The Dauphin County Conservation District, as the county agency designated to coordinate Act 167 planning in Dauphin County, has been active in such planning since 1990. During the 1990s, several Act 167 plans were developed. During this time frame, “release rates” were the sole stormwater management standard generated by plans, and planning was done on a watershed by watershed basis. Release rates were developed using computer modeling to simulate watershed runoff in response to various size rainfall events. Release rates entail a modification of a planned retention basin to adjust the maximum rate at which stored runoff is released. Based on the timing of streamflows in a watershed, release rates were set typically between 50 and 100 percent for smaller subwatersheds within the modeled watershed. Several plans were developed under this approach, including the Paxton Creek plan, Spring Creek (West) plan and the Multi-Creek plan which covered Beaver, Manada and Bow Creeks and Kellock Run.
The first plan in Dauphin County to go beyond simple release rates was the Mid-Dauphin plan, originally approved in 2003. This plan incorporated additional management standards as Act 167 evolved to keep pace with our improved understanding of stormwater management. In addition to release rates, infiltration, water quality and channel protection standards were developed. These new standards reflected a better understanding of the effects of stormwater runoff not just from a volume perspective but from the perspective of the overall watershed hydrology, including loss of groundwater recharge and effects on water quality, stream morphology and aquatic habitat. Over the next several years, the Wiconisco Creek plan and updates to the Paxton, Spring and Multi-Creek plans incorporated the new approach. All of these plans were still being done on a watershed basis.
The Conservation District is currently coordinating a final plan for Dauphin County. The intent is to provide planning for all remaining unplanned areas and to incorporate existing plans into an overall county wide plan. As Act 167 plans have now shifted from watershed by watershed planning to county-wide planning, this final plan will have the advantage of all watersheds being on the same five year update schedule. It will also incorporate stormwater management standards developed in the Pennsylvania Stormwater Best Management Practices Manual and bring all of Dauphin County into conformity with statewide regulation for post-construction stormwater management planning. The focus of new Act 167 plans, and this final plan for Dauphin County, continues to be addressing stormwater runoff from a holistic water resource perspective.
Act 167 plans are developed with input from three formed committees:
- A Watershed Plan Advisory Committee (WPAC) comprised of municipal representatives that provides overall input for the plan.
- A Municipal Engineers Committee (MEC) that provides technical input for the plan.
- A Legal Advisory Committee (LAC) that provides input on ordinance requirements for the plan.
Upon completion of the plan and review by the municipalities and committees, the plan is forwarded to DEP for review and approval. Once approved, municipalities must implement the plan standards through ordinances within their jurisdiction. New development must develop and implement stormwater management plans that comply with the municipal stormwater management ordinance.
Click here for the status of Act 167 plans for Dauphin County watersheds.
Click here for a map showing the status of Act 167 in Dauphin County.
