1

Groundwater Availability Modeling Groundwater Availability Modeling (GAM) for the Lipan Aquifer(GAM) for the Lipan Aquifer

Presented toPresented to

Stakeholder Advisory ForumStakeholder Advisory ForumSan Angelo, TexasSan Angelo, Texas

July 31, 2003July 31, 2003

LBG-GUYTON

Associates

PEC OS

W EBB

BR EWSTER

H U D SPET H

PR ESIDIO

R EEVES

C U LBER SON

VAL VER D E

D U VAL

TERR ELL

C R OC KETT

KEN ED Y

FR IO

HAR R IS

HI L L

BELL

BEE

C L AY

POL K

ED WAR D S

JEFF D AVIS

KERR

GAIN ES

LEON

U VALD E

H ALE

D ALL AM

IRION

D IMMIT

L AMB

KIN G

BEXARKIN N EY

STAR R

H AL L

WISEJ AC K

UPTON

H ID AL GO

S U TTON

C ASS

OLD H AM

EL LIS

MED IN A

KIMBLE

Z AVAL A

KENT

R USK

LEE

LYN N

GR AY

C OKE

L A SALLE

MIL AM

ER ATH

H AR TL EY

H U N T

BR AZO R IA

SMITH

KN OX

FLOYD

L LAN O

A N D R EWS

TYL ER

TRAVISLIBER TY

J ONES

N U EC ES

R EA GAN

BOW IE

W AR D

ZAPATA

L AMAR

R EAL

N OLAN

TER R Y GAR ZA

MIL LS

C OL EMAN

EC TOR

TOM GR EEN

MASON

YOU N G

FALLS

CAMER ON

MAT AGOR D A

H AY S

BR OW N

C OOKE

JASPER

D EAF SMITH

BU R N ET

M AVER IC K

H OU STON

L AVAC A

FISH ER

C OLLIN

MOOR E

FAN N IN

M OTLEY

MAR TIN

L IVE OAK

D AL LAS

EL PASO

BAILEY

B OSQU E

H ARD IN

KLEBERG

J IM HOGG

TAYLOR

C OT TL E

POTTER

D ON LEY

GOLIAD

SAN SABA

ATASC OSA

D EN TON

C ORYEL LC R ANE

C ONC H O

BAYL OR

D E WITT

BR OOKS

PAR KER

R U N N ELS

N AVAR R O

AR C H ER

C ARSON

C ASTR O

WOOD

SC U R R Y

C R OSBY

FAYETTE

McMU L L EN

W H AR TON

BOR D EN

C AL H OUN

SH EL BY

MEN AR D

GIL LESPIE

PAR MER

WILSON

D IC KEN S

SC H LEIC H ER

GR IMES

F OAR D

PA N OLA

H ASKELL

BR ISC OE

R AN D AL L

D AW SON

MID L AN D

HOW AR D

Mc LEN N AN

GON ZA L ES

GR AYSON R ED R IVER

SW ISH ER

R OBERTS

H OC KL EY

A N DER SON

TAR R ANT

WALKER

L UBBOC K

VIC TOR IA

BASTROPJ EFFER SON

SHER MAN

WH EELER

MITC H ELL

YOAKU M

STER LIN GW IN KL ER

TRIN ITY

HEMPH ILL

W IL BA R-GER

C OMAN -C HE

WA

LL ER

KAR N ES

LIPSC OMB

JAC KSON

W IL LIAMSON

R EFU G IO

WILLAC Y

LOVIN G

AU STIN

EASTLAN D

H OPKIN S

Mc C U LL OC H

BL AN C O

H AR R ISONSTEPH EN S

AN GELIN A

CALL AH AN

C OLOR AD O

H AN SFOR D

K AU FMAN

BAN D ER A

PALO PIN TO

MON TAGU E

H AMILTO N

OC H IL TR EE

C OM AL

LIMEST ON ESABIN E

C OC H R AN

FORT BEN D

C H AMBE R S

VAN ZAN D T

WIC HITA

JOH N SON

STON EWAL L

H EN D ER SON

TITU S

FR EESTON E

MON TG OMER Y

H OOD

KEN D AL L

BR AZ OS

GAL VESTON

U P SH U R

H U TC H IN SON

L AMPAS AS

BU RL ESON

H AR D EMAN

GU AD ALU PE

CH IL D-RE SS

AR M-STR ON G

GL AS S-C OCK

N AC OG-D OC H ES

MAR ION

C ALD WELL

MAD ISON

OR AN GE

D ELTA

R AIN S

GRE GG

CAMP

MO

RR

IS

FR

ANKLIN

ROCK -W ALL

C OLLI NGS-W ORTH

THR OC K-MOR TON

SOME R-VE L

S ANA UGUS-

TI N E

S ANJAC IN TO

J IMWELL S

S HACK EL -FORD

C HE RO-KEE

NEW

TON

R OBE RT-S ON

WA SH ING-TON

AR A N-SA SS AN

P ATRIC I O

80

79

67

78

85

82

6876

69

81

75

77

87

71

72

73

74

8 4

86

83

