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I I I I I I I I I I I I I I I I I I I Water StoraQe and Water Qualitv As described previously, two storage reservoirs are conceptualized for the pressurized irrigation system: Highland NO.3 Reservoir and a new reservoir in Phase II. Highland No. 3 Reservoir holds two storage decrees which belong to the Highland Ditch Company. The new reservoir location is near several existing private storage reservoirs. It may be possible for the Highland Ditch Company to negotiate with the owners of the nearby reservoirs for use of those facilities which would then eliminate or significantly reduce the cost of constructing a new storage facility, Some improvements to the existing facilities may still be required, including expansion and lining. Water can be delivered to both of these locations through existing Highland Ditch structures. The recommended size for the new storage facility in Phase II is approximately three times the peak season daily irrigation water requirement being pumped from that reservoir (assumed to be for Phase II, III, and IV). This size will allow for flexibility in the delivery schedule to each reservoir and "insurance" that the irrigation system can continue to operate normally in an event where water cannot be delivered for a few days, This reservoir would have approximately 220 acre-ft of "usable" storage. The preferred storage facilities for this project are excavated ponds with either a PVC liner system or a bentonite clay liner. The PVC liner system would include a 30 mil PVC liner and 8-ounce geotextile fabric, and 12 inches of soil backfill above the lining system. A 12-inch depth of soil over the geotextile is required to protect the liner system and create a natural appearance. Typically, the PVC liner is more costly, and therefore it has been included in the cost estimates to be conservative. The new reservoir should be excavated to contain a water depth of 25 feet. The side slopes of the pond should not be steeper than 4H:1V for safety issues and liability concerns. The surface area of the proposed reservoir will be approximately 12.5 acres to store about 220 acre-ft of usable irrigation water based on the above design criteria. A common issue when using raw water for irrigation is the potential for poor water quality, specifically algae blooms and odor problems. In order to minimize the risk of this occurring, lake bed aeration systems are recommended. Lake bed aeration systems do not mechanically move the water or aerate it by spraying it into the air. Rather, lake bed systems aerate ponds by bubbling air or a combination of air and ozone through the water. This method is significantly more efficient, is not noticeable unless the water surface is totally calm, and is less expensive to operate. The air bubbles out of laser cut slits, spaced 3-inches apart, in polyethylene pipe that is weighted in order to sink to the bottom of the pond. Typically the tubing sections are 250 feet in length with several sections being used in large ponds. Exact length and compressor requirements are based on pond volume and water depth in the pond. Alternatively, localized aeration modules can also be used in lake bed aeration systems where several modules take the place of the weighted tubing. As water is pumped out of the pond and replaced on a consistent basis, the turnover of water is relatively high and the opportunity for water stagnation or algae blooms is reduced. The mechanical components required for the aeration system will be located in the pump system building adjacent to the reservoir. These components include an air compressor, air filters, flow meters, ozone generators, and a system timer. Maintenance of the Aqua Engineering, Inc. November 8, 2004 Canal Modernization Feasibility Study - 20-