ABSTRACT Mount Diablo State Park exemplifies many other conservation areas where managers balance the dual missions of protecting natural resources while providing public access. Roads and trails that crisscross the park are etched into the geomorphic surface, capturing and redirecting storm runoff, and presenting both a challenge for soil conservation and a consequence of construction and maintenance. We used field mapping, remote sensing, and modeling to assess erosion along the roads and trails in Mount Diablo State Park, which encompasses the headwaters of several urbanized watersheds. The field mapping in 2011 determined that 56% of the assessed roads and trails required either repair or reconstruction to control erosion and that ~67% of the culverts in the park required either repair or replacement. Aerial photography and modeling showed that other erosion (unrelated to roads or trails) preferentially occurred during wet periods, in specific lithologies, and on convergent slopes. Although lithology and climate drive slope-forming geomorphic processes, we found that the road and trail system (1) expanded the stream network with a capillary-like system of rills, (2) catalyzed prolonged erosion, and (3) altered the timing and pattern of sediment yield. In addition to water-driven erosion during wet periods, road and trail surfaces were subject to mechanical and wind erosion during dry periods. Spatially, dry erosion and runoff both conformed with and crossed topographic gradients by following the road and trail network. Road- and trail-induced erosion occurred across a wider range of rock properties and slope geometries than is typical for other erosion. Hence, the roads and trails have expanded the spatial and temporal boundary conditions over which geomorphic processes operate and, due to continual soil disturbance, have accelerated erosion rates. Although road density is a commonly used metric to rank road-related impacts at watershed scales, it misses both spatial variability and the opportunity to identify specific road and trail segments for remediation. We developed a spatially explicit scoring scheme based on actual erosion and the potential for sedimentation of discrete waterbodies. The data were incorporated into the park’s road and trail management plan in 2016.

ABSTRACT The built environment of peninsular Charleston, South Carolina, has been strongly influenced by the ethos of architectural preservation. However, increased frequency of storm and tide-related flooding has been affecting property and public services, and threatens human and environmental health. Management processes for excess water in this urban area must adapt to the challenges resulting from historic development including the fill of tidal creek systems, sea-level rise, and the influence of large storm events on drainage infrastructure. The City of Charleston has adopted several strategies to manage flooding and encourage progressive development. Large-scale drainage improvement projects capitalize on a geologic framework that provides for deep tunnel excavation and drainage system construction. Novel approaches in zoning codes provide some incentives for land owners to use lower impact design techniques in return for more flexible design standards. This field tour will guide participants through this historic city, and will provide a glimpse of the geologic setting, development history, and environmental pressures that have compelled the city’s proactive stormwater management.

Abstract The objective of this field trip is to examine variability in stream systems in west-central Ohio at different time and space scales. Scales of study range from watershed changes over 10 3 –10 4 years as drainage networks are established during glacial retreat, to reach-scale changes in tributary streams in response to human impacts and land use change over 10 1 –10 2 years, to diurnal and event-driven changes in water quality over 10 –2 to 10 –3 years. Drainage network changes in the Little Miami River and Mad River systems occurred through stream capture and were dependent on the location of early meltwater channels relative to ice lobe position and relict bedrock topography. At the reach scale, channel morphology (width, depth, slope, shape, and pattern) is dependent on mean discharge of water and sediment to the reach. Tributary streams to the Little Miami River, Mad River, and Buck Creek illustrate the impact that historic changes in land use, water and sediment discharge, channelization, and straightening of stream reaches have had on channel morphology and vertical stability. At the cross-section scale, flow characteristics, including stream stage and physical water quality parameters (temperature, pH, specific conductivity, oxidation-reduction potential, dissolved oxygen, and turbidity), are being measured on Buck Creek and Beaver Creek. Though some characteristics change diurnally in response to internal stream processes, event-based changes in response to stormflow reflect source area contributions of runoff and sediment.