Conservation of surface and ground water in a Western watershed experiencing rapid loss of irrigated agricultural land to development

Transcription

1 Conservation of surface and ground water in a Western watershed experiencing rapid loss of irrigated agricultural land to development Dr. Rob Van Kirk, Humboldt State University, Project Director Brian Apple, Humboldt State University Dr. J. Mark Baker, Humboldt State University Dr. Yvonne Everett, Humboldt State University Dr. Brad Finney, Humboldt State University Lora Liegel, Humboldt State University Kimberly Peterson, Humboldt State University Dr. Steve Steinberg, Humboldt State University Dale Swenson, Fremont-Madison Irrigation District Steve Trafton, Henry s Fork Foundation Amy Verbeten, Friends of the Teton River Funded by U.S. Department of Agriculture

2 Outline Project objectives Accomplishments since March 2009 Results to date Plans for the next year Food for thought and future discussion (if time) Water conservation Efficiency of water use Economic sustainability

3 Project Objectives 1. Model ground and surface water flow under historic, current and future land and water use scenarios 2. Identify socioeconomic factors that determine water use on formerly irrigated land that has been developed and on irrigated land in proximity to development 3. Provide information on hydrology and water use to decisionmakers and stakeholders 4. Develop strategies to increase water availability for agriculture while enhancing ecological benefits in key stream reaches 5. Train an interdisciplinary team of graduate students

4 Accomplishments since March 2009 Met with numerous stakeholders in the watershed Created project web site Submitted annual report to USDA Presented preliminary results at National Water Conference Compiled GIS data on land use changes Investigated water rights associated with developed land Measured canal and stream channel loss/gain rates in the field Modeled flow in Teton and Trail creeks Developed method for calculating irrigation water budget

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6 Platted Subdivisions IDWR Irrigation Water Rights by Place of Use IDWR Recommended Water Rights by Place of Use Coordinate System: NAD83_State_Plane_Idaho_East_FIPS_1101_Feet Data Sources: Fremont, Madison and Teton Counties; Idaho Tax Commission, IDWR, Dr. Rob Van Kirk Miles Produced by, Lora Liegel, 3/9/10 Red shows all platted subdivisions and townsites Green and yellow indicate lands with irrigation water rights

7 Only subdivisions located on land with irrigation water rights are shown here. Subdivisions on Potentially Irrigable Lands IDWR Irrigation Water Rights by Place of Use IDWR Recommended Water Rights by Place of Use Coordinate System: NAD83_State_Plane_Idaho_East_FIPS_1101_Feet Data Sources: Fremont, Madison and Teton Counties; Idaho Tax Commission, IDWR, Dr. Rob Van Kirk Miles Produced by, Lora Liegel, 3/9/10

8 Cumulative area (acres) 30,000 25,000 20,000 Fremont County Madison County Teton County 15,000 10,000 5, Year Cumulative area of subdivisions platted since 1970, excluding Island Park. Total irrigated land area in watershed is about 275,000 acres.

9 What happens to surface water rights when land is sold for development? 1. Landowner/water user retains water rights 2. Water rights sold to other irrigator(s) in same canal company 3. Water rights sold to developer 4. Other What happens to the water itself? In cases 1 or 2 above, water continues to be diverted and used for irrigation on adjoining land. New landscaping is watered with ground water (individual or community well). In case 3, water is applied to landscaping/waterscaping or continued agricultural production on same land. New homes use ground water for domestic use only. Other

10 Modeling Flow in Trail and Teton Creeks Two largest tributaries in Teton Valley Critical for modeling hydrology of upper Teton River USGS gages recorded flow data for water years Since then, measurements made only periodically during irrigation season Modeling approach: Develop statistical relationship between Trail and Teton creeks and a similar stream with long continuous period of record.

11 A good reference stream: Pacific Creek, Wyoming Teton Creek Pacific Creek TrailCreek

12 Discharge (cfs) Trail Creek Model Validation Observed Predicted 10/1/ /1/ /1/ /1/ /1/ /1/1951 Daily flow Monthly flow Bias -0.12% -0.58% Mean absolute error 9.1% 6.8% Modeling efficiency 94.2% 97.5%

13 Discharge (cfs) Discharge (cfs) Predicted Teton Creek Flow Oct-78 Oct-80 Oct-82 Oct-84 Oct-86 Oct-88 Oct-90 Oct Oct-93 Oct-95 Oct-97 Oct-99 Oct-01 Oct-03 Oct-05 Oct-07 Full series is WY and WY

14 Measuring loss in canals a difficult task!

15 Depth (ft) Canal and Stream Channel Gain/Loss Estimation Width (ft) Measure discharge at top and bottom of reach Measure wetted perimeter (e.g., 26.4 feet for this canal) Measure length of reach from map Total wetted area = length average wetted perimeter Gain or loss rate = (Q bottom Q top )/wetted area Loss expressed in ft 3 /day/ft 2 (or ft/day)

