In environmental management, practices used to prevent water pollution and other negative environmental impacts are called best management practices and usually are referred to as BMPs (Hairston et al., 1995).
A BMP is considered to be the best available and practical means of preventing a particular environmental impact while still allowing production to be conducted in an economically efficient manner.
The word ‘‘best’’ is not intended to imply that a particular BMP will always be the best practice.
The ‘‘best’’ practices must be selected based on site characteristics, and as technology advances, BMPs must be revised to reflect new knowledge. Some workers do not like the term BMP and insist on referring to good management practices (GMPs) or better management practices.
Nevertheless, the term BMP is acceptable terminology in environmental management, and its use should be encouraged over GMP or other acronyms. It should be emphasized that a BMP is seldom applied alone. A system of several BMPs usually must be installed to prevent water pollution and achieve resource management goals.
There has been widespread application of BMPs in traditional agriculture to prevent soil erosion and resulting turbidity and sedimentation in streams and other water bodies.
In the United States, BMPs are the main feature of regulations of animal feed lot operations (AFOs) and concentrated animal feed lot operations (CAFOs). BMPs are most commonly associated with agriculture and other activities that cause non-point sources of pollution.
However, BMPs also may be included in standard NPDES permits for non-agricultural, point source effluents (Gallagher and Miller, 1996). There are many BMPs available for use in aquaculture, so a simple listing of BMPs is not useful. It is customary to group BMPs according to specific operations or objectives.
Two groups of BMPs for aquaculture will be provided for illustration. Erosion of pond watersheds, embankments, bottoms, and discharge canals may be a significant source of suspended soil particles in effluents.
These particles can increase turbidity and cause sedimentation in receiving waters. Some BMPs that may be adopted to prevent erosion are as follows:
- Use proper slopes and compaction to minimize erosion potential on embankments;
- Design discharge structures and canals to prevent erosion by impact of water or scouring by excessive water velocity;
- Provide vegetative cover on embankments and above water slopes of canals to prevent erosion;
- Provide grass cover on watersheds and gravel on farm roads and tops of embankments to prevent erosion;
- Position aerators to prevent erosion of insides of embankments and pond bottoms by aerator-induced water currents;
- Do not leave the drain open in empty ponds to prevent rainfall erosion and discharge of suspended solids;
- Do not allow livestock to walk on pond embankments or to wade in ponds; and
- Do not remove sediment from ponds and place in spoil piles on embankments or surrounding area; Use sediment to repair pond embankments or dispose of it in a responsible manner.
Of course, the above list is not exhaustive, and many other BMPs could be added. A producer would adopt only those BMPs appropriate for the particular site and operation. Pond effluents contain nutrients that may cause eutrophication of receiving water bodies.
Author:
Claude E. Boyd
