4. Sacony Creek - Act 167 Plan Update, adopted 2007
5. Manatawny Creek - In Phase I stage
6. Little Lehigh Creek - adopted Act 167 Plan, 5-year update complete
7. Perkiomen Creek - In Phase I stage
8. Swamp Creek - Act 167 Plan, adopted
9. Conestoga River - Act 167 Plan adopted 2005
10. Swatara Creek - In Phase I stage
11. French Creek - In Phase I stage
12. L. Schuylkill River - In Phase I stage
13. Cocalico Creek - Act 167 Plan adopted 2001
Stormwater Runoff - Its Problems and Its Solutions
The water that runs off the land into surface waters during and immediately following a rainfall event is referred to as stormwater. In a watershed undergoing urban expansion, the volume of stormwater resulting from a particular rainfall event increases because of the reduction in pervious land area (i.e., natural land being covered by pavement, concrete, or buildings). That is, the alteration of natural land cover and land contours to residential, commercial, industrial and even crop land uses results in decreased infiltration of rainfall and an increased rate, volume of runoff and pollution.
As development has increased, so has the problem of dealing with the increased quantity of stormwater runoff. Failure to properly manage this runoff has resulted in greater flooding, stream channel erosion and siltation, as well as reduced groundwater recharge. This process occurs every time the land development process causes changes in land surface conditions.
History has shown that individual land development projects are often viewed as separate incidents, and not necessarily a part of a "a bigger picture". This has also been the case when the individual land development projects are scattered throughout a watershed (and in many different municipalities). However, it is now being observed and verified that this cumulative nature of individual land surface changes dramatically affects flooding conditions. This cumulative effect of development in some areas has resulted in flooding of both small and large streams with property damages running into the millions of dollars and even causing loss of life. Therefore, given the distributed and cumulative nature of the land alteration process, a comprehensive (i.e., watershed-level) approach must be taken if a reasonable and practical management and implementation approach and/or strategy is to be successful.
Pennsylvania Storm Water Management Act (Act 167)
Recognizing the need to deal with this serious and growing problem, the Pennsylvania General Assembly enacted Act 167. The statement of legislative findings at the beginning of the Pennsylvania Storm Water Management Act (Act 167) sums up the critical interrelationship between land development, accelerated runoff, and floodplain management. Specifically, this statement of legislative findings points out that:
1. Inadequate management of accelerated runoff of stormwater resulting from development throughout a watershed increases flood flows and velocity, contributes to erosion and sedimentation, overtaxes the carrying capacity of streams and storm sewers, greatly increases the cost of public facilities to carry and control stormwater, undermines floodplain management and floodplain control efforts in downstream communities, reduces groundwater recharge, and threatens public health and safety.
2. A comprehensive program of stormwater management, including reasonable regulation of development and activities causing accelerated runoff, is fundamental to the public health, safety and welfare and the protection of the people of the Commonwealth, their resources and their environment.
Up to the enactment of Act 167, stormwater management had been oriented primarily towards addressing the increase in peak runoff rates discharging from individual land development sites to protect property immediately downstream. Minimal attention was given to the effects on locations further downstream (frequently because they were located in another municipality), or to designing stormwater controls within the context of the entire watershed. Management of stormwater also was typically regulated on a municipal level with little or no designed consistency between adjoining municipalities in the same watershed concerning the types, or degree, of storm runoff control to be practiced.
Act 167 changed this approach by instituting a comprehensive program of stormwater planning and management -- on a watershed level. The Act requires Pennsylvania counties to prepare and adopt stormwater management plans for each watershed located in the county, as designated by the Pennsylvania Department of Environmental Protection (Department). Most importantly, these plans are to be prepared in consultation with municipalities located in the watershed, working through a Watershed Plan Advisory Committee (WPAC). The plans are to provide for uniform technical standards and criteria throughout a watershed for the management of stormwater runoff from new land developing sites.
The types and degree of controls that are prescribed in the watershed plan need to be based on the expected development pattern and hydrologic characteristics of each individual watershed. The management plan, specifically the standards and criteria, are to be developed from the technical evaluations performed in the planning process, in order to respond to the "cause and effect" nature of existing and potential storm runoff impacts in the watershed. The final product of the Act 167 watershed planning process is to be a comprehensive and practical implementation plan, developed with a firm sensitivity to the overall needs (e.g., financial, legal, political, technical, environmental, etc.) of the municipalities in the watershed.