46

47

66

53

45

54

56

50

65

38

64

41

51

16

59

42

49

39

63

48

40

61 57

44

37 55

58

62

43

60

52

36

70

29

6

14

17

35

15

9

25

3328

8

7

12

3

345

26

32

30

23

21 10

11

27

20

18

22

19

24

13

2

31

4

1

PECOS

WEBB

BREWSTER

HUDSPETH

PRESIDIO

REEVES

CULBERSON

VAL VERDE

DUVAL

TERRELL

CROC KETT

FRI O

HARRIS

HILL

BELL

BEE

KEN EDY

CLAY

POLK

EDWARDS

JEFF DAVIS

GAINES

LEON

KERR

UVALDE

HALE

DALLAM

KI NG

IRIO N

LAMB

DIMMI T

BEXARKI NNEY

STARR

HALL

JACK

CASS

WISE

SUTTON

OLD HAM

HIDALGO

ELLIS

UPTO N

ZAVALA

MEDI NA

KI MBLE

RUSK

LEE

LYNN KENT

GRAY

LA SALLE

COKE

MILAM

ER ATH

HARTLEY

HUNT

SMITH

KNOX

FLOYD

LLANO

TYLER

BRAZORIA

ANDREWS

TRAVIS LIBERTY

REAGAN

JONES

ZAPATA

LAMAR

BO WIE

NUECES

WARD

REAL

NOLAN

TERRY GARZA

COLEMAN

MILLS

ECTOR

YOUNG

TOM GREEN

MASON

FALLS

MAVERIC K

BURNET

HAYS

DEAF SMITH

JASPER

LAVACA

HOUSTON

COO KE

FISHER

BROW N

COLLIN

MOORE

MOTLEY

FANNIN

MARTIN

EL PASO

BAI LEY

DALLAS

LIVE OAK

BO SQU E

HARDIN

JIM HOGG

TAYLOR

CAMERON

POTTER

GOLIAD

CRANE

COTTLE

DONLEY

ATASCO SA

SAN SABA

DENTON

CORYELL

BAYLOR

CONCHO

BROOKS

RUNNELS

PARKER

NAVARRO

ARCHER

DE WITT

CARSON

SC URRY

MATAGORDA

CROSBY

KLEBERG

FAYETTE

SHELBY

WOOD

CASTR O

BORDEN

MENARD

WHARTON

NEWTON

PARMER

GILLESPIE

MCMULLEN

DICKENS

SCHLEICHER

FOARD

HASKELL

PAN OLA

GRIMES

MIDLAND

WILSON

RANDALL

BRISCOESW ISHER

DAWSON

GRAYSON

GONZALES

HOW ARD

RED RI VER

ROBERTS

HOCKLEY

TARRANT

AN DERSON

MCLENNAN

LUBBOCK

CALHOUN

CHEROKEE

VICTORIA

BASTROP

WALKER

SHERMAN

YOAKUM

MITCHELL

STERLING

HEMPHILL

WHEELER

KARNES

TRINITY

WINKLER

JACKSON

LIPSCO MB

LOVING

WILLIAMSON

AUSTIN

EASTLAND

REFU GIO

HOPKINS

HARRISON

BLANCO

CALLAHAN

COLORADO

ANGELINA

MCCULLOCH

STEPHENS

WILLACY

JEFFERSON

KAUFMAN

BANDERA

HANSFORD

COMANCHE

MO NTAGUE

PALO PINTO

JIM WELLS

LIMESTONE

COM AL

HAMILTON

OCHI LTREE

WILBARGER

SABI NE

COCH RAN

CHAMBERS

FO RT BEND

VAN ZANDT

HENDERSON

STONEWALL

JOHNSON

FREESTONE

MONTGOMERY

GLASSCOCK

KEN DALL

TITUS

BRAZOS

HOOD

WICHITA

AR MSTRONG

UPSHUR

ROBERTSON

HUTCHINSON

LAMPASAS

CHILDRESS

WAL LER

NACOGDOCHES

SHACKELFOR D

BURLESO N

HARDEMAN

GUADALUPE

GALVESTON

MARI ON

THR OCKM OR TON

COLLIN GSWORTH

MADI SON

CALDWELL

SAN PATRICIO

SAN JACI NTO

ARANSAS

WASHINGTON ORANGE

DELTA

RAINS

GREGG

SAN A UGUST IN

E

CAMP

MORRIS

FRAN

KLIN

SOMER-VELL

ROCK-WALL

Region F Brazos G

Panhandle

Far West Texas

Region C

East Texas

Region H

Llano Estacado

Plateau

Rio Grande

South Central Texas

Region B

Coastal Bend

Lower Colorado

North East Texas

Lavaca

P

D

K

N

B

M

L

J

O

H

I

C

E

A

GF

Groundwater Groundwater Availability ModelingAvailability Modeling

Contract ManagerContract ManagerTexas Water Development BoardTexas Water Development Board

2

• Purpose: to develop the best possible groundwater availability model with the available time and money.

