RECOMMENDATIONS FOR CONSTRUCTING FOREST STREAM CROSSINGS TO CONTROL SOIL LOSSES

ABSTRACT: Stream water samples were collected once daily and throughout storms from a small forested watershed in north central West Virginia for approximately 8 years. The turbidities of the samples were measured to determine how water quality changed in response to the construction of three associated stream crossings. The influence of the crossings and the immediate approaches to the crossings could be isolated in this study because sediment inputs from the hillsides of the watershed were restricted by silt fence that was installed along the entire stream perimeter, except in those crossings and approaches to the crossings. Turbidity results prior to, during, and following crossing construction provided valuable information on the short- and longer-term effects that stream crossings can have on water quality. Based on the results of this study, recommendations to reduce soil losses from future crossing construction efforts in steep terrain were developed. These recommendations include: employing full-bench construction, especially where road approaches are at small angles to the stream; requiring the immediate installation of permanent culverts rather than allowing the initial installation of temporary culverts; requiring that in-stream equipment operation pads, if needed, be constructed of large, clean, nonfriable stone; and altering contract language so that soil covering is required within a specified limited number of days after disturbance is started, rather than within a set amount of time after the disturbance in the area is completed. KEY TERMS: culverts; fillslopes; full-bench construction; stormflow; stream turbidity