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8/12/2014
1
A Novel Test of Artificial Recharge in
the Mississippi River Alluvial
Aquifer in Arkansas
Michele L. Reba, PhD...
8/12/2014
2
• Recharge rate
• Cost (installation, equipment, energy,
maintenance)
• Long-term performance
• Water-quality ...
8/12/2014
3
Recharge Test (Phase 1)
• Pump from well 1
• Inject in well 2 (about ½ mile from pumped
well)
• Monitor water ...
8/12/2014
4
44
45
46
47
48
49
50
51
52
53
54
1/17 1/18 1/18 1/19 1/19 1/20 1/20 1/21 1/21
Date
Waterlevelabovetransducerin...
8/12/2014
5
Preliminary Results
• Statistically significant difference in means
p-value < 0.01
– Phosphates,Turbidity, TS
...
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A novel test of artificial recharge in the mississippi

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69th SWCS International Annual Conference
“Making Waves in Conservation: Our Life on Land and Its Impact on Water”
July 27-30, 2014
Lombard, IL

Published in: Environment
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A novel test of artificial recharge in the mississippi

  1. 1. 8/12/2014 1 A Novel Test of Artificial Recharge in the Mississippi River Alluvial Aquifer in Arkansas Michele L. Reba, PhD, PE USDA-ARS Delta Water Management Research Unit USDA Preserving water quality & availability for agriculture in the Mississippi River Basin Delta Water Management Research Unit • Jonesboro, AR • Arkansas State University • 2011-Watershed Physical Processes Unit • 2014-stand alone unit Arkansas 4.5 million Nebraska 8.4 million California 7.3 million Texas 5.4 million Water Quantity Arkansas 6.1 M acres farmed 4.5 M acres irrigated Alluvial Aquifer • 2008 (Mgal/d) – Pumped: 7,022 – Sustainable Yield: 2,987 – Unmet Demand: 4,035 • Agriculture 96% Source: Arkansas Natural Resources Commission 2011 Approaches Toward Sustainability • Conservation • Surface-water diversions • Technology • On-farm storage • Artificial recharge Potential Storage in Alluvial Aquifer • Water removed from storage since pumping began: 1.5 trillion cubic ft (or 35 million acre ft) • Equivalent water depth if applied over area of aquifer: 4 ft • Years to refill this volume at a rate of 1,000 gallons per minute: 21,000 years • Depletion is continuing
  2. 2. 8/12/2014 2 • Recharge rate • Cost (installation, equipment, energy, maintenance) • Long-term performance • Water-quality of recharge water • Water-quality changes in aquifer • Flow of recharged water within aquifer Artificial Recharge Viability Issues Artificial Recharge in Arkansas • 1960’s: USGS conducts artificial recharge study at Rice Experimental Station • USGS concludes that recharge could be done at a finite percentage of pumping rate • Major factors affecting recharge: – air entrainment – sediment clogging – chemistry • Major deterrent: cost of water treatment Background • Bryan Huber – Where idea originated – Benefits to be derived – Potential sources of recharge water – Earlier attempt at recharging aquifer • Cotton Inc. Core Funding – Groundwater/surface water interaction – Viability of surface water storage Objectives • Field test of viability of alluvial aquifer recharge with groundwater • Quantify water quality of potential recharge sources • Quantify efficacy of low-cost filtration techniques Study Site • Poinsett County • Largest rice producing • Groundwater decline Description of Recharge Test • Monitor water levels from 4 observation wells prior to, during, and after recharge • Pump water from one well and recharge it in another well ½ mile away • Monitor pumping rate
  3. 3. 8/12/2014 3 Recharge Test (Phase 1) • Pump from well 1 • Inject in well 2 (about ½ mile from pumped well) • Monitor water levels before, during, and after water injection • Monitor flow rate, turbidity, and water temperature Pumping well Recharge well Flow meter Turbidity sensor Riser pipe Test results • Average recharge rate: 565 gallons per minute • Water level rise after 3.8 days: 38 ft (well 2); 0.7 ft (well 2A) • Head space remaining in recharge well: ~80 ft 47 57 67 77 87 97 1/13 1/14 1/15 1/16 1/17 1/18 1/19 1/20 1/21 Date Waterlevelabovetransducerinwell2,feet 44 44.5 45 45.5 46 46.5 47 Waterlevelabovetransducerinwell2A,feet Water level in well 2 Water level in well 2A
  4. 4. 8/12/2014 4 44 45 46 47 48 49 50 51 52 53 54 1/17 1/18 1/18 1/19 1/19 1/20 1/20 1/21 1/21 Date Waterlevelabovetransducerinwell2,feet Water level in well 2 Water level in well 2A Slope of recovery curve in Well 2 Well 2 Well 2A Well 2A Residual Water-Level Buildup Well 2 Residual Water-Level Buildup 0 1 2 3 4 5 6 7 8 1 10 100 1000 10000 Time since recharge stopped, minutes Residualwater-levelrise,feet S= (2.5- 1.2) ft = 1.3 ft T = 264 Q/S = 264 x 565 gpm/1.3 ft = 114,700 gpd/ft = 15,340 ft2/day Test Summary • Recharge well accepted water readily at average rate of 565 gallons per minute • Maximum water level rise was 38 feet • Water level rise at 330 feet was 0.7 ft after 3.8 days of injection • Transmissivity estimate was comparable to values from tests in other wells • Air entrainment not a large impediment to recharge • Recharge rate could be increased substantially Water Quality • Expense of water treatment • Wetlands • Filtration • Reservoir construction – 2000-2009: 111 – 2012: 30 – 2013: 54 Study Site • 5 Ditch/Reservoirs • Henry/Hilleman Silt loam • Nutrients • Sediment 70 ac 1980s 140 ac 1980s 40 ac 2000s 40 ac 2000s 70 ac 2010s
  5. 5. 8/12/2014 5 Preliminary Results • Statistically significant difference in means p-value < 0.01 – Phosphates,Turbidity, TS • Median % Reductions: 15%-70% • Generalizations – Size of ditch – Seasonality 0.000 0.100 0.200 0.300 0.400 0.500 0.600 EDCBA TotalSolids(g/L) Site Reservoir Ditch Filtration Test Continued Effort • Filtration testing • Continued water quality sampling – Sediment – Nutrients – Metals • Inventory of reservoirs Acknowledgments • Bryan Huber • Cotton Inc. • John Czarnecki (University of Arkansas- Little Rock) • J.R. Rigby (USDA-ARS) • Jerry Farris (Arkansas State University) • Cart Well, Inc. • Depth to water: ~120 ft. • Average unsaturated thickness: ~70 ft. • Assumed specific yield: 0.20 • Storage per acre: 14 acre-ft • Area of Huber farm: 1400 acres • Aquifer storage: 19,600 acre-ft • Time needed to fill at 500 gpm: 24 years! Aquifer Storage Potential

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