in a high hazard region. This clustered effect is what Freudenburg et. al notes as setting the stage for the catastrophe in the first place (2008). If the population had not been so concentrated in a region renowned for its hurricane activity, Katrina would not have impacted so many lives (Freudenburg et. al 2008).

听听听听听听听听听听听 While different studies may suggest that certain characteristics outweighed others in terms of the capability of the New Orleans populous to plan, respond, and recover from Hurricane Katrina, the researchers all suggest that in most circumstances there was a multiplicity of social vulnerabilities that inhibited the application of survival techniques. Rather than there being one, dominating social vulnerability that dictated the nature of victimization, all factors interplay with one another creating an extremely vulnerable population in New Orleans. The academics mentioned above also suggest that not enough research has been done on social vulnerabilities and cite a need to prevent 鈥渢ragedies鈥� like Katrina from repeating (Freudenburg et. al 2008, p. 1029). Cutter and Emrich disapprove of 鈥渂road-brush approaches鈥� that create overarching formulas for addressing the social vulnerability issue. Instead they suggest individual and community level based planning that assesses who has the greatest need (2006, p. 112).

听听听听听听听听听听听 In sum, it is important to show that the citizens of New Orleans exhibited social vulnerabilities before Katrina struck, because these vulnerabilities were amplified during and after the storm. New Orleanians were unable to prepare for the storm due to these social vulnerabilities, and therefore were unable to defend themselves against the rising waters, resulting in a shocking death toll (Gall 2011). Furthermore, the social vulnerabilities that impeded evacuation of the residents of southeastern Louisiana were heightened because the piecemeal hurricane protection system and the diminished natural environment were unable to protect them.

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Future Mitigation and Conclusions

听听听听听听听听听听听 Three major reasons for the extent of destruction caused by Hurricane Katrina have been identified: piecemeal construction of the hurricane protection network, wetland loss, and elevated levels of social inequalities. These three factors contributed to the loss of over 1,500 lives, widespread damage, and the extreme financial burdens of recovery. There are many arguments that try to explain the devastation of Hurricane Katrina: government initiatives failed at nearly all levels (local, state, federal), FEMA lacked proper decision-making skills and capable upper-management personnel, or that too much emphasis within emergency management had been redirected to terrorism since the terrorist attacks on September 11, creating confusion in terms of protocol and policies. However, these critiques blame the storm鈥檚 devastation on short-term factors that emerged as a result of the storm. The reasons for disaster presented in this paper are long-term, preexisting conditions that created an environment vulnerable to Katrina鈥檚 power. Therefore, these preexisting conditions require mitigation efforts to lower the probability of another Katrina-like event.

听听听听听听听听听听听 By utilizing a tool developed by FEMA known as 鈥淪TAPLEE鈥� I have analyzed several potential ways in which we might lower the probability of another Hurricane Katrina catastrophe from occurring. STAPLEE allows emergency managers to assess the ways in which a proposed hazard mitigation plan is effective or ineffective. STAPLEE stands for social, technical, administrative, political, legal, economic, and environmental 鈥� the areas of society that would be affected by the mitigation plan. Social refers to community acceptance; technical refers to feasibility of a mitigation goal; administrative refers to capable staffing and allocation of funding; political addresses political support; legal looks at听 legal limitations and potential challenges to authorities; economic infers costs and benefits of a mitigation plan; and environmental addresses the impacts on surrounding habitats and effects on global environmental goals.

听听听听听听听听听听听 Based upon the three dimensions of disaster, Table 4 analyzes possible mitigation actions that have been proposed in the wake of Katrina to decrease the loss of life and property in the future. Each action is rated on each of the STAPLEE dimensions based on the history and assessment of the main causes of the Katrina disaster described earlier. Negative (-) symbols indicate an undesirable or impractical condition or outcome and positive (+) symbols indicate a positive condition or outcome; the zero (0) indicates a neutral or indeterminate condition or outcome.

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STAPLEE	Social	Technical	Administrative	Political	Legal	Economic	Environmental
Mitigation Plans
Levees: Do Nothing/ Abandon City	(-)听Historical significance of city is strong; public outrage would ensue	(-) Getting people out of the city will be a problem; unknown how to decommission a city	(-) Unclear how local government dissolves itself	(-) Heavy political opposition; some support as witnessed after Katrina	(-) Land ownership and compensation will likely cause multiple legal issues	(-) Large economic losses due to loss of major port/ tourist destination	(-) Pollution due to abandoned city not properly managed/ deactivated
Levees: Rebuild to Status Quo	(-) Public will be upset that standards did not improve	(0) Requires same technical operations as the past 40 years	(0) USACE would continue to be in charge of levee construction	(-) Political outcry due to lack of government initiative	(-) Lawsuits likely due to repetition of failed system	(-) High costs for levee system repairs	(-) Continued environmental degradation/ negative ecosystem effects
Levees: Address Engineering Problems/ Fix Height Problems and Different Materials Issues	(+) Public will support improving the levees to benefit their properties and safety	(-) May require removing some levees entirely; could be difficult	(0) USACE would continue to be in charge of levee construction	(+) May create political support for levee revamping	(+) May increase property values with revamped levees	(-) Higher costs due to improved levee building	(-) Continued environmental degradation/ negative ecosystem effects
Levees: Mitigate to Category Five Storm	(+) Public will support improving the levees to benefit their properties and safety	(-) May require removing all levees entirely; could be difficult	(-) Outside staffing needed to assess USACE鈥檚 Cat-5 storm protection	(-) May create political opposition due to tax increases	(-) Will likely cause home displacement and lawsuits over reclaimed land compensation	(-) Extremely high costs due to improved levees; may bankrupt city/ state	(-) Continued environmental degradation/ negative ecosystem effects
Mitigation Plans	Social	Technical	Administrative	Political	Legal	Economic	Environmental
Wetlands: Protect Wetlands/ Limit Public Use	(0) Public may support wetland protection; may be discouraged by land use restrictions	(0) Overall limited technical challenges	(-) May need more staff in U.S. Dept. of Fish and Wildlife or local wetland protection offices	(+) Public support for 鈥済reen鈥� actions taken by government	(-) Land restrictions may cause legal battles; issues with former land use capabilities	(-) Substantial costs due to erecting of barriers/ signs	(+) Environmental benefits due to decreased land disturbance/ possible wetland re-growth
Wetlands: Aggressive Reversal of Wetland Decline	(-) Banned use of public lands will create public outcry	(-) May be difficult to replant wetlands/ facilitate re-growth	(-) May need additional staffing to replant/ monitor wetlands	(-) May be seen as an overly aggressive political move	(-) Restricting land use may cause legal action from oil and gas companies	(-) High costs due to improving wetland regions	(+) Wetland re-growth possible; habitats restored
Vulnerabilities: Increase Community Planning/ Improve Evacuation Plans/Routes	(+) Public will support better evacuation plans and increased focus on poor areas	(0) Not a complex technical task	(-) Need to hire city planners to reassess evacuation routes and community education leaders	(+) Political support for helping the vulnerable	(+) Relatively minimal legal problems	(-) Some cost increases for paying staff members and city planners	(0) Not directly related to environment; may increase pollution from increased use of transportation
Vulnerabilities: Make Vulnerable Populations Only Focus of Hazard Planning	(-) Narrow focus of mitigation likely to upset other members of public	(0) Not a complex technical task	(-) Need to reassign staff; hire experts in social vulnerabilities and emergency management	(-) Political outrage over narrow focus of hazard planning	(-) Law suits over negligent government	(0) Narrow scope of emergency planning may free up money	(-) Environmental issues may be neglected altogether

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Table 4: STAPLEE tool assessing potential mitigation plans for the three major dimensions of disaster during Hurricane Katrina. Source: Created by Sarah McKinnell for 鈥淒imensions of Disaster: Landscape, Levees, and the Least Fortunate.鈥� 2012.

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听听听听听听听听听听听 Based upon Table 4, it is evident that the remedies to the piecemeal levee construction, wetland decline, and social vulnerabilities are complex. Utilizing STAPLEE as an assessment tool, however, can aid in deciding the next best steps for mitigation in New Orleans and in other coastal regions. Choosing to abandon the city and do nothing in response to the levee failure had negative results in every category of STAPLEE, indicating that this solution should not be implemented. Rebuilding the levee systems to the pre-Katrina standards had similar results, suggesting that this mitigation plan would be ultimately ineffective. Rebuilding the hurricane protection system to withstand a Category Five storm also produced negative effects. Although it would more than likely receive public approval so that there is not a Katrina-repeat, the feasibility of this endeavor could potentially bankrupt New Orleans, the state of Louisiana, and the USACE.

听听听听听听听听听听听 Addressing the previous engineering faults, however, may yield constructive results. Creating a unified, reliable hurricane protection system with conformity in construction materials, equivalent heights throughout, and constructed by a singular organization may provide viable hurricane protection throughout the New Orleans region. Cost increases can be expected, along with an increased difficulty in the technical engineering of the levees, but overall the public would support levee improvements that do not result in significant tax increases, as would be expected with redoing the levee system to withstand Category Five hurricanes. In addition, legal complications would be minimal and property values may even increase in New Orleans due to enhanced storm protection.听

听听听听听听听听听听听 Wetland decline would best be mitigated over a long-term time scale. By limiting public use of highly vulnerable wetlands and attempting to reconstruct wetland habitats, improvements may be seen over time; however, other factors play a role in wetland decline, such as land subsidence, which could hinder the wetland reclamation process altogether. Overly-aggressive actions that bar people access to job sites and recreational activities would more than likely damage the economy, have little political support, and bring about technical implication issues. Similarly, too much emphasis on populations with high social vulnerabilities may hinder New Orleans鈥� overall ability to react to disaster, because it neglects other populations that are at-risk as well. Increased community planning may help the most vulnerable populations in New Orleans by preparing them with the knowledge and tools to evacuate the next time a storm comes.

听听听听听听听听听听听 In conclusion, the mitigation efforts proposed and analyzed with the STAPLEE tool might improve the three preexisting conditions that exacerbated the disaster in 2005. With better community planning and emergency response tools, the people of New Orleans might reduce their social vulnerabilities and be better prepared for the next disaster. Further wetland decline might be prevented and re-growth could result in a more stable landscape. Future damages to infrastructure, property, and people might be prevented with adjustments and improvements made to the previous, piecemeal hurricane protection system. Learning from catastrophes and analyzing the conditions that generated widespread destruction allows mitigation planners, governments, emergency response organizations, engineers, and citizens to improve mitigation strategies and decrease the vulnerabilities of property and people.

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Afterword

听听听听听听听听听听听 In addition to increased community planning, wetland reclamation efforts, and addressing and improving upon the missteps of previous engineering, mapping can be used as a tool to improve upon these three dimensions of disaster. Through the use of modern mapping, including Geographic Information Systems (GIS), remote sensing, LANDSAT imaging, and more, vulnerable landscapes, levee systems, and populations can be identified and analyzed for future mitigation planning. For example, by combining U.S. Census data with terrain elevation data in a GIS, we can create maps that identify where high-risk populations reside, as well as which groups are more likely to experience flooding because they live below or at-sea-level. With these maps, emergency managers can focus evacuation planning and public awareness outreach on the identified vulnerable communities. This will ensure that when another disaster occurs, these communities may be more capable of defending themselves or be given priority in terms of where resources are allocated.

听听听听听听听听听听听 Mapping can also be used to show spatial 鈥� temporal relationships of the region鈥檚 natural habitats. By using LANDSAT imaging and other satellite imagery, we can map wetland decline or growth over time. This will allow emergency planners to identify areas with limited natural storm surge barriers. The USACE can run detailed analyses on storm surge patterns and wetland availability to assess where levees may need to be higher than expected due to a lack of a wetland barrier. Mapping can also be used to monitor levee construction progress. Richardson et. al noted that the USACE used maps that were 鈥渕ore than a decade old鈥� when constructing levees and floodwalls in New Orleans (2008, p 36). This is problematic especially when building a hurricane protection system on a landscape with significant land subsidence. The land surface data may have changed within that decade, creating substandard levees that do not meet height requirements. Similarly, events such as Hurricane Katrina can alter the landscape, entirely removing portions of land and changing local hydrologic systems (NASA 2005). Lastly, mapping can ensure better quality construction if conducted on a routine basis, which would improve the overall hurricane protection system.

