After drenching the Bay with the greatest amount of fresh water on record during the first six months of this year, the flows have turned to a trickle.
Figures from the U.S. Geological Survey show that during October, flows from the Bay’s tributaries averaged 17, 500 cubic feet per second — about 59 percent below the long-term average of 42,300 cfs that normally flow into the Bay during the month.
From January through June, flows into the Bay had been above average every month. In fact, 1998 had been on track to pass 1996 as the wettest year on record.
But starting in July, flows have been below average every month. In fact, while flows were 60 percent above normal for the first six months of the year, they were 33 percent below normal during the past four months, according to USGS figures.
Overall, the total flows into the Bay for the first nine months of the year remain higher than normal, but with the September flows, this year has fallen behind 1996 as the wettest year since the USGS began measuring flows 48 years ago.
Through the first nine months of the year, according to USGS, freshwater flows into the Chesapeake are about 5 percent less than the same period of 1996 — in large part because September 1996 was extremely wet.
High flows into the Bay contribute to water quality problems by flushing large amounts of sediment and nutrients off the land and into rivers and streams. The nutrients cause algae blooms which, along with sediment, cloud water and prevent sunlight from reaching important beds of underwater grasses. When the algae die, they sink to the bottom and decompose in a process that depletes the water of oxygen.
The USGS has monitored flows into the Bay since 1951. Real-time streamflow data and other information on water resources can be found through the USGS Chesapeake Bay web page at: http://chesapeake.usgs.gov/chesbay/