Determination and dimension of forest road drainage constructions by georaphic information system (GIS)

Talbot Formula was used to dimension and determine the drainage construction necessities correctly by using Geographical Information Systems (GIS) in shorter time with less labour in Sarıçiçek Forest District, Vezirköprü Forest Enterprises Directorate in this study.97 basket handled pipes or hamps, 3 circular cross-section pipes and 48 box culverts were determined as a result of studies on 148 watersheds of the study area. As a result of available drainage constructions comparasion with drainage constructions calculated by Talbot Formula; with basket handled pipes were constructed instead of bridge in 3 watersheds, 27 basket handled pipes instead of box culverts, 4 box culverts instead of basket handled pipes, 7 pipes instead of box culverts and 28 basket handled pipes were constructed instead of pipes. In addition to the present hydraulic drainage constructions, 11 circular cross-section pipes, 23 box culverts and 13 basket handled pipes, totally 47 drainage constructions should be constructed in the study area.Key Words: Forest Roads, Drainage Construction, GIS, Talbot Formula