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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />t <br /> <br />Principal Flood Problems and History <br /> <br />Fort Collins is vulnerable to flooding from several different sources. Flood sources include; 1) <br />the rivers and streams in Fort Collins which include the Cache La Poudre River, Spring Creek, <br />Dry Creek, Fossil Creek, Cooper Slough, and Boxelder Creek; 2) potential dam failure, and; 3) <br />urban flash flooding from intense rainfall on smaller drainage basins. The main cause of floods <br />in the Fort Collins area is intense rainfall, which normally occurs in the periOd of May through <br />September. <br /> <br />Of all the floodplains within the City, Dry Creek is the most developed with regard to the <br />number structures and people at risk. The majority of development within the Dry Creek <br />floodplain is "pre-Firm", meaning that it was developed prior to the City and County entering the <br />National Flood Insurance Program (NFIP) in 1979, and therefore, the majority of structures do <br />not meet the minimum design and construction criteria established by the Federal Insurance <br />Administration (PIA) and FEMA which are intended to reduce flood damages and losses. In <br />addition, most of the pre-Firm commercial and residential properties do not carry flood insurance <br />unless they have been "substantially improved". <br /> <br />Dry Creek has not had serious flooding below the Larimer and Weld Canal (Eaton ditch) since <br />the early 1950's. This absence of even minor flooding is generally attributed to the network of <br />irrigation canals that have some capacity for intercepting small to moderate Dry Creek flows up <br />to about the 5-year event. Flood history prior to this time period is unclear. Before substantial <br />development occurred in the area, flows could often be ignored where little damage was <br />incurred. <br /> <br />The flood of 1904 is documented in a newspaper account which stated that "the Water Supply <br />and Storage company got a lot of water from Dry Creek, storing in the Rocky Ridge reservoir at <br />the rate of nearly 500 feet per second". One death from the 1904 flood is documented, John <br />Parkinson, a 7-year old boy, drowned. The family lived near the Eaton Ditch, which overflowed <br />above their house after they had gone. to bed. <br /> <br />Flooding also occurred in 1924 with flows several feet deep in the vicinity of College Avenue <br />and Hickory Street It is unclear as to whether this was actually due to overflows from the Poudre <br />River. <br /> <br />Dry Creek has several lakes and storage reservoirs which reduce the contributing drainage area <br />by approximately 13 percent, although they are not really flood control structures. Douglas <br />Lake, located outside Fort Collins corporate limits is also an irrigation reservoir that provides <br />about 15%-20% flood flow attenuation for the 100-year event. <br /> <br />2 <br /> <br />