User Instructions
Please help us conserve our server system resources and close the Interactive Map window when you are finished using it. Doing so will help ensure system availability for all users. Thank you.
The new network navigation, and estimating flows based on similar gages have not yet been implemented for all states. These processes will be added in the near future.
Also, we recommed not to bookmark the actual interactive map because the URL can change. If you do bookmark, please use the state intro page instead - this URL will not change. For example, Massachusetts state intro page is http://water.usgs.gov/osw/streamstats/massachusetts.html
The Help button 
to the far right of the toolbar above the map frame launches a new window that contains a help facility that provides detailed instructions on general use of the interface, such as using the toolbar, identifying features, using the magnifier, displaying map layers, etc. Users should review this information before attempting to use StreamStats. The information provided through the Getting Started and Quick Tour links in the help facility are particularly helpful. This help facility is somewhat generic, and does not provide instructions for use of the custom tools built into StreamStats. Instructions for those tools are provided below. NOTE: Users should always wait until processing is completed and the map is re-drawn before attempting to do additional work with StreamStats.
Sites of interest may be located by use of the Zoom In button to the top left of the toolbar above the map frame or by use of the Zoom To pull-down menu toward the right end of the toolbar.
Use of the Zoom In button: 
- Click on the Zoom In button.
- Move the cursor over the map, 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 must be at 1:24,000 or greater to select a site for basin delineation. This corresponds to the scale bar in the lower right corner of the map indicating a maximum distance in the positive direction of the bar of 0.4 miles.
Use of the Zoom To tools: 
The Zoom To pull-down list near the center of the toolbar provides access to three separate tools for zooming in to specified locations. These tools allow users to zoom into a provided latitude and longitude, a place name, or a National Hydrography Dataset (NHD) reach code. To use one of these tools:
- Click on the down arrow at the right side of the Zoom To pull-down menu to select the desired mode for zooming.
- If a latitude and longitude is selected, a pop-up window will appear that contains boxes in which the latitude and longitude of the desired location can be entered, in decimal degrees. Click on the Zoom To button in the pop-up window to zoom to the desired location. Although longitudes in the Western Hemisphere are negative, type the longitude in as a positive value.
- If a place name is selected, a pop-up window will appear that contains a box in which the user can enter all or part of the desired name. Below this box is a pull-down list of feature types on which the search will be done. Select the feature type that is most closely associated with the desired place name. For example, users should select a feature type of populated place if they want to zoom into a city or town. The search can be further refined by selected the appropriate state and county from the available pull-down lists. When all selections have been made then click on the Submit Query 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 list will be provided of the names of all places matching the given name. Determine from the Feature Name the entry that most closely matches the desired location, and then click on Zoom in the first column of the table in the row for the selected entry to cause the map to zoom into the location.
- If a reach code is selected, then a pop-up window will appear in which the code can be entered. Users should first select the resolution of the NHD dataset to which the site of interest is referenced (medium, high, or local), and then enter the 14-digit reach code and the measure (percentage along the reach). Click on the Zoom To button in the pop-up window to zoom to the specified location.
Zooming to a specified scale: 
To the right of the Zoom To pull-down list is another pull-down list in which the current scale is shown. To change scales with the map centered on the present location, click on the down arrow to the right side of the pull-down list and select the desired scale. Note that to delineate a drainage-basin boundary for an ungaged site, the map must be zoomed into a scale of at least 1:24,000.
Selecting a site and delineating a watershed:
When an appropriate scale is reached, 1:24000 or greater, the map frame displays either a dark blue grid or a dark blue line to represent the stream network, depending on which state application is used and the spatial data on which it is based. The stream network was derived entirely or in part from digital elevation data, and does not always agree exactly with the streams shown on the topographic base map.
- Click on the Watershed Delineation from a Point button.
- Click on the stream network grid cell or a point on the line 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 magenta on the map.
- A quick check of the boundary can be done by turning off the basemap layer and turning on the NHDFlowline or Dendritic Stream Network layer to assure that no streams cross the basin boundary, which is an indication that something may be wrong.
- A detailed check of the boundary can be done by use of the Zoom to Previous Extent
and Pan 
buttons to compare the delineated boundary to the topography and streams shown on the base map. - 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 Hide/Show Last Delineation
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:
Basin boundaries determined by StreamStats can be edited to add or remove parts of the delineated drainage basin. Users may want to modify the boundaries to correct errors in the delineations resulting from inaccuracies in the spatial data used to determine them, or they may want to determine the effects of proposed land-use changes or changes that were already made but are not reflected in the topographic map and spatial data.
