73Summary of Lower Colorado (K) Region

Llano

Travis

Mills

Burnet

Hays

Wharton

Fayette

Gillespie

Bastrop

San Saba

Colorado

Williamson

Blanco

Matagorda

Colorado River

Colorado River

CitiesMajor riversRegion K

Carrizo-Wilcox Aquifer (outcrop)Carrizo-Wilcox Aquifer (subsurface)Edwards (Balcones Fault Zone) Aquifer (outcrop)Edwards (Balcones Fault Zone) Aquifer (subsurface)Edwards-Trinity (Plateau) AquiferGulf Coast AquiferTrinity Aquifer (outcrop)Trinity Aquifer (subsurface)Ellenburger-San Saba Aquifer (outcrop)a

Ellenburger-San Saba Aquifer (subsurface)a

Hickory Aquifer (outcrop)a

Hickory Aquifer (subsurface)a

Existing reservoirs

aMinor aquifer (only shown where there is no major aquifer).

Marble Falls Aquifera

Queen City Aquifer (outcrop)a

Queen City Aquifer (subsurface)a

Sparta Aquifer (outcrop)a

Sparta Aquifer (subsurface)a

Yegua-Jackson Aquifera

Summary of Lower Colorado (K) Region

The Lower Colorado Regional Water Planning Area is composed of all or parts of 14 counties, stretch-ing from Mills County in the Hill Country southeast to Matagorda County on the Gulf Coast (Figure K.1). Most of the region lies in the Colorado River Basin. Major cities in the region include Austin, Bay City, Pflugerville, and Fredericksburg. The largest economic sectors in the region include ag-riculture, government, service, manufacturing, and retail trade. The manufacturing sector is pri-marily concentrated in the technology and semi-conductor industry in the Austin area. Oil, gas, as well as petrochemical processing, and mineral production, are found primarily in Wharton and Matagorda counties near the coast. The members of the Lower Colorado Planning Group are listed on the last page of this summary.

Population and Water DemandsIn 2010, just over 5 percent of the state’s total population is projected to reside in the Lower Colorado Region, and between 2010 and 2060 its population is projected to increase by nearly 100 percent to 2,713,905 (Figure K.2). Water de-mands, however, are projected to increase less significantly. By 2060, the region’s total water demand is projected to increase by 21 percent, from 1,078,041 acre-feet in 2010 to 1,301,682 acre-feet (Figure K.3). Agricultural irrigation wa-ter use accounts for the largest share of demands through 2050, but by 2060, municipal demand in all forms (including County-other) is expected to overtake irrigation (Table K.1). Municipal de-mand is projected to increase by 95 percent from

Figure K.1. Lower Colorado Region.

PLAN HIGHLIGHTS

@ Total capital cost $358 million

@ Wastewater reuse, water conservation, and desalination strategies would produce 367,973 acre-feet of water in 2060

@ Lower Colorado River Authority and San Antonio Water System Project, consisting of off-channel reservoirs and groundwater development, is recommended to provide water for Regions K and L

Water for Texas 200774

2010 to 2060, rising from 226,437 acre-feet to 442,110 acre-feet. Steam-electric water demand will increase by 45 percent, from 153,522 acre-feet to 222,058 acre-feet in the same time pe-riod. Agricultural irrigation demand is expected to decline by 21 percent, from 589,705 acre-feet in 2010 to 468,763 acre-feet in 2060.

Existing Water SuppliesThe region has a large number of surface water and groundwater sources available. In 2010, sur-face water is projected to provide about 77 per-cent of supplies and groundwater about 23 per-cent. The principal surface water supply sources are the Colorado River and its tributaries, includ-ing the Highland Lakes system. There are 9 reser-voirs in the Region K plan from which water supply is calculated. In determining water supply from the Colorado River, the planning group assumed voluntary subordination of its major senior water rights to those in Region F for planning purposes only. Assumptions used to determine existing sup-plies from the Colorado River have no legal effect. There are 10 major and minor aquifers that supply groundwater to users in the region. The five major aquifers providing groundwater supplies are the Edwards-Trinity (Plateau) and Trinity in the west-ern portion of the region, the Edwards (Balcones Fault Zone) and Carrizo-Wilcox in the central por-tion, and the Gulf Coast in the eastern portion. The total supply to the planning area is estimated to be 1,182,078 acre-feet in 2010, declining 25 per- cent to 887,972 acre-feet in 2060, because of res-ervoir sedimentation and expired water supply contracts (Table K.2).

Needs Water user groups in the Lower Colorado Region are anticipated to need 246,055 acre-feet of addi-tional water in 2010 and 557,311 acre-feet by 2060 under drought conditions (Figure K.4, Table K.3). However, about 61 percent of the 2060 needs can be met by renewing current water supply contracts with wholesale providers. All six water use sectors show needs for additional water by 2060. In 2010, the agricultural irrigation sector has the largest needs, 218,550 acre-feet or 89 percent of total. However, in 2060, municipal has approximately half the needs, 277,674 acre-feet, due to popu-lation growth over the planning period. Irrigation needs in 2060 decline to 116,320 acre-feet.

