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<br />Chatfield Reservoir
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<br />Chapter 3 - Mitigation Plan
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<br />This section presents conceptual designs for the relocation and redevelopment of park facilities that would
<br />be impacted by raising the water level of Chatfield Reservoir, As previously discussed, impacts to park
<br />facilities and programs were based on a future normal high water elevation of 5444 feet. Major facilities,
<br />such as buildings and main roadways, which had to be relocated or redeveloped, were located above the 5444
<br />elevation and provided with an additional buffer of two vertical feet, i,e, a base elevation of 5446,
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<br />Based on prior modeling (Brown and Caldwell, 2003), the reservoir was assumed to be drawn down to an
<br />elevation of 5436 during a normal year, The water elevation could also drop below 5436 in extreme drought
<br />conditions, which could result in the temporary closure of some facilities,
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<br />Any facilities or use areas that fell below, or close to, elevation 5444 were evaluated for replacement or
<br />adjustment. In some cases, an existing parking area or boat ramp would only need to be partially modified to
<br />accommodate the future water level.
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<br />An important assumption that guided the conceptual design effort was that no facility or program area would
<br />loose any capacity or functionality as the result of relocation or modification, Put another way, the mitigation
<br />plan provides for in kind replacement of facilities affected by higher water levels, Design and development
<br />of replaced facilities would be completed under current building codes, Colorado State Parks building
<br />requirements, and to meet American Disability Act (ADA) requirements for public facilities,
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<br />It must be emphasized that the mitigation plan reflects a conceptual level of design, More detailed design
<br />will be required to address site-specific conditions and other design factors. Among these, is the need to
<br />base the design on final reservoir operations modeling so that facility locations and features reflect the actual
<br />drawdown conditions that are anticipated after the reallocation project is further refined,
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<br />Costs for implementing the recreation mitigation plan are presented in Chapter 4, A key assumption in
<br />developing the mitigation plan is that fill material will be available from on site sources and that this material
<br />can be obtained from locations below the high water line,
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<br />During preliminary stages of this study, design altematives were considered at varying levels of detai I.
<br />Following review and discussion with Colorado State Parks and other study participants, a preferred concept
<br />was identified for each major use area, Only the preferred concept is presented in this report,
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<br />EDAW February 2004
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<br />Recreation Mitigation Study
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<br />North Boat Ramp
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<br />Elevation 5444 results in partial inundation of this facility, with ramps becoming inoperable,
<br />Facilities affected include boat ramps, parking area, day use shelters, and trails,
<br />Boat ramps would be constructed to extend to the elevation of the existing ramps in order to operate at
<br />low water levels, The gradient (slope) on the new ramps would be reduced,
<br />Day use shelters and furniture would be relocated as would trails,
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<br />This alternative requires a substantial amount of fill to raise the parking area,
<br />The resulting concept is illustrated in Map 3, I.
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<br />Massey Draw Day Use Area
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<br />Raising the water level to 5444 severely reduces the recreation capacity of this area but does not
<br />inundate the existing parking area and restroom,
<br />Mitigation to this area would include importing fill material to raise the elevation above 5444 and
<br />create a usable recreational area in the same location with a similar amount of usable area that currently
<br />exists, Existing beach volleyball, and horseshoe pits would be rebuilt. Furniture can be stored and
<br />relocated to future area,
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<br />The resulting mitigation concept is illustrated in Map 3,1
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