SNAKE RIVER GROUND WATER TRANSFERS

Climate Impacts Group

May 13, 2003

Don Reading

Richard Slaughter

I. The Setting

Snake River Basin

1000 Springs Flows

Idaho Water Markets• Rental Pools - storage water; local committees and

tribe– Water District 1 (Upper Snake)

– Water District 63 (Boise)

– Water District 65 (Payette)

– Shoshone Bannock (American Falls & Pocatello)

• Water Supply Bank - Natural Flow (both surface and ground)– IDWR Board/Director

• Transfers (both surface & ground)– IDWR Board/Director

II. The Problem

No more ignoring the obvious: Idaho sucks itself dry

High Country News - February 20, 1995

Water Level Change In Feet

Idaho Falls

Pocatello

Twin Falls

Arco

Ashton

-25

-20

-15

-10

-5

0

5

10

15

Eastern Snake River PlainGround Water Level Change MapSpring of 1980 to Spring of 2002

Water Level Change In Feet

Idaho Falls

Pocatello

Twin Falls

Arco

Ashton

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

Eastern Snake River PlainGround Water Level Change Map

Spring of 2001 to Fall of 2001

“Calls”

A “Call” is a request by a water right holder to fulfill the full amount of their water right.

A. Musser Call (1993) B. A&B Irrigation Call (1995) C. IDWR ‘Curtailment’ & Stipulation (2001)

1. Basin 35 – Twin Falls, North Side

2. Basin 36 – Clear Springs Foods

III. The Solution

Modification of Market Rules

North Snake Ground Water District Project

IDWR Ground Water Model

EASTERN SNAKE RIVER PLAIN HYDROLOGIC EFFECTS SPREADSHEET

Developed by D. Cosgrove and G. Johnson, Idaho Water Resources Research Institute, University of Idaho with support from the U.S. Bureau of Reclamation's Snake River Resources Review ProjectJune, 2000

Purpose and Scope

This spreadsheet has been developed to assist in conjunctive management of Idaho’s water resources.

The spreadsheet provides quantitative estimates of the effects associated with ground water pumping and managed recharge in the Eastern Snake River Plain.

Effects are reflected as changes in spring discharge or river gains and losses in the Snake River between Heise (or Ashton on the Henrys Fork of the Snake River) and King Hill.

Numerical Example of Ground Water Transfer

Effect within reach – year of transfer (acre feet)

Withdrawal Aquifer Depletion

“FROM” Well 100 50

“TO” Well 100 60

“FROM” well cease production“TO” well may or may not begin withdrawal

Hydrologic Response--Neeley to Minidoka Reach

-8.000

-6.000

-4.000

-2.000

0.000

2.000

4.000

6.000

8.000

Acre

Fee

t per

Trim

este

r

Net Effects

Pumping Effects

Recharge Effects

Effect within reach – 10 years after transfer

Withdrawal Aquifer Depletion

“FROM” Well 100 30

“TO” Well 100 60

Aquifer depletion in year 10 90

Therefore net aquifer depletion – in year 10 is 40 acre feet

[Original 50 “FROM” well & 90 in year 10 ; 90 – 50 = 40]

Therefore in year 10 need “make-up” water of 40 acre feet

What can the “TO” well pump in year 10 ?

Let the reduction in the “TO” well by R

40 acre feet needs to be “made-up”

Therefore:40 = .6*R

or R = 40/.6 = 66.67

Hence the purchaser of the “TO” well can withdraw 33.33 acre feet in year 10; but would have purchased 100 acre feet.Each year may be different.

•“TO” well may be idle for “X” years after transfer.

•After “Z” years the system will be assumed stable.

•Credits may accrue to out of reach gains.

Water Price Differences (acre foot)

• Idaho Rental Pools and Bank: $2.95 - $10.50

• BoR fish flush: $50 - $100

• Metro Water of Southern California: $82 - $294

• Desalination: $1,500 - $2,500

• Grand Canyon vacation home development: $16,800

Gross Revenue from 1 AFSnake River Plain

• Aquaculture $14• Surface diversion for agriculture $100• Groundwater for agriculture $200• Groundwater for municipal $400 • Groundwater for Dairy $45,000• Groundwater for industrial > $50,000

Improved Economic Efficiencies

• Eliminates third party effects

• Reduces transactions costs

• Adds certainty for purchaser and seller