1. Eduardo Garaña , P.E. Director-Water Department October 15, 2003
Lake Corpus Christi/ Choke Canyon Water Rights Permit & Reservoir Operating Plan/Water Use Projections and Current Major Projects
Eduardo Garaña , P.E.
Director-Water Department
October 15, 2003

2. Key Dates/Events
May City of Corpus Christi applied for Choke Canyon Water Rights.
October Texas Water Rights Commission issued Choke Canyon Water Rights Permit with freshwater inflow requirements.
June Choke Canyon Dam construction completed.
May Choke Canyon Water Right Permit adjudicated,
June Choke Canyon filled and spilled the first time.

3. Key Dates/Events (Cont.)
December Letter received by the TNRCC questioning freshwater inflows.
May TNRCC ordered City to begin freshwater inflows to Bays and Estuaries.
March TNRCC Agreed Order amended interim operational procedures and created NEAC.
April TNRCC Agreed Order amends operational procedures and continues NEAC.
April TNRCC Agreed Order amends operational procedures and continues NEAC.

4. Choke Canyon Water Rights Permit # 3358 Special Condition 5 (b):
“Following completion and filling of Choke Canyon Dam and reservoir, scheduled releases shall be made from the reservoir system at Lake Corpus Christi Dam together with return flows to the estuaries for the proper ecological environment and health of related living resources therein. …”

5. Choke Canyon Water Rights Permit # 3358 Special Condition 5 (b)(cont):
“...Water provided to the estuaries from the reservoir system under this paragraph shall be released in such quantities and in accordance with such operational procedures as may be ordered by the Commission. Permittees shall provide not less than 151,000 acre-feet of water per annum for the estuaries by a combination of releases and spills from the reservoir system at the Lake Corpus Christi Dam and return flows to Nueces and Corpus Christi Bays and other receiving estuaries.”

6. Certificate of Adjudication No. 21-3214, 1984 - Special Condition 5.b.
Requires permit holders to provide freshwater inflows to the Nueces Estuary “for the proper ecological environment and health of related living marine resources therein.”
States that freshwater inflows shall:
Be not less than 151,000 acre-feet annually
Begin after Choke Canyon fills for the first time
Be in accordance with operational procedures as ordered by the Commission (now TNRCC)
Be a combination of spills, releases and return flows
Federal 404 Permit includes freshwater inflow requirement.

7. 1992 Agreed Order
Amended the 1990 Reservoir System Operational Procedures by Establishing a Monthly Schedule of Required Inflow Amounts.
97,000 acft/yr. total to Nueces Bay
500 acft/mo. return flow credits
Creates NEAC Whose Mission is to “Consider Such Additional Information and Related Issues and to Formulate Recommendations for the Commission’s Review and Actions.”

8. 1995 Agreed Order
Limits amount of “releases” to amount of reservoir system inflows, up to a monthly estuary inflow target
Targets essentially the same as previous release schedule.
“Pass-through” reservoir inflows up to monthly target.
Reservoir inflows above monthly target are captured & stored.
If reservoir inflows are less than monthly target, only inflow amount is “passed through.”
No requirement to “release” stored water to make up the difference.
Monthly targets reduced when salinity is in desirable range.
Credits for excess pass-through’s in one month carried to next.
Drought contingency provisions drastically reduce targets during low flow periods.

9. 2001 Agreed Order
Diverts Pass-through’s and Other Inflows to Nueces Delta
Nueces River Overflow Channel into Rincon Bayou.
Pipeline from Calallen Pool to Rincon Bayou.
Provides for Automatic Measures and Relief
50%: Increased Public Awareness.
40%: Restrict Time-of-Day Lawn Watering.
(Inflow Targets Reduced to 1,200 af/mo)
30%: Restrict Lawn Watering to No More Than Once Every 5 Days.
(Inflow Targets Suspended)

10. Agreed Order Summary
The City of Corpus Christi, as Operator of the Reservoir System, shall provide not less than 151, 000 ac-ft of water per annum for the estuaries
>70% storage capacity—138,000 ac-ft target
>40% but less than 70%--97,000 ac-ft target
>30% but less than 40%-- 1,200 ac-ft target*
<30%-- Total suspension of Pass-thrus*
* Implementation of Lawn Watering Restrictions

11. Agreed Order Summary (cont.)
Additional Relief Options:
>Flows in excess of monthly targets
>Salinity levels in Upper Nueces Bay
Water Conservation and Drought Contingency Plans for Customers

12. Sources of Nueces River
Basin
Water Supply
AUSTIN
LEAKEY
HOUSTON
DEL
RIO
SAN
ANTONIO
UVALDE
Choke Canyon
Dam
Completed –
1982
Frio
River
Atascosa
River
Frio River Basin
EAGLE
PASS
Nueces
River
Nueces River Basin
Wesley Seale
Dam
Completed –
1958
CORPUS
CHRISTI
LAREDO

13. Current Operating Policy
Revised during drought.
…..in order to provide maximum dependable yield from the two reservoirs, the water level in Lake Corpus Christi will be allowed to drop to elevation 74 feet before water is released from Choke Canyon Reservoir….. When the elevation of Choke Canyon Reservoir drops to 155 feet, Lake Corpus Christi will be lowered to its minimum elevation.

