Introducing Streamflow Viewer (Beta)
The Streamflow Viewer (beta) Instant app template allows app viewers fast visualization to explore streamflow forecasts. This new app incorporates the latest Living Atlas GEOGloWS streamflow forecasts, which include an interactive graph showing streamflow forecasts through time. The app automatically incorporates the streamflow forecast service, making it simple for anyone with an ArcGIS Online map to publish a web application with an integrated streamflow layer and forecast hydrograph.
Setup the app
In Streamflow Viewer, you can add any map to the application. There are no data requirements for the app. You do not need to add the streamflow forecast to your webmap; it will be added automatically when you create the app. The app can be created from the Instant Apps home page, the Create app option in the Map Viewer, or the Create web app option from the item details page of a web map.
Once you have your map added to the app, you can begin configuring the other available settings:
- Header —Choose to include or not include a header in the app.
- Basemap toggle – Choose a basemap to switch to
- Theme settings—Change the app's appearance by applying dark or light mode, adding a logo to the header, and using custom or predefined colors to style specific elements.
- Basic map navigation tools —Include Home, Zoom tools, Legend, or Search in the map.
- Sharing—Add options for app users to share the app. If a stream’s popup and chart are open, the app will be shared with that specific stream. Optionally, include embed and social sharing.
This is not a complete list of available options. Disable express mode and/or use the search settings option to find additional options.
Interact with the graph and time slider.
Clicking on a stream segment will generate a graph of the segment. The graph uses the same 10-day forecast at 3-hour intervals described above for the map. The mean value of the forecast is shown in blue, and a probability range is shown in grey. The range is the 25% to 75% values of the 51 ensemble members. The return period colors and values from the streamflow service are also shown as the corresponding background color of the graph.
Use the time slider to animate the forecast on the map and the graph. The streamflow forecast service will update as the slider plays.
Road map
Streamflow Viewer (beta) will receive additional updates in future releases. These will include support for the US model and the addition of the attribute filter component to the app.
URL Params
Until the attribute filter is added, you can filter out streams using a URL parameter. This will allow app authors to focus the streams on a specific area. Below are the parameters accepted.
Filter by country of origin of a steam
Show only streams that originate in a specific country. To filter streams by the origin of the river use rivercountry= and the name of the country
In this example, https://webapps.maps.arcgis.com/apps/instant/streamflowviewer/index.html?appid=d2e7e9325f3c4dd096c07..., limit the streams to those whose flow originates in the United States but misses some upstream reaches that start in Mexico and Canada.
Filter by the country a stream ends in
Filter streams by the country the stream ends in. To filter streams by the country the stream ends in use outletcountry=.
A common use case to make a map for a country and ensure you get all the stream reaches of interest is to use the expression which contains both rivercountry and outletcountry.
In this example https://webapps.maps.arcgis.com/apps/instant/streamflowviewer/index.html?appid=d2e7e9325f3c4dd096c07... includes both rivercountry and outletcountry, which is the way to get all stream reaches of interest for a county.