• Public process: you get to see how the model is put together.

• Freely available: standardized, thoroughly documented, and available over the internet.

• Living tools: periodically updated.

GAMGAM

3

• …the amount of groundwater available for use.• The State does not decide how much

groundwater is available for use: GCDs and RWPGs decide.

• A GAM is a tool that can be used to assess groundwater availability once GCDs and RWPGs decide how to define groundwater availability.

What isWhat isgroundwatergroundwateravailability?availability?

4

• Water Code & TWDB rules require that GCDs use GAM information. Other information can be used in conjunction with GAM information.

• TWDB rules require that RWPGs use GAM information unless there is better site specific information available

Do we haveDo we haveto use GAM?to use GAM?

• The model– predict water levels and flows in response to

pumping and drought– effects of well fields

• Data in the model– water in storage– recharge estimates– hydraulic properties

• GCDs and RWPGs can request runs

How do weHow do weuse GAM?use GAM?

5

• GCDs, RWPGs, TWDB, and others collect new information on aquifer.

• This information can enhance the current GAMs.

• TWDB plans to update GAMs every five years with new information.

• Please share information and ideas with TWDB on aquifers and GAMs.

LivingLivingtoolstools

• SAF meetings– hear about progress on the model– comment on model assumptions– offer information (timing is important!)

• Report review– at end of project

• Contact TWDB– Robert Mace– Richard Smith

Participating inParticipating inthe GAM the GAM processprocess

6

Comments:Comments:

Richard SmithRichard Smithrichard.smith@twdb.state.tx.usrichard.smith@twdb.state.tx.us

(512)936(512)936--08770877www.twdb.state.tx.us/gamwww.twdb.state.tx.us/gam

Conceptual Model for Lipan Conceptual Model for Lipan Aquifer GAMAquifer GAM

7

Physiography Physiography and Climateand Climate

General Location Map

US HWY 87

RANCH RD 853

US HWY 67 S

US HWY 87

RANCH RD 380

US HWY 67STA

TE H

WY

208

San Angelo, TX

IRION

STER

LIN

G

COKE

TOM GREEN

RUN

NELS

CO

NCH

O

0 10

Miles

Key:CountiesRoads

CitiesStudy Area boundary

8

Physiographic Provinces Physiographic Provinces http://www.lib.http://www.lib.utexasutexas.edu/geo/.edu/geo/physographyphysography.html.html

• Central Texas (North-Central Plains)Shale Bedrock characterized by meandering rivers through local prairieHarder Bedrock forms hills and rolling plains dissected by rivers.Live oak ashe juniper parks grade westward into mesquite lotebushbrush.

• Edwards PlateauThe Edwards Plateau is capped by hard Cretaceous limestones. Local streams entrench the plateau as much as 1,800 feet in 15 miles. The upper drainages of streams are waterless draws that open into box canyons where springs provide permanently flowing water.Sinkholes commonly dot the limestone terrain and connect with a network of caverns. The vegetation grades from mesquite juniper brush westward into creosote bush tarbush shrubs.

General ClimateGeneral Climate(San Angelo, TX www.(San Angelo, TX www.sanangelosanangelo.org).org)

• San Angelo, TX Elevation is 1900 ft – Model Area Elevation Range is 1500 ft to 2500 ft

• Located Near the Northern Boundary of theChihuahuan Desert

• Average Morning Humidity of 79%, That Drops to an Average of 44% in the Afternoons

• average annual temperature is 64.9 degrees, with average highs of 78.1, and lows of 51.6.

• San Angelo receives 251 days of sunshine each year, and the average rainfall is 20.45 inches.

9

TWDB Aquifers

0 3 6 9 12Miles

Pecan CreekEDWARDS-TRINITY AQUIFER

IRION

COKE

RUNNELS

CONCHO

San Angelo, TXLIPAN AQUIFER

Twin Buttes Reservoir

O.H. Ivie Reservoir

O.C. Fisher Lake

Lake Nasworthy

Lake Ballinger/ Lake Moonen

Groundwater Conservation Districts

WCD = Water Conservation DistrictGCD = Groundwater Conservation DistrictUWCD = Underground Water Conservation DistrictUWD = Underground Water DistrictUWC = Underground Water Conservation

