South Central Texas Regional Water Plan
Executive Summary
Background
Since 1957, the Texas Water Development Board (TWDB) has been charged with preparing a comprehensive and flexible long-term plan for the development, conservation, and management of the state’s water resources. The last water plan developed at the state level, Water for Texas, August 1997, was produced by the TWDB in cooperation with the Texas Parks and Wildlife Department (TPWD), Texas Natural Resource Conservation Commission (TNRCC), and a number of stakeholder groups. Future State Water Plans, including the one due January 5, 2002, will be based on approved regional water plans pursuant to requirements of Senate Bill 1 (SB1), enacted in 1997 by the 75th Legislature. As stated in SB1, the purpose of the regional planning effort is to:
“Provide for the orderly development, management, and conservation of water resources and preparation for and response to drought conditions in order that sufficient water will be available at a reasonable cost to ensure public health, safety, and welfare; further economic development; and protect the agricultural and natural resources of that particular region.”
SB1 also provides that future regulatory and financing decisions of the TNRCC and the TWDB be consistent with approved regional plans.
The TWDB divided the state into 16 planning regions and appointed members to the regional planning groups. The South Central Texas Regional Water Planning Group (SCTRWPG) has 20 members appointed by the TWDB and one member added by the SCTRWPG. The members represent 11 interests or stakeholders (Public, Counties, Municipalities, Industries, Agricultural, Environmental, Small Businesses, Electric Generating Utilities, River Authorities, Water Districts, and Water Utilities), serve without pay, and are responsible for the development of the South Central Texas Regional Water Plan (Table ES-1).
Table ES-1.
South Central Texas Regional Water Planning Group Members
|
Name |
Interest |
Entity |
County |
|
Evelyn Bonavita |
Public |
League of Women Voters |
Bexar plus 3 others |
|
Charles Johnson, Judge |
Counties |
Dimmit County |
Dimmit |
|
John Kight, Commissioner |
Counties |
Kendall County |
Kendall |
|
Mike Thuss, President |
Municipalities |
San Antonio Water System |
Bexar |
|
Gary Middleton, Mayor |
Municipalities |
City of Victoria |
Victoria |
|
Pedro Nieto |
Municipalities |
City of Uvalde |
Uvalde |
|
Hugh Charlton |
Industry |
Du Pont |
Victoria |
|
Richard Eppright |
Agriculture |
Graham Land & Cattle Co. |
Gonzales & Atascosa |
|
Bruce T. Foster |
Agriculture |
Texas Farm Bureau |
Medina |
|
Susan Hughes |
Environment |
Audubon Society |
Bexar |
|
Douglas R. Miller |
Small Business |
Wittig & Miller |
Comal & Guadalupe |
|
Gloria Rivera |
Small Business |
Electrical Engineer |
Guadalupe |
|
Darrell Brownlow |
Small Business |
Environmental Consultant |
Wilson |
|
Mike Fields |
Elec.Gen.Utilities |
CP&L Coleto Plant |
Goliad |
|
Bill West |
River Authorities |
Guadalupe-Blanco RA |
Guadalupe plus 9 others |
|
Fred Pfeiffer |
River Authorities |
San Antonio RA |
Bexar plus 3 others |
|
Greg Ellis |
Water Districts |
Edwards Aquifer Authority |
Bexar plus 6 others |
|
Mike Mahoney |
Water Districts |
Evergreen UWCD |
Atascosa plus 3 others |
|
Tom Moreno |
Water Districts |
Bexar Metropolitan WD |
Bexar |
|
Ron Naumann |
Water Utilities |
Springs Hill WSC |
Guadalupe |
|
Con Mims |
Added by RWPG |
Nueces River Authority |
Nueces River Basin |
The SCTRWPG adopted bylaws to govern its operations and, in accordance with its bylaws, selected the San Antonio River Authority (SARA) to serve as its administrative agency (Qualified Political Subdivision) to: 1) Develop a scope of work; 2) Apply for a TWDB planning grant; 3) Contract with the TWDB for the grant; and 4) Manage the development of the Regional Water Plan, including supervision of consultants. Members of the SCTRWPG and key staff of several participants serve as an ad hoc staff workgroup to review and guide SARA and its consultants’ work.
Pursuant to TWDB Rules for Regional Water Planning Grants, Regional Water Planning Guidelines, and State Water Planning Guidelines (31 Texas Administrative Code, Chapters 357.7 and 357.9), the SCTRWPG developed a scope of work, schedule, and budget to prepare a water plan for the South Central Texas Region, which includes the counties shown in Figure ES-1.
Figure ES-1. South Central Texas Planning Region (Region L)
The development of the Regional Water Plan was organized into three phases. Phase 1 included preparation of a description of the planning region, population and water demand projections, quantification of current supplies, comparison of water demands and supplies to determine water needs (shortages) and surpluses, and identification of feasible water supply options or management strategies. Phase 2 included formulation and evaluation of alternative regional water plans. Phase 3 involved preparation of the Regional Water Plan, consideration of identification of unique ecological stream segments and reservoir sites, and regulatory, administrative, and legislative recommendations. The South Central Texas Regional Water Plan is presented in three volumes, with structure and contents as shown in Figure ES-2.