听听听听听听听听听听听 Spatial analysis tools are fundamental to mitigation efforts, and mitigation efforts are essential for disaster resilient societies. With greater and more reliable use of mapping, emergency organizations such as FEMA can have eyes on a hazard zone before disaster strikes. Relationships can be predicted in advance based upon location, specific demographic characteristics, and established defense mechanisms in which people may be more susceptible to loss of life and property. By analyzing previous disasters, like Hurricane Katrina, we become aware of the shortcomings of human and environmental interactions. Wetland decline, piecemeal levee construction, and social vulnerabilities worked together to generate serious shortcomings for the entire New Orleans region. Mapping as a foundational tool for mitigation preparations can decrease these shortcomings and establish a greater understanding of the vulnerabilities all people exhibit in the face of disasters.

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References

American Society of Civil Engineers Hurricane Katrina External Review Panel (ASCE).听The New Orleans Hurricane Protection System: What Went Wrong and Why. Virginia: American Society of Civil Engineers, 2007.

Blake, Eric S., Christopher W. Landsea, and Ethan J. Gibney. 鈥淭he Deadliest, Costliest, and Most 听听听听听听听听听 Intense United States Tropical Cyclones from 1851 to 2000鈥� National Oceanic and Atmospheric Adminstration,听NOAA Technical Memorandum NWS NHC-6. 2011.

Coastal Wetlands Planning, Protection, and Restoration Act (CWPPRA). "The Mississippi River Delta Basin." USGS National Wetlands Research Center. Accessed October 3, 2012. 听听听听.

___.鈥淭he Pontchartain Basin.鈥� USGS National Wetlands Research Center. Accessed October 3, 听 2012.

Cutter, Susan L., and Christopher T. Emrich. "Moral Hazard, Social Catastrophe: The Changing Face 听听听听 of Vulnerability along the Hurricane Coasts."Learning from catastrophe: quick response 听听听听听听听听听听听 research in the wake of Hurricane Katrina. 葫芦娃视频, Colo.: Institute of Behavioral Science, 听听听听听听听听听听听 University of Colorado at 葫芦娃视频, 2006. 102-112. Print.

Freudenburg, William, Robert Gramling, Shirley Laska, and Kai Erikson. "Organizing Hazards, 听听听 Engineering Disasters? Improving the Recognition of Political-Economic Factors in the 听听听听听 Creation of Disasters."听Social Forces听87.2 (2008): 1015-1030. Print.

Gall, Melanie. 鈥淪ocial Dynamics of Unnatural Disasters: Parallels between Hurricane Katrina and the 听听听听 2003 European Heat Wave.鈥� In听Dynamics of Disaster: Lessons on Risk, Response, and 听听听 Recovery, edited by Rachel Dowty and Barbara L. Allen, 159-168. Washington D.C.: 听听听听听听 Earthscan, 2011.

Graumann, Axel, Tamara Houston, Jay Lawrimore, David Levinson, Neal Lott, Sam McCown, Scott 听听听听听 Stephens, and David Wuertz. 2006. Hurricane Katrina, A Climatological Perspective. 听听听听听听听听听听NOAA鈥檚 National Climatic Data Center Technical Report 2005-01. Asheville, NC: U.S. 听听听 Department of Commerce NOAA/ NESDIS.

Johnson, David L. 2006. Service Assessment: Hurricane Katrina August 21-31, 2005.NOAA鈥檚 听听听 National Weather Service. Silver Spring, MD: U.S. Department of Commerce 听听听听 NOAA/NWS.

Kindinger, Jack L.. USGS, "Holocene Geologic Framework of Lake Pontchartrain Basin and Lakes of 听听听听听 Southeastern Louisiana." Last modified October 17, 2001. Accessed September 18, 2012. 听听听听听 pubs.usgs.gov/of/1998/of98-805/html/kindingr.htm.

Kosovich, John J.,听State of Louisiana 鈥� Highlighting Low-Lying Areas Derived from USGS Digital 听听听听听听听听 Elevation Data听. 1:700,000. Map 3049. Washington, D.C.: USGS, 2008.

Miller, DeMond Shondell, and Jason David Rivera.听Hurricane Katrina and the redefinition of 听听听听听 landscape. Lanham: Lexington Books, 2008.

Moreau, David. "Levees and Land Use: The Making of a Disaster in New Orleans." InLearning from 听听听听 catastrophe: quick response research in the wake of Hurricane Katrina. 葫芦娃视频, Colo.: 听听听听听听听听听听 Institute of Behavioral Science, University of Colorado at 葫芦娃视频, 2006. 11-30.

National Aeronautics and Space Administration (NASA). 2005. 鈥淗urricane Katrina Floods the 听听 Southeastern United States.鈥� NASA Goddard Space Flight Center, New Orleans, 听 Louisiana.听Earth Observatory Terra-MODIS Imagery. Web. (accessed October 1, 2012).

___. "Subsidence in New Orleans." Last modified June 3, 2006. Accessed October 8, 2012. 听听听听听听听听听听.

National Oceanic and Atmospheric Administration (NOAA). 2006. 鈥淗urricane Katrina Flooding and 听听听听听 Spill Maps.鈥澨�听(accessed September 19, 2012).

___. 2007. 鈥淗urricane Katrina 鈥� Most Destructive Hurricane Ever to Strike the U.S.鈥� NOAA Home 听听听听听听 Page 鈥� Hurricane Katrina.听听(accessed September 19, 2012).

___. 鈥淟and Cover Data for Hurricane Katrina Impacted Areas.鈥� NOAA Coastal Services Center.听听(accessed September 19, 2012).

___. "Mississippi River Flood History 1543-Present." Last modified October 12, 2011. Accessed 听听听听听听听听听 October 8, 2012.听.

Richardson, Harry Ward, Peter Gordon, and James Elliott Moore.听Natural disaster analysis after 听听听听听听听听听听听 Hurricane Katrina: risk assessment, economic impacts and social implications. 听听听听听听听 Cheltenham, U.K.: Edward Elgar, 2008.

Rogers, J. D. "Development of the New Orleans Flood Protection System Prior to Hurricane 听听听听听听 Katrina."Journal of Geotechnical and Geoenvironmental Engineering. (2008): 602-617. 听听听听听听听听听听 10.1061/(ASCE)1090-0241 (accessed September 19, 2012).

Roth, David. 2010. 鈥淟ouisiana Hurricane History鈥�.听National Weather Service.听Camp Springs, MD: 听听听听听听听听 NOAA.听.

Smith, Keith, and David N. Petley.听Environmental Hazards: Assessing Risk and Reducing Disaster. 听听听听听听 New York: Routledge, 2009.

Trainor, Joseph E., William Donner, and Manuel R. Torres. "There for the Storm: Warning, Response, 听听 and Rescue Among Non-evacuees." In听Learning from catastrophe: quick response research 听 in the wake of Hurricane Katrina. 葫芦娃视频, Colo.: Institute of Behavioral Science, University of Colorado at 葫芦娃视频, 2006. 314-320.

United States Army Corps of Engineers (USACE) New Orleans District. 2012. "History of MRGO." 听听听 Accessed October 2, 2012.听.

United States Geological Survery Coastal and Marine Geology Program, "Geologic Framework and 听听听听听听听听 Processes of the Lake Pontchartrain Basin." Last modified March 10, 2010. Accessed October 1, 2012. coastal.er.usgs.gov/pontchartrain/.

Van Heerden, Ivor, and Mike Bryan.听The storm: what went wrong and why during hurricane Katrina. 听听听 New York: Viking, 2006.

Acid Rock Drainage in the Upper Snake River: The Presence of Heavy Metals in a Mineralized Watershed,听Garrett Rue

(Back to top)

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Overview

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The coupled environmental impact of acid rock and acid mine drainage is a problem facing countless waterways across the Rocky Mountains.听听Here we examine the Snake River watershed, located near the former mining boomtown of Montezuma. Over the three decades, researchers for numerous government agencies, the Institute of Arctic and Alpine Research, and graduate students at the University of Colorado have closely monitored changes here in water chemistry and heavy metal contamination present in its contributing streams, resulting from both over a hundred and fifty years of mining activities and the natural weathering of pyrite-laden rock.

The purpose of this project, funded in large part by an Undergraduate Research Opportunity Grant, is to test the dissolved metals present in the upper Snake River, an undisturbed portion of the reach that is naturally acidified and loaded from both surface and subsurface flow. Augmenting this data are field measurements of stream flow, pH, and total dissolved solids collected at a one-week interval between September 22nd听and 28th, 2012. The follow-up lab analysis of samples was performed by the Laboratory for Environmental and Geologic Studies using Inductively Coupled Plasma Mass Spectrometry to determine concentrations of Aluminum, Cadmium, Copper, Iron, Manganese, Sulfate and Zinc present at 15 sites distributed among the Upper Snake; the headwaters, 3 main tributaries and their conflux, and the confluence downstream with the pristine Deer Creek. Certain sites were chose due to availability of water chemistry data going back over 30 years, with others chosen because of their reflection of similar climate conditions at the time of sampling.听听By choosing sites which have been heavily studied and measured over a large temporal scale, it is therefore possible to correlate these new results with pre-existing data to draw new conclusion regarding the presence of heavy metals in the upper Snake River as to whether these levels have increased, further enrichment is occurring, and how these change in relation to drivers such as climate.

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Chapter 1

Background

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The Snake River is located west of the Continental Divide in the Rocky Mountains of central Colorado. A long history of hard-rock mining in the region and its location in the Colorado mineral belt, which supports natural weathering processes, is respectively responsible for the problem of Acid Mine Drainage and Acid Rock Drainage in the Snake River.听听The parent material from which these mountains were formed contains high concentrations of the mineral Pyrite. It is often called 鈥渇ools gold鈥� for it鈥檚 shiny resemblance to the real thing and the similar depositional features. But an interesting thing happens when water flows over this mineral. Ferrous iron, sulfate, and sulfuric acid are created through a redox reaction when water and oxygen interact. Bacteria can contribute by catalyzing the reaction, speeding up the rate in which the water becomes acidified. As these acidic waters move through a watershed, in the process coming into contact with other minerals and exposed rocks, they dissolve and mobilize more heavy metals like iron, aluminum, copper, cadmium, iron, and zinc. The following formula shows the reaction where Fe is oxidized and O2听is reduced, which creates as a byproduct ferrous iron, sulfuric acid, and reduces the pH of the water.

2 FeS2听+ 7 O2听+ 2 H2O听脿听2 Fe2+听4 SO42-听+ 4 H+

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This ferrous iron can now be further oxidized into ferric iron by extremophilic bacteria.

听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听4 Fe2+听+ O2听+ 4 H+听脿听4 Fe3+听+ 2 H2O

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These heavy metals can also precipitate out when this acidic water is neutralized with more pristine waters, which are then deposited on the rocks and streambed material of a river. Visually, it looks as if the rocks and river bottom have been painted with metals, be it the chalky silver sheen of aluminum or the red rusting of iron, with continued exposure to air furthering these processes. Due to the decreased solubility of certain metals from rising pH conditions, here we see how ferric iron precipitates out of water as ferric hydroxide to coat the streambed.听

听听听听听听听听听听听听听听听听听听听听听听听听4 Fe3+听+ 12 H2O听脿听4 Fe(OH)2听+ 12 H+

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As more ferric iron is rendered into the stream, it also accelerates the oxidation of other pyrite-bearing minerals from which the water may contact. This highlights a significant increase in hydrogen ions and more sulfuric acid to which pH will further decrease, acting to further the dissolving of metals.