14. Lake Corpus Christi Reservoir Wholesale Water Providers
Beeville
Pipeline
1982
Lake Corpus Christi Reservoir
Wholesale Water Providers
Mathis
Pipeline
1982
Alice
Pipeline
1964

15. Choke Canyon / Lake Corpus Christi Reservoir System Daily Pass-Through Status Report Report Date: May 28, 2002
RESERVOIR STATISTICS

16. Weather Related Information

17. STREAM FLOWS

18. USGS Gauge Locations
NRMT

19. ESTUARY INFLOWS and PASSTHRU REQUIREMENTS (All values are in AcFt)

20. LAKE TEXANA STATISTICS (All values are in AcFt)

21. EFFECT OF CHANGES TO AGREED ORDER

22. WATER UTILIZATION

23. Benefits of Lake Texana Water on Reservoir Storage Since Mary Rhodes Pipeline Startup
100 e 80 g a r o t S
Historical m e 60 t s y S h t n o 40 M f
Without o d
Lake Texana n
(Estimated) E 20 3 4 5 6 7 8 9 1 9 9 9 9 9 9 9 9 9 9 9 9 9 9 1 1 1 1 1 1 1 2 2
Year

25. Background (cont.)
Water provided to the estuaries from the reservoir system under this paragraph shall be released in such quantities and in accordance with such operational procedures as may be ordered by the Commission. Permittees shall provide not less than 151,000 acre-feet of water per annum for the estuaries by a combination of releases and spills from the reservoir system at the Lake Corpus Christi Dam and return flows to Nueces and Corpus Christi Bays and other receiving estuaries.

26. Background (cont.) Construction Completed 1982
Inundation Occurred 1987
Letter of Inquiry Received 1989
Texas Water Commission Took Jurisdiction in Spring 1990
Creation of Technical Advisory Committee
TAC—Characterization Study and Final Report to Hearings Examiner

27. Water Use Projections for Corpus Christi Regional Water System
Salutation
Introduce Panel Members
Demand (Sources and Methodologies)
Supply Definitions and Current Supply
Current Demand and Supply

28. Demand

29. Projection Comparison City and TWDB
Supply
Regional Water Plan
One-period growth rate equation (High-Case)
Linear Regression Method (Low-Case)
These are different ways of estimating use. Difference here is the use of open ended contracts for wholesalers and untreated water customers. Contracts call for their maximum use to be the highest three yr. average + 10 percent.
Regional Plan identified about 10K AF of needs from cities that would not be able to meet the new stricter arsenic standard and could possibly be looking our way to meet that need.
We feel we capture that with our 8 percent planning margin which equals 10K AF
acre-feet

30. Projected and Recent Actual Demand

31. Supply

32. Reservoir System Yield
That amount of water that the reservoir (or reservoir system) could have produced annually if it had been in place during the worst drought of record.
That volume of water you can reliably depend on each year during the worst drought or drought of record.
The Drought of Record is the dry period between times like now when the reservoirs are at full capacity (approximately 84 months).

33. Reservoir System Inflows- Lowest 3 Year Periods
Each drought is getting more severe as measured by the lowest 3 year periods of inflow in each drought
Droughts of the 50’s, 60’s, 80’s, and 90’s.
We live in an area dominated by worsening drought and punctuated by short wet periods.
acre-feet

34. Reservoir System Yield Modeling Assumptions
Safe yield assumption-reservoir is left with a volume of reserve supply (6 months of supply)
Firm yield assumption-reservoir is used till empty
Safe yield assumptions could be 4 month reserve or 12 mo or 10 percent of reservoir capacity.
For the purposes of planning our water resource needs ( a basic necessity) we are applying both a firm yield and safe yield when considering supply in the reservoir system
We can’t assume for planning purposes, that all of the volume in a reservoir is usable, or that we could use all of the reservoir volume till empty.
We don’t think it’s reasonable to assume that during a drought of record the reservoir would be used till empty.
Drought periods are getting more severe over time, this is an area dominated by drought with occasional wet periods.
It becomes a question of quality.
You may not run out completely (and this is true for many natural resources) at some point it becomes too expensive to treat and use.

