Interactions and Relationships of Road Born Sediment and Total Sediment Production in a Small Agricultural Catchment

A Graduate Defense Seminar by Benjamin Afton Silliman, MS Student in Forest Science, who will present Interactions and Relationships of Road Born Sediment and Total Sediment Production in a Small Agricultural Catchment in 460 Kottman Hall linked to 117A Williams Hall.

Unbound gravel roads are thought to be one of the largest anthropogenic sources of fine sediments reaching stream channels in small watersheds. This sediment deposition can reduce water quality in streams negatively impacting aquatic habitat as well as being a detriment to municipal drinking water sources. With rural land use practices changing due to the expansion of natural gas exploration in the United States along with the continued use of these resource roads for timber extraction along with recreational use, the relationship between rural gravel road networks and surface water quality needs to be addressed. This study sought to identify the driving forces of road born sediment by quantifying road surface sediment production using controlled rain events, and to relate this production to measured, catchment scale sediment production during a natural rain event. Eight controlled rain events were simulated on a rural road network in a small 212 hectare catchment in eastern Ohio resulting in road surface sediment production rates that ranged from 18 to 64 g/m2 with an average of 42 g/m2. The study showed that although the road network represents less than 1% of the total land cover (3125 m of road, averaging 4 meters wide) it has the potential to contribute between 31% and 47% of the total sediment at the mouth of the watershed. This study highlights the need to disconnect rural road networks from stream channels in order to prevent negative water quality impacts associated with sedimentation.