Editing of basin boundaries is done by use of a combination of the Edit a delineated basin tool button 
and the adjacent shape selection menu. 
- After the initial basin delineation is completed, zoom in closely to the area that needs to be edited.
- Click on the Edit a Delineated Basin tool button and then select Add Shape or Remove Shape and click OK.
- Visualize a polygon that will entirely enclose the area to be added or removed.
- Click the left mouse button once at a vertex of the desired polygon, and then once on each successive vertex. The sides of the polygon will be drawn as the mouse is moved from vertex to vertex.
- Click twice on the final vertex to end editing. StreamStats will then begin processing and re-draw the basin area to reflect the changed boundary.
- If the basin is large, then to assure accurate editing, complete a series of small edits while zoomed in closely rather than relying on a single edit while zoomed far out.
- After editing the basin boundary, the Basin Characteristics, Estimate Flows Using Regression Equations, and Estimate Flows Based on Similar Gages tools will operate using the edited basin. Reports will indicate that the basin was edited.
Getting Streamflow Statistics for the Ungaged Site:
Estimates of streamflow statistics for user-selected ungaged sites can be obtained by two methods in StreamStats. The Watershed Delineation from a Point tool must be used first to obtain the drainage-basin boundary for the point of interest before either of the flow-estimation tools may be used. The Estimate Flows Using Regression Equations 
tool provides estimates by measuring needed basin characteristics and solving USGS-developed regression equations. The Estimate Flows Based on Similar Streamgaging Stations 
tool estimates streamflow statistics by applying the flows per unit area for streamflow statistics at a nearby gaging station to the drainage area for the ungaged site. The theoretical basis for these methods and the outputs provided by StreamStats are explained in more detail on the Ungaged Sites page.
To obtain estimates based on USGS regression equations:
- After basin delineation and any editing are complete, click on the Estimate Flows Using Regression Equations tool 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.
- 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.
To obtain estimates based on flows at nearby similar gages:
- After basin delineation and any editing are complete, click on the Estimate Flows Based on Similar Streamgaging Stations tool button . A dialogue window will appear that has a check box allowing the user to choose whether on not to allow use of regulated gaged sites in the analysis.
- Choose whether or not to allow use of regulated gaged sites, and then click on Estimate flows to get estimates or on Close if flow estimates are not desired.
- The decision of whether or not to use regulated sites in the analysis should be made carefully. If estimates of natural flows are desired, then regulated stations should not be used. If the user-selected site is downstream from a dam, a diversion, or some other activity that has a major effect on streamflow, then estimates based on regulated streamgaging stations may provided more realistic estimates of actual flow conditions at the user-selected site than natural flow estimates.
- If regulated stations are used in the analysis, then users should also get a StreamStats report of the published streamflow statistics for the streamgaging station and review the publication from which the statistics were obtained to understand any special conditions used to compute the statistics for the station. In some cases, the computed statistics may have been determined from a period during which the streamflow was unregulated at the station. Directions for obtaining reports of streamflow statistics for USGS data-collection stations are provided below.
- Estimates usually will be provided only if the drainage area for the user-selected site is within 0.5 to 1.5 times the drainage area for an upstream or downstream streamgaging station.
- This process usually should be done after regression estimates are obtained because if regression estimates have been obtained first, then StreamStats will combine the regression estimates with the estimates based on the nearby streamgaging stations to provide improved estimates. Improved estimates are available only when the years of record are available in the StreamStats database of streamflow statistics for the streamgaging station and the equivalent years of record are also available for the regression estimates.
Editing Parameters and Recomputing Flows:
The Edit Parameters and Recompute Flows button 
allows users to modify the basin characteristics that were measured by StreamStats in the Estimate Flows Using Regression Equations, which must be completed before the Edit Parameters and Recompute Flows tool can be used. Upon selecting this tool, a pop-up window will appear that lists all of the basin characteristics that were used to solve the regression equations for the selected location. Users can type in new values for any of the basin characteristics. Click on the Recompute Flows button and a new ungaged site report will appear that looks the same as the report from the Estimate Flows Using Regression Equations process except that the title indicates that edited parameters were used to obtain the flow estimates.
The Edit Parameters and Recompute Flows process is useful for testing the sensitivity of the regression equations to changes in the basin characteristics used as parameters in the equations. Multiple scenarios can be tested in succession by (1) clicking with the right mouse button on the output window to cause a menu to appear, (2) selecting Back from the menu to cause the parameter editing window to reappear, (3) modifying the characteristics again, and (4) clicking on the Recompute Flows button to obtain new estimates. The Edit Parameters and Recompute Flows process also can be used to determine changes in flow that can be expected due to a planned or natural change in a parameter. For example, the drainage area could change as a result of mining operations, or a change in mean annual precipitation could be expected as a result of anticipated climate change.
