BOARD00059 ‎(3)‎

• Board Meeting Date: 1/23/2007
• Description: WSP Section - Litigation Account Status Report - Kansas v Colorado, Arkansas Basin Studies and Activities - Colorado River Activities
• Board Meetings - Doc Type: Memo

method and then be used to detennine Penman-Monteith crop coefficients for other major
crops grown in the Lower Arkansas River Basin.

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Plans for the design of the larger Iysimeter to be constructed at Rocky Ford were
(~eveloped and peer reviewed using funds provided by the State Engineer's Office and by
the Colorado Water Resources Research Institute. The use of CWCS funds began with
the initiation of the fabrication of the two large steel tanks that comprise the majority of
the Iysimeter structure. This fabrication was done at the USDA Agricultural Research
Service metal shop in Ft. Collins and was star1ed in August, 2005. Construction
operations for the larger Iysimeter were initiated at Rocky Ford in November, 2005 with
the acquisition of the undisturbed soil monolith and completed in August, 2006 with final
replacement of tillable soil around the top portion of the Iysimeter. The installation of
electronic equipment into the Iysimeter began in August, 2006 and the Iysimeter was
caljbrated in October, 2006. Installation and testing of the remaining electronic
equipment and sensors is currently being completed and the first planting of an alfalfa
crop is planned for late February, 2007. During the current winter season, this Iysimeter
has been collecting data to be used in a study of evaporation losses from bare agricultural
soil during the non-irrigation season.

Plans for the design of the smaller reference Iysimeter are currently being completed.
Peer review of these plans and the detemlination of a detailed cost estimate for the
construclion of this Iysimeter will take place in February, 2007.

CoAgMet Enhancement

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The objective of this project is to enhance and improve the CoAgMet electronic weather
station network in the Lower Arkansas River Basin and provide for its adequate operation
and maintenance in order to provide accurate data for predicting evapotranspiration using
the Penman-Monteith method.

From a starting point of six automated CoAgMet weather stations in the Arkansas Valley
in 2004 in a mixture of ilTigated, near-irrigated and dryland environments, the network
was increased to eleven unifollllly spaced stations with the majority positioned within
irrigated areas. Since initial installation, each site has been well maintained, data
communications hardware have been upgraded, and instruments have been checked,
serviced and calibrated on a regular schedule. All data have been reviewed and quality
controlled resulting in dramatic improvements in data quality, spatial representativeness
and availability for assessing evapotranspiration rates throughout the Valley. All data are
updated daily and available through the Colorado Climate Center's website at Colorado
State University.

Monitoring of Irrigation Amount, Timing, and Crop Yield

The objective of this project is to conduct studies in the Arkansas River Valley to
determine adjustments for irrigation management and salinity effects that should be made
to predictions of evapotranspiration using the Penman-Monteith method.

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