Stormwater runoff pollution is one of the greatest threats to our region’s waterways. In addition to flood mitigation, an improvement to the dam or immediate tributary area could also assist Lower Gwynedd Township’s goals as part of the Municipal Separate Storm Sewer System (MS4) program.

Should a practical and economically feasible improvement be identified, a plan would be submitted to DEP/FEMA along with a Letter of Map Amendment (LOMA) with a goal of amending the FEMA maps and ultimately reducing the flooding issues in the area. Once the study is finalized, the Township will evaluate all options and determine how best to proceed. The goal of this study is to evaluate possible modifications to the dam or grading improvements that could be made to effectively reduce the rate and volume of water reaching the neighborhood to the south of Knight Road and the Ambler Yards Business Campus. The Ambler Yards Campus holds approximately 28 business that are affected in extreme rain events.

The creek then flows into a culvert under Spring Garden Street and through existing pipes under the Ambler Yards Business Campus until it reaches the culvert at the railroad tracks, and ultimately discharges into the Wissahickon Creek. Once the flow continues past the dam, it crosses under Knight Road and flows along the front and rear yards of approximately 25 homes on Brookside and Marion Avenue. The drainage area to the dam is approximately 123 acres and extends to Mount Pleasant Avenue (east), Houston Road (west), and across Bethlehem Pike (north) on either side of Alene Road, just north of Hamilton Road. Houston Creek runs northeast to southwest and flows through the School District property to an existing dam. The primary locations to be analyzed are the existing stone/concrete dam and a portion of the creek between Brookside & Marion Avenue from Knight Road to N. The project area is located on the border of Lower Gwynedd Township, Ambler Borough and Whitpain Township between the Wissahickon School District property and the Ambler Yards Business Campus. The study is to determine the baseline flooding conditions of the neighborhood adjacent to the Wissahickon School District property and the drainage area of the existing dam. Over the past two years, the Township's Engineer has been gathering information and performing analysis. Lower Gwynedd Township received grant funding to conduct a flood study in 2021 through the Department of Community and Economic Development's Flood Mitigation Program.

Lower gwynedd township