Prairie Ditch and San Luis Valley Canal San Luis Valley, Colorado
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 groundwater 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 groundwater 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 groundwater recharge, is crucial to sustaining the
shallow groundwater reservoir that allows the continuing operation of their
center pivot sprinkler systems. To this end, Company shareholders have
constructed groundwater recharge facilities to artificially recharge
groundwater.
Deere & Ault 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 the companies' historic 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 also performed a hydrologic analysis of the Closed Basin,
updating the location of the groundwater divide. Deere & Ault staff
provided expert witness testimony on the Prairie Ditch Case, which was
settled in late-2001. The San Luis Valley Canal Case has been decreed.
Client: Prairie Ditch Company and San Luis Valley Canal Company
