I made two trips to Huntley Meadows Park last weekend. On Sunday, I worked with the RMV team to plant (mostly) trees and shrubs (mostly) around the new outdoor classroom, just across the entrance trail from the visitors’ center. I planted two viburnums, two beeches, a blueberry bush, and a Christmas Fern.
Saturday I got an update from park staff on the planned wetland restoration project, which has been scheduled to start construction Real Soon Now for several seasons. The new plans call for a composite design for the dam, anchored by interlocking panels of vinyl sheet piling, with riprap on the downsteam face and a gentle earthen slope on the upstream face. This idea was suggested by National Wildlife Refuge managers, who know something about engineering water impoundments. To deceive the beavers (a beaver never met a course of running water that he didn’t want to dam), the design uses Clemson water levelers to collect the water that will flow through the structure.
Soil science word of the day: it’s the lean clay layer (clay with low plasticity) lying just under the surface that is responsible for keeping the wetland a wetland. If this layer were to be disrupted, it wouldn’t matter how clever the design of the dam was.