Category: Stormwater Projects

Harriton Preserve Restoration

The Conservancy recently received a Growing Greener Plus grant from the Pennsylvania Department of Environmental Protection to expand and restore habitat at the Preserve at Harriton, in partnership with the Friends of Harriton Preserve (FHP) and Lower Merion Township (LMT). The Preserve at Harriton is an 8.9-acre parcel within Harriton Park in Bryn Mawr. The Preserve contains woodlands and two streams, including a section of Mill Creek. The Harriton Association maintains the buildings and upper section of Harriton Park while LMT works with the FHP to maintain the 8.9-acre Preserve. Invasive plants like multiflora rose and Japanese knotweed occupy large, spreading sections of the Preserve. Most local pollinators cannot eat multiflora rose or Japanese knotweed, so the populations of pollinators – and other important organisms – at the Preserve are lower than they could be.

We plan to cut back the patches of multiflora rose and Japanese knotweed regularly for two growing seasons to counter their spread. The cuttings will weaken the plants, creating room to plant new native plants, like the successful efforts at the Cynwyd Heritage Trail. Weakened plants are easier to cut back than established ones, so volunteers can handle more of the maintenance in the future. After two growing seasons of cutting, we will replant the area with a diverse mix of native plants to restore the woodlands and expand the riparian buffer. 

The plantings will create ecological benefits at the Preserve and serve as an example for other streamside properties. We are excited to get started and will share updates as the plans develop.

Cynwyd Heritage Trail Wildlife Habitat Expansion

In 2020, the Conservancy received a grant from the National Fish and Wildlife Foundation to improve stormwater management, restore wildlife habitat, and improve recreational access on the Cynwyd Heritage Trail and along sections of Vine Creek. During heavy rain storms, water rips down sections of the Cynwyd Heritage Trail, forcing gravel, sediment and other pollutants to wash over the trail before flowing into the adjacent Vine Creek and the Schuylkill River. The rain water pouring onto the trail and into the creek comes from storm sewer pipes, which take on uphill impervious surfaces, including streets, roofs, driveways, parking lots, and shallow-rooted turf grass. Runoff along the Cynwyd Heritage Trail increases water velocity, exacerbates flooding and worsens erosion, sending more sediment downstream. Excess sediment cuts off light to important aquatic plants and smothers aquatic animals. Even small rain storms have an impact. 

There are ways to mitigate stormwater runoff that do not involve underground piping, walls, holding tanks or culverts that dump unfiltered water into our streams. These green strategies naturally capture and filter stormwater, and if done correctly, are sustainable and greatly beneficial to the health of wildlife and people. Strategies include: planting trees to form deep root systems that absorb water, stabilize soil and shade streams; replacing mowed lawns with native meadows; diverting stormwater from its impervious source towards planted spaces; and increasing the width of riparian areas to slow and dissipate water during high stream flows.

Implementing these green strategies at a scale that can make an impact, restore and create vast areas of wildlife habitat, and produce measurable improvements in stormwater capture can be challenging. The Conservancy recently contracted with Gray Landscape Design, LLC to design and help implement a plan for achieving the goals of the grant. In consultation with Gray Design, the Friends of the Cynwyd Heritage Trail and Lower Merion Township, planting plans were developed for a portion of the trail. Duranti’s Landscaping implemented the plans in fall 2022. Swing by the Trail to see the plants!

Delmont Avenue Green Street

The Conservancy is working with the residents of Delmont Avenue in Ardmore to plant native plants, de-pave, establish rain gardens, redirect piped downspouts, and install flow through planters, all to slow down stormwater.

The efforts on Delmont Ave. are an expansion of the Stream Smart program. After the initial success of Stream Smart, the Stream Smart partners joined with other Delaware River Watershed Initiative organizations to create a more hands-on expansion of the program. The new proposal to install green stormwater projects on a residential scale was deemed worthy of a National Fish and Wildlife Foundation Cornerstone Grant. 

Properties have varying amounts of impervious coverage, gutter downspout orientations, available space for new plantings, and utility locations, so each project has been unique. The overarching goal – to slow down and clean as much stormwater as possible – remains the same.

Delmont Avenue was selected as the pilot block because of enthusiasm for the project on the street. The knowledge, energy, and passion of the neighbors has made the efforts more cohesive and, ultimately, more impactful. The Conservancy hopes that the Delmont Avenue Green Street can serve as a model for other streets in the future. See some of the completed work below. If nothing appears, view the Story Map here.