Water management: global differences and similarities in guidelines for forest road design and potentials for climate change adaptation

Abstract

Forests roads follow standardized design protocols which utilize unpaved gravel to ensure rapid water drainage but also leaves them prone to erosion. However, in many places, precipitation patterns are significantly affected by global climate change. The design of forest roads should be adapted to these changing conditions, which requires a fundamental understanding of current design standards. This systematic literature review was intended to examine the state of the practice by analyzing 32 guidelines from 26 regions worldwide for 46 design features (parameters) significant for drainage and water management. The review was conducted in three phases: identifying relevant design features and categorizing them into six groups (alignment, cross-sectional profile, side slopes, ditches, ditch relief structures, and water crossings), examining their regional specifics and similarities, and discussing climate change adaptation potentials. Several parameters were found to be uniform and in agreement across the analyzed guidelines e.g., the use of a crowned cross-sectional profile and “V”-shaped ditches, the dimension and orientation of cross-culverts. In contrast, some design guidelines included additional or conflicting parameters, such as the discharge of surface runoff water from ditches into streams or riparian buffer zones, and the use of “U”-shaped ditches. Future studies should prioritize the identified key parameters, such as the spacing of ditch relief structures, the choice of ditch type, riparian buffer widths, and dimensions of stream crossings, to develop designs that are well proven and easily adaptable under changing climates. The results of this review can provide a foundation for improving road design practices to mitigate the impacts of climate change.