1. Arc Hydro Groundwater Data Model
Gil Strassberg, David R. Maidment
Center for Research in Water Resources
University of Texas at Austin
Presented at American Geophysical Union, Fall Meeting
San Francisco, 9 December 2003
Hydrography
Hydro Network
Channel System
Drainage System
Hydrogeologic unit
Borehole
Well
Aquifer

2. GIS in Water Resources Consortium
CRWR
GIS
Water Resources
Bringing together these two communities by using a common geospatial data model
Arc Hydro design took 3 years from 1999 – Groundwater phase II

3. A model is a simplification of reality
Geographic Data Model
A model is a simplification of reality
Conceptual Model – a set of concepts that describe a subject and allow reasoning about it
Mathematical Model – a conceptual model expressed in equations
Data Model – a conceptual model expressed in a data structure
Geographic Data Model – a data model for describing and reasoning about the world

4. Hydrologic information system
A Synthesis of geospatial and temporal information that a which supports hydrologic analysis and modeling
Analysis, Modeling,
Decision Making
Arc Hydro
Geodatabase

5. Arc Hydro data model Time Series Hydrography Hydro Network
Flow
Time
Time Series
Hydrography
Hydro Network
Channel System
Drainage System

6. Arc Hydro groundwater data model
Temporal
Time
Time Series
Surface water
Groundwater
Drainage System
Hydro Network
Well
Aquifer
Hydrography
Channel System
Hydrogeologic unit
Borehole

7. Data model design process
Empty Geodatabase
UML Design
Table structures and relationships
Structured data
Site data
Filled geodatabase

8. ArcGIS features
GIS uses features and tables to describe a simplification of a “system” in this case the hydrological description.
3D features: 3D points, 3D lines and 3D polygons
2D features: Points, lines and polygons
Points - Wells
Polygons - Aquifers
3D points
Lines-
River network
3D lines -Wells
Geodatabase
Tables with information
Time series
3D polygons

9. 3 Dimensional representation
Describing aquifer architecture, hydrogeologic
parameters and related temporal data
Temporal data
Savannah River Site

10. Interfacing with the data model
Data model geodatabase
Custom tools
A database that matches information required to execute a specific model (e.g. MODFLOW)
Models
Model interface
Simulation Models

11. Example of Savannah River Site
MODPATH simulation
MODFLOW model for Savanna River Site

12. Example of MODPATH
GIS has built in tools for tracking over time and space
Tracking analyst

13. Interfacing surface and groundwater models
Arc Hydro data model
Surface water models
Groundwater models
Simulated results
Simulated results

14. Integrated simulation
Groundwater simulation
Surface water
simulation

15. Key points
Arc Hydro is a geographic data model – basis for hydrological information system
Extended to include the main features of groundwater systems
Provide a data interface between ArcGIS and commonly used groundwater modeling programs
Integration of models through the data model.

16. Questions? For more information:
Gil Strassberg:
David Maidment: