Where does the water go?

Streams are quirky things. They have personalities--no two are alike. Before a doctor can prescribe, she needs to know the patient.

Yesterday, I took a tour of our stream, to see how it was doing. Upstream, by the park, it was burbling along, with quite a bit of water, even though it hasn’t rained for several days. And, the water was crystal clear! It‘s still a living stream.

Then I walked downstream from S. Owen Drive. Still a good flow was coming out of the pipe. But about a third of the way down the ravine, the water disappeared, as it usually does.

So, where does the water go? There are two possibilities:

1) The grade of the stream increases. Possibly the groundwater level here recedes, as the groundwater hurries to get downhill. I’m told that when the sewage lines were laid in the ravine, there was a road. So maybe the groundwater here is running fast through the gravel of the old road.

2) About where the water disappears, the sewage line is running nearby, and probably lower. It’s quite possible that the stream’s water is leaking into the sewage line.

Whatever the cause, the lesson is clear. This stream is fragile. Putting heavy equipment in there, and dumping a lot of gravel for a road, is going to completely destroy the stream. There won’t be any surface flow. Whatever is done, a waterproof liner may be necessary, to keep the water from sinking in.

I also looked for bedrock. If there were solid bedrock, then it wouldn’t be as necessary to protect the stream banks. You could just remove the rubble, and the stream could flow over the rock. I did find bedrock in three places, but it was highly fractured--probably it wouldn’t provide a stable bank, or prevent the water from going underground.

Two places in the ravine where you can see fractured bedrock

The squarish blocks of limestone you find in the ravine could be saved and used as a raw material for terraces or reinforcing the bank.