Eastern Snake Plain Comprehensive Aquifer Management Plan

A Positive Path Forward

Hal N. Anderson

June 11, 2009

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Regionally Averaged Cool Season Anomalies

(Source-U.W. Climate Impacts Group)

Eastern Snake Plain Aquifer Model Water Budget

Sum of Historic Diversions: Snake River abv King Hill

5,500

6,000

6,500

7,000

7,500

8,000

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10,000

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ANNUAL DIVERSION

4 YEAR MOVING AVERAGE

AVERAGE ANNUAL SPRING DISCHARGE TO SNAKE RIVER BETWEEN MILNER AND KING HILL

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Background • ESPA Framework Plan Process Initiated 2006, by SCR

136.• ESPA Framework Plan Developed and Adopted in 2007,

HCR 28.• Advisory Committee Convened (2007) • ESPA Advisory Committee Recommendations

Developed (2008)• Board Adoption of the ESPA Plan, January 29, 2009.• 2009 Legislature approved HB 264 approving ESPA

Plan, Governor signed into law April 23.

Framework Plan

Recognized that water supply and demand were out of balance in the aquifer and the Snake River, making more deliberate and coordinated management of surface and ground water on the ESPA a necessity.

Objectives for ESPA Management• Increase predictability for water users by

managing for reliable supply.

• Create alternatives to administrative curtailment.

• Manage overall demand for water within the Eastern Snake Plain.

• Increase recharge to the aquifer.

• Reduce withdrawals from the aquifer.

Historic Flow Volume: Snake River at King Hill

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ANNUALFLOW

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Historic Flow Volume: Snake River at Milner

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ANNUALFLOW

4 YEAR MOVING AVERAGE

Management Options Components Estimated Average

Supply (best information)

Estimated Cost (best information)

Hydrologic Impacts Timeline for implementation

Weather Modification (Idaho only)

60,000-190,000 AF/yr (increase yield by 3.5- 7%)

$250k -$700k/yr Potential supply increase in headwater snowpack. Increased natural flow, and increased reservoir storage.

1-to-2 years

Aquifer Recharge (no construction option – use excess natural flow for supply)

70,000 AF/yr

(50 KAF from Snake and 20KAF from Wood)

$8/AF wheeling fee ($560,000/yr)

No capital cost

Above American Falls – improved natural flow later in season. Some improvement to reaches above and below Milner with current facilities at NSCC and Wood River system

1 year

Salmon flow exchange

102,000 AF/yr (varies from 0-to-205KAF based on water supplies)

$185M up-front cost (need to acquire 205KAF+20%, assume $750/AF)

Increase in storage availability for conversion or recharge projects. Reduces releases past Milner.

5 years due to water right purchases

Costs are preliminary estimates for budget purposes only

Management Options Components Estimated Average Supply

(best information)Estimated Cost (best information) Hydrologic Impacts Timeline for

implementation

Minidoka Enlargement 50,000 AF/yr $250M capital cost

Annual O&M at 1% of capital cost ($2.5M/yr)

Reliable Storage supply for conversion, recharge or other projects

10 years

New Storage above American Falls

100,000 AF/yr $500M capital cost

Annual O&M at 1% of capital cost ($5M/yr)

Reliable Storage supply for conversion, recharge or other projects

30 years

Aquifer Recharge - Infrastructure required - using excess natural flow

400,000 AF/yr $75M

Annual O&M at 1% of capital cost ($750K/yr)

Annual wheeling costs of $8/AF ($3.2M/yr)

The majority of the capital cost would have to be spent below American Falls

Recharge spread over broader area, longer term improvement to reach gains/aquifer levels above and below Milner

20 years due to construction

A&B Conversion requires Minidoka enlargement and Salmon Flow Exchange to provide water supply

Partial conversion of District may be an option

$350M capital cost

Annual O&M at 1% of capital cost ($2.5M)

Also see costs under Minidoka Enlargement and Salmon Flow Exchange

Cost of partial conversion would be proportional.

