Research use only—not for engineering design or site-specific decisions. Envision Water created this viewer, not the original groundwater model. Data and results require independent verification. Full disclaimer
EXPLORE THE MODEL
Aquifers in context View 3D view Plan view
Aquifer unitAll units in selected layer Result layer CountyEntire model Groundwater districtAll districts About these controls Area filters use TWDB grid assignments. Results refer to the selected aquifer and model layer.
Results DisplayAquifer framework Requested pumping · AF/year per cell Simulated head elevation Saturated thickness Depth to simulated head Head decline from baseline Saturated thickness loss (ft) Saturated thickness loss (%) Horizontal conductivity Vertical conductivity Specific yield Specific storage Drawdown baseline1929 · steady state 2012 · end of original calibration 2020 · final historical year 1929 → 2020 decline map Saturated thickness loss
Select year and animate using the timeline below the map.
Load a head time series MODFLOW binary heads (.hds) Single- or double-precision MODFLOW heads on the HPAS 932 × 580 grid. Files are read locally in your browser. The selected layer is loaded on demand.
Use TWDB historical sequence
Overlays Analysis Appearance TWDB model & documentation ↗ Aquifer framework Four model layers · Native half-mile cells
Loading actual TWDB model data…
⌂ N ↑
Drag to rotate · Right-drag / Shift-drag to pan · Scroll to zoom · Click to inspect
‹ Insight Cross-section Native cell geometry · elevations in feet
Export section Close × DATA & INTERPRETATION
High Plains Aquifer System Groundwater Availability Model Actual TWDB version 1.02 model geometry, hydraulic properties, and grid assignments. The historical model includes 1929 steady state and annual periods through 2020. The supplied predictive model covers 2021–2080. The original model was calibrated through 2012; the 2013–2020 extension was not recalibrated.
Built-in results: historical simulated heads extracted from TWDB’s hpas_v102_heads.csv in the v1.02 GAM Properties archive, aligned by layer, row, and column. The predictive BAS starting heads independently confirm the final historical snapshot. The GAM Properties archive supplies a historical head sequence as CSV/GeoPackage, with 92 stress periods from 1929 steady state through 2020. This sequence is included for animation and hydrographs. Imported binary heads remain available for separate scenarios.
Units: elevations and distances in feet, conductivity in ft/day, specific storage in 1/ft, and specific yield dimensionless. Coordinates use TWDB GAM Albers / NAD83 / US survey feet. Vertical datum should be confirmed against project documentation before combining external elevations.
Head surfaces average adjoining valid cell values for display. Interpolation is limited to valid cells; dry, dewatered, and inactive cells are omitted. Cell inspection and CSV export retain native cell values. Confined-layer heads represent hydraulic pressure expressed as elevation.
Saturated thickness = max(0, min(head, layer top) − layer bottom). This is a geometric result, not an estimate of recoverable water or well yield. Values above layer top indicate full saturation.
Named aquifers: Ogallala/Pecos Valley share L1; Rita Blanca and both Edwards–Trinity units share L2; upper and lower Dockum have separate layers. Display subsets use TWDB aquifer boundaries and HPAS grid assignments, not independently simulated fields for units sharing a layer.
Public observations: TWDB GWDB download, retrieved October 10, 2026. Publishable October–April measurements from 1930–2020, excluding pumping/dry/obstructed remarks; averaged by well and calendar year. Simulated heads are interpolated between annual end heads at mean measurement date. Single-aquifer assignments are checked against model activity and available screen intersections. Ambiguous/multi-unit completions are excluded; total-depth Dockum inferences are optional. This screening comparison does not reproduce official calibration statistics.
County and district filters use grid assignments rather than intersected administrative polygons. No DFC compliance calculation is implied.
2025 numerical extension report ↗ · TWDB source files ↗
× OBSERVED & SIMULATED
Public water-level comparison
Residual = observed − simulated. Positive means the simulation is too low. Annual winter-season means receive equal weight per well-year. These public wells may overlap calibration targets, so this is not an independent validation.
The published water-level elevations retain their source elevation reference. No vertical datum correction has been applied. Comparisons use the containing half-mile cell and annual temporal interpolation, rather than the report’s MOD2OBS method.
TWDB public data source ↗ × MEASURED & MODELED HISTORY
Historical hydrograph
Export hydrograph Export observed / simulated history × PUBLISHED MODFLOW WATER BUDGETS
Water budget review Aquifer ScopeTexas aquifer footprint County Groundwater district Area Aquifer footprint Budget year
Export budget and calculations TWDB report source ↗ × REQUESTED MODEL PUMPING
Spatial & temporal pumping review
Negative WEL rates are aggregated to native cells and converted using each DIS stress-period duration. These are requested model inputs, not simulated withdrawals after pumping reductions. The 1929 steady-state period is not an annual pumping estimate.
Export annual pumping Export displayed pumping cells × Sources & references Model: High Plains Aquifer System Groundwater Availability Model v1.02. Bundled datasets retrieved October 10, 2026.
Historical heads: GAM Properties hpas_v102_heads.csv. Pumping: historical WEL inputs. Budgets: extension report Tables 5-6–5-9 and Appendices C–D. Texas wells, water levels and chemistry: GWDB. Surrounding-state wells: extension geodatabase ext_well_points. DFC cards link to their individual sources.
Independent Envision Water viewer of published TWDB data. No TWDB endorsement is implied.
× TWDB MEASURED GEOCHEMISTRY
Well chemistry
Sample Sampling source & reliability
Selected parameter history Trend includes only numeric results without qualifiers. Detection limits and other qualified results remain in the sample table and CSV. Parameter codes, units and fractions are retained; no groundwater chemistry is simulated by HPAS.
Export sample chemistry TWDB source ↗ × Research Use Disclaimer Envision Water developed this visualization interface but did not develop the original High Plains Aquifer System Groundwater Availability Model or the underlying source datasets. Model files, results, and supporting data were obtained from the Texas Water Development Board and other identified sources. This viewer is an independent application; no endorsement by the original model developers or data providers is implied.
The viewer is provided for research, education, and exploratory visualization only. It is not intended for engineering design, permitting, regulatory determinations, or site-specific decisions. Regional model results do not establish conditions or predict impacts at an individual well or property.
Displayed information may contain errors, omissions, outdated records, or limitations introduced by source data, model assumptions, processing, or visualization. Users are responsible for verifying information against original documentation and obtaining appropriate professional evaluation before relying on it.
The viewer and its contents are provided “as is,” without warranties of accuracy, completeness, reliability, or fitness for a particular purpose. To the fullest extent permitted by applicable law, Envision Water disclaims liability for losses, damages, or claims arising from use of, reliance on, or inability to use this viewer.
