Water Resource Management in the Mississippi Delta

Transcription

1 Water Resource Management in the Mississippi Delta Dave Kelly Water Resource Specialist Yazoo Mississippi Delta Joint Water Management District Stoneville, Mississippi

2 Mississippi River Valley Alluvial Aquifer Alluvial Aquifer The aquifer is the source of ~95% of irrigation used in Mississippi Delta. Map credit: US Geological Survey

3 Groundwater Use Permits in the MS Delta >18,500 groundwater irrigation permits Note: Each red dot represents a permitted well > 6-inches in diameter.

4 60,000 Since 2008, irrigation permits issued for > 200,000 new acres. New Cropland Permited to Use Ground Water (Acres) 250,000 50, ,000 40, ,000 30,000 20, ,000 10,000 50, New Cumulative 0

5 Tushaar Shah (2009) Taming the Anarchy `An intensively used resource requires intensive management. 5

6 Crop Irrigation Use Estimates Overview of Methods Total water pumped by well determined using the Power Conversion Coefficient (PCC) method (Hurr and Litke, 1989) where: PCC = amount of electricity used to pump one acre-foot of water (acre-ft/kwh) Uses total kwh used during growing season to estimate total volume of water pumped: Volume water pumped = Total kwh used x PCC (acre-ft/kwh) = acre-ft Hurr and Litke (1989). Estimating pumping time and ground-water withdrawals using energy consumption data: U.S. Geological Survey Water-Resources Investigations p.

7 Crop Irrigation Use Estimates Overview of Methods Results derived using the Power Conversion Coefficient (PCC) method closely match those of Totalizing Flowmeter (Dash et al., 1999): The analysis was applied to 747 paired discharge measurements made at 105 wells during a 2-year period in Colorado. More than 80 percent of the differences were less than 10 percent. The overall mean difference was 0.0 percent, indicating no difference on average between portable flowmeter and TFM discharge measurements. Dash et al Comparison of Two Approaches for Determining Ground-Water Discharge and Pumpage in the Lower Arkansas River Basin, Colorado, U.S. GEOLOGICAL SURVEY. Water-Resources Investigations Report p.

8 Power Coefficient Conversion method for determining seasonal irrigation use Well selection criteria: Open discharge (not connected to underground piping). Well used on only one field. Dedicated electric meter. Increasingly difficult to find.

9 Power Coefficient Conversion method for determining seasonal irrigation use Flow rate (GPM) and electric power use (kw) recorded on monthly basis from April through September: April = pre-irrigation meter reading. Mid-Season = flow rate measurements. Sept = post-irrigation meter reading. Flow rate taken using ultrasonic flow meter calibrated against in-line flow meter and/or second calibrated meter. Non-intrusive approach to measurements required only temporary installation of portable flow meter.

10 Power Coefficient Conversion method for determining seasonal irrigation use Only rarely were producers aware that water use measurements were being taken. Approach leads to unbiased water use estimates (e.g., reduced potential for Hawthorne Effect). Hawthorne (Study Participation) Effect When an person s behavior is affected by the feeling of being observed or simply by the individual s participation in an experiment. Schwartz et al The Hawthorne effect and energy awareness. Proc. Nat. Acad. Sci. 110(38):

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12 Average Irrigation Use on MS Delta Crops Season year Average Crop Average Water Use per Growing Season (acre-feet) Soybean Cotton Corn Rice

13 Acre Feet Applied 2007 Crop Irrigation Use Study (N= 27 rice sites)

14 50 YMD (2009) 6-yr average water use in Mississippi rice production (A-IN/A) Contour Levees Straight Levee (SL) SL + Side Inlet Zero Grade Seasonal Rainfall 9 9

15 2012 Irrigation Energy Cost Analysis Soybean Site Irrigation Method Total Hours KPH Total Kilowatts GPM Energy Cost Cost Per Acre Cost Per Acre Foot Total AF Per Acre 1 flood , furrow ,267 1,000 6, furrow , furrow , furrow , furrow , furrow , furrow , , furrow , furrow ,

16 Uses: Future Demand Estimations

17 Source:

18 Tunica County Mississippi NASS Cropland Data Layer Irrigated Acres Superimposed Well Permit Field Boundaries Not all NASS crop area is irrigated. Source:

19 NASS Cropland Data Layer (CDL) for Bolivar County, MS 2010 Source:

20 Bolivar County Irriga on Use Es mates 2010

21 Estimated Irrigation Use in MS Delta 2010 NASS Cropland Data Layer Well Permit Field Boundaries YMD Annual Crop Water Use Survey 1 million acres not irrigated (potential future irrigation demand) 1 acre foot irrigation applied per acre

22 The entire delta calculated on 1 square mile grids.

23 Summary Crop irrigation use values are important in the management of water resources. Can be used to show trends in water and energy use and to project future irrigation demand. Crop water use is simple in concept, but good numbers require effort to obtain.

24 Questions? For information, see YMD website at