New Mexico Water Dialogue Upstream-Downstream Project Workshop #1 - - PowerPoint PPT Presentation

New Mexico Water Dialogue Upstream-Downstream Project Workshop #1

June 26, 2006

The physical problem, and do the regional water plans address it?

S.S. Papadopulos & Associates, Inc.

The Middle Rio Grande Water Supply

• For ACOE and NMISC, SSPA conducted

the MRG Water Supply Study (2004)

• To evaluate the water supply from

Cochiti to Elephant Butte, under the limits of the Rio Grande Compact,

• Considering surface water and

groundwater, in a probabilistic context.

Questions addressed in the Probabilistic Water Supply Study

• How much water is theoretically available for use in the

Middle Rio Grande region?

• Where are depletions to the supply occurring?
• How will the depletions and supply change in the future,

with implementation of the regional water plans?

• How will Compact deliveries be impacted,

both in the present and in the future, under conditions of extended drought?

The Water Supply is…...

• Variable
• Limited

Annual Variability:

Otowi Index Supply, 1950-2002

500,000 1,000,000 1,500,000 2,000,000 2,500,000 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Flow (acre-ft/year)

Limits:

Flow at Otowi Bridge available to NM, 1950-2002

50 100 150 200 250 300 350 400 450 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Water avail to NM (af/year)

Method: Evaluation of Physical Supply

• A simple water budget model was constructed to

represent water inflow and outflow, for surface water and groundwater in the Middle Rio Grande region.

• The natural variability in the water supply was addressed

by applying a probabilistic analysis to the water budget.

• The water budget compares supply to demand and

describes the residual as Rio Grande Compact credit/debit

• Changes proposed by regional water plans were evaluated.

WATER BUDGET SCHEMATIC: STREAM SYSTEM

Native Inflow Flow from Change in Storage Import Water (San Juan – Chama) Inflow Gage at OTOWI

Gaged Tributary Inflow Depletion Due To Pumping/ Groundwater Interaction Wastewater Returns Irrigation Consumption Ungaged Tributary Inflow Riparian Consumption Evaporation

Outflow Gage: Rio Grande Below Elephant Butte

Rio Grande Compact Credit/Debit Relationship

Inflow Terms - Averages

• Otowi Index Supply

945,000 af/year

• San Juan Chama Water

81,005 af/year

• Jemez River

44,400 af/year

• Santa Fe River

9,580 af year

• Galisteo Creek

4,200 af/year

• AMAFCA inflow

9,500 af/year

• Rio Puerco

25,800 af/year

• Rio Salado

10,500 af/year

• Ungaged Tributaries

28,300 af/year

• Wastewater inflow

66,800 af/year

• Effective Precipitation

50,200 af/year

Depletions

• Groundwater Depletions
• Open Water Evaporation
• Agricultural Consumptive Use
• Riparian Evapotranspiration

Given a typical range of climate conditions, and present levels of water use, an average debit condition is projected

Note: annual depletions from groundwater storage are represented by yellow arrow

Average Base Case Modeling Results

Key Steps in Probabilistic Water Supply Analysis

• Using historical observations,

fit a probability distribution function to water budget terms influenced by climatic variabilty

• Identify dependent

relationships

• Use probabilistic analysis to

describe the water supply

Statistical Distribution: Rio Puerco

Probability plot - Rio Puerco, 1950-2002

20,000 40,000 60,000 80,000 100,000 120,000 10 20 30 40 50 60 70 80 90 100 Percent less than

Rio Puerco Flow Lognormal distribution

Rio Puerco A nnual Flow (1950-2002)

40,000 80,000 120,000 1950 1960 1970 1980 1990 2000 Y ear Flow (acre-ft/ye

Probability Distribution of Projected Compact Credit/Debit

Present Development Condition, 2000

• 250,000
• 200,000
• 150,000
• 100,000
• 50,000

50,000 100,000 150,000 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 Percentile rank within Distribution Compact Credit/Debit (af/year)

What water budget model is not projecting:

