02
Aug

If you’ve taken a walk in lower Frick Park recently, you’ve undoubtedly noticed the unusual amount of trash and debris scattered around the flood plain and dangling from trees and shrubs, as well as some significant erosion of the walking trails.  I’ve been working with the Watershed Association for more than 11 years, and I can honestly say conditions are the worst I’ve ever seen in and around the restored stream, with the possible exception of June 18, 2009, the day after a particularly intense storm system rolled through. This time there is not just a single storm system to blame.  Instead, what you are seeing is a graphic manifestation of how climate change is impacting our region.

For years the accepted average amount of annual rainfall in Pittsburgh was 37.7 inches – and if you ask Google, that is still what you will find. But in 2017 we had 40.6 inches, and last year the total was an extraordinary 57.8 inches. This year, the rain gauge at the bottom of Nine Mile Run had already recorded 37.1 inches by July 31st. So we will almost certainly exceed 2017’s total this year, and may come close to another record year.   Not only are the totals higher, but the way the rain arrives has changed as well. Only a few years ago, a summer thunderstorm “tropical downpour’ would last for just a few minutes, and then it would gradually taper off to a more moderate rate, or even stop altogether. Now we frequently experience intense downpours that last for 30 or 40 minutes, or more. 

Blue shopping bags dangle from branches along the stream

What’s going on here? Well, it’s pretty simple. Warmer air holds more water vapor, and eventually that will find its way to earth as snow, sleet, rain, or hail. And as anyone who hasn’t been living in a cave knows by now, our temperatures are getting warmer, both here in Pennsylvania and globally. Worldwide, the five warmest years on record were the past five years — and the 20 warmest occurred over the past 22. The warmest year on record for the earth’s oceans was 2018.  Every time that a weather reporter uses words like “record-breaking”, or “unprecedented” to describe a weather event or disaster, that should be followed by an explanation that these are exactly the kinds of events that climate scientists have predicted for decades and that we should expect as the earth warms.

As we explain at all of our stream sweeps, since much of the watershed has separated storm sewers, heavy rains carry any trash on the streets into the storm sewers and directly into Nine Mile Run, during major rain events, the stream spreads out across the flood plain, which is exactly what was intended in the re-design of the stream when it was restored between 2003 and 2006. But this year’s storms have carried more trash, and deposited it over a wider area, than ever before.  While it isn’t safe to be in the middle of the valley during one of these prolonged intense storms, you can find out later how high the water got by just looking at where the plastic bags and other debris are hanging from the trees. 

Toilet paper and trash bags hang from tree branches across the flood plain

One of our core missions here at the Watershed Association is to steward the NMR restoration area. In addition to our annual Spring and Fall Stream Sweeps, this year we will be scheduling some additional clean-ups to deal with the “unprecedented” amount of trash we are facing.  Follow us on social media for announcements of when these will be happening if you’d like to help out. We’ll also keep working on better stormwater management solutions in the upper watershed communities to try to reduce the overall burden of flooding that the stream now faces on a regular basis. If you already have a rain barrel or rain garden, or a street tree in front of your house, THANK YOU!! If not, and you are interested in getting involved to help solve the problem, give us a call.

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