Flood Resiliency at the Four Mills Barn

Jamie Stewarti

On August 4, 2020, Tropical Storm Isaias broke all of the rules when it came to our past experience with flooding - the Barn property began flooding within hours of the storm’s arrival and the property began flooding before the creek breeched its banks (flooding first began from stormwater runoff on Morris Rd).  By 3pm the creek had exceeded its banks and floodwaters came into the barn from the creek side as well, resulting in our highest recorded standing water throughout the first floor – 10 inches. Several of the flood resiliency measures that had been in place since the last flood 9 years ago (furniture on blocks, drywall cut back from the floor) could not withstand the quantity of water that flooded the first floor.  Other past flood resiliency measures proved immensely valuable, including the sealed concrete floors and the outlets installed 3 feet off the floor.


We are thankful to our community for stepping up in our time of need. As we tackled the fallout left by the flooding, our community helped in critical ways. Fans and dehumidifiers were loaned to us, generous offers of help, and  donations came pouring in. Thank you to everyone who joined us in our flood response, recovery, and resilience efforts. With our plans to make the Barn more flood resilient, the next time the Barn floods the costs of recovery should be minimal.


Given that storms like Isaias are going to be more frequent owing to climate change, the most important consideration as we move forward is thoughtfully incorporating further flood resiliency into our recovery plans.  The goal being that when the next big storm comes we will only have to clean, sanitize, and dry the first floor.  In order to achieve this goal, we will need to make some much-needed and significant changes to the Barn’s interior.  This includes:


  • Cutting back the drywall to 3 ft. from the floor and installing water resilient insulation

  • Covering the open walls with a treated wood wainscoting, that can be removed after a flood to dry everything out and then reinstalled

  • Moving all of the staff offices as well as the HVAC up to the second floor


The Four Mills Barn is an historic and iconic building in our region. It is home to our staff and it provides public programming and event space for engaging the community in our mission.  Unfortunately, it is located in the floodplain and it is a stones-throw from the Wissahickon Creek, making it unavoidably vulnerable to flooding. Wissahickon Trails is committed to stewarding this facility for the community and our staff by making the first floor flood resilient and ready for the more frequent and intense storms anticipated in the months and years to come.