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Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Razorback Sucker and Humpback Chub in the Colorado River Abstract The Colorado River has been called the lifeline of the Southwest United States because it provides water and electricity to over 25 million people. In fact, a body of laws collectively referred to as the “Law of the River” allowed the development of the Southwest because it promoted use of the Colorado River water for industry, agriculture, and human needs. However, the creators of the “Law of the River” didn’t consider what impact water development (e.g., building of dams, channels, etc.) would have on the native fish in the river. Dams built on the Colorado River changed a number of habitat conditions, including decreasing temperature, interrupting natural flow regimes, and reducing turbidity. These alterations were a problem for native fish as they were better suited to live in pre-dam conditions. Although habitat alteration was a big problem for native fish, introductions of non-native fish species to the Colorado River were also problematic. Non-native fish are efficient predators on the eggs and young of native fish and have virtually eliminated younger age classes from populations of native fish. With little suitable habitat and predation of non-native fish, species like the Razorback Sucker and Humpback Chub, are in a dire situation. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Description of Conservation Issue Razorback Sucker and Humpback Chub are both endangered species in the Colorado River Basin. The main causes of these species’ decline are habitat alterations and non-native species introductions (U.S. Fish and Wildlife Service 2000). There are two inherent conflicts in this situation: (1) How do humans use more Colorado River water for economic development and their daily needs while still maintaining water levels and flows for endangered fish species? (2) How do state and federal wildlife agencies protect these endangered species while simultaneously stocking non-native fish to enhance sports fisheries in the Colorado River Basin? Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Historic Conditions The Colorado River was an unobstructed system that flowed freely for over 1,400 miles. Its headwaters in the Rocky Mountains of Wyoming provided for large flooding events and a siltation of the river in the spring after snowmelt. These large flooding events carved out shallow sections of river that provided spawning habitat for many of the thirty-six native species of fish that historically lived in the Colorado River system. The silt carried by the river inspired the first Spanish explorers to call it “Rio-Colorado” or Red River (Gelt, 1997). The river was also much warmer than it is today without the influence of the cooling effects of hydroelectric dams. Learn More Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness In the 1800s Private citizens, state, and federal wildlife agencies began stocking non-native fish species into the Colorado River to enhance sports fisheries. They stocked flathead catfish, largemouth bass, bluegill, green sunfish, trout, and many other fish species into the Colorado River system. Currently, there are forty species of non-native fish in the Colorado River. The number of introduced fish species (40) outnumbers the number of native fish species, those that originally lived there. Native fish species numbers declined dramatically after the introductions of non-native fish species because non-native fish were efficient predators of the native species’ young and eggs (U.S. Fish and Wildlife Service 2002). Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness In the 1900s States in the Colorado River Basin had many disputes over who had rights over the water in the Colorado River. Each state wanted to establish its own limits on use of Colorado River water. A body of interstate compacts, federal laws, water contracts, state laws, a treaty with Mexico, Supreme Court decrees, and Federal and State administrative actions were developed to resolve these differences. These laws are collectively referred to as the “Law of the River” and have been very instrumental in the development of the Southwest United States. The Hydroelectric Dams provide water and electricity to industry, agriculture, and over 25 million people living in the Colorado River Basin states (Gelt, 1997). Although these laws were successful in developing the Southwest, they were also detrimental to native fish species living in the river. Habitat conditions changed rapidly with the closing of the gates of the Glen Canyon Dam in 1963. Almost immediately, water temperatures dropped, flow was interrupted, and silt began being trapped by the dam. As the habitat in the river changed from a system to which native fish were well adapted to a system to which they were not well suited, native fish populations started to decline. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Present Conditions The Colorado River today is a reflection of what the “Law of the River” and the humans who created that body of legislation wanted it to be. It is a series of connected reservoirs blocked by hydroelectric dams for the use of humans. These dams have been beneficial for the development of the Southwest, but have changed the habitat conditions in the river. Now the river is clear and cool; there are few flooding events in the spring (beneficial for spawning habitats); and there is erratic flow the rest of the year. The river also provides great opportunities for sportsman to go fishing for many game fish species, even though most of them are not native to the system. Endangered Species in the system still face the danger of going extinct without action from State and Federal wildlife agencies The Colorado River is vastly different than it was before the influence of man, and this change is a direct result of the history of human interaction with the river. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Relevant Research There is a lot of research that has been conducted on the endangered species of the Colorado River. What is striking about all this research is that it is very consistent as to the cause of the declines of Humpback Chub and Razorback Sucker. It seems that every piece of scientific evidence we have on the Humpback Chub and Razorback Sucker point to the same challenges of habitat destruction caused by water development and predation by non-native fish species. The next few slides provide a study-by-study synopsis of the challenges these species face as defined by research: Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Life History and Ecology of the Humpback Chub in the Little Colorado and Colorado Rivers of the Grand Canyon By: LYNN R. KAEDING AND MARIAN A. ZIMMERMAN Synopsis: This study shows that the only viable population of Humpback Chub lives in the Little Colorado, which is a shallow and warm tributary of the Colorado River. This tributary is protected from predators because it is too shallow for them to live there. This study also shows that the cold temperatures in the Colorado River cause nearly complete mortality of embryonic and larval Humpback Chubs. The researchers of this study suggest that the Little Colorado be protected from species introductions as it is the only place that Humpback Chub can reproduce and devastating effects could result from these introductions. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Predation by Introduced Fishes on Endangered Humpback Chub and Other Native Species in the Little Colorado River, Arizona By: PAUL C. MARSH AND MICHAEL E. DOUGLAS Synopsis: This study showed that native fish species represent a significant percentage of introduced species’ diets. More specifically, this study sampled rainbow trout, channel catfish, yellow bullhead, black bullhead, and brown trout diets in the Colorado River. Researchers found that native fish species represented thirty percent of these fish’s diets. Three percent of these diets were comprised of Humpback Chub. The researchers calculated that each the predator fish they sampled eat an average of 2.3 Humpback Chubs per week. This means that 1,000 predators will consume around 4,000 Chubs annually. This predation represents a major negative effect on the population. Researchers also pointed out the fact that juveniles represented a large portion of the Humpback Chubs consumed. This study shows how non-native predation not only limits recruitment, but also decreases the total adult population and reproduction from such. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Ecology of Spawning Humpback Chub, Gila Cypha, in the Colorado River near Grand Canyon, Arizona By: OWEN T. GORMAN AND DENNIS M. STONE Synopsis: This study describes the spawning activity of Humpback Chub in the Colorado River. Researchers found that Humpback Chub spawning activity was correlated with peak flows in April and also with higher temperatures found in tributaries, such as the Little Colorado River. They stress that temperatures in the Colorado River do not typically get warm enough to induce spawning activity of Humpback Chub. They also state that spawning sites were correlated with the structural complexity found in the tributaries of the Colorado River. The researchers state that since flooding events no longer occur in the Colorado River, there are no forces to carve out the shallow spawning pools on the banks of the river that provide the structural complexity Humpback Chubs use to spawn. This study also provides evidence for spawning migrations of adult Humpback Chub that live in the Colorado River approximately 13 kilometers up the Little Colorado River. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Effects of a Test Flood on Fishes of the Colorado River in Grand Canyon, Arizona By: RICHARD A. VALDEZ, TIMOTHY L. HOFFNAGLE, CAROLE C. MCIVOR, TED MCKINNEY, AND WILLIAM C. LEIBFRIED Synopsis: This study looked at the effects of an experimental test flood on the Humpback Chubs species in the Colorado River. Researchers found that Humpback Chub and native fish species had good spawning success in the slack water pools created by the flood, but had little overall impact on the survival of non-native fish species. The flood displaced these species, but they came back after eight months. The conclusion of this study is that floods may serve to temporarily reduce non-native species competition with native fish species, but a flood of many more orders of magnitude would be required to reduce non-native fish substantially. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Population Status of the Razorback Sucker in the Middle Green River (U.S.A.) By: TIMOTHY MODDE, KENNETH P. BURNHAM, AND EDMUND J. WICK Synopsis: The results of this study were that the Razorback Sucker are able to reproduce during high flow years, but these flows are reduced greatly by the influence of dams. Floods are essential to Razorback Sucker reproduction because they use the shallow water habitat caused by overbank flooding to reproduce. This study shows that there is positive recruitment during high flow years, which reinforces that flooded bottomlands on the Colorado River are important for reproduction. This study also emphasizes that the increase in introduced fish species populations is closely associated with the decrease in Razorback Sucker populations. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Relative Sensitivity of Three Endangered Fishes — Colorado Squawfish, Bonytail, and Razorback Sucker — to Selected Metal Pollutants By: KEVIN J. BUHL Synopsis: This study looked at metal pollution concentrations and its effect on Razorback Sucker populations. The researchers found that most EPA regulations on metal pollution were adequate or had no effect on the Razorback Sucker. They also found that cadmium was an important metal that has strong implications on Razorback Sucker because it greatly reduced their ability to reproduce. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Geomorphology and Endangered Fish Habitats of the Upper Colorado River 1. Historic changes in streamflow, sediment load, and channel morphology By: MARK M VAN STEETER AND JOHN PITLICK Synopsis: The results of this study showed that peak discharges have decreased 19 – 38% and that annual sediment loads have decreased 40 – 65% in the Colorado River. It also states that the main channel of the Colorado River has narrowed an average of twenty meters, which means that 25% of the area formed by side channels and backwaters has been lost. All of these changes in the habitat are related to reduced and restricted water flow in the river. This reduced flow caused by dams has effectively reduced the heterogeneity of the habitat used for spawning by native fish species in the Colorado River. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Habitat Use by Hatchery-Reared Adult Razorback Suckers Released into the Lower Colorado River, California–Arizona By: RICHARD H. BRADFORD AND SCOTT D. GURTIN Synopsis: This study looked at the habitat use by hatchery-reared Razorback Suckers. The results of this study were that backwater habitats were used the most often among hatchery-reared Razorback. The second-most important habitat used by Razorbacks was side channel habitats. Main channel habitats were rarely used by this fish species. Researchers emphasize the need to protect backwater and side water habitats for Razorback Suckers. They also make recommendations for stocking of Razorback Sucker in areas that provide a suitable amount of backwater and side channel habitats. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Conflicts And Debate The stakeholders of the Colorado River are vast as there are a number of private citizen organizations in addition to state and federal agencies involved. On the governmental side, you have Colorado River Basin States fish and game departments, Colorado River Basin States EPA’s and legislative bodies, the United States Fish and Wildlife Service, the Army Corps of Engineers, and the United States Environmental Protection Agency. On the other side, you have private citizens, private citizen organizations, agricultural operations, industry, and mining operations. Neither side totally agrees on what needs to be done with the river to benefit such native fish species as the Humpback Chub or Razorback Sucker. The two basic conflicts between many of these groups are: (1) One side wants to protect native fish species by restoring habitat conditions that are beneficial to these fish while another side would like to use more water or develop land and degrade habitat further to provide for some facet of human need and (2) One side likes fishing for game species in the Colorado River System, but the other realizes that these species have eliminated reproduction of native fish species and have caused their decline and therefore, this agency or group is for the removal of non-native fish or at least the elimination of stocking non-native fish. Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Relevant Legislation There are four relevant laws that apply to endangered species in the Colorado River Basin: • The Mining Law of 1872 • Water Law • Clean Water Act • Endangered Species Act Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness The Mining Law of 1872 The price for metals is increasing and many multinational companies are looking to make mining claims on Federal lands near the Colorado River. Most companies want to stake a claim on these Federal lands for the rich uranium deposits that are found near the Colorado River. Even though the Colorado River supplies drinking water for over 25 million people, there is little protection to stop mining because the Mining Law of 1872 allows all citizens of the US to locate hard rock or gravel and claim it for mining (EWG, 2008a). These minerals include, but are not limited to, platinum, gold, silver, copper, lead, zinc, tungsten, and uranium. The EPA has reported that mining has contaminated the headwaters of more than 40 percent of Western watersheds. Furthermore, the Environmental Protection Agency has identified metal mining as the nation’s leading source of toxic pollution for nine consecutive years (EWG, 2008b). With metal prices on the rise, it is likely that these mines will be opened and cause contamination of the Colorado River. This contamination could have strong negative impacts on fish health in the river. Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Water Law Most water law is formed by disputes between people who want to use the water for some purpose. The Western United States uses prior appropriation in which the first person to use water for a “beneficial use” has rights over the water to limit these disputes. In fact, the “Law of the River” was formed because of disputes over water usage among the states in the Colorado River Basin. While each law of “The Law of the River” individually has some effect on the Humpback Chub and Razorback Sucker, for the purpose of this discussion we’ll focus on some of the most important legislation and briefly discuss what the other laws in the “Law of the River” were meant to accomplish. Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness The Law of the River The foundation for the “Law of the River” was the Colorado River Compact of 1922 (Gelt 1997). This Compact divided the Colorado River Basin into Upper and Lower Basins with the dividing line at Lee’s Ferry, Arizona. The upper states were apportioned 7.5 million acre feet of flow, and the lower basin was apportioned the same amount of flow with the option of using an additional 1 million acre feet of flow. The problem is that legislatures apportioned more water for use by the states than what actually flows through the river. Basically, all water is apportioned for use by the states and no water is left for fish species habitat. The Boulder Canyon Project Act of 1928 and the Colorado River Storage Project Act of 1956 authorized the building of the Glen Canyon Dam, the Hoover Dam, and several other dams for hydroelectric power and flood control (Gelt 1997). These Acts also had provisions for how water was going to be used for economic development of the region and put to a “beneficial use” for humans. The other laws that form the “Law of the River” dealt specifically with how water was going to be used between states, the U.S. and Mexico, and people within the states. These laws also focused on how to use the water toward development and “beneficial use” by humans. Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Clean Water Act Section 101(a) of the Federal Water Pollution Control Act (i.e., Clean Water Act; 33 U.S.C. 1251–13287) states that the objective of this law is to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters and provide the means to assure the “...protection and propagation of fish, shellfish, and wildlife... .” This statute contributes in a significant way to the protection of the Razorback Sucker and Humpback Chub and their food supply through provisions for water quality standards — protection from the discharge of harmful pollutants, contaminants [Section 303(c), Section 304(a), and Section 402] and discharge of dredge or fill material into all waters, including certain wetlands (Section 404) (U.S. Fish and Wildlife Service 2002). Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Endangered Species Act The primary regulatory mechanism for protection of the Razorback Sucker and Humpback Chub is through Section 7(a)(2) of the Endangered Species Act (ESA), which states that “Each Federal agency shall, in consultation with and with the assistance of the Secretary, insure that any action authorized, funded, or carried out by such agency... is not likely to jeopardize the continued existence of any endangered species or threatened species or result in the destruction or adverse modification of habitat of such species which is determined by the Secretary, after consultation as appropriate with affected States, to be critical...” (U.S. Fish and Wildlife Service 2002). Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Endangered Species Act (Continued) The Upper Colorado River Basin Recovery Program (UCRRP) provides a mechanism for dealing with Section 7 consultations. There are currently no formal recovery programs in the lower basin, and Section 7 consultations are addressed on a case-by-case basis (U.S. Fish and Wildlife Service 2002) . None of the recovery or conservation programs in the Colorado River Basin are regulatory mechanisms that provide permanent, long-term protection for the species after delisting. In addition to Federal protection under the ESA, Razorback Suckers and Humpback Chub are protected by all basin States under categories such as “endangered,” “threatened,” or “sensitive.” This protection prohibits intentional take-and-keeping or harming in any way any fish captured incidentally, and may need to remain in place after the species is delisted (U.S. Fish and Wildlife Service 2002). Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Effectiveness of the Endangered Species Act The Endangered Species Act has been a good thing for the Razorback Sucker and Humpback Chub in the Colorado River. Many of the studies mentioned as contributing toward the management of these endangered species were funded through ESA provisions. These studies depended on ESA money to fund their research, but the ESA depends on them to make the appropriate decisions when designating critical habitat under Section 7 of the ESA. Critical habitat designations have allowed for protection from habitat modifications that threaten these fish species, but also from the stocking of non-native fish species and, in some instances, the removal of non-native fish species from these areas. It also protects these species from being taken from the river through fishing or other means. Without the ESA, the Razorback Sucker and Humpback Chub may very well have gone extinct. Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Problems with the ESA While the ESA is important for the protection of the Humpback Chub and Razorback Sucker, the legislation itself can only go so far to protect and enhance the Colorado River for these fish species. ESA decisions are based on best biological information, but as most fisheries biologists know, much of fisheries conservation is socioeconomic or political (Minckley, 2003). As is the case on the Colorado River — many factors other than biology influence most plans and projects for the conservation of these native fish. These factors contribute to reducing the benefit of the ESA to the species of concern. Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Problems with the ESA (continued) The US Fish and Wildlife service is supposed to enforce ESA regulations and promote sport fishing, but it has trouble balancing these conflicting interests. There is an inherent conflict between the management of non-native sport fish and recovery of endangered fishes. Where valued sport fisheries occur, there is an ongoing dilemma between public demands for maintenance and expansion of fisheries and management actions to conserve and recover endangered fish (Minckley, 2003). State agencies have the same problem on the Colorado River, trying to balance private citizen and companies’ interest with the biological integrity of the system. Unfortunately, much of the time private citizen and companies who represent much of the support for state and federal wildlife agencies win out over the interest of the species of concern. Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Problems with the ESA (continued) Companies typically have more money and political clout than the agency trying to enforce the regulations, and challenging these companies is very difficult when trying to protect endangered species. Much of the time these companies interests will win out over the regulations set forth by the ESA (Minckley, 2003). Legislative relief and many exemptions have been given to companies and other agencies who would like to use the Colorado River for economic benefit. Provisions for habitat management plans and reasonable and prudent alternatives have successfully pierced the ESA’s armor to allow non-Federal entities to develop and operate projects with a “take” of listed taxa. This is permitted so long as a species’ existence is not jeopardized and the impacts of these projects are offset in some form. Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Conclusion There is no technical solution for solving the problems that State and Federal wildlife agencies are facing to recover Humpback Chub and Razorback Suckers. Human interests have long won out to the detriment of our environment. With concrete penalties and stronger language, the ESA can be revised to fix some of the problems, but it is not likely that fish and game agencies will have the political clout to reform this legislation. The ESA is not a failure because it has provided numerous benefits to endangered fish populations in the Colorado River. The main problem is that private citizens and companies are not very concerned with the recovery of these fish. The support from resource users is not present at this time to ensure that governmental agencies can do more to protect these species. Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness THE END Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Resources •http://www.fws.gov/coloradoriverrecovery/ - Upper Colorado River Endangered Fish Recovery Program •http://cpluhna.nau.edu/Biota/fishes.htm - Land Use History of the Colorado Plateau •http://www.colorado.edu/conflict/full_text_search/AllCRCDocs/9312.htm - The Upper Colorado River Basin Endangered Fish Recovery Initiative •http://www.cowatercongress.org/images/tom%20pitts%20%20upper%20colorado%20river%20endangered%20fish%20recover y%20program.pdf – USFWS Presentation Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness References Bradford, R., S. Gurtin. 2000. Habitat Use by Hatchery-Reared Adult Razorback Suckers Released into the Lower Colorado River, California-Arizona. North American Journal of Fisheries Management, 20 (1): 154-167. Buhl, K., J1997: Relative Sensitivity of Three Endangered Fishes, Colorado Squawfish, Bonylail, and Razborback Sucker, to Selected Metal Pollutans. Ecotox and Env Safety 37: 186-192. Environmental Working Group. 2008a. Mining Surge Near Colorado River Threatens Drinking Water For 25 Million. < http://www.ewg.org/node/2646> 10/29/08. Environmental Working Group. 2008b. Without a Paddle:U.S. Law Powerless to Protect Colorado River From Mining. <http://www.ewg.org/sites/mining_google/ColoradoRiver/index.php?nothanks=1> 10/29/08. Fish and Wildlife Service. 2000. Species information: threatened and endangered animals and plants. <http://endangered.fws.gov/wildlife.html> 10/29/08. Fish and Wildlife Service. 2002. Razorback Sucker (Xyrauchen texanus) Recovery Goals. U.S. Department of the Interior, U.S. Fish and Wildlife Service, Washington, D.C. Fish and Wildife Service. 2006. Why some native fish in the upper Colorado River basin are endangered. http://www.fws.gov/ColoradoRiverrecovery/Crwhynnf.htm 10/29/08 Gelt , J., 1997. Sharing Colorado River Water: History, Public Policy and the Colorado River Compact, Arroyo, Volume 10, No. 1, <ag.arizona.edu/ AZWATER/arroyo/101comm> 10/29/08. Gorman, O. T., and D. M. Stone. 1999. Ecology of spawning humpback chub, Gila cypha, in the Little Colorado River near Grand Canyon, Arizona. Environmental Biology of Fishes 55:115–133. Keading, L. R., and M. A. Zimmerman. 1983. Life history and ecology of the humpback chub in the Little Colorado and Colorado rivers of the Grand Canyon. Transactions of the American Fisheries Society 112:577–594. Marsh, P. C., and M.E. Douglas (1997) Predation by Introduced Fishes on Endangered Humpback Chub and Other Native Species in the Little Colorado River, Arizona. Transactions of the American Fisheries Society: Vol. 126, No. 2 pp. 343–346 Minckley, W. L., P. C. Marsh, J. E. Deacon, T. E. Dowling, P. W. Hedrick, W. J. Matthews, and G. A. Mueller. 2003.A conservation plan for native fishes of the lower Colorado River. BioScience 53:219– 233. Modde, T., K.P. Burnham, and E.J. Wick. 1996. Population status of the razorback sucker in the middle Green River (U.S.A). Conservation Biology 10(1):110-119. Pitlick, J., and M. M. Van Streeter, Geomorphology and endangered fish habitats of the upper Colorado River, 1, Historic changes in streamflow, sediment load, and channel morphology, Water Resour.Res., 34, 287–302, 1998. Valdez, R. A., T. L. Hoffnagle, C. C. McIvor, T. Mckinney, and W. C. Liebfried. 2001. Effects of a test flow on fishes of the Colorado River in Grand Canyon, Arizona. Ecological Applications 11:686–700. Restart the Presentation End the Presentation Resources References Appendix About FCF kim: Introduction History Science Conflicts Relevant Legislation Legislative Effectiveness Glossary Use more complete def. Age ForClass: Fish in the same age range heterogeneity Embryonic: In an early stage of development Headwater: The source of a river Heterogeneity: A state of consisting of dissimilar elements Peak Discharge: The highest rate of discharge of a volume of water passing a given location Predation: The act of preying by a predator who kills and eats the prey Recruitment: The number of new juvenile fish reaching a size/age where they represent a viable target for the commercial, subsistence or sport fishery for a given species Sediment Load: The solid material that is transported by a stream Tributary: A stream or river that flows into a larger one Turbidity: Having sediment or foreign particles stirred up or suspended; muddy Viable: Capable of life or normal growth and development Watershed: The region draining into a river, river system, or other body of water Restart the Presentation End the Presentation Resources References Appendix About FCF Introduction History Science Conflicts Relevant Legislation APPENDIX 1) Silt gets trapped behind dam Legislative Effectiveness 2) Flow is restricted by dam As a result river carries less silt, has restricted flow, and is much cooler 3) Intake in deeper cooler region of lake Back To Presentation Restart the Presentation End the Presentation Resources References Appendix About FCF