Figure ES-2. Plan Structure
Description of South Central Texas Region
The South Central Texas Region includes counties that are located in whole or in part in the Rio Grande, Nueces, San Antonio, Guadalupe, Colorado, and Lavaca River Basins, and the Colorado-Lavaca, Lavaca-Guadalupe, and San Antonio-Nueces Coastal Basins. The physical terrain of the region ranges from the Hill Country of the Edwards Plateau to the Coastal Plains. A general description of the region, including climate, land, water, vegetation, wildlife, population, economy, and water agencies is presented below.
Climate: The South Central Texas Region lies in three climatic divisions in Texas: the Edwards Plateau division, the South Central division, and the Upper Coast division. Mean annual temperature ranges from about 70 degrees Fahrenheit in the east to about 80 degrees in the central parts of the region. Summers are usually hot (above 90 degrees F) and humid, while winters are often mild and dry. There is little variation in the day-to-day summer weather except for the occasional thunderstorm, which produces much of the annual precipitation within the region. The cool season begins about the first of November and extends through March. Winters are ordinarily short and mild, with most of the precipitation falling as drizzle or light rain.
Mean annual precipitation in the region ranges from a high of 38 inches per year in DeWitt County, in the eastern part of the region, to a low of 23 inches per year in the Nueces River Basin, in the west. The South Central Texas Region is subject to the threat of hurricanes each year from mid-June through the end of October. Records dating back to 1871 show that, on average, a tropical storm or hurricane has affected the region once every 3 years.
Land: The majority of the South Central Texas Region is underlain by Cretaceous Age limestone, which forms the Edwards Plateau. East and south of the Plateau are Upper Cretaceous chalk, limestone, dolomite, and clay. The Balcones Fault Zone System forms the boundary between the Edwards Plateau and the Gulf Coastal Region. A Tertiary Age sequence of southeasterly dipping sand, silts, clay, glauconite, volcanic ash, and lignite overlie the Cretaceous Age strata. A sequence of clay, sand, caliche, and conglomerate of the Pliocene Age Goliad Formation underlie the coastal areas of the region. Overlying the Goliad Formation is the Quaternary Age Lissie Formation. The Beaumont Formation overlies the Lissie Formation, and throughout the region, alluvial sediments occur along streams and coastal areas.
Of the 12.82 million acres of land area in the planning region, over 10.35 million acres (81 percent) are farmland and ranchland, with 2.68 million acres classified as cropland, of which about 1.15 million acres were harvested in 1997. Approximately one-tenth (252,616 acres) of cropland in the region was irrigated in 1997. The leading irrigation counties are Uvalde, Frio, Medina, Atascosa, and Zavala. In 1997, there were 20,098 farms and ranches in the region with an average size of 866 acres.
Water: The South Central Texas Region includes parts of six major river basins (Rio Grande, Nueces, San Antonio, Guadalupe, Lavaca, and Lower Colorado) and overlies the Edwards and Gulf Coast Aquifers and southern parts of the Trinity, Carrizo, and Edwards-Trinity (Plateau) Aquifers. In addition to these water resources, the area also overlies two minor aquifers (Queen City and Sparta).
Comal and San Marcos Springs are significant water resources in the region. San Marcos Springs has the greatest flow dependability and environmental stability of any spring system in the southwestern United States. Comal Springs, located in New Braunfels, serves as the source for the Comal River, a tributary of the Guadalupe River. Unlike San Marcos Springs, Comal Springs is more responsive to drought conditions and ceased flowing in June of 1956 as a result of severe drought.
Vegetation: The South Central Texas Region contains a vegetation transition from the lowland forests of the southeastern United States to the arid grasslands of the western uplands and tropical thorn scrub to the south. The vegetation consists of dendritic networks of wooded stream corridors of eastern species that dissect upland grasslands and savannahs that harbor western species. The vegetational areas of the Region are the Edwards Plateau, South Texas Plains, Blackland Prairies, Gulf Prairies and Marshes, and the Post Oak Savannah.
The Edwards Plateau area includes all of Kendall County; the northern portions of Uvalde, Medina, Bexar, and Comal Counties; and that portion of Hays County located within the planning area. This area is characterized by springfed, perennially flowing streams that originate in its interior and flow across the Balcones Escarpment. This area is predominantly rangeland, with cultivation confined to the deeper soils.
The South Texas Plains area lies south of San Antonio and includes all or parts of Uvalde, Zavala, Dimmit, Medina, Frio, LaSalle, Bexar, Atascosa, Wilson, Karnes, DeWitt, and Goliad Counties. This vegetational area is characterized by subtropical dryland vegetation consisting of small trees, shrubs, cactus, weeds, and grasses. Principal plants are honey mesquite, live oak, post oak, several members of the cactus family, blackbrush acacia, guajillo, huisache, and others that often grow very densely. Long-continued grazing has contributed to the dense cover of brush. Most of the desirable grasses have persisted under the protection of brush and cacti.
