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The traditional screening in the service spillway, which also acts as the flood spillway, would present a problem for passing flood flows. There is no precedent for screens on structures of this type (Miller and Laiho 1997). The alternative is to place a floating screen out in front of the spillway such as a kevlar net. This could be feasible but there are likely problems that will occur with maintenance and operation especially during periods of flows higher than the average runoff. Based on observations made during this study, debris may become a problem and become entangled in a net and compromise the integrity of the net itself. Large debris, such as large trees, was observed moving through the reservoir and over the spillway during the study period. The spillway nets also have problems with fouling from algae growth and other organic debris coming through the reservoir. In addition to fish escapement, large woody debris, was observed exiting the reservoir at the spillway. Some of this debris was over 20 feet long and 1 foot in diameter. Debris this size would pose a danger to any surface screen (fixed or net) installed at the spillway and require additional maintenance on the screens. The debris load should be considered when determining screen type and location for the reservoir. The selected alternative for this application to minimize escapement from the reservoir without compromising structural integrity of the dam is a screen on the low level outlet works of the enlarged reservoir and operation of the outlet works to maximum capacity. + Enlargement of the reservoir will place the outlet capacity at nearly 600 cfs which would allow screening of approximately 80% of the, flow at the average peak. Average peak flow is approximately 800 cfs (Figure 11) based on USGS data for gage 09246400. The proposed outlet works would release up to nearly 600 cfs. Data from this study shows that there is minimal escapement at flows less than 175 cfs which would be the flow over the spillway during average peak flow. This condition would exist based on the data shown for less than three weeks for an average year. Approximately 200 cfs would be released from the spillway in average years for approximately three weeks. Currently flows greater than 200 cfs pass the spillway for nearly two months. The peak discharge occurs in mid-May (Figure 11). Based on the timing of the peak flow, smallmouth bass spawning would likely not have taken place in mid-May. Graham and Orth (1986) report peak spawning for smallmouth to occur after runoff and when water temperatures are between 15 °C to 20°C. FINAL REPORT - Elkhead Reservoir Escapement, Project No.: 118 Page 18 Miller Ecological Consultants, Inc. May 20, 2005