Lower Merion Township included Shortridge Phase 3 in their 2018 MS4 permit, ensuring that the project would move forward. Under the guidance of Lower Merion Township Parks and Recreation Director Donna Heller, the project was designed to re-connect the stream to its floodplain. The project utilized large rocks only in areas where mature trees were established too close to the bank for re-grading. In most areas, the banks were re-graded, coir logs were placed for stabilization, and many new perennials and shrubs were added. The design allows water to spill onto the banks during storms as it would under natural conditions. When streams can spill onto their banks, their overall flow slows down. Some of the water is absorbed and cleaned by nearby plants and erosion rates are reduced. As the new plants establish, the coir logs will break down. In a few years, the plants will stabilize the banks on their own.

Over time, most stream related projects in our area have involved channelizing stream banks in an attempt to control streams. Anywhere there are concrete or stone walls along streams, someone attempted to control stream flow. Not only does this channelization process disrupt streamside habitat, it also speeds up streams during storms, leading to more erosion and flooding downstream. 

As long as stormwater runoff remains a problem, erosion and flooding will continue to be an issue. Re-grading and planting stream banks will not heal our streams but are important steps. During Lower Merion Township’s 2018-2023 MS4 permit, most restoration projects will directly work on streams. This does not get at the heart of the issue, stormwater runoff, but these areas are accessible and the work required is more affordable. Altering roads or sidewalks enough to capture meaningful amounts of stormwater is very expensive. That work will be necessary down the line but any efforts to slow the flow of streams during storms and filter out pollutants can be valuable. Another large portion of the stormwater runoff equation is hard surfaces on private properties. To learn how you can mitigate your stormwater impact and help heal our streams, email Tom@lmconservancy.