The Blackland Prairies area includes parts of Bexar, Comal, Guadalupe, Hays, Caldwell, Gonzales, and DeWitt Counties. The area has timber along the streams, including a variety of oaks, pecan, cedar elm, and mesquite. In its native state, it was largely a grassy plain, but most of this fertile area has been cultivated, and only small acreages of meadowland remain in original vegetation.
The Gulf Prairies and Marshes vegetational area includes all or parts of Victoria, Goliad, Refugio, and Calhoun Counties. There are two subunits: (1) the marsh and salt grasses immediately at tidewater and (2) a little farther inland, a strip of bluestems and tall grasses, with some gramas in the western part. Many of these grasses make excellent grazing. Oaks, elm, and other hardwoods grow to some extent, especially along streams, and the area has some post oak and brushy extensions along its borders. Much of the Gulf Prairies is fertile farmland.
The Post Oak Savannah is a secondary forest region and includes all or parts of Guadalupe, Caldwell, Wilson, Gonzales, DeWitt, Goliad, and Victoria Counties. It is immediately west of the primary forest region, with less annual rainfall and a little higher elevation. Principal trees are post oak, blackjack oak, and cedar elm. Pecans, walnuts, and other kinds of water-demanding trees grow along streams. The southwestern extension of this belt is often poorly defined, with large areas of prairie.
Wildlife: Wildlife of the area include white-tailed deer, raccoons, ringtails, gray foxes, coyotes, beaver, bobcats, and several species of skunks. Wintering songbirds such as robins and cedar waxwings may also be found. Virtually all wildlife habitat in the South Central Texas Region is on privately-owned land.
There are approximately 123 species observed within the planning region that are listed by the U.S. Fish and Wildlife Service (USFWS) or TPWD as threatened or endangered. These species are listed by county in Appendix D (Volume III) with notations concerning their habitat preferences and protected status if any. Vertebrates and macroinvertebrates have been found at depths ranging from 190 to 2,000 feet in the artesian parts of the Edwards Aquifer, and Edwards springs support several endangered species.
Population: The South Central Texas Region population has increased from 806,770 in 1950 to approximately 1,954,100 in 1998, an increase of 1,147,300, or 2.4 times. Between 1950 and 1998, 16 counties had a positive growth rate, while five counties (DeWitt, Gonzales, Karnes, LaSalle, and Refugio) lost population. Based on annual growth rates from 1950 through 1998, the fastest growing counties in the region have been Hays (3.34 percent), Comal (3.15 percent), Kendall (2.83 percent), and Guadalupe (2.31 percent). There are 81 cities in the region for which the TWDB has made population and water demand projections. Of the 81 cities, 22 have a population greater than 5,000. Bexar County contains six cities having a population of 5,000 or more, including San Antonio. Four counties, Goliad, Karnes, Kendall, and Refugio, do not have a city of 5,000 or greater.
In 1990, 82 percent of the region’s population resided in urban areas. Age distribution across the region is characterized by a relatively young population. The two age groups that include the highest percentage of the population are under 18 years of age (29 percent) and from 25 to 39 years of age (25 percent). The age groups with the lowest percentage of the population are ages 18 to 24 (11 percent) and ages 65 and older (11 percent).
With respect to education, of those residents in the region who
are 25 years of age are older, 60.7 percent have at least a high
school diploma. The two largest groups
ranked by educational achievement are those who have an 8th grade
education or lower (24.7 percent) and those who have completed high
school, but have not gone to college (27.3 percent). Only 4 percent of the population who
are 25 years or older have a graduate degree.
Economy: The South Central Texas Region economy is based upon crop production, livestock production, mining, manufacturing, and trades and services. All sectors of the economy have experienced solid growth in recent years, with the exception of the mining sector. Employment in the regional economy is heavily supported by a strong trades and services sector, which accounts for approximately 76 percent of the region’s value of output, and a thriving tourism industry in the Hill Country and San Antonio. Fabricated metal products, industrial machinery, and food processing form the core of the region’s manufacturing sector, which accounts for approximately 21 percent of the value of output of the region.
Beef cattle, corn, and grain sorghum are the dominant agricultural enterprises, although vegetables produced in the Winter Garden area add diversity to the region’s agricultural sector. According to the 1997 Census of Agriculture, all crops grown in the South Central Texas Region had a market value of over $290 million in 1997. The leading agricultural producing counties in the region are Bexar, Frio, Uvalde, Medina, and Atascosa.