0 7.5 15 22.5 30Miles

LIPAN AQUIFER

Emerald UWCD

Lipan-Kickapoo WCD

Hickory UWCD No. 1

Irion County WCD

Coke CountyUWCD

Sterling County UWCD

Plateau UWC And Supply District

Menard County UWD

CROCKETT

IRION

COKECOLEMAN

TOM GREEN

MASON

BROWN

CONCHO

RUNNELS

MENARDSCHLEICHER

STERLING

McCULLOCH

San Angelo, TX

Study Area Boundary

10

!(

!(

!(

!(

Water Valley21.63

San Angelo Mathis20.35

OC Fisher22.12

Paint Rock25.08

TWDB Quad 607 Avg. Annual Precipitation = 22.11960 thru 1996

22 24

Mean Annual Rainfall 1960 thru 1996Mean Annual Rainfall 1960 thru 1996

TWDB Contours

NWS Contours (1960 – 1996)

Paint Rock25.08

Average Rainfall at Location 1960

thru 1996

Model boundary

Total Annual Precipitation 1940 - 2000

0

10

20

30

40

50

1940

1943

1946

1949

1952

1955

1958

1961

1964

1967

1970

1973

1976

1979

1982

1985

1988

1991

1994

1997

Year

Inch

es

Yearly total

10 year MovingAverage

Annual PrecipitationAnnual Precipitation(TWDB Quad 607)(TWDB Quad 607)

11

LipanLipan--Kickapoo WCD Rain GagesKickapoo WCD Rain Gages

+ Rain Gage Locations

Data Only Available from 2000 to Present

GeologyGeology

12

Surface Geology

Model boundary

PermianQuaternary

Cretaceous

Cretaceous Permian

Geologic Formations in the Model AreaGeologic Formations in the Model Area

• Leona Formation – Quaternary Alluvial Deposits Consisting Mainly of Gravels and Conglomerates Cemented with Sandy Lime

• Permian Formations – Primarily Limestone Units in the Model Area Including the Choza, Bullwagon, Vale, Standpipe, and Arroyo Formations

• Cretaceous Formations – Edwards –Trinity Formations Located to the South and West

13

Geologic History in Model AreaGeologic History in Model Area

• Permian Deposits Overlain by Quaternary Alluvium

• Rising and Falling Water Levels Created Karst Features

• Quaternary Alluvium Subsequently Filled These with Gravels and Conglomerates

• No Mapped Faults However there is Evidence of Recent Active Faulting in Kickapoo Creek

Stratigraphic and Hydrostratigraphic SectionStratigraphic and Hydrostratigraphic Section

14

San Angelo Sandstone

Choza Limestone

Bullwagon Dolomite

Arroyo Shale / Limestone

Vale Shale

Arroyo Shale/Limestone

Vale Shale

Choza Limestone

Bullwagon Dolomite

Standpipe aquifer

Geologic CrossGeologic Cross--Sections Sections (after Lee, 1986)(after Lee, 1986)

Driller’s Logs CrossDriller’s Logs Cross--SectionsSections

15

Section A Section A -- A’A’

Section B Section B –– B’B’

16

Section C Section C –– C’C’

Section D Section D –– D’D’

17

HydrostratigraphyHydrostratigraphy

Hydrostratigraphic PropertiesHydrostratigraphic Properties

• Leona, Cretaceous and Permian Units are Hydraulically Connected.

• In General they Behave as one Hydrostratigraphic Unit with no Observable Hydraulic Head Differences Related to Hydrostratigraphy

• Water Quality and Transmissivity Deteriorate with Depth

• Aquifer Productivity is Partially Influenced by Presence of Paleo-features with Higher Transmissivity

18

Why a One Layer Model?Why a One Layer Model?

• Most of the Leona Formation is Dry• Generally, Leona Gravels and Underlying

Permian Units are Hydraulically Indistinguishable

• There is no Data to Substantiate Vertical Gradients

• Most of the Larger Production Wells are in the Permian which Initially was not Designated as Part of the Lipan Aquifer

Hydrostratigraphic SectionHydrostratigraphic Section

Arroyo Shale/Limestone

Vale Shale

No Flow

Inflow from Edwards-Trinity

Precipitation(Recharge)

Pumping

Evaporation and ET

River (in or out)

Springs

Choza Limestone

Bullwagon Dolomite

Standpipe aquifer

19

Numerical Model Block DiagramNumerical Model Block Diagram

Lipan/Permian

W E

No Flow

RechargePumping

Groundwater-Surface Water

Interaction

Cross-Formational Flow

Springs

StructureStructure

20

Model boundary

Land Surface TopographyLand Surface Topography

Geophysical Log LocationsGeophysical Log Locations

59 Wells With

Geophysical Logs

21

Geophysical Log InterpretationGeophysical Log Interpretation

• On Some Logs, A Possible Lithologic Contact is Evident

• On Others, It is Difficult, if not impossible to Discern the Contact

Assumed Leona / Permian Contact

Used Geophysical Logs to Attempt to Locate the Base

of the Leona Formation

Picks were made on 48 of the 59 Logs

Leona Formation Base ElevationLeona Formation Base Elevation

Model boundary

Based on Geophysical Logs

Log Location

22

Total Thickness of the Leona FormationTotal Thickness of the Leona Formation

Model boundary

Based on Geophysical Logs

Log Location

Saturated Thickness of Leona Formation 1980Saturated Thickness of Leona Formation 1980

