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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #301679
Title: An online planning tool for designing terrace layouts

Author
item BAY, MELISSA - University Of Missouri
item THOMPSON, ALLEN - University Of Missouri
item Sudduth, Kenneth - Ken
item GANTZER, CLARK - University Of Missouri

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/26/2014
Publication Date: 12/1/2014
Citation: Bay, M.K., Thompson, A.L., Sudduth, K.A., Gantzer, C.J. 2014. An online planning tool for designing terrace layouts. Applied Engineering in Agriculture. 30(6):905-914.

Interpretive Summary: A web-based conservation planning tool for terrace layouts was developed to aid in conserving soil and water resources in an agriculture setting. Terracing is a common conservation practice used to decrease soil erosion by water. Terraces are broad channels constructed across the slope of a field, which reduce the field slope length and allow sediment to settle from runoff. Deciding terrace placement is a complicated and time consuming process, taking up to 50% of the total terrace design time. Therefore, an online tool was developed to aid USDA Natural Resources Conservation Service (NRCS) staff, land developers, and land owners with properly locating terraces in a field. The terrace layout tool provided an interactive web interface for a previously developed program and modified that program to accommodate a wider range of field conditions. Additionally, features were added to assist the user with selecting a best design layout. When compared to manual terrace layouts by NRCS staff, the web-based terrace layout tool provided similar results for terrace placement as well as for overall terrace construction cost. The program allows NRCS staff, land developers, and land owners to design an optimal terrace layout more rapidly and efficiently than conventional methods, and makes evaluating alternative designs much easier.

Technical Abstract: A web-based conservation planning tool, WebTERLOC (web-based Terrace Location Program), was developed to provide multiple terrace layout options using digital elevation model (DEM) and geographic information systems (GIS). Development of a terrace system is complicated by the time-intensive manual layout process, which can take up to 50% of the total design time. The use of WebTERLOC enables automation of the terrace layout procedure, potentially saving time and money. The objective was to develop a web-based conservation planning tool for designing terrace layouts. Functionality of the program was enhanced by integration with an online ArcGIS interface. Multiple help menus and automated drawing and uploading tools increased input efficiency and ease of program use. Based on an earlier version of TERLOC, existing design procedures were modified to enhance layout results for fields with irregular boundaries, topography, and orientation. Program design modifications included variable terrace spacing, channel grade adjustments to meet non-erosive velocities, and the option for multiple key terraces. These new features provide means of selecting layout designs based on conservation, overall terrace length, and farm-ability. Analysis of WebTERLOC and its output was performed by comparing the program layout results to five fields with manually located terraces. Program results were similar to the manual terrace layout results, with fields having large drainage areas most similar. Terrace number, shape, and length were the features with the most similarities. Terrace spacing was found to be most variable, with the program spacing typically larger than the manual result, particularly for fields with flatter slopes. In general, the WebTERLOC program successfully demonstrated its use as an efficient terrace layout planning tool.