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Stormwater Runoff

One of Rose Valley’s most cherished features is its location within the Ridley Creek Watershed, right on Ridley Creek and Vernon Run. Rose Valley's waterways have always been an integral part of the community, first as the economic driver of the area powering a number of mills, and then as a point of pride and recreation. At one time, residents boated and swam in the man-made pond just upstream from the Old Mill.  Today, visitors to Saul and Chadwick enjoy the calming effect of water during their walks. Students from the School in Rose Valley use the stream for science projects. Children who visit and live along the creeks do creek walks, hunt for pottery shards on the creek beds, and observe wildlife like fish, frogs, snapping turtles, and birds.


With this enjoyment, however, comes the responsibility to care for and protect our waters.  Sadly, according to the Pennsylvania Department of Environmental Protection (DEP) 94% of Delaware County’s waterways, nearly all of the Ridley Creek Watershed, and 100% of Rose Valley’s waterways are impaired

An impaired waterway is one that cannot fulfil its intended purpose, whether that’s safe recreational use, potable water, or sustainable wildlife habitat, due to pollution and/or siltation.  The reason given by the DEP for the “impaired” designation of our waterways is siltation from stormwater runoff.

What is a watershed?

A watershed is a region in which all water flows to the same waterway. Rose Valley is located in the Ridley Creek and Delaware River Watersheds. 

Click here to learn more about how our actions impact the water beyond our Borough.

What is stormwater runoff?

Rain is an important part of our ecosystem, nourishing Rose Valley’s prized trees, gardens, and preserves and feeding our cherished waterways - Ridley Creek and Vernon Run. 

When rain falls on Rose Valley, some of it forms puddles or small ponds that eventually evaporate. Still more is slowed by our trees, soaked up by the earth (a process called “rainwater infiltration”), and held in place by the roots of native plants. The roots and earth filter out any pollution or particulates and slow the water as it travels to our waterways. 

Any rain or melting snow that doesn’t evaporate or soak into the ground is called stormwater runoff. 

Why do we need to manage our stormwater runoff?

When rain falls on impervious surfaces like our roofs, driveways, and roads, there is nothing to slow it down and clean it. The same is true of lawns, which offer poor rainwater infiltration

This water can flow to our homes and historic structures, threatening them with flooding and water damage. As stormwater runoff travels to our storm grates, it erodes both earth and pavements, damaging our roads and bridges. 


This excess water picks up oil, fertilizers, chemicals, debris, and pet waste, and carries those pollutants to the waterways, making the water unsafe for use by humans, as well as for the birds, animals, and insects that rely on Ridley Creek and Vernon run for food and water. 

When it reaches Vernon Run and Ridley Creek, the increased volume of the water threatens the trees and structures along those waterways with erosion and flooding.  

The dirt and debris the water carries are deposited into the streams, making the water shallower and, therefore, warmer. This change in temperature impacts the aquatic life in the stream, making it difficult for fish and amphibians to survive.

What is Rose Valley Borough doing about Stormwater Runoff?

Recognizing the dangers of unmanaged stormwater runoff, the Pennsylvania legislature enacted the Stormwater Management Act in 1978. Each county in Pennsylvania is required to create a stormwater management plan, known as an Act 167 Stormwater Management Plan.  Any municipality in Pennsylvania that discharges its stormwater runoff into a waterway must obtain a Municipal Separate Stormwater Sewer System (MS4) Permit.  Permittees are required to perform a series of tasks, education, training, and reporting each year in keeping with Act 167 requirements. 

Rose Valley Borough has a MS4 permit and takes its commitment to these requirements seriously. You can find a copy of Rose Valley’s MS4 permit, our Stormwater Runoff Management Plan, our Stormwater Ordinance, and our Pollutant Reduction Plan here. (Link coming soon. Contact the borough office for these documents.)

For more information about the requirements of an MS4 permit, see this training from the PA DEP:


Rose Valley Borough's most important job is supporting resident efforts to manage the stormwater runoff from their own properties.  

What can residents and landowners do to reduce stormwater runoff?

Reducing the amount of runoff, pollutants, and sediment leaving residential property will be a big part of the solution to Pennsylvania’s stormwater runoff problem.  By making a few simple changes around your home and yard, you can easily become part of the solution. 


Watch this quick video on ways you can reduce runoff and water pollution, then visit our resources page Manage Your Stormwater Runoff for a detailed list of ways you can help reduce runoff and pollution in our waterways.

Rose Valley Borough Town Pollution Watch - Reporting Illicit Discharge

Rose Valley Residents can help prevent pollution and damage from runoff by reporting problems they notice in their neighborhoods and local streams. Residents sometimes may be the first to recognize “illicit” discharges being directed into storm sewers or flowing out of storm sewer outfall pipes into streams. “Dry Weather Flows” (flows from outfall pipes after a 72 hour or greater period without rain) should be reported to your municipality for further investigation.

New stormwater regulations from Pennsylvania’s DEP require that your municipality investigate more thoroughly potential illicit discharges (pollutants) into our streams. You can help by promptly reporting the following events to the authorities listed in the hotline boxes below. Here are some of the conditions that you should report and to whom they should be reported:

  • Water Main Breaks (Aqua)

  • Observed pollution event or pollutants in stream (DEP)

  • Clogged or leaking sewer lines (Southwest Delaware County Municipal Authority)

  • Dry weather flows from outfall pipes into streams (Rose Valley Borough)

  • Illegal dumping into water courses or storm sewers (Rose Valley Borough or DEP)

  • Spills, hazardous materials (DEP Spills or PEMA hotlines)

  • Inadequately treated sewer effluent from treatment plant (Southwest Delaware County Municipal Authority, DEP)

  • Fish Kills (Fish Commission, DEP)

  • Sediments leaving a construction site during rain events and other violations (Delaware County Conservation District; send photo if possible) 

  • Water pollution events also can be reported online at the DEP website: Select “Environmental Complaints,” then “Southeast Region”

Rose Valley Citizen Water Quality Hotlines

PA DEP Emergency Phone: 484-250-5900

Rose Valley Borough Phone: 610-566-2040 (9 am to 12 pm)

Emergency Service – 9 1 1

DEP Water Quality Complaint Hotline Daytime: 484-250-5991, Weekdays 8:30 am to 4:30 pm

DEP 24 Hour Water Quality Hotline: 484-250-5900, Anytime, including Evenings & Weekends

Specific Situations:

  • Spills & Other Emergencies Hotlines: PA DEP, 484-250-5990; PA Emergency Management Agency, 1-800-424-7362

  • Offsite discharge of Sediment, erosion & Other improper controls during construction: Delaware County Conservation District, 810-892-9484. Be prepared to send a photo, if possible, along with the Full Address & Directions.

  • Clogged or leaking Sanitary sewer lines or Sewage smell in creek: Southwest Delaware County Municipal Authority, 610-494-1335.  After Hours: Call 911

  • Fish Kills; Illegal Fishing: PA Fish Commission 717-626-0228 or DEP Water Quality 484-250-5900

  • Dry Weather Outfall Flows: Rose Valley Borough, 610-566-2040 (weekdays, 9 am to 12 pm)

  • Broken Water Mains: Aqua PA 610-525-1402 (24 Hrs, 7 days) 

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