Maine StreamStats: Streamflow Estimates for Any Stream in Maine, Online

Maine StreamStats is a free web application from the U.S. Geological Survey, built with the Maine Department of Transportation, that calculates basin characteristics and streamflow statistics for any point a user picks on a stream in Maine. Anyone online can outline the watershed on the fly and estimate a wide range of statistics for ungaged sites — places with no streamgage. Estimates come from regression equations or from data at similar gaged sites on the same stream. It is part of the national StreamStats application used in many states.

The USGS reports behind the tool give the regression equations, their errors, how they were developed and how the basin characteristics were measured, along with their limits — for example, every equation applies only to ungaged, unregulated, rural streams in Maine.

How it works

1. Pick a site on a stream.
2. StreamStats delineates the basin draining to it.
3. It reports the flow statistics and basin characteristics.

Basins are outlined using the National Hydrography Dataset and Watershed Boundary Dataset (both the 24K versions) and 10-metre elevation data from the National Elevation Dataset. Where high-resolution lidar exists in Maine it has been merged in: those elevation models are accurate to about 1 foot vertically, against 10 to 20 feet for the 10-metre data. StreamStats shows where lidar was used, and more will be added as it becomes available.

What it can estimate

Flows:

• peak flows with recurrence intervals from 1 to 500 years;
• monthly and annual mean and median flows;
• the 7-day, 10-year low flow;
• June median flows for southern Maine, and August median flows for southern, eastern coastal and northern Maine;
• bankfull discharge, width, depth and area for streams in central and coastal Maine.

Basin characteristics: drainage area, the share of sand-and-gravel aquifer, the percentage of storage in lakes, ponds and wetlands, mean annual and mean winter precipitation, distance from the coast to the centre of the basin, and mean basin elevation.

More

StreamStats also retrieves previously published statistics, basin characteristics and descriptions for USGS streamgages, and can trace a stream upstream or downstream from a chosen point to find connected reaches. Outlined basins can be edited, saved and downloaded for use in other GIS software.

Sources

• Lombard, P.J., 2015, Maine StreamStats — A water-resources web application: U.S. Geological Survey Fact Sheet 2015–3014, prepared in cooperation with the Maine Department of Transportation. https://pubs.usgs.gov/publication/fs20153014
• The application: StreamStats.
• Figures: U.S. Geological Survey screen captures on The National Map base.
• Rewritten in hubnx's own words.