How Much Nitrogen and Phosphorus are Stored in Conowingo Reservoir?
Nutrient samples were collected from the lower third of the reservoir, where the sediment thickness is greatest. On the basis of data from Langland and Hainly (1997) and data collected from previous studies (Hainly and others, 1995; Reed and Hoffman, 1997), about 670,000 tons of total nitrogen and 130,000 tons of total phosphorus remain in the lower third of the reservoir. These amounts are equivalent to about 9 times the annual total-nitrogen load and about 50 times the annual total-phosphorus load transported to the Chesapeake Bay by the Susquehanna River during a year of normal streamflow. How Much Longer Will the Conowingo Reservoir Trap Sediment and Nutrients? Although the Conowingo Reservoir is not filled with sediment, little space remains. Changes in the cross-sectional areas of space available for sediment and nutrient storage from 1928 to 1996 and the approximate level of maximum sediment-storage capacity are shown in figure 4. From the upper end of the reservoir to about 28,
