BMP Management Measures
Silvicultural nonpoint source pollution impacts depend on site characteristics, climatic conditions, and the forest practice employed. Sediment, nutrients, pesticides, and temperature are pollutants commonly associated with forestry activities.
The objective of this management measure is to ensure that silvicultural activities, including timber harvesting, site preparation, and associated road construction, are conducted in a way that takes into account potential nonpoint source pollutant delivery to surface waters. Pre-harvest planning has been demonstrated to play an important role in the control of nonpoint source pollution and efficient forest management operations. Components of this measure address key aspects of forestry operations relevant to water quality protection, including the timing, location, and design of harvesting and road construction, the identification of sensitive areas or high-erosion-hazard areas; and the potential for additional cumulative contributions to existing water quality impairments.
Streamside Management Areas (SMAs)
This management measure establishes areas along surface waters that are managed to protect the water quality of the adjacent water body. Streamside Management Areas (SMAs) protect against soil disturbance and reduce the delivery to water bodies of sediment and nutrients from upslope activities. Canopy species in SMAs shade water bodies, which moderates water temperature, and provide the detritus that often serves as an energy source for stream ecosystems. Trees in the SMA also provide a source of large, woody debris to water bodies.
Road Construction / Reconstruction
Road construction is often the largest source of silviculture-produced sediment. The purpose of this management measure is to reduce the generation and delivery of sediment from road construction or reconstruction. This is to be accomplished by following the preharvest plan layouts and designs for the road system, incorporating adequate drainage structures, and properly installing stream crossings. Other components of this measure include avoiding constructing roads in SMAs, removing debris from streams, and stabilizing areas of disturbed soil such as road fills.
The objective of this management measure is to manage existing roads to prevent sedimentation and pollution from runoff-transported materials. This management measure describes how to manage existing roads to minimize erosion, maintain stability, and reduce the risk of failure or decreased effectiveness of drainage structures and stream crossings. Components of this measure include the use of inspections and maintenance actions to prevent erosion of road surfaces and ensure the continued effectiveness of stream crossing structures. The measure also addresses appropriate actions for closing roads that are no longer in use.
This management measure is intended to reduce NPS pollution resulting from timber harvesting operations. The measure includes components for the location of landings, for the operation of ground skidding and cable yarding equipment, and for the prevention of pollution from petroleum products. Harvesting practices that protect water quality and soil productivity can also reduce total mileage of roads and skid trails, lower equipment maintenance costs, and provide better road protection and reduce road maintenance. Appropriate skid trail location and drainage and proper harvesting in SMAs are addressed by this measure. Erosion from the siting and operation of timber harvest operations can be reduced by conducting preharvest-planning.
Site Preparation and Forest Regeneration
In some areas mechanical site preparation is of great concern for potential impacts to water quality. This is especially true in areas that have steep slopes on highly erodible soils, or where the site is located in close proximity to a water body. Careful regeneration of harvested forestlands is important in providing water quality protection from disturbed soils. This management measure is intended to reduce the impacts of mechanical site preparation and regeneration operations and to confine on-site potential nonpoint source pollution. Components of this measure address keeping slash materials out of drainages, operating machinery on the contour and protecting the ground cover in ephemeral drainages and SMAs.
Prescribed burning is aimed at reducing slash and competition for nutrients among seedlings and protecting against wildfire. Prescribed fires that burn intensely on steep slopes in close proximity to streams and that remove most of the forest floor and litter down to the mineral soil, are most likely to adversely affect water quality. The purpose of this management measure is to reduce the potential nonpoint source pollution and erosion resulting from prescribed fire for site preparation and from methods for suppression of wildfire. Prescribed fires should be conducted under conditions to avoid the loss of litter and incorporated soil organic matter. Bladed firelines should be stabilized to prevent erosion, or practices such as handlines, firebreaks, or hose lays should be used where possible.
Revegetation of Disturbed Areas
Revegetation of areas of disturbed soil can successfully prevent sediment and pollutants associated with the sediment (such as nutrients) from entering nearby streams. The objective of this management measure is to reduce erosion and sedimentation by the rapid revegetation of areas of soil disturbance from harvesting and road construction. The disturbed areas to be revegetated are those localized areas within harvest units or road systems where mineral soil is exposed or agitated such as road cuts, fill slopes, landing surfaces, cable corridors, or skid trails.
Forest Chemical Management
Chemicals used in forest management are generally pesticides (insecticides, herbicides, and fungicides) and fertilizers. Since pesticides may be toxic, they must be properly mixed, transported, loaded, and applied and their containers must be properly disposed of to prevent potential nonpoint source pollution. Fertilizers must also be properly handled and applied since they also may be toxic or may shift surface water energy dynamics, depending on the exposure and concentration. The objective of this management measure is to ensure that the application of pesticides and fertilizers does not lead to contamination of surface waters. Components of this measure include applications by skilled workers according to label instructions, careful prescription of the type and amount of chemical to be applied, and the use of buffer areas for surface waters to prevent direct application or deposition.
Wetland Forest Management
Forested wetlands provide many beneficial water quality functions and provide habitat for aquatic life. The purpose of this management measure is to protect the aquatic functions of forested wetlands
For additional information, visit: http://www.epa.gov/owow/nps/MMGI/index.html
Courtesy: Alabama Forestry Commission