Using ArcGIS hydrologic modeling and LiDAR digital elevation data to evaluate surface runoff interception performance of riparian vegetative filter strip buffers in central Iowa

Abstract

The Midwest is well known for agriculture, and Iowa is a leader in corn (Zea mays L.) and soybean (Glycine max [L.] Merr.) production. Fertilizers and chemical pesticides used to increase crop production can adversely affect the soil and water health. Midwest farmers also produce livestock and graze cattle on pastureland that can lead to excessive surface runoff and soil erosion. Establishing vegetative filter strips (VFSs) along the edge of farmland is one of the best management practices (BMPs) to reduce nutrient and sediment loss. However, studies have revealed that the classic VFS design along the length of an agricultural field does not adequately address nonuniform flow through the buffer. New designs are being researched to increase the efficiency of the VFS. In order to accurately implement new design strategies, the runoff flowpaths into the VFS need to be accurately modeled. This research assesses the performance of existing established VFS buffers of selected sites by modeling and analyzing the flow accumulation from the field into the VFS using geographic information system (GIS) and light detection and ranging (LiDAR) derived digital elevation model (DEM) 5 × 5 m data. This study also employed the new coefficient of flow interception (CFI) approach that improves the process of identifying areas where flow is concentrated and designing more efficient filter strips to account for concentrated runoff. In this study, the performance of VFS in three sites was evaluated by developing and using the CFI. Among the three sites, site 1 had very poor efficiency and no flow passes through the VFS, site 2 had low efficiency, and site 3 had excellent efficiency.

Assessing Surface Flowpath Interception by Vegetative Buffers Using ArcGIS Hydrologic Modeling and Geospatial Analysis for Rock Creek Watershed in Central Iowa

“…The initial and final phases of this study were conducted during -2006(Bansal, 2006 and 2013-2015 (Shrivastav, 2015), respectively. These field and laboratory efforts used detailed on-site observations, GPS-assisted ground-truthing methods, and GIS-based hydrologic data, DEM data, geospatial map comparison analysis, and high-resolution aerial imagery for three agricultural field research sites in Rock Creek watershed ( fig.…”

“…During the initial research phase (Bansal, 2006), these GIS software programs included ArcGIS 9.3, ArcView (AV) 3.3, AV Soil and Water Assessment Tool (AVSWAT), and AV Spatial Analyst extensions (ESRI, 2005). ArcGIS 10.3 and 10.4 (ESRI, 2014, 2016) were used during the final phase (Shrivastav, 2015). The topographic surfaces of the three research sites were represented by regularly gridded DEM datasets.…”

“…On-site observations and GPS ground-truthing surveys for sites 1, 2, and 3 were initially conducted in 2005 using a Trimble 5800-R8 (Trimble, 2005) handheld GPS unit (Bansal, 2006). The final phase of on-site observations and ground-truthing surveys was conducted in 2013 and 2014 using Magellan SporTrak Map and Explorist 200 (Magellan, 2004) handheld GPS units (Shrivastav, 2015). Because these GPS units are consumer-grade and are considered less accurate than survey-grade GPS units, both of the Magellan GPS units were used simultaneously during the final phase for cross-checking position coordinates.…”

“…Hydrologic modeling and geospatial map comparison analysis using ArcGIS software and high-resolution light detection and ranging (LiDAR) digital elevation model (DEM) data have been shown to generate accurate surface flowpath networks and drainage areas (NSSDA, 1998;Murphy et al, 2008;Zhao et al, 2010;Vaze et al, 2010;Shrivastav, 2015). Moreover, several studies have further applied and evaluated LiDAR DEM data for improving the results from modeling low-relief and depression topography, determining the effects of various DEM sources on hydrologic applications, and rectifying errors associated with DEM interpolation (Jones et al, 2008;Liu, 2008;Zhang and Huang, 2009;Bater and Coops, 2009;Li and Wong, 2010;Li et al, 2011).…”

“…The overall objective of this study was to quantify the accuracy of simulated surface flowpaths relative to observed and ground-truthed BMP drainage features for three selected Rock Creek watershed research sites to improve the placement of VFS and other vegetative buffer practices for intercepting surface runoff. This study used the internet-available USGS 7.5 min quadrangle map-derived 30 m × 30 m National Elevation Database (NED) DEM (typically used for designing and siting VFS buffers) and the airborne sensorderived LiDAR 1 m × 1 m DEM (Wehr and Lohr, 1999;Shrivastav, 2015). To process and analyze these DEM datasets, GIS hydrologic modeling functions and geospatial map comparison analysis procedures were used.…”