Incorporating Stream Features into Groundwater Contouring Tools Within GIS

Area of Science:

• Hydrogeology
• Geographic Information Systems (GIS)
• Surface Water-Groundwater Interaction

Background:

• Hydrogeologists estimate water table surfaces from sparse data, often manually.
• Traditional geographic information systems (GIS) create smooth surfaces but lack hydrogeologic context.
• Automated GIS methods often fail to incorporate influences on the water table.

Purpose of the Study:

• To develop an interactive GIS-based tool for hydrogeologists.
• To integrate knowledge of gaining or losing streams into water table surface interpolation.
• To improve the accuracy and utility of digital water table models.

Main Methods:

• Developed an interactive tool within Esri's ArcGIS Desktop software.
• The tool modifies interpolated surfaces based on stream-aquifer interactions.
• User-defined adjustments create "V"-shaped contours for gaining streams, reflecting hydrogeologic knowledge.

Main Results:

• The tool successfully shapes interpolated water table surfaces based on stream influences.
• Modified surfaces generate contours that accurately reflect hydrogeologic features.
• The approach allows for interactive adjustments to better match user expectations.

Conclusions:

• This tool bridges the gap between automated GIS interpolation and hydrogeologic expertise.
• It provides a prototype for incorporating various hydrogeologic features into surface modeling.
• Enhanced water table surface models can improve subsequent analyses like gradient and flow path calculations.