Sunday, October 11, 2009

The shoreline--a fragile filter

Imagine that you are brewing a nice cup of coffee, using fresh grounds heaped in a paper filter. Normally, the water flows through, and the grounds stay back, so you have a clear, tasty cup of java. Now imagine that when you pour the water in, the filter breaks! Your cup is filled with bitter grounds, the brew is cloudy, and your morning treat is ruined.

We're faced with the same issue at Hawksnest. The thin veil of vegetation around the lake, and the sand below, is our filter. Normally, no water gets into the lake without flowing through the vegetation and sand.

The lakeshore is especially important. Whereever the shore is undisturbed by man, thick vegetation grows right to the water, holding back and filtering any runoff from a heavy storm. This is why Hawksnest is so incredibly clear--a pond where you could see right to the bottom, 30 feet down. Coastal plain ponds like Hawksnest are actually quite rare--despite the fact that we take them for granted on Cape Cod.

When people, horses, or vehicles trample the bank, the filter is broken, and soon our pond will be ruined, just like the java.
Severe erosion on path to beach from Round Cove Rd parking area

Protecting this fragile filter all around the lake is probably the most important management goal for the entire park. It's essential if the unique quality of the pond is to be preserved. Yet the shoreline vegetation has been neglected, until erosion has finally reached the point where serious, lasting damage is about to occur. Protecting the shore at Hawksnest is all the more important, because the shores of most other ponds have been severely damaged.

The shore of a pond like Hawksnest is the only place where the Plymouth gentian grows, a plant of special interest, which property owners (the State included!) are required by law to manage for. Common sense management requires keeping people, horses and vehicles off the beach where the gentian grows.

No, I'm not saying "no swimming." For the gentian, just post signs limiting access to certain areas.

Where serious erosion of the "fragile membrane" is occurring at the Round Cove parking lot, control of erosion and restoration are urgently required. In the long run, the only way to prevent further damage to the pond's shore is to build a boardwalk where many people tread down to the beach .

Because of the humid air and mild climate, the land will heal itself in only a few years, if given the opportunity.

Boardwalk, National Seashore, Provincetown. Our boardwalk might use wire mesh, to allow vegetation to grow underneath.

No comments:

Post a Comment