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272 contain water of uniform quality and low in mineral content (60 p/m total dis- solved solids) because of the granitic bedrock, therefore eliminating these conditions as a bias when comparing aquatic habitats. AQUATIC ENVIRONMENT EVALUATIONS The streamside and aquatic environment documentations used the general methods outlined by Herrington and Dunham (1967) with some modifications. The modifications were made to increase sample sizes in small drainages and to quantify additional physical conditions as described later. The aquatic methods satisfactorily quantified most of the variables, as water depths rarely exceeded 48 inches and water velocities were never exces- sive for in-stream work. The clear water with low flows (July-November) offered excellent conditions for observation and measurement. The studies were conducted from 1970 through 1972. Stations The environmental condition of the 38 major tributaries within the study area, totaling 135 stream miles, was documented by using an average of one transect for every 93 yards of stream. Stations were located randomly along all study streams from mouth to headwaters (where the stream became ephemeral). Each stream contained a minimum of six stations regardless of stream length. Each stream area (station) to be physically analyzed was selected randomly, marked on an aerial photograph (1-15,000), and then located and marked on the ground. The first transect of the five grouped transects (at 50-foot inter- vals) making up each station was located 100 feet upstream from the photographic location to avoid any bias resulting from the tendency of field personnel to establish the actual point where access may be easiest. Transects A transect (channel cross section) is defined as an imaginary line run- ning perpendicular to the centerline of the stream. The following measurements and conditional factors were recorded: 1. Stream, pool, and riffle widths. 2. Four stream depths at equal intervals across the stream. 3. Ratings, locations, and features of pools. 4. Stream channel surface material classifications. 5.. Cover, conditions, and types of streambanks. 6. Channel elevations and gradients.