BOARD00078 ‎(2)‎

• Board Meeting Date: 11/13/2006
• Description: CF Section - Referred Non-Reimbursable Investments - Central Colo. Water Conservancy District - Estimate of Deep Percolation from Irrigation to South Platte Alluvial Aquifer in Northern Colorado
• Board Meetings - Doc Type: Memo

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ST ATE OF COLORADO

Colorado Water Conservation Board

Department of Natural Resources
1313 Sherman Street, Room 721
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
www.cwcb.state.co.us

MEMORANDUM

Bill Owens
Governor

Russell George
Executive Director

To: Colorado Water Conservation Board Members

Rod Kuharich
CWCB Director

From: Bruce Johnson, P.E. ~ ~~ f
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Dan McAuliffe
Deputy Director

Date: November 3, 2006

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Re: Non-Reimbursable Investment - Agenda Item 1~
Central Colorado Water Conservancy District:
Estimation of Deep Percolation from Irrigation
to the South Platte Alluvial Aquifer in Northern Colorado

Introduction
This request is for funding to study deep percolation from irrigation along the South Platte River, to
be conducted by the Central Colorado Water Conservancy District (CCWCD) and the U.S.
Geological Survey (USGS). The purpose of the study is to develop an improved understanding of
return flow to the tributary system through deep percolation from irrigation, thereby assisting in
water-allocation management throughout the region. For FY 07-08, an appropriation of$150,000 is
being sought from the Construction Fund.

Discussion

This research study is intended to supply data that will enhance water allocation management
throughout the region by connecting the efficiencies of irrigation techniques, and their subsequent
aquifer recharge, to different soil types. Employing bromide tracing and water-level monitoring,
deep percolation will be estimated beneath fields at three farmland test sites in CCWCD,
representing three different irrigation methods (sprinkler, flood and drip irrigation). When
completed, the research will be use to determine on-farm consumptive use figures and will influence
management of irrigation resources in Northern Colorado.

At the September Board Meeting several questions were raised. In October, Staff met with CCWCD
and USGS representatives to discuss these questions and the study in general. In summary,
questions raised by the Board were:

Flood Protection. Water Supply Planning and Finance. Stream and Lake Protection
Water Supply Protection. Conservation and Drought Planning