Equipment Research and Useful Modeling Technologies for Watershed Analysis

The equipment and tools for watershed assessment and analysis in the field are numerous and varied, and used by biologists, geomorphologists, engineers, and other related professions.  Common tools are measuring devices, from simple items such as handheld surveying equipment and measuring rods to more modern items like cameras, unmanned aerial drones, and light detection and ranging (LIDAR) remote sensing technology.

For my analysis of the Big Laurel Creek – Whitetop Laurel Creek watershed, I have walked the watershed and photographed key locations that will be addressed in a future blog post.  In addition, I conducted the hydrologic analysis for the Mapping and Delineating the Big Laurel Creek – Whitetop Laurel Creek Watershed blog post on 28 September 2025 using three resources available on-line for watershed visualization.  This blog post will describe the procedure that I followed for that visualization.

 

 

Figure 1.  Visualization of the the Big Laurel Creek – Whitetop Laurel Creek watershed

 

The resources used to develop the watershed visualization, as shown in Figure 1 are:

1.       The U.S. Geological Survey’s (USGS) StreamStats

2.       The U.S. Geological Survey’s (USGS) LidarExplorer

3.       The non-governmental organization website, SpatialReference.org

4.       The commercial software program ArcGIS Pro developed by ESRI, a leading geographic information system (GIS) technology.  Use requires a license.

5.       The U.S. Army Corps of Engineers (USACE) Hydrologic Engineering Center's River Analysis System (HEC-RAS) RAS Mapper software.

I have included information and internet locations for each of these resources in the paragraphs below.

1.  From the USGS StreamStats website StreamStats | U.S. Geological Survey, “StreamStats provides access to spatial analytical tools that are useful for water-resources planning and management, and for engineering and design purposes. The map-based user interface can be used to delineate drainage areas, get basin characteristics and estimates of flow statistics, and more. Available information varies from state to state… StreamStats is a Web application that provides access to an assortment of Geographic Information Systems (GIS) analytical tools that are useful for water-resources planning and management, and for engineering and design purposes. The map-based user interface can be used to delineate drainage areas for user-selected sites on streams and then get basin characteristics and estimates of flow statistics for the selected sites anywhere this functionality is available. StreamStats users also can select the locations of U.S. Geological Survey data-collection stations, shown as triangles on the StreamStats map, and get flow statistics and other information for the stations. The types of flow statistics that are available vary from state to state. A variety of additional tools are available for discovering information about streams and the activities along them.”

 2.  From the USGS LidarExplorer website LidarExplorer | U.S. Geological Survey , “LidarExplorer is an online application that allows users to search and visualize Light Detection and Ranging (lidar) and its derived products. Users can find lidar, Digital Elevation Model (DEM), topobathymetric, and orthorectified radar image (ORI)… The LidarExplorer was created primarily to enable identification of lidar projects having 3D visualization enabled, giving users a mechanism to visualize the Lidar through web-based 3D viewers.”

3.  From the SpatialReference.org website (Home -- Spatial Reference), “SpatialReference.org is a comprehensive online resource dedicated to providing detailed information and reference materials on spatial coordinate reference systems.  This website is essential for geospatial professionals, GIS developers, and cartographers, providing an extensive database of spatial reference systems used globally.  The website allows users to search, access, and implement various spatial references easily.  A wide array of coordinate reference systems, such as WGS 84 or NAD83(2011) geographic systems, thousands of projected systems (like UTM zones), as well as vertical systems like NAVD88 are supported.”

4.  From the ESRI website Desktop GIS Software | Mapping Analytics | ArcGIS Pro website, “ArcGIS is a comprehensive geospatial platform for professionals and organizations. It is the leading geographic information system (GIS) technology… ArcGIS Pro is the premier desktop geographic information system (GIS) application. Crafted with user-driven innovations, it offers unparalleled tools and capabilities that support your work. Users can maintain spatial data effectively; generate stunning 2D, 3D, and 4D visualizations; and conduct advanced mapping analytics. The seamless data sharing within the ArcGIS system fosters valuable GIS solutions and insights.”

5.  From the USACE HEC-RAS Mapper website, https://www.hec.usace.army.mil/confluence/rasdocs/rmum/latest/introduction-and-overview , “The HEC-RAS Mapper module is an interface accessed from the main HEC-RAS program and provides a geospatial visualization of HEC-RAS geometry, simulation results, and other pertinent geospatial data to assist users to efficiently create river hydraulic models.”  ... A very useful exercise to understanding and developing a simple one dimensional (1D) HEC-RAS hydraulic model, with terrain visualization using HEC-RAS Mapper is provided by this tutorial available from Purdue University, Indiana, USA.  “The objective of this exercise is to learn the basic functions of RAS Mapper in HEC-RAS to create a 1D model of a river system.  Students are expected to have a basic understanding of hydraulics, open channel flow and GIS functions.”

 

I hope to create a step-by-step guide for developing a watershed visualization like Figure 1 in a future blog post, but for now, the following is the general procedure:

1.  Determine the latitude-longitude geographical coordinates of the watershed terminus.  The terminus is location where outflow stream of the watershed joins another stream of similar size and magnitude to form the next larger watershed.

2.  Using this location in StreamStats, delineate the watershed by first selecting the state of interest when prompted, and then zoom to maximum resolution (level 16) which will show all perennial and intermittent streams as pixelated blue lines.  Select the appropriate blue line pixel for the terminus location; several attempts may be required for the program to recognize the cursor location.

3. Once the watershed is delineated, select download basin as a shapefile.  Proceed to #4. 

… If you want the watershed Basin Characteristics and Regression Based Scenarios (Peak-Flow Statistics, Bankfull Statistics, etc.), you can build the report by following the StreamStats prompts.  I recommend that you print the report as a pdf.  This report is very useful for analysis. 

4.  Navigate to the 3DEP LidarExplorer at USGS Lidar Explorer Map.    Using the geography of the watershed from the delineation from StreamStats, select “Show where Lidar is available”.  If Lidar is available for the watershed of interest, select “Define Area of Interest” (AOI) and hold the Ctrl key down while dragging a box on the map or use the AOI widget to draw a box on the map.  Try to limit the AOI rectangle to only the watershed shape to avoid downloading unneeded digital elevation model (DEM) files.  Select the dropdown for ‘Downloadable Products within AOI” and select all 1m DEM available in AOI.  Since the 1m DEMs are sometimes fragmented, especially for an AOI that cross state lines, be sure to download all of the DEM listed.

5.  Navigate to the SpatialReference.org website and select the ESRI references and search by state.  Select the projection (.prj) file desired.  I recommend using the NAD_1983_2011_StatePlane projection if you plan to use US customary units for future watershed analysis.

6.  Open the ArcGIS Pro program if you have a license.  Using the 1m DEM files downloaded from the 3DEP LidarExplorer, merge these into a single geotiff (geographical tagged image file format) using the ArcGIS Pro geoprocessing command “Merge Raster”.  Make sure to set the projection of the new raster to match the projection downloaded in step #5.  Using the shapefile downloaded from StreamStats in step #3, use the “Raster Clip function” to create a raster of just the watershed defined by the shapefile.

7.       Using the watershed shape raster created in step #6 and following the guidance in the Purdue HEC-RAS Mapper tutorial, generate the visualization in RAS Mapper of the new watershed that is similar to Figure 1.