WETDRY

Model boundary

Based on Geophysical Logs

Log Location

Artifact of Grid Minus Grid Operation in Area of Little or No Data

WET

23

Permian GeologyPermian Geology

• Permian units predominantly act as a single hydrostratigraphic unit beneath the Lipan aquifer and are in direct communication with the Lipan aquifer

• Different Permian units are not distinguishable based on drilling logs or water levels

• Base of the aquifer will be 400 feet below ground surface

Water Levels Water Levels and and

Regional Groundwater FlowRegional Groundwater Flow

24

Regional Groundwater Flow Paths

Control points withwater level <1950 date

Predevelopment Groundwater Elevations from TWDB Database Predevelopment Groundwater Elevations from TWDB Database First Quarter (Jan First Quarter (Jan -- Mar) 1950 Filtered DataMar) 1950 Filtered Data

Model boundary

25

Water Levels Water Levels -- 19811981

Model boundary

Water Levels Water Levels -- 19901990

Model boundary

26

Water Levels Water Levels -- 20002000

Model boundary

Added LKWCD Data to TWDB Data

Ben Ficklin Dam

Lake

Lake

Lake

Lake Nasworthy

Lake Nasworthy

Lake Sunset

Parkview Lake

Parkview Lake

South Concho River

State Fish Hatchery

Dove Creek

Spring Creek

Lake Nasworthy

Lake Nasworthy

O C Fisher Lake

South Concho River

South Concho River

Spri ng Creek

Twin But tes Reservoir

Xqz Lake

South Cowcho River

Twin Buttes Reservoi r

0 20 40 60 80 100 120

Maximum Well Yield (gpm) 1 to 200 200 to 400 400 to 1004

1991- 2000 Head Decline (feet)

San Angelo

Water Level Decline 1991 Water Level Decline 1991 ––2000 Based on LKWCD 2000 Based on LKWCD DataData

27

Recharge and Recharge and EvapotranspirationEvapotranspiration

Sources of RechargeSources of Recharge

• Precipitation• Irrigation Return Flow• Stream and River Leakage• Lake and Pond Leakage• Injection Wells

28

Factor Influencing and Controlling RechargeFactor Influencing and Controlling Recharge

• Precipitation and Evapotranspiration• Soil Characteristics including Permeability and

Thickness• Geologic Controls – Structure, Rock Type and

Sat/Unsat Hydraulic Conductivity• Land Use / Land Cover

Vegetation DensityAgricultural AreasUrban AreaCrops and Irrigation

• Stream and River Flow characteristics• Topographic Slope

!(

!(

!(

!(

Water Valley21.63

San Angelo Mathis20.35

OC Fisher22.12

Paint Rock25.08

TWDB Quad 607 Avg. Annual Precipitation = 22.11960 thru 1996

22 24

Mean Annual Rainfall 1960 thru 1996Mean Annual Rainfall 1960 thru 1996

TWDB Contours

NWS Contours (1960 – 1996)

Paint Rock25.08

Average Rainfall at Location 1960

thru 1996

Model boundary

29

Soils MapSoils Map ((StatsgoStatsgo database)database)

USCS Classification

Lakes

Clays

Sandy Silty Clays

Clayey Gravel

Silty Gravels

Silts

Clayey Sands

Silty Sands

Model boundary

Soil Permeability (cm/hr)Soil Permeability (cm/hr)

http://www.essc.psu.edu/cgi-bin/essc.cgi?database&index.html

Model boundary

30

Soil Available Water Capacity (%)Soil Available Water Capacity (%)

Available Water Capacity2

3 - 7

8 - 12

13 - 17http://www.essc.psu.edu/cgi-bin/essc.cgi?database&index.html

Model boundary

Soil Thickness (cm)Soil Thickness (cm)

Model boundary

31

Nearby Recharge EstimatesNearby Recharge Estimates

Recharge Edwards- Seymour SouthernRate (in/yr) Trinity Ogallala

Min 0.30 1.00 0.05Max 2.00 2.60 8.62

Average 1.18 2.02 1.92Count 4 5 17

Aquifer

Recharge Analysis

0.301.00

0.05

2.002.60

8.62

1.182.02 1.92

0

2

4

6

8

10

Trinity Ogallala

Edwards- Seymour Southern

Inch

es p

er Y

ear

Average

Recharge in the ModelRecharge in the Model

• For yearly stress periods, initial recharge estimates will be spatially-varied distributed based on a percentage of mean annual precipitation

• For monthly stress periods, recharge will initially be distributed, both spatially and temporally, based on percentage of mean monthly precipitation.

• During calibration, recharge will be adjusted as necessary, within reasonable constraints, both temporally and aerially.

