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<br />L'R <br /> <br />including the endangered razorback sucker. The Upper Colorado River Basin Recovery Implementation <br />Program has targeted acquisition of floodplain wetlands within the I DO-year floodplain, and reconnecting <br />floodplain wetlands to main channel flows to assist with recovery activities. These activities are based on <br />the following assumptions; <br /> <br />I. Riparian wetlands constitute critical rearing habitat for razorback sucker; <br /> <br />2. The current low populations of these fish are related to a decrease in the availability ofthese <br />habitats; and, <br /> <br />3. Flooded bottom lands can be manipulated and managed (i.e., via levee removal) in such a way <br />as to increase rearing habitat and enhance survivorship of young razorback suckers. <br /> <br />General Recovery Program Support <br /> <br />II. <br />ILA. <br />1I.A.1. <br /> <br />Restore Habitat <br />Restore flooded bottomland habitats <br />Conduct inventory of flooded bottomland habitat for potential restoration <br /> <br />Green River Action Plan <br /> <br />II. <br />II.A. <br />1I.A.1. <br /> <br />Restore Habitat <br />Restore and manage flooded bottomland habitat <br />Conduct site restoration <br /> <br />III. Study BackgroundlRationale and Hypotheses: <br /> <br />The overall strategy for the Levee Removal Program is to remove levees from selected floodplain wetlands <br />on a sequential temporal and spatial scale so the response of fish populations can be carefully evaluated <br />(see the Levee Removal Strategic Plan, Lenll;ch et al. (1996) for It'lee removal details). The methods for <br />levee removal activities, including sampling gear and sampling protocols, were revisited after the 1996 and <br />1997 activities and are presented in this revised SOW. The methods identified below will be followed after <br />levees have been breached/removed, starting in late summer 1996. The overall workplan (\997-1999) <br />outlines a temporal and spatial strategy to determine the fish population response and dynamics of <br />'restored' and natural floodplain areas. It contains a monitoring program designed to determine the fish <br />food (zooplankton, macroinvertebrate, etc.) and fish population response associated with these wetlands. <br /> <br />Previous research has documented the importance of low velocity habitats (backwaters) within the main <br />channel as habitat for native fish. The formation and maintenance of these nursery habitall; are currently <br />under investigation (Schmidt) as is the importance of these areas to Colorado squawfish population <br />dynamics (UDWR) and razorback suckers (Vernal, CRFP). Floodplain wetlands represent an additional <br />level of habitat and biological complexity and are potentially very important for endangered fish recovery. <br />Their functional re-connection in the Upper Colorado River Basin may be especially important given a <br />general reduction in channel and floodplain complexity over the last 100 years. This reduction can <br />generally be associated with dam construction and flood management activities. <br /> <br />Floodplain wetlands are generally areas of high primary productivity. They possess elevated temperatures, <br />nutrients and light intensities. Decay of plant material (emergent and flooded terrestrial vegetation) <br />supports a large decompositional pathway within the overall food web. The production of food organisms <br />for fish is correspondingly high because of a large food base (phytoplankton, etc.), 8 structurally complex <br />environment (structure provided by emergent plants, flooded vegetation and algal mats), and wanner water <br /> <br />2 <br />