30 ‎(3)‎

• Board Meeting Date: 5/21/2008
• Description: IWMD Section - Presentation of Agricultural Water Conservation Paper
• Board Meetings - Doc Type: Memo

Section 2
Introduction
2. Water conservation options that result in additional water from irrigated
agriculture are limited to those that reduce evaporation or crop consumptive uses.
As a result, management practices that result in improved irrigation efficiency do
not necessarily yield transferable supplies. Diverted water that is not consumed
by senior appropriators belongs to the stream system and thus other water right
holders.
3. Wide-scale adoption of water conservation practices designed to increase
diversion of f iciencies has the potential of altering basin hydrology by reducing the
magnitude and timing of return f lows.
4. Another possible unintended consequence of basin-wide increases in diversion
efficiency is increased consumptive irrigation water use. This would occur as a
consequence of irrigators, operating within their decrees using the conserved
water from more efficient diversions to fill shortages. Increased consumptive use
would of f ect basin hydrology and eventually result in reduced return f lows.
Conversion to improved irrigation efficiency systems, e.g., flood to sprinklers,
may result in an increase in consumptive use.
5. The potential f or f uture agricultural water conservation in Colorado varies greatly
among basins. More importantly, policy initiatives designed to encourage
conservation should be based on how water is used at the basin level rather than
at the individual f arm level. Also, impacts of water conservation strategies on
interstate compact obligations must be considered.
6. Much of the irrigation inf rastructure in our river basins dates from the late 1800s
and could benefit from upgrading. However, under current water law, there is
little personal incentive f or irrigators to invest in upgrading irrigation
infrastructure.
7. Major canals that are currently unlined support extensive vegetation resulting in
significant conveyance losses in the f orm of non-crop consumptive use.
Many other reports and studies have concluded that opportunities to provide f or
meeting future water supply needs with agricultural water conservation measures are
limited and potentially can result in injury to vested Colorado water rights, wetlands,
groundwater levels, and streamflows. These reports, which have been used in
developing this paper, include:
Memorandum to South Platte Task Force. Anne Castle and Bill Caile, Holland and
Hart. July 12, 2007.
SWSI Phase 2 Technical Round Table Report on Alternatives to Permanent
Agricultural Dry-up prepared for the Colorado Water Conservation Board. CDM
(Camp Dresser & McKee Inc.). November, 2007.
DRAFT 2-3