Do you have a question about StreamStats? Check out our curated list of frequently asked questions from other StreamStats users.
A gray background can mean one of two things. Either you are zoomed in beyond the maximum resolution allowed for your chosen base map, or the web service providing the base map layer is experiencing issues.
StreamStats version 4 is a map-based web application that incorporates a Geographic Information System (GIS) to provide users with access to an assortment of analytical tools that are useful for water resources planning and management, engineering and design purposes.
StreamStats offers a variety of streamflow statistics and basin characteristics but because the application is built on state/regional data, the products offered for each will vary.
The most recent interpretive statistics that are available for streamgages within a state generally are in reports that are cited on our State and Regional-Based Info page for that state, if that state has been implemented. The State and Regional-Based Info page can be accessed through our left-hand menu or directly at https://www.usgs.gov/streamstats/state-and-region-based-info.
The blue pixelated lines are what we call the "stream grid" or "synthetic stream grid", which are used mainly as a guide for delineation. If you click off of these lines, your delineation may only include a few grid cells near the point you clicked. The grid lines are not visible until you have reached zoom level 15.
In a series of estimated flow statistics for an ungaged site, such as peak-flows at various recurrence intervals or flow-duration statistics, why do I sometimes get estimates for lower flows that are higher than estimates for higher flows?
The regression equations that are used to estimate flow statistics for ungaged sites were developed using computed streamflow statistics and measured basin characteristics for a selected group of streamgages, in other words, a small sampling of streamgages. These small samplings cannot capture all of the variability in a region.
What is the smallest drainage area that StreamStats can delineate accurately, and can I rely on flow estimates for small areas?
The accuracy of drainage-area delineations for small areas depends on accuracy and scale of the elevation data used in StreamStats for the delineations. The elevation data that StreamStats uses for most areas are from the USGS 3D Elevation Program dataset, which is a seamless national elevation dataset that is refreshed regularly as new data are made available.
If I use StreamStats at an existing gage location, will I get the same results as if I computed statistics using the gage records?
The short answer is: it depends which tool you use.
StreamStats is still expanding to new areas but if your state/region isn't included, here are a few other options that may help.
StreamStats is still expanding with new states/regions. If you are looking for a study area that doesn't exist in the interface we can provide direction on how to get your desired study area implemented.
The StreamStats application uses a generalization process to reduce the resolution of a basin for display purposes. Rest assured the computations are calculated on the full-resolution delineation.