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Method 5 - The radial subsurface collector consists of a series of hor:Lzontal screen pipes which extend out radially from a vertical reinforced concrete caisson which has been sunk to the base of the aquifer adjacent to the surface water source (t.he Uncompahgre River in this case). Based on the li4:erature provided, this appears to be a very thorough method of filtration. However, it would be more expensive than 4:he other alternatives. Seepaqe Lininq - 'I'he seepage analysis in section 8 showed that if 1:he drain on the east side of the pond were filled with impurvious material, the total maximum seepage rate would not uxceed 1 cfs, even if the portions of the pond to be exca"ated are not lined. However, caution must be exercised if any disturbances are made within the perimeter of thu seepage blanket limits. Such a disturbance could alter the seepage flownet, and the seepage analysis would need to bu repeated to determine the effect. of the disturbance. Pumpinq - j,s previously discussed, pumping will probably not be required to provide adequate hydraulic head (with possibly 1:he exception of low flow periods). Cost considerations ::or a pumping alternative (if furt.her considered by the city) should include 1:he significant operating costs required for electricity and maintenance costs, in addi.t:.on to purchase and installa.tion costs. other Cos.t Considerations - ot.her costs that will be associated with the design and construction of the diversion facility will include potential environmental impact studies, engineuring and design costs, project supervision and administrat:.on costs, and contingency costs. For the above items on H project of this magnitude, it would be reasonable to aBsume these costs to total an additional 40 to 60 percent 0:': the basic construction first costs. Environmental s1:udies costs could vary grea.tly. Engineering and design would be approximately 10 to 15 percent. proj ect supervision and administration generally vary from 5 to 10 percent. Contingency costs are prudent to account for unexpected projllct conditions - values in the 15 to 25 percent range al:e commonly used. Many desicrn measures are available to divert, convey, screen/filter, and retain diverted flows from the Uncompahgre Rivur to the adjacent fish pond. This chapter has summarized 1:hese al ternati ve measures. 'rhe next step is for the city to have a professional engineer design the diversion facil:,.ty based on the city's preferences. It appears that a design diversion capacity of 5 cfs will be adequatE.! to account for maximum evaporation, seepage, waterfowl area, and irrigation needs. This study has not dealt w:.th water quality considerations and associated flow requirements. Prior to final design of the 17