I went out in yesterday’s rain storm to look at some of the stormwater practices Columbia Association (CA) has installed and to see how they were working. Thanks to live weather radar, I could see the line of storms moving toward us in the afternoon and tried to time it so I would arrive with the rain.
My first stop was at a couple of rain gardens installed through our cost-sharing program. I arrived before the heavy rain began, but they had been getting showers all morning. They looked great. But I wasn’t going to be able to wait and see how they handled a heavy rainfall, had to move on.
My next stop was the bio-retention facility at the Lake Elkhorn Park parking lot. The facility is designed to slow the flow of runoff from the parking lot and let it soak into the ground instead of flowing straight into Lake Elkhorn. The sky was dark gray as I arrived, and there was only one car in the lot.
The facility is really just a big rain garden. There was a little water in the bottom when I got there, not much runoff, yet. The heavy rain came as I stood there, and it poured buckets.
I continue to be amazed at the use of the path around Lake Elkhorn. As I stood there in the pouring rain, two runners went by. We didn’t acknowledge each other; it was almost awkward. I’m sure they were thinking the same thing I was: “Really?”
Then it happened. Most people never get to see it, so I thought I’d share. About five minutes into that downpour, enough water had fallen that the parking lot began to generate runoff. I snapped a picture of the leading edge of the flow as it moved through the rip-rap channel that leads to the bio-retention facility.
The facility began to fill, and within 10 minutes there was a pool of water. So it was working, slowing the flow and allowing it to soak into the ground.
I’d seen what I came for at Lake Elkhorn. My next stop was Homespun Drive. The bio-retention facility on Homespun treats parking lot runoff before it reaches Homespun Pond. By the time I got there the rain had slackened and the facility was almost full. There was a small stream of runoff coming off the parking lot and flowing into the facility. Next stop: Wilde Lake.
By the time I got to Wilde Lake, the rain had stopped and most of the runoff action was over. It wasn’t really over, there wasn’t any more being generated, and what had been generated had moved across the landscape and collected in our streams. There were pools of water where drains were clogged, and the leaves and debris showed where the runoff had flowed. I went to another rain garden to see how it had held up. This rain garden is picturesque and treats roof runoff and runoff from lawns that flows directly into Wilde Lake. The garden had filled and there had been a little erosion at the point where the garden overflows, but other than that it looked pretty good.
Then I heard it: the roar of rushing water. Lots of rushing water. It was not as loud as some I have heard. I saw Conowingo Dam during the flood caused by Tropical Storm Agnes, and that was like continual thunder. So, like a moth to the flame I walked to the lake’s edge and looked toward the point where the creek that feeds Wilde Lake flows into the lake. The creek was roaring as it entered the lake, there were small standing waves and swirling eddies, and the lake was turning a chocolate brown. I guess it was reminding us that the process that created the sediment deposit we just removed didn’t stop or even take a break. It just keeps delivering sediment. It is going to take some work to slow that flow.
-Written by John McCoy