HYDROGEOLOGIC CONCEPTUAL MODELS

DEVELOPING, TESTING, AND COMMUNICATING

JOHN LAMBIE, PG, PE, HYDROGEOLOGIST (E-PUR)

DR. MATTHEW TONKIN, HYDROGEOLOGIST (S.S. PAPADOPULOS & ASSOCIATES)

SHAY OVERTON, PG, CHG, HYDROGEOLOGIST (PROVOST & PRITCHARD)

OBJECTIVES FOR THE PRESENTATION

• DEMONSTRATE THE IMPORTANCE OF THE HYDROGEOLOGIC CONCEPTUAL MODEL (HCM) TO UNDERSTANDING DATA

• INITIATE A DIALOGUE AMONG THOSE WORKING WITH THE SGMA ON A COMMON FRAMEWORK OF PRACTICES FOR DEVELOPING AND COMMUNICATING HCM(S)

• CONNECT THE USE OF HCMS TO PLANNING METRICS SUCH AS MEASURABLE OBJECTIVES AND MINIMUM THRESHOLDS IN THE SGMA

WHY BUILD A HYDROGEOLOGIC CONCEPTUAL MODEL?

• AS A FRAMEWORK FOR UNDERSTANDING THE SYSTEM OF SURFACE TO SUBSURFACE MOVEMENT OF WATER

• AS A FRAMEWORK FOR UNDERSTANDING RELATIONSHIPS AMONG GROUNDWATER HYDRAULIC HEADS

• IT LIES AT THE ROOT OF ANY QUANTITATIVE ANALYSIS OF WATER UNDER THE SGMA

WHAT IS A HYDROGEOLOGIC CONCEPTUAL MODEL?

• IT’S ALL ABOUT THE RELATIONSHIPS AMONG THINGS THAT AFFECT MOVEMENT OF WATER • TOPOGRAPHY

• HYDRAULIC HEAD (PRESSURE)

• HYDROSTRATIGRAPHY

HYDROGEOLOGIC CONCEPTUAL MODEL – FORMS AND FORMATS• ALL SORTS OF GRAPHICAL AND TABULAR FORMS

HYDROGEOLOGIC CONCEPTUAL MODEL – FORMS AND FORMATS• ALL SORTS OF GRAPHICAL AND TABULAR FORMS

THOUGHTS FOR BEST PRACTICES IN HCM DEVELOPMENT

• INITIAL REVIEW OF GEOLOGY • SOURCES AND TYPES OF DATA

• GEOLOGIC MAPS

• WELL LOGS

• E-LOGS

• FIELD OBSERVATIONS – PICTURES AND ROCKS!

• INITIAL REVIEW OF HYDROLOGY • LONG TERM MONITORING (LTM) DATA

• GROUNDWATER

• PRECIPITATION MODELS SUCH AS PRISM

• STREAM GAGES

• WET SEASON FLOW

• STREAM BASE FLOW AND BASE FLOW RECESSION

FURTHER ON HCM DEVELOPMENT -SECONDARY REVIEW OF GEOLOGY • GEOLOGIC STRUCTURAL ANALYSIS

FURTHER ON HCM DEVELOPMENT -SECONDARY REVIEW OF GEOLOGY

• SEDIMENT TEXTURAL ANALYSIS

FURTHER CONCEPTS OF BEST PRACTICES FOR HCM DEVELOPMENT

SECONDARY REVIEW OF HYDROLOGY • LAND USE IMPACTS TO HCM FOR WATER MOVEMENT

• AGRICULTURAL FOOTPRINTS ON WATER

• CANAL LEAKAGE EFFECTS

• CONSERVATION EFFECTS

• WATER IMPORT EFFECTS

• URBAN FOOTPRINTS ON WATER

• CORRELATION ANALYSIS OF LONG-TERM MONITORING DATA (LTM)

GROUNDWATER RESPONSE ANALYSIS OF LONG TERM MONITORING (LTM)

• OBJECTIVE ANALYSIS OF LTM DATA OVER TIME AND SPACE

• THE EVALUATION OF WATER LEVEL, PUMPING AND OTHER DATA IS ESSENTIALLY PATTERN-RECOGNITION TO IDENTIFY:• LARGE-SCALE PATTERNS DUE TO LARGE-SCALE INFLUENCES

• LOCAL-SCALE DEVIATIONS FROM THESE LARGE PATTERNS

• DOING SO CAN ENABLE BETTER DEFINITION OF UNDERLYING SPATIAL AND TEMPORAL TRENDS, INCLUDING CLUSTERING OF WELLS TO SYSTEM STRESSES (E.G. RECHARGE AND EXTRACTION)

RECHARGE BASIN RESPONSE CLUSTER

12

• MEMBERSHIP SHOWN AT LEFT

• TIGHTLY-SPACED CLUSTER NEAR BASINS

• RECHARGE RESPONSE LEVELS OFF

THOUGHTS ON HCM TESTING

• TEST AGAINST THE DATA YOU HAVE

• ENABLES A CHECK ON WHETHER THE DATA CONSTRAIN THE FUNDAMENTAL RELATIONSHIPS OF WATER MOVEMENT IN THE HCM

• INFORMATION ABOUT THE HYDROSTRATIGRAPHY MAY OR MAY NOT BE VALIDATED BY LTM DATA – IDENTIFY ESSENTIAL DATA GAPS

• COLLECT ADDITIONAL DATA TO FILL DATA GAPS

• DO THOSE DATA CONFIRM, REFUTE OR INFORM THE HCM?

• NUMERICAL MODELING

HCM IN NUMERIC FORM

Model Framework Visualization from Groundwater Desktopwww.groundwaterdesktop.com

AQUIFER UNIT WATER STORAGE ESTIMATES

Unconfined Specific Yield ~ 1% to 20%

Confined Unit(s) Storage ~0.01% to 0.1%

DATA ARE NEEDED TO CONSTRAINESTIMATES

HYDROGEOLOGIC CONCEPTUAL MODEL CONFINED ZONE PUMPING RESPONSE

Aquifer Flexing

Aquifer Flexing

HCM(S) AND THE SGMA

• AN HCM THAT INCORPORATES THE FACTORS AND PHYSICS ENABLES A BETTER UNDERSTANDING OF OUTCOMES

• OUTCOMES IN THE DATA ARE AT THE CORE OF THE SGMA AND UNDERSTANDING THE SIGNIFICANCE OF THOSE

MEASURED GROUNDWATER HEADS IN NESTED WELLS

59-68’

220-240’

360-380’

520-540’

860-880’

210-230’

410-430’

560-580’

200-220’

280-300’

615-635’

520-540’

Not to Scale

HCM(S) AND SGMA

• SGMA IS ABOUT PROJECTED OUTCOMES AND ACTUAL OUTCOMES

• WELL ESTABLISHED HCMS ARE NEEDED THAT ACCOUNT FOR SYSTEM DYNAMICS

• TO UNDERSTAND CURRENT DATA

• AND TO PROJECT FUTURE OUTCOMES

• DISCUSSION AND DIALOGUE ON BEST WAYS TO DEVELOP AND CONFIRM HCM(S)

QUESTIONS?jlambie@e-purwater.com

(209) 451-5933