C153954 Contract

• Contract/PO #: C153954
• Contractor Name: Leonard Rice Consulting Water Engineers
• Contract Type: Grant
• Water District: 0
• Loan Projects - Doc Type: Contract Documents

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RGDSS. General information from the Colorado Irrigation Guide will be considered as a
source for estimating local crop growing seasons.

Deliverables:

54.1 Acreage and crop type data in the requested digitized format to the HydroBase data
manager for storage plus a memorandum describing the data source, contact name, and
data formatting requirements.

54.2 A memorandum describing the changes over time by county and basin. The
memorandum will include a recommendation for crop categories, by county and historic
period, to use in the irrigated acreage assessment.

Task 58 . Review Previous Estimates of Potential CU

Objective:

Review and document previously generated estimates of potential crop consumptive use in the
SPDSS study area for verification and comparison purposes for the different modeling time
periods.

Approach:

58.1 Gather appropriate data and literature from previous studies of potential and supply-
limited crop consumptive use in the South Platte and North Platte River basins. Sources
for data include the USGS, the USBR, CSU, LRE's library, and LRE's collection of
water right transfer decrees and supporting engineering reports. In addition, supporting
documents from other key court cases will be identified and reviewed.

Deliverables:

58.1 A draft memorandum summarizing historic CU estimates and techniques. The
memorandum will include maps showing the geographic areas represented by the
estimates.

Task 59, 60, 61, and 73 . Collect Applicable Information, Develop Locally Calibrated
Blaney-Criddle Coefficients, and Estimate Potential CU at Climate Stations

Background:

The modified SCS Blaney-Criddle consumptive use methodology estimates potential
consumptive use on a monthly basis using monthly average temperature and daylight hours.
Because this data is readily available for long study periods, the methodology is widely used and
recommended for use in the SPDSS. However, Blaney-Criddle crop coefficients available from
the SCS publication Irrigation Water Requirements Technical Release No. 21 (TR-21) were
developed to represent general conditions around the west and may not represent local conditions
in the South Platte or North Platte River basins. Therefore, consistent with the approach taken
for RGDSS, locally calibrated Blaney-Criddle crop coefficients will be developed for SPDSS.
Because of the relatively large extent of the SPDSS study area, up to three locally calibrated
coefficients may be required and developed for each major crop type.

SPDSS Consumptive Use and Water Budget Component

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