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FLOOD CONTROL ditch laterals and lawn watering adjacent to the creek has contributed to bank fail- ure through increased pore water pres- sures. l J.. .~ .4,.. ~" , l . 1be Planning Process The first floodplain management planning on Fossil Creek was the "Fossil Creek Master Drainageway Plan" in 1982, Prior to the 1982 study, residential and conunercial development had not been a major issue in this part of Fort Collins, therefore flooding and erosion went for the most part unnoticed. The 1982 study included a detailed flood- plain study and a general sedimentation and erosion analysis, The erosion analy- sis included a qualitative stability study and stream bank inventory and identi- fied urbanization and associated streambed degradation as an underlying cause for channel instability, One of the initial impetuses to implementing stability studies along Fossil Creek came from observing years of development along a tributary to Fossil Creek, Mail Creek. Development 'i ;<. " . ,. ~ along Mail Creek occurred prior to the recognition of stability problems, Years of development along the banks of Mail Creek lead to increased loss of property from accelerated bank erosion, increased safety hazards from high banks associated with an entrenched channel, aesthetically degraded reaches, piecemeal bank protection which increased erosion in other areas, degrad- ed habitat, poor water quality due to increased sediment loads, and an upset public who lived along the banks of the creek. Currently, Fort Collins is growing at a rate of nearly 4% annually with the Fossil Creek area experiencing some the greatest growth pressures, There are multiple proposals for large subdivision developments in the Fossil Creek basin, many of which are proposed along the banks of Fossil Creek. Recognizing the increased growth pressures and channel stability problems, Fort Collins Stormwater Utility decided to incorpo- rate channel stability studies into Master Planning. J j i:: KEf .R.1RATDt The geomorphic complexity of allu- vial streams, such as Fossil Creek, cre- ates difficulties for implementing federal floodplain regulations that are based pri- marily on flooding, In fact, channel changes such as meander migration and bank erosion, has generally constituted a greater hazard than overbank flow along Fossil Creek, except in backwater areas associated with culverts and road cross- ings. Applied Geomorphology and Floodplain Management The methodology used for the channel stability analysis consisted of hydrologic, hydraulic, sediment trans- port, and geomorphic analyses, Field investigations are a critical part of any geomorphic study, The field study con- sisted of surveying cross-sections, identi- fying areas of bed level changes, locat- ing and characterizing areas of signifi- cant bank erosion, collecting bed and bank material samples, estimating chan- nel and overbank roughness, identifying natural and manmade controls, and pro- At last storm water inlet protection that works without all the problems and drawbacks of traditional inlet protection. ,~ ,{ l . . . . . . . Protects side slope inlets (grade) as well as low point inlets (sump) without bypass or flooding, which is something no other inlet protection can do. Increased filtration area, making it far more effective at controlling sediment and debris than traditional methods of protection. . ~ ~~ Can be installed in just minutes and is located inside the storm drain inlet so it is protected from damage due to traffic andlor construction activities. " . ,t~ Provides effective protection at the last location that sediment and debris can enter into the storm sewer system on most urban construction sites. ;~ Eliminates flooding and standing water due to its built in high water overflow. f- M Can be used as temporary or permanent control which can be easily relocated and reused, making it temporary protection you only pay for once. Patent # 5,405,539 For more rnormation caB 800-891-0473 For More Information. Circle #30 Uu1d and Water ~~_"""","'f.:._':;>t.~;:"'-'-" "."'. March/April 1996033