Livestock marketed in the South Central Texas Region had a market value in 1997 of over $645 million, or about 2.2 times the value of crop production. Major types of livestock are cattle and calves, beef cattle, and sheep and lambs. Layers, pullets, and broilers also contribute significantly to the region’s livestock production, with Gonzales County producing over 98.7 percent of these types of livestock. In 1997, the region’s leading livestock producing counties by market value were Gonzales, Uvalde, Medina, and Wilson.
Mining includes sand and gravel quarries and petroleum products, including oil, natural gas, and lignite. Much of the stone quarried is used in the production of cement in Bexar and Hays Counties. In 1992, these products had a market value of over $42 million.
All but two counties (Comal and Hays) had oil and gas production in 1998. The leading oil and gas producing counties in the region are Refugio, Goliad, Victoria, Atascosa, and DeWitt. In 1998, oil and gas production generated over $290 million in value of products.
The leading types of manufacturing plants in the region are printing and publishing; food and kindred products; petrochemicals; industrial machinery and equipment; and stone, clay, and glass products. In 1992, manufacturing contributed over $9 billion in sales and provided 56,460 jobs in the region, with sales of manufactured goods accounting for 21.3 percent of the total market value of all products produced in the region. The leading manufacturing counties are Bexar, Calhoun, Victoria, and Guadalupe.
In 1992, wholesale trade, retail trade, and services contributed over $32 billion in sales and provided 285,293 jobs in the South Central Texas Region, with trades and services sales accounting for 76 percent of the total market value of all products produced in the region. Wholesale trade accounted for 42.5 percent of the total sales or receipts and provided 11.2 percent of the jobs within the trades and services classification in 1992. The leading counties in wholesale trade were Bexar, Victoria, Guadalupe, and Comal.
Retail trade accounted for 37.1 percent of the total sales and provided 43.1 percent of the jobs within the trades and services classification in 1992. The leading counties in retail trade were Bexar, Victoria, Comal, and Hays.
Services
accounted for 20.4 percent of the total sales and provided
45.7 percent of the jobs within the trades and services classification in
1992. The leading types of services
within the South Central Texas Region are health services, business services,
engineering and management services, and membership organizations.
Water Agencies and Programs: State agencies and programs affecting the South Central Texas Planning Region include the TWDB’s planning, financing, and water information programs; the TNRCC’s water rights administration, waste discharge regulatory functions, dam safety, safe drinking water regulations, weather modification program, and air quality protection programs; the TPWD’s fish and wildlife regulatory and habitat protection programs; and the Texas State Soil and Water Conservation Board’s soil and water conservation efforts, brush control, farm and ranch conservation planning, and cooperative small watershed flood protection programs. Other state agencies, including the Texas A&M University research, education, and extension programs and the Texas Department of Agriculture’s outreach and financing programs, are also relevant to water planning for the region.
Federal programs and agencies that contribute to water supply and water quality protection through both regulation and resources include the U.S. Environmental Protection Agency, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation, USFWS, and U.S. Natural Resource Conservation Service.
In addition to state and federal agencies mentioned above, there are three river authorities and five groundwater conservation districts within the region that have one or more of the following functions: water supply, flood protection, water quality protection, and water management and regulation.
Local Water Plans: In January 1999, the SCTRWPG requested that representatives of each city and water conservation district of the region forward a copy of any available water plans or water management documents. Entities were asked to indicate where they are planning to obtain their water for the next 50 years, including whether or not they had a supply of water for the next 50 years. Approximately 93 responses were received. These responses included copies of plans, as well as summaries of local and regional water plans and planning studies. Of the total number of responses received, 12 were water supply plans for various lengths of time into the future, but none were to 2050, six were Water Conservation District Management Plans, 30 were Emergency Demand Management and Drought Contingency Plans, and the remaining 45 were letters explaining that no specific planning document or report exists, but that the entity has adequate supplies for the future or is in the process of considering its situation.
Population and Water Demand Projections
Population Projections: In order to develop water plans to meet future water needs, it is necessary to make projections of future water demands for the region. TWDB population and water demand projections of the 1996 State Water Plan for cities, rural areas, and water user groups for each of the 21 counties of the region were forwarded to local officials for review. In response to requests by these reviewers, the projections were modified for five counties (Atascosa, Caldwell, Hays, Kendall, and Wilson) and 10 cities (Boerne, Fair Oaks Ranch, Garden Ridge, Lockhart, Luling, Pleasanton, San Marcos, Schertz, Seguin, and Yoakum).
The 1996 estimates published by the U.S. Bureau of the Census indicate that Texas currently ranks as the second most populated state in the nation, with a population of more than 18.3 million. The population of the South Central Texas Region was estimated at 2.0 million in 1996 and is projected to grow at a 1.5 percent compound annual growth rate to 4.5 million in 2050. Of this total, three-fourths are projected to reside in the San Antonio River Basin. Water needs assessments were made for each of the 83 individual cities and 48 rural areas of each county and part of county of each river basin area of the region.
