GIS and Water Sustainability – A Taunton River Basin Case Study

Water is not always available in the quantity, quality, and location needed.  Treatment and transport technologies have enabled population growth in areas of scarce or limited water resources, often at the expense of sustainability.  To accommodate existing and future needs, local and state entities are seeking to keep water local by balancing water output (withdrawals) and input (precipitation, recharge) from a watershed.  Spreadsheet-style water budget modeling has enabled water availability evaluations at the local or watershed level, but the integration of geographic information and the automation of GIS tools furthers the capability across larger resource regions, such as entire river basins.  GIS modeling provides an opportunity to plan future development and water withdrawals and discharges in a more sustainable manner.

The Taunton River is the longest un-dammed coastal river in New England and the second largest watershed in Massachusetts with a watershed area covering approximately 562 square miles.  Its basin contains 108 sub-watersheds and encompasses all or part of 43 municipalities.  A water balance GIS model was developed for the Taunton River watershed to evaluate existing and future hydrologic impacts associated with water supply withdrawals, wastewater discharges, and stormwater runoff.  The model processes data including geology, land use, impervious cover, ground and surface water withdrawal and discharge locations and volumes, population density, sewer and water service areas.  Model verification was conducted by comparing modeled and existing baseflow estimates for streams in two sub-watersheds using available stream gauge measurements and precipitation records. 

This automated model combines state and local GIS data layers with other water resource information to compare pre- and post-development water balances at the sub-watershed level.  GIS data processing automation through modeling can then enable the evaluation of multiple development scenarios across all 108 sub-watersheds, and the optimization of future water withdrawals and discharges to keep water local.