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I I I I I I I I I I I I I I I I I I I service area to be irrigated with landscape irrigation systems. These areas include parks, open spaces, rights-of-way, golf courses, streetscapes, commercial lots, schools and public spaces, multi-family housing areas, and individual residential lots. For the water requirement elements of the study, it is assumed that the actual irrigated area is 30% of the total service area, or about 2,310 acres. Pumpina Reauirements The peak season daily water use was calculated for 2,310 acres. It is assumed that irrigation will occur over an average 12-hour watering window, seven days per week. Water requirements were calculated based on lcIistorical averages, bluegrass turf water requirements, and assumptions made during this modernization feasibility study. Peak season daily application rate in the Windsor I Fort Collins area is estimated to be 0.29 inches for bluegrass turf. The crop coefficient used for turf is 80%. The crop coefficient is a parameter used by various irrigation scheduling methods to scale potential evaporation and transpiration (evapotranspiration) to the actual levels for the particular crop, which was assumed to be entirely bluegrass turf for simplifying this analysis. Bluegrass consumes more water than other common grass varieties and the seasonal water requirement for bluegrass also compares favorably with most shrub bed plantings. So, a bluegrass assumption for purposes of this analysis is somewhat conservative. The seasonal irrigation requirement for bluegrass turf is approximately 30 inches. However, it can range from 28 inches to 36 inches depending on the desired appearance and use of the area. For instance, Fort Collins Parks and Recreation Department applies 32 inches annually for their heavily used parks. Some golf courses in the vicinity may use 36 inches, or more, to maintain the desired aesthetic appearance in areas of high traffic. In order to develop the conceptual plan and cost estimates, the above assumptions were made to represent the "average" requirements within the service area. Although some parks may need to be irrigated in a shorter watering window, say 8-hours, there are also areas such as streetscapes that can be irrigated in a longer watering window, say 16 hours. Drip irrigation, because of low evaporative losses and high application efficiency, is generally acceptable outside of an otherwise assumed or imposed water window. Therefore, applying a watering window of 12 hours to the entire area allows for anticipated variations from site to site. Additionally, some turf areas will require more than 30 inches of water and some areas will require less, so an average of 30 inches per year was applied to the overall irrigated area. Table 6 summarizes the assumptions made to determine water requirements for the irrigated areas served by this system. Aqua Engineering, Inc. June 7, 2004 Canal Modernization Feasibility Study - 10 -