Water Demand Projections: For purposes of water planning, the SCTRWPG adopted advanced conservation water demand projections provided by the TWDB from the 1996 State Water Plan, as specified by SB1. The South Central Texas Region is the only planning region in the state to adopt the advanced conservation projections. Projections were included for each water user group—municipal, industrial, steam-electric power generation, irrigation, mining, and livestock. The projections were at the level of detail of each city, rural area, and county or part of county of each river basin. Projections were also provided at the county and river basin area level of detail for industry, steam-electric power generation, irrigation, mining, and livestock. The projections are summarized below.
Municipal water is fresh water used for drinking, sanitation, and other purposes in homes and commercial establishments of both cities and rural areas. Total municipal water use in the South Central Texas Region in 1990 was 318,495 acft/yr and is projected to increase to 769,523 acft/yr by 2050 (Figure ES-3). Industrial water is fresh water used in the manufacture of industrial products. All industries in the region used 67,016 acft of water in 1990 and are projected to have a demand of 202,379 acft/yr in 2050 (Figure ES-3).
Figure ES-3. Projected Water Demands
Eight counties (Atascosa, Bexar, Calhoun, Frio, Goliad, Guadalupe, Hays, and Victoria) of the region use cooling and boiler feed water in steam-electric power production. In 1990, 43,451 acft of water were used, and it is estimated that by the year 2050, 125,660 acft/yr of water will be needed for the production of steam-electric power (Figure ES-3). In the South Central Texas Region, the principal uses of water for mining are for the extraction of stone, clay, and petroleum and for sand and gravel washing. In the region, total mining water use was 7,799 acft in 1990 and is projected to increase to 14,308 acft/yr in 2050, an increase of over 80 percent (Figure ES-3).
The TWDB irrigation
water use data show annual use for irrigation to grow cotton, grain,
vegetables, and tree crops in the South Central Texas Region in 1990 of
669,440 acft/yr,
or 6.7 percent of the total irrigation water used in Texas in 1990. Projected irrigation
water demands in the Region in 2050 are 516,348 acft/yr, or
22.9 percent less than in 1990 (Figure ES-3). The projected decline is based upon
increased irrigation efficiency, economic factors, and reduced government
programs affecting the profitability of irrigated agriculture. In 1990, water use in the region for
livestock purposes was estimated at 24,400 acft/yr. The TWDB projections for livestock use in the
region in the year 2020 through 2050 are 28,521 acft/yr.
Projected total water demand for the South Central Texas Region is the sum of water demand projections for municipal, industrial, steam-electric power generation, mining, irrigation, and livestock uses. Projected percentage changes in the composition of total water demand by use category from 1990 to 2050 are shown in Figure ES-4.
Major Water Providers: The SCTRWPG identified six Major Water Providers in the South Central Texas Region. These Major Providers are listed in Table ES-2, along with a general description of their service areas. TWDB guidance defines a Major Provider as a provider such as a river authority, water supply corporation, or city that provides a major amount of water to other cities. A plan for each Major Provider is included in the Regional Water Plan.
South Central Texas Region Water Supply: There are five major and two minor aquifers supplying water to the region. The five major aquifers are the Edwards-Balcones Fault Zone, Carrizo-Wilcox, Trinity, Gulf Coast, and Edwards-Trinity (Plateau) Aquifers. The two minor aquifers are the Sparta and Queen City Aquifers. The Region is located in parts of the Rio Grande, Nueces, San Antonio, Guadalupe, Colorado, and Lavaca River Basins and parts of the Colorado-Lavaca, Lavaca-Guadalupe, and San Antonio-Nueces Coastal Basins. The existing surface water supplies of the region include storage reservoirs and run-of-river water rights.
The total quantity of water obtained from aquifers of the region and used within the region in 1990 was 967,327 acft. Of this total, 53.7 percent was from the Edwards Aquifer, 28.8 percent was from the Carrizo, 9.3 percent was from the Gulf Coast, 4.8 percent was from the Sparta, and the remaining 3.4 percent was from the Queen City, Trinity, and Edwards-Trinity (Plateau) Aquifers.
Projected future groundwater supplies available in the South
Central Texas Region during the drought of record are 812,868 acft/yr in
2000, 812,868 acft/yr in 2020, and 675,187 acft/yr in 2050. Supplies available from the Sparta, Queen
City, Trinity, Gulf Coast, and Edwards-Trinity (Plateau) Aquifers are projected
to hold steady on an annual basis throughout the 2000 through 2050 projections
period. However, these aquifers are
projected to supply only about 25 percent of the total groundwater
available to the region in 2050. The
supply available from the Carrizo Aquifer is projected to decline from
304,484 acft/yr for the
Figure ES-4. Distribution of Total Demand Among Users
Table ES-2.
