Centralized impoundments are wastewater-holding facilities that are:

• A natural topographic depression, manmade excavation or diked area formed primarily of earthen materials.

• Designed to hold fluids or semifluids associated with oil and gas activities, including wastewater, flowback and mine influenced water, the escape of which may result in air, water or land pollution or endanger persons or property.

• Constructed solely for the purpose of servicing multiple well sites.

Centralized impoundments are frequently used by drilling operators to hold vast quantities of hazardous fracking flowback and produced water generated by unconventional shale wells. Centralized impoundments differ from other types of impoundments by being associated solely with hazardous waste, as compared to freshwater dams, and by serving to hold waste from multiple wells and/or well pads in the area surrounding them.

Centralized Impoundment Permits

In order for an operator to build a centralized impoundment (CI) in Pennsylvania, they must apply for a Centralized Impoundment Permit.

Parts of the permit application beyond basic operator, certification, and engineering information for the process include:

• Permit application fee: An application fee which is determined by how high the proposed dam embankment will be.
• Act 14 Notification: Essentially, this requires operators to inform the local and county governments that they want to build a CI at least 30 days before permits are issued and construction begins.
• Cultural Resource Notice: Requires operators to inform the Natural Heritage Program of their intentions, in the case where the impoundment may be near historic and/or archaeological sites.
• PNDI Search Receipt: This checks that operators complete a Pennsylvania Natural Diversity Inventory (PNDI) before construction. This is of particular importance if the proposed site is in a state or national natural area.
• Color Photographs: Photos which clearly illustrate the area watercourses, wetlands, and current water conditions.
• ESCGP-2: Another type of permit, this stands for Erosion and Sedimentation Control Plan.
• Maps, Plans, Profiles, and Cross-Sections
• Impacts from Dam Failure: This is an estimate of what the impacts and damages could be if the well were to break, with attention to houses, roads, serious property damage, and other human structures.
• Groundwater Protection Requirements: Verifies operators know the impoundments must be lined with impermeable membranes (at least 40 mils thick), and requires a working leakage detection system and working groundwater monitoring system be installed.