Water Quality/Flow

For nearly two centuries, the Wissahickon Creek has occupied a special place in the hearts of Philadelphians who have understood that the waterway is a scenic, recreational and water supply resource that enhances the quality of life in the City. The thousands of people using Forbidden Drive each month know that the quality of the water in Wissahickon Creek is an important aspect of their enjoyment of the Park. 

What far fewer people think about is that the water quality of the Wissahickon is affected by what people do in the entire Wissahickon watershed — the 64-square mile area that drains to the Wissahickon. Roughly three-quarters of the watershed’s area — and 15 miles of the Wissahickon’s 22-mile length — lie outside Philadelphia. So, whether falling rain is washing across the streets of Roxborough or suburban lawns in Upper Gwynedd, the stormwater running downhill to the Creek reflects the lifestyles of the people who live, work and recreate in the watershed. In addition, water quality of the Wissahickon is affected by the treated effluent sewage treatment plants in Montgomery County discharge into the Creek. 

Sewage Treatment Plant Discharge

During dry weather — especially in summer when creek flow is diminished — the five Montgomery County municipal sewage treatment plants that discharge to the Wissahickon dominate the quality of water in the stream. On those hot, sultry days in July, the water flowing in the Creek may well be 90 per cent treated effluent from these plants. All of the Wissahickon’s treatment plants generally are well run and meet their state-mandated treatment standards. Nevertheless, even this treated discharge has elements that are problems for the Wissahickon. Phosphorus and nitrogen — both components of human waste — are not completely removed. Both elements are also key ingredients in fertilizers, so they are often referred to as nutrients. Reference to the Wissahickon’s nutrient problem is a reference to phosphorus and nitrogen. Excessive levels of these two chemicals cause aquatic plants to grow rapidly — a condition that, in time, will diminish levels of dissolved oxygen in the Creek, thereby adversely affecting a wide variety of aquatic organisms living in the stream.

Decades of development and human occupation of the Wissahickon watershed have taken an ecological toll on Wissahickon Creek. Two conditions are necessary to solve the creek’s problems. First, we need a cooperative effort among federal and state agencies and the 12 municipal governments located in the watershed. Second, as citizens of the watershed, we must look at ourselves — how the lives we lead affect the creek — and how we can work together to restore the Wissahickon to the pristine stream we all want it to be.

Water Flow

Click here for information on the flow of Wissahickon Creek at its mouth.