Estuarine
Eutrophication
Solutions
Coming to grips with the modifications required to resolve Coastal Embayment Eutrophication entails items that vary widely in cost and complexity. The list below is intended to stimulate thought and is not intended to be complete.
This Mashpee River picture's center shows a medium sized algae mat with
smaller siblings nearby. The lighter colors along the upper edge show tide
deposited mats killing the underlying marsh.
Embayment channel improvements to increase tidal flushing and thereby
reduce inner embayment nutrient residence time and its impact should be
considered. Benthos sediment removal would make a beneficial reduction in
regeneration which is a major source.
Marsh restoration and maintenance
is required to reverse the
continuing loss of this nitrogen consuming structure.
Shellfish population improvements, especially oysters, enhance water
quality. These filter feeders remove huge amounts of suspended algae and
they taste good also. (editorial note)
Wastewater Treatment in advanced nutrient reducing facilities appears
to be a way to reduce wastewater inputs. The complete solution entails returning
the treated effluent to a location that doesn't tie into the embayment
watershed. Alternatively, higher more expensive levels of treatment are required
when discharging treated effluent witjin the watershed.
Atmospheric deposition settles as dry particles or mixed with precipitation.
The sources can be local or distant and are difficult to define accurately
although power plants are known contributors. Reductions at the sources are
usually beyond local control at the embayment level. Atmospheric
deposition falling on vegetated surfaces stands a good chance of being captured
by the plant root systems, while fallout directly on the estuarine surface see
no impediments. Wet deposition becomes stormwater typically commonly described
as run-off.
Run-off or Stormwater contains nutrients from atmospheric
deposition, automobiles, birds, pets, etc. Paved areas, such as roadways,
sidewalks, parking spaces and driveways combined with rooftops create an
impervious collection surface for contaminant containing water that flows
overland or in the groundwater to our estuaries. Actions that minimize
unvegetated land surfaces and stormwater treatment systems such as vegetated
swales upstream of storm drains can reduce this impact.
Fertilizers accidentally
spread on impervious surfaces become a component of run-off. However the
leaching of water soluble fertilizers through plant root zones and into estuary
feeding groundwater is the most significant pollution contributor. Reduced use
of fertilizers and / or the use of low-solubility fertilizers should become a
common goal.