The importance of shore protection in the Watershed Plan

The Engineering Dept. has already committed to a three-year study of the Lake Wingra basin, with the aim of improved planning and coordination of management.  The Plan should include shore protection.

Shore protection--essential for water quality

One essential for water quality has long been recognized in Madison--reducing the input of nutrients and mud to the lake.  More recently, it's been recognized that controlling stormwater is also essential.  This boils down to infiltrating most of the rain where it falls--with rain gardens or pervious pavement.

But there's a third essential that's mostly been forgotten, because we live in a city where much of the shore is privately owned.  And that's protection of the shoreline itself, including the banks of streams that feed the lake.

Shoreline protection is vital because it's an area under assault--from wave action, wildlife, and intense human activity.  At the shore, any erosion feeds sediment directly to the lake.  Once started on the busy shore, erosion is very hard to stop.

The natural buffer

I first became aware of the importance of the natural ring of vegetation when I volunteered to help protect Hawksnest Pond in Massachusetts.  At this pristine pond, the water is crystal clear, thanks to a buffer of vegetation that's intact around the entire pond.  Not a drop gets into the pond unless it falls on the surface, seeps in through the sandy soil, or is filtered through a thick mat of shore vegetation.

Click to enlarge photos

Hawksnest Pond is like LakeWingra 150 years ago.  But in Madison, there are few areas of natural shoreline left to remind us of the importance of this buffer.

Shoreline vegetation not only prevents erosion--shade also helps keep the water oxygenated, provides wildlife habitat, and presents a more pleasing view from the water.

Once invasive species get established on eroded banks, they can easily spread via the water.

In Madison--more effective shore protection is needed

Here are some recent examples, showing that current policies don't protect shorelines and waterways:

North shore of Lake Wingra, 1/3/11.  Some native shrubs were cut.

This strip is owned and managed by owner of the house.

Riprapped channel below Glenway Golf Course.  A complaint about erosion nearby caused City to cut vegetation along waterway. 

Left: Before; right: during cutting (Credit: L. Coleman).

Caving bank 25 feet high, on Lake Mendota at future site of Edgewater Hotel reconstruction. Summer, 2010.

Erosion along creek feeding L. Wingra, near Nakoma Rd and Cherokee Dr, 6/9/08.

Because the Lake Wingra's shore is mostly protected by parks and wetlands, shore protection is a minor issue here.  Nevertheless, because the Watershed Management Plan will be a model for other watersheds where shore protection is a bigger problem, we need to start with Lake Wingra.