ALABAMA S BEST MANAGEMENT PRACTICES Protection of Water Quality During Timber Harvesting
Water Quality Responsibility Landowners and/or involved professional forestry practitioners such as: Forest resource managers, Timber purchasers, Loggers, Vendors or contractors, Forest engineers, and Others
Silvicultural Non Point Source Pollutants Sediment Organic materials Temperature Trash Pesticides Nutrients (Fertilizers)
Harvesting and Site Prep Effects Increases water yield Sediment export 4.1 t/ac/yr first year after harvest Nutrient loss, Phosphate eutrophication Nitrate health hazard Both below harmful standards Fertilization may lead to high nutrient loads
Virginia BMP Watershed: Sediment
Virginia BMP Watershed: Nitrogen Loss
Watershed yield 20 ac, 5 years
Timber Harvesting BMPs Timber harvest planning Streamside management zones Wetlands Stream crossings Road planning and construction Harvest area
Timber Harvest Planning Tactical planning When to harvest particular tracts When to build roads and landings Operational planning Road, trail, and landing location Stream crossings Slopes Soils Road and crossing construction Drainage Surfacing Selection and size
Water Quality Protection by SMZs Temperature Organic matter Nutrients Sediment
Riparian Area Important to system health/function Provides shade Provides organic matter input Delays water release Traps sediment Ties up nutrients
SMZ Perennial Streams Tree cover at least 50% canopy, 35 feet from the bank, for wildlife 50 feet Shading Leaf and twig input for food and habitat Tree falls for habitat Bank trees for channel stability Avoid disturbance >= 35 ft from stream bank Comply with stream crossing BMPs
SMZ Perennial Streams Tree cover Avoid disturbance >= 35 ft from stream bank Leaf and plant cover minimize erosion within the SMZ Leaf and plant cover slow upland runoff and drop out sediment Undisturbed soil maximizes infiltration of runoff and rainfall Plant growth removes nutrients from runoff Comply with stream crossing BMPs
SMZ Intermittent Streams Avoid disturbance >= 35 ft from stream bank Maintain leaf litter and ground cover Comply with stream crossing BMPs
SMZ Ephemeral channel No specific requirements Avoid disturbance near streams and to stream banks
SMZ - Wildlife Habitat Wider SMZ (50 ft) for use as corridors or habitat Mast (hard mast) producing species retained Recognition of timber type boundaries outside of SMZ Riparian areas
Wetlands USACE Federal Manual for Delineating Jurisdictional Wetlands http://www.wetlands.com/pdf/89manv3b.pdf May include: Coves and lower slopes, Branch bottoms, Creek bottoms, River bottoms, Muck swamps, Peat swamps and cypress/gum ponds, and wet fiats Alteration of land use in wetland requires 404 permit Silviculture operations exempt from 404 if BMPs are followed Intention is to maintain land use Good idea to have mgmt plan to support exempt status Fifteen federal Mandatory BMPs (Page 19)
Federal Wetland BMPS 1. Roads and trails should be the minimum feasible number, width, and total length 2. Roads and trails should be located sufficiently far from streams or other water bodies (except for crossings) ; 3. Road fill shall be bridged, culverted or otherwise designed to prevent the restriction of expected flood flows; 4. Road fill shall be properly stabilized and maintained during and following construction to prevent erosion
Federal BMPS 5. Minimize machine traffic outside the fill area; 6. Minimize disturbance of vegetation in designing, constructing and maintaining roads; 7. Design, construction and maintenance of the road crossing shall not disrupt movement of aquatic species 8. Borrow material shall be taken from upland sources whenever feasible
Federal BMPS 9. The discharge shall not take, or jeopardize the continued existence of a threatened or endangered species as defined under the Endangered Species Act, or adversely modify or destroy the critical habitat of such species; 10. Discharges into breeding and nesting areas for water fowl, spawning and wetlands shall be avoided if less harmful alternatives exist;
Federal BMPS 11. No fill in the proximity of a public water supply intake; 12. No fill in areas of concentrated shellfish production; 13. No fill in a component of the National Wild and Scenic River System; 14. Fill must be free from toxic pollutants in toxic amounts; and 15. All temporary fills shall be removed in their entirety and the area restored to its original elevation.
