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

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 – 2002. Groundwater phase II 2002 - 2005.

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

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

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

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

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

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

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

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

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

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

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

Integrated simulation Groundwater simulation Surface water simulation

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.

Questions? For more information: Gil Strassberg: gilstras@mail.utexas.edu David Maidment: maidment@mail.utexas.edu