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Show Alternative C: Investigate and monitor water sources for rivers and streams ( preferred alternative) • - A program of research and monitoring would be established to study the hydrodynamics of recharge and flow in intermittent streams. This program would be consistent with, and very likely part of, baseline research on springs and seeps. The objective of this program would be to establish specific water sources and minimum flows required to maintain the riparian ecosystems. In a similar vein, seasonal discharge patterns in the lower Escalante River would be monitored to supplement data from existing gauging stations on the Paria, Dirty Devil, San Juan, and upper Escalante Rivers. An objective of this monitoring would be to establish instream flow rates consistent with maintaining natural riparian vegetation. The effect of tamarisk along streams would be investigated to assess water depletion rates caused by the plant and subsequently to develop a monitoring plan. III. H. 3. Recommended course of action. Under Alternatives B and C, a policy for protecting riparian waters would be established requiring the maintenance of minimum flows for riparian ecosystems when evaluating competing uses of watersheds. Included in the policy would be the specific goal of maintaining water quality in riparian zones and curtailing its degradation by livestock or other users of riparian waters. Stream flows and the discharge of springs and seeps would be monitored periodically. Recharge zones would be defined, and the effect of tamarisk on water depletion at springs and seeps investigated. 111.1. Water Resources as Habitat for Fish III. 1.1. Statement of the problem. III. 1.1. a. Lake Powell-- Glen Canyon Dam changed the aquatic ecosystem above and below the dam so dramatically that many native fish species could not adapt. A few of the native fish species that once inhabited the Colorado River are believed to be still present in the lake, but they are probably associated with the influent tributaries. Most notable among these species are the Colorado River squawfish and the razorback sucker, which appear to be present in the upper lake near rivers. These are long- lived fish and it is not known whether they are reproducing within the recreation area. Lake Powell is not suitable spawning habitat for these fish, but it is possible that the lower reaches of influent rivers may still contain breeding habitat. Lake Powell now supports an outstanding sport fishery based on a variety of fish species adapted to the lake environment. The Lake Powell fishery is unique among Utah's waters. It is not only the state's largest and most important sport fishery, it is one of the few warm- water 42 |