Simulated Effects of Proposed Southern Delivery System Alternatives on Hydrodynamics and Water Quality of Pueblo Reservoir Using a Two-Dimensional Hydrodynamic and Water-Quality Model, Pueblo, Colorado

Science Center Objects

Pueblo Reservoir is one of southeastern Colorado's most valuable water resources. The reservoir provides irrigation, municipal, and industrial water to various entities throughout the region. The reservoir also provides flood control, recreational activities, sport fishing, and wildlife enhancement to the region.

The Bureau of Reclamation is working to meet its goal to issue a Final Environmental Impact Statement (EIS) on the Southern Delivery System project (SDS).  SDS is a regional water-delivery project that has been proposed to provide a safe, reliable, and sustainable water supply through the foreseeable future (2046) for Colorado Springs, Fountain, Security, and Pueblo West. Discussions with the Bureau of Reclamation and the U.S. Geological Survey led to a cooperative agreement to simulate the hydrodynamics and water quality of Pueblo Reservoir. 

This study compared simulated hydrodynamics and water quality for projected demands in Pueblo Reservoir resulting from changes in inflow and water quality entering the reservoir, and from changes to withdrawals from the reservoir as projected for the year 2046.

Four of the seven EIS alternatives were selected for scenario simulations. The four U.S. Geological Survey simulation scenarios were:

  • EIS Alternative 1: the No Action scenario
  • EIS Alternative 2: the Downstream Diversion scenario
  • EIS Alternative 4: the Upstream Return-Flow scenario
  • EIS Alternative 7: and the Upstream Diversion scenario

Additionally, the results of an Existing Conditions scenario (water years 2000 through 2002) were compared to the No Action scenario (projected demands in 2046) to assess changes in water quality over time. All scenario modeling used an external nutrient-decay model to simulate degradation and assimilation of nutrients along the riverine reach upstream from Pueblo Reservoir.