Major Water Providers and Service Areas
|
Major Water Provider |
Service Areas |
|
San Antonio Water System (SAWS) |
City of San Antonio and Bexar County |
|
Bexar Metropolitan Water District (BMWD) |
Bexar, Atascosa, Comal, and Guadalupe Counties |
|
Canyon Regional Water Authority (CRWA) |
Bexar, Caldwell, Comal, Guadalupe, and Hays Counties |
|
Guadalupe-Blanco River Authority (GBRA) |
Kendall, Comal, Hays, Caldwell, Guadalupe, Gonzales, DeWitt, Victoria, Refugio, and Calhoun Counties |
|
New Braunfels Utilities (NBU) |
City of New Braunfels, Comal, and Guadalupe Counties |
|
City of San Marcos |
City of San Marcos, Hays, and Caldwell Counties |
2000 through 2020 period to 168,159 acft/yr for the period after 2020[1]. In the case of the Edwards Aquifer, SB 1477 limits pumpage withdrawals to 450,000 acft/yr until December 31, 2007, and to 400,000 acft/yr beginning in 2008.[2] In addition, SB 1477 states in Section 1.14(h): “… the authority, through a program, shall implement and enforce water management practices, procedures, and methods to ensure that, not later than December 31, 2012, the continuous minimum springflows of the Comal Springs and the San Marcos Springs are maintained to protect endangered and threatened species to the extent required by federal law. The authority from time to time as appropriate may revise the practices, procedures, and methods. To meet this requirement, the authority shall require: (1) phased reductions in the amount of water that may be used or withdrawn by existing users or categories of other users; or (2) implementation of alternative management practices, procedures, and methods.” Thus, supplies from the Edwards Aquifer may be less than the pumpage limits specified in SB 1477. For purposes of this analysis, the supply from the Edwards Aquifer is included at 340,000 acft/yr.
Development of surface water resources has been limited in the South Central Texas Region because of the presence of significant quantities of groundwater. The largest run-of-river water rights are concentrated in the lower Guadalupe-San Antonio River Basin and are held by the Guadalupe-Blanco River Authority, Union Carbide Corporation, DuPont, and the City of Victoria. These diversion rights total about 225,000 acft/yr. Significant water rights associated with existing reservoirs are held by the Guadalupe-Blanco River Authority (Canyon Reservoir), Bexar-Medina-Atascosa Counties WCID #1 (Medina Lake System), San Antonio City Public Service (Calaveras and Braunig Lakes), and Central Power & Light (Coleto Creek Reservoir). Diversion rights associated with these reservoirs total about 177,000 acft/yr.
Water Demand and Water Supply Comparisons
The South Central Texas Region water supply and demand data are shown graphically, by decade, for the years 2000 to 2050. The amount by which drought demand exceeds current supply is defined, for regional planning purposes, as the needs. In year 2000, needs (shortages) are 494,874 acft/yr, in 2030 the projected need is 670,948 acft/yr, and in 2050 the projected need for drought of record conditions is 785,725 acft/yr (Figure ES-5).
Figure ES-5. Supply, Demand, and Need (Shortage)
Figure ES-6 shows the
projected water needs for the region at each decade. In 2010, the projected need (shortage) for municipal, industrial,
steam-electric, and mining is approximately 210,000 acft/yr, and the need
for irrigation is about 310,000 acft/yr.
The projected needs in 2050 are about 505,000 acft/yr for
municipal, industrial, steam-electric, and mining, and about
Figure ES-6. Projected Water Needs (Shortages)
280,000 acft/yr for irrigation. Twelve of the counties in the region have municipal water user groups for which there are projected shortages (Figure ES-7). Figure ES-8 shows the names and locations of the 40 municipal water user groups that have projected needs during the projection period. There are four counties with projected industrial water needs (shortages) (Figure ES-9), two counties with projected steam-electric power generation water needs (Figure ES-10), ten counties with projected irrigation water needs (Figure ES-11), and six counties with projected mining water needs (shortages) (Figure ES-12). Needs (shortages) are not indicated in Figures ES-7 through ES-12 for water user groups capable of meeting their needs by renewal of a current water supply contract.
Figure ES-7. Counties with Projected Municipal Needs (Shortages)
Figure ES-8. Cities with Projected Needs (Shortages)
Figure ES-9. Counties with Projected Industrial Needs (Shortages)
Figure ES-10. Counties with Projected Steam-Electric Needs (Shortages)
Figure ES-11. Counties with Projected Irrigation Needs (Shortages)
Figure ES-12. Counties with Projected Mining Needs (Shortages)
Social and Economic Impacts of Not Meeting Projected Water Needs
The SCTRWPG identified 66 individual water user groups that showed an unmet need during drought-of-record supply conditions for each decade from 2000 to 2050. Of the 21 counties of the South Central Texas Region, 14 have water user groups with projected water needs (shortages). Compared to the baseline projected growth in population, the region could expect 807,923 fewer people in 2010, 1.3 million fewer in 2030, and 2.0 million fewer in 2050 if the projected water needs are not met. The expected 2050 population under the unmet water need (shortage) condition would be 44 percent lower than in the region’s most likely growth projection. School enrollment estimates for the region are 206,369 less in 2010, 328,528 less in 2030, and 500,891 less in 2050 than if the projected water needs are met.
