Panhandle Water

Planning Area

Alternative Approaches

Consideration of Legal Constraints in Demand Development

Demands

MAG

Supply

MAG

Supply

with

buffer

Panhandle Water

Planning Area

PANHANDLE APPROACH TO

IRRIGATION SUPPLIES

2011 Panhandle Area Regional Water Plan

Panhandle Water

Planning Area

Source Availability

� Ogallala Availability

� 40/50/80 Approach

� 2004 Northern GAM Model

� Calculated for each 1 sq mi grid

� Rita Blanca

� Included as part of Ogallala

� Dockum, Seymour, Blaine

� 1.25% decline in storage

� Reservoirs

� Safe Yields

Panhandle Water

Planning Area

Supply to WUGs / WWPs � Consider most limiting factor

� Geographical constraints

� Infrastructure

� Contracts

� Consider source

� Location

� Availability

� Quality

Panhandle Water

Planning Area

Comparison of Supply to Demand

Panhandle Water

Planning Area

Comparison of Supply to Demand

� 27 WUGs with Identified Shortages

� 454,726 Acre-Feet in 2010

� 487,957 Acre-Feet in 2030

� 419,780 Acre-Feet in 2030

� 99% attributed to Irrigation in 2010, 91% in 2060

� Limitations of availability in irrigation areas

Panhandle Water

Planning Area

2009 InteraGAM

Differences in Available Supply from 2004 Dutton GAM

Panhandle Water

Planning Area

COMPARISON OF MAGS, AVAILABLE

SUPPLIES AND IRRIGATION DEMANDS

2011 Panhandle Area Regional Water Plan

Panhandle Water

Planning Area

Irrigation Supplies

0

100,000

200,000

300,000

400,000

500,000

600,000

Dallam Hartley Sherman Moore

Groundwater Supplies, Year 2010

2004 Dutton GAM Intera GAM MAG

Irrigation Demand Irrigation Supply

Panhandle Water

Planning Area

Irrigation Supplies

0

100,000

200,000

300,000

400,000

500,000

600,000

Dallam Hartley Sherman Moore

Groundwater Supplies, Year 2060

2004 Dutton GAM 2009 Intera GAM MAG

Irrigation Demand Irrigation Supply

Panhandle Water

Planning Area

Discussion� Do we limit demands based on

supplies?

� No demand > MAG

� Do we modify approach to assigning irrigation supplies?

� Are there other demand considerations?

Panhandle Water

Planning Area

METHODOLOGY FOR ASSIGNING

WATER SUPPLY

Agricultural Water User Groups

Panhandle Water

Planning Area

Supply to Ogallala WUGs

� Used GAM to assist with irrigation and municipal users

� Irrigation Users

� Lesser of GAM or demands

� Livestock Users

� Met demands

� Greater flexibility in moving to areas with water than irrigated agriculture

Panhandle Water

Planning Area

Irrigation Zones

Panhandle Water

Planning Area

Irrigation Supplies-Current Methodology

� Conservative Approach

� 1 mi2 grid – competition for water

� Limits supply in time and space

� 54 one-year simulations

� Water will flow to irrigation wells from outside grid area (how far?)

� May not correspond to GCD permitting

Panhandle Water

Planning Area

Irrigation Supplies-Current Methodology

� Captures intent of DFC

� Limits geographical extent of supply allocation

� Allows additional supply to be developed by others

� Protects other landowner rights

� Simply a plan

� No legal implications

Panhandle Water

Planning Area

Discussion� Do we modify approach to

assigning irrigation supplies?

� Continue to use GAM?

� Add a buffer?

� Modify temporal supplies (e.g., allow more use early in the planning period)?

� Do we modify approach to assigning livestock supplies?