receives more than its "natural" supply of nitrogen then, as was 
mentioned earlier, it was worse than "the natural situation." I 
say this because of the tremedous reserve of nitrogen in the 
bottom sediments, improvements due to reduction of the nitrogen 
supply will take an appreciable length of time to become 
apparent. 
I'd also like to reinforce the point made earlier concern¬ 
ing the variability of the extent of anoxia. Stratification, a 
physical phenomenon, is very important in determining how early 
it develops and how long it lasts. During the high inflow sum¬ 
mer of 1984, stratification developed early and was strong 
throughout the season. USGS observations have been that anoxia 
was much more extensive during 1984 than in the summer of 1985, 
which was a low-flow summer. 
The remainder of this presentation deals with conditions 
developing now in the tidal river which have a potential to 
radically alter the nutrient budget picture just presented. 
Since 1983, there has been a major resurgence of the amount of 
submersed aquatic vegetation in the tidal river. Between each 
of the summers 1983 to 1984 and 1984 to 1985, there has been an 
approximate ten-fold increase in the amounts of submersed 
aquatic vegetation growing in the tidal river. 
The U.S. Army Corps of Engineers, calculated that the 
plants have the potential to cover 33,000 acres in the tidal 
fresh part of the Potomac River. This is about two-thirds of 
the river bottom between Quantico and, say, Haines Point. The 
plants may be present from as early as late May through mid- 
November. Considering the 33,000 acre figure and using pre¬ 
liminary estimates of the density of the biomass cover from 1985 
USGS submersed vegetation surveys, one can conclude that the 
biomass that could be produced is on the order of ten times what 
was contained in the algae bloom of 1983. This is a significant 
amount of biomass and it could have quite a major effect on the 
water quality conditions in the river. This biomass would tie 
up a 12 to 40 day (depending on which author's figures on how 
much phosphorous is contained on the average in these plants) 
supply of the sewage treatment plant supplied nitrogen and a 30 
to 150 day supply of the sewage treatment plant supplied 
phosphorous. Again the potential to significantly impact the 
water quality conditions is obvious. 
The plants also significantly alter the water s clarity. 
In areas where there are large patches of vegetation, the bottom 
is clearly visible in 5 feet of water. Whereas, in earlier 
years, visibility was limited to a few inches. There has also 
been a major change in wildlife in this area; large numbers of 
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