A Forest Development plan, spanning five years, needs to be prepared for each unit within a Forest Company's harvesting area. Roads, stream crosssing structures, and sites should be selected, deisgned and constructed to ensure optimum use of roads, minimize costs of deactivation, and accomodate all resource values.
British Columbia has recently become a world leader in establishing forest practices legislation that will protect the working forests for generations. In fact, many other provinces and countries are modelling new forestry legisation after BC's recently introduced Forest Practices Code (the Code).
The values include complex ecosystems, First Nations' and Indian Reservations' culture and history, recreational opportunities, and the purity of local water sources.
A stream is defined as having continuous and defined banks and a crossing is required for all cotinuous and intermittent draingage flow channels, springs, seeps, and moist areas. The aspects of stream crossings examined in this Web site iinclude planning, design, construction, revegetation, maintenance, and deactivation. They are not intended to be definitive, nor should they be interpreted as the only acceptable options. The material is drawn from Canadian governments, forestry papers, industry expertise, and guidelines, as well as from measures used in good forestry practices. This material may not necessarily reflect US government laws.
While it is recogtnized that there are general environmental techniques and procedures to minimize environmental damage, site-specific conditions may require a solution unique to that location.
All bridge crossings, culverts, fords and ditches must be designed and constructed to maintain natural drainage patters, allow fish passage where need, and avoid cross-surface drainage.
Culverts and Bridge Crossings
Culvert and bridge crossing location and design must match individual site needs and accomodate the following flood returns:
For minor culvert installations, a detailed site plan is usually not required. Major culverts and bridge crossings require a deatiled site plan supported by geortechnical and biophysical information, such as slope and soil composition, stream characteristics, channel configuration, and riparian vegetation.
Construction survey and design requirements
Design of a crossing must conform to current requirements of all agencies and government. During construction, ensure that road and crossing design specifications are followed. Construction specifications and drawings are reviewed and compared against the actual work being completed as well as variations to teh specifications. Often joint licensing/agency on-site visits can clear up questions.
Drawings and specifications
Construction drawings and specifications are applied to all permanent or semi-permanent bridges and major culverts, according to the latest code requirements of the Canadian Standards Association for Design of Highway Bridges, CAN/CSA-S6, and the latest version of the Canadian Foundation Engineering Manual. The peculiarities of unbalanced logging truck loads and eccentricities must be considered in all bride designs.
Factors that impact a crossing
Stream flow diversions
In special situations, the main flow of a stream or river may be temporarily diverted using ditches, berms, dykes, piping, high capacity pumps, or an existing alternate channel, allowing work to proceed in the dry. Diversions are challenging and require the use of planning, permitting, timely execution and forethough. Stream diversions may not be allowed in certain locations or seasons. During all stages of the diversion, it is imperative to avoid siltation by using hay bales, sediment socks, settling ponds, silt fences, filter cloths, and naturally vegetated areas to remove silt from water pumped or running from the work area. Use strainers to keep fish out of pump inlets.
On a non-fish-bearing stream when debris movement is anticipated at the crossing structure, it is necessary to install some form of debris control. "Grizzlies," debris catchers or debris basis can be installed or constructed to catch or divert debris from the culvert entrance. All debris control structures need to be routinely inspected and maintained.
Field layout and marking
Wild animals, environmental degradation, construction, and harvesting practices can damage field markings. Prior to commencing construction, all markings should be reviewed and, if necessary, renewed. Markings for winter use are to be located above the potential snow level.
The right of way should be of variable minimum width needed for road and crossing construction. All standing trees within the clearing width must be felled, and trees must be directionally felled away from streams or wetlands, to the fullest extent possible. Felling and yarding techniques must be selected to prevent streambank destabilization.
|Stream Crossings Directory|
|Protecting Aquatic Habitat||Deactivation|
|Information for this wall chart was compiled
by Eric L. Kay, of Kay and Associates, Forest Road
Consultants and International Training Consultants
This wall chart was produced by Logging and Sawmilling Journal