1a.Objectives (from AD-416):
Assemble spatial databases to facilitate development of watershed-scale conservation planning tools.
1b.Approach (from AD-416):
Tasks will include: Assembly of county-based field map boundary files into a regional (Iowa and southern Minnesota) database with Hydrologic Unit Code addressing. Incorporate access to LiDAR topographic, soils, and crop data layer into database. Identify options for modeling of hydrologic flows at the HUC-12 watershed scale through processing, rescaling, and terrain analysis of LiDAR data. The products will provide a basis to develop watershed scale conservation planning tools that translate between field and watershed scales.
Improving the quality of waters discharged from agricultural watersheds will require comprehensive and adaptive approaches for planning and implementing conservation practices. A major challenge to traditional watershed scale conservation planning is the capacity to translate planning from watershed to farm and field scales. This translation of scale is required because while conservation practices can be planned based on a watershed scale framework, they must be implemented by individual landowners in specific fields and riparian sites that are under private ownership.
Significant progress has been made in the incorporation of light detection and rating (LiDAR) elevation data, soils data, and a crop data layer into a database framework from which a suite of best management practice scenarios will be developed and applied to each Hydrologic Unit Code watershed over a several-state region. Test watersheds have been selected upon which to develop the framework for data organization, data processing, and eventual dissemination of best management practice (BMP) recommendations. Field boundaries have been updated across a three-state area, which will provide the spatial framework for conservation planning. Field specific land use information has been generated over a five-year period using National Agricultural Statistics Service Crop Data Layers, including information on rotation practices and other land use practices which may lead to increased nutrient delivery. Methods for siting optimal locations for several BMP’s (including nutrient reduction wetlands, grassed waterways, and controlled drainage) are well developed and supported by published literature, and planning is underway for further refinement of chosen parameters through test watershed site visits. Alternative LiDAR processing scenarios, including varying scales, preprocessing steps, and terrain analysis data generation, have been examined to identify optimal methods for modeling hydrologic flow. Progress is monitored through regular telephone calls between ARS and EDF and occasional meetings. Discussion between ARS and EDF representatives will continue regarding the theoretical and practical nature concerning how, and to whom, this information will be disseminated via a web-based interface.