听听听听听听听听听听听听FeS2听+ 14 Fe3+听+ H2O听脿听12 Fe2+听+ 2 SO42-听+ 16 H+

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In the case of the Snake River, the problem of reduced pH and metal-enrichment is worsened further by later tributaries such as Peru Creek that are themselves laden with metals because of mine drainage. Where metals such as iron and aluminum precipitate out when pH conditions normalize, others such as zinc remained dissolved in the water column and present a serious challenge in maintaining water quality downstream.

Although the Snake River, along its contributing creeks and streams, has levels of metals that seriously affect stream ecology and biotic life, the nature of its sourcing being both due to natural weathering and the legacy of mining in the area makes it difficult to address.听Some of these metal concentrations well exceed limits of toxicity set by the state and mandated federally through the Clean Water Act, particularly zinc; however it is important to note that they present a minor health risk to human beings. The Snake River is only 15 miles long and flows into the larger Blue River, later discharging into the Dillon Reservoir. And even though this reservoir serves as a source of drinking water for Denver, this water becomes so highly diluted and neutralized from other water sources downstream as well as groundwater contribution that it possesses no serious threats to human health. Taking this into account, along with the high projected costs of mine site cleanup, and the metal enrichment already taking place naturally in the upper Snake, it has remained a low priority for state and federal cleanup efforts even though it represents one of the most contaminated watersheds in the state. Even if millions of dollars are spent on addressing even a priority site such as the Pennsylvanian Mine, natural metal loading would still take place and such cleanup may yield marginal results. In this regard, it may never be possible for certain parts of the Snake River to become compliant with clear water standards set by the EPA.听

The Snake River currently cannot support a self-sustaining fish population due to the concentrations of metals proven toxic to aquatic life. The Colorado Department of Wildlife stocks this river periodically, to maintain the indigenous populations; however this is a losing battle due to the coupled impact of acid rock drainage and acid mine drainage on water quality. In an effort to better understand these influences on water quality by ARD and AMD, the Snake River Task Force was founded. This highlights a partnership between the following stakeholders:听Colorado Department of Public Health and Environment, EPA, Keystone Ski Resort, the Blue River Watershed Group, and conservation groups such as Trout Unlimited. These partner groups have extensive experience with abandoned mine cleanups.听听The focus has centered on understanding the factors that influence water quality, as improvement proves difficult due to murky issues regarding liability as outlined in the Clean Water Act, high costs, and prior failed attempts at mitigation by the Colorado Division of Minerals and Geology in the 1980s. It鈥檚 important to again note that even serious reductions in AMD only represent part of the problem; as to date there are no remediation strategies for ARD. Therefore, it is possible that the Snake River will never meet the water quality criteria necessary to support fish and a rich aquatic biota.听听

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Chapter 2

Site Description

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听听听听听听听听听听听听This particular project, adapted from a previous study completed in 1998 by a partnership between Institute for Arctic and Alpine Research and United States Geological Society, focuses on a 4.55 square mile upper portion of the Snake River that serves as the headwaters for the catchment. The valley floor is largely bog iron ore, with portions of glacial till on the western slope and further down the reach (north). Sedimentary rock known as the Idaho Springs Formation is the predominant material from which the surrounding mountains are composed; however, there are small deposits of Quartz Monazite at the southern most portion of the valley. Silver Plume Granite deposits are also present on the eastern slope, roughly half way down the valley.

Figure 2.1

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Study Sites

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听听听听听听听听听听听听There are six tributaries of the upper Snake River; however, only three were flowing beyond a trickle during the time of sampling. This was due to warm temperatures in March, which facilitate an early spring melt, and the above-average snowpack quickly disappearing to leave only 19% of average on May 1st.听听These conditions and the summer drought to follow were greatly similar to those to the 2002 diel sampling study performed by Laura Belanger. Due to this, her previously evaluated sites, which were also based off the earlier study (Boyer et al., 1999), were chosen for this project to help correlate results with pre-existing data sets in periods of reduced flow. Measurements for pH, TDS, and temperature were collected at each site as well, in some cases at a temporal interval of one week to highlight any change in stream chemistry. Stream discharge was also measured via pygmy meter at multiple spatial and temporal intervals, to indicate any changes in flow or possible addition contributions by lateral inflow of groundwater.

听听听听听听听听听听听听At each site, samples were taken from both the Snake River and tributaries 10 meters above the conflux as well as 25 meters below the mixing zone. This was the protocol outlined in previous studies and such distance is necessary to maintain that samples not influenced by overlap of hyporheic zones. Additional samples were听听taken from the headwaters (0m) to establish baseline loading and pH of the Upper Snake, as well as at interval sites located at 1875m and 1935m to coincide with previously collected data. Further downstream, at the confluence of the Snake River and Deer Creek, each stream and their confluxes were sampled to better understand how a pristine stream serves to alter the water chemistry and precipitation of metals.

听听听听听听听听听听听听听Figure 2.2

USGS Topographic Map, Montezuma Quadrangle, 1:24000

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Site Conditions

听听听听听听听听听听听听Late September was chosen as the best time for sampling. According to 30 years of USGS stream flow data, this is a period of lowest flow and least contributions of 鈥渘ew鈥� water. In 2012, further exacerbating this trend was an early snowpack melt and dry summer that reduced flows of the Snake River to near-record lows. During times of sampling, the USGS gauge station near Keystone showed relatively similar levels of discharge on between days (9/22 and 9/29) and highlight that flows are well below median daily values over the last 63 years of collection. Using pygmy meter measurements of discharge below the Snake River and Deer Creek, it was possible to correlate these measurements for accuracy with its estimated 20% contribution to the gauge at Keystone (Boyer et al., 1999).

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听听听听听听听听听听听听听听听Figure 2.3

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Methods

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听听听听听听听听听听听听Sample collection will be done according to the Colorado Department of Public Health and Environment鈥檚 methodologies and standards for testing surface water (CDPHE, 2001) along with EPA Method 200.8. Samples were collected in 60ml HDPE plastic containers, with a sample volume of no more than 50ml.听听Prior to collection, each container was first bathed overnight in a 3% mixture of above reagent-grade nitric acid in ultra-pure deionized water, followed by two flushes of ultra-pure deionized water, then left to dry. During collection, samples will be acquired through 60ml syringes, with .45 um nylon filters to prevent colloidal or eigencolloids contamination. After collection, samples will be labeled with their respective pH, total dissolved solids, and then acidified with trace-metal-grade nitric acid to a value near or less than 1.5 for laboratory analysis. A field blank was prepared using ultra-pure deionized water, also acidified to the same value, to quantify any further possible contamination from containers or acids used. Samples will then be delivered to the Laboratory for Environmental and Geological Studies for ICP-MS (metals) and IC (sulfate) analysis.

听听听听听听听听听听听听In-site measurements of pH and total dissolved solids were obtained using Eutech instruments that were calibrated twice daily, and rinsed between sampling. Interval measurements of one week were also made to indicate any significant changes in stream chemistry. Discharge measurements were also made using a USGS Pygmy Meter (model 6205) at the Snake River and Deer Creek confluence on September 22 and 29, and at select points of the Upper Snake on September 29.

听听听听听听听听听听听听Included in the results/analysis section is historical data from the Boyer diel study completed in July of 1998, particularly because sites for this project were chosen from here to allow for corollary comparison. Due to the low-flow conditions observed prior to this project, certain sites were omitted because of a lack of measureable discharge. More recent studies (Belanger, 2001. Crouch, 2009), which took place during times of similar climate conditions and flow, further focused on certain tributaries of upper Snake River as significant sources of metal loading. Accordingly, discharge measurements were taken at select points above and below site (trib) 2095, a previously identified major source of enrichment, to provide insight into听concentration and subsequent dilution of solute metals in terms of mass balance. However, due to changing lateral inflow of groundwater at this site and only a single discharge measurement, these mass loads were highly inaccurate when compared to concentrations observed with ICP-MS analysis. Due to more accurate discharge measurements, which were corollary at 20% of that recorded by the USGS gauge station at Keystone, mass loads were instead calculated for sites SN-2 and SN-3, which lie above and below the confluence with Deer Creek. The following equation was used for calculating actual mass metal loads per unit time (sec) at a particular site.

Mx听= QxCx

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This equation was used to estimate mass loads using known values for discharge and concentrations of metals above the sites of confluence, and was also rearranged algebraically to solve for estimated concentrations above the confluence using observed concentrations from below.听

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Schedule

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鈥� 9/22: Collect initial pH, TDS, and discharge measurements, as well as samples from select sites.

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鈥� 9/29: Collect primary samples from 13 sites, as well as auxiliary measurements of pH, TDS, and discharge to quantify any change in stream flow or chemistry from previous week.

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鈥� 9/30: acidify samples, catalog data, and deliver samples to LEGS

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鈥� 10/13: Collect secondary pH and TDS measurements from select sites

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Chapter 3

Literature Review

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The purpose of this project is to better understand the metals present in the contributing streams of the Snake River. Through the testing of 4 sites within the Upper Snake, collecting samples at the confluences of contributing streams and their respective tributaries, concentrations and sources of metal loading can be evaluated.听听In particular, where smaller streams conflux with one another and how their heavy metal concentrations change relative to water volume (discharge).听听By also collecting field measurements of pH, TDS, and temperature at time of sampling, it can be further understood how water chemistry changes throughout this upper portion of the river and which tributaries are most influential. It is through the establishment of these baseline levels of metal loading present at the headwaters of the Snake River that a standard of water quality can be created in which to evaluate other sources of contamination such as acid mine drainage, which has a significant role in this watershed.

听听听听听听听听听听听听The compounding of acid rock drainage with acid mine drainage has served to worsen water quality in areas such as the Snake River watershed. This is certainly the case for other places located in the Colorado mineral belt; in the town of Silverton both processes are also serving to exacerbate the levels of metals that are discharging into streams. As a result, 3 out of 4 indigenous fish species have disappeared from portions of the Upper Animas River (Church et al., 2000). To a lesser degree, this is also the case for the Snake River and the coupled worsening of water quality due to these two factors. However, because ground waters in the Snake River area percolate through bedrock rich in conservative elements, and because multiple high-order streams such as the North Forks and Deer Creek are relatively pristine, acid drainage tend to be neutralized and diluted further down the catchment.

听听听听听听听听听听听听Long-term data sets of precipitation, temperature, and river discharge at many sites throughout the Colorado Rockies show decreasing trends in summer flows (Rood et al., 2008). These correlate to other, more recent findings, which highlight a snowpack that is melting 2-3 weeks earlier (Clow, D. 2010). Using snow water equivalent measurements from SNOTEL sites nearest to the Snake River, a trend was shown between advancement of peak stream flow by an earlier melt season and rising metal concentrations in summer months (Todd et al., 2012). A thirty-year water chemistry data set from the upper Snake River further shows that fluctuations from 100-400% of baseline are occurring during these low-flow months. However, these increases cannot simply be explained by shifting snowmelt timing or by decreased dilution from reduced discharge. It has been postulated that increasing temperatures observed in the Rockies over the last few decades could affect the rates of oxidation of sulfide minerals, but there is uncertainty that this can account for such drastic increases in metals. The coupled influence of all these factors, including their relation to dropping water tables due to reduced recharge of groundwater, and how there is more exposed rock because of reduced snow cover and duration, which also increases rates of weathering, are all explicitly linked and appear to be driven by changes in climate.

