Environmental

Neville Township is a five-mile long 1,200-acre island in the middle of the Ohio River downstream of Pittsburgh, Pennsylvania. The eastern end of the island has heavy industry including coke and steel, cement, oil terminals, and chemical manufacturing.  The western end of the island has a large Superfund site.  The residential central section of the island is bisected by an Interstate exchange.  The 1999 Comprehensive Plan identified Areas of Opportunity for future development.  The 2001 Environmental Strategic Plan (ESP), also prepared by Chester Engineers, represented the environmental foundation for implementing the Comprehensive Plan.  The objective was to evaluate how environmental conditions might impact planning and to provide background information in support of a USEPA Brownfield Assessment Grant.  Project activities included site history, parcel evaluation, prioritization for further consideration, and public participation.

The municipality and several golf courses within its boundary depend on groundwater pumped from a regional aquifer.  The municipality also operates a waste water treatment plant that was thought to be a source of a regulated contaminant, nitrate, which had been found in wells.  A portion of the treated waste water was recycled to irrigate publicly-owned golf courses.  However, the majority infiltrated the ground beneath storage lagoons.  The objectives were to characterize the extent and degree of groundwater contamination, to identify sources, to quantify contributions from the public waste water treatment plant, and to evaluate by computer modeling the potential benefits of alternative mitigation efforts.  The groundwater flow and transport model developed for the project is regional in scope, extending across the breadth of the regional aquifer and incorporating two regional aquifer layers, each of 500 feet thickness.

Indianapolis Water Company (IWC) needed hydrogeologic expertise to guide the construction, testing, and permitting of their White River North Well Field at a location selected by IWC.   IWC considered the addition of this well field crucial for meeting projected water demands.  The property available for well construction surrounded a water-filled former gravel pit, which created a concern of potential surface water influence.  If present, surface water influence would significantly increase raw water transmission and treatment costs.  Analysis of the subsurface geology revealed that the aquifer beneath the property was a buried valley that had once been a tributary to the White River.  The walls of the buried valley sharply limited the extent of the aquifer supplying groundwater to the wells.  Furthermore, the buried valley was also determined to be a source to another well field operated by a different water company.  Each of these factors was recognized as likely limits to the long-term sustainable yield of the well field.  Another challenge arose from the fact that the durations and rates of pumping anticipated to occur in actual operation significantly exceeded the limits of temporary pumps and water handling capacities available for performance testing.

This site is regulated under the federal Resource Conservation and Recovery Act (RCRA), with oversight delegated to ADEM. The site has contaminated groundwater in both the overburden and the bedrock, and local occurrences of non-aqueous phase liquids. The bedrock is predominantly dolomite, having sparsely distributed solution conduits characteristic of geomorphically immature karst. The solution conduits locally accelerate groundwater flow velocities. The groundwater quality assessment focused on organic compounds, metals, ammonia, and sulfate. Installation of offsite perimeter wells involved extensive negotiations with property owners, including mining companies, metal tube manufacturers, and railroad companies. Loose overburden conditions made the drilling difficult. ADEM required comparison of the groundwater quality results with five sets of screening criteria: (1) concentration limits specified in the site RCRA permit; (2) federal Maximum Contaminant Levels; (3) federal Secondary Maximum Contaminant Levels; (4) EPA Region IX Preliminary Remediation Goals; and (5) background concentration data from the earlier Phase I and II RCRA Facility Investigations (RFIs).