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Stormwater Management Plans

A Stormwater Management Plan provides a mechanism for municipalities within the watershed to plan for and manage increased runoff associated with future development and land use changes.

The purpose of a watershed plan is to provide a watershed-wide (as opposed to municipal or site) approach to stormwater management since runoff does not recognize municipal boundaries. By treating the watershed as a single unit, we can achieve a coordinated approach to stormwater management that enables us to not only maintain runoff peaks, but allows for timing relationships of runoff.

This type of plan will provide local ordinances that incorporate standards and criteria to manage and maintain peak runoff flows throughout the combined watersheds as development occurs. Also, it is not the intent of this plan to solve existing flooding or runoff problems, but to identify them for future correction and assure that problems do not get worse. More specifically, this plan does not require the municipalities to correct existing drainage problems.

There are presently two Act 167 stormwater management plans that have been adopted in Clinton County: Chatham Run and Fishing Creek. In Clinton County, the Conservation District has been the lead agency responsible for preparing the two stormwater management plans now in effect for our county; while other county government offices are participating organizations. Specific government offices from each county participating in the planning process are listed under the WPAC example section below for Fishing Creek's stormwater management plan.

A stormwater management plan is generated within a watershed in order to comply with the Stormwater Management Act of 1978 (Act 167), which requires each county in Pennsylvania to prepare and adopt a stormwater management plan for each designated watershed in the county.


Requirements and Planning Process of Act 167

The following summary includes the basic elements of Act 167 in terms of specific responsibilities assigned to various units of state and local government:

1.  Each county shall develop regional stormwater management plans for each watershed within its boundaries, recognizing that most watersheds will cross county boundaries, and will require collaboration with neighboring counties.

2.  Each municipality will adopt local ordinances and engineering design criteria which conform to the provisions of their respective stormwater management plans.

3.  Developers must implement stormwater management techniques that meet the standards and criteria set forth in the appropriate municipal ordinances, as supported by the watershed stormwater management plan. In general, these stormwater management techniques will ensure that post-development runoff rates throughout the watershed do not exceed pre-development levels.

PA Department of Environmental Protection will serve as the review agency for each watershed storm water management plan submitted by the counties.


The Act 167 planning process involves three essential steps:

1.  Documentation of existing watershed characteristics, including land use, soils, runoff conditions, peak flows, sub-area timing relationships, existing storm drainage problems, and flow obstructions. The existing conditions in the watershed represent the base line for evaluating the effects of future runoff caused by land development.

2.  Preparation of a watershed stormwater management plan to manage stormwater based on possible future development and land use change within the watershed. The plan includes criteria and performance standards for managing urban runoff, and a listing of alternative stormwater management techniques.