The Cascades at Birchbank |
LIDAR image showing brooks, recharge ponds, and RR tracks (click to enlarge) |
(As an aside, people often assume there must also be a matching "Lower White Hills Brook." There is not. This is a brook that flows through an old Huntington district called "Upper White Hills." So the word 'upper' describes the district, not the brook.)
One of the smaller recharge ponds. The water level dropped after ice formed. |
Water in the man-made channel along the railroad tracks will make it's way to the first of several man-made groundwater recharge ponds that feed a wellfield operated by the Aquarion Water Company. The wellfield is only used in times of drought, since it's expensive to pump the water out of the ground and up the hill and yonder to Means Brook Reservoir. The recharge ponds were originally designed for Housatonic River water to be pumped in, but are now filled exclusively with Birchbank runoff. Aquarion's pipeline goes straight up the precipitous hill at the trailhead parking lot. Pro tip: Don't try to walk up the pipeline, it's steeper than it looks.
That's how the drainage normally works at Birchbank. There are some smaller intermittent waterways that spill down the hillside to feed the recharge ponds, like the little brook near the bench. But every so often, maybe once or a few times a year during the rainy season, we'll have a lot of rain when the recharge ponds are already full and can't take any more water. At that point, the excess water runs south down a man-made channel at the base of the railroad tracks to an old culvert that crosses Indian Well Road and the tracks near the trailhead. It's right where the road crosses the tracks.
This old culvert channels floodwaters across Indian Well Road and the tracks |
And then, during an exceptionally rainy day last week (maybe 4" on top of saturated ground), we were sent the picture below:
Birchbank Trail. That's not good. (Photo from Ted) |
We had never seen the water that high. In the past, it never even got up to the trail, and now it was a foot or two deep on the trail. A few hours later, the water had receded by about a foot, but was still up to the top of the old stone culvert and swirling into it with great force and (photo below).
Flood waters going into the culvert |
As we suspected, when the flood waters dropped, there were some logs, branches, and leaves clogging up part of the culvert. Once the water level receded to a safe level, the clog was ripped apart, and backed-up water really gushed into the culvert.
Yup. The culvert is clogged. (Photo about 1 week after the flood) |
All cleared! |
This is the same view point as the previous flood photo |
The culvert. Wow. |
But the trail isn't flooded. It's a normal flood. |
It was surprising how much water was flowing through the culvert considering the channel was bone dry the day before. Good thing the log had been cut up and carted away the day before, or it would have been blocking the culvert again. At any rate, we're now aware that we should be checking that culvert routinely or the trail can get flooded.