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the summer, stream temperatures can be very warm. Dissolved salt concentrations can exceed 3,000 parts per million, and oxygen content is usually moderate. Riffle areas during low flow months are normally knee-deep while pools are several feet deep. Undercut banks are common, while streamside vegetation is usually composed of grass or brush. When the streams and rivers on the eastern side of the Continental Divide flow out of the mountains and onto the plains these waters pass through a transition zone. In periods other than spring runoff, water velocities slow, water temperatures are moderate and the water is clear. Deep pools, undercut banks, streamside vegeta- tion of grass and shrubs, and tree cano- pies are all common features of these waters. These stream reaches are a buf- fer between the upstream coldwater trout stretches and the downstream warmwater segments. The number of fish species found in the segment may be the highest of any stretch of the river as populations from the coldwater and warmwater por- tions are both present. The two mainstem portions of the Arkansas and South Platte rivers that flow from the mountains out across the eastern plains present somewhat similar habitats. Once these rivers have left the transition zone from cold to warmwater the river changes in character. Instead of one main channel, the rivers may gradually sub- divide into a braided series of parallel channels moving down a wide, sandy bot- tomed riverbed. As flows change, the various channel braids move back and forth across the stream merging and separating into different flow patterns, There are often islands within the stream bed while the riparian vegetation zone can be from two-to-several hundred yards wide. A tree canopy covers at least part of the river in many areas. Water depths may be only a few inches during low flow conditions and summer water tempera- tures are quite warm. Total dissolved salt concentrations increase to a level of more than 4,000 parts per million in the lower Arkansas. Species found in these river segments must be able to tolerate drought, flooding, high turbidity and changing habitat conditions. Most tributaries of the Arkansas and South Platte in the eastern plains of Col- orado are intermittent in nature. Fed by runoff or surfacing groundwater, some of these plains streams maintain permanent flows in the headwater regions while most have year-round water only in potholes. Windblown weeds or growths of aquatic vegetation choke many of these potholes. Water temperatures can be very high unless trees canopy the water. Stream substrate varies from sedimentary bedrock to mud and silt. Throughout the state, a surfacing spring or surfacing groundwater may create a rather unique stream in any of the habitat regions previously described. Flows surface year-round assuring perma- nent flow, and stream banks tend to be rather stable since an established riparian zone reduces erosion. Water temperatures usually remain fairly cool in these stream reaches even in summer months and aquatic vegetation often flourishes. This situation is common in the Republican River Basin on the eastern edge of Col- orado. These permanently flowing streams are a refuge for species requiring moderate environmental conditions which may not exist in a drainage basin drastically impacted by man's activities. Colorado's Little Fish Bijou Creek is an example of a sandy-bottomed Plains stream.