Figure K.2. Projected population for 2010–2060.

0

500

1,000

1,500

2,000

2,500

3,000

Projected average annual growth rateRegion K = 1.39%Texas = 1.21%

Popu

latio

n(th

ousa

nds)

2010 2020 2030 2040 2050 2060

Table K.1. Projected water demands for 2010–2060

Category2010

(acre-feet)2060

(acre-feet)

Percent change in demand 2010–2060

Percent of overall demand

in 2010

Percent change in relative share

of overall demand, 2010–2060

Municipal 226,437 442,110 +95 +21 +13

County-other 26,200 42,060 +61 +2 +1

Manufacturing 38,162 85,698 +125 +4 +3

Mining 30,620 27,598 -10 +3 -1

Irrigation 589,705 468,763 -21 +55 -19

Steam-electric 153,522 222,058 +45 +1 +3

Livestock 13,395 13,395 0 +1 0

Region 1,078,041 1,301,682 +21

75Summary of Lower Colorado (K) Region

0

200

400

600

800

1,000

1,200

1,400

2010 2020 2030 2040 2050 2060Th

ousa

nds

of a

cre-

feet

Livestock

MiningSteam-electric

Municipal

County-otherManufacturing

Irrigation

Existing supplies

Figure K.3. Projected total water demand and existing water supplies for 2010–2060.

Figure K.4. Projected water needs for 2010–2060.

0

100

200

300

400

500

600

188 188 188 188 188 188218,550 197,660 179,196 161,554 144,573 116,320

13,550 13,146 12,366 6,972 5,574 5,7940 401 27,720 81,467 86,351 112,867

4,315 9,617 14,409 16,056 20,297 22,0961,805 5,507 8,811 12,241 18,127 22,3727,647 14,817 38,231 43,975 84,469 277,674

IrrigationMiningSteam-electricManufacturingCounty-otherMunicipal

2010 2020 2030 2040 2050 2060Livestock

Thou

sand

s of

acr

e-fe

etTh

ousa

nds

of a

cre-

feet

2010 2020 2030 2040 2050 2060

100

200

300

400

500

600

700

800

900

0

Conservation

Groundwater

NeedsReuse

Surface water

Groundwaterdesalination

Aquifer storageand recovery

Figure K.5. Recommended water management strategy water supply volumes for 2010–2060.

Water for Texas 200776

Recommended Water Management Strategies and CostWater management strategies included in the Lower Colorado Regional Water Plan would provide 861,930 acre-feet of additional water supply by the year 2060 (Figure K.5) at a total capital cost of $358,174,068 for the region’s portion of the project (Appendix 2.1). The primary recommended water management strategy is the Lower Colorado River Authority/San Antonio Water System Project that consists of off-channel reservoirs, agricul-tural water conservation, additional groundwater development, and new and/or amended surface water rights. The majority of new surface water will be captured in off-channel reservoirs for use by San Antonio, while the groundwater will remain within the region to meet agricultural needs. The costs associated with this project will be paid for by San Antonio and are included in the 2006 Region L Regional Water Plan. There are no unmet needs in the plan.

Conservation RecommendationsConservation strategies represent 23 percent of the total amount of water resulting from all rec-ommended water management strategies. Water conservation was included as a strategy for every municipal water user group with a need and

water use greater than 140 gallons per capita per day. The plan recommends that all nonmunicipal water user groups with needs reduce their water use through conservation by 3, 5, and 7 percent in 2010, 2020, and 2030, respectively.

Ongoing IssuesRegion K is concerned that some groups may oppose the Lower Colorado River Authority/San Antonio Water System Project. Feasibility studies for this project are at about the midpoint of the scheduled seven-year time period. The project can not go forward until all studies are completed, the project is found to be feasible, and all statutory and permitting requirements are satisfied.

Select Policy Recommendations• Provide instream flows and freshwater

inflows to bays and estuaries

• Use surface water and groundwater conjunctively for maximum efficiency and to avoid depleting either source

• Achieve sustainable growth, development, and water use

• Promote agricultural and municipal conservation and wastewater reuse

Table K.2. Existing water supply sources supplies for 2010 and 2060

Water supply source2010

(acre-feet)2060

(acre-feet)

Surface water Colorado River run-of-river 464,601 471,402 Highland Lakes system 380,106 72,477 Colorado River combined run-of-river irrigation 25,629 25,629 Other local supply 18,378 26,124 Other surface water 26,330 26,807

Surface water subtotal 915,044 622,439 Groundwater Gulf Coast Aquifer 158,936 158,511 Hickory Aquifer 22,920 22,920 Ellenburger-San Saba Aquifer 21,384 21,365 Marble Falls Aquifer 15,147 15,147 Carrizo-Wilcox Aquifer 13,768 13,650 Other groundwater 34,879 33,940

Groundwater subtotal 267,034 265,533 Region total 1,182,078 887,972

Note: Water supply sources are listed individually if 10,000 acre-feet per year or greater in 2010.Only includes supplies that are physically and legally available to users during a drought of record.

