WSP00787

• File Number: 8583
• Description: Rio Grande Decision Support System
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 10/1/1997
• Author: Davis Engineering Se
• Title: Report On Groundwater Recharge And Management Project - RGDSS
• Water Supply Pro - Doc Type: Report/Study

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EXECUTIVE SUMMARY
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This project was in~i~tea~y the San Luis Valley Water Conservancy District for the purpose of
collecting data that would provide a better understanding of the mechanism benefits of ground
water recharge in the SanLuis Valley of Colorado and to construct a major recharge structure to
facilitate ground water storage with winter surface diversions. The District obtained funding
assistance from the Colorado Water Conservation Board and obtained contributions consisting of
equipment and drilling of monitoring wells from the Colorado State Engineer's Office and
U.S.D,1. Bureau of Reclamation.

A major recharge structure to improve recharge with winter surface diversions was constructed.
The facility was constructed northeast of Del Norte and is designed to receive water from the Rio
Grande Canal. A map showing the location of the facility and some construction details is
included as Figure E.S,-I,

Ground water levels in monitoring wells at the recharge site northeast of Del Norte were
measured frequently for approximately three years. Ground water levels consistently rose during
periods when surface recharge was available and declined when water was not available.
Evidence was collected indicating a large portion of the ground water recharge at this site enters
the artesian or confined aquifer that underlies a large portion of the San Luis Valley. Ground
water level measurements at a site near the central portion of the Valley north of the Rio Grande,
indicates surface recharge significantly increases water storage in the shallow unconfined aquifer.

Recharge potential in the San Luis Valley was investigated by studying aquifer properties and
depths to ground water. A map was prepared that provides information that can be used as a
guide by ground water users to determine the size of recharge pit and length of time recharge is
necessary at their location to replace groUnd water pumped. This map is included as Figure
E.S.-2.

The study identified numerous canal and ditch systems that divert water for the purpose of
ground water recharge in the San Luis Valley. A review of depths to ground water indicated that
available storage space in the under ground aquifers is not used in an optimum manner. Tasks
that a water management agency could perform to improve ground water recharge were
described. These tasks varied from reporting on ground water conditions to actual management
of canal and ditch systems.

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