Stochastic Modeling of Effects that the Sulphur Gulch Reservoir May Have on Colorado River Water Quality near Grand Junction, Colorado

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Sulphur Gulch, a new reservoir proposed to be located about 25 miles east of Grand Junction, Colorado, on a tributary to the Colorado River that drains the Sulphur Gulch watershed between De Beque and Cameo, Colorado. The primary use of the Sulphur Gulch Reservoir would be to provide the Colorado River with up to 5,412.5 acre-feet of late-season water in support of the Endangered Fish Recovery Program.

Presently, there is concern that development and operation of the Sulphur Gulch Reservoir may change the water quality of the Colorado River at Palisade, Colo.

Understanding the operational effects that Sulphur Gulch Reservoir may have on water quality at Palisade is important because:

  • this location represents the upstream end of the 15-mile reach where several endangered fish species reside
  • and control of salinity in the Colorado River is a priority.


    1. To modify and expand the existing annual mixing model to incorporate natural variability and uncertainty for evaluation of stream salinity on a daily time step at locations along the entire study reach,
    2. To quantify the effect of modeled natural variability and uncertainty on probable changes in stream salinity subject to selected reservoir fill and release scenarios,
    3. To determine reservoir parameters that minimize adverse water-quality effects during release to the Colorado River using a suitable optimization technique, and
    4. To make an initial assessment of the potential for selenium loading at the Sulphur Gulch Reservoir site.