Arc Hydro Groundwater Data Model

Gil Strassberg[1], David R. Maidment[2] and Norman L. Jones [3]

Table of Contents

 

Introduction

In 2002, the Arc Hydro data model was published by ESRI Press. Since its publication the data model has been adopted by a wide range of organizations as a standardized format for archiving and distributing water resources data. Arc Hydro is one of a number of data models developed for users of ArcGIS. Such models include transportation, geology, marine, petroleum, water utilities, and others, describing a variety of disciplines that utilize GIS technology (ESRI, 2005). The purpose of these models is to develop a set of “best practices” geodatabase designs to help users implement GIS in a productive manner and to share information within user communities (Arctur et al, 2004). Arc Hydro is a data base design for storing hydrologic geospatial and temporal information within a geographic information system. The database and accompanying toolset operate within the ArcGIS environment and are public domain. Originally, the data model focused on surface water data, but it became apparent that a similar model is needed for storing and sharing groundwater information.

Figure 1. The four components of the Arc Hydro framework for surface water

Data model objectives

The following objectives were defined to guide the data model design:

  1. The data model should support representation of both regional and site-scale groundwater systems.
  2. The data model should enable the integration of surface and groundwater information (through the integration with the surface water component).
  3. The data model should facilitate the extraction of archived groundwater data for use with groundwater modeling software. And will support the storage and display of solutions computed by groundwater models.

Data model design

Rather than trying to anticipate all the different types of groundwater data that can potentially be stored in a geodatabase, the focus was set on describing ground water information in terms of raw field data and conceptual representations of the primary features in a hydrogeologic system. This allows the data model to be used as a tool for archiving and sharing groundwater data for a wide variety of applications. The importance of 3 dimensional GIS in the characterization of the subsurface has been widely emphasized (Bohman-Carter, 2000; Moore et al, 1993; Turner, 1989 and 2000). An effort was made to include three dimensional features (i.e. solids, cross sections) as much as possible to reflect the nature of hydrogeologic systems.

The data model framework, shown in Figure 2, outlines four subgroups of information arranged into feature datasets and raster catalogs. These include Hydrogeology, Modeling, GeoRasters, and Raster Series. The Hydrogeologic unit table links spatial representations of the same geologic unit together and stores the properties of the unit. In addition to the spatial features the data model will represent temporal information using the time series component of the Arc Hydro model.

Figure 2. Arc Hydro groundwater data model framework

The Hydrogeology feature dataset, Figure 3, is a set of vector classes that describe the hydrogeology of an aquifer system. The dataset includes representations of two dimensional features such as wells and aquifer outlines, as well as three dimensional classes to describe hydrostratigraphy, solid volumes, and cross sections.

 

Figure 3. Hydrogeology feature dataset

 

The modeling feature dataset, Figure 4, is a set of vector features that represent common modeling objects. These feature classes can represent computational grids such as finite difference grids and finite element meshes, and enable storage and presentation of model inputs and outputs. The modeling feature dataset includes four feature classes: Boundary, Cell2D, Cell3D, and Nodes.

 

Figure 4. Modeling feature dataset

 

GeoRasters and Raster series, Figure 5, are collections of raster datasets stored in raster catalogs. GeoRasters define boundaries of units by describing the unit’s top and bottom elevations or distributions of properties, such as hydraulic conductivity, transmissivity, and porosity, within the unit. Raster series represent parameters related to the water within a hydrogeologic unit, such as contaminant concentrations over time or the change of a potentiometric surface within an aquifer.

 

Figure 5. GeoRasters and Raster Series

 

The collaborators are currently working to materialize the presented concepts into a functional database and toolset. We welcome any individual or organization who wishes to contribute to the data model development to contact the authors.

 

Tools

Arc Hydro groundwater tools:

Many of the features in the data model have three dimensional geometries, which makes it difficult for users to create and edit. A set of tools to help users populate the data model objects is under development at the Center for Research in Water Resources.

Figure 6. Arc Hydro Groundwater toolbar

 

To download the toolbar and an exercise from Dr. Maidment’s class refer to:

http://www.ce.utexas.edu/prof/maidment/giswr2004/ex6/Ex62004.htm

Newer versions of the tools will be posted on the ESRI and CRWR websites as development continues.

 

MODFLOW tools:

To help integrate the data model with MODFLOW a set of geoprocessing tools were developed to demonstrate how the data model structure can be linked to models. The toolbox developed includes a set of tools to create the features needed for storing input and outputs of a MODFLOW model and to help users view the modeling results within ArcGIS. To download the toolbox and an exercise see Dr. Maidment’s class at:

http://www.ce.utexas.edu/prof/maidment/gradhydro2005/groundwater/BartonSprings.htm

 

Downloads

References

  • Arctur, D., Zeiler, M. (2004). Designing Geodatabase Case Studies in GIS Data Modeling. ESRI Press.

  • Bohman-Carter, G. (2000). An Overview of GIS in the Geoscience. Geographic information systems in petroleum exploration and development  AAPG computer applications in geology ; no. 4. T. C. Coburn and J. M. Yarus. Tulsa, Okla., American Association of Petroleum Geologists: xii, 315.

  • ESRI, website. (2005). http://support.esri.com/datamodels

  • Moore, I. D., A. K. Turner, et al. (1993). GIS and Land-Surface-Subsurface Process Modeling. Environmental modeling with GIS. M. F. Goodchild, B. O. Parks and L. T. Steyaert. New York, Oxford University Press: xxiii, 488 , [8] of col. plates.

  • Turner, A. K. (1989). The role of three-dimensional geographic information systems in subsurface characterization for hydrogeological applications. Three dimensional applications in geographical information systems. J. Raper. London ; New York, Taylor & Francis: ix, 189 , [8] of plates.

  • Turner, A. K. (2000). Geoscientific Modeling: Past, Present, and Future. Geographic information systems in petroleum exploration and development  AAPG computer applications in geology ; no. 4. T. C. Coburn and J. M. Yarus. Tulsa, Okla., American Association of Petroleum Geologists: xii, 315.


[1] Research Assistant, Center for Research in Water Resources, University of Texas at Austin, 512-471-0110 (gilstras@mail.utexas.edu)

[2] Director, Center for Research in Water Resources, University of Texas at Austin, 512-471-4620,  (maidment@mail.utexas.edu)

[3] Director, Environmental Modeling Research Laboratory, Brigham Young University, 801-422-7569 (njones@byu.edu)