Denialist Questions Value of Septic Ban

Morris wants proof septics hurt bay

[St. Mary's County] Commissioner Dan Morris (R) told a class of college students on Tuesday that he wants proof that septic systems are damaging the Chesapeake Bay.... He said he questioned the science behind the plan to clean up the Chesapeake Bay. “What good is it if you don’t prove it? Because of this philosophy it’s costing you money,” he said.

Upgrading the 26,701 septic systems in St. Mary’s County could cost $144 million, county staff estimates.

A student asked about the value of a healthy Chesapeake. A septic tank that is working properly, Morris said, “poses no damage to the bay.”
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Todd Eberly, assistant professor in the department of political science at St. Mary’s College, said Wednesday a 2007 study by the Chesapeake Bay Program estimated that of all the nitrogen entering the Chesapeake, about 1.4 percent came from septic tanks in Maryland. And counties in Southern Maryland will have to shoulder a large part of the costs to upgrade its septic tanks.

I've seen higher numbers for septic input of nitrogen into Chesapeake Bay, (more like 7%), but I suspect this one is more likely correct.  If you draw a line across the Chesapeake Bay mouth and measure the water sloshing in and out with the tide, a lot of nitrogen is going to move into the Bay on the tide, even if the concentration at the ocean end is relatively low.  Then, a lot sloshes out on the ebb tide, with a relatively small net effect.  It all depends on how you do your models. Still, eliminating 7% of the nitrogen (unlikely in the extreme, halting new septic development merely keeps it from growing), while an improvement, will barely show in the slop around the nitrogen budget.