The lands served by the Prairie Ditch and San Luis Valley Canal lie largely within what is known as the “Closed Basin.” The Closed Basin occupies the northern portion of the San Luis Valley, and is separated from the Rio Grande’s alluvial valley by a low topographic divide and a shallow ground water divide oriented roughly parallel to the river. Water imported into the Closed Basin does not naturally return to the Rio Grande.
Surface water is diverted from the Rio Grande into the Closed Basin for recharge of a shallow aquifer.
The ground water is subsequently pumped from the aquifer and used to irrigate crops.
The Prairie Ditch and the San Luis Valley Canal Companies recognize that continued importation of direct flow surface water from the Rio Grande, in conjunction with ground water recharge, is crucial to sustaining the shallow ground water reservoir that allows the continuing operation of their center pivot sprinkler systems. To this end, Company shareholders have constructed ground water recharge facilities to artificially recharge ground water.
Deere & Ault Consultants, Inc. staff performed an investigation of the historical water use practiced by the Prairie Ditch and San Luis Valley Canal Companies. The objectives of this investigation were to confirm their historical practice of recharging the unconfined aquifer of the Closed Basin, and to present a methodology and accounting procedure to quantify the volume of recharge to the unconfined aquifer of the Closed Basin from their water rights.
Deere & Ault staff also performed a hydrologic analysis of the Closed Basin, updating the location of the ground water divide and provided expert witness testimony on the Prairie Ditch Case, which was settled in late-2001. The San Luis Valley Canal Case was decreed in 2003.
Client: Prairie Ditch Company and San Luis Valley Canal Company, Colorado