of hydrologic systems (the framework data model
and the components are described in chapter 2).
We refer to the groundwater components of the
data model as Arc Hydro Groundwater, or simply
as the groundwater data model, which is the focus
of Arc Hydro Groundwater: GIS for Hydrogeology.
Arc Hydro is not just a set of data models. Rich
sets of tools have been developed to help ArcGIS
users implement the data model, organize their
data, and create GIS products. These tools make
use of the standard data structures and the relationships
between features within the data model
to enhance the capabilities of ArcGIS for the management
and analysis of water resources. For
surface water analysis, a set of tools named Arc
Hydro Tools has been developed by Esri. These
tools are available on the Esri Web site (www.esri.
com/archydro). For groundwater analysis a set of