DEP Water Quality Protocol Headed for Another Round of Public Comments

The Pennsylvania Department of Environmental Protection (“DEP”) has developed a suite of Assessment Methods that are intended to be used to collect and assess water quality data for use in compiling the biennial Integrated Water Quality Monitoring and Assessment Report. This report is submitted to EPA pursuant to Clean Water Act Sections 303(d) and 305(b), and covers the listing of impaired waters in the Commonwealth. DEP sought public comments on these Assessment Methods in late 2015.

Perhaps the most significant of the new Assessment Methods is the “Nutrient Impact Assessment (“NIA”) Protocol for Wadeable Streams.” The intended use of the NIA Protocol is to determine if nutrients are a cause of impairment after a given stream is determined to be Aquatic Life Use (“ALU”) Impaired, based on benthic macroinvertebrate data. If DEP believes that nutrients are a potential cause of the ALU impairment, the NIA Protocol used to confirm or reject nutrients as a cause of the impairment. As proposed, the NIA Protocol consists of two tiers of data evaluation. Tier 1 evaluates certain screening parameters, including total phosphorus (“TP”) and total nitrogen (“TN”). If one or more of the Tier 1 screening parameter values equals or exceeds a given benchmark value, a Tier 2 data evaluation is undertaken, which involves an evaluation of continuously monitored Dissolved Oxygen (“DO”) data. Under the NIA Protocol, it is the continuously monitored DO data that will be used to determine if nutrients are a cause of the ALU impairment.

A number of comments were submitted to DEP regarding the NIA Protocol, with some questioning the science behind the document. DEP recently issued a letter in which it stated that the purpose of the NIA Protocol is to develop a standardized tool for determining when nutrients are a cause of a previously identified ALU impairment. However, DEP also acknowledged the receipt of a number of comments to the proposed NIA Protocol, noting that these comments are under consideration and will be factored into revisions to the NIA Protocol. Significantly, DEP will afford the public an opportunity to comment on any revision to the NIA Protocol before the document is finalized. Look for additional information on subsequent posts to this Blog.

Steve Hann submitted comments to the NIA Protocol on behalf of the Pennsylvania Municipal Authorities Association.