th Stakeholder Advisory Forum West Texas Igneous and

1

55thth Stakeholder Advisory Forum Stakeholder Advisory Forum West Texas Igneous and Bolson GAMWest Texas Igneous and Bolson GAM

March 25, 2004March 25, 2004

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

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TAYLOR

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D E WITT

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MEN AR D

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PAR MER

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GR IMES

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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 Manager

• Texas 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 itself– 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 info

• 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– Deadline for comments on the IBGAM is April 9, 2004.

The final draft report is posted at:http://www.twdb.state.tx.us/gam/bol_ig/bol_ig.htm

• Contact TWDB (Robert Mace or Ted Angle)

Participating inParticipating inthe GAM processthe GAM process

6

Comments:Comments:Ted AngleTed Angle

(512)936(512)[email protected]@twdb.state.tx.us

www.twdb.state.tx.us/gamwww.twdb.state.tx.us/gam

Conceptual model Conceptual model

7

Conceptual Block DiagramConceptual Block Diagram

Bolsons

No Flow Boundary

Recharge

PumpingGroundwater-Surface Water Interaction Spring flow

Igneous

Cro

ss-fo

rmat

iona

l Flo

w

Cro

ss-fo

rmat

iona

l Flo

w

Cretaceous-Permian

Evapotranspiration

Recharge

Responses to Public Comments regarding Responses to Public Comments regarding Conceptual ModelConceptual Model

• Wells in the flats may be completed in both Bolson and igneous aquifers.

• Volcaniclastic units were included in the Bolson aquifer thickness because these units are unconsolidated, and have hydraulic conductivity more similar to Bolson than the igneous.

• Zonation - Although there are three layers in the model, aerial zonation was used to further refine hydraulic properties based on geology, hydraulic conductivity data, and water level responses.

• Hydraulic conductivity refers to the ability of an aquifer material to transmit water.

• Water level maps were developed according to the methodology in Appendix A, which relied on water levels measured around 2000. Apparent water level decreases between 1950 and 1980 were caused by differences in the contour interval on those maps.

8

Simulation PeriodsSimulation Periods

1990 – 2000: verification periodRelatively dry period

1950 – 1990: calibration periodFocus on 1970-1990Most significant irrigation pumping

pre-1950: steady state periodprior to major pumping

Time Period Length (years)

# Stress Periods

110

140

27381

GAM Modeling PeriodsGAM Modeling Periods

Steady-state

period

Calibration Verification Prediction

Wat

er E

leva

tion

in W

ell

1950 1990 2000 2050

Observed Water LevelModel Water Level

Pre-Development

Time

9

Total PumpingTotal Pumping

Pumping by AquiferPumping by Aquifer

10

Pumping (by County)Pumping (by County)

Model ArchitectureModel Architecture

11

Layer 1 Layer 1 Boundary Boundary

ConditionsConditions

Alluvial Fan

Recharge

Drain

Drain


ConditionsConditions

Drains in

Streams

Recharge

No-Flow

No-Flow

ET

No-

Flow

No-Flow

12


ConditionsConditionsGHB

GH

B

GHB

GHB

GHB

GH

B

Calibration and Calibration and VerificationVerification

13

EvapotranspirationEvapotranspiration

• 10 in/year maximum• Extinction depth= 10 ft

Transient Recharge FactorBased on Mt. Locke Precipitation Variation

14

Final Distribution of Steady-State

Recharge

(60% of Original Runoff Redistribution

Estimate)

Hydraulic PropertiesHydraulic Properties

3e-50.010.0001 - 0.10.1 - 13

3e-50.010.00008 - 0.10.2 - 12

-0.060.0001 - 0.354 - 501

storativityspecificyield

Kz(ft/day)

Kx(ft/day)

Layer

15

Horizontal Hydraulic Horizontal Hydraulic Conductivity (layer 1)Conductivity (layer 1)

Vertical Hydraulic Vertical Hydraulic Conductivity (layer 1)Conductivity (layer 1)

16



17



18

Responses to Public Comments regarding Responses to Public Comments regarding Model CalibrationModel Calibration

• Igneous hydraulic conductivity - Vertical variation in hydraulic conductivity within the igneous aquifer below the Bolsons is dealt with by assuming that the volcaniclastics are a part of the Bolson layer. In areas where the igneous units outcrop, it is assumed that the entire thickness of the igneous can be appropriately simulated with one layer. Any vertical variation in hydraulic conductivity is averaged over the layer (about 40 layers as 1). Horizontal permeability in the Igneous aquifer is 200-250 times greater than vertical hydraulic conductivity. This isappropriate because of the lack of vertical connection between layers of igneous deposits.

