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<br />Table 4. Predicted change of resources and ecosystem processes manipulated by different engineering techniques from <br />conditions that existed in 1990, <br /> Engineering technique <br /> Maximize revenue <br /> from power <br /> production Use elOning structures Modify structures <br /> Sediment <br />Management resources and Maximum power- Seasonally adjusted augmeDtatioD Thermal <br />ecosystem processes plant capacity steady flows CODtrolled floods and floods modification <br />Water <br />Reservoir storage in Lakes Powell No change More fluctuations Scheduled minor Scheduled minor No effect <br />and Mead decrease decrease <br />Water quality (dissolved) in No change No change Increased flux Increased desorbed Decreased nutrient <br />Colorado River of salts constituents load <br />Monthly median streamflows No chan~e More variable More variable More variable No change <br />Flood freq uency Rare spil s Rare spills More frequent More frequent No effect <br />Sediment <br />Width of sandbars Decrease Increase No change Increase No effect <br /> or decrease <br />Hei~ht of sandbars Increase Decrease Increase Increase No effect <br />Pro ability of net long-term gain No change Increase No change Increase No effect <br />of riverbed sand <br />Frequency of flood erosion of high No change Decrease Increase Possible decrease No effect <br />terraces adjacent to river <br />River's capacity to move bouldets No change Decrease Increase Increase No effect <br />in rapids <br />Benthos bmacrophytes and No change Increase Decrease Decrease Increase <br />invene rates) <br />Trophic suucture <br />Benthic production Decrease Increase, compo- Decrease Decrease Increase <br /> sition change <br />Woody debris decomposition Increased wetting Decreased wening Increased wetting Increased werting Increased <br /> and drying and drying and drying and drying decomposition <br />Organic drift No change Decrease Initi:ill increase, Decrease lncrease <br /> possible later <br /> Clecrease <br />Fishes <br />Native fish Decrease Possible increase Possible increase Possible increase Increase <br />Mainstem reproduction None None None None Increase <br />Tributary reproduction Restricted Restricted No effect No effect No effect <br />Mainstem recruitment and growth No change Possible increase Possible increase Increase Increase <br />Non-native, non-sport fish Stable or decrease Possible increase Stable or decrease Stable or decrease Increase <br />Interactions between native and No change Possible increase Decrease Possible decrease Increase <br />non~native fish <br />Tailwater trout fishery No effect No effect No effect Depends on Increase <br /> input point <br />Tailwater reproduction No change Increase Possible decrease Decrease if input Increase <br />and recruitment at dam <br />Downstream reproduction No change Increase Unknown Decrease Increase <br />and recruitment <br />Ritharian Yeg~tation Decrease Decrease Decrease Decrease No effect <br />pper C1'panan zone <br />Lower nparian zone (marsh and No change Increase Decrease Decrease Possible no effect <br />vegetated sandbars) <br />Terrestrial Fauna <br />Population No change Possible increase Decrease Decrease Increase <br />General recruitment Increase Stable Decrease Decrease No effect <br />Kanab ambersnail No change Increase Decrease Decrease No effect <br />Bald eagle No change Possible decrease Decrease or Decrease Increase <br /> no effect <br />Southwestern willow flycatcher No change No change No change No change No effect <br />Belted kin~fisher No change No change No change No change No effect <br />Archaeological and historical features No change No change Possible increased Possible increased No effect <br /> protection protection <br />Recreation <br />Tailwater angling No change No change No change Depends on Increase <br /> input point <br />Tailwater day rafting Decreased quality Improved quality Decreased quality Decreased quality Improved quality <br />White-water boating Increase and <br />Trip quality No change Increase Possible increase Increase <br /> decrease <br />Usable camping beach area Decrease Decrease Increase lncrease No effect <br />Pathogenic bacteria No change Possible increase Decrease Increase Increase <br />Economics No change Increase No change Possible increase Possible increase <br />Power Production <br />~erations Unconstrained Constrained Minor constraints Minor constraints No effect <br />olesale and retail rates No change Increase Increase Increase Increase <br />Non-use values. 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