Getting Additional Basin Characteristics for an Ungaged Site:
The basin characteristics provided in the output from the Get Statistics tool are limited to those needed to solve the regression equations that are available at the user-selected point. Often, additional basin characteristics can be obtained by use of the Basin Characteristics tool button 
.
- After basin delineation and any editing are complete, click on the Basin Characteristics tool button. A pop-up window will appear, providing a list of the basin characteristics that are available for the location.
- 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 Gaging Station Information tool button
when 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.
Stream Network Navigation (Network Tracing):
The theory of network navigation is explained on the Network Navigation page. StreamStats contains three tools for network navigation, Configure NHD, Trace From Outlet, and Ad Hoc Trace. The stream network on which the trace is to be performed should be displayed in the user interface before attempting a trace. If a site already has been selected and a drainage-basin boundary has been obtained:
- Click on the Configure NHD Trace tool button
to display a dialogue window that allows specification of the network upon which tracing (searching upstream or downstream) will be done, the direction of the trace, and the map layers of events that will participate in the trace. - Select the network, trace direction, and map layers, then click on the OK button.
- Click on the Trace from Outlet tool button
to perform the trace and wait for the results. - A pop-up Web-browser window will appear with the results from the trace, and the map frame will redraw, with the stream reaches identified in the trace highlighted.
- Click on the fields with hyperlinks in the output tables to obtain additional information.
If a watershed basin has not already been delineated:
- Click on the Configure NHD Trace tool button and select the network, trace direction, and map layers, as described above.
- Click on the Ad Hoc Trace tool button
. - Click on any point on the stream network and wait for the results. (You should be zoomed in to scale at which the stream network can be clearly defined before doing this.)
In either case, after the network trace has been completed a pop-up Web-browser window will appear with the results from the trace, and the map frame will redraw, with the stream reaches identified in the trace highlighted. Click on the fields with hyperlinks in the output tables to obtain additional information.
To clear all network trace results, click on the 'Clear Selected Features from NHD Trace' button 
.
Raindrop Trace to Network:
This tool traces from the point chosen by the user using the underlying flow direction grid associated to that HUC until intersecting the current active network layer, the trace then follows the network downstream to the outlet.
How to use the function:
- Click the Raindrop Trace to Network tool (
) to activate the tool. - Click on the map at the location where you want to start the trace.
The tool traces from the user specified point using the underlying flow direction grid until intersecting with the active network. It then traces downstream along the network. The blue point represents the point clicked by the user. The green point is the location where the trace first intersects the network.
The function also displays the reachcode code and measure of the location where the trace first intersect the network layer.
Trace Network Path within Watershed and Show Profile:
This tool traces the network path and generates the profile along the main flow path from the user specified trace point to the watershed outlet. The watershed must be entirely located within one HUC.
How to use the function:
- Delineate a watershed first that it is located entirely within one HUC.
- Click the Trace Network Path within Watershed and show Profile tool
. - Click on the map at the location where you want to start the trace.
The tool displays the path in red between the user specified (blue point) and the watershed outlet (yellow star).
Also, a graph is generated that shows the profile corresponding to the flow path.
Terrain Profile:
This tool generates the terrain profile of the user specified points using the underlying Digital Elevation Model (DEM) grid.
How to use the function:
- Click the Terrain Profile
tool. - Click points on the map that will be used to generate profile.
This tool displays the profile path in red, user specified points as green points.
Also, a graph is generated that shows the profile corresponding to the user specified points.
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. These shapefiles will be needed to verify what was done if there is any reason to question the results from StreamStats.
- After first thoroughly checking the delineated basin polygon and getting the streamflow estimates, click on the Download tool button
. A dialog window will appear. - Enter a watershed name in the dialogue window and then click on the Download button to download a zip file that contains the shapefile for the site or click on the Close button to exist without obtaining a shapefile.
- After clicking on the Download button, the name of the zip file will appear in the dialogue window. Click on the name and save the file to a location on your computer.
Print the view in the Map Frame:
- The view in the Map Frame may be printed using the Print button
. - A floating panel will appear, allowing users to enter a title for the map, a comment, a print format template (landscape, portrait, etc.), and a theme. The only theme choice currently is StreamStats. Click on the Create Print Page button in this window after the selections are made.
- Another pop-up window will appear showing the view from the Map Frame and a legend of the displayed map layers.
- The map can be printed by clicking on the Print button on the map or selecting File and then Print from the web browser menu bar at the top of the window.