• Reproduction of historic period
• Prediction of specific future events or outcomes
• Flow in river channel at basin mid-points
• River / reservoir operations

Summary of Mean Depletions, Grouped by Use

Note: Shown are percentages of total mean river depletions of approximately 680,000 acre-feet per year Additional depletions of 71,000 acre- feet per year are presently occurring to aquifer storage. Mean depletions to River System (acre-feet/year) Year 2000 Land Use and Groundwater Development Conditions

26% 37% 9% 3%

Agriculture Riparian Open Water Reservoir Evaporation Urban

25%

Summary of Mean Depletions, Grouped by Geographic Section

Note: Shown are percentages of total mea river depletions of approximately 680,000 acre-feet per year. Additional depletions of 71,000 acre-feet per year are presently occurring to aquifer storage. Mean depletions to River System (acre-feet/year) Year 2000 Land Use and Groundwater Development Conditions

10% 27% 26% 38%

Section 1, MRGPR Section 2, SSPR Section 3, SSPR Reservoir Evaporation

• Groundwater depletions (impacts on river from

pumping) for Cochiti to San Acacia obtained from 2002 USGS Albuquerque Groundwater Model.

• Cochiti to San Acacia pumping depletions:

79,600 af/year

• Santa Fe pumping depletions: 2,676 af/year
• Socorro pumping depletions: 3,300 af/year

Groundwater Depletions

20 40 60 80 100 120 140 1900 1925 1950 1975 2000 2025 2050 2075 2100 Acre-Ft Per Year (x 1,000)

Model Derived Surface Water Depletions from Groundwater Pumping, Albuquerque Basin

(USGS Albuquerque Basin Groundwater Model, 2002) Year 2000 depletions Lagged impact on river of continued pumping at Year 2000 rates

40,000 80,000 120,000 160,000 200,000 240,000 280,000 1945 1955 1965 1975 1985 1995 2005 Year Evaporative Losses (af/y) Lake Surface Evaporation Riparian Vegetation Evapotranspiration Adjusted Elephant Butte Losses

Depletion at Elephant Butte Reservoir

• Average evaporative and riparian ET losses

within reservoir boundaries, 1950-2002, 164,000 af/year

Agricultural and Riparian Consumptive Use

• Average Riparian ET:

247,000 af/year

• Average Agricultural CU:

180,000 af/year

Uncertainty and Sensitivity Analyses

• Uncertainty in several large water budget terms exists
• Acres irrigated
• Agricultural consumptive use
• Riparian consumptive use
• Ungaged inflow
• Effective precipitation
• Sensitivity analyses

show that error bar in basin depletion estimates may span 5% to 10% of total

How will Compact deliveries be impacted given implementation of regional water plans?

• Assess base case scenario (Year 2000 development

conditions)

• Evaluate alternatives posed by the Socorro-Sierra and

Middle Rio Grande Planning Regions (with water use projected to 2040)

• Evaluate water supply and demand conditions under the

combined Jemez y Sangre/ Middle Rio Grande/ Socorro- Sierra planning alternatives

• Evaluate using inflow conditions as seen historically and

given extended drought

Middle Rio Grande Planning Region “Preferred Scenario” (March 2004)

• Implementation of City of Albuquerque Drinking Water Plan
• Municipal/Industrial conservation initiatives
• Importation of 22,500 af/y of desalinated water
• Retirement of 25% of agricultural lands within MRGPR

boundaries (11,073 acres => 33,000 af/y reduction in CU)

• Retirement of 7,500 acres of agricultural lands within SSPR

boundaries (21,000 af/y reduction in CU)

• Restoration of 34,500 acres of bosque (34,500 af/y

reduction in CU)

Modeled MRGPR Year 2040 Municipal/ Industrial Demand

N/A

• 32,437

Change in GW storage depletions 31,556

• 315

Change in GW river depletions Increase in CU of 78,890 Net surface water impact 41,351 Increase in WW returns to river N/A 89,000 Direct diversion of surface water Non-City of Alb Demand (af/y) City of Alb Demand (af/y)

