by David Murphy
Flood prevention is a hot topic among regional planners everywhere. It's no secret that urban regions like the Delaware Valley have seen an increase in the number of areas that flood over the past several decades. The reason is urban spawl. New development often leads to flooding downstream because roads and buildings don't absorb water as earth does. Every new shopping center, housing development and highway further limits the amount of available ground that can ingest snow melt and rain water.
Efforts to curb the flow of water also have negative effects. Every time someone upstream builds a culvert or retaining wall to limit the spread of a creek or stream, additional water is forced downstream, making the problem even worse there. This explains why, for example, the borough of Darby along the Darby Creek began seeing flooding during the 90s far worse that what anyone had seen before. In fact, it got so bad that government entities eventually wound up purchasing and demolishing several homes that had become part of a new flood plain. The families were relocated; an expensive and difficult undertaking.
Nowadays, there are strict controls on new construction in an effort to keep things from getting worse. In newer developments, you may notice large, fenced-in depressions near recently constructed homes and businesses. These are drainage basins, now required by ordinance and designed to take in excess rainwater. New paving materials are also being used that allow some rain water run-off to penetrate the road surface, instead of running into storm drains and subsequently, into streams and creeks.
A bigger problem exists in the Midwest along large rivers like the Mississippi. Not only are heavy rains and snow common in this region, the rivers have been dammed and levied heavily, as agricultural interests try to claim as much fertile farmland as possible. But invariably, these levees can not consistently hold back the great volume of water that accumulates during a large storm. Breaks are common and, in fact, have been responsible for some of the area's worst flooding events. It's not only a deadly problem but an expensive one, as we all pay the billions in costs through higher food prices and insurance rates. Solutions aren't easy to come by, as the desire to lessen the threat posed by extensive damming of rivers is often at odds with the need to maximize profits and make use of the fertile land.
But the general feeling of hydrologists and experts whose articles I've read is that as soon as you try to control water in this way, you're courting disaster. Sooner or later, many have observed, the water always wins.