听听听听听听听听听听听听Between 2001 and 2005, a study was done to deduce the quality of groundwater prior to mining at an active site near Red River, New Mexico. An un-mined catchment nearby was also evaluated to provide an analogous idea as to the groundwater composition. It was discovered that two types of water are dominant here, which related to their overlying geology and location. The headwaters of the Red River are fed by springs buffered by conservative elements such as carbonate, keeping groundwater pH around 7.5-8.5.听听At middle and lower portions of the Red River, it was found that the water chemistry was vastly different and altered by acid drainage and mineralized water discharging into these lower reaches both above and alongside the mine site. Similar to the Snake River, these acid mineralized waters were formed from debris created by weathering and rapid erosion of pyrite-bearing minerals. Also observed at the site was how rainstorms had large impacts and alterations on the water chemistry of the Red River. This was further confirmed by later analysis of BLM historical data between 1982-1985. The increase in discharge in the spring due to snowmelt served to dilute solutes present in the river, with their concentration continually rising through the dry season until the next snowmelt. If a lackluster snowpack occurred, and no definitive peak in spring discharge, these concentrations continued to rise. Rainstorms in the summer served to slightly dilute these mineralized water systems, but more importantly it was observed that heavy rains actually reversed this diluting trend to create a drastic increase in metal concentrations such as zinc and a profound drop in pH from roughly 7.8 to 3.8. Here we see a flushing effect from an extreme rainfall event, with materials effloresced from evaporation due to prolonged drought being washed into the river. Another interesting observation was that the highest levels of metals and sulfate in the Red River occurred during an intense rainstorm in the valley, where no mining activities take place. This highlights that natural acid rock drainage can serve to alter water quality just as severely, if not more, than acid mine drainage. This becomes an important acknowledgement when we look to understand water quality in areas with high amounts of exposed sulfate-bearing minerals that have undergone mining actives, as well as how changes in precipitation frequency and intensity can serve to alter water quality.

听听听听听听听听听听听听In the context of these examples of ARD and AMD from differing areas across the US, the aforementioned author of the study, D. Kirk Nordstrom, translated these processes within the context of available long-term climate data and hydrologic change. Particularly troubling was that in 2009 the western U.S. experienced an increase in average temperature upwards to 70% higher than that of the global average. These changes were analyzed in relation to such influencing factors as the Pacific Decadal Oscillation (PDO), El Nino Southern Oscillation (ENSO), North American Monsoon (NAM), and global warming. Though these oscillations all act on differing scales, where ENSO serves to alter weather patterns for a few years and PDO acts on a longer time scale, their combined oscillations can serve to compound the effects of climate change, or help reduce the effects of each other. Careful examination of climate records dating from 1948-2000 in the Sierra Nevada, Rocky, and the Pacific Northwest mountains showed a quickening of snowmelt streamflow timing by 1-4 weeks (Dettinger et al., 1995). This shift in snowmelt has serious consequences in terms of acid rock and mine drainage for the following reasons: it extends the summer dry period, increases the rates of evaporation that leave more residual effloresced salts and decreases the time in which they may accumulate. It is also important to note that in terms of global warming, warmer temperatures have the potential to decrease rainfall frequency and increase the intensity of rains when they do occur. This again has large, looming implications in terms of water quality as it relates to AMD/ARD. As was demonstrated in the data, intense storms had the tendency to reverse the trend of metal concentration dilution and to instead flush higher and higher levels of metals into the studied catchments.听Therefore, greater shifts in climate, whether听due[DA1]听to natural or anthropomorphic causes, have the potential to further mobilize acid rock drainage and worsen its effects by increasing the frequency of these flush-out events. Though not specifically mentioned in this study, recent work has highlighted that a decreasing snowpack, whether due to climate change or not, can further the problem of acid rock drainage because it leaves more exposed, mineral-laden rock to be weathered by less frequent, more intense rainfall events.

听听听听听听听听听听听听The impact of acid rock and mine drainage on the water quality of the Snake River watershed has led to numerous studies to quantify sources of metal loading and their respective amounts over the last 30 years. In 2001, a grant from the EPA andNational Science Foundation supported an 11-month University of Colorado/INSTAAR project to assess this issue. Across numerous sites in the watershed, sampling was done during periods of high flow (Spring) and low flow (Summer/Fall), in order to observe how heavy metal concentrations changed seasonally. It was observed at most study sites, many of which are shared with this study, that concentrations were at their highest during the summer and decreased as snowmelt contributed to streamflow. Follow-up studies in 2010 evaluated groundwater contributions and subsurface metal loading through tracer analysis in the Upper Snake. More recent research has focused on interpreting long-term data from this area to establish trends in metal loading in relation to influences such as climate change (Crouch, 2011).

The most recent study, done in partnership by the USGS, EPA, and INSTAAR, evaluated increases in metal concentration in the Snake River utilizing the entire 30 years of available water chemistry records, and focused particularly on the influence that climate change may be playing in exacerbating a decrease in water quality. Correlating these large increases in metals with long-term climate, snowpack, and observed hydrologic measurements, a trend can be established between warmer temperatures, decreased stream flow, and earlier shifts in spring melt as having a major influence on a decrease in water quality. Because the study focused on analysis of large temporal and spatial records, as well as combining previous research on changes in Colorado climate (Clow, D. 2010) utilizing similarly comprehensive data, there are valid concerns on how anthropomorphic influences are altering water chemistry and metal concentrations in high alpine streams. Accordingly, as it is estimated that some form of acid rock or acid mine drainage affects over 40% of the headwaters in Colorado rivers and streams (Forhardt, 2003), there are serious implications as to how this may play out in the future. If the trends indicative of this research are indeed correct, then climate change and its influence on the hydrology of the Rocky Mountains are cause for concern. Decreasing water quality not only disrupts biotic communities, disturbs delicate stream ecosystems, and endangers indigenous aquatic species, but can also affect later utilization in terms of recreation, drinking water sourcing, along with other human uses.听听

听听听听听听听听听听听听The inherent variability of factors that drive our climate can serve to exacerbate or reduce the impacts of acid rock drainage, but the problem will not simply go away. The shown variability in metal concentrations has serious implications for both water quality and the ecology of the Snake River. The natural metal-enrichment occurring in the Upper Snake already makes this portion of the stream all but inhabitable for aquatic life. Only a few species of benthic invertebrates are able to survive in such extreme conditions.听听Flushing events similar to those documented in New Mexico by Nordstrom are quite possible here, if not inevitable in years of earlier snowmelt and prolonged summer drought. Instances of mass fish kills have already been observed after large flood events in the watershed when sediments and precipitates have washed from primary sources of contamination, such as the Pennsylvania Mine, into Peru Creek which confluences downstream with the Snake River (Berwyn, 2007). There remain portions of the Snake River and Peru Creek that cannot support self-sustaining fish populations, and rely on stock efforts by state wildlife officials to maintain their presence. Zinc concentrations also remain well above clean-water standards.

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Chapter 4

Results

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Field Observations:

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听听听听听听听听听听听听In an effort to provide a better understanding as to the steady state of water chemistry of the upper Snake River, measurements and sampling were done in a one-week time series. In addition to water sampling, discharge rates, pH, and total dissolved solids measurements were taken throughout the reach as well as the downstream confluence with Deer Creek. All measurements were collected within 2 hours of the time taken the previous week, many within 1 hour, so that any diurnal fluctuations were minimized.

听听听听听听听听听听听听The headwaters of the Snake, marked as Site 0, showed the highest pH measurements and lowest total dissolved solids. This provided a suitable baseline level and a basis of comparison for observations further down the reach.

听听听听听听听听听听听听Site 450, above tributary 460, showed slightly more acidic conditions, but only marginal increases in conductivity. Slight precipitation of iron was visually present and water temperatures here were near identical to the previous site, suggesting no additional subsurface inputs. The tributary itself, however, had the second lowest measurements of pH and second highest level of conductivity recorded. Visually reinforcing this data was an entire streambed coated in iron which continued for at least 10 meters below its confluence with the Snake. Below the confluence, at Site 485, we see a rebound of pH and total dissolved solids to levels similar to those above the conflux.听

听听听听听听听听听听听听Site 900, tributary 915, and the confluence at 940 showed near identical levels of tds, pH, and temperature which continued for a further 1000 meters, as corroborated by readings at sites 1875 and 1935. Iron precipitation was still present throughout this section, although still relatively minor.听

听听听听听听听听听听听听Previous research from tracer experiments suggested that site 2095 had additional groundwater inputs听听(Crouch, 2011). This was also evident in measurements taken by the presence of significant decreases in water temperature and conductivity from a point above the road (a2095) to 25m below (2095b). Differences in pH were also observed, with dilution by groundwater seemingly increasing pH as well as reducing the amount of solids dissolved in solution. Accordingly, iron precipitates were highly visible in the streambed of tributary 2095. Upon mixing with the Snake River (2120), a reduction in acidity occurred and total dissolved solids decreased. Discharge measurements were taken at this site on 9/29 to show how high concentrations with relatively low volume were further diluted by the dominant Snake River flow.

听听听听听听听听听听听听Further downstream, above the confluence with Deer Creek, the conductivity of the Snake River had increased as well as a slight increase in pH. Iron precipitates were also visually present here. Upon mixing with Deer Creek, a radical change in pH and conductivity occurred. This is likely due to the pristine sourcing of Deer Creek, combined with its high pH and extremely low total dissolved solid. Immediately noticeable at this conflux is a color gradient of orange (iron) and white (aluminum) precipitates. Further downstream, at sample site SN-3, pH increased and conductivity remained at over double that which was present in Deer Creek. The chalky silver coating on the streambed here suggested that aluminum was now the predominant precipitant, with any remaining metals present in solution to likely remain insensitive to low pH conditions. Metal mass balance calculations will be possible with ICP-MS results and discharge measurements to confirm this.

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Field Data:

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pH & TDS

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September 22nd

Site	pH	TDS	temp 漏
1875	3.56	200	9.2deg
1935	3.57	200	9.3deg
2085	3.46	200	13deg
听听听听听听听听听a2095	2.93	1020	8.6deg
听听听听听听听听听b2095	3.36	530	5deg
2120	3.52	240	12.1deg

September 29th

Site	pH	TDS	temp 漏
0	4.34	110	9.5deg
450	3.73	140	9.4deg
460	3.18	450	9.3deg
485	3.66	160	9.7deg
900	3.56	200	7.8deg
915	3.58	200	5.2deg
940	3.58	200	7.7deg
1875	3.55	210	3.2deg
1935	3.56	210	听
2085	3.55	210	5.2deg
2095a	3.02	1100	3.1deg
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2120	3.55	240	6.0deg
Snake River above Deer	3.65	310	7.2deg
Deer Creek	7.75	60	7.3deg
Snake River below Conf	4.83	140	听

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听听听听听听听听Figure 4.1

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Discharge

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听听听听听听听听听听听听听Figure 4.3

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ICP-MS & IC Results

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Chapter 5

Analysis

Sulfate

听听听听听听听听听听听听The presence of sulfate as a byproduct of the weathering reaction of pyrite serves as an important proxy for determining flow source. Samples were analyzed by LEGS, using Ion Chromatography, providing concentrations present in the solute. In evaluating the data, it is clearly evident that the source of sulfate is in the upper Snake River. Tributaries 460 and 2095, which both had extremely high levels of dissolved metals, show a similar trend in sulfate concentrations. This is indicative of a weathering as well as contact with mineralized material as the water percolates through the subsurface. Water temperatures well below what was observed upstream of these tributaries further hint that lateral inflow was making significant contributions. Of additional interest is how high these concentrations are above that which was measured in 1998, although the higher mean discharge values of July are much greater than those of September. This would hint that as inputs of 鈥渘ew鈥� water decrease, and snowmelt tapers off, sulfate solute concentrations rise to the corresponding lack of dilution occurring.

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听听听听听听听听听听听听听Figure 5.1

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As previously detailed, the reaction in which sulfate is generated also creates hydrogen ions.听听With this established, a clear relation between changes in pH, the rendering anions, and the subsequent dissolving/mobilization of metals is exhibited. Here we see a statistically significant (r2>95%) trend between observed pH and measured sulfate concentrations for both sampling days.听听As similar levels were observed at sites tested a week apart, this process would appear relatively intransigent.

