Plan for Preventing Localized Biological Oxygen Demand (BOD)
As pointed out in Section ____ of the text of this amendment, a major nutrient
enrichment from decomposition of waste feed and feces from the marine aquaculture
facility could create localized BOD if the facility is not properly sited. Major siting
criteria that have an effect on whether such BOD is easily dissipated without serious
environmental effect or creates a problem, mainly consist of location, current patterns and
depth of water at the facility and its proximity to other facilities. The operational
activities that affect the environmental significance of the BOD include total biomass of
fish that will be raised at the facility, the total biomass of feed utilized daily, composition
of feed, and the type of culture system utilized. For example, cage or pen culture will
result in the BOD developing down-current from the facility at a distance dependent on
the current speed. Bottom culture facilities utilizing feed would likely create a BOD very
near or including the culture area. Current speed is the major factor. For example, a
current flow of 20 cm/second would create at least 1,728 water exchanges per day for a
cage 10 m. in diameter, or a flow of 2 cm/second, 173 water exchanges daily.
At minimum the plan for preventing localized BOD should specify or include:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Water depth and location of the facility;
Range of current speed at the depth the culture system will be deployed;
Range of biomass of feed that will be utilized monthly at the facility from start to
conclusion with each culture period;
Composition of the feed;
Type of culture system that will be deployed;
Anticipated increases of fish biomass produced monthly during each culture
period; and,
Specification of the water quality monitoring system that will be utilized and
frequency of sampling.
H:\A\Aquaculture\Preventing BOD.doc