• Recharge - The general applicability of the runoff-redistribution method is based on other modeling studies that have been completed in the southwest and documented in the literature. Consistent with these publications, the estimated recharge was reduced to 60% of the original value determined from the method.

• Historical Pumping - On average, about 81% of groundwater use is for irrigation between the 1980-2000. However, the area and volume of groundwater used for irrigation did change between 1980 and 2000.

Calibration TargetsCalibration Targets

000Cretaceous

1670161654Total

423 *

1193

Calibration & Verification

4241Igneous

124653BolsonTotalSteady-stateLayer

•1670 head measurements in 365 wells

* - Included 245 geographically distributed measurements from 2000-2001

19

Calibration StatisticsCalibration StatisticsSteadySteady--State (1950)State (1950)

54

0

1

53

Count

(feet)(feet)(feet)

21

-

-

21

Residual Standard

Deviation (RMS)

---Cretaceous

0.03176All Layers

7

17

Mean Absolute

Error

-7Igneous

0.036Bolson

RMS/ RangeMean Error

Layer

Crossplot of SteadyCrossplot of Steady--State HeadsState Heads

20

1950 1950 Simulated Simulated

HeadsHeads(layer 1)(layer 1)



21



SteadySteady--State Volume Budget State Volume Budget (layer 1)(layer 1)

22



23

Calibration Calibration WellsWells

Calibration Statistics(1951(1951--1990)1990)

1017

0

122

895

Count

(feet)(feet)(feet)

34

-

35

35

Residual Standard

Deviation (RMS)

---Cretaceous

0.02287All Layers

35

27

Mean Absolute

Error

0.0317Igneous

0.04-10Bolson


Layer

24

Crossplot of heads during calibration period (1950Crossplot of heads during calibration period (1950--1990)1990)

Verification StatisticsVerification Statistics(1991(1991--2000)2000)

599

301

298

Count

(feet)(feet)(feet)

109

-

150

35

Residual Standard

Deviation (RMS)

---Cretaceous

0.0464-15All Layers

105

27

Mean Absolute

Error

0.05-15Igneous

0.05-15Bolson


Layer

25

Crossplot of heads during verification period (1990Crossplot of heads during verification period (1990--2000)2000)

1990 and 2000 Simulated Heads (layer 1)1990 and 2000 Simulated Heads (layer 1)

26



27

Simulated Simulated SteadySteady--State State

Evapotranspiration Evapotranspiration from Water Tablefrom Water Table

Volumetric Budget Volumetric Budget (layer 1)(layer 1)

28



29

Eastward Flow out of Wild Horse AreaEastward Flow out of Wild Horse Area

• In Bolson -flow drops from about 2,100 to zero AFY between 1950-1975

• In Cretaceous – flow drops from about 14,000 to 12,000 AFY between 1950-2000

HydrographsHydrographsMichigan FlatMichigan Flat

30

HydrographsHydrographsWild Horse FlatWild Horse Flat

HydrographsHydrographsWild Horse FlatWild Horse Flat

31

HydrographsHydrographsLobo FlatLobo Flat


32


HydrographsHydrographsRyan FlatRyan Flat

33

HydrographsHydrographsIgneous aquiferIgneous aquifer

HydrographsHydrographsIgneous aquiferIgneous aquifer

34

Water Level Water Level Change between Change between

1950 and 2000 1950 and 2000 (Layer 1)(Layer 1)



35



Observed and simulated drawdown (1950Observed and simulated drawdown (1950--2000)2000)

36

Crossplot of drawdowns (1950Crossplot of drawdowns (1950--2000)2000)

Sensitivity AnalysisSensitivity AnalysisSensitivity of Global Head (in 2000) to Global Parameter ChangeSensitivity of Global Head (in 2000) to Global Parameter Change

37

Sensitivity AnalysisSensitivity AnalysisSensitivity of Layer 1 (in 2000) to Global Parameter ChangeSensitivity of Layer 1 (in 2000) to Global Parameter Change


38


Sensitivity AnalysisSensitivity AnalysisHydrograph Sensitivity to Global Parameter ChangeHydrograph Sensitivity to Global Parameter Change

5110605 - Lobo Flat

39


5128607 - Ryan Flat


4759101- Wild Horse Flat

40

Predictive SimulationsPredictive Simulations

Responses to Public Comments regarding Responses to Public Comments regarding Model PredictionsModel Predictions

• Culberson Co. - In 2002, the State Water Plan included estimates of future demand in Culberson Co. that were about 1/3 of the current usage. Therefore, water levels generally increase in Culberson Co. during the predictive period. For the final report, another simulation will be completed which will include the recently approved demands from Region E, which are equal to the metered amounts.