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Aluminum

听听听听听听听听听听听听As aluminum is a metal that is sensitive in terms of solubility to pH, we expect to see high concentrations that correlate to observations of low pH along the upper Snake River. Tributary 460, which had high amounts of sulfate present, showed significant levels of dissolved aluminum, at least a four-fold increase from that recorded in 1998. Though again this does not account for differences in discharge that would serve to reduce concentrations through dilution.听
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听听听听听听听听Figure 5.2.1

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Assuming an average water hardness value of 41 mg/L (Boyer et al., 1999) to calculate CDPHE Aquatic Life Standards, it is very clear just how high these aluminum concentrations are in comparison. The logarithmic scaling highlights a difference by nearly 2 orders of magnitude at its highest concentrations. This infers how these concentrations change relative to observed pH, particularly, how pristine inflows such as Deer Creek make drastic reductions in dissolved concentrations of aluminum. Despite reductions, aluminum levels still remain high enough to be acutely toxic to most aquatic species.

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听听Figure 5.2.2

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But if these concentrations are falling with the neutralizing effect of high pH, with pristine waters present beyond the amount needed for dilution to occur, then what explains the significant mass reductions? Using discharge measurements and known concentrations from lab analysis we are able to calculate a mass balance to help explain this. Through a mass load calculation outlined in the methods section, we can empirically solve for the unknown mass load after the confluence of the Snake River with Deer Creek and additionally compare this with the actual observed concentration. As seen in the results, taking into account the dilution occurring by Deer Creek inflow, a significant reduction in dissolved aluminum mass is occurring. This can be attributed to its precipitation from solute due to the rise in pH that makes such high levels no longer soluble. This is also visually evident in this portion of the reach below the confluence, as chalky silver residue coats the streambed.

听听听听听听听听听Figure 5.2.3

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Cadmium

听听听听听听听听听听听听Cadmium is an extremely toxic metal that is often found in zinc ores. Concentration levels of cadmium observed in upper Snake River were relatively low throughout the headwaters, with notable increases in tributaries as well as below their conflux. The concentrations observed below Trib 940, which extends to Site 2086(m), seemed governed by in-stream processes and chemistry. However, Trib 2095 exhibited a concentration almost 10 times above those observed below Trib 940. When compared to Trib 460, which has similar pH/TDS characteristics and similar trends in metal concentrations, this was still exceedingly high. The differing geology of this tributary is perhaps responsible for the increased loading observed, with granite being the predominate material in which (low pH) groundwater would contact and hence dissolve.听

听听听听听听听听Figure 5.3.1

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There is an overall lack of definitive information regarding the toxicity of cadmium in terms of an Aquatic Life Standard (EPA, 2001), as there is no testing method known to accurately express this. However, cadmium is regulated and listed as a primary contaminant for EPA Clean Water Standards its concentrations pertain to drinking water. Regardless of water hardness, the maximum levels for cadmium allowed is 5 ppb or 5 ug/L. In the graph below we see that much of the upper Snake is well below this amount with only a slight exceedance at Trib 460. Although further downstream we see that Trib 2095 is well above this amount. But 25m below the conflux these levels are highly diluted and levels of cadmiun concentration fall very near to the standard again. Between Site 2120 and SN-2 further enrichment is occurring. This is perhaps due to the river flowing through a noted iron bog, but again cadmiun levels fall below 5 ppm just after the conflux with the pristine waters of Deer Creek.

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听听听听听听听听听听听听听听Figure 5.3.2

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From the calculated and actual mass loads above and below the confluence with Deer Creek, there are slight differences that would indicate precipitation is occurring. But it鈥檚 important to note that due to the variability between calculated loads versus actual loads, this amount could be well less than the 100 ug/s observed.听听听

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听听听听听听Figure 5.3.3

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Copper

Concentrations of copper observed through the upper Snake River show a much differing distribution than other heavy metals. Though Trib 460 and 2095 exhibit spikes in concentration. Copper levels are not much higher than measurements taken in 1998, which could again be explained by differences in water inputs, discharge, or dilution. Particularly interesting is that Trib 915, which showed almost no elevated metal concentrations above stream baselines across the panel, is the highest concentration. This tributary shared nearly identical physical characteristics with the Snake River in terms of pH, TDS, and temperature, so this is a peculiar result. This is also indicative of surface in-stream loading of metals as there is no indicators of lateral inflow or seepage that are present at other tributaries.听

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听听听听听听听听听Figure 5.4.1

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Again, using an average water hardness value of 41 mg/L (Boyer et al., 1999) to calculate CDPHE Aquatic Life Standards for copper, we see that concentrations observed above Trib 915 are actually lower than historical data. This is the only metal to exhibit this trend. This further supports the idea that in-stream processes are the primary enrichment source. Periods of lowest flow and least water inputs, such as September, show an inverse relationship with the levels measured in July of 1998. Trib 2095, a primary loading source of other metals, here shows only slightly increase above 1998 data.听听Of further concern is how elevated copper levels remain through the remainder of the reach, exceeding acute toxicity levels even below the confluence with Deer Creek.

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听听听听听听听听听听听听听Figure 5.4.2

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From computing the mass loads, there is evidence of precipitation occurring. Though we again see a variation between calculated and actual measurement, so the amount is likely well less than the .8 mg/s.听

听听听听听听听Figure 5.4.3

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Iron

听听听听听听听听听听听听As iron is implicit in the creation of acid rock drainage, we can draw similar conclusions to its concentration as proxy for pyrite weathering. Throughout the upper Snake River, it appears that iron concentrations are well above historical data. Similar to copper, this can be possibly explained by periods of decreased flow, such as September, having less water inputs to dilute. But because 2012 had a premature snowmelt this could have additionally exposed more (pyrite-laden) rock sooner than normal, therefore increasing the rates of weathering. Trib 460 shows an extremely high level of dissolved iron, much higher than that observed elsewhere, which was very visually evident for there was a reddish rust coating on the streambed of both the entire tributary and 25m downstream from the confluence where the sample was collected. The peaks in concentration at Trib 460 and 2095 are similar to those of aluminum, although significant variations between 9/22 and 9/29 support the inherent variability of iron concentrations due to photochemical influence at different times of day or different UV conditions (Bencala et al., 1988). Therefore, any conclusion regarding these concentrations when such fluctuations in the data exist are highly dubious.

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听听听听听听听Figure 5.5.1

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Iron is a difficult metal to evaluate against CDPHE Aquatic Life Standards due to its influence on water hardness and how it is calculated.听听But using the average water hardness value of 41 mg/L for the upper Snake River (Boyer et al., 1999) it is still possible to make a basic comparison that for most of the reach concentrations of iron exceeded the 1000ppb (ug/L) standard. However, as similarly observed with aluminum, the solubility of iron is particularly influenced by low pH.

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听听听听听听听听听听听Figure 5.5.2

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The largest discrepancy in mass loads between calculated and observed concentrations for all metals evaluated was with iron. The aforementioned dependence of iron solubility on pH is well demonstrated here by the near 50% reduction in mass load after the pristine inflow of Deer Creek. This subsequent loss of mass from the water column as precipitate could have been eventually remobilized by photochemical reactions that render ferrous iron back into its ferric state, which helps explain the variation and sources of error between calculated and actual loads.

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听听听听听听听Figure 5.5.3

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Lead

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Of all the metals evaluated for this project, lead showed one of the most stable concentrations observed throughout the reach. There were no great fluxes or excessive enrichment, but results did exhibit significant fluctuation in measurements between 9/22 and 9/29 at certain cites.

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Lead concentrations remained below CDPHE Aquatic Life Standards for nearly the entire reach, only spiking at Trib 2095 and remaining only slightly above the standard until after the conflux with Deer Creek. No mass loads were calculated due to the relatively small concentrations and high inherent sources of error due to data variability. Lead is perhaps the least harmful metal present in the upper Snake River in terms of concentration in relation to discharge, even though it has a low threshold for toxicity.

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听听听听听听听Figure 5.6.2

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听听听听听听听听听听听听Manganese did not display much variation in the data along the upper Snake. Tributaries were where the peak concentrations were observed, particularly at site 2095, which was 12x above baseline. This proved well above historical data levels and likely due to low flow conditions reducing dilution.听听听

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Manganese is difficult to evaluate against CDPHE Aquatic Life Standards due to its abundance as a mineral and taking into account how water hardness affects toxicity levels.听听By using a water hardness value of 41 mg/L for the upper Snake River (Boyer et al., 1999) the acute toxicity standard of manganese is 1556 ug/L. These levels are exceeded below Trib 2095 and remain so after the confluence with Deer Creek, though only slightly.

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听听听听听听Figure 5.7.2

Manganese showed very similar calculated and actual concentrations in terms of mass load. It indicates that precipitation could be occurring. However, it is also possible that uptake with sulfate,听听to render magnesium sulfate, could help explain this decrease.

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听听听听听听听Figure 5.7.3

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Zinc

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The levels of zinc measured throughout the upper Snake River are extremely high. Zinc presents a particular hazard in such high concentrations due to its intransigence to pH. Tributaries seemed to be a primary source; even in those tributaries such as Trib 915 that hinted that water chemistry was dominated by surface flows. Concentrations observed at Trib 2095 were a full order of magnitude above stream baseline levels, which results in a doubling of in-stream amount after its confluence with the upper Snake. Another 50% increase occurred between Site 2120 and SN-2, a trend similarly observed with copper and also perhaps due to flow through more mineralized material.

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听听听听听听Figure 5.8.1

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The necessary logarithmic scaling of measurements throughout the upper Snake River makes obvious the exceedingly high concentration of zinc present. Again using the 41 mg/L water hardness average (Boyer et al., 1999), we further see that zinc concentrations exceed acute toxicity levels for aquatic life by at least a full order of magnitude at each site in the reach. For Trib 2095 this proves to be a conservative estimate, as the results show concentration amounts up to two orders of magnitude beyond the standard. This nearly doubles the in-stream concentration below confluence with the Snake. Zinc is a metal of serious concern and a primary limitation in the stream in terms of biotic life. As zinc also demonstrates insensitivity to changes in pH in terms of solubility, this metal is being transported further downstream than any others observed, extending its threat well below the sampling area of this project.听

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听听听听听听听听听听听听Figure 5.8.2

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Here we see the intransigence of zinc to pH conditions demonstrated in the mass loads calculated and observed at site SN-2 and SN-3. Of particular interest is how these amounts are nearly identical, inferring that almost no precipitation is occurring and this metal load is remaining in solute well after the additional pristine inflow of Deer Creek. This exemplifies the dangers surrounding the presence of zinc in the water column, especially when accounting for its exceedance of toxicity standards. It also serves to explain why fish stocking is necessary to maintain fish populations; zinc loading at the headwaters of the upper Snake is implicit in making the stream largely uninhabitable.

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听听听听听听听Figure 5.8.3

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Chapter 6

Conclusions

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Sulfate

听听听听听听听听听听听听When comparing collected field observations of pH to levels of sulfate observed, a relationship was indicated between increasing concentrations of sulfate and reductions in pH. Both sampling days showed this trend, with high r2听values indicating significant correlation.

听听听听听听听听听听听听听听Figure 6.1

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听听听听听听听听听听听听The presence of sulfate is a proxy for pyrite weathering and the rendering of hydrogen ions. This provides additional insight into stream chemistry and dominant processes of metal enrichment occurring. Tributary 915, for example, demonstrated levels of sulfate (and pH conditions) slightly below the Snake River above its confluence, indicating groundwater sourcing. The observed lower temperature of this inflow further supports this hypothesis of groundwater sourcing. Other tributaries with high concentrations of sulfate had corresponding levels of iron, which is implicit in the weathering of pyrite-bearing minerals. However, a statistically valid correlation could not be established between iron and sulfate concentrations. This could be due to fluctuations in observed iron concentrations between 9/22 and 9/29 due to photochemical reactions and precipitate processes.

