A rapid infiltration basin system (RIBS) consists of several simple and relatively standard technologies; collection and conveyance of wastewater, treatment, and discharge to an unlined excavated or constructed basin. By design, the effluent quickly infiltrates through the unsaturated or vadose zone to the water table. During infiltration, some contaminants may be treated by biological and/or geochemical processes and diluted by dispersion and diffusion.
The hydrogeologic framework of Cape Henlopen State Park (CHSP), Delaware was characterized to document the hydrologic effects of treated wastewater disposal on a rapid infiltration basin system (RIBS). Characterization efforts included installation of test borings and monitoring wells; collection of core samples, geophysical logs, hydraulic test data, groundwater levels and temperatures; testing of grain size distribution; and interpretation of stratigraphic lithofacies, hydraulic test data, groundwater levels, and temperature data.
The Delaware Geological Survey (DGS) has released a new technical report titled Simulation of Groundwater Flow and Contaminant Transport in Eastern Sussex County, Delaware with Emphasis on Impacts of Spray Irrigation of Treated Wastewater, which was prepared by Changming He and A. Scott Andres of DGS.
DGS Report of Investigations No. 79 documents development of a detailed study of subsurface hydrogeology, interactions between aquifers and streams, and the effects of spray irrigation of treated wastewater on groundwater beneath southern eastern Sussex County.
This report presents a conceptual model of groundwater flow and the effects of nitrate (NO3-) loading and transport on shallow groundwater quality in a portion of the Indian River watershed, eastern Sussex County, Delaware. Three-dimensional, numerical simulations of groundwater flow, particle tracking, and contaminant transport were constructed and tested against data collected in previous hydrogeological and water-quality studies.
The Delaware Geological Survey (DGS) currently monitors groundwater levels in a network of 68 wells in Delaware. Long time-series of water levels in major aquifers serve as critical baseline data for resource management and analyses of aquifer response to pumping, climatic variability, drought hazards, seawater intrusion, and interaction with streams and their ecosystems.