Reduces pumping stress in a key location; long term improvement to reach gains/aquifer levels evenly distributed above and below American Falls

10 years

Costs are preliminary estimates for budget purposes only

Management Options Components Estimated Average Supply

(best information)Estimated Cost (best information)

Hydrologic Impacts Timeline for implementation

Other Hard Conversions (Hazelton Butte)

20 KAF (10,000 acres+/) Requires Salmon flow exchange and/or Minidoka for water supply

$20M capital cost

Annual O&M at 1% of capital cost ($200K)

Also see costs under Minidoka Enlargement and Salmon Flow Exchange

Improvements in reach gains below Milner, however results could be intermittent depending on surface supply

10 years

Soft Conversions requires Salmon flow exchange and/or Minidoka for water supply –

Full implementation requires salmon flow exchange

$23M capital cost

Assume annual O&M cost is borne by landowners

Long term improvements in reach gains above Milner, however results are not immediate and could be intermittent depending on surface supply

5 years

Demand Reduction

- dry year lease

- fallowing

- buy outs

- crop mix changes

160 KAF (have already achieved 40 KAF thru CREP)

$1,250/AF for acquisition of ground water rights

Other options should be less

Buy-outs would have a permanent impact to water budget through reduced depletions – other options depend on configuration of programs

2-10 years depending on options and amounts

Costs are preliminary estimates for budget purposes only

Weather Modification is a stand-alone option to be considered

independently of packagesOption Estimated Average

Supply (best information)Estimated Cost (best information)

Timeline for implementation

Weather Modification

60,000-190,000 AF/yr $250k-$700k/yr 1-to-2 years

Costs are preliminary estimates for budget purposes only

Weather Modification Feasibility Study Estimated Streamflow Increases

Management Alternative Packages

Packages Developed include:– Small (300 KAF); least expensive and

quickest to implement– Medium (600 KAF); more expensive and

takes more time to fully implement– Large (900 KAF); most expensive and will

take decades to fully implement– Demand Reduction and Recharge Emphasis

Hydrologic Goal – 600 kaf Change

– 600 kaf Water Budget Change

• Robust mix of conversions, aquifer recharge, demand reduction and conservation strategies

– Implementation Timeline – 20 years

– Cost – $600 million not including O&M

Phase I ActionsPhase I (1 – 10 years)

• Hydrologic target of 200kaf – 300kaf

• Initiate actions that increase aquifer levels, and spring and river flows

• Geographically distributed across the ESPA

• Build institutional confidence with long-term plan implementation

Phase I Actions

– Groundwater to Surface Water Conversions

– Managed Aquifer Recharge

– Demand Reduction • Buyouts, buy-downs and/or subordination agreements• Rotating fallowing, dry-year lease agreement, CREP• Crop mix modification • Surface water conservation

– Pilot Weather Modification Program

PLAN HYDROLOGIC TARGETS

Action Phase I Target (kaf) Long-Term Target (kaf)

Ground Water to Surface Water Conversion

100 100

Managed Aquifer Recharge 100 150-250

Demand Reduction 250-350

Surface Water Conservation 50

Crop Mix Modification 5

Rotating Fallowing, Dry-Year Lease Agreements and CREP Enhancements.

40

Buy Outs, Buy Downs, and/or Subordination Agreements

No Target (Opportunity-Based)

Weather Modification 50* No Target

TOTAL 200-300

600

CAMP Hydrologic Targets

* 50kaf based on conservative estimate from Upper Snake Weather Modification Feasibility study

Action Water Budget Change

Capitol Cost Ongoing Annual Cost

Cost per Acre-foot of benefit

Ground water-to-surface water conversions

100 KAF $30M (1) $300/AF

Recharge 100 KAF $15M $300K/yr equals $3M for years 1-10

$180/AF

Weather Modification 60 KAF– 190 KAF $700K/yr equals $7M for years 1-10

$50/AF

Surface Water Conservation in areas not impacting recharge to ESPA

50 KAF $20M (1) $400/AF

Crop Mix Modification 5 KAF $1M/yr equals $10M for years 1-10

$200/AF

Rotating fallowing, dry year leasing, CREP

40 KAF (2)

Program Administration and engineering

$5M over years 1-10

TOTALS 355 KAF – 485 KAF

$65M $25M over years 1-10

$227/AF

Notes :(1)It is assumed that the water users will take over annual O&M in these cases since these projects should reduce O&M costs from existing levels. (2) CREP has already achieved a 40 KAF water budget change so no additional costs are needed for this action unless CREP acreage decreases.