听听听听听听听听听听听听All sampled sites did show sulfate concentrations well above historical data, but it is difficult to say exactly what is the cause. It could reflect increased weathering, higher discharge values of the Upper Snake during mid-summer months, or decreased groundwater contributions due to falling water tables from reduced recharge. More recent data would provide greater insight into these changes, allowing for a more conclusive comparison.听听听听听听听听

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Metals

听听听听听听听听听听听听Metal concentrations did not unilaterally increase when compared to historical data. In the case of copper, the upper portions of the reach had significantly lower levels. For the reductions of copper observed at Trib 460, there were massive increases in other metal concentrations such as aluminum and iron.听听High sulfate concentrations further indicate that this is due to weathering byproducts.听听Trib 915, on the other hand, showed relatively smaller increases in these metals and drastic increases in copper. Trib 915 shows water chemistry characteristic close to those observed in the Snake, and temperature well below baseline; this suggests that lateral inflow has become the dominant source of water and helps explain the rise in copper concentrations. Since Trib 460 is at a higher elevation, a decreasing water table could have also reduced groundwater contributions to this particular stream. This is supported by a decrease in copper and a rise in metals that are more soluble at a low pH and is indicative of weathering processes. Increased concentration of copper at Trib 2095, a stream with high contributions of lateral inflow, as demonstrated in tracer testing by Caitlin Crouch and evident in observed low water temperatures on sampling days, provides additional evidence of copper and is indicative of groundwater processes.

听听听听听听听听听听听听Despite results showing metals at extremely high concentrations, such as aluminum and iron, throughout the upper Snake, concentration levels were reduced drastically upon the confluence with the pristine waters of Deer Creek.听听Zinc, on the other hand, with similarly high concentrations, remained in solute even after the confluence. This was demonstrated in the mass loads, highlighting both the intransigence of zinc towards pH changes in terms of solubility and the threat it presents to water quality further downstream.

听听听听听听听听听听听听The concentrations of zinc observed at SN-2 were high and well above average, though less than those taken in 2010. However, when the averaged data from 9/22 and 9/29 was added to the existing available record, a higher statistical correlation value resulted. This provides greater confidence in the findings of previous research that indicated an exponential increase of zinc concentration in the upper Snake River is occurring.听听听听

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听听听听听听听听听听听听听听听听听听听听听听听听听听听Figure 6.2

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Conditions

听听听听听听听听听听听听Dsicharges of the Snake River observed on 9/22 and 9/29 were nearly 40% below average than the 63 years of previously collected data. If trends in early snowmelt continue, coupled with increased warming in the Rocky Mountains and reductions in summer precipitation due to climate change, these flows may become the norm. Water table levels will drop accordingly, as they did in 2002, exposing more mineralized material to both weathering and oxidation. The transition from a linear to an exponential increase in zinc concentration observed appeared to be related to these periods of reduced flow, indicating for a future potential of even greater metal-enrichment in the upper Snake. As the river later confluences with Peru Creek, an AMD-impacted stream, this problem will only be enhanced.听听

听听听听听听听听听听听听As evident in observation from this project and those previous, groundwater contributions play a significant role in changing concentrations of certain metals. As recharge is reduced the water table is reduced, and some tributaries may become further dominated by ARD inflows. Massive increases in sulfate, aluminum, iron, and zinc in certain tributaries are already evidence of this when compared against historical data. Greater reductions in stream pH will play a role in rendering waters more soluble to metals and enhancing the transport of metals further downstream.

听听听听听听听听听听听听When observations from 2012 at Site SN-3 are included with the long-term yearly means from September, the frequency of anomalously low flow years appears to be increasing. If such trends continue, metal concentrations may exceed even exponential increases. The corresponding reductions in pristine inflows that currently serve to dilute these concentrations and neutralize low pH conditions will only serve to compound this.听听As a result, environments downstream that are currently marginal for aquatic life will become acutely toxic. This presents a unique challenge to resource managers and stakeholders who must maintain access to clean waters because the Snake River is already on the EPA 303(d) Impaired Waters list. Without the implementation of remediation strategies, currently hampered by outdated provisions of the Clean Water Act, the presence of metals in the Snake River will also remain 鈥渋n perpetuity鈥�.

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听听听听听听听听听听听听听听听听听听听Figure 6.3

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Presence of Rare Earth Metals

听听听听听听听听听听听听Thanks to the diligent work of Fred in the Laboratory for Environmental and Geologic Studies, the results of ICP-MS analysis show extremely high levels of rare earth metals in Trib 2095. Here the concentrations of听Samarium听,听Neodymium听, Uranium, Lanthanum,听Gadolinium,听Dysprosium, Erbium,听Praseodymium, and听Terbium were above an order of magnitude of those observed elsewhere in the reach. Considering the extremely low flows of this tributary, this is quite surprising. This site did not correspond with any know surveyed ore or mineral deposits in the area which would explain such high levels, making their occurrence all the more peculiar. As such rare earth metals are just as their name implies, the presence of them into a low-flow, high alpine stream is a topic that merits greater research. Tracer and isotope testing could possibly provide additional insight, as well as continued sampling of Trib 2095 to determine if these levels are rising.听

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Bencala, K., McKnight D., Zellweger, G., and B. A. Kimball. 1991.听Monitoring acidic streams for transport studies.听U.S. Geological Survey Toxic Substances Hydrology Program-Surface- Water Contamination鈥揚roc. of the Technical Meeting. G. E. Mallard, ed., U.S. Geol. Survey Open-File Rept. 87-764, 119-124.

Belanger, L (2002).听Source and Effect of Acid Rock Drainage in the Snake River Watershed, Summit County, Colorado.听M.S. Thesis. Department of Civil, Environmental, and Architectural Engineering, University of Colorado at 葫芦娃视频.

Bendiner, M. R. 1935.听Stream pollution and the disposal of waste. Editorial research reports 1935. Vol. II. Washington, D.C., United States: CQ Press.

Berwyn, B.听Fish kill in Snake River linked to Peru Creek. Summit County News.听Aug 9th, 2007.

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Boyer, E., McKnight D., Bencala K., Brooks P., Anthony M., Zellweger G., Harnish R. (1999)听Streamflow and Water Quality Characteristics for the Upper Snake River and Deer Creek Catchments in Summit County, Colorado: Water Years 1980 鈥� 1990, Occasional Paper No 57,听Institute of Arctic and Alpine Research, University of Colorado at 葫芦娃视频.

Clow, D. 2010. 鈥淐hanges in the timing of snowmelt and streamflow in Colorado: A response to recent warming鈥�.听Journal of Climate.听23(9), 2293-2306

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Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (Superfund). 42 U.S.C.听搂听9601. 96th United States Congress. 1980

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Colorado Department of Minerals and Geology, State of Colorado Department of Natural Resources. 2003.听Best Practice in Abandoned Mine Land Reclamation: The Remediation of Past Mine Activities.

Colorado Geological Survey.听听State of Colorado Department of Natural Resources. 1999.Abandoned Mine Land Inventory Project. In partnership with the U.S Forrest Service, Bureau of Land Management, U.S. Geological Survey. Data available through OSM Abandoned Mine Land Inventory System (e-AMLIS)

Colorado Department of Public Health and Environment. 2001. Regulation No. 31: Basic Standard and Methodologies for Surface Water

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Colorado Department of Public Health and Environment. 2005. Lefthand Creek Watershed Monitoring Data Report. CDPHE website, accessed May 1st, 2012.

Church, S. E., and Geological Survey. 2000.听Preliminary release of scientific reports on the acidic drainage in the Animas River watershed, San Juan County, Colorado. Open-file report. Vol. 00-034. Denver, Colo.: U.S. Dept. of the Interior, U.S. Geological Survey.

Crouch, C. (2011).听Impacts of Hydrologic Change on Geochemistry in the Upper Snake River, a High Mountain Acid Rock Drainage Stream.听M.S. Thesis. Environmental Studies Department, University of Colorado at 葫芦娃视频.

Dettinger, M. D. and Cayan, D. R.: 1995, 鈥淟arge-Scale Atmospheric Forcing of Recent Trends toward Early Snowmelt Runoff in California鈥�,听J. Climate听8, 606鈥�623.

Dexheimer, K. A., 1982,听Characterization of the trace metal geochemistry of the Dillon Reservoir and tributaries, Summit County, Colorado. M. S. Thesis, Department of Geological Sciences, Ohio State University.

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Environmental Protection Agency, 2003a. Lefthand Creek Watershed Case Study: Use of NPL as Catalyst for Abandoned Mine Cleanup. November 11, 2003.

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Environmental Protection Agency, 2003b. Region 8. Superfund: Captain Jack Mill Report.听EPA website, accessed April 28, 2012.

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Environmental Protection Agency. 2004. Lefthand Watershed Sampling and Analysis Plan. March 23rd, 2004.

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Forhardt, P.听听2003.听Water Quality From the Headwaters to the Plains.听Citizen Guide to Colorado Water Quality Protection,听2nd听Edition, Vol 7.

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Finley, B.听Risk of lawsuits threatening cleanup of abandoned mines in Colorado.Denver Post. Sept 9th, 2012

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General Mining Act of 1872. Sess. 2, Ch. 152, 17听Stat.听91鈥�96. 42nd United States Congress. 1872

Hazen, J.听听(2000).听Acid Mine Drainage Characterization and Remediation Using a Combination of Hydrometric Measurements, Isotopes, and Dissolved Solutes.听M.A. Thesis. Geography Dept., University of Colorado at 葫芦娃视频.

Kimball, B and the US Geological Survey.听Use of tracer injection and synoptic sampling to measure metal loading from acid mine drainage.听Report FS-245-96

Lovering, T. S., 1935,听Geology and ore deposits of the Montezuma Quadrangle, Colorado. US Geological Survey, Prof paper 178, 119p.

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McKnight, D., Crouch, C., Dunham, R., Manning, A., Todd, and A. Verplanck. 2012. 鈥淐limate-Change-Driven Deterioration of Water Quality in a Mineralized Stream鈥�. Joint study between the U.S. Geological Survey, INSTAAR, and EPA.听Environmental Science and Technology.听2012,听46听(17), 9324鈥�9332

McKnight, D., and Feder, G. 1984. 鈥淭he Ecological effects of acid conditions andprecipitation of hydrous metal oxides in a Rocky Mountain stream鈥�.Hydrobiologia听119:129-138.

McKnight, D., Kimball B., and Bencala K. 1988. Iron photoreduction and oxidation in an acidic mountain stream. Science 240, 637-640.

McKnight, D., Bencala, K. 1990. 鈥淭he chemistry of iron, aluminum, and dissolved organic material in 3 acid, metal-enriched mountain streams, as controlled by watershed and in-stream processes.鈥澨�Water Resource Res.听26 (12), 3087-3100.

Nash, J. Thomas, and US Geological Survey. 2000.听Geochemical studies of mines, dumps, and tailings as sources of contamination, Upper Animas River watershed, Colorado. Open-file report. Version 10 ed. Vol. 00-104. Denver, Colo.: U.S. Dept. of the Interior, U.S. Geological Survey.

Nordstrom, D. and the U.S. Geological Survey. 2009. 鈥淎cid Rock Drainage and Climate Change鈥�.听Journal of Geochemical Exploration.听v. 100, 97-104.

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Robinson, R S., Warner, L. A., and Wahlstrom, E. E., 1974,听General geology of the Harold D. Roberts Tunnel, Colorado. U. S. Geological Survey. Prof Paper 831-B, 48p.

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Rood, S., Pan, J., Gill, K., Franks, C., Samuelson, G., Shepherd, A. 2008. 鈥淒eclining summer flows of Rocky Mountain Rivers; changing seasonal hydrology and probable impacts on floodplain forests.鈥澨�Journal of Hydrology.听v. 349, p. 397-410

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Rood S., Samuelson G., Weber J., Wywrot, K. 2005 鈥淭wentieth-century decline in streamflows from the hydrographic apex of North America.鈥澨�Journal of Hydrology306:215-233.

