April 7, 2011
It’s a question that many homeowners have to grapple each season — is my home in danger of being flooded?
With floodplain maps based on old data and changes to community compositions and just where people are living and building today, a definitive answer can be hard to come by. Researchers in Temple University’s Center for Sustainable Communities (CSC) are endeavoring to eliminate any confusion in the 64-square-mile Wissahickon Creek Watershed.
The Center has undertaken a $1.2 million, 30-month study to assess, model, and map flooding problems in the Wissahickon Creek Watershed in Montgomery and Philadelphia counties. The study will include the creation of a Digital Elevation Model for the watershed; an evaluation and field verification of flood elevations and stream obstructions; hydrologic/hydraulic modeling; the preparation of new 100- and 500-year floodplain maps and floodways; and the development of an enhanced stormwater management plan for the watershed.
“Our goal is to prepare new and accurate flood hazard maps to meet and exceed FEMA (Federal Emergency Management Agency) specifications,” said Dr. Jeffrey Featherstone, Director of the Center for Sustainable Communities and a professor in Temple’s Community and Regional Planning program. “The Wissahickon is a critical watershed for the region, particularly in its impact to drinking water for the City of Philadelphia. Since the watershed directly enters the Schuylkill River, it is essential to put the proper stormwater management controls in place.”
The Wissahickon Creek Watershed encompasses including 15 municipalities in Montgomery County and the City of Philadelphia. Municipalities include: Abington Township, Ambler Borough, Cheltenham Township, Horsham Township, Lansdale Borough, Lower Gwynedd Township, Montgomery Township, North Wales Borough, Springfield Township, Upper Dublin Township, Upper Gwynedd Township, Upper Moreland Township, Whitemarsh Township, Whitpain Township, Worcester Township, and the City of Philadelphia.
While the watershed includes extensive park and recreational areas, Dr. Featherstone said, it is heavily urbanized, particularly in its headwaters’ areas. The major tributary to the Wissahickon Creek is the Sandy Run, which drains an area of 12.6 square miles. That subwatershed was extensively studied by the CSC as part of the Fort Washington Flooding and Transportation Improvement Study, which was completed in 2008.
“We’ll continue to build on the work that was completed during the Fort Washington study and the expertise that we’ve been able to build on since we conducted a similar study of the Pennypack Creek Watershed. These types of comprehensive studies are what we know and what we do best,” said Dr. Featherstone. “Since we are able to predict the depths of storms and which roads and bridges will be most affected, PennDOT and local public safety agencies, for example, are interested in the study outcomes for developing emergency management and transportation options during and after storms.”
Dr. Featherstone said as part of the comprehensive study, researchers will create new flood hazard maps, computer simulations depicting water flow and flooding in different flood events, and identify specific stormwater improvements — running models that examine the potential reduction of flooding and pollution and the potential costs.
“A key aspect of this study will be to provide a knowledge base and information for municipalities to prepare stormwater ordinances and stormwater controls required by the Environmental Protection Agency and the Department of Environmental Protection under the Federal Clean Water Act,” he said. “We will have researchers and students on the ground looking at sites throughout the watershed to determine their suitability for stormwater improvements. We’ll be able to give municipal officials detailed information on the nature of a problem and what it might cost to alleviate it — very useful and very practical information.”
Center researchers will prepare an “Act 167” Stormwater Management Plan for the watershed, evaluating the condition and performance of existing stormwater facilities and outlining strategies to improve their performance, including retrofit and alternative stormwater Best Management Practices (BMPs). The CSC already has developed an initial list of stormwater improvements in the watershed and will refine them as part of this study, Dr. Featherstone said.
“This is a study that is literally in our own backyard — the Ambler Campus is in the headwaters of two watershed streams (Tannery Run and Rose Valley Creek) for our study. We’ll look at options to reduce runoff to Tannery Run from the large parking lot on campus,” he said. “We’ll be able to use the campus as a laboratory for our faculty and students to study and implement stormwater management BMPs.”
A working resource for government agencies, community organizations, and developers, the Center for Sustainable Communities provides objective information and services to improve decision-making relative to land use and water resources planning and development. The Center conducts interdisciplinary research and offers educational and community outreach programs.
For more information on the Center for Sustainable Communities, visit www.ambler.temple.edu/csc.