Pennsylvania Stormwater Best Management Practices Manual
Brownfield sites have a wide range of complexity, primarily dependent on previous, existing and
proposed land use. Land development at brownfield sites normally occurs in two stages: (1) site
remediation and (2) redevelopment. Planning, design and construction work associated with
these two stages typically involve separate consultants and/or contractors. There are very few
practitioners who perform both stages of work. This bifurcation of responsibility can potentially
lead to miscommunication, mistakes and problems. It is critical that both parties coordinate and
are mutually agreeable to the proposed activities at the site.
When applying for permits for a brownfield site (for either stage), it is imperative that the applicant
provide full disclosure, including but not limited to the following information:
1. Existing and previous land uses
2. Potential pollutants, along with a summary of sampling data.
3. Source and location of the potential pollutant(s) on the Erosion and Sediment Control
(E&S) Plan drawings,
4. A description of what measures are proposed to manage and control discharges of these
pollutants to eliminate the potential for pollution to surface waters of the Commonwealth.
7.2.1 Site Remediation (i.e. Cleanup)
The site remediation stage does not typically generate new impervious surfaces. In fact,
remediation may reduce impervious area through the demolition of buildings and other
impermeable surfaces. These areas, along with other earthmoving related to the cleanup, are
usually temporarily stabilized until the site is redeveloped. As a result, this stage of land recycling
does not typically require structural infiltration stormwater BMPs. The focus of site remediation
routinely involves earthmoving to address soil and groundwater contamination. The stormwater
management portion of this work is normally limited to non-structural BMPs, consisting of detailed
construction sequencing or other measures to prevent the transport of contaminated runoff from
How stormwater is managed on brownfield sites depends largely on how the site was remediated.
Contaminated soil can be completely removed from the site, contaminated soil can be isolated
and capped, or contaminated soil can be blended with clean soil so that it meets state standards
for public health and safety. For more information on site remediation, go to:
7.2.2 Site Redevelopment
Most of the site improvements occur in the redevelopment stage. It is imperative that this stage
of the project does not disturb any completed work from the site remediation stage (e.g. a cap or
other cleanup remedy). Conflicts most frequently arise during the foundation work or utility work
phases of a project. Utility lines, in particular, are often overlooked and can have a major impact
by opening new preferential pathways for contaminants to migrate. Each stage should be
considered independently; ideally, the remediation work should be completed prior to
commencing redevelopment work.
The redevelopment stage is where any net increase of impervious area would be expected to
occur; thereby leading to increases in the rate and volume of stormwater runoff. Even where
there is no net increase in impervious area, the existing site is usually devoid of any notable
stormwater management BMPs. This is the stage where post-construction stormwater
management must be addressed.
363-0300-002 / December 30,
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