A Geospatial Methodology to Identify Locations of Concentrated Runoff from Agricultural Fields

Abstract

A geospatial methodology has been developed that utilizes high resolution lidar-derived DEMs to help track runoff from agricultural fields and identify areas of potential concentrated flow through vegetated riparian areas in the Coastal Plain of Virginia. Points of concentrated flow are identified across 74 agricultural fields within the Virginia portion of the Chesapeake Bay watershed. On average, 70% of the surface area of the agricultural fields analyzed drains through less than 20 m of the field margin, and on average 81% of the field surface area drains through 1% or less of the field margin. Within the riparian buffer, locations that were predicted by the geospatial model to have high levels of concentrated flow were found to exhibit evidence of channelization. Results indicate that flow concentration and channelized flow through vegetated riparian areas may be common along the margin of agricultural fields, resulting in vegetated riparian areas that are less effective at sediment trapping than assumed. Additional results suggest that the regulations governing the location and width of vegetated riparian may not be sufficient to achieve goals for reducing sediment and nutrient runoff from nonpoint agricultural sources. Combined with the increasing availability of lidar-derived DEMs, the geospatial model presented has the potential to advance management practices aimed at reducing nonpoint source pollution leaving agricultural fields.(KEY TERMS: agricultural runoff; GIS; lidar; Chesapeake Bay; riparian buffers.)

A comparative review of the state and advancement of Site-Specific Crop Management in the UK and China

“…Airborne LiDAR has been shown to successfully estimate maize height and biomass at the tasseling stage in Gansu Province, China [61] , while in the UK, it has been used to monitor the agri-environment [62,63] . Detailed digital elevation models derived from airborne LiDAR can also allow the modeling of water flow, accumulation and runoff from fields [64] .…”

Using Random Forest Classification and Nationally Available Geospatial Data to Screen for Wetlands over Large Geographic Regions

“…The Chesapeake Bay Agreement recognizes a 15 m (50 ft) wide vegetative buffer extending from theoretical centerlines as forested riparian areas, enforced in lands within the Coastal Plains portion of the Chesapeake Bay watershed [46]. Thus, a 15 m buffer width extending from each side of NHD streams and waterbodies was used to represent the riparian zone, similar to the practice used by Hancock et al [47]. The resulting polygon vector dataset was rasterized with the 3 m pixel resolution constraint and assigned values corresponding to either within or outside of the riparian zone ( Figure 4E).…”

Identifying Surface Runoff Pathways for Cost-Effective Mitigation of Pollutant Inputs to Drinking Water Reservoir

“…The research conducted in the subject matter discussed in this paper can be divided into four groups: The effectiveness of riparian buffer zones [5,32,34,49], the determination of critical source areas and hydrologically sensitive areas [6,7,10,17,[50][51][52], modelling of non-point source pollution [16,53] and sustainable stormwater management [27,53]. In order to develop a method of identifying surface runoff pathways, we tried to use the advantages of mitigation efforts and to eliminate the existing gaps and disadvantages in the approaches applied so far.…”

“…The effectiveness of riparian buffers is most often studied using field methods [5,32,34] and the authors increasingly notice the problem of concentrated flow through riparian buffers [5,34,49]. Compared to these studies, our approach gives an opportunity to quickly diagnose the state of vegetation strips, it may also be a preliminary phase of research, indicating the locations of cost-effective net monitoring.…”