The Chesapeake Bay and its tidal waters are impaired by amongst other things the release of excess nitrogen, phosphorus and sediment. These pollutants are released from waste water treatment plants, from agricultural operations, urban and suburban runoff, wastewater facilities, air pollution and other sources, including septic systems that enter the tributaries and Chesapeake Bay. These pollutants cause algae blooms that consume oxygen and create dead zones where fish and shellfish cannot survive, block sunlight that is needed for underwater grasses, and smother aquatic life on the bottom. The US EPA has taken control of the situation and has developed a new federally mandated TMDL to restore the Chesapeake. The total maximum daily limit, TMDL, allocates a pollution budget among the states which will decrease over time.
The plan to meet the federally mandated TMDL is called a Watershed Implementation Plan, WIP. The six Chesapeake Bay states and the District of Columbia were required to develop WIPs to meet the federally mandated TMDLs. The EPA found Virginia’s WIP to have serious deficiencies. It did not meet allocations for nitrogen (6 percent over the limit) and phosphorus (7 percent over the limit), but did meet allocations for sediment (12 percent under the limit). In addition, the EPA found that the Virginia WIP relied on pollution trading programs but had no commitment to adopt new regulations relying instead on market forces. The EPA deemed the WIP to be vague and contain limited enforceability and accountability for filling the gaps identified by the EPA. The federal government will require Virginia to reduce their nitrogen release by an addition 12 million pounds per year, and their phosphorus release by 1.7 million pounds per year beyond those identified in the WIP. EPA has made it clear they will enforce reductions in the areas they can control under federal law to meet the TMDL. The EPA can only mandate reductions in waste streams from waste water treatment plants, CAFOs (concentrated animal feed operations), municipal separate storm sewage systems, MS4s and wastewater treatment plants.
To ensure that Virginia meets the TMDL goals the EPA will squeeze the MS4s, CAFOs and waste water treatment plants possibly beyond the economically feasible limit to get what they want. The EPA wants Virginia to develop a set of regulations for land use that will meet the TMDL. The Chesapeake Bay TMDL will force changes in how each of us lives, the costs for building new homes, hospitals, businesses and roads, the costs for repaving roads and redeveloping areas, the costs for building and operating a septic system, the cost of public water and sewage and taxes. That is the price of growing population density and a healthy and sustainable Chesapeake Bay. About half the land and 60% of the population of Virginia is within the Chesapeake Bay TMDL.
The first TMDL to be developed for Prince William County, Virginia (where I live) is for Cedar Run. The Cedar Run watershed is the land area that drains into Cedar Run and includes much of Nokesville. The nearly 87,000 acre watershed continues into Fauquier County. While EPA and environmental groups have emphasized the contribution of agriculture in the form of CAFOs and waste water treatment plants, the reality is that only a portion of Prince William County is serviced by the HL Mooney a WWTP and the Daly City units and the county only has two working dairy farms left. These days the horse farms greatly out number the beef cattle operations. Golf courses and suburban development are increasingly the sources of nutrient and sediment contamination in the watershed. The state and county is going to have to increase regulations on hobby horse farms, golf clubs and suburban developments. In order to meet the TMDL for the watershed changes will have to be made. No area will remain untouched by regulation.
For example along with the issue of backyard chickens, the county will have to readdress the zoning for horses. The keeping of a single horse produces approximately 45 pounds of manure per day, and depending on the type and amount you use, bedding can add another 20 +/- pounds of waste a day. If the horse was kept turned out year round (in our area that would require approximately 3-4 acres of open field per horse) then the horse would not be using bedding, which accounts for an addition 50% of the waste and the open acreage could serve as a solution to what to do with the manure. That single horse produces approximately eight tons of manure each year that would be "spread" by the horse at a rate of about two ton per acre per year. Spreading manure at this rate probably will not overload the plants or cause water quality problems through runoff. However, if the property lacks adequate field to keep the horses turned out, then the waste from the sacrifice area and paddocks needs to be managed to prevent excessive nutrient runoff and contamination of ground water. One of the things that will have to be addressed in future regulations is the open acreage requirements for horses.
Septic systems are another area that will have to be reexamined. Dutchess County New York did a study to monitor the nitrate concentrations associated with septic systems. They chose to use nitrate concentrations at half the drinking water level as a proxy for adequate dilution and natural attenuation of all contaminants. Historically, little thought was given to the dilution for wastewater components like nitrate and phosphorus in developing septic regulations. The NY Department of Health separation distances were assumed (and these are almost identical to the Virginia setbacks), but the overall regional density of septic systems was examined to ensure that groundwater and surface resources would not be overwhelmed by the total load of contaminants. The density recommendations were developed based on the nitrate concentrations. Nitrate was used as a proxy because all humans produce nitrate, it does not easily break down and there is a drinking water standard. The study found that overall average density of on-site waste disposal should not exceed one unit per 2-3 acres for an average size household to ensure water quality. In many neighborhoods septic density is much greater than one unit per 2-3 acres. In the WIP Virginia is beginning to address the possibility of requiring nitrate removal technology in new and repaired septic systems.
The county is currently considering a proposal to allow backyard chickens in residential areas. According to the Delaware Department of Natural Resources and Environmental Control, the typical household generates 10-15 pounds of nitrogen per year and 1-2 pounds of phosphorus per year. According to a Maryland state study, each chicken generates approximately 0.41 lbs of Nitrogen per year and around 0.35 pounds of phosphorus per year. Thus, each household with 10 chickens would generate 4.1 pounds of nitrogen and 3.5 pounds of phosphorus per year. This is a significant increase in the nutrient load of a typical house hold, a more than three fold increase in phosphorus load and an increase of nitrogen load by more than 30%. This additional waste is delivered in an uncontrolled manner to the surface. The poor location of a chicken coop could potentially impact ground water and well heads both on and off site and subject to runoff. Before Prince William allows additional nutrient loads they need to address reducing the current source of excess nutrient pollution.