Saturday, February 2, 2019

Draining Olivers Woods

This fine mild Saturday morning, I went to the Woods armed with knee boots and a hoe. I headed to the sodden southwest corner of the Woods. Water pushed in there months ago by heavy fall rains and run-off from the university parking lots around the arena has never drained or evaporated away. The SW corner has not historically been a wetland. It supports a closed canopy forest of elm, big bur oaks, sugar berry, green ash, persimmon, and others. The roots of these trees can only take inundation for so many days or weeks before they begin to die back and the trees are stressed or killed. I decided I would make small efforts to remove obstructions and increase the flow of the impounded water out of the Woods. This is not normally a good idea in natural wetlands. They should remain flooded as long as they are naturally.
Through the southwest gate and along the main trail I walked only a hundred yards before encountering standing water. I figure if I increase the flow rate by just a little it could have a positive effect over the days before our next forecast rain. There were acres of water, mostly just a few inches deep. I sloshed along through the continuous shallow lake noticing bright green submerged leaves of Polygonum pink ladies thumb, growing luxuriant mats of fine stranded green algae. There were small dime-to-half-dollar-sized floating light yellow 'puffs'.. something growing.. not sure what. There was here and there a fine sheen of oil. I used to take as pollution by petroleum oils, until I realized that natural decomposition of leaves and organics also produces this same healthy sheen.
I walked east and south to the old Beaver Dam. The water there was barely moving through the cut. Downstream the flow was impeded by mats of leaves and fallen trees. I started moving things aside and clearing a foot-wide channel to allow flow. Down by the big willows on the south boundary a large elm had crashed across the channel and blocked the flow almost entirely. I cleared branches and leaves using the backed-up water to assist clearing a channel.
After a few hours there was a clear flow maybe an inch deep. I felt good. That was success. Over the hours and days ahead, that would gradually allow the Woods to begin to drain.. not entirely. There were going to be low areas that held water; but the acres of backed up water could now begin to slowly move out. As I walked out, I thought how just clearing that small a channel a quarter mile away would start to have an effect on the water molecules, the tens of thousands of gallons and the many tons of water backed up to the west. I am sure there will be water remaining all along the trail when the next rains come. But hopefully the water level will be a few millimeters or centimeters lower and roots of trees along the channel may gain a partial benefit.

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