ESPA CAMP Phase 1 ACTIONS - COST PER ACRE FOOT OF BENEFIT

ESPA CAMP Hydrologic Analysis

A series of hydrologic analyses were conducted to determine the effects of the CAMP Phase 1 actions on aquifer levels and reach gains (spring flows) from the aquifer. The period of 1980-2005 was used as hydrologic input into the analysis. It was determined that over this time period, the Phase 1 CAMP actions could be achieved as follows:

Phase 1 CAMP Action Average acre-feet/year

Recharge (Snake River) 91,223

Recharge (Wood River) 22,565Conversions 85,027Surface Water Conservation 32,100Weather Modification 51,500Demand Reduction 44,835

TOTAL 327,250

ESPA CAMP Phase 1Estimated Increase in Reach Gains (Spring Flows) from the Aquifer at Selected Locations

Blackfoot to Neeley

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ESPA CAMP Phase 1Estimated Increase in Ground Water Levels at Selected Locations

Near American Falls Reservoir

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ESPA CAMP Phase 1 Funding Participation Targets

Water User Category Phase 1 Funding Participation Targets

Irrigated Agriculture$3 million annually (based on participation of $2 million annually for

ground water users and $1 million for surface water users)

Idaho Power$1 million - $1.5 million annually (for projects that qualify for

TEMP)*

Municipalities$700,000 annually (includes commitment to address rules and

statutes that may inhibit municipal growth)

Spring Users $200,000 annually (based of cfs)

Industrial and Commercial Users(not served by municipalities or ground water districts) $150,000 annually (based on estimated 15kaf use annually)

State of Idaho $3 million annually

FederalPursue federal grant and cost share funding opportunity; EQUIP,

Water for America, CREP and others

Recreation/Conservation Pursue grants and other funding opportunities

* Temperature Enhancement and Management Program

Select Additional Plan Components • Designed to enhance coordination, decision making and

aquifer management.• Environmental considerations, will seek to optimize

outcomes for fish and wildlife, recreation, hydropower, municipalities, irrigation, aquaculture and other uses.

• Clearinghouse, a flexible mechanism to connect willing participants.

• Outreach and Education, initial emphasis on local governments, domestic well owners and consumptive water users.

• Management Flexibility and Innovation, consider innovative strategies to solve water management problems.

Comprehensive Aquifer Management and Planning Program

• 2008 Legislation• House Bills No. 428 and 644• Created Aquifer Planning and Management

Program• Established Aquifer Planning and Management

Fund• New Idaho Code Sections: 42-1779

42-1780

Purpose

• Conduct statewide comprehensive aquifer planning and management effort over a 10-year period

• Avoid the Eastern Snake Plain conflicts in other areas of the state

• Develop management plans for selected basins with potential ground-surface water conflicts or other potential conflicts

Funding• 30 million dollar program to study and develop

Comprehensive Aquifer Plans for 10 Major Aquifers.• Legislature Appropriated $20 million in FY2009.• Appropriated $274,900 to IDWR for first year of

program• Interest from Fund will be routed back into Fund to

extend funding for duration of program• Governor Recommended using $12 million in FY2010

to offset General Fund Shortage.• Remaining $8 million will fund completion of

Rathdrum and Treasure Valley Aquifers and ESPA Monitoring through FY 2013.

Original Schedule of Work Based on $20 Million (plus interest)Basin FY 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

ESPA Monitoring

Treasure Valley

Rathdrum Prairie

Palouse

Big Wood

Mountain Home

Bear

Teton

Big Lost

Portneuf

Blackfoot

Revised Schedule of Work Based on $8 Million (plus interest)

BasinFY 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

ESPA Monitoring

Treasure Valley

Rathdrum Prairie

Comprehensive Aquifer Management and Planning

Ten

Priority

Aquifers

Anticipated Technical Studies

• Establish Monitoring Network • Develop Hydrologic Framework• Water Balance• Ground Water Model• Climate Change and Weather Modification

feasibility.• Storage Opportunities

Anticipated Planning Studies

• Water Demand Projections (50 year)• Facilitators have been hired for Rathdrum and

Treasure Valley.• Evaluate alternatives to meeting projected

demands:– Water Use Transfers (i.e., ag to DCMI)– Weather Modification Feasibility– Aquifer Recharge– New Storage – Inter-basin Transfers

Questions ?