Final Draft ALP Marketing Supply and Demand Study

A -LP Water Animas -La Plata Water Marketing Supply and Demand Study Section 3
A CWCB- sponsored report, "Climate Change in Colorado - A Synthesis to Support Water Resources
Management and Adaptation" (CWCB and CU -NOAA Western Water Assessment, 2008) provides a
comprehensive review of greenhouse gas emission scenarios, global climate models, and resulting
climate projections. This Report indicates that on average temperatures in Colorado are likely to rise 4
degrees Fahrenheit (deg F) by 2050. High variability in precipitation makes detection of precipitation
trends difficult. Regardless of precipitation, increased temperatures could result in implications for water
resource managers.
In a more recent effort, The Colorado River Water Availability Study ( CRWAS), superimposed the effects
of potential changes in precipitation and temperature from previously developed global climate models
(also known as General Circulation Models) to reflect hydrologic conditions that may exist in 2040 and
2070 in the portions of the Colorado River Basin within Colorado. Only demands that were irrigation
based were revised to reflect climate projections.
Under climate change projections, basin -wide temperatures increase by 3.3 to 3.7 degrees Fahrenheit
(deg F) by 2040, with lower elevations showing the largest increase. Temperature increases occur each
month of the year. Increased temperatures could result in changes in evapotranspiration (ET), the most
significant water loss process in the hydrologic water balance.
Results from the first phase of the CRWAS study also show that annual modeled streamflow decreases
basin -wide, except in the Yampa River basin, and higher elevation locations in the Upper Colorado River
basin. Reservoirs throughout the basin show increased use, meaning that pool levels fluctuate more
than they have historically. Reservoir operation regimes could play an important role in meeting water
demands under future climate conditions and variability.
Given the increased variability in precipitation for Archuleta and La Plata counties, access to supply
water from an already constructed reservoir will be an important for meeting supplies in times of water
shortage and to continue to meet environmental compliance requirements.
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FINAL ALP Repert_1_13_11_LL.dccx