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<br />Hydrology
<br />
<br />Hydrologic analysis included the developmenr of hydrologic models
<br />based on existing (circa 2005) and future (circa 2025) land use con-
<br />ditions to generate flood hydrographs and estimate peak discharges
<br />at selected concentrations points rhroughour the watershed. This
<br />was completed to evaluate existing and future stotm Rows that result
<br />from a range of storm events (2, 5. 10, 25, 50, 100, 500 year and 24
<br />hour storm events). As such, the study focused on stormwater runoff
<br />and not baseBow. 'Ihe 2-year Bood flows are significam because the
<br />small, frequently recurring stOrm events are most responsible for
<br />shaping the channel and moving the most sediment ovcr time. 'The
<br />1 OO-year flood flows are significant because this flow is typically the
<br />basis for establishing rcgulated Boodplains. 111e most pronounced
<br />changes in /low, when comparing existing and future conditions, arc
<br />expected to occur along:
<br />Jimmy Camp Creek
<br />East Fork Sand Creek
<br />Monument Crcek and east tributaries (Monument Branch,
<br />Elkhorn Tributary, Tcachout Creek and Black Squirrel Creek)
<br />Cottonwood Creek
<br />Fountain Creek mainstem
<br />
<br />Comparing existing and future modeled peak discharges for
<br />Fountain Crcek at the confluence with the Arkansas River shows
<br />that flow volumc is expected ro increase by 25% for the 2-year storm
<br />and about 10% for the Ion year event. Figures are available on www.
<br />fountain-crk.org that show specific locations where changes in peak
<br />discharge and/or flow volume is expected to be greater then 10%
<br />from existing to future conditions.
<br />
<br />Hydraulics
<br />
<br />Hydraulics were completed to evaluate /low characteristics (e.g.
<br />depth and velocity) for existing and future stream flows that result
<br />from a range of storm events. 'Ille focus of this modding was the
<br />preparation offlood profilcs and for use in the sediment transport
<br />anaIysis. As part of the hydraulic analysis, a total of 314 structures
<br />(e.g. bridges, major culverts, detention ponds, improved channels
<br />and drop structures) were surveyed and included in the model.
<br />Twcnty one streams were selected for hydraulic analysis. Summary
<br />results for each stream include tables with average channel velocity,
<br />avcrage flow depth, water surf:1ce elcvation profiles and cross section
<br />plots.
<br />
<br />Geomorphology Analysis
<br />
<br />Geomorphology analysis was completed ro document existing chan-
<br />nel conditions, evaluatc channel characteristics (e.g. cross section
<br />dimension, platform patterns, profile), assess relative stability and
<br />completed sediment transport modeling. 'Ihe Foulltain Creek trends
<br />from the study indicated:
<br />Changes due to channel meandering and lengthening.
<br />Wavelengths getting shorter overall.
<br />Radii getting shorter overall.
<br />Channel straightening has lead to shorter segments for
<br />Cottonwood Creek, Monument Creek, Sand Creek, E. Fork
<br />Sand Creek, and Jimmy Camp Creek. Channel straightening
<br />was human induced, with the exception of Jimmy Camp Creek.
<br />
<br />The most significant decreases in challnellength (more than 10%
<br />from 1955 to 2003) occurred in the northern part of the watershed.
<br />'Ihe most significant increases in channellcngth occurred in the
<br />mainstem of l:ountain Creek.
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<br />Recommendations
<br />
<br />Project sponsors and stakeholders have completed evaluating
<br />the U.S. Army Corps of Engineers Study rccommendations for
<br />site specific projects and are in the process of evaluating general
<br />recommendations.
<br />
<br />Specific Projects
<br />
<br />A spreadsheet of prioritized projects and thc location of the 13
<br />projects that will be further evaluated arc shown on the next page.
<br />Project typcs were identified as flood risk reduction, ecosystem resto-
<br />ration or channel stability. To prioritize projects, the Corps assigned
<br />points based on criteria developed for each project type. COSts for
<br />the projects were categorized as low, medium or high and funding
<br />sources identified as either local or through a State or Federal agency.
<br />Most State agencies or Federal agencies such as the Corps have cost
<br />sharing available through specific program authorities. Although
<br />prioritization of the projects was used to determine which projects
<br />are further evaluated, any project on the list can be used to apply for
<br />further funding.
<br />
<br />General Recommendations
<br />
<br />. As part of the Corps Study, 17 general recommendations were made,
<br />primarily dealing with policies such as development and drainage
<br />that could allect erosion, sedimentation and flooding in the water-
<br />shed. 'I11ese general recommendations are ill the process of being
<br />evaluated and once finalized will be posted at www.founrain-l.:rk.org.
<br />It would be the responsibility of each city or coulHy or other agencies
<br />to implement the recommendations.
<br />
<br />Next Steps and Timeline
<br />
<br />Activity Description Date
<br />Pruject Evaluatiun Cumplete field visilS Jnd February 2008
<br /> evaluation of cost and
<br /> pwjeet feasibility of wf'
<br /> 10 sites.
<br />General Finalize general reCOm- March 2008
<br />Recommendatiom Illendatiom of sllIdy
<br />Public Meeting.' I'ublk input on project May 2008
<br /> recommend,t ions
<br />Draft Report Cumplerion of Draft May 2008
<br /> Report
<br />Project Completion Final completion of September 2008
<br /> project
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<br />Beaver dams on Upper Monument Creek near Monument.
<br />Photo COllrteS)' of lJRS Corporation.
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