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Primary and Secondary Trophic Levels Measurements to evaluate primary and secondary trophic levels were collected from a representative riffle and run within three randomly selected reaches within each stratum. Samples were collected from five locations parallel to the shore at approximately 1 to 1.5 ft water depth within these two habitats. These samples were collected from locations that were similar in depth, velocity and substrate within each sample reach and habitat to aid in a longitudinal comparison. Physical Parameters -Physical parameters (Table 1) collected within each sample reach were those assumed to have the greatest influence on primary and secondary trophic levels based upon literature data. Most parameters were collected at each sample location parallel to the shoreline. Water quality parameters were also collected for each reach and stratum. Water column depth, bottom velocity and mean column velocity (0.6 depth) were collected at each sample location. Depth was measured with a stadia rod and velocities with a Marsh-McBirney current meter. The percent of cover of the two dominant substrate size fractions was estimated at sample locations. Wolman pebble counts (Wolman 1954) were also conducted within the vicinity of the five samples parallel to the shoreline to quantify the size distribution of substrates in these regions. The percent embeddedness of large substrates at each sampling point was estimated from the portion of the substrate exposed above interstitial sediments. Depth to embeddedness was measured as the distance from the top of large substrates to the upper layer of interstitial sediments. Interstitial substrates were collected at each sample location with a core tube, with samples dried in the laboratory and separated into size fractions. The percent organic composition of the smallest sediment size fraction (< 2mm) was measured and used as an estimate of fine particulate organic matter (FPOM). Water samples were collected from each sample reach and each location in the synoptic survey. These samples were analyzed in the laboratory for ammonia, nitrate, nitrite, total nitrogen, orthophosphorus, total phosphorus, and turbidity. Field measurements of light extinction were conducted at each sample reach with light measurements taken at multiple depths using a 4-pi collector. Drifting organic matter was collected in drift nets set within each reach. Nets were set for one hour immediately after sunset. The spatial distribution of riverine habitat within each survey reach was mapped at the conclusion of the study (fall 1996). This mapping was used to quantify the extent of major surficial habitats within each reach. Habitats were drawn on airborne videography, orthocorrected and transferred to a GIS basemap for interpretation. Categories of mapped habitats can be seen in Table 2. 6