Transcript No Slide Title

RiverWare User’s Group Meeting
Pecos River Adjudication
Settlement: Application of an
Integrated Surface and Ground
Water Modeling System
June 18, 2003
Presentation Outline
• Overview of Pecos River Institutions /
Operational Policies
• Adjudication Settlement: Problems and
Solutions
• The Pecos River DSS
• Evaluating the Settlement Terms
• Conclusions
Institutions and Operations
• Pecos River Compact and Amended Decree (New
Mexico / Texas)
• Water Rights - Prior Appropriation Doctrine;
adjudication and administration
• ESA operations for Pecos Bluntnose Shiner
• 2 NEPA EIS programs
• Carlsbad Project (reservoir operations, GW
diversions)
• Other diverters (FSID, river pumpers, M&I, etc)
• PVACD groundwater diversions
Santa Rosa Reservoir
Major
Irrigators,
Physical
Features,
and
Critical
Resource
Locations
in the
Pecos
Basin
Sumner Reservoir
Fort Sumner Irrigation District
Pecos Valley Artesian Conservancy District
USGS gage PR @ Acme
Brantley Reservoir
Carlsbad
Irrigation
District
NM - TX State Line / Pecos River Compact
Pecos Adjudication Settlement
• Parties: PVACD, CID, NM ISC, United States
• Purpose:
– Ensure long-term compliance with the Pecos River
Compact and Amended Decree
– Avoid need for priority administration of water rights
– Maintain or enhance water supplies / aquifer storage levels
• Proposal:
– NM ISC purchases water rights / land from PVACD and CID
– CID water delivered to state line for Compact deliveries
– PVACD lands retired, water provides augmentation supply
when needed
Pecos Adjudication Settlement Evaluation of the Proposal
• Use existing modeling tools to evaluate and refine
Settlement terms.
• Pecos River DSS integrates RiverWare, two
MODFLOW models, an accounting model, and
numerous I/O tools.
• “Rules” simulate baseline conditions and proposed
actions.
• Various resource indicators used to quantify “value”
of actions by comparing baseline and Settlement
model results.
Santa Rosa Reservoir
Approximate
Spatial
Domain of
Pecos
Decision
Support
System
Models
Roswell Artesian Basin
Groundwater Model
Pecos River
RiverWare
Model
Brantley Reservoir
Carlsbad Area
Groundwater
Model
Red Bluff
Accounting Model
NM / TX State Line
Pecos River RiverWare Model
• Rule-based
simulation of
Pecos River
hydrology
and reservoir
operations
from Santa
Rosa
Reservoir to
Avalon Dam
•
USBR, Tetra Tech,
Hydrosphere,
Pecos HWG
Roswell Artesian Basin
Groundwater Model
• Calibrated MODFLOW model of
groundwater flow in Roswell
Artesian Basin, in both the deep
artesian and shallow alluvial
aquifers
• Simulates areal and stream
recharge, pumping stress, Pecos
River - groundwater interaction
• Predicts base inflows to the Pecos
River
•
Amy Lewis, NM SEO (Eric Keyes), SSPA,
Hydrosphere
Carlsbad Area Groundwater
Model
• MODFLOW model that
simulates groundwater
flow in the Capitan Reef
and overlying alluvial
aquifer in the Pecos River
Basin from Lake Avalon to
the Malaga Bend
• Simulates surface-water
irrigation, groundwater
diversions, losses, and
return flows
• Predicts base inflows to
the Pecos River
•
Amy Lewis, NM SEO (Peggy
Barroll), Intera/Hydrosphere
Red Bluff Accounting Model
• Computes Monthly and Annual Flows at Red
Bluff
– Historical (Calibration)
– Current Conditions (Alternative Evaluation)
• Red Bluff Flow = Resource Indicator
– Evaluation of Policy Alternatives
– Interstate Compact Implications
• Calculation of Calibration Targets for CAGW
Data Processing Tool (DPT)
• Input/Output for Models
• Data Archiving/
Metadata
• Alternative Evaluation
and Archiving
RiverWare
Data Processing
Tool
RABGW
CAGW
RBAM
Settlement Modeling Challenges
• CID Allotment based on surface water supply (RiverWare)
• Augmentation pumping in Roswell Basin conditioned on
CID water supply: pumping occurs when CID supplies
short of 90Kaf; up to 35Kaf/year, 100 Kaf per 5-year
accounting period (Feedback from RiverWare to RABGW
model)
• Compact credit thresholds computed by Red Bluff model
drive RiverWare rules for water deliveries (Feedback from
RBAM, via CAGW, to RiverWare):
– Carlsbad Irrigation District allotment and distribution
– Delivery of water to Texas
Pecos Decision Support System:
Model Linkages
RiverWare
Res Ops
Water Delivery
Data Processing
Tool (DPT)
RABGW
CAGW
Land Retirement
Aug. Pumping
Surface water diversions
Supplemental GW pumping
Feedback Loops:
Red Bluff
Acct Model
Pecos Compact
Compact deliveries drive reservoir ops
CID Supply drives Roswell augmentation pumping
Settlement Model
Implementation
• Baseline model w/ Settlement Rules
• Iterate between RiverWare and RABGW to
determine total augmentation pumping
• Sensitivity analysis in Carlsbad GW model; results
used by RiverWare to estimate compact credit
• Simulate basin operations to state line and verify
estimates used in RiverWare
Evaluation of Settlement Terms
• Avoid priority administration (50,000 AF Supply on
March 1)
• Meet Compact delivery requirements (Stateline flows
and Compact accounting)
