PUB00027

• Year: 1990
• Title: Final Report Rio Grande Water Supply Study, Phase 1
• CWCB Section: Interstate & Federal
• Author: San Luis Valley Water Conservancy District
• Description: Reconnaissance level determination of the physically and legally available flow at 4 reservoir sites in the Rio Grande Basin upstream of Del Norte, Colorado
• Publications - Doc Type: Brochure

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as the calibration period since it represents a time in which mainstem water

rights were unencumbered by active administration of the Rio Grande Compact.

For each of the two mainstem diversion scenarios, five storable flow simulations

were performed with the river basin model. A base simulation was performed which

estimated storable flow at the Wagon Wheel Gap site for each of the two mainstem

diversion scenarios if no Closed Basin Project deliveries were made. Subsequent

simulations estimated storable flows at the four damsites with Closed Basin

Project deliveries.

Results

The results of the storable flow analyses at the four potential reservoir sites
are summarized below.

There was little opportunity to exchange Closed Basin Project Priority Three

water to a new storage vessel upstream of Del Norte. For the Step One

mainstem diversion scenario, it is estimated that the exchange ability

approximates 3,000 af on an average (1948-1985) annual basis. For the

Alternate Step Two mainstem diversion scenario, the exchange ability

approximates 1,000 af on an average (1948-1985) annual basis. The

opportunity to exchange Closed Basin Project water to a potential reservoir

site typically occurred in less than half of the years of the study period.

The primary reason for the limited exchange ability is that the periods

in which there was adequate streamflow for exchange did not coincide with

availability of Priority Three water. For example, in many above average

runoff years, there was adequate streamflow for an exchange but most of

the production capacity of the Closed Basin Project would be used for

Priority One requirements. This is due to the fact that Compact delivery

requirements are greater in above average runoff years.

Storahle Flood Flows occurred in only two years of the 38 year study period

for the Step One mainstem diversion scenario. Storable Flood Flows

approximated 75,000 af in 1948 and 30,000 af in 1985. No Storable Flood

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