32

Palmer Drought IndexPalmer Drought Indexhttp://http://lwflwf..ncdcncdc..noaanoaa..govgov//oaoa/climate//climate/onlineprodonlineprod/drought/main.html/drought/main.html

Initial Estimate of Recharge as 4% of Mean Initial Estimate of Recharge as 4% of Mean Annual Historic PrecipitationAnnual Historic Precipitation

Model boundary

33

Is This Recharge Rate Reasonable?Is This Recharge Rate Reasonable?

1.1. Analysis of LongAnalysis of Long--Term Term pumping and waterpumping and water--levels levels indicate that Annual indicate that Annual Recharge is on the order of Recharge is on the order of 40,000 AFY40,000 AFY

2.2. Assuming Half of the Assuming Half of the recharge to the system is recharge to the system is due to Precipitationdue to Precipitation

3.3. Area of Lipan Aquifer from Area of Lipan Aquifer from TWDB Outline ~ 400,000 TWDB Outline ~ 400,000 AcresAcres

4.4. It is assumed that Lateral It is assumed that Lateral and Vertical Recharge are in and Vertical Recharge are in the range of 10,000 to the range of 10,000 to 30,000 AFY Each30,000 AFY Each

%Precip = R%Precip = RvvRRtt = R= Rvv + R+ Rll

Vertical RechargeVertical Recharge

Assume 4% Precipitation as Recharge Assume 4% Precipitation as Recharge 1.75 ft/yr (Precip) x 0.04 x 400,000 Acres = 28,000 AFY1.75 ft/yr (Precip) x 0.04 x 400,000 Acres = 28,000 AFY

Lateral RechargeLateral Recharge is Q=is Q=--KiAKiAAssume K =10 ft/Day, i = 0.003 and A = 4.5 X Assume K =10 ft/Day, i = 0.003 and A = 4.5 X 10106 6 ft (Perimeter of Upgradient edges of ft (Perimeter of Upgradient edges of Aquifer X 100’ thick)Aquifer X 100’ thick)

Q = 10 X 0.003 X 4.5 X 10Q = 10 X 0.003 X 4.5 X 106 6 = 11,340 AFY= 11,340 AFY

19501950 20002000

Water LevelsWater Levels

PumpingPumping

~30~30--40K AFY40K AFY

Evapotranspiration (ET)Evapotranspiration (ET)

• Refers to the Loss of Groundwater and Soil-moisture Due to Free-water Evaporation, Plant Transpiration or Soil-moisture Evaporation.

• Potential Evapotranspiration; “The Water Loss That Will Occur If at No Time There Is a Deficiency of Water in the Soil for Use by Vegetation” Thornthwaite,1955

• Actual Evapotranspiration, the Amount of ET That Occurs Under Field Conditions, Is Controlled by the Soil Moisture Content, Precipitation, Vegetation Density and Root Zone Depth

34

Applying ET in the Model AreaApplying ET in the Model Area• Crops will be main source of ET in the irrigated

areas• Recharge and ET the irrigated areas will be

coupled resulting in an effective recharge rate in those areas

• ET in riparian areas may be substantial• There is no readily available data for vegetation

in the riparian areas of the model• ET in the rest of the model area will be driven by

mesquite because it has a very high ET rate, a deep root zone depth and is prevalent outside the Lipan Flats

Evapotranspiration in Model AreaEvapotranspiration in Model Area

Data From Shirley Wade’s Preliminary Approach for Estimating Evapotranspiration

35

Rivers, Streams, Springs Rivers, Streams, Springs and Lakesand Lakes

USGS Stream GagesUSGS Stream Gages

Model boundary

36

Surface Water / Ground Water InteractionSurface Water / Ground Water Interaction

Mean Monthly River Gains From San Angelo to Paint Rock 1915 - 2000

19.325.5 23.1

50.6

112.9

64.6

39.3

14.9

102.2

78.5

25.620.4

0.0

20.0

40.0

60.0

80.0

100.0

120.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Riv

er G

ain,

cfs

Concho River Gains and LossesConcho River Gains and Losses

Concho River Gain or Loss Between San Angelo and Paint Rock by Decade

-2.06

3.00

8.49

5.47

2.29

6.31

16.72

19.58

23.53

-5

0

5

10

15

20

25

10's 20's 30's 40's 50's 60's 70's 80's 90's

Decade

Ave

rage

Mon

thly

Gai

n/Lo

ss (c

fs)

Loss to Aquifer

Gain from Aquifer

Lake Nasworthy Impounded 1930 O.C. Fisher

Impounded 1958

Twin ButtesImpounded 1963

Waste Water Treatment Plant

37

USGS GainUSGS Gain--Loss Study 1918Loss Study 1918

Source: Table 4, Gains and Losses from gain-loss studies in Texas

~ 3900 AFY~ 3900 AFYLake Lake Not PresentNot Present

Lake Lake Not PresentNot Present

Lake Lake Not PresentNot Present

USGS GainUSGS Gain--Loss Study 1925Loss Study 1925

Source: Table 4, Gains and Losses from gain-loss studies in Texas

Lake Lake Not PresentNot Present

Lake Lake Not PresentNot Present

~ 3800 AFY~ 3800 AFY

38

Modeling the StreamsModeling the Streams• Use MODFLOW stream routing package (STR)• This package routes the streamflow based on

stream geometry, roughness coefficient, and groundwater gains or losses

• Streams are divided into segments which, in this model, represent each creek or river

• Each cell of the model with the stream package in it is assigned a reach number.

