Now in its second full spring season, the stormwater ponds at the Wissahickon Environmental Center (Tree House) are teeming with life! Since the project’s completion in June 2018, the theory “build it and they will come” has been proven true.
Before this Green Stormwater Infrastructure (GIS) project ever came to fruition, the landscape around the Tree House was very different. Surrounded by many invasive shrubs, trees, and herbaceous plants, compacted soil, and a water runoff pattern that eroded the trails and driveway, the area around the Tree House was quickly declining. With the goal of slowing and redirecting the stormwater, and funding from the Pennsylvania Department of Environmental Protection, former FOW Director of Land Management, Peg Shaw, coordinated and oversaw the design (A. D. Marble) and construction (Flyway Excavating) of a series of swales, rock cascades, detention pond, and rain garden complete with new, native, water loving plants.
During the construction period, the sight of open land, removed trees, and heavy equipment was difficult to take in. This mid spring construction was also during a poignant time in the migration and mating season of amphibians, reptiles, insects, and birds, as well as a disruption in the land and food sources for all wildlife. It was difficult at the time to see the beneficial design laid out on paper, or how nature will return, but hopes were high and lessons planned with the anticipation of additional pond habitat and all that it will provide.
No sooner did the construction end and the dirt settle did a storm come through. The ponds filled, the swales flowed into each other, the ground moistened, and life began to return. All in time for summer camp.
As the summer season progressed, staff and campers kept a close eye on the ponds and swales. Everyone noticed the ponds, although meant to recede after the rain, were holding more water longer. This allowed for pond dependant wildlife such the American toad, green frog, and dragonflies to mate and lay eggs that would hatch. Birds bathed in the ponds, and tracks in the mud indicated that raccoons and deer were also using the ponds. So much life in one season ignited excitement for the seasons, and years to come.
The year after its completion was the first full year that wildlife would use the pond, allowing for some interesting life cycles to be completed. And by the second full year, the biodiversity multiplied exponentially.
The Green Frog’s life cycle, for example, has a two-year period between egg and adult, so tadpoles hatched in the summer, will need to survive the winter in the cold mud and muck at the bottom of the ponds. So in the second year, for the first time ever, we discovered numerous pollywogs (or tadpoles with legs and arms) that were well on their way to becoming adult frogs.
Bats were another surprising discovery. Although bats were always seen flying high over the original detention pond area, this past summer more bats were noticed swooping closer to the pond. Wissahickon bats are insectivores, and many insects, like the mosquito and dragonfly, need to lay eggs in the water. So whether they were snacking on incoming or outgoing insects, or both, because the pond was holding water longer, there were more insects for bat snacking.
Additional visitors to the pond included mallards in the deeper water and butterflies on the new native plantings.
Although the positives were many, we did experience a few challenges. The most notable being, what is referred to at the Tree House, as “Toad Rescue”. This done when there are toad and frog tadpoles in the ponds, but because it has not rained, the pond water is nearing drying up. There are two phases to a Toad Rescue: 1. Verland adds water to the pond 55 gallons at a time, until there is enough for the tadpoles to survive until the next rainfall. 2. Trish and Christina collect as many tadpoles from the driest areas as possible, and move them to the small, lined pond by the Tree House bird feeders. This increases survival odds, but there is no doubt that nature also has a solution for these drier times, as we have found tadpoles under the mud, seemingly waiting out the dry period.
Currently, life is in its late winter stages under the mud and ice, visiting at nightfall, or on their way back from far off places. Anticipating a spring with many wildlife and plant observations to see at the ponds, our former annual Sunset Toad Walk, is now a Twilight Pond Walk and will coincide with the City Nature Challenge. The City Nature Challenge is a completion between cities around the world to record through the iNaturalist app the most nature observations, different species, by the most people.
The Twilight Pond Walk (City Nature Challenge) is usually the last Friday in April at the Tree House. Follow us on Social Media for the most up-to-date information about joining the City Nature Challenge, and helping to record the diverse species that that have found their way to the ponds. Life cycles will be in full swing and it’s possible that seeds sprouting, grasses growing, insects buzzing, amphibians singing, and more, will also be found, as the daytime blends with the night.
Photos of the GIS project and ponds.
