Minimizing Road Construction plus Forwarding Costs under a Maximum Soil Disturbance Constraint

ABSTRACT: A model is developed to minimize the sum of road construction plus forwarding costs with the constraint that rut depth caused by the forwarder cannot exceed a maximum depth during the anticipated season of operation. Road spacing, forwarder trail spacing, and forwarder capacity are used as decision variables in developing the transportation plan. The total cost was minimized using the optimum road spacing approach. The model identifies whether the cumulative rut depth caused by the forwarder exceeds the maximum allowable rut depth at the point of or prior to the spacing that minimizes the cost, and if so, the rut depth limits the road spacing. If the road spacing at the point of minimum cost is less than the road spacing at the maximum allowable rut depth, road spacing is not constrained by rut depth. This model allows planners to examine the tradeoffs between forwarder parameters, trail spacing, and trail length. The solution procedure of the model is described and a computer program is used to apply this model using a numerical example.