January 19, 2005

1
Agenda Item 9.7Presentation of Results of
Including BRA System Operations into the Brazos G
WAM Model

• January 19, 2005

2
Objectives

• Incorporate BRA System Modeling strategies into
  the Brazos G WAM
• Determine water availability from the BRA System
  to meet specific WUG needs
• Analyze the effects of the additional
  appropriation under BRA System Operations on
  water management strategies in the 2006 plan

3
Objectives

• Incorporate BRA System Modeling strategies into
  the Brazos G WAM
• Determine water availability from the BRA System
  to meet specific WUG needs
• Analyze the effects of the additional
  appropriation under BRA System Operations on
  water management strategies in the 2006 plan

Task Completed
Task In-Progress
Task Completed
4
WUG Analysis Tasks Accomplished

• Identified WUGs with needs located in counties
  adjacent to Brazos River
• Grouped these WUGs by geographic proximity (10)
• Added demands into the Brazos G WAM to analyze
  the potential supply from the BRA System
  Operations
• Determined amount of BRA water available to meet
  WUG needs at BRA System Rate

5
WUG Analysis On Going

• Include Lake Granger supply augmented with
  interruptible and Carrizo-Wilcox Aquifer to
  supply Williamson County needs.
• Estimate the facilities and operational costs
  associated with using the BRA water to meet these
  needs.
• Compare cost of utilizing BRA system water with
  other potential WMS.

6
Brazos G WAM

• Year 2060 reservoir sedimentation conditions
• Brazos G Year 2060 estimated return flows
• BRA contracts placed at actual diversion
  locations
• 761,551 acft of authorized diversions
• 600,946 acft of contractual commitments included
• Brazos G WAM with BRA System Operations
• BRA reservoir system operated to meet additional
  BRA appropriations at main stem locations
• 395,000 acft of water available at lower basin
  diversion point
• 995,946 acft total amount of water potentially
  available from existing rights and additional
  lower basin diversion

7
Water Management Strategy Analysis

• Evaluate WMS with the BRA System Operations in
  place.
• Millican-Bundic
• Breckenridge (Cedar Ridge)
• Groesbeck
• Millers Creek
• Little River Off-Channel
• South Bend
• Turkey Peak
• Double Mountain Fork East Site
• Little River On-Channel Reservoir

8
Water Management Strategy Analysis

• Evaluate the effect of incorporating WMS into the
  BRA System.
• Millican-Bundic
• Breckenridge (Cedar Ridge)
• Turkey Peak
• Little River Off-Channel
• Little River On-Channel
• South Bend
• Evaluate the effect of incorporating existing
  water supply projects into the BRA System
• Lake Waco
• Lake Granger supplemented with Carrizo-Wilcox
  Aquifer

9
Double Mountain Fork Yield Summary
10
Double Mountain Fork WMS Analysis
11
Cedar Ridge Yield Summary
12
Cedar Ridge WMS Analysis
13
South Bend Yield Summary
14
South Bend WMS Analysis
15
System Operations An Explanation
Yield at the Reservoir B
Yield at the Reservoir A
Intervening Flow
Reservoir Releases
Reservoir Releases
Intervening Flow
Diversion
Yield at downstream diversion location is A B
InterveningX
16
System Operations An Explanation
Drought Period
Time
17
Turkey Peak Yield Summary
18
Turkey Peak WMS Analysis
19
Little River O/C Yield Summary
20
Little River Off-Channel WMS Analysis
21
Little River On ChannelYield Summary
22
Little River On-Channel WMS Analysis
23
Millican-Bundic Yield Summary
24
Millican-Bundic WMS Analysis
25
Existing Project Analysis Lake Waco

• Modeling Assumptions
• Keep a specified demand lakeside
• 2060 demands plus 15
• 67,935 acft of lakeside demand
• Limit the amount of storage that can be used to
  supplement the system diversion
• Lake level target of 455 feet
• 134,796 acft (71) storage in reserve for local
  uses
• Results
• With above assumptions
• Adds 6,000 acft to yield of BRA Sys-Ops

26
WMS Analysis What is the big picture?

• From a basin-wide perspective
• As a stand-alone project
• As part of the BRA Sys-Ops

27
WMS Analysis Cedar Ridge
Existing BRA Supply Plus System Yield
Existing BRA Supply
28
WMS Analysis Little River O/C
Existing BRA Supply Plus System Yield
Existing BRA Supply
29
WMS Analysis Millican-Bundic
Existing BRA Supply Plus System Yield
Existing BRA Supply
30
WMS Analysis 3 Projects Combined
Existing BRA Supply Plus System Yield
Existing BRA Supply
31
Conclusion

• In summary
• The BRA Sys-Ops does reduce water available from
  some potential WMS.
• Potential WMS can increase overall supply when
  operated within the BRA System.
• Operation of existing water supply projects
  within the BRA system is constrained by local
  needs.

32
Discussion QA

• HDR recommendation
• Continue evaluation of specific WMS that would
  use BRA System water as a source of supply.
• Consider specific WMS be included in 2006 Plan
  as components of BRA System
• Little River Off-Channel Reservoir
• Millican-Bundic Reservoir
• Continue evaluation of Lake Granger /
  interruptible WMS to supply Williamson County