The estimated effect of projected water shortages upon gross value of business, which includes the direct and indirect effects, are $31.9 billion per year in 2010, $52.4 billion per year in 2030, and $78.8 billion per year in 2050. If the water needs are left entirely unmet, the level of shortage in 2010 results in 461,698 fewer jobs than would be expected if the water needs of 2010 are fully met. The gap in job growth due to water shortages grows to 748,081 by 2030 and to 1.1 million by 2050. The estimated effects of the projected water shortages upon personal income in 2030 are $21.02 billion annually (1999 dollars), and in 2050 are $31.14 billion annually (1999 dollars).
Water Management Strategies to Meet Projected Water Needs
The regional water planning process included making projections of water needs of each water user group; identifying water management options and strategies through public input; and evaluation of each strategy in accordance with TWDB Rules, including calculation of potential quantity of water during drought conditions, reliability of supplies, cost of water delivered to the water users’ distribution systems in a form ready to be distributed for end use, environmental and implementation issues, effects upon other water resources of the state, threats to agricultural and natural resources, consistency comparisons among options and strategies, recreational effects, third party social and economic impacts of voluntary transfers, efficient use of existing supplies, and effects upon navigation. The planning process for the South Central Texas Region is summarized in Figure ES-13.
Figure ES-13. Regional Planning Process
South Central Texas Regional Water Plan
Water Plan Summary: The South Central Texas Regional Water Plan includes water management strategies which emphasize water conservation and reuse; maximize utilization of available resources, water rights, and reservoirs; avoid development of large new reservoirs; and minimize depletion of storage in aquifers. The Plan recognizes and includes several projects that are in various stages of implementation at this time, but are not yet complete. Additional strategies have significant support within the region, yet require further study regarding quantity of dependable water supply made available during severe drought, feasibility, and/or cost of implementation, are also included in the Plan. The water management strategies included in the South Central Texas Regional Water Plan could produce new supplies totaling 744,053 acft/yr in 2050 and may be categorized by source, as shown in Figure ES-14.
Specific water management
strategies in the Plan are summarized by source category below and by phased
implementation in Figure ES-15. Water
management strategies
Figure ES-14. Sources of New Supply
Figure ES-15. Phased Implementation of Water Management Strategies
emphasizing conservation and reuse are expected to provide about 21 percent of new supplies available in the year 2050 and include:
· Municipal Demand Reduction (Conservation) (L-10 Mun.);
· Irrigation Demand Reduction (Conservation) with Transfer (L-10 Irr.);
· SAWS Recycled Water Program;
· Aquifer Storage & Recovery (ASR) (SCTN-1a); and
· Irrigation Demand Reduction (Conservation) (L-10 Irr.).
Water management strategies maximizing use of available resources, water rights, and reservoirs are expected to provide about 61 percent of new supplies available in the year 2050 and include:
· Edwards Irrigation Transfers (L-15);
· Canyon Reservoir – River Diversion (G-15C);
· Canyon Reservoir – Wimberley, Woodcreek, & Blanco (G-24);
· Lower Guadalupe River Diversions (SCTN-16);
· Colorado River Diversion (LCRA)[3];
· Simsboro Aquifer (SCTN-3c);
· Purchase Water from Major Provider (PMP); and
· Desalination of Seawater (SCTN-17).
Water management strategies that simultaneously develop groundwater supplies and minimize depletion of storage in regional aquifers are expected to provide about 11 percent of new supplies available in the year 2050 and include:
· Edwards Recharge – Type 2 Projects (L-18a);
· Carrizo Aquifer – Wilson & Gonzales (CZ-10C);
· Carrizo Aquifer – Gonzales & Bastrop (CZ-10D); and
· Carrizo Aquifer – Local Supply (SCTN-2a).
Projects recognized in the Plan that are presently being implemented are expected to provide about 7 percent of new supplies available in the year 2050 and include:
· Schertz-Seguin Water Supply Project (SSWSP);
· Western Canyon Regional Water Supply Project (WCRWSP);
· Hays / IH-35 Water Supply Project (HIH35WSP);
· Lake Dunlap WTP Expansion and Mid-Cities Water Transmission System (CRWA);
· Carrizo Aquifer – Bexar & Guadalupe (BMWD);
· Trinity Aquifer – Bexar (BMWD); and
· Canyon Reservoir Contract Renewal (GBRA).
The Regional Water Plan includes several water management strategies that require further study and funding prior to implementation. Several of these strategies employ technologies that have been used previously, but further research is necessary to determine the cost of implementation, optimal scale and location, and quantity of dependable water supply that would be available in severe drought. These strategies are:
· Brush Management (SCTN-4);
· Weather Modification (SCTN-5);
· Rainwater Harvesting (SCTN-9);
· Additional Municipal Recycling (Reuse) Programs;
· Small Aquifer Recharge Dams;
· Cooperation with Corpus Christi for New Water Sources; and
· Additional Storage (ASR and/or Surface).