Rio Grande Depletions from Pumping

20 40 60 80 100 120 1900 1920 1940 1960 1980 2000 2020 2040 2060 Year Depletions in River (af/year)

Year 2000 Pumping City of Alb DWP

Socorro-Sierra Planning Region (SSPR) proposed alternatives

• Improve conveyance efficiency
• Improve on-farm efficiency
• Control brush and weeds

Combined; reduces agricultural CU by 5% (2,768 af/year)

• Evaporation control
• Elephant Butte Reservoir
• Elsewhere in region – 1,649 af/year CU decrease (10% reduction)
• Remove exotic

vegetation 4,060 to 20,300 af/year CU decrease (10-50% removal)

Jemez y Sangre Planning Region (JySPR) Alternatives

• The JyS Regional Water Plan was reviewed; Year 2040

elements impacting the water supply below Otowi gage were identified as:

• 8,730 af/y increase in depletions arising from implementation
• f the Buckman Direct Diversion plan;
• 11,000 af/y increase in depletions arising from full utilization
• f allocated SJC water(between 1999 and 2003 this water

was leased to the Bureau).

• Additional Year 2040 regional demand assumed to be

met through conservation.

Joint Analysis SSPR, MRGPR, and JySPR

Reduced by 12,000 af/year Elephant Butte evaporative losses Reduced by 37,800 af/year SSPR riparian ET Reduced by 17,000 af/year MRGPR riparian ET Reduced by 37,511 af/year MRGPR agricultural CU New depletion term of 31,556 af/year MRGPR additional non-CofA M&I demands New depletion term of 89,000 af/year MRGPR municipal surface water withdrawals Increased by 41,351 af/year MRGPR wastewater returns New inflow term of 22,500 af/year MRGPR inflow from desalination New demand term of 19,730 af/year Utilization of additional water within JySPR

Key Initiatives:

Joint analysis results

• Year 2040 average Compact Debit of 7,100 af/year
• However….
• 39,600 af/year of groundwater pumping is not yet

impacting river;

• Requires restoration of 54,500 acres of riparian

vegetation, resulting in a 1 acre-foot per acre per year increase in available water;

• Assumes retirement of over 11,000 acres of agricultural

land with no further water use by those lands.

Unrealistic Assumptions?

• Can ag land (more than 11,000 acres) be retired such

that it uses no water other than precipitation?

• Will the City of Albuquerque be able to take/use

surface water at the rates modeled?

• Will the City of Albuquerque be able to obtain 22,500

acre-feet per year of desalinated water?

• Will restoration of native riparian vegetation be as

effective at freeing up water as we modeled?

New Mexico Riparian Evapotranspiration Rates from the Recent Literature 3.22 Mature cottonwood w/closed canopy*** 4.03 Mature cottonwood w/extensive understory*** 2.97 Sparse cottonwood* 2.43 to 2.49 Less dense salt cedar*** 3.64 to 4.0 Dense salt cedar*** 2.43 to 4.0 Salt cedar at multiple sites** 4.35 Dense salt cedar* ET rate (ft/year) Vegetation Type

Table 2.4, Riparian Groundwater Models for the Middle Rio Grande: ESA Collaborative Program FY04, SSPA 2006

* King and Bawazir, 2000 ** Cleverly et al., 2002 *** Dahm et al., 2002

Conclusions

• On average, the historically available water supply is not

adequate (including San Juan-Chama Project water and groundwater withdrawals) to meet the present demands in the Middle Rio Grande region.

• Assuming implementation of regional water planning

alternatives, Compact deliveries are significantly improved, with Compact deliveries being met at the 50th

• percentile. However, implementation of the joint

alternatives as proposed and included in the planning region reports will be challenging, if feasible.

If feasible:

This joint alternatives analysis assumes

• the region will salvage 1 acre-foot of water

per acre by removing salt cedar

• 11,000 acres of agricultural land will be

retired without incurring ANY water use from these lands (i.e. they will not be colonized by either native or non-native riparian growth)

Conclusions

BOTH of these assumptions may be physically unachievable.