Saturday, May 08, 2010

Severe Nutrient Loading at China Lake Outlet Stream, Winslow, Maine, October 2010.

The above photos were taken in China Lake Outlet Stream at the Garland Road Bridge in Winslow, Maine in October 2010 showing extremely thick growths of filamentous algae growing in the stream bed.

This area is about 100 yards above the confluence of China Lake Outlet Stream with the Sebasticook River. The stream here is shallow and fast moving, which discounts the Sebasticook River itself as being the source of the nutrients encouraging the algae growth. This algae is growing in stream water solely from China Lake Stream.

This type of algae growth, especially at this density, is not due to naturally occuring conditions. From our understanding and experience, filamentous algae growths like these in a fast-moving stream are indicative of a nutrient surplus of nitrogen or phosphorus or both. These algae growths suggest a possible contribution of the Kennebec Sanitary District (KSD) wastewater discharge, located several miles upstream in East Vassalboro, in addition to non-point source inputs along the stream (cow manure, faulty septic systems, lawn fertilizer, etc.).

As you can see in the photos, the growths are so thick that they are destroying most of the aquatic insect and fish habitat in the stream where the algae is growing. This stream reach should be (and could now be) Atlantic salmon spawning and juvenile rearing habitat. There are now Atlantic salmon documented to be ascending the Sebasticook (4 large adults were passed at Benton Falls Dam in 2009). These salmon and their offspring are protected as endangered species under the U.S. Endangered Species Act.

Earlier in 2009, in September, on a field trip a mile farther upstream to examine a streamside archaeological site, myself (Doug Watts) and Bruce Bourque, chief archaeologist with the Maine State Museum and Bob Doyle, retired Maine State Geologist, observed similarly thick growths of filamentous algae in the streambed.

An open question is whether the manipulation of outflows from China Lake, now regulated well above its natural levels to provide sufficient 'dilution' for the KSD wastewater, is contributing in some way to this stream degradation. We are now looking into this.

Here are two stills from the video, shot in September 2009. The streamers of algae are about 6 feet long. Unpolluted streams do not have algae growths like this.

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