Surface Mining Control and Reclamation Act of 1977 (SMCRA) 30 U.S.C.听搂听1234-1328. 95th United States Congress. 1977. Amended 1990, Abandoned Mine Land Reclamation Act (AMRA)

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Theobald, P., Lakin, H., Hawkins, D. 1963.听听鈥淧recipitation of Aluminum, Iron, and Manganese at the junction of Deer Creek with the Snake River in Summit County, Colorado.鈥澨�Geochimica et Cosrnochirnica Acta, 27, 121-132.

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Todd, A., McKnight, D., Duren, S., and 2005.听鈥淲ater Quality Characteristics for the Snake River, North Fork of the Snake River, Peru Creek, and Deer Creek in Summit County, Colorado: 2001 to 2002.鈥澨�Institute of Arctic and Alpine Research, University of Colorado at 葫芦娃视频. Occasional Paper 57.

United States Geological Survey. 1974. 7.5 Minute Series Topographic map, Montezuma Quandrangle. 1:24000.

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Biogas Emissions and Bioenergy Potential from a Palm Oil Mill Wastewater Treatment System in Southwestern Costa Rica,听Hana听Fancher听

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ABSTRACT

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The global awareness around sustainable products and practices has accelerated the support for research in developing applied solutions to contemporary climate and energy crises. Biogas capture and recycling technologies are a focus of renewable energy research efforts as they minimize climate change impacts and produce energy. The focus of this study was to quantify greenhouse gas emissions (GHGs), in particular methane, from palm oil mill wastewater and to evaluate the viability of using the emissions as a potential energy source at a palm oil mill in southwestern Costa Rica.

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INTRODUCTION

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Palm oil and palm oil derivatives have a wide variety of uses in products ranging from biodiesel, to soap, to margarine. Demand for palm oil across diverse commercial markets has led to rapid growth of the industry. Oil palm is also the highest yielding of all edible oil crops, producing up to ten times more oil per cultivated area than other major oilseed crops such as soybean and sunflower (Rupani听et al.听2010). High yield and high demand have made oil palm a very attractive cash crop, especially for developing nations throughout the tropics. However, rapid development has brought the sustainability of oil palm cultivation and oil production techniques into question.

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During the lifecycle of palm oil production, from oil palm cultivation to final palm oil product, there are many sources of waste. Palm oil extraction produces four main biomass waste groups: mesocarp fiber, shell, empty fruit bunches, and organic-rich wastewater鈥攑alm oil mill effluent (POME). Untreated POME is considered to be the most environmentally damaging waste product from palm oil production if it is untreated; not only will it eutrify any stream upon discharge, but POME emits large amounts of GHGs during the wastewater treatment process. POME makes up about 52% of the total waste by weight generated from palm oil mills (Rupani听et al.听2010) and yet it is the only type of mill waste that is not re-used by the industry. Approximately 5-7.5 tonnes of POME are produced for every 1 tonne of palm oil (Ahmad听et al.听2003), specifically the wastewater comes from three main sources along the oil extraction process: clarification (60%), sterilization (36%) and hydrocyclone (4%) units (Ma, 2000). Generally steam is used in each of these unit processes, which causes POME water to be very hot upon entering the wastewater treatment. Raw POME is a viscous, brownish liquid that is acidic and rich in proteins, lipids, and carbohydrates. Other common environmental features of POME are indicated in Table 1.

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Table听1

Typical characteristics of POME

Parameter	Value	Unit
Temperature	80-90	(掳颁)
pH	4.7	听
Chemical Oxygen Demand (COD)	50,000	mg/L
Total Suspended Solids (TSS)	18,000	mg/L
Total Volatile Solids (TVS)	34,000	mg/L
Oil and Grease	4,000	mg/L
Ammonia-Nitrate (NH3-N	35	mg/L
Total Kjeldahl nitrogen (TKN)	750	mg/L

Sources: Ma听et al.听(2000), Ahmad听et al.听听(2003), Rupani (2010)

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The conventional POME treatment method reduces the organic load prior to discharge into natural waterways through a series of open, gravity driven settling lagoons. The lagoon system has some advantages such as low capital cost, low maintenance and operating costs, high efficiency even under variable organic loading rates (OLRs), and reduced chemical oxygen demand (COD) concentrations by up to 97% (Yacob听et al.2006). Although there are advantages to using the lagoon system especially in terms of reducing COD, the lagoon system is a carbon hotspot and major biogas producer that has other disadvantages such as lengthy residence times and large land requirements,. Open lagoon systems utilize mostly anaerobic digestion to reduce the organic loads to a safely dischargeable concentration; however, the anaerobic process also releases large volumes of harmful GHGs鈥攃arbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).

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Methane has become central to climate change and renewable energy research. Methane is an extremely potent GHG having a warming effect 21 times that of carbon dioxide; however, methane can also be captured and used as a renewable energy source. This dichotomy of harmful versus helpful traits makes identifying sources of methane critical to combating climate change and exploiting renewable resources. For this reason methane is the focus of our research; however, CO2听and N2O are analyzed equally as all of the gases are needed to fully understand biogas production. Table 2 identifies typical feedstock sources of methane with corresponding organic concentrations represented via COD. 听

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Table听2 COD and methane emissions from various feedstock common in tropical regions
Feedstock Source	COD Range (g/L)	Average Methane Yield (m3/kg volatile solids)
Palm Oil Mill Effluent	50 鈥� 150	0.39
Pig Manure	30 鈥� 90	0.38
Dairy Manure	18 鈥� 48	0.24
Sugar Beat	1.5 鈥� 5.5	0.20
Municipal Solid Waste	15 鈥� 50	0.35
Sources: Lam and Lee听et al.听2011, Amon听et al.听2007, Chynoweth听et al.听1993, Forster-Carneiro听et al.听2007; Kabouris听et al.听2009, M酶ller听et al.听2004.

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There is a statistically significant and positive correlation between COD and average methane yield. Compared to typical feedstock in the tropics, POME contains among the highest concentrations of COD as well as a methane yield. The primary question motivating this research was, 鈥淐ould this methane yield be captured and transformed into a viable bioenergy or biofuel source?鈥� The goal of our research was to conduct an incubation experiment in order to measure biogas emission rates, patterns, and composition at a typical POME treatment system. Secondarily, we were interested in investigating the role of environmental and biogeochemical controls on the biogas production within our experiments. 听

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METHODS

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Study Site

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This research was conducted at a cooperative palm oil mill located in the Coto Sur Valley of southern Costa Rica (Figure 1). This area of Costa Rica receives an average of 350 mm/month of rainfall for eight months (April through November) of the year, and for the other four months (December through March) receives an average of 100 mm/month (The World Bank Group Climate Portal 2012). Although this may seem a dramatic precipitation difference, seasonal dilution effects have not been considered; the rational is as follows. Annual variability in precipitation may dilute POME by 3%-7%. In open lagoons systems, this seasonal difference in POME dilution by precipitation may cause small differences in biogas production rates. Luckily, the implementation of biogas capture would provide a solution for this issue since it would prevent the influx of precipitation.

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The oil mill refines fruits cultivated from surrounding oil palm plantations鈥攁pproximately 10,000 hectares鈥攑lacing it globally as a mid-sized mill. The mill produces approximately 300 tonnes of crude palm oil (CPO) per day from 2000 tonnes of fresh fruit bunches (FFB). Unlike many of the other oil mills in Costa Rica, our particular site further refines the CPO into other commercial palm oil derivatives such as margarine. As a by-product of palm oil production, the mill generates 1000 cubic meters of organic-rich wastewater each day, which is piped 0.75 km to the effluent treatment lagoons.

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Figure听1

POME Treatment System听

Sources: Google Earth

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The effluent treatment system is comprised of 13 gravity-fed lagoons connected by a network of concrete lined channels (Figure 1). The system utilizes eight descending elevation levels to drive the flow path, generally having one set of parallel lagoons per elevation level (Figure 1). The total area of the treatment lagoons is approximately 0.03 km2听and the average depth of the treatment lagoons is 3m. Each individual lagoon is at least the size of one-half of a soccer field. The treatment system has a retention time of 50 days. POME treatment begins in cooling lagoons 1.1 and 1.2; Figure 1, and continues (following numerical labeling scheme) through a series of settling lagoons (Figure 1). Along the earlier stages of the flow path, the particulate matter begins to settle and accumulate on the base of lagoons 1.1-4; however, after lagoon 4, all fine sediment has settled out. At the outlet of lagoon 8 the COD of the POME has been reduced to a regulatory standard of 300 mg/L or below and is discharged into a stream adjacent to the treatment complex. To promote COD removal, the palm oil mill operators periodically add slurries of yeast and molasses in the channel between treatment lagoons 1.2 and 2.1 (Figure 1).

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Sample Collection

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We collected samples from treatment lagoons 1-6 and 8 on February 29, March 1, and March 2, 2012. We used a sampling rod fashioned out of 3m x 15cm PVC pipe to collect sediment and water samples. In order to capture the spatial variability within treatment lagoons, we collected composite samples of sediment and water from multiple locations within a lagoon and duplicate lagoons when applicable (e.g., lagoons 1.1 and 1.2). Sediment-water slurries were strained through a 263碌m sieve into a bucket, and material left in the sieve was homogenized and then used as sediment for the incubation experiments. We preserved aliquots of sediment on ice in the field for downstream analyses. Thereafter sediments were frozen at -20掳C. Sub-samples of lagoon water were filtered at 0.22碌m in the field immediately after collection, and were stored at 4掳C.

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Incubation Preparation

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We performed two types of incubation experiments: water-only incubations and sediment-water incubations. To constrain fluxes of CH4, CO2听and N2O from POME lagoons each day (three days) we conducted four replicates per incubation type, per lagoon. At the end of the study, 132 incubation experiments had been performed. Water-only incubations were prepared by adding approximately 60ml of the composite water samples to four replicate 125ml glass serum vials. To prepare the sediment-slurry incubations we added an average of 18g of homogenized sediment to four replicate incubation vials, and then we added 60ml of the composite water samples. After anaerobically sealing each vial, we purged the sample with dinitrogen (N2) gas for 2 minutes at 4psi in order to purge incubations of any remaining oxygen in the water or headspace.

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Gas sampling

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We sampled the headspaces of each incubation vial at four time intervals over the course of nine hours. We collected the first sample of headspace gas 30 minutes after the conclusion of flushing the headspace with N2听gas (sampling time point听t0). Our next headspace samples were collected 3.5hrs, 6hrs and 9hrs after听t0. We inserted each headspace gas sample into 20ml serum vials flushed with ultrahigh purity, helium-flushed sealed with butyl rubber stoppers (Bellco Glass, Vineland, NJ, USA). Over the course of 3 days, we collected headspace gas samples at four time points for each of the 132 incubation vials; approximately 528 gas samples were transported back to the University of Colorado for analysis.

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Gas Analysis

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We used a gas chromatograph (GC) equipped with a thermal conductivity detector, an electron capture detector, and a flame ionization detector to analyze concentrations of CH4, CO2听and N2O in sample vials (Shimadzu Scientific Instruments, Columbia, MD, USA). CH4, CO2听and N2O flux rates were calculated for each incubation vial over time points 0 and 6; we saw no increase in concentration after听t6听so fluxes were only calculated using the first three data time points (t0, t3.5, t6); the nine hour time point was not included in the analysis. Further discussion of the gas concentration plateau after听t6听is provided in the results section.

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Aqueous Chemistry

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The chemical oxygen demand (COD) of water samples collected from lagoons 1-6 and 8 was determined using Hach Method 8000鈥擲tandard U.S. EPA Reactor Digestion method adopted from Standard Methods for the Examination of Water and Wastewater. The total suspended solids (TSS) of water samples were determined in accordance to methodology outlines in Standard Methods for the Examination of Water and Wastewater, (Eaton 2005). The total dissolved organic carbon and total dissolved nitrogen in lagoon samples were analyzed on a Shimadzu TOC-V CSN Total Organic Carbon Analyzer, and nitrate concentrations were determined with a Lachat QuikChem 8500 Flow Injection Analyzer at the Kiowa Environmental Chemistry Laboratory at the University of Colorado.

