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future directions for flood control system improvements. Fountain Creek and Tributaries Flows from Fountain Creek and its tributaries run directly into the Arkansas River below Pueblo. Increases in base flow from water transported across the Continental Divide to Colorado Springs that are discharged into Fountain Creek following use and treatment by the city has occurred since 1952 with the construction of the Hoosier Tunnel Project. This was followed by the construction of the Homestake Water Development Program in conjunction with the City of Aurora in 1965. Finally, the Bureau of Reclamation completed construction of the Fryingpan- Arkansas Project in June 1981. The water rights to the share of water received by Colorado Springs through these projects are fully controlled by the city. These rights continue for any discharge of this, so-called, "trans- mountain water" into Fountain Creek. The city is credited for the discharge of trans-mountain water into Fountain Creek (and therefore the Arkansas River) through storage of Arkansas River water at Pueblo Dam. This water is stored under a so-called "if and when" arrangement. Under this arrangement, if storage volume is needed for flood control or when downstream irrigation districts place a demand on the storage volume, the water credited to Colorado Springs is released. At that point, Colorado Springs rights to those waters are lost. The city also loses rights to waters lost through evaporation, ground percolation and bank losses during transit down Fountain Creek. Colorado Springs is able to make use of water stored at Pueblo Dam by pumping water back up through the Otero pipeline. The increased base flow down the Fountain Creek and Arkansas River by discharges of trans- mountain water does artifIcially affect the channel capacity to some degree. More importantly it may have created a signifIcant imbalance within the creek and river system that forced changes in the system in an attempt to achieve a new equilibrium. This adjustment process may be taking the form of more meandering, increased bank erosion and charrnel bed degradation in some reaches and increased aggradation ofthe charrnel bed in other reaches. This on-going natural process has negatively impacted upon properties along Fountain Creek in incorporated and unincorporated areas like Colorado Springs, Manitou Springs, Security, Fountain, Pinon, Pueblo and others. As indicated earlier in this report (see Table 3-3), this process may also be contributing to the accelerated aggradation within the Arkansas River since 1965. Development on Fountain Creek in the City of Manitou Springs has severely encroached upon the floodplain. In the downtown area, Fountain Creek is reduced to a narrow channel with a conveyance capacity of around 1,000 c.f.s. This equates to approximately the 10-year frequency flood. A reconnaissance report by the Corps of Engineers in May 1995 (revised August 1996) indicated that flood-warning systems providing 15 minutes to 3 hours advance notice of flooding on Fountain Creek do not allow suffIcient time for emergency evacuation procedures. The economy of Manitou Springs is highly dependent upon tourism. The tourist season coincides with the summer flood season and creating a severe flood management problem. The speed at which flows could overflow the narrow charrnel and create fast moving floodwaters several feet Post Flood Assessment Report 28 Chapter 3 - Flood of April 29, 1999 Draft Revised 09/09/99