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<br />002435
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<br />and unit duration at one point in this channel wi 11 result in a specific flow
<br />response, or unit response, .at a downstream location. The method has been
<br />used successfully for a number of streams. For the Vampa River basin, the
<br />method might be used to simulate daily discharge at sites where data,of short
<br />duration are available using upstream or downstream s'ites with longer records.
<br />For most cases, a common data period to both sites will be used to cal ibrate
<br />the model parameters,
<br />
<br />After a uniform data base has been established for several locations,
<br />streamflow can be estimated at locations where data are not available, This
<br />is accompl ished by reapplying the unit-response routing technique, or by using
<br />basin-characteristic relationships, As an alternative or supplemental method,
<br />selected streamflow records of short duration may be extended using correla-
<br />tion procedures described by Fiering (1963), and Matalas and Jacobs (1964),
<br />These procedures may improve the population estimates of the mean and variance
<br />of streamflow data. This would be helpful in evaluating the'potential use and
<br />benefits of additional storage reservoirs and for determining benefits of ad-
<br />ditional streamflow data.
<br />
<br />!/eservo.ir modeZing,--Several small reservoirs are located on tributaries
<br />of the Vampa River, Generally, these were built' for recreation, livestock Wa-
<br />tering, and irrigation, There are numerous reservoirs in the planning stages
<br />which have intended uses of irrigation, hydroelectric power, and cooling water
<br />for power plants. The present reservoirs are operated with uncontrolled over-
<br />flow structures, whereas some of the larger planned reservoirs will be oper-
<br />ated with release schedules designed to optimize power !;jeneration or irriga-
<br />t i on use,
<br />
<br />The hydrologic effects of selected present and planned reservoirs having
<br />capacities of 5,000 acre-feet (6.2xl06 m3) or more will be simulated during
<br />the basin assessmen~. Plans include the use of reservoir-routing techniques
<br />described by Rutler and Engstrom (1964) to simulate flow conditions downstream
<br />from the reservoir for natural and controlled conditions. There are several
<br />operational reservoir-routing model programs now available which could be used.
<br />Program HEC-3, developed by the U,S, Army Corps of Engineers (1968), Hydrolog-
<br />ic Engineering Center, and SIMVLD-ll, developed by the Texas Water Development
<br />Board (1972), are two that will be considered, Both models are designed to
<br />simulate a system of reservoirs subject to a specified hydrology and time se-
<br />quence of demands. In most cases, the models operate on a monthly-increment
<br />flow basis. Both models also allow the input of existing or planned oj)erating
<br />schedules for the reservoirs, In addition, the HEC-3 program can consider re-
<br />lease schedules for reservoirs to be operated for power generation,
<br />
<br />Models also exist that could be used to study the operation of individual
<br />reservoirs, For some of the stream reaches, the reservoir models will be com-
<br />bined with the stream models, previously described, to generate streamflow
<br />data at some desired downstream location,
<br />
<br />SnowmeZt-runoff modeZing.--The dominant part of streamflow in the Vampa
<br />River basin is contributed by snowmelt runoff from the mountainous areas in
<br />the eastern part of the basin. Snowmelt occurs consistently between late
<br />April and early July, with the highest monthly flows occurring during May and
<br />June. W, V, Tangborn (U.S. Geological Survey, Tacoma, Wash,) currently is
<br />applying snowmelt-runoff model ing techniques to the upper Vampa River basin
<br />
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