Conclusions, recommendations

Conclusions

• Atmospheric deposition is a prime source of nitrogen loading that should not be overlooked. Additional research is needed to identify the contribution of local vs. distant sources of atmospheric deposition.
• Spatial distribution of the development is extremely important for water quality in the estuary. By avoiding land use change in the river buffers (~200 m) we can compensate for most of the development in the watershed even under maximum buildout.
• Even more important are the particular land use practices. Grow trees, not lawns.
• Yet more important are the management practices. The redesign of septic fields, that would deliver the effluent to the root zone, rather than the groundwater, can considerably increase nitrogen retention and improve the water quality of the estuaries.
  
  The existing septic tanks are designed to remove the discharge from the human habitat locally. As a result the effluent is channeled into the groundwater, that sooner or later reappears on the surface. When the groundwater gets contaminated it is much harder to treat. The alternative design instead of burying the nutrients would make them available to uptake by vegetation. The difference is like between storing in a landfill and recycling. The vegetation can benefit from the added nutrient supply, while keeping the waters clean.

Recommendations

• Support further analysis of the pathways of nutrients across the watershed.
• Consider alternative designs of septic tanks and drainage fields, that would make more use of biological treatment.
• Prioritize and implement conservation efforts before further growth outstrips their positive effects.
• Minimize clearing, maximize reforestation and encourage reduced lawn areas.

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