Identifying the spatial pattern and importance of hydro‐geomorphic drainage impairments on unpaved roads in the northeastern USA

Abstract

Roads have been widely studied as sources of runoff and sediment and identified as pollutant production sources to receiving waters. Despite the wealth of research on logging roads in forested, upland settings, little work has been conducted to examine the role of extensive networks of rural, low‐volume, unpaved roads on water quality degradation at the catchment scale. We studied a network of municipal unpaved roads in the northeastern US to identify the type and spatial extent of ‘hydro‐geomorphic impairments’ to water quality. We mapped erosional and depositional features on roads to develop an estimate of pollutant production. We also mapped the type and location of design interventions or best management practices (BMPs) used to improve road drainage and mitigate water quality impairment. We used statistical analyses to identify key controls on the frequency and magnitude of erosional features on the road network, and GIS to scale up from the survey results to the catchment scale to identify the likely importance of unpaved roads as a pollutant source in this setting. An average of 21 hydro‐geomorphic impairments were mapped per kilometer of road, averaging 0.3 m3 in volume. Road gradient and slope position were key controls on the occurrence of these features. The presence of BMPs effectively reduced erosion frequency. Scaled up to the watershed and using a conservative estimate of road–stream connectivity, our results for the Winooski River watershed in the northeastern US suggest that roughly 16% and 6% of the average annual sediment and phosphorus flux, respectively, of the Winooski River may be derived from unpaved roads. Our study identifies an under‐appreciated source of water quality degradation in rural watersheds, provides insights into identifying ‘hot spots’ of pollutant production associated with these networks, and points to effectiveness of design interventions in mitigating these adverse impacts on water quality. Copyright © 2017 John Wiley & Sons, Ltd.

Reconstruction and characterization of the surface drainage system functioning during extreme rainfall: the analysis with use of the ALS-LIDAR data—the case study in two small flysch catchments (Outer Carpathian, Poland)

“…Changes in the SDS resulted from incorporation of small in size natural and man-origin incisions may contribute to erosion and fragmentation of the hillslopes (e.g., Luce and Wemple 2001;Kroczak et al 2015-review;Galia at al. 2017), delivery of the sediment material and its transportation to the river channel (e.g., Dietrich et al 1987;Batalla et al 1995;Froehlich and Słupik 1986;Froehlich and Walling 1997;Motha et al 2004;Croke et al 2005;Roy and Sahu 2017;Wemple et al 2017). Erosional transformations of the hillslopes were observed in both catchments (Fig.…”

“…In such areas, creation of hydrologically correct DEM with use of the LIDAR data and creation of the SDS is a relatively easy procedure. It is worth to mention that most of these areas are usually forested and the road network density range from 1 to 2 km·km − 2 (e.g., Wemple et al 2001Wemple et al , 2017Croke et al 2005;Takken et al 2008;Lidberg et al 2017). Moreover, the roads were built mainly to extract timber and projected for use by heavy vehicles (Luce and Wemple 2001).…”

“…This important geomorphological role of the man-origin incisions is also reported in other catchments located in mountain regions. For example, in the Winooski River catchment (USA), 53% of the road network is hydrologically integrated with streams and the unpaved roads contribute to 31% of the annual suspended sediment load (Wemple et al 2017). When the man-origin sub-system is less developed the influence on sediment delivery may be less noticeable.…”

A New Machine‐Learning Approach for Classifying Hysteresis in Suspended‐Sediment Discharge Relationships Using High‐Frequency Monitoring Data

“…The Mad River watershed, located in the Green Mountains of Vermont within the Lake Champlain Basin (Figure ), was selected as a study site based on available long‐term stream gauge records and ongoing geomorphic and sediment dynamics studies (Stryker et al, ; Wemple et al, ). Elevation ranges from 132 m to 1,245 m above sea level, with forests (83% of watershed area) dominating all but the valley floors, which are occupied by agriculture (8%) and village centers and other developed lands (8%) (Table ).…”

Conservação De Estradas Não Pavimentadas Por Meio De Modelo Geolocalizado

“…A conectividade hidrológica relacionada às estradas tem recebido considerável atenção nos últimos anos por meio de estudos de campo, Sensoriamento Remoto e/ou baseados em Sistema de Informação Geográfica (SIG) (WEMPLE et al, 2017). Nesse contexto, o SIG é uma importante ferramenta de análise e tomada de decisões no planejamento da rede viária e na acessibilidade em ambiente rural (SAKAMOTO; LIMA, 2016).…”