Wastewater Reuse: Benefits and Risk Assessment in Inland Bays Indian River Basin

The goal of this project is to develop a three-dimensional (3D) numerical groundwater flow model to evaluate the potential impacts to surface- and groundwater resulting from the disposal of treated wastewater in a portion of the Inland Bays drainage basin. The work will be accomplished with in-house software (ArcGIS, Surfer, and Visual MODFlow).

By developing a sub-regional, fresh, groundwater flow model and analyzing results, several issues will be addressed that are related to state policy, regulation revision, and proposed projects associated with land-based wastewater disposal (LBWD) in Sussex County.

1. Evaluate hydrologic effects of existing and proposed wastewater reuse and LBWD sites.
2. Simulate geochemical impacts of DNREC proposed wastewater treatment standards on groundwater quality.
3. Evaluate the benefits and risks to both groundwater and surface water from wastewater reuse and LBWD.
4. Develop and test methods to implement spatially detailed gridded and vector datasets in a Visual MODFlow environment that cannot accommodate the spatial detail.

The study area is bounded on the south by Indian River, on the north by Herring Creek, on the east by Rehoboth Bay, and the west by Cow Bridge Branch, in eastern Sussex County, with an approximate area of 64 mi². This area is of interest because it includes two existing large (> 1 MGD, Inland Bays and Mountaire) and one small (<50 KGD, Baywood Greens) spray irrigation facilities, and an existing large (>500 KGD), but underutilized (<20 KGD) rapid infiltration basin disposal site (Stonewater Creek). Water supply is largely served by individual domestic wells with additional spatially dispersed public and agricultural wells.