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Caption: This chart shows total phosphorus levels at five Sheepscot River watershed sites during six sampling dates in summer/fall 1999, with Sheepscot stream flow at the USGS gage overlaid as a thick blue line. On September 11 the season's first rainstorm increased streamflow to 179 cubic feet per second (cfs) from 32 cfs a day earlier. At the same time, total phosphorus levels rose substantially at all sites except the mainstem Sheepscot at Route 17 (above the confluence with the West Branch), thought not nearly as dramatically as nitrate levels did (see other topics for nitrate charts). By September 30, streamflow had diminished and total phosphorus levels had decreased back to near baseflow levels. Data were collected as part of the Maine Department of Environmental Quality's baseflow water quality sampling.
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