If the Bay states were to pull out all of the stops and get everyone to implement every nutrient control practice they know how to do, everywhere possible, they could achieve dramatic nutrient reductions.
It would not restore the Bay to the condition that Capt. John Smith may have seen when the entire watershed was forested, but it would slash the amount of nitrogen entering by two-thirds from mid-1980s levels, when efforts to clean up the Bay began.
Similarly, it would reduce phosphorus to about 60 percent of its estimated 1985 level.
The problem is, officials believe the estimates are probably unreachable, at least in the near future. The hypothetical scenario is dubbed “E3” for “everything, everywhere by everyone.”
Among its assumptions:
- All new septic systems would include nitrogen control technologies that reduce nitrogen in effluent to 10 mg/l. (Raw sewage usually has a nitrogen concentration of about 30 mg/l).
- All existing septic systems would be replaced with nitrogen control technologies that reduce nitrogen in effluent to 10 mg/l.
- Wastewater treatment plants would reduce nitrogen in effluent to 3 mg/l, and phosphorus to 0.1 mg/l. (Traditional wastewater treatment typically reduces nitrogen concentrations to a bit more than 20 mg/l, while current nitrogen control technologies reduce that to about 8 mg/l.)
- Industrial facilities would reduce nitrogen discharges by 85 percent.
- The rate of development would be reduced by 30 percent.
- No fertilizer would be applied in urban and suburban areas.
- All new development would use environmental site design and low-impact techniques to reduce runoff.
- All old urban areas would be retrofitted with stormwater control practices.
- Almost a fifth of all farmland in the watershed would be taken out of production and enrolled in the Conservation Reserve Enhancement Program.
- All farmlands would have forest buffers. Pasture lands would have 100-foot forest buffers, and streams in pastures would be fenced to keep out livestock.
- 25,000 acres of wetlands in the watershed would be restored (fulfilling a Chesapeake 2000 commitment).
- 25 percent of all remaining cropland (after CRP and buffer programs) would be used to grow carbon sequestration and bioenergy crops, such as switchgrass, which require few nutrients and yield little sediment or nutrient runoff.
- All cropland and hayland would be in a “yield reserve” program that pays farmers to use less fertilizer than recommended in a nutrient management plan.
- 100 percent of excess animal manure would be used for alternative uses.
Officials consider the scenario, thought to be the theoretical limit of technology, to be unachievable. Among the problems is that there is not be enough physical space to implement all of the “E3” actions.
For example, even if tens of billions of dollars were available to retrofit all urban areas with stormwater management programs, there is not enough space for the needed retention ponds, buffers and other controls.
Likewise, 100-foot buffers could not be placed along streams — in many places there is not enough room.
“Clearly, that is not realistic,” said Mike Bowman of the Virginia Department of Environmental Quality, who chairs the Bay Program’s Tributary Strategy Workgroup. “But it does apply current technology to the fullest possible extent.”
Still, while “E3” looks impractical today, it doesn’t necessarily mean it is not attainable in the future. Technologies change, officials note, and what is not feasible today, may be tomorrow. Potential levels of nutrient controls being considered today are near what was considered to be “limit of technology” a decade ago.