1 Sustainability on the Border: Water, Climate, and Social Change in a Fragile Landscape The University of Texas at El Paso Economics of Water Supply, Demand, and Conservation in the Paso del Norte Region Frank A. Ward NM State University May 18, :30 – 12:50 pm

2 Road Map Pose questions –What is water conservation in agriculture? –What policies could promote it? –Can river basin policy models help discover these policies? –Findings about effects of water conservation incentives in the Paso Del Norte Region

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4 Rio Grande Basin

Journey down the Rio Grande 5 Snow melt: 1 a-f Rio Grande Silvery Minnow CBP pumped water Elephant Butte, Caballo SLV Irrigation EBID Irrigation Sangre De Cristo Headwaters El Paso urban (sw +gw) Heron, El Vado, Abiquiu, Cochiti West TX Irrigation Albuquerque urban (sw + gw) Mexico Ag MRGCD Irrigation Mexico Urban

6 High Valued Uses of Water in RGB, Albuquerque, El Paso

High Valued Use: Rio Grande Silvery Minnow 7

High Uses of Water in RGB, Irrigation 8

9 Approach

Water Pricing and Cost Recovery Timing, sizing, sequencing of new storage Population growth, increased food demands, ‘more crop per drop.’ Water rights adjudication Meeting growing demands for environment How to develop/allocate water for food security Cheapest way to reduce water use (conservation) 10 Policy Debates Basin Models Can Inform

Maximize –Objective Economic Environmental Social Justice Hydrologic Subject to –Constraints Hydrologic Agronomic Institutional Economic 11 Basin Model (Optimization)

Policy Assessment Framework 12 Data Headwater supplies Min Flows Sharing rules Outflows Crop prices Crop costs Water price Treat cost Elasticities Land supply Process Maximize NPV for the basin Outcomes Crop prodn Crop ET Urban water diversions, use, Return flows, Flows by gauge Urban, farm, environmental benefits NPV Baseline: no new policy Alt 1: Constrain aquifers to return to start Alt 2: Renew aquifers to historical levels Policy

Connections Connections: River basin models –Hydrologic: stocks, flows, over time, space –Economic: optimizes total benefits from use –Agronomic: acreage, water use, crops –Demographic:urban income, population, demand –Institutional: rules that limit use or require delivery Gain insights into policies that best adapt to climate: resilient conservation institutions –For basin as a whole (or part, e.g. Paso del Norte Region ) –For targeted users (farm, city, environment) 13

14 Water Balance

15 Crop Water Use Data, RG Basin, NM CropTech AETDP Yield tons/ac Tech AETDP Yield tons/ac ac-ft/ac/yr Alfalfaf d Cottonf d Lettucef d Onionsf d Sorghumf d Wheatf d Green Chilef d Red Chilef d Pecansf d

NM Pecans: Water Balance 16 Drip 6’ 2.6’ 3.4’ Flood 3.2’ 0 0

17 A Peek at the Model

18 Objective

Irrigable land, Headwater supplies Sustain key ecological assets Hydrologic balance Reservoir starting levels (sw, gw) Reservoir sustainability constraints (sw, gw) Institutional –Endangered Species Act –Rio Grande Compact (CO-NM; NM-TX) –US Mexico Treaty of 1906 –Rio Grande Project water sharing history (NM/TX) 19 Constraints

E.g.: Lobatos gauge (CO-NM border): X(Lobatos_v,1) = X(RG_h,1) - X(SLV_d,1) + X(SLV_r,1) 20 Gauged Flows: Hydro Balance

21 Ag water use

Ag Water Use and Savings –Water Supply (normal, dry, drought) –Ag water Conservation Subsidies (low to high) 22 Results of Ag Water Conservation Policy Analysis

23 Water Use by Technology and Policy LRGB (AF/yr, ET) TechUnits Base Alternative 1: Sustaining Natural Capital Alternative 2: Renewing Natural Capital use changeusechange Flood absolute 146,26694,917-51,34994,375-51,891 pct Drip absolute 52,6044,402-48, ,602 pct Total absolute 198,86999,318-99,55194, ,493 pct

24 Economic Value of Water by Water Shortage and Drip Irrigation Subsidy, Rio Grande Project, USA, $ / Acre Foot for Water Depleted Water Supply Scenario % Capital Subsidy, Drip Irrigation normal dry drought

25 Lessons Learned: Ag Water Conservation Farmers seek income, not conservation. Conservation must be profitable for irrigators to do it. –Subsidizing water conserving irrigation technology will reduce water applied per unit land for a given crop –Reduced water applied doesn’t always reduce water depleted by crops, esp if yields increase –Requiring sustainable reservoirs and aquifers in NM can reduce the use of drip irrigation.

26 Policies that promote sustainable water use in Paso Del Norte Area Complete water rights adjudications: provides clear definition of water rights –Surface water. Esp important in droughts –Groundwater. Limits unsustainable pumping Remove restrictions on water trading Trading and water pricing –Two tiered urban pricing: promotes conservation –Publicize water prices –Publicize water right prices –All signal cost of using water for low valued uses Guard against weak conservation programs

27 Lessons Learned: Research Challenges Water conservation is hard to define, measure, forecast, evaluate, alter. Counterfactual: How much less water would have been (will be) used if X irrigation technology would have been (is) subsidized.

28 Top 10 Lies told by Watershed Policy Modelers 1.The model is well-documented with all limits 2.The model is user-friendly 3.The model fits the data 4.Results make sense 5.The model does that 6.We did a sensitivity analysis 7.Anyone can run this model 8.This model links to other models 9.The model will be in the public domain 10.The new version fixes all previous problems