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“There is an indication,” says Scott Phillips, chief of the USGS Chesapeake effort, “as to why we may not see the rivers or the Bay come back as quickly as we hope.”

“The problem is that the speed at which the Bay responds to cleanup efforts may have more to do with the trajectory of a falling drop of water than by actions being taken on the ground today,” reports the Bay Journal. “That drop may land and roll downhill until it, and anything it has picked up on the way, splashes into the nearest stream and begins its journey toward the Chesapeake. It will reach the Bay in a few days. But suppose instead of flowing down to the stream, the drop soaks into the ground. Eventually, it reaches the groundwater, at which point it begins - slowly - to work its way toward a stream, pond, or wetland.

“Someday,- along with chemicals it has picked up along the way – it will reach the Bay. But instead of a matter of days, the journey may take decades. The time from which a water drop hits the ground to the time it works its way through the groundwater and to the Bay is called ‘lag time’. And, at least as far as nitrogen is concerned, the lag time is dampening expectations for a speedy Bay improvement.

“A pair of recent studies from the U.S. Geological Survey’s Chesapeake Bay Ecosystem Program show that about half of the water flowing into the Bay originates from groundwater, which carries about half of the nitrogen that enters the Chesapeake. The studies found that most groundwater appears to take an average of 10 to 20 years to work through soils and aquifers and into waterways. That means the groundwater entering streams today is actually carrying nitrogen it absorbed when rain soaked the groundwater table in the late 1970’s and early 1980’s - long before anyone emphasized nutrient reductions. Likewise, nutrient reduction efforts taking place today will help - but their full effects may not be realized until after 2010.

“Groundwater lag time is a problem that mainly affects nitrogen. Phosphorus, which is more likely to bind with soil particles that control sediment runoff can help keep phosphorus bound up - and out of the water - for decades, if not centuries. Nitrogen, though, is more soluble and is easily carried away either through surface water runoff, or through the groundwater.”

So, the issue for a long time into the future, is what WE do, each of us as we fertilize our lawns, hoping for greener, more luxuriant growth, as we manage our septic systems - or install them inappropriately - because ALL septic systems currently manufactured and permitted according to legal standards - produce nitrogen which goes into groundwater. We COULD, if we WOULD, turn our households into zero discharge systems. We COULD, if we WOULD, stop fertilizing our lawns. The question is, how much do we care



 

 

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