Conservation Practices Inventory for Select Iowa HUC 12 Watersheds
To track the success of the Iowa Nutrient Reduction Strategy and the impacts of the various conservation implementations, a baseline dataset has to be created to allow for comparison. While individual organizations and programs often keep track of the practices they install or advocate, the State of Iowa has lacked a comprehensive database of practices in each watershed. This project will provide a meaningful record of in-field and off-field conservation practices for reducing erosion and nutrient loss, and data can be used in research and modeling.
This project is creating an accurate baseline inventory of six commonly used agricultural conservation practices used in Iowa — pond dams, WASCOBs (Water and Sediment Control Basin), terraces, grass waterways, contour buffer strips, strip cropping — in specific HUC 12 level watersheds in Iowa in the 2007-2010 timeframe. Data created with this grant funding will be a portion of a larger statewide dataset being funded by several state agencies and private nonprofit organization in a multi-year effort. This project intends to finish all or portions of 10 HUC 8 level watersheds.
Student interns will visually identify and digitize conservation practices on the landscape using aerial imagery, both natural color and infrared, and LiDAR-derived products such as hillshade and slope. By viewing several years of imagery in conjunction with the elevation data, practices can be distinguished and outlined after several hours of training. Completed data will be sent to Iowa Department of Natural Resources personnel for quality assessment, then returned to the GIS Facility for inclusion in a free online, downloadable dataset organized by HUC 12.
Individual organizations and programs often track conservation practices they install or promote. Yet the State of Iowa lacks a comprehensive database of conservation practices in each watershed. This project was part of a larger effort to create an accurate baseline inventory of six common conservation practices — pond dams, WASCOBs (Water and Sediment Control Basin), terraces, grass waterways, contour buffer strips, and strip cropping. Using color imagery and elevation data, information was gathered on these six practices for 98 of Iowa’s 1,700 HUC 12 level watersheds. Once this statewide effort is completed in summer 2018, the data can be used to track changes in conservation practice type, location, quantity and density. The datasets for this project have been quality checked by Iowa DNR staff and are available for free download at www.gis.iastate.edu/gisf/projects/conservation-practices.
During this reporting period, students completed 56 watersheds worth of data. Eight students worked on digitizing six specific conservation practices in the Upper Chariton, Maple and Boyer HUC 8 watersheds. Portions of the English River area in the Lower Iowa also were completed. The students evaluated the presence of terraces, WASCOBs (Water and Sediment Control Basin), pond dams, grassed waterways, contour buffer strips and strip cropping using hillshade, CIR imagery, summer imagery and a high resolution land cover dataset. The inventory is based on the years 2007-2010, which coincides with the years Lidar was collected across Iowa. The total number of watersheds completed from all funding sources was 106. The completed watersheds drafts were sent to the Iowa Department of Natural Resources staff for a final accuracy check.
Student interns are visually identifying and digitizing conservation practices on the landscape using aerial imagery, both natural color and infrared, and LiDAR-derived products such as hillshade and slope. By viewing several years of imagery in conjunction with the elevation data, practices can be distinguished and outlined after several hours of training. During this reporting period, which was mostly five to six hour workdays, students completed 42 watersheds worth of data.