35. Firm Yield CCR/LCC System (1992 – 2001)
300,000
250,000
Captures the variability of firm yield calculation. It can change due to a number of reasons. For example...
1992 (HDR)
Phase II CCR/LCC System Operations Policy
1992 Interim Order
HDR/TNRCC Hydrology (1934 – 1989)
1995 (HDR)
1995 Agreed Order (the pass through plan)
1997 (HDR)
Phase IV CCR/LCC System Operations Policy lower LCC and less evap and more opportunity to capture
1995 Agreed Order
1998 (HDR)
Phase IV CCR/LCC System Operations Policy
HDR/TNRCC Hydrology (1934 – 1997)
2001 (HDR)
2001 Agreed Order
200,000
System Yield (acft/yr)
150,000
100,000
50,000
1992
1995
1997
1998
2001
Time (Non-Successive Years)

36. } } Total Supply (2003) Firm Yield Safe Yield 237,000 202,932 Texana
Two Bar Graphs Compare differences between FY and SY
Seen on the bottom shaded portions of each.
For FY 183,160
For SY 149,069
The other shaded portions are the same for both cases…
31,400 Firm Texana water purchased and delivered through the Mary Rhodes Pipeline.
10,400 also delivered through MR Pipeline is temporary in that it allows for growth in Jackson County
4,500 acre-feet was recently purchased interruptible water
And our totals supply is shown
under FY 229,500 AF
under SY 195,432 AF
What do each of these look like over time?
Texana
CCR / LCC
CCR / LCC
acre-feet

37. Total Supply Projection (Current Sources)
These are the two different levels seen on the previous graph
The decrease over time due to sedimentation of the reservoirs.
acre-feet

38. Demand and Supply acre-feet
Finally we examined where demand overcomes supply
It depends on whether you’re looking at a firm yield assumption or a more realistic safe yield assumption.
When we compare the Demands using the 1PGR and LR to the Firm Yield Result:
Demand overcomes supply as early as 2036
Demand overcomes supply as late as 2048
Under Safe Yield Methodology
Demand overcomes supply as early as 2025
Demand overcomes supply as late as 2030
We end up with this polygon or quadrangle or quadrilateral shaped area that represent our worst and best case water resource scenarios.
acre-feet

39. Projected and Actual Combined Demand and Supply

40. Demand and Supply

41. Summary Demand = Supply
2028
Safe Yield/ Higher Demand
2034
Safe Yield/ Lower Demand
2038
Firm Yield/ Higher Demand
2052
Firm Yield/ Lower Demand
Slide
Increased future economic opportunity is only one cost of not meeting your needs.
The costs of not meeting your needs are tremendous.
The costs of not meeting a city’s water resource needs far outweigh the capital costs to meet needs.

42. Future Actions Continue to use multiple projection methodologies
Compare city’s projections to TWDB’s and other available projections
Continue to update projections on a one-year planning cycle
Optimize existing water supply sources
Continue to develop future water supply sources
Slide
Increased future economic opportunity is only one cost of not meeting your needs.
The costs of not meeting your needs are tremendous.
The costs of not meeting a city’s water resource needs far outweigh the capital costs to meet needs.

43. City of Corpus Christi Desalination Initiatives

44. Padre Island Desalination Project

45. Preferred Facility Siting
Preferred RO Facility:
Padre Island Pump Station / Nueces County Packery Channel Park
Alternate RO Facility Location:
At NCWCID4 Pumping Station
Alternate ASR Well Location:
Mid-Mustang Island
Preferred Source Well Location:
City-Leased TGLO Land at Packery Channel
Preferred ASR Well Location:
Near Nueces County Padre Balli Park along South Padre Island Drive

46. Recommended Project 3.0-mgd project includes:
Chicot Aquifer Horizontal Directionally-Drilled well field
1.0-mgd RO facility
(with buildings and infrastructure to support 5-mgd)
2.0-mgd ASR capacity
By-Product Disposal via Deep Well Injection
(with sufficient capacity to handle 5.0 mgd)
Site work and transmission piping
Upgrades to existing Padre Island Pumping Station
Estimated cost: $23.2 million including contingencies (June dollars,  30 percent)
Subject to verification/refinement based on results of hydrogeologic and water quality testing program

47. State Desalination Initiative

48. Why Coastal Bend? Why Corpus Christi?
Largest Gulf-front City with a Strategic Port in Texas
Largest Industrial City in Attainment Status for Air Quality
Progressive and History of Long-range Water Planning
Mary Rhodes Pipeline
Water demands met through 2050
Regional Water System
Proximity to Users
Local and Regional Support