16 Canal and Stream Channel Loss Statistics Based on all usable observations made last summer, made in a pilot study in 2005, and obtained from IDWR records n Mean loss (ft/day) 95% Confidence interval Canals in Ashton/St. Anthony/Rexburg area (1.73,3.59) Streams on Teton Range alluvial fans (2.83,3.97) Canals on Teton Range alluvial fans (2.38,4.94) University of Idaho estimates for Rigby Fan, made in 1970s Range: Mean used in ground-water model: 2.5

17 Depth (ft) Canal Loss Model 1. Calculate wetted perimeter and water surface area from geometry and flow 2. Wetted area = length wetted perimeter. 3. Total loss = loss rate wetted area. Recharge to aquifer = TOTAL EVAP RIPARIAN ET Evaporation = Open-water ET Surface area Width (ft) Loss to vegetation = ET riparian width

18 Measuring canal parameters from satellite images

19 Result of model applied to a large canal system Ground-water Recharge 31.9% Canal & Riparian ET 0.3% Applied to Crops 54.0% Surface Return Flow 13.8%

20 Plans for the next 12 months Conduct formal stakeholder interviews to investigate factors affecting water use and management on/near developed lands Validate/calibrate measurements made from maps/images Watershed Council field trip July 20 Finish hydrologic modeling Present results at National Water Conference and other meetings/conferences Begin developing water management strategies and discussing them in Watershed Council

21 Things to think about What is water conservation? What is efficient water management? DISCLAIMER The following example management actions are hypothetical, not ones that are necessarily feasible or even possible under current water law. We are NOT recommending ANY management actions now nor judging the value of these examples.

22 Example 1. Increase irrigation efficiency by lining canals and/or delivering water in pipelines to reduce seepage. Example 2. Reduce water consumption by using xeriscaping in new residential developments, and retire irrigation systems that currently serve these lands. Savings from these measures could benefit: Instream flow/fish and wildlife (especially those dependent on flashy, snowmelt hydrologic regimes) Increased agricultural production (junior users would have greater supply in dry years) Increased hydroelectric production

23 Example 3. Increase ground-water recharge by returning to subirrigation, flood irrigation and other direct application methods. Example 4. Increase ground-water recharge by encouraging new developments to incorporate unlined channels and ponds as part of landscaping. Increased aquifer storage could benefit: Spring and wetland habitat and associated species Ground-water irrigators Municipal/domestic supplies Aquaculture Which conservation measures are appropriate depends on location, hydrogeology, and resources being considered.

24 Things to think about Sustainability of agriculture and economy in upper Snake River Basin DISCLAIMER These are my (RVK s) observations and DO NOT necessarily reflect those of my colleagues and collaborators. These ideas are NOT direct results of the current project but grew out of presentations and discussions at the 2010 National Land Grant and Sea Grant Water Conference.

25 (Replaced Cooperative State Research, Education and Extension Service) Goals of current research program 1. Keep American agriculture competitive while ending world hunger 2. Improve nutrition and end child obesity 3. Improve food safety for all Americans 4. Secure America s energy future through renewable biofuel 5. Mitigate and adapt agriculture to variations in climate Specific areas of emphasis include Sustainable agriculture Rural and community development

26 Why the upper Snake River Basin can play a major role in the future of U.S. food and energy supplies Produces staple food items in quantities of regional and national significance Potatoes Grain Dairy Culinary trout Can complement food production with renewable energy production Biofuels Wind Solar Hydroelectric

27 Why irrigated agriculture in the upper Snake River Basin can be sustainable and resilient to climate variability Large water supply in snowpack that is least susceptible to effects of warming Well-drained soils (little to no salt accumulation problem) Reservoir storage capacity appropriate in volume to supply and demand Large ground-water storage capacity in Henry s Fork headwaters buffers variability in snowpack Large ground-water storage in Eastern Snake Plain Aquifer and smaller local aquifers offers further buffering Inexpensive, energy-efficient, low-tech water delivery system (gravity) Canal system moves water from surface sources to ground-water supply Effective water management, accounting and planning structures involving mix of private, public, local, state and federal entities

28 Why the economies of rural communities in the upper Snake Basin can be sustainable and resilient Sustainable agriculture is the foundation Agriculture is complemented by and compatible with other sectors: Outdoor-related recreation and tourism Research and education (INL, BYUI) Renewable energy Geography and natural resources that are unique in the U.S. Yellowstone, the Tetons and the Snake River cannot be produced overseas Challenges ahead? Conjunctive management and CAMP implementation Balancing urban/suburban economic growth with agricultural production Continued adaptive management and research to sustain important fisheries without jeopardizing agricultural water supply And many others..

29 My personal goal To provide objective information derived from peer-reviewed research that can help meet these challenges.