Earlier this week I was in Panther Hollow on a warm, sunny afternoon. It hadn't rained substantially in a few days and it really showed.
The pale touch-me-not that happened to be in the sun was quite wilty. This plant was obviously not enjoying the hot, dry weather, but in fact it is doing just what it needs to do to survive. If you look closely you will notice that the leaves are folded over so that less of their surface area is in the direct sunlight. Nearby plants in the shade were not wilted, including those that had been in the sun earlier that day. I also noticed similar wilting during the big heat wave a couple of weeks ago, and they went right back to normal after it rained again.
I went to check on Panther Hollow Run and noticed that there was very little flowing water. In fact, in one section there was no surface water at all!
Is this normal?
It is not unusual for small streams to dry up during periods between rainfall. However, my guess is that before the stream was beheaded, summer dry spells seldom, if ever, caused this section of creek to dry up completely. Some water that falls in the upper watershed and soaks into the soil probably seeps into the lower creek all year, but summer rain tends to be heavy and brief, and most rain that now falls on Squirrel Hill hits a rooftop, pavement, or an area of compacted soil and quickly washes into the sewer system instead. In addition to reducing sewage overflow into the Monongahela River during storms, installing rain gardens, bioswales, and permeable pavement in Squirrel Hill would probably reduce the likelihood of this creek drying up. Measures that the Pittsburgh Parks Conservancy is taking to increase absorption of water that falls on the golf course are also likely to help. Since some aquatic animals such as fish and certain amphibians die when a creek dries up, reducing the amount of Panther Hollow Run that dries up each year would probably lead to an increase in the number of animals that use the area. Besides, it's just nicer when there is more water in the creek during hot, dry days!
The low water levels in the creek and in Panther Hollow Lake made it a lot easier to see the 'delta' that has formed in the lake due to sediments being washed in from erosion occurring in the park.
I always have thought that it is really neat how a small creek can make landforms of the same shape and scale as a huge river. In this case, however, the delta is not desirable because it is resulting in Panther Hollow Lake slowly filling up with sediment.
Near the lake I found an area where someone decided to help the park do environmental education.
It was nice to know what I was looking at, in case I became confused after also finding rocks and dirt in the area.
The creek may not have had dry stretches for very long in this case.
A few hours after I visited the creek thunderstorms moved through the area. The above storm dropped only a few drops of rain but other storms later in the day dropped much more. The Pittsburgh airport reported about .37 inches of rain that evening and the next day. It appeared that it may have rained more at Schenley Park than at the airport, though. I didn't get a chance to see if the creek was flowing after those rains, but I am hoping to spend more time getting rained on in the park before I go back to Vermont.