• Streamflow in a segment is routed from the upstream reach to the next downstream reach

• Groundwater gains and losses are calculated based on the stage in each river reach

Assigning Stream PropertiesAssigning Stream Properties

• Stream properties are assigned using river reach files from the US EPA

• River reach GIS coverages are overlain on the model grid

• Measured versus calculated streamflow will be used as a calibration target at stream gage locations

39

Springs in Model AreaSprings in Model Area

Franklin T. Heitmuller and Brian D. Reece, 2003. U.S. Geological Survey (USGS) Open-File Report 03-xxxx, "Springs of Texas and springflow measurements".

Historical Spring Flow (gpm) in Model Area Historical Spring Flow (gpm) in Model Area

Franklin T. Heitmuller and Brian D. Reece, 2003. U.S. Geological Survey (USGS) Open-File Report 03-xxxx, "Springs of Texas and springflow measurements".

40

Hydraulic PropertiesHydraulic Properties

Specific-Capacity Data in TWDB Database

Model boundary

41

Estimating SpecificEstimating Specific--Capacity and Capacity and Transmissivity using Production CapacityTransmissivity using Production Capacity

Specific-Capacity from Production Capacity• Use Production Capacity (Q) and Saturated thickness in

Well (b)• Assume Specific-Capacity (Sc) = Q/b• Assume Q is in gallons per minute• Sc is in Gallons per minute per footTransmissivity from Specific-Capacity• Used “Estimating Transmissivity Using Specific-Capacity

Data” (Mace, 2000) Appendix A• Assumptions: 10 minute Pumping time, 8” Well Diameter,

Storativity (S) of 0.0001• Estimated Transmissivity Values range from 0.3 to 4000

ft2/day

Estimated SpecificEstimated Specific--Capacity Based on Capacity Based on Production CapacityProduction Capacity

Distribution of Specific Capacity

0

200

400

600

800

1000

1200

0 2 4 6 8 10 12 14 16 18 20Bin

Cou

nt

Distribution of Log of Specific Capacity

0

50

100

150

200

250

300

350

-3 -2.7 -2.3 -2 -1.7 -1.3 -1 -0.7 -0.3 0 0.33 0.66 1 1.33 1.66Bin

Cou

nt

42

Calculated Transmissivity Based on Production DataCalculated Transmissivity Based on Production Data1334 Data Point

Log Transmissivity-1

0

1

2

3 - 4

High Production Zone

(ft(ft2/day)/day)

DischargeDischarge

43

Groundwater Discharge 1974 & 1977Groundwater Discharge 1974 & 1977

Pre-1980 Groundwater Withdrawal

259

1185

9213

10657

17852330

10787

14902

300

1250

12500

14050

15072022

13551

17080

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

CONCHO RUNNELS TOM GREEN All

Acr

e Fe

et P

er Y

ear

1974 Irr

1974 Total

1977 Irr

1977 Total

Data Source: TWDB HistoricalSummary_1974and1977.xlsdata Location: [sburton] D:\Active_Projects\Lipan\LEON\srcdata\subhyd\irrigation\HistoricalSummary_1974and1977.xlsFile Location: [sburton] D:\Active_Projects\Lipan\LEON\srcdata\subhyd\irrigation\HistoricalSummary_1974and1977.xls

Irrigation Wells Installed Since 1950Irrigation Wells Installed Since 1950

0

500

1000

1500

2000

2500

1950

- 195

9

1960

- 196

9

1970

- 197

4

1975

- 197

9

1980

- 198

4

1985

- 198

9

1990

- 199

4

1995

- 199

9

2000

- 200

1

2002

+

Irrig

atio

n W

ells

Inst

alle

d

LKWCD Database TWDB Database

Combined Cumulative

44

Population Changes in Model AreaPopulation

County 1980 1990 2000

Concho 2,915 3,044 3,966Runnels 11,872 11,294 11,495Tom Green 84,784 98,458 104,010

1980-1990 1990-2000

Concho 129 922Runnels -578 201Tom Green 13,674 5,552

1980-1990 1990-2000

Concho 4.43 30.29Runnels -4.87 1.78Tom Green 16.13 5.64

Numerical Change

Percent Change

Water QualityWater Quality

45

Lipan Water QualityLipan Water Quality

TDS100 - 1000

1001 - 3000

3001 - 10000 0 7.5 15Miles

SteadySteady--State Calibration Model State Calibration Model ArchitectureArchitecture

