Natural Resources of the West: Water and Drought

Transcription

1 Prowers Co., Colorado, (Western History Collection, University of Oklahoma) Natural Resources of the West: Water and Drought What is Drought? Thirsty corn in Iowa Drought in India Gigi A. Richard Associate Professor of Geology Colorado Mesa University Grand Junction, CO

2 What is Drought? Definitions of drought Overview of water in Colorado Major rivers Colorado Water Law Colorado River Compact Typical hydrologic regime of Colorado s Rivers Drought history in western US Recent drought years and 2012 drought

3 What is drought? Drought When there is not enough water? How much is enough? Bali? Grand Junction? Impacts vary from region to region A dust storm approaching Rolla, Kansas, May 6, (Image: Franklin D. Roosevelt Library Digital Archives)

4 Drought What is drought? an extended period of dry weather, especially one injurious to crops (Random House Dictionary) period of extended dry weather that is abnormal for a region (from US National Weather Service) A farmstead and farm equipment buried in dust during the mid-1930s. (Image: NOAA/Department of Commerce)

5 What is drought? Drought originates from a deficiency of precipitation over an extended period of time--usually a season or more--resulting in a water shortage for some activity, group, or environmental sector (National Drought Mitigation Center,

6 Drought Aridity Aridity is a permanent climatic condition in a region, whereas drought is a temporary lack of moisture

7 (Source: National Drought Mitigation Center, University of Nebraska-Lincoln, U.S.A.)

8 Four stages of drought 1.Meteorological Drought departure from normal precipitation 2.Hydrological Drought below-normal surface and groundwater supplies 3.Agricultural Drought Inadequate water supplies to grow a particular crop 4.Socioeconomic Drought Inadequate water supplies to serve local residents

9 What is drought? Drought How do we determine when lack of precipitation = drought? Difficult to determine! Science-based assessments

10 What is drought? Drought Impacts result from the interplay between the natural event (less precipitation than expected) and the demand people place on water supply, and human activities can exacerbate the impacts of drought (National Drought Mitigation Center,

11 Image credit: Colo. Foundation for Water Education Major Rivers of Colorado

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13 Trans-mountain diversions Alva B. Adams Tunnel, which diverts water from Lake Granby through the Colorado-Big Thompson Project

14 Basin area 637,000 km 2 Length 2,900 km Mean annual discharge m 3 /s 22,000 cfs m 3 /s < 4,000 cfs

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16 84% of watershed receives < 51 cm/yr 34% of watershed receives <25 cm/yr Most of the runoff is produced by only 15% of the drainage area

17 Fassnacht 2006

18 Storage and Diversions st dam in basin - Theodore Roosevelt dam on the Salt River 1.9 x 10 9 m 3 Total storage capacity is now 114 x 10 9 m 3 (92.8 x 10 6 ac-ft) 7 times the long-term mean annual flow at Lees Ferry (Schmidt 2007) 18 major dams with storage capacity >1.0 x 10 9 m 3 Hoover Dam, 1935 Lake Mead 37x10 9 m 3 storage capacity Photo by Peter McBridge Glen Canyon Dam, 1963 Lake Mead 35.5 x 10 9 m 3 storage capacity Photo by Peter McBridge

19 All-American Canal allows irrigation of more than 2,000 km 2 in California carries 740 m 3 /s (26,000 cfs) largest irrigation canal in the world Consumptive use has Colorado River Aquaduct Los Angeles & the long-term Photo from Nasa.gov San average Diego Storage and Diversions increased to about 90% of annual flow at Yuma (Schmidt 2007) The Central Arizona Project canal pumps Colorado River water out of Lake Havasu and 336 miles east and uphill to supply Phoenix, Tucson, and 12 sets of aquifer recharge ponds. Photo by Peter McBridge

20 The most regulated river in the world

21 Colorado River Compact Divides basin into Upper and Lower Basins water between 7 US states, Mexico and native american tribes 1922 compact based on 2 of the wettest decades in the last 500 years.

22 Interstate & International Compacts From Citizen s Guide to Colorado Water Law, 2003, prepared by Colorado Foundation for Water Education

23 Colorado Water Law In a dry and thirsty land it is necessary to divert the waters of the streams from their natural channels Colorado water law is based on the force of necessity arising from local peculiarities of climate Colorado Territory, Supreme Court Justice Moses Hallett, 1861 From Citizen s Guide to Colorado Water Law, 2003, prepared by Colorado Foundation for Water Education

24 Colorado Water Law Colorado water law water can be diverted from the stream, and ditches built across public and private land to convey water to its place of beneficial use Contrast with Riparian Doctrine From Citizen s Guide to Colorado Water Law, 2003, prepared by Colorado Foundation for Water Education

25 Prior Appropriation System Legal framework that regulates the use of surface water in rivers or ground water connected to rivers Mandated by Colorado s constitution Also called priority doctrine From Citizen s Guide to Colorado Water Law, 2003, prepared by Colorado Foundation for Water Education

26 Beneficial Use lawful appropriation that employs reasonably efficient practices to put that water to use without waste Recognized beneficial uses CWCB instream flows (1973) Commercial Domestic Dust suppression Fire protection Fish and wildlife culture Flood control In-channel recreational diversions for rafting & kayaking (2001) Industrial Irrigation Mined land reclamation Municipal Nature centers Power generation Recreation Release from storage for boating & fishing flows Snowmaking Stock watering From Citizen s Guide to Colorado Water Law, 2003, prepared by Colorado Foundation for Water Education

27 Beneficial use (con d) Right to use the water without owning the water! Water is owned by the public use it or lose it only can divert what you NEED! Diverting more than is needed is water waste. Define NEED amount needed to move water to the place where it will be used Amount needed for beneficial consumptive use Agricultural water use can be 20-75% consumptive depending on soil type, crop planted, geographic location, or irrigation method. Municipal varies from 5% in winter to 50% in summer during summer landscape irrigation From Citizen s Guide to Colorado Water Law, 2003, prepared by Colorado Foundation for Water Education

28 Drought and the Colorado River

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30 1982 m 3 /s

31 Annual Hydrographs at CO-UT state line

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35 2012 Drought Update!

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38 2012 Update July monsoonal rains beneficial moisture to most of the west slope, dropping as much as 300% of average precipitation over parts of the central mountains and foothills; and relieving, but not eliminating, drought conditions. Above average temperatures throughout the summer. warmest June on record, July continued fifth warmest on record. January July 2012 second warmest calendar year since 1895 when records began. August so far has been slightly cooler

39 2012 Update Colorado Drought Mitigation and Response Plan (DMRP) Revised in 2010 monitoring, assessment, mitigation, and response Aug 10 th - Governor Hickenlooper elevated activation for agricultural sector to Phase 3

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41 2012 Update Reservoir storage is at 73% statewide. Highest storage levels - Yampa/ White River Basin, 112% of average largely dominated by energy producers who are keeping their water in storage in case the drought persist, roughly 2/3 of storage in the major reservoirs of that basin is held by energy producers. lowest storage in the state is in the Rio Grande River basin at 52% of average. Otero, Bend, Prowers, Crowley and Kiowa Counties experienced extreme drought conditions last summer had not fully recovered, exacerbating conditions and impacts this year. Failed and prevented crop planting figures have increased since early July and irrigation abandonments are now being reported as well.

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