Irrigation Water Management: Opportunities and Results Presented by: Paul Stoker, Executive Director Columbia Basin Ground Water Management Area

Columbia Basin GWMA

Irrigated Acreage by Crop in the Columbia Basin Red – Low Value Green – High Value Crops CropAcresPercent Alfalfa263, % Grain**157, % All Other109, % Late Potatoes100, % Orchard*96, % Peas-Dry49,4185.3% Field Corn45,9515.0% Sweet Corn30,6333.3% 14Grass Seed***27,2752.9% Onions16,5091.8% Vineyard15,2181.6% Early Potatoes9,1591.0% Mint6,6050.7% Total928, %

Irrigation Water Management (IWM) Encourages Irrigators To:  Implement irrigation water management technologies.  Conserve water and energy. IWM Saves Water & Power Resources

“Old irrigation methods were slow, inefficient, and more often than not, guess work. IWM real-time technology reduces our water and energy costs, and increases our crop quality and yield.” ---Wes Boorman, Boorman Farms, George, WA.

Example of Evapo-Transporation (ET) Based Irrigation Scheduling 1993 Growing Season, Grant County Irrigation Project Evaluation, J.D. Miller, March 1994, Pacific N.W. Laboratory POTATO (Late Russet) Acres KwH/Acre Inches/AcreYield Ton/Acre Non-Participant Participant Total IWM Savings 15%

IWM Soil Moisture Graph

Nitrate Movement in Soil Native Soil Native Soil shows consistent low levels of nitrate.

Nitrate Movement in Soil Continuous High Leaching Excessive irrigation leaches nitrate into the soil profile.

Nitrate Movement in Soil Maximum Management Potential Proper irrigation water management saves water and keeps fertilizer in root zone.

“I believe in the time it takes to do moisture monitoring. IWM has given me a better understanding of my farming practices.” -- Bob Ransom, Benson & Ransom Farms Pasco, WA

IWM 10-Point Plan Criteria 1. Measure and document the PCC value for each irrigation system. irrigation system. 2. Determine amount of water delivered to an area.  Know the application rate. 3. Determine when irrigation water should be applied, based on:  crop usage rate,  stage of plant growth,  cooling,  frost control or  salt leaching.

IWM 10-Point Plan Criteria 4 4. Be aware of average time needed for soil to absorb required amount of water. 5. Know application rate, irrigation time, rotation time, or stream size to compensate for changes in such factors as intake rate or the amount of water to be applied. 6. Understand distribution uniformity and application efficiency concepts and their implications on IWM:  Have an in-field uniformity evaluation.  Have an Operations and Maintenance Plan.

IWM 10-Point Plan Criteria 7. Know how to recognize water (and nitrogen) movement past the crop rooting zone. 8. Maintain records of irrigation applications. 9. Have a soil moisture monitoring system in place and maintain records.

IWM 10-Point Plan Criteria 10. Average measured irrigation application total (seasonal) should not exceed crop (seasonal) should not exceed crop consumptive use by more than 10% … as consumptive use by more than 10% … as determined by use of : determined by use of :  Agrimet,  PAWS,  Personal weather station evapo- transporation (ET) data,  Crop water use coefficient curves.

Why the 10-Point Plan is Successful  Contract signed pre-season – payment only upon completion.  Site specific to each field.  Program implementation oversight.  Credibility with agricultural community  Required documentation forces grower to actively participate  50% cost share by growers buys grower involvement. Why the 10-Point Plan is Successful

 Reimbursement based on actual cost encourages competition among providers  Simple, realistic and easily understandable by growers and consultants  Covers all important aspects of IWM – not just SIS.  Requires growers to sign-up and commit individually in person.

 Monetary incentives can provide significant conservation investment returns.  Variable rate cost-share program specifies savings by crop and location.  Incentive payments are based on potential savings.  IWM saves power and water at the field.  Water not diverted from Lake Roosevelt for irrigation has high value. Columbia Basin IWM Benefits

Conservation Benefits Spreadsheet  Spreadsheet calculates the potential water and power savings by using Irrigation Water Management in the Columbia Basin.  Four main variables can be entered to customize the spreadsheet to a given scenario.  Spreadsheet creates a variable cost-share value based on different crops and locations.  Summary on the spreadsheet can demonstrate total conservation benefits available. (See Spreadsheet)