Environmental Commentary by Tom Horton
For centuries, artists, writers, scientists, politicianseven lawyershave drawn inspiration from the Patuxent River, the Bays seventh biggest tributary.
Its tidal marshes are portrayed unforgettably in Gilbert Klingels classic 1951 book, The Bay; its waters and southern Maryland culture immortalized in the lyric of singers such as the late Tom Wisner and the Norris brothers, David and Joe.
The rivers crystal waters in the 1830s moved novelist James Hungerford to make Clearwater River the setting of his novel The Old Plantation.
The rivers murky waters by the early 1970s led Bernie Fowler, a Calvert county commissioner and state Senator, to begin his famous annual wade-in, looking to see his toes as he did in his youth, advocating for cleaner water.
The Patuxent was subject of an unprecedented lawsuit that by 1981 forced Maryland and EPA to recognize nitrogen as a major pollutant, setting the stage for the Chesapeake cleanup.
All this tribute for a tributary; but maybe the most important for the rivers future will be Nutrient Budgets and Management Actions in the Patuxent River Estuary, Maryland (2008), a paper you might have missed it if you dont get the journal of the Coastal and Estuarine Research Federation.
The papers eight scientist authors were led by Walter Boynton, whos lived most of his adult life around the Patuxent. They represent collectively a couple centuries of studying the Chesapeake and how it works.
I use their little masterwork on nutrient budgets every year with environmental studies students at Salisbury University; because what Walt and crew say is vital for restoring most Bay rivers, and the Bay.
Nutrient budgets are simple in concept. They account for everywhere nutrients (nitrogen and phosphorus in the Bays case) come from; and where they go, down pathways that can be bad (like murking up the water and exhausting aquatic oxygen); or good (like gassing off nitrogen into the air or burying phosphorus deep in the bottom sediments). A good budget is the first step to managing for a healthy balance of nutrients, critical to healthy rivers.
But in reality few places anywhere else in the world have budgets of this quality. Most waters havent had major laboratories like the University of Marylands located on them for close to a century, havent had the extensive ecosystem measurements that ground the Patuxent work.
The Patuxent paper examined 13-years of data, covering a period before and after large and expensive upgrades of sewage treatment plants; a period long enough to capture the huge variation in polluted runoff from farms and developments from dry (less pollution) to wet years.
The budget documented that even though high tech upgrades to sewage plants dramatically drove down sewage pollution, , wetter weather and thus higher nutrient runoff from the land, post-upgrade, actually made water quality a little worse.
Wetlands along the river are skimpy, about 12 square miles in a thousand square mile watershed; yet they take out some 700,000 pounds of polluting nutrients annually, an unexpectedly large contribution.
But the biggest way the river absorbs nutrients is in its bottom sediments. Its likely, the scientists write, that when the Patuxent was more alive with seafood and aquatic plants, more nutrients were absorbed by living tissue than in dead sediments. A more stable environment would have been the result, with nutrients less likely to be quickly recycled from sediments to fuel excesses of floating algae.
Hope lies in the papers finding that the bottom sediments arent some inexhaustible reservoir of nutrients that would haunt the river even if we cut new pollution bigtime.
Indeed, water quality improved quickly when dry years reduced new pollution; and as oxygen improved, the sediments released their nitrogen harmlessly back to the atmosphere, which improved oxygen more, which released more nitrogen...a sort of vicious cycle in reverse, Boynton says.
The paper tells us we can encourage that cycle if we:
Apply high tech to what comes from pipes; but also get a handle on land runoff and fallout from dirty air (which already shows signs of improving);
Protect wetlands, which pull way more than their weight in pollution removal;
Understand the rivers problems are largely independent of the bays and dont wring our hands waiting on cleanup elsewhere to restore local waters;
Persevere—evidence shows the system responds rapidly to pollution reductions.
The latest cleanup plans for the Patuxent recognize the papers findings. But achieving whats needed will require all technology can offer, plus unprecedented reductions in runoff from farming and development. This papers not easy reading, but itll tell you volumes about how this estuary works, why its still unhealthy, and how it could recover.
Tom Horton has written several books about the Chesapeake Bay. Distributed by Bay Journal News Service.