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<br />::'J. 1 . <br /> <br />002738 <br />Opportunities for Ecological Improvement Along the Lower Colorado River <br />Mark Briggs and Steve Cornelius <br />7/24/97 <br /> <br />need to focus on protecting additional native wetland habitats. Such efforts could help <br />minimize direct impacts from a variety of human activities. For example, unrestricted <br />vehicular traffic can significantly reduce the use of marshland and open water areas by <br />waterfowl (Anderson and Ohmart 1988). Oosing off or reducing traffic to critical <br />marshland areas is one way to improve the utility of available habitat to wild species. <br /> <br />8. Modify Reservoir Operations and Water Use Practices <br />Altering dam releases to enhance or maintain the Colorado River's wetland habitat <br />needs to be a future priority. The successful completion of the 1996 test flow or Hflood" <br />from Glen Canyon Dam to restore river beaches may set the stage for further <br />manipulations of dam releases for environmental purposes. H such artificially- <br />produced floods can remove sand and silt out of reservoir storage to downstream sites, <br />a variety of objectives could be accomplished. Depositional bars can be created to <br />enhance natural propagation of native riparian plant species and backwater breeding <br />areas for many native fish can also be created immediately downstream of newly- <br />formed depositional bars. <br /> <br />Performing such releases for environmental purposes may be more likely than before <br />as flood water management along the lower Colorado River in the last decade is <br />changing because Lake Powell behind Glenn Canyon Dam has filled to near capacity. <br />This means that flood flows will probably pass through Glen Canyon Dam much more <br />frequently, significantly increasing the amount of water brought into the lower reaches <br />of the river and the delta (payne et al. 1992; Glenn et al. 1996). H this scenario is <br />accurate, a variety of restoration/conservation opportunities may exist that were not <br />possible before. <br /> <br />9. Resolve HOther" Water-Related Issues <br />Along the lower Colorado River and in the delta there seem to be numerous areas that <br />are ecologically damaged due, at least in part, to water-related issues that are not <br />directly associated with reservoir management and water allocation. These H other" <br />water-related issues include addressing groundwater over-pumping, water pollution, <br />and improving water conservation measures (Morrison et al. 1996). In comparison to <br />altering dam releases or allocating water for environmental purposes, tackling some of <br />these issues may be an effective way of realizing short-term ecological improvements. <br />Implementing water conservation measures to reduce groundwater pumping in areas <br />such as Mexicali, Blythe, and Yuma could reduce drawdown of nearby wetlands. <br /> <br />10. Use Wastewaters More Effectivelv <br />The river has approached the point of full utilization where essentially every drop of <br />water that passes through is spoken for. Therefore, obtaining significant amounts of <br />water specifically for wetland enhancement will become increasingly difficult On the <br />other hand, the amount of wastewater - agricultural drainage and municipal effluent _ <br />is growing significantly. Although this water cannot be used for human use, it is well- <br />suited for maintaining wetland vegetation (Glenn et al. 1997). Already a significant <br /> <br />Page 26 <br />