St Mary's Villa Project: What Upper Dublin and the Developers Need to Know

A comprehensive and safe solution to the stormwater runoff and general rain from the rooftops and macadam parking lots of the proposed development must be created and implemented. The man-made “stream bed” which runs down towards Farm Lane and through the culvert is currently taking on much more runoff from the Loch Alsh dam than it was ever designed to handle. This water, which can rush as voluminous rapids through the Farm Lane and Highland Avenue culverts whenever the Loch Alsh dam overtops, is the very reason so many homes were damaged in downtown Ambler during the tropical storm in 2012.

If you don’t believe me, follow this “stream bed,” which runs under Highland, back through Inverness and the downhill neighborhood, crosses under Bethlehem Pike and runs straight towards Ambler and the Wissahickon. The houses on Highland Avenue have been flooded by Loch Alsh overtopping for many years, permanently damaging these homes. Loch Alsh was designed by Mattison and now takes on the watershed above it. A couple of years ago, Upper Dublin allowed the Loch Alsh reservoir to take on stormwater from 309 and the new high school. Take a walk up to the east side of 309 on the high school sports fields side and see for yourself the many  culverts built under 309 to drain all of the parking lots and sports fields stormwater straight into Loch Alsh reservoir. The reservoir was not designed to take on this water.

When Loch Alsh overtops (floods), it causes extensive damage to homes “downstream” and even threatens lives. This development cannot dump one more drop of runoff into this “stream bed.” Loch Alsh, the spillover and the “stream bed” are overwhelmed during rain storms. Per Ambler Borough engineer, one inch of rainwater causes the Loch Alsh dam to rise one foot. Ambler Borough tries to keep the levels minus 4 feet below the lip.

In these past few years, we have had rain comparable to 100-, even 1,000-year storms. In 2009, we received 6 inches-plus rain within an hour! Overtopping at Loch Alsh reservoir is already assured during heavy storms and rainfall. Upper Dublin has spent your taxpayer money to build culverts and systems to install stormwater solutions. The developers will have to put a lot of planning and expense into creating a place to send the property’s stormwater runoff — because they cannot send it down this route.

I have studied this issue extensively; I have worked with Kurt Kreider of the DEP and wetlands and engineering experts in finding resolutions. I am very concerned for the safety and impact this development will have on many neighborhoods in Ambler including our immediate neighbors of Lake and Villa drives and Farm Lane. I am anxious to hear their plan.

No doubt, with the new traffic light installation proposed on Bethlehem Pike, Farm Lane, Villa Drive and Van Sant will become shortcuts for many commuters driving north on Bethlehem Pike. Sadly, our quiet streets and safe hamlet will be dramatically changed.