77Summary of Lower Colorado (K) Region

Tabl

e K.

3. W

ater

nee

ds (

acre

-fee

t pe

r ye

ar)

by c

ount

y an

d ty

pe o

f us

e in

yea

rs 2

010

and

2060

Coun

ty

Tota

lM

unic

ipal

Coun

ty-o

ther

Man

ufac

turi

ngSt

eam

-ele

ctri

cM

inin

gIr

riga

tion

Live

stoc

k

2010

2060

2010

2060

2010

2060

2010

2060

2010

2060

2010

2060

2010

2060

2010

2060

Bas

trop

4,4

20

29,

032

—

10,

629

—

9,5

76

8

60

—

8,7

50

4,2

93

—

119

1

7 —

—

Bla

nco

123

2

64

—

—

122

2

63

1

1

—

—

—

—

—

—

—

—

Bur

net

1,6

18

10,

120

296

6

,584

6

11

2,6

15

—

—

—

—

688

8

98

—

—

23

23

Col

orad

o 6

2,60

1 2

4,97

2 —

—

1

05

90

—

—

—

—

8,5

69

4,86

7 53

,902

19

,990

2

5 2

5

Fay

ette

332

3

3,23

0 3

7 2

,083

2

08

16

45

162

—

3

0,90

8 —

2

9 2

0 1

0 2

2 2

2

Gill

espi

e —

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

Hay

s 2

,066

1

8,77

9 1

,307

8

,708

7

59

9,7

38

—

333

—

—

—

—

—

—

—

—

Llan

o 8

05

2,6

66

740

2

,527

—

7

4 3

3

—

—

—

—

—

—

6

2 6

2

Mat

agor

da 9

7,50

3 1

31,5

54

2

2

—

—

—

13,5

15

—

52,

766

—

—

97,4

45

65,2

15

56

56

Mill

s 6

97

544

3

57

357

—

—

1

1

—

—

—

—

3

39

186

—

—

San

Sab

a —

5

—

5

—

—

—

—

—

—

—

—

—

—

—

—

Tra

vis

7,8

25

273

,042

3

,444

2

44,5

04

—

—

4,25

7 8

,013

—

2

0,44

3 —

—

1

24

82

—

—

Wha

rton

66,

601

30,

828

—

—

—

—

—

8

—

—

—

—

66,6

01

30,8

20

—

—

Will

iam

son

1,4

64

2,2

75

1,4

64

2,2

75

—

—

—

—

—

—

—

—

—

—

—

—

Reg

ion

246,

055

557

,311

7

,647

2

77,6

74

1,80

5 22

,372

4,

315

22,0

96

—

112,

867

13,

550

5,79

4 21

8,55

0 11

6,32

0 1

88

188

Water for Texas 200778

SELECT MAJOR WATER MANAGEMENT STRATEGIES (Dollar amounts are rounded.

See Appendix 2.1 for all recommended strategies and actual costs.)

@ Lower Colorado/San Antonio Water System Project would provide up to 377,000 acre-feet per year for users in Regions K and L—Implementation by: 2020; Capital Cost: $2 billion (All capital costs are included in 2006 Region L Regional Water Plan).

@ New water pipelines to Hays County (2 strategies)—Implementation by: 2010; Capital Cost: $13 million.

@ Wastewater reuse by Austin and return flows would produce 144,090 acre-feet per year—Implementation by: 2010; Capital Cost: $178 million.

@ Desalination of brackish groundwater by South Texas Project Electrical Generating Station would produce 29,568 acre-feet per year—Implementation by: 2010; Capital Cost: $97 million.

Lower Colorado Planning Group Members and Interests Represented

Voting members during adoption of 2006 Regional Water Plan:John Burke (Chair), water utilities; Jim Barho, environmental; David Deeds, municipalities; Ronald G. Fieseler, environmental; Rick Gangluff, electric generating utilities; Ronald Gertson, small business; Barbara Johnson, industries; Mark Jordan, river authorities; D.C. (Chris) King, counties; Teresa Lutes, municipalities; Julia Marsden, public; William M. (Bill) Miller, agriculture; Bill Neve, counties; W.R. (Bob) Pickens, other; W.A. (Billy) Roeder, counties; Haskell Simon, agriculture; Harold Streicher, small business; James Sultemeier, counties; Paul Tybor, water districts; Roy Varley, other; Jennifer Walker, environmental; Del Waters, recreation

Former voting members during 2001-2006 planning cycle:Dede Armentrout, environmental; Steve Balas, agriculture; Stovy Bowlin, water districts; Robert Dickerson, small business; Gerald Hajovsky, counties; Dale Henry, counties; Dennis Jones, municipalities; Jobaid Kabir, river authorities; Quentin Martin, river authorities; Charles Martinez, municipalities; Stanley Reinhard, water districts; Cole Rowland, other (recreation); Mark Smith, industries; Bill Stewart, other (recreation)