Section3_AgricultureWithTables

• Title: SWSI Phase 2 Report - Alternative Agricultural Water Transfer Methods to Traditional Purchase and Transfer
• Date: 11/7/2007
• Author: CWCB
• SWSI II - Doc Type: Final Report

Section 3
Alternative Agricultural Water Transfer Methods to Traditional Purchase and Transfer
The matrices presented in Section 3.9 describe
where certain techniques may have the best
applicability. For example, ISAs offer long-term
opportunities for meeting environmental and
recreational needs during low-flow conditions in
headwater streams, especially where ranchland is
not facing development pressure. This type of ISA
could be coupled with a conservation easement on
ranchland in headwaters areas to provide for
continued irrigation in average to above average
streamflow conditions with interruption of
irrigation in below average stream conditions to
provide for in-streamflow benefits.
Rotational fallowing or ISA's could also be used
to provide for protection against the potential
for interstate compact calls.
Rotational fallowing or ISAs could also be used to
provide for protection against the potential for
interstate compact calls. Those users, generally
M~eI, who have more junior priorities and would be
among the first to be curtailed for a compact call,
could enter into an ISA or rotational fallowing
agreement with senior agricultural water rights
holders. For example, in the basins tributary to the
Colorado, there is approximately 1 million AFY of
agricultural consumptive use that would occur in a
dry year and that is senior to the Colorado River
Compact.
3.10.1 Meeting the South Metro
and El Paso County M&tl Gap with
Rotational Fallowing Program
An illustrative example was developed to show how
a rotational fallowing program could be developed
to meet the future M~eI gap in the south metro area
and El Paso County. Similar approaches could be
used for meeting the M~eI gap in f.arimer-Weld
counties. M~eI gaps in headwaters areas throughout
the state could potentially be met with a variety of
alternative transfer techniques including rotating
fallowing or ISAs. The south metro area and
unincorporated El Paso County providers have
existing non-tributary wells and a conjunctive use
arrangement could reduce the need for additional
fallowed lands during droughts. If the fallowing
program could provide average yield and negate the
need for pumping non-renewable groundwater in
most years, the existing groundwater resource could
be relied on to provide additional yield in the more
infrequent drought years.
A rotational fallowing program, as described in
Section 3.10.3, would require a large amount of
irrigated acres in the program in order to provide
50,000 to 100,000 AFY of supply for M~eI use in the
South Platte and Arkansas Basins. Using an
estimated 15 to 2.0 AF per acre of transferable CU,
an annual fallowing of 25,000 to 66,600 acres of
irrigated land would be required. If firm yield and
carryover storage were required or the agricultural
rights did not provide sufficient yield in below
average years, additional acreage would be required
to provide for carryover into drier periods.
Assuming that, on the average, 25,000 to
66,000 acres would be fallowed; a rotational
fallowing program that would result in 20 percent of
3-34 FINAL DRAFT