• Maintain or enhance CID water supply
• Maintain or enhance Roswell basin aquifer storage
levels
Resource Indicator: Roswell Basin Aquifer
Storage
Derived from RABGW Model
Layer 1 RABGW Model, Alluvial Aquifer
Predevelopment Storage ~ 17.3 million af
Simulation Start Date = Jan 1, 2000
Normalized Storage Deficit (af)
-12.0%
-12.5%
Baseline
-13.0%
Settlement
-13.5%
-14.0%
-14.5%
-15.0%
-15.5%
-16.0%
-16.5%
-17.0%
-17.5%
-18.0%
1
4
7
10
13
16
Year
19
22
25
28
Resource Indicator: CID Supply and Sources March 1 Supply - Settlement Scenario
CID Surface Water Supply - March 1
140000
Augmentation from PVACD Wells
Total Supply Deliverable at Avalon (Acre-feet)
120000
Pecos River Native Flow
100000
80000
60000
40000
20000
0
1
4
7
10
13
16
Year
19
22
25
28
Resource Indicator: Compact Obligations and
Departures: Cumulative Departure
Cumulative Compact Departure from Obligation
Initial Condition = January 1, 2000
250
Baseline
200
Total Departure (Thousands of Acre-Feet)
Settlement
150
100
Average Departure = 6,430 af/yr)
50
0
-50
-100
Average Departure = (-2,950 af/yr)
-150
-200
1
3
5
7
9
11
13
15
Year
17
19
21
23
25
27
29
Settlement Gains to Stateline Flows
Source Flow (Acre-feet)
Sources of Additional Stateline Flow under Proposed Settlement
30000
300000
20000
250000
10000
200000
0
150000
1
4
7
10
13
16
19
22
25
28
-10000
100000
ISC Release of CID Water Rights
-20000
Conservation Spills
50000
Baseflow Gains from CID Return Flows
Cumulative Gain in Stateline Flow
-30000
0
Year
What’s Next?
• Settlement parties signed agreement in
spring 2003
• Ongoing applications of PRDSS:
– Identification/evaluation of candidate lands for
retirement (PVACD and CID)
– FWS B.O. on Pecos Bluntnose Shiner
– Identification, evaluation, and refinement of
alternatives for ongoing Carlsbad Project EIS
– Annual Carlsbad Project water accounting
(Reclamation)
Settlement Model Assumptions
(example)
• Distribution of water from 6,000 acres of CID land purchased by
ISC conditioned on cumulative Compact credit and current water
supply (ISC water “yield” = 1.176 x allotment):
– If CID supply < 50Kaf on March 1, ISC water realloted to CID
– If credit < 50Kaf, deliver ISC water to stateline 5x annually
– if 50Kaf < credit < 115 Kaf, AND current supply > 90Kaf, ISC gets all
water > 90 Kaf, up to 24,696 af (3.5x1.176x6000). Beyond 114,696
af, water is alloted to all 25,055 acres equally.
– if 50Kaf < credit < 115 Kaf, AND current supply < 90Kaf, ISC shall
make its CID water available for re-distribution to CID irrigators up to
3.5 af/acre (90Kaf)
– if credit > 115 Kaf, ISC shall make its CID water available for redistribution to CID irrigators up to decreed limit (3.697 af/acre); IF CID
irrigators have full allotment, excess water to be held over in storage
RiverWare Rulebased Simulation
• Operational
policy is
simulated
using
RiverWare
rules
• Management
alternatives
can be
readily
evaluated
RiverWare - Implementation
• USBR began work in 1991 following FWS B.O.
– Data collection program
– Daily timestep model of river/reservoir operations
– Need to evaluate operational alternatives
• HWG review / enhancement process started 1999
– Evaluation of data and methods (side inflows, routing,
gain/loss, evaporation, bank storage, etc.)
– Development of “Ruleset” representing current reservoir
operations policy
• Relevance to Settlement:
– Impact of reservoir operations and physical processes on
Texas deliveries and CID allotments
– Long-term water supply implications
Roswell Artesian Basin Groundwater
Model - Implementation
• RABGW “roots”: Lewis model (1991-1995);
Keyes and SSPA enhancements
• Calibrated based on 1967-2000 heads,
1967-2000 pumping data, and 67-2000
Pecos River base inflows
• Relevance to NEPA process:
– Interrelationships between surface water
deliveries, well pumping, and climatic drivers
– Direct impact on Pecos River flows from Acme to
Artesia
Carlsbad Area Groundwater Model Implementation
• CAGW “roots”: Lewis model (1991);
Bjorklund and Motts survey (1959)
• Updated and enhanced by NM OSE and
Intera
• Relevance to Settlement:
– Interrelationships between surface water
deliveries, supplemental well pumping, and return
flows
– Direct impact on Pecos River flows below Avalon
(and thus stateline deliveries)
RBAM - Implementation
• Mass-balance calculation of Red Bluff flows
– Input includes RiverWare and CAGW outputs via
DPT
• Monthly and annual surface-water budget for
the Avalon to state-line reach
• Relevance to Settlement:
– Pecos Compact obligations and departures
– Impacts of potential changes in reservoir
operation and CID irrigation supply sources on
stateline deliveries
DPT - Implementation
• Coupling of RiverWare, CAGW, and RBAM
• RiverWare post-processing
– CID diversion, Avalon seepage and Avalon releases
– Time-step conversion
• CAGW pre- and post-processing
– Determination of CID supplemental well pumping
entitlements
– Computation of Pecos River gains below Avalon
• Archiving
– Data
– Policy alternatives