Wetland BMPs Perennial SMZs Perimeter of major drainage Along any open water (oxbow, sloughs) Restore any minor alterations in drainage to preharvest conditions Road construction should not affect hydrology Cross drainage Fill
Stream Crossing Impact Link upland sources of sediment to streams Sediment from crossing construction and use Sediment from poor construction and failure Barriers to fish passage
Stream Crossing BMPs Minimize number of crossings Expensive and major source of sediment Layout and type Crossing location Approach design Choice of crossing Maintenance and removal
Crossing Location Minimize length of road in floodplain Minimize slope into crossing Avoid locations with wide channels, multiple channels, or wide floodplains Cross perpendicular to stream flow
Road Approach Design Straight road (50 ft) into the crossing A curve into the crossing Increases the disturbance in the flood plain Increases the crossing width (longer culverts, wider bridges) Angled/curved roads may lead to bank erosion following flooding Increases disturbance in the SMZ
Road Approach Design Road surface drainage Slope road surface Construct broadbased dips Surface road with rock and grass especially highly erodible steep slope Direct runoff into SMZ Not into ditch that dumps into stream Minimize slope into crossing
Choice of Crossing Fords Natural and constructed Culverts Bridges Temporary and permanent
Fords Low bank height Hard bottom Constructed Hardbottom made with geotextile, rock, and geoweb Challenges Sediment from construction and use Least suitable for all season roads Avoid damming or adding fill to stream
Ford Design
Culverts Proper installation techniques Culvert size Based on acreage and landform for 20? year event Accommodate high flow in approach Low spot in approach should be just above culvert top and away from the main channel
Culverts Long term issues Removal Maintenance Sediment from construction and use less than ford Culvert failure is a major source of sediment
Streams: Culvert Sizing Recommended Culvert Diameter (Table II, Page 7) Drain area (ac) L. Coastal Plain U. Coastal Plain Piedmont Mountains 10 12 12 12 18 50 30 18 30 36 100 48 30 42 48 200 60 42 54 2 x 48
Culvert Installation Length of culvert (ft) Width of road + Width of fill slope * 2 + 2 Short culverts Buried by fill slopes
Culvert Length Road Surface 15 ft 18 fill 36 pipe =4.5 ft +1ft 1:1 Fill slope +1ft 4.5 ft 15 ft 4.5 ft 1 + 4.5 + 15 + 4.5 + 1 =26 ft
Multiple culverts 36 inch pipe with 18 inch fill 2*24 inch pipes with 12 inch fill
Culvert Failure Culvert too small Culvert too short Culvert installed poorly Incorrect slope of culvert Culvert poorly tamped in Outlet or inlet above channel Too little fill overtop Inlet unprotected Poor location
Culvert Failure High water design/relief Culvert damage Crushed ends Debris dams Sedimentation of inlet and culvert
Bridges For truck roads Highly engineered Well designed approaches and sills For skid trails Standard bridge sections of metal or wood Relatively short span Least sediment since little or no in-stream activity Most expensive for permanent crossings, low cost per use for temporary crossings
Skidder Bridge with Slash Mat
Crossings with Fill Logs, slash, rock or soil crossings are undesirable Difficult to restore channel Federal BMPS If it restricts flow it violates 3 If it is on a perennial stream it violates 7 If it is not removed following activity it violates 15
Road Construction and Planning Minimize road grade Avoid SMZs other than crossings Avoid highly erodible soils Avoid dredge and fill in wetlands or in locations that may reach the waters of the state Avoid old roads, ditches and gullies that are highly eroded
Road Construction Design to likely traffic levels Log right-of-way before clearing and grubbing Don t bury stumps or logs Minimize cut and fill slopes Install road drainage and water diversion
Road Drainage Slope of road surface 2-4% to prevent water traveling down the road surface Crowned Outslope Inslope Turnout (wing) ditches moves water from road edge or ditch to undisturbed soil Distance between turnouts dependent on road slope
Intervals Between Structures % Slope Distance between water bars Distance between Broad-based dips, turnouts 3 200 235 5 135 180 10 80 140 15 60 125 20 45 30 35 40 30 TABLE 3, PAGE 12
Road Drainage Culverts move water from channels or ditches under road Avoid excess volume in the ditch ditch erosion Avoid water running over road Distance between culverts based on road slope Broad-based dips on inslope or outslope roads divert runoff into turn out or wing ditch
Road Drainage: Broad-based Dips Effective way to divert water from permanent road that does not interfere with truck of skidder traffic Outslope of 3% Depth of 9-15 inches Fill with crushed rock
Broad Based Dips
Road Maintenance Protect culvert or wing ditch outfall from erosion with rock or organic debris, especially on steep terrain Control traffic Ruts on road counteract slope (crown, inslope, outslope) channel water down the road, and wear down BBD s Establish vegetation on less travelled roads Rock surface main roads and steep slopes Mulch fill and cut slopes where vegetation won t be quickly established
Harvest Area Locate landings and trails outside of SMZs and drainage pattern Landings Uphill, gently sloping Skid trails avoid steep slopes have breaks in slope when steep slopes are necessary Felling Do not leave trees, tops, or slash in streams Maintain recommended tree cover in SMZs Retirement
Harvest Area Retirement Trails and temporary roads Establish water bars at recommended distances Restore natural drainage Remove ruts especially on steep terrain, low areas Remove debris and fill from streams and channels Revegetation seed, fertilize, lime highly erodible areas Landings
Types of Water Bars Shallow Constructed prior to and during logging, temporary structure Deep Use of road or trail is finished, permanent structure
Water Bar and BBD Failure Berm erodes Berm is fill material and gets waterlogged Too much runoff Not high enough Traffic over the berm (when wet) Depression fills with sediment Angle too shallow No outlet Slope Outlet erodes Angle too steep Road or roadside too steep Outlet in to ditch or stream
Intervals Between Structures Depends on Road Gradient % Slope Distance between water bars Distance between Broad-based dips, turnouts 3 200 235 5 135 180 10 80 140 15 60 125 20 45 30 35 40 30 TABLE 3, PAGE 12
Harvest Area Retirement Trails and temporary roads Landings Address debris piles (knock down, redistribute, burn) Smooth, restore drainage Revegetate Trash disposal
Revegetation Follow recommendations in Erosion Control & Wildlife Planting for Forestry Operations Get local advice for best, low cost high success cover planting
Inspected Site Features About 75% of inspected sites need some type of SMZ (perennial or intermittent streams) Around 50% have or could have a stream crossing 10 to 30% of harvests have wetlands Most of the sites are rated on 20 to 30 conditions (37 total) On average those have 2-3 deviations from full compliance Timber harvesting is rated on nearly all inspections Having a contract is more important than professional advice in increasing compliance
SMZ Compliance
Stream Crossing Compliance
Forest Roads Compliance
Timber Harvesting Compliance
Wetland Compliance
Score For Adequate BMPs