46

USGS WaterLevel Contours

Study AreaStudy Area

Model DomainModel Domain

47

Model GridModel Grid

Boundary ConditionsBoundary Conditions

Gen

eral

Hea

d

General Head

No Flow

No Flow

General H

ead Boundary

48

1989 TWDB Irrigated Land Coverage1989 TWDB Irrigated Land Coverage

Pre-1980 Groundwater Withdrawal

259

1185

9213

10657

17852330

10787

14902

300

1250

12500

14050

15072022

13551

17080

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

CONCHO RUNNELS TOM GREEN All

Acr

e Fe

et P

er Y

ear

1974 Irr

1974 Total

1977 Irr

1977 Total

Data Source: TWDB HistoricalSummary_1974and1977.xlsdata Location: [sburton] D:\Active_Projects\Lipan\LEON\srcdata\subhyd\irrigation\HistoricalSummary_1974and1977.xlsFile Location: [sburton] D:\Active_Projects\Lipan\LEON\srcdata\subhyd\irrigation\HistoricalSummary_1974and1977.xls

Groundwater Discharge 1974 & 1977Groundwater Discharge 1974 & 1977

49

MethodologyMethodologyIrrigated Land

CoverageModel Grid

Overlay these Coverages

Result: Grid Coverage with Pumping Assigned to Cells Based on Volume of Cell Covered by Irrigated

Lands Coverage

Distribute County Wide Pumping Evenly Over Grid Cells with Irrigated Lands

Distribution of 1977 Irrigation Pumping Based on 1989 Irrigated Distribution of 1977 Irrigation Pumping Based on 1989 Irrigated Land CoverageLand Coverage

Irrigation Pumping ft3/day

50

51

52

53

Preliminary SteadyPreliminary Steady--State Model SimulationState Model Simulation

Green Lines Green Lines ––Published USGSPublished USGS

Water levelsWater levels

Blue Lines Blue Lines ––Model PredictedModel Predicted

Water LevelsWater Levels

Project ScheduleProject Schedule

Attendees of the 3rd

Stakeholder Advisory Forum for the Lipan GAM July 31, 2003

Name Affiliation James Beach LBG-Guyton Associates Richard Smith TWDB Scott McWilliams UCRA Bill Lange Lange Drilling Co. Allan Lange Lipan-Kickapoo WCD Will Wilde City of San Angelo Mr. and Mrs. E.R. Talley Talley Farms

Lipan Aquifer Groundwater Availability Model (GAM) 3rd Stakeholder Advisory Forum (SAF) Meeting

July 31, 2003 San Angelo, Texas

Meeting Summary The third Stakeholder Advisory Forum (SAF) meeting for the Lipan Aquifer Groundwater Availability Model (GAM) was held on July 31st from 7:00 to 8:30 PM at the Texas A&M Research Center in San Angelo, Texas. TWDB project manager Richard Smith gave an introduction to the GAM program and introduced LBG-Guyton Associates. James Beach of LBG-Guyton made a presentation to an audience consisting of five attendees. The presentation, along with a list of participants who signed up at the meeting, is available at the TWDB GAM website (www.twdb.state.tx.us/gam). The presentation was structured to cover all the components of the conceptual model and the data assimilated for the project. The questions and answers from the SAF are presented below. Questions and Answers Q: Why does the model simulate flow with one layer when we know that there are unique

zones in the limestone that are usually one to two feet thick that produce most of the water in the wells?

A: MODFLOW uses a continuous porous media conceptualization to simulate groundwater flow. This basically means that the aquifer material in each model layer is the same throughout the thickness of that model layer. To appropriately implement a model with many layers, we would need to know where each of the high permeability zones is located in each well, as well as how contiguous that zone is in the surrounding area. That level of information does not exist; therefore the aquifer has been conceptualized to contain one layer and that layer is assumed to represent the overall transmissivity of the aquifer. The transmissivity value in each model grid block represents the overall “productivity” of the aquifer in that area. This conceptualization is consistent with the overall GAM model objectives and the level of data that is available at this time. This approach has been used successfully to simulate overall ground-water availability in aquifers that have similar vertical variation in hydraulic properties.

Q: Some of the spring data is not consistent with current observations. When was the data

collected? A: The USGS compiled these data. The database does not indicate the date of observation

or the hydrologic conditions at the time.

Q: Groundwater pumpage for irrigation has occurred in the areas designated as areas where surface water is used. How will the model account for this?

A: We will discuss this issue with the TWDB and evaluate existing data regarding irrigation wells in these areas during the calibration and verification periods of the model (1980-2000) as well as predictive periods.

Q: Will the conceptual model report be released before the next SAF meeting? A: The draft report is for internal TWDB use and is intended as a means of insuring

that the model development remains on schedule. The report is generally not for public release; however, we will ask the TWDB to consider releasing the conceptual model report for review by stakeholders.