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Gas Data analyses

Gas fluxes were determined from the Shimadzu analyzed concentration data for听t0, t3.5,and听t6听samples. Detected gas concentrations were determined using the following equation:

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听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听听Equation 1

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Variable: Equation 1	unit
Mass of gas present	kg
Mass of incubated POME slurry	g
(Concentration of gas)/(headspace injection)	ppm = mg/kg
(Molar mass of gas)/(molar volume of ideal gas)	kg/m3
Volume of incubation bottle headspace	m3
He dilution	3

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Fluxes were calculated for each incubation vial based on linear regression trends. Final听t9data points were not included in the flux calculations because our data analysis demonstrated that there was no increase in headspace gas concentrations between听t6and听t9. Then, the linear regression slope between t0, t3.5, and t6, was used to calculate the gas flux. Fluxes each incubation bottle were then assembled into groups based on corresponding lagoon location and incubation type (e.g. 7 groups for water incubation data, 4 groups from sediment-water incubation data). Any negative production fluxes were then removed from the group (eight fluxes were negative and removed from the group), followed by group mean calculations (碌) and standard deviation calculations (蟽), and the calculation of outliers +/- 2蟽 of the mean. Using Matlab box and whicker Figures A- F were assembled to display group distribution. Outliers are represented as red crosses, the box encompasses data from the 25th听and 75th听percentiles, and the whiskers extend to the data points not considered outliers.

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3.0 Results

Environmental Conditions

In order to understanding the mechanisms, recognize patterns, and investigate controls on biogas production we analyzed the biogeochemical parameters in Table 3.

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Table听3

Environmental conditions of POME perLagoon	D.O.	pH	Temperature (掳颁)	TSS (mg/L)	COD (mg/L)	DOC (mg C/L)	TDN (mg N/L)	NO3-+NO2-(mg N/L)
1	0.27	4.47	42.75	172900	32173	4319.52	80.65	0.13
2	0.44	6.02	34.80	25900	74226	2063.33	80.14	0.09
3	0.32	7.10	33.93	25340	26339	1475.67	121.50	0.05
4	0.21	7.19	34.20	11200	7679	1321.23	109.26	0.04
5	0.20	7.75	34.95	681	677	1432.91	113.34	0.31
6	0.31	7.68	31.95	791	672	1314.58	109.84	0.63
7	0.21	7.82	30.80	565	299	1541.19	28.92	0.61

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As expected, temperature, TSS, COD, DOC, and TDN all display descending trends as POME settles and is organic degraded along the treatment system. The alkalinity moves from an acidic influent POME to a neutral discharge. The anaerobic condition of the lagoons is confirmed with dissolved oxygen measurements well below 1.0 (mg/L). For the organic matter to be fully degraded to methane there are several different and important metabolisms at play, all of which are sensitive to available substrates, DO, pH and temperature. In hydrolysis, the first step in organic degradation, lipids, carbohydrates, and proteins substrates are converted into alcohols, fatty acids, amino acids and sugars. During hydrolysis no mineralization of organics occurs so there is no reduction in COD, Eckenfelder (1989). It is likely hydrolysis is occurring in lagoons 1 and 2, and the spike in COD is a result of the addition of yeast and molasses between lagoons 1 and 2 in the connection channel. The yeast and molasses addition is done to increase the rate of the hydrolysis reactions.

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Also in lagoon 2 it is probable that the next phase of degradation is occurring; acidogenesis. The fermented bacteria (i.e. added yeast) absorb the hydrolysis products and in turn produce a variety of by-products depending on the starting substrate. Most desirable for methanogens is the production of acetic acidic, but a large portion of fermenters also produce carbon dioxide. Based on site observation and figure 3, lagoon 2 has the highest rate of CO2听production and fermenting occurring. It is important to note that with such a large volume and slow flow rate it is possible to have multiple pathways coexisting such as hydrolyzing organisms and acidogenesis coexisting. Having the coexistence of multiple organisms in one lagoon is a problem that leads lagoon 2 to the most productive lagoon in the system. To account for the large percentage of methane being released from lagoon two and beyond methanogenisis must be occurring.听

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The final step in methanogenisis is the conversion of acetogens by-products to methane. Some bacteria will utilize the organic products such as propanol, butanol, acetate, H2and sometimes CO2听to create methane. This step is happening in all lagoons but primarily between lagoons 2 and 4. This leaves lagoons 5-8 for speculation as to what processes are occurring in the later lagoons. As the dramatic drop in methane coincides with a relative leveling of COD reduction, perhaps the majority of preferable substrate has been used up by the time the POME makes it into lagoon 5.

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Magnitude and variation in biogas emissions across the lagoons

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Figures 2 and 3 show biogas emission rates and compositions for the lagoon system, each of which is comprised of 2 types of incubation data. Fig 2 A-C and Fig 3 A represent data collected from lagoon sediment-water incubations; Fig 2 D-F and Fig 3 B represent data collected from lagoon water-only incubations. Lagoons 2 and 3 were found to be the largest producers of biogas. Maximum biogas production occurred in lagoon 2 sediment-water incubations at approximately 0.50 (mg) of CH4听per incubated slurry (g) per day (Fig. 2 A). Carbon dioxide rates also peaked in lagoon 2 sediment-water incubations with an average production of 0.63 (mg) CO2听per incubated slurry (g) per day (Fig 2B). The production rate of both methane and carbon dioxide begins to decline after lagoon 2; however, in lagoon 3 of the sediment-water incubations, the majority of the biogas mixture emitted is comprised of methane with 64% (Fig 4). This is the only lagoon (for either incubation method) in which methane content dominates carbon dioxide.听听听

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Figure听2

Gas fluxes per lagoon, A-C represent data collected from lagoon sediment-water incubations; D-F represent data collected from lagoon water incubations only

The average composition of methane gas found for the system was approximately 39% and ranged from 2% to 65% across lagoons. The average composition is similar to the findings of Yacob听et al.听and Shirai 2003; however, both of these studies were performed on open digestions tanks rather than open lagoons: open digestion tanks are the most analogous treatment system to open lagoons. Commonly referenced studies of Yacob et al. (2005), Ma听et al.听(1999) and Quah and 听Gillies (1984) indicate typical methane content of digested POME to be nearly 50%-65%, much of the variability among methane compositions can be attributed to differences in digester type, environmental conditions, chemical properties of POME, and variability in experimental controls (lab versus in-situ studies).

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Figure听3

Gas flux compositions per lagoon. Figure 3A represents data from

sediment-water incubations and Figure 3B represent water only incubations

Figure听4

Gas flux composition and Carbon dioxide

听equivalence across the system.

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A commonly used parameter for estimating methane emissions is COD. Table 3 shows COD concentrations per lagoon. The untreated, or raw POME, enters the treatment system with a COD of ~32,000 (mg/L), typical raw POME can have a COD as high as 80,000 (mg/L) and on average is approximately 50,000 (mg/L) (Yacob 2005). The average maximum COD of 74,226 (mg/L) was found in Lagoon 2. The highest emission rate is also found in Lagoon 2. The coinciding correlation between methane generation and maximum COD is expected and can be attributed to environment and microbial conditions.听 The average methane emitted per lagoon per day is approximately 2,000 kg. Table 3 also displays the biogeochemical characteristics of POME, which strongly determine the rate and composition of biogas emitted.

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DISCUSSION

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In this study we found that magnitudes of biogas rates and compositions vary along the flow path. General trends of emission flux data and composition data demonstrated the lagoon system to be front-loaded: the majority of biogas activity and successive substrate degradation occurred in the first half of the treatment process, suggesting that the microbial communities, quantity, and types of substrates present are crucial to the successful digestion of organic matter and biogas production. We determined an average methane composition of 39% comparable to that of Yacob (2006) and Shirai (2003) with 36%. However 39% is lower than an anticipated 50-60%, and significantly lower than the 65% conversion factor adopted by Clean Development Mechanism (CDM) projects (Chong and Philip 2001). This is especially worth noting since CDM projects typically tend to be conservative. The 65% methane concentration has been established using data generated from studies mostly of open tank controlled bioreactor experiments such as in (Ma听el al.听1999). Numerous factors have been identified as contributing to this discrepancy between industry estimation and actual measurements: variability in quality and quantity of influent POME due to mill operations, oxygen exposure, pH variation, volatile fatty acids concentration, addition of fermented microbes pushing composition towards CO2, and accuracy of lab versus in-situ measurements.

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Despite the discrepancy in gas composition, the biogas production rates we measured indicate high bioenergy potential (Table 4). Presently, biomethane is being emitted into atmosphere, rather than being recycled and used for renewable energy. In an effort to predict the bioenergy potential of the lagoon systems, should these gases be captured calculations, Equations 2 and 3, as well as CDM conversion factors were used to quantify annual methane flux:

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Equation听2

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Equation 3

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Parameters: Equations 2 & 3	unit
Gas emission flux / pond*day	kg/pond*day
听Incubated gas flux/ incubated POME slurry	mg/g/day
Total POME per pond Power Potential Est. CH4听emitted/system Density of听 to kWh (adopted from CDM projects for a methane fermentation capture system) Composition correction (*CDM assumes a methane composition of 65%, our data produced an average of 39%)	g/pond kWh see Table 5 0.66 kg/m3 2.77 MWh/m3 听

Source: 鈥淓ngineering Toolbox鈥�,听 (Shirai听et al.听2003).

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Some assumptions made in order to apply the CDM conversion of听volume of methane to kilo-watt hours: we assumed our system to be mid-sized and capable of producing 65,000 tonnes of CPO per year. Second, in order for estimates of possible power generation to be made, a closed fermentation system capable of capturing methane must be chosen to replace the existing lagoon system鈥攐therwise no gas will be captured. In this scenario we choose to estimate power production of the system as if the lagoons were replaced with a series of large, closed-tank digesters. Final estimates yielded a potential annual power production range of (11*106听听kWh/year)听 to (16 *106听听kWh/year) from this site alone. This is equivalent to 1-2 power stations capable of producing 500 kW (Shirai听et al. 2003).

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Table听4

Estimations: Biogas emissions and power potential

Biogas Emission Estimations	Water incubation	Sediment/water incubation
Average CH4听emission rate (per lagoon)	1821 kg/day	4560 kg/day
Average CO2听emission rate (per lagoon)	2423 kg/day	4926 kg/day
Estimated CH4听emitted (from听system)	12750 kg/day	18242 kg/day
Estimated CO2听emitted (from听system)	16963 kg/day	19703 kg/day
Total CO2听equivalent emitted (from听system) Total potential power generated per year (fromsystem)	284712 kg/day 听 11*106听kWh/year	402794 kg/day 听 16*106听kWh/year

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CONCLUSION

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This study validated the quantity and composition of greenhouse gases being emitted from palm oil wastewater lagoons. The importance of this research is that it will not only increase awareness of untapped energy sources, but it will also hopefully bring applied solutions to other similar situations. Biogas reactors in particular are uniquely beneficial compared to other environmental technologies because of their ability to convert a harmful pollutant into a beneficial energy source. Latin American palm oil plantations and mills soon will need to find energy solutions to become more sustainable to address growing public concerns about the environmental problems of the industry. Costa Rica has recently taken a pledge to become carbon neutral by 2020; POME biogas is an opportunity that could help accelerate this goal. We show that a POME biogas capture system would yield high bioenergy, bringing local socioeconomic and environmental benefits, as well as an overall more sustainable industry. It is important with industries such as palm oil, which are rapidly increasing and do not show signs of slowing, that research and infrastructure be put in place to help them responsibly grow.

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Authors Note:

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Thank you to all professors, friends, and mentors I have had for the past two years of this projects鈥攖he experience has changed my life.

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