economics of water supply, demand, and conservation in the paso del norte region frank a. ward
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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, 2011 12:30 – 12:50 pm. Road Map. - PowerPoint PPT PresentationTRANSCRIPT
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Sustainability on the Border: Water, Climate, and Social Change
in a Fragile LandscapeThe University of Texas at El Paso
Economics of Water Supply, Demand, and Conservation in the Paso del Norte
RegionFrank A. Ward
NM State UniversityMay 18, 2011
12:30 – 12:50 pm
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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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Basin Scale ChoicesWatershed runoff
Reservoir
Irrigated crops
Flooding
Urban water supply
Groundwater
Fish and wildlife
Treaty obligation
Hydropower
Compact Obligation
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Rio Grand
e Basin
Journey down the Rio Grande
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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
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High Valued Uses of Water in RGB, Albuquerque, El Paso
High Valued Use: Rio Grande Silvery Minnow
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High Uses of Water in RGB, Irrigation
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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)
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Policy Debates Basin Models Can Inform
• Maximize– Objective
• Economic• Environmental• Social Justice• Hydrologic
• Subject to – Constraints
• Hydrologic• Agronomic• Institutional• Economic
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Basin Model (Optimization)
Policy Assessment Framework
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Data
Headwater supplies
Min FlowsSharing rulesOutflows
Crop pricesCrop costsWater priceTreat costElasticitiesLand supply
Outcomes
Crop prodnCrop 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)
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Water Balance
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Crop Water Use Data, RG Basin, NM
Crop Tech
A ET DP
Yield tons/a
cTech
A ET DPYield
tons/acac-ft/ac/yr ac-ft/ac/yr
Alfalfa f 5.0 2.2 2.9 8.0 d 2.7 2.7 0.0 10.0
Cotton f 2.8 1.2 1.6 0.4 d 1.5 1.5 0.0 0.5
Lettuce f 2.5 1.1 1.4 12.5 d 1.4 1.4 0.0 15.6
Onions f 4.0 2.3 1.7 16.9 d 2.9 2.9 0.0 21.1
Sorghum f 2.0 0.9 1.1 2.0 d 1.1 1.1 0.0 2.5
Wheat f 2.5 1.1 1.4 4.6 d 1.4 1.4 0.0 5.8Green Chile f 4.6 2.0 2.6 11.0 d 2.5 2.5 0.0 13.8Red Chile f 5.0 2.2 2.9 1.7 d 2.7 2.7 0.0 2.2Pecans f 6.0 2.6 3.4 0.6 d 3.2 3.2 0.0 0.7
NM Pecans: Water Balance
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Drip 6’
2.6’
3.4’
Flood
3.2’ 3.2’
0
0
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A Peek at the Model
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Objective
(1 ) (1 )ut ett t
u t e tu e
NBu NBeMax NPV
r r
• 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)
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Constraints
• E.g.: Lobatos gauge (CO-NM border): X(Lobatos_v,1) = X(RG_h,1) - X(SLV_d,1) + X(SLV_r,1)
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hv ht vv dvh v d
vt vt dt
rt LLr L
trv v
B X B BX X X
XB B X
Gauged Flows: Hydro Balance
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( , , ,...)
ut uck ucktc k
X B L
u irrigated region
c crop
k irrigationtech flood drip pivot
Ag water use
•Ag Water Use and Savings–Water Supply (normal, dry, drought)
–Ag water Conservation Subsidies (low to high)
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Results of Ag Water Conservation Policy Analysis
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Water Use by Technology and Policy
LRGB (AF/yr, ET)
Tech UnitsBase
Alternative 1: Sustaining
Natural Capital
Alternative 2: Renewing Natural
Capital
use use change use change
Floodabsolute 146,266 94,917 -51,349 94,375 -51,891
pct 100 65 -35 65 -35
Dripabsolute 52,604 4,402 -48,202 1 -52,602
pct 100 8 -92 0 -100
Totalabsolute 198,869 99,318 -99,551 94,376 -104,493
pct 100 50 -50 47 -53
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Economic Value of Water by Water Shortage and Drip Irrigation Subsidy, Rio Grande Project, USA, $ / Acre Foot for Water Depleted
Water Supply Scenari
o
% Capital Subsidy, Drip Irrigation
0 25 50 75 100
normal 0.00 8.53 17.07 25.60 34.13
dry 52.50 60.05 68.59 77.35 86.58
drought142.8
5 146.83 154.48 162.16 170.13
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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.
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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
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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.
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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