COST ANALYSIS OF WATER MANAGEMENT ALTERNATIVES FOR THE MISSISSIPPI DELTA

Transcription

1 COST ANALYSIS OF WATER MANAGEMENT ALTERNATIVES FOR THE MISSISSIPPI DELTA 2017 Mississippi Water Resources Conference Jackson, MS April 11, 2017 Presented by Larry Falconer Extension Economist

2 OBJECTIVE The objective of this study is to provide MDEQ with a report comparing the cost of reduced pumping or increase in recharge per acre foot in the Mississippi River Valley Alluvial Aquifer as a result of 5 proposed groundwater management alternatives with scenarios. Delta Research and Extension Center (DREC) personnel involved in this study are Dr. Lawrence Falconer, Dr. Rachna Tewari (University of Tennessee, Martin) and Dr. Jeff Johnson.

3 METHODOLOGY The USGS and MDEQ collaborated with MSU-DREC, USDA-NRCS, USDA- ARS, YMD and USACE to develop scenarios listed below that were modeled by USGS: Implementation of water use efficiency practices (MSU-DREC) Tail-water recovery systems and on-farm water storage systems (USDA-NRCS) Groundwater-to-groundwater transfer project (USDA-ARS) Tallahatchie River-Quiver River intra-basin surface water transfer (YMD & USACE) In stream weirs to provide additional surface water (USACE)

4 METHODOLOGY (continued) After the alternatives were defined, each organization provided initial construction, operating and maintenance cost estimates for implementation of the scenarios. Cost estimates were adjusted for future input price changes utilizing appropriate inflation rates and normalized using capital budgeting techniques consistent with the planning horizon utilized in the USGS modeling. The discount rate used for net present value calculations in this study is the federal interest rate for USACE projects for fiscal year The heights for water lift for the Delta and the Central Delta regions were assumed to be at 75 feet and 120 feet respectively. Irrigation well operating and maintenance costs were estimated to be $1.23/ac-in Delta-wide and $1.90/ac-in for the central Delta. No financial assistance or cost distribution between entities is included in this stage of analysis.

5 RISER Delta Wide RISER Central Delta RISER Acres in Project 1,453,074 91,590 Estimated Total NPV Cost of Project $354,913, $9,295, Annual Reduction in Pumping (acre ft) 530,647 36,710 Total Reduction in Pumping (acre ft) 26,532,350 1,835,500 Cost of Change per Acre Foot $13.38 $5.06

6 TAIL WATER RECOVERY (TWR) AND ONFARM STORAGE (OFS) Delta Wide TWR +OFS Delta Wide TWR Delta Wide 50% OFS+TWR/50% TWR mix Acres in Project 40,000 40,000 40,000 Annual Reduction in Pumping(acre ft) Estimated Total NPV Cost of Project Total Reduction in Pumping (acre ft) Cost per acre foot ($/acre ft) 55,297 18,432 36,865 $54,628,500 $22,238,960 $38,433,730 2,764, ,600 1,843,250 $19.76 $24.13 $20.85

7 Enhanced Aquifer Recharge NPV of Total Cost Annual Change in Aquifer (acre ft) Total Change in Aquifer (acre ft) Average Cost Change in Aquifer ($/acre ft) Enhanced Aquifer Recharge Scenario $263,810, ,976 6,048,800 $43.61

8 Tallahatchie-Quiver Intra-basin Transfer NPV of Total Cost Reduction in Pumping Annual (acre ft) Total (acre ft) Average Cost of Change ($/acre ft) Tallahatchie/ Quiver 1/2 mile area 100% $40,369,190 36,289 1,814,450 $22.25 Tallahatchie/ Quiver 1/2 mile area 66% $42,559,883 23,951 1,197,550 $35.54 Tallahatchie/ Quiver 1/2 mile area 33% $44,680,714 11, ,750 $74.62 Tallahatchie/ Quiver 1 mile area 100% $53,868,434 71,917 3,595,850 $14.98 Tallahatchie/ Quiver 1 mile area 66% $51,427,291 47,465 2,373,250 $21.67 Tallahatchie/ Quiver 1 mile area 33% $49,113,657 23,733 1,186,650 $41.39

9 In Stream Weirs for Surface Water NPV of Total Cost Reduction in Pumping Annual (acre ft) Total (acre ft) Average Cost of Change ($/acre ft) In Stream Weirs 1/2 mile area 100% $1,811,916 73,290 3,664,550 $0.49 In Stream Weirs 1/2 mile area 66% $6,724,753 48,792 2,436,600 $2.76 In Stream Weirs 1/2 mile area 33% $11,560,932 24,186 1,209,300 $9.56 In Stream Weirs 3/4 mile area 100% $8,854, ,859 5,442,950 $1.63 In Stream Weirs 3/4 mile area 66% $11,397,970 71,847 3,592,350 $3.17 In Stream Weirs 3/4 mile area 33% $13,897,922 35,923 1,796,150 $7.74

10 COST COMPARISON OF WATER MANAGEMENT ALTERNATIVES FOR THE MISSISSIPPI DELTA Water Management Scenario Reduction in Pumping (acre ft/ year) Cost ($/acre ft) RISER Delta wide RISER Central Delta 530,647 36, TWR 18, TWR + OFS 55, % TWR+OFS/50% TWR 36, Enhanced Aquifer Recharge 120, Tallahatchie/Quiver Intra basin 100% adoption ½ mile area 36, % adoption ½ mile area 11, % adoption 1 mile area 71, % adoption 1 mile area 23, In Stream Weirs (Surface water) 100% adoption ½ mile area 73, % adoption ½ mile area 24, % adoption ¾ mile area 108, % adoption ¾ mile area 35,

11 CONCLUSION Results suggest that the in stream weirs program resulted in the lowest costs of implementation measured as cost in dollar per-acre foot of reduced pumping from the aquifer. This study provides an initial estimate of the costs associated with the different water management alternatives, and builds the groundwork for future in-depth studies addressing the feasibility of implementation, and the associated costbenefit trade-offs for the proposed water management strategies in the Mississippi Delta.

12 ACKNOWLEDGEMENTS Dr. Jeannie Barlow, USGS Mr. Sam Mabry, MDEQ Dr. Jason Krutz, MSU Mr. Paul Rodrigue, USDA-NRCS Dr. J. R. Rigby, USDA-ARS Mr. Mark Stiles, YMD Mr. Dave Johnson, USACE

13 Questions?