• Region E strategy – a tentative strategy was approved by Region E and included in the State Water Plan (SWP) which proposed that El Paso would pump groundwater from Ryan Flat. The existing well field is located in Jeff Davis and Presidio Counties. However, the SWP stated that all the pumping would occur in Jeff Davis Co. Region E has approved a clarification of that strategy which assumes that pumping will occur in both counties, which better represents the intent of the strategy.

41

Total PumpingTotal Pumping

Pumping by CountyPumping by County

42

Drought of RecordDrought of Record

DOR: 1951-19577 years


43



DOR: 1951-19577 years

44


• DOR = 7 years

• 1951-1957

• Recharge estimates are based to variation in regional precipitation (average from gages in the model area)

• Ranges from 42-80% of normal and averages 64%

Water Level, Saturated Thickness and Drawdown Water Level, Saturated Thickness and Drawdown in 2010 in 2010 -- Average Recharge Average Recharge -- BolsonBolson

45

Water Level, Saturated Thickness and Drawdown Water Level, Saturated Thickness and Drawdown in 2010 in 2010 -- Average Recharge Average Recharge -- IgneousIgneous


46



47



48



49


Water Level, Saturated Thickness and Drawdown Water Level, Saturated Thickness and Drawdown in 2050 in 2050 -- Average Recharge Average Recharge –– Layer 3Layer 3

50

Difference in Heads in 2050 Difference in Heads in 2050 Average versus DORAverage versus DOR

Observed and Simulated Hydrographs (Average Recharge)Observed and Simulated Hydrographs (Average Recharge)

Well 4759101 – Wild Horse Flat

Well 5128607 – Ryan Flat

51

Model LimitationsModel Limitations

• Supporting Data– Igneous hydrogeology, hydraulic properties, fractures,

heterogeneity, connection to Bolson– Bolson pumping data

• Limiting Assumptions– Continuous porous media model– “Lumped-layer” conceptualization

• Limits of Applicability– Igneous simulations– Stream-aquifer interactions

ConclusionsConclusions

• Model meets GAM calibration/verification requirements

• Model is a good tool for RWP efforts• Good tool to assess regional Bolson drawdown

from proposed pumping• Probably not a good tool for detailed Igneous

evaluations

52

5th Stakeholder Advisory Forum

March 25th, 2004 West Texas Igneous and Bolson GAM

List of Attendees

Name Affiliation James Beach LBG-Guyton Associates John Ashworth LBG-Guyton Associates Zhuping Sheng TAMU Van Robinson self Bill Hutchison El Paso Water Utilities Steve Finch John Shomaker & Associates Dave Hall Public of El Paso Kevin Urbanczyk SRSU Janet Adams Jeff Davis UWCD Gorden Bell Guadalupe Mtns. N. Park Mike Mecke TAMU Extension Service James W. Word SRSU Robert R. Flores TWDB Pam Tarelle SWS Gordon Wells Freese & Nichols Simone Kiel Freese & Nichols Jeff Bennett National Park Service, Big Bend Juan D. Gomez CH2MHill

QUESTIONS AND ANSWERS West Texas Igneous and Bolson GAM

SAF Meeting 5 � March 25, 2004 Alpine, Texas

Question: Was the 60% recharge rate varied over the modeled area? Answer: No, the 60% rate was not varied spatially. Comment: You should discuss dispersion of horizontal hydraulic conductivity in Layer 2 as shown in Figure 4.2.7. Also explain that Ts are the factor that influences the model results. Answer: We recognize that the hydraulic conductivity numbers are different than those estimated from specific capacity and pumping tests. However, these values were necessary to maintain heads at the desired elevation. Question: Why doesn�t the decline in the Alpine well field show up earlier in time? Answer: The drawdown illustration starts in the base year 2000 and shows water level declines from that year forward. We will check what assumptions were made for that pumping demand for the final report. Question: Why do you simulate the Drought-of-Record only in the final decade? Answer: It was a requirement of the GAM process. Question: How did you distribute vertical pumpage in Ryan Flat? Answer: Projected demand for the Bolson aquifer is applied to Layer 1 only. Question: Can you ask for different input criteria when requesting a TWDB GAM run? Answer: Yes. Question: How quickly can we expect to get results back from a requested GAM run? Answer (Ted Angle): Model run requests will be processed in the order that they are received. Results should be available within approximately two weeks of date the run is initiated. NOTE: TWDB will send a letter of acknowledgement within two weeks of receipt of your request. TWDB staff should be able to complete requests within three months. However, estimated GAM run completion dates may be modified depending on priority requests.

Documents

th Stakeholder Advisory Forum West Texas Igneous and