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I I I I I I I I I I I I I I I I I I I It is felt that 1954 was likely only a drought stage 1 event because of the approximately 8,900 AF that was delivered to Lake Canal. The 1977 and 1987 droughts were likely drought stage 2 events. Note that three of the four droughts are quite similar in the magnitude of the drought and the theorized response, The perception is that these three droughts would have resulted in a triggered response but note that the level of response would not have likely been a significant problem for urban irrigators under the Lake Canal system. Yes, there was need to respond to the conditions but is the drought stage 2 response really a difficult problem to deal with? The 2002 drought, the critical drought for the Poudre Basin for the 119 years of record, is thought to be a drought stage 4 event. The predicted trigger and the response, a drought stage 4, include mandatory restrictions. Specifically, drought stage 4 would likely require "Residential irrigation limited to 2 days per week by house number. Parks irrigation limited to high use areas and sports fields. Golf course fairways are deficit irrigated." This drought analysis, specific to the Lake Canal system and specific to the future build out of Lake Canal urban projects would suggest that a secondary supply system under Lake Canal could easily survive the 50 to 100-year drought event and the 300-year drought event, as in 2002, is also a survivable situation. This analysis can be briefly summarized as follows: · Analyzing normal stream flow years and Lake Canal diversions shows that there is adequate water for a future build out of urban landscapes. · Analyzing past drought events in the Poudre Basin and comparing water availability with projected water requirements shows that there would likely be enough water for priority landscapes (public use areas such as sports fields, parks, and golf courses) in the future under even severe drought conditions. · A concept of triggers and drought responses has been developed for consideration. · Only the worst year of drought in the written record (2002) would have likely necessitated a drought stage 4 response. Service Area and Pumtill1g Requirements Service Area and Irriaated Area As conceptualized, the pressurized infrastructure pipe system will serve an area of approximately 7,700 acres. This area was determined from the current Lake Canal Company service area as shown in aerial photographs and GIS maps. Several assumptions were made to determine the water use requirements and overall sizing of the pump stations and pipelines. The first assumption is the actual future irrigated area to be served by the system. The irrigated area is the fraction of total Aqua Engineering, Inc. June 7, 2004 Canal Modernization Feasibility Study - 9-