PROPOSED DEVELOPMENT OF RESERVOIR The principal attribute of the proposed Rueter-Hess Dam and Reservoir is that it will store water from various renewable sources in the reservoir and these supplies will then be managed to obtain increased utility of the resource. The size of the dam and reservoir to accommodate these objectives will be a 135-ft high dam, 5,300 ft long, and will inundate approximately 470 surface acres and would impound approximately 16,200 ac-ft. Rueter-Hess Reservoir Dimensions Dam Height 135 feet Capacity 16,200 acre-feet Reservoir Footprint 470 acres Dam Length 5,300 feet The estimated time line for construction of the dam, based on the lead time necessary for permitting, assumes that the dam and reservoir will be on line by 2005. ANCILLARY FACILITIES Beyond construction of the dam, there are several ancillary facilities that will need to be constructed to make the Rueter-Hess Reservoir operational. In-priority Cherry Creek flows can be captured and delivered to Rueter-Hess Reservoir via two means. The first will be Rueter-Hess Reservoir Aqueduct No. 1, which envisions a pipeline manifolded to several alluvial wells completed along Cherry Creek in the reach that the District controls (from Section 34 of Township 6 South, Range 66 West, to Section 9 of Township 6 South, Range 66 West). Creek elevations in this reach range from approximately 5,875 ft MSL at the upstream end to 5,750 ft MSL at the downstream end of the reach. It is envisioned that the alluvial well pumps will be sized such that the submersible pumps will be capable of moving the water from the alluvial wells to Rueter-Hess Reservoir. Rueter-Hess Reservoir Aqueduct No. 2 envisions a diversion structure on Cherry Creek in Section 34 of Township 6 South, Range 66 West. This diversion structure will be located at an approximate stream elevation of 5,900 feet MSL, and will have to be lifted over a high point at elevation 6,250 ft MSL prior to being released into a tributary which flows into Rueter-Hess Reservoir. Once water stored in Rueter-Hess Reservoir is desired to be used, it will be decanted from the structure and routed to a water treatment plant located adjacent to the dam. This water treatment plant will process the water to potable standards, and the water will then be pumped into the District’s distribution system, or will be injected into the Denver Basin aquifers for underground storage. Alternatively, Rueter-Hess Reservoir can be used to provide supplemental stream flow, whereby raw water can be released (to Newlin Gulch), or pumped back to Cherry Creek and allowed to flow downstream for subsequent use. OPERATIONAL PLAN There are several potential sources of water that can be stored in Rueter-Hess Reservoir. These include both in-basin sources and potential imported water from other basins. In-basin sources include: Diversion of the District’s existing tributary Cherry Creek water rights through alluvial wells; Diversion of in-priority Cherry Creek surface flows; Diversion of in-priority Newlin Gulch surface flows; Diversion, by exchange of the re-usable effluent from the District’s AWT plant; and Irrigation return flows. A schematic showing the District’s proposed operational philosophy. Any operational plan associated with the Rueter-Hess Reservoir will be contingent upon the volume and timing of water supply sources. Because of the variables, no specific operational plan can be developed at this time, but general operating philosophies can be enumerated which likely will be followed at the reservoir. Based on this, the general operational philosophy for Rueter-Hess Reservoir will be as follows: The reservoir will be operated consistent with the Douglas County Water Resource Authority Resolution, which calls for the maximization of in-basin resources, including conjunctive use. Rueter-Hess Reservoir Conjunctive Use Project Project proposes the coordinated use of surface water and ground water sources and facilities to produce a larger and more reliable combined supply, including storage of wet year surplus supplies in surface storage plus bedrock aquifer artificial storage and recovery. In-priority Cherry Creek surface flows, as well as diversion from Cherry Creek alluvial wells, will be maximized to the extent possible. It is envisioned that a forebay would be used on Cherry Creek to allow the diversion of high-flow, low-duration flows in an efficient manner. Alluvial wells, and potentially Ranney collectors, could be used to supplement waters diverted into the forebay. The reservoir will be built to a capacity to allow sufficient carryover storage to hold the periodic in-priority flows described in (2) above. Effluent from the AWT process will be released to Cherry Creek and an equivalent volume will either be pumped to the reservoir or will be used directly. This storage of effluent by exchange in the wintertime months can then be used for peaking requirements in the summertime months. An ancillary benefit of this mode of operation is that phosphorus input to Cherry Creek and ultimately to Cherry Creek Reservoir would be minimized. Denver Basin well fields will be established in the vicinity of Rueter-Hess Reservoir to allow a conjunctive use plan whereby excess surface water can be injected into the Dawson and Arapahoe aquifers to utilize these underground storage vessels. This conjunctive use plan will take place during times when excess surface water supplies are available that can’t be stored in the Reservoir due to space limitations. As the plans for Rueter-Hess Reservoir crystalize, the operational plan will be tailored to optimize the water yield from the reservoir. CONCLUSIONS The following conclusions have been drawn from the work done at Rueter-Hess Dam and Reservoir to date: Rueter-Hess Reservoir will provide a long-term, reliable water supply storage for the District. There are sufficient in-basin water supplies to justify the construction of Rueter-Hess Reservoir, including (a) in-priority Cherry Creek flows, (b) advanced wastewater treatment effluent return flows, (c) in-priority Newlin Gulch flows, and (d) lawn irrigation return flows. The reservoir can serve multiple purposes, including (a) direct use for municipal water supplies, (b) provide carryover storage that provides reliable yield in dry years, and (c) serve as a source for bedrock aquifer injection. Both the environmental and geotechnical studies necessary to get to the construction phase are already under way, and none of these studies has indicated fatal flaws which would preclude the development of the project.
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