User Instructions
Sites may be located by use of the Zoom In button to the top left of the map frame or by use of the Zoom To tool to the right of the map frame. NOTE: Users should always wait until processing is completed and the map is re-drawn before attempting to do additional work with StreamStats.
Use of the Zoom In button:
- Click on the Zoom In button.
- Hold down the left mouse button and drag the cursor to outline a box over the area of the stream site of interest.
- Release the left mouse button and wait for the map to re-draw.
- The scale of the map, shown at the bottom right of the map frame, must be at 1:24,000 or greater to select a site.
Use of the Zoom To button:
- Click on the down arrow at the right side of the Zoom To pull-down menu to select the desired mode for zooming. Choices vary among state applications, and may include zooming to (1) a water feature, such as a stream or lake, (2) any named place that appears on USGS topographic maps, (3) a street address, or (4) a latitude and longitude.
- If a water feature is selected, the box below the Zoom To menu will display “Enter Water Resource Name.” In this box, type in the name of a water feature, then click on the GO button to the right of the Zoom To menu. If only one water feature matches the name given, the map frame will zoom to that feature. If more than one feature matches the given name, a small window will pop up to show the names of all features matching the given name. Select a feature from the list to zoom to that feature.
- If a latitude and longitude is selected, type in the degrees, minutes, and seconds of the coordinates in the boxes that will appear below the menu, and then click on the GO button to zoom to that location. Although longitudes in the Western Hemisphere are negative, type the longitude in as a positive value.
- If a place is selected, zooming can be done by two modes. Users can type in the name of a place in the box that will appear below the menu, and then click on the Go button. If only one place matches the name given, the map frame will zoom to the location. If more than one place matches the given name, a small window will pop up to show the names of all places matching the given name. Select a place name from the list to zoom to the location. Alternately, users can click on the Get List button to the right of the selection box. If this is done, a the selection box will turn into a scroll-down list of the place names in the State. Users can then select a place name from the list and click on the GO button to zoom to that location.
- If an address is selected, type in an address, and then click on the GO button to zoom to that location.
Selecting a site and delineating a watershed:
When an appropriate scale is reached , 1:24000 or greater, the map frame displays a dark blue grid representing the stream network. The stream grid was derived from digital elevation data and does not always agree exactly with the streams shown on the topographic base map.
- Click on the Watershed Delineation button .
- Click on the grid cell that is closest to the stream site of interest.
- StreamStats will begin processing to delineate the drainage boundary for the site of interest. When finished, the basin will be highlighted in green on the map and this message will appear:
- If the site was selected incorrectly or there is an obvious problem, click on Cancel to clear the boundary; otherwise click on OK.
- A second warning message will appear, with the following message:
- Check the boundaries of the basin by using the Last Extent and Pan buttons to compare the delineated boundary to the topography and streams shown on the base map. It is also a good idea to turn off the layers other than the streams and delineated basin.
- Users should particularly examine the delineation in the area nearest the selected point, as that is where problems are most likely to occur. An error is indicated if the delineated boundary does not follow the topographic divide or a stream on the base map crosses the boundary.
- If an error has occurred, see below to learn how to notify the StreamStats team about it. It may be possible to eliminate the error by using the Clear Polygon button to clear the boundary and selecting a new point for delineation just upstream or downstream from the previously selected point. If possible, avoid flat areas, such as the middles of lakes, wetlands, or broad valleys.
Editing Basin Boundaries:
Follow the steps below if a delineated boundary needs to be edited, clicking on the EditBasin button will result in a new window popping up on the user’s desktop.
- Zoom in tightly to the area that needs to be edited. You cannot zoom or pan in the edit window. If the basin is large, you can edit the boundary by doing a series of small windows sequentially before requesting new statistics.
- Click on Edit Basin. A new window will open. You have the option to add to the basin and/or remove from the basin.
- To add an area to the basin boundary, select the Add radio button and then draw an area to add to the original shape. The new polygon will be drawn with a red outline (default). The color for the outline, fill and vertex can be changed by selecting a new color/target combination from the drop down list.
- To remove an area to the basin boundary, select the Remove radio button and draw a new polygon representing an area to remove from the original polygon. This polygon will be blue by default.
- When finished drawing, right-click on the polygon. A new window will open.
- Select Editing Shape. The vertices will be displayed for the selected polygon. You can perform the following operations:
- A. Move an existing vertex by clicking on the vertex and dragging it to its new location).
B. Add a new vertex by clicking on a line.
C. Delete an existing vertex by clicking on the vertex and then on delete (note that you cannot delete the first vertex or any vertex if only 3 are remaining).
- A. Move an existing vertex by clicking on the vertex and dragging it to its new location).
- Right-click and select Stop Editing Shape to save the edits.
- Click on Submit to submit the edits. The window will close and the map will be updated with the new basin. Any layers previously created when computing parameters will be cleared (e.g. centroid, longest flow path) since they would be wrong for the new basin
- Repeat the process as many times as necessary on the basin
Getting Streamflow Statistics for the Ungaged Site:
- After delineation and any editing are complete, click on the Get Statistics button. StreamStats will determine what regression equations are available to estimate the streamflow statistics for the region.
- A pop-up window will appear showing descriptive information for the site, measured basin characteristics, estimated streamflow statistics, and indicators of the errors associated with the estimates. For a more in-depth discussion of the output, click here.
- The output should be printed or saved to a file as a record of the analysis. Click on the File menu of the browser window, and then click on Print to print the output, or click on Save As to save the output to a file on your computer.
Getting Statistics for a USGS Data-Collection Station:
- Zoom in to the area in which the station of interest is located.
- Click on the GageInfo button using a state application or on the StationInfo button if using the national data-collection station application.
- Click on a triangle on the map that indicates the station location.
- A pop-up Web-browser window will appear with the available information for the selected station.
Downloading Shapefiles:
- The StreamStats application allows the user to download shapefiles of the delineated watershed and point. The shapefiles can be displayed and used for further analysis in other GIS applications.
- Shapefiles should be retained to serve as documentation of the exact point that was used in the delineation and the resulting watershed polygon. If there is any reason to question the results from StreamStats, these shapefiles will be needed to verify what was done.
- After first thoroughly checking the delineated basin polygon and getting the streamflow estimates, the user should click on the Download button to download the shapefiles.
Print the view in the Map Frame:
- The view in the Map Frame may be printed using the Print button.
- A pop-up window will appear, allowing users to enter a name for the map and to choose the print size. Click on the Create Print Page button in this window.
- Another pop-up window will appear showing the view from the Map Frame and a legend of the displayed map layers.