Although specific quantities of new supply dependable in drought have not been determined for these strategies, it is understood that their implementation will contribute positively to storage and system management of many diverse strategies in the Regional Water Plan. The SCTRWPG recommends that State funding be made available to cooperatively support the refinement and implementation of these strategies.
The Regional Water Plan also includes the Edwards Aquifer Recharge and Recirculation Systems (R&R). The SCTRWPG recommends State and local funding for research at a level that would ensure consideration of this strategy in the next 5-year planning cycle. However, this management strategy may not be implemented unless the Plan is specifically amended to allow implementation.
Following publication of the Initially Prepared Plan (IPP) on August 17, 2000, the Regional Water Planning Group carefully reconsidered the R&R strategy in light of its fundamental importance to many interests. The IPP included a footnote (IPP at pages ES-25 and 5-8) that indicated the strategy was included for research but not for implementation “unless the Plan is specifically amended to allow implementation.” In place of that footnote, the final Regional Water Plan includes a fuller discussion of the issue in Section 5.
The SCTRWPG members agree that the Recharge and Recirculation strategy may hold great promise and that optimizing use of the Edwards Aquifer is a cornerstone of water policy for the Water User Groups dependent on this underground source. They support inclusion of this strategy in the Regional Water Plan for purposes of assuring continued research, which is needed to show that this strategy will not adversely affect flows at Comal Springs. The SCTRWPG members agree that implementation of the strategy will require an amendment of the Regional Plan. The amendment process can occur at any time after formal approval of the Regional Water Plan and requires a public hearing after a 30-day notice period.
The members of the South Central Texas Regional Water Planning Group have further agreed that the Recharge and Recirculation strategy must move as expeditiously as possible through the necessary phases of research to resolve uncertainties about how it could work in practice. To this end, the Planning Group members agree to support the accelerated research effort in the manner appropriate to each, whether by providing funding, reviewing research findings, offering in-kind services, or other means. The goal of this effort will be to conclude the research as soon as practicable, possibly within a three-year period and in any case in time for reviewing results for possible inclusion of this strategy in the next planning cycle. In this way, the Regional Water Planning Group intends to maintain its consensus approach to planning with careful regard for all interests it represents across the South Central Texas Region.
The Lockhart Reservoir is recommended as a potential reservoir site. Although the Regional Plan recommends other means of meeting projected water needs in Caldwell County, the SCTRWPG recognizes the strong interest of local government to shift from low-quality groundwater sources to a surface water supply system. The reservoir is considered by the City of Lockhart and Caldwell County leaders to be an important economic development project to create new growth opportunities for the area. There are questions about economic feasibility at present, but the SCTRWPG recognizes the efforts in Caldwell County and by the Guadalupe Blanco River Authority to find a viable strategy to move the project forward. When that strategy is ready, the SCTRWPG will review the Lockhart Reservoir water supply option as a possible amendment to the Regional Water Plan.
There are significant quantities of projected water supply needs or shortages in the region for municipal, industrial, steam-electric, and mining uses. As indicated in Figure ES-15, implementation of a number of water management strategies on an expedited basis will be necessary to avoid significant hardship, water rationing, and/or cessation of discharge from Comal Springs in the event of severe drought during the next decade. Substantial water supply needs or shortages are also projected for irrigation use in the South Central Texas Region. However, based upon present economic conditions for agriculture and the fact that there are no really low-cost water supplies to be developed, the SCTRWPG has determined that it is not economically feasible to meet projected irrigation needs at this time, since the net farm income to pay for water is less than the costs of water at the potential sources. However, installation of Low Energy Precision Application (LEPA) equipment in six counties is recommended as part of the Irrigation Demand Reduction (Conservation) (L-10 Irr.) water supply strategy included in the Plan. During the next planning cycle, the RWPG intends to examine agricultural needs throughout the region and to undertake additional socio-economic studies of Regional Water Plan impacts on agricultural resources. It will also review water management strategies that may meet irrigation needs during the planning period of 2005–2055.
Implementation of the South Central Texas Regional Water Plan could result in the development of almost 750,000 acft/yr of new water supplies that will be reliable in the event of a repeat of the most severe drought on record. Costs associated with the implementation and long-term operations and maintenance of water management strategies have been estimated in accordance with TWDB rules and general guidelines and reflect regional water treatment capacity and balancing storage facilities sufficient to meet peak daily and seasonal water demands in the larger urban areas. Projected annual and unit costs for the South Central Texas Regional Water Plan are summarized by decade.
Annual costs for the development of new supplies in the South
Central Texas Regional Water Plan (in 1999 dollars) are estimated to range from
a low of about $120 million in the immediate future, as some of the least
costly water management strategies are developed, to a high of about $420
million in 2040, at which time Desalination of Seawater (SCTN-17) is projected
to be implemented (Figure ES-16).
Estimated unit costs for the development of new
