RGDSS_Historic_CUreport_20040601

• Title: RGDSS - Rio Grande Historic Crop Consumptive Use Analysis
• Description: The documentation is for the Rio Grande Basin Historic Crop Consumptive Use Analysis, developed during the RGDSS implementation for the period 1950 through 2002. It includes 100 percent of the crop consumptive use in the basin for the period. Documentation consists of the final Historic Crop Consumptive Use Analysis Report and supporting appendices.
• Decision Support - Doc Type: Modeling Dataset Documentation
• Date: 6/1/2004
• DSS Category: Consumptive Use
• DSS: Rio Grande
• Basin: Rio Grande
• Contract/PO #: C153863
• Grant Type: Non-Reimbursable
• Bill Number: HB98-1189, SB99-173
• Prepared By: Leonard Rice Engineering

5.5 Surface Water Model Planning Scenario
The RGDSS surface water model planning scenario includes diversions from Costilla
Creek that irrigate lands in New Mexico. An estimate of consumptive use for these lands
is required for the surface water modeling effort. The additiona14,960 acres associated
with these lands results in total scenario irrigated acreage of 627,828 acres for 1998.
Tables 21a and 21b show the average annual consumptive use water budget for the
surface water model planning scenario. As shown, the 1950 through 2002 average
annual crop consumptive is 4,126 acre-feet more than the historic consumptive use
analysis results in Colorado only.
Table 21a
Surface Water Model Planning Scenario Results 1950 through 2002 (acre-feet)
Surface Water Diversion Accounting
Irrigation River Surface Water Diversion To: Calculated
Water
Required Headgate
Diversion Conv
Loss Diversion
to Farm
CU
Soil Non-
Consumed Application
Efficiency
1,129,191 1,088,170 343,273 751,443 348,807 50,336 352,301 53
Table 21b
Surface Water Planning Scenario Results 1950 through 2002 (acre-feet) -Continued
Ground Water Diversion Accounting Estimated Crop C U
Diversion
(Pum in) Application
Efficienc To CU Non-
Consumed From SW
and GW From
Soil Total Total Non-
Consumed
542,945 67 % 364,570 178,375 713,377 49,793 763,171 530,675
5.6 Ground Water Model Planning Scenario
The RGDSS ground water model covers the area overlying the aquifer systems in the San
Luis Valley. A subset of the basin historic consumptive use analysis was developed for
the RGDSS ground water modeling effort. 601,196 irrigated acres were identified within
the ground water model area during 1998. This is approximately 96.5 percent of the
622,868 acres used in the historic crop consumptive use analysis for the basin in
Colorado. Tables 22a and 22b show the average annual consumptive use water budget
for the ground water model scenario. As shown, the 1950 through 2002 average annual
crop consumptive use is 730,836 acre-feet within the ground water model area.
cureport_6-2004.doc 45 of 48 June, 2004