49. City of Corpus Christi Regional Water System
City of Corpus Christi and Coastal Bend
Serves 75% of M&I Demand for Region N
Supply Water to Suppliers in Seven Counties
Existing Municipal Customers
Existing Industrial Customers
Koch/Flint Hills, Citgo, Valero, Coastal, Equistar
Power Generation
Potential to Supply Future Customers

50. Corpus Christi and Regional Water System

51. Texas Coastal Bend Project Description
25 mgd seawater desalination facility
Located at Barney Davis Power Plant
Deliver potable water to Corpus Christi Regional Water System
Ability to Expand
Existing Marine R&D facilities
Hart Foundation
A&M
UTMSI

52. Barney Davis Plant Site and Corpus Christi Distribution System
A&M /UTMSI Existng
Marine Research Facilities
A&M /UTMSI Existing
Marine Research Facilities
Oso Bay

53. Barney Davis Intake Outfall 1.5 mile Pipeline

54. COE Nueces River Basin Feasibility Study

55. US Army Corps of Engineers Reconnaissance Study of the Nueces Basin Watershed
Federal funds are available through Corps of Engineers (COE) for projects which include “Ecosystem Restoration” or “Flood Damage Reduction”
Federal funds can pay for up to 50% of study cost and 65% of construction costs
Projects can include water supply

56. Important Ecosystems Dependant on Nueces River System
Hill Country Streams and Associated Springs
Nueces Delta and Estuary 15

57. US Army Corps of Engineers Reconnaissance Study Identified 10 Projects
Flooding downstream of Lake Corpus Christi and throughout the Nueces Basin
Recharge enhancement
Cotulla diversion projects to enhance storage in LCC/CCR system
Two-way pipe project to enhance storage in LCC/CCR system
Desalination
Treated effluent placement in Nueces Delta
Water quality in Choke Canyon reservoir
Stream restoration in the upper Nueces Basin
Brush management
Exotic aquatic plant removal

58. Projects Selected to Move Forward to Feasibility Phase
Desalination -Locally and regionally supported concept. Originally studied in the Coastal Bend Regional Water Plan is sited next to an existing power plant to minimize power costs and reduce treatment costs utilizing heat from the plant. Also combines brackish groundwater with seawater to reduce concentration of TDS in brine, through existing plant discharge facilities.
Cotulla diversion -Water quality enhancement, water supply and possible flood damage reduction project bypasses high channel losses in the braided reach and increases storage capacity.
Two-way pipeline -Conveys releases over 33cfs with very little losses, creates opportunity for more freshwater inflow by increasing reservoir storage. Higher lake levels improve water quality. Development of off-channel storage site with a pump station would provide flood control benefits to the Nueces delta and could increase firm yield to regional suppliers with less evaporation loss.
Wastewater diversions -Take treated effluent from one or more of the City’s municipal wastewater treatment plants and discharges it into critical areas of the delta to help restore the balance of freshwater and nutrients, studies show a potential increase in biological productivity of 3 to 5 times.
Recharge enhancement projects -Would contribute significantly to the spring flow, reduce the possibility of the springs going dry, protecting the ecosystem. Would require mitigation to the City. A portion would be used for water supply.
Brush control -would use plowing, grubbing and dozing as well as herbicides and controlled burns to control the dominance of trees and brush, resulting in increased stream flow and aquifer recharge.
Desalination project at Barney Davis
Cotulla diversion to enhance Choke Canyon storage
Two-way pipe project between CCR and LCC to minimize channel losses
Additional wastewater diversions to Nueces River Delta
Recharge enhancement projects with appropriate mitigation for City
Brush control

59. Study Participants Co-sponsors Army Corps of Engineers
City of Corpus Christi
San Antonio Water System (SAWS)
San Antonio River Authority (SARA)
Guadalupe Blanco River Authority (GBRA)
Nueces River Authority (NRA)
Other Interested Parties
Edwards Aquifer Authority (EAA)
Region N Water Planning Group (Region N)

60. City Permitting Requirements, Time and Effort Planned
Padre Island Desalination
Permits for hydro-geologic borings and permit validation studies
Allowance of $1M, 100 percent City Expense
Two Desalination Projects at Barney Davis
Expected to benefit from TWDB’s RW Beck Report
South-most Brackish, Freeport, Padre Island Experience will be used

61. Permitting Requirements City Time and Effort Planned Cont.
Additional Wastewater Diversions to the Nueces Delta
City has expended extensive time and resources to investigate and establish baseline information for use in possible expansion wastewater diversion projects.

62. Questions?