Maine StreamStats—A Water-Resources Web Application

Maine StreamStats (http://streamstats.usgs.gov), a geographic information system-based Web application 

of the U.S. Geological Survey (USGS), is a tool for calculating basin characteristics and streamflow statistics for 

user-selected sites on streams in Maine.

Figure 1. Screen capture from Maine StreamStats Web application showing delineated basin and available map layers.

Introduction

Maine StreamStats is a tool that any user with Internet 

access can use to delineate a basin on the fly and estimate 

a wide variety of streamflow statistics for ungaged sites on 

rivers and streams in Maine (figs. 1 and 2). Estimates are based 

on regression equations or are from data from similar gaged 

locations on the stream. Maine StreamStats is based on a 

national StreamStats application that can be used for streamflow 

estimates in many other states across the country (Ries and 

others, 2008).

Reports referenced in this fact sheet present the regression 

equations used to estimate the flow statistics, describe 

the errors associated with the estimates, and describe the 

methods used to develop the equations and to measure the 

basin characteristics used in the equations. Limitations of the 

methods are also described in the reports; for example, all of the 

equations are appropriate only for ungaged, unregulated, rural 

streams in Maine.

Data Used for Basin Delineations

Basin delineations in StreamStats are based on the 

integration of the National Hydrography Dataset (24K NHD), 

the Watershed Boundary Dataset (24K WBD), and the 10-meter 

resolution digital elevation model (DEM) data from the 

National Elevation Dataset (NED).

High resolution DEMs from light detection and ranging 

(lidar) data are available for some areas of Maine and were 

incorporated into the DEM for the delineating of basins. The 

DEMs for these areas have a 1-foot vertical accuracy and are 

much more accurate than the 10-meter DEMs with 10- to 20-foot 

vertical accuracies with which they are merged. StreamStats 

indicates where lidar was used. Additional lidar data will be 

incorporated into StreamStats as they become available.

Flow Estimates and Basin Characteristics

Streamflow statistics that can be output from the 

tool include peak flows with 1- to 500-year recurrence 

U.S. Department of the Interior

U.S. Geological Survey

ISSN 2327-6932 (online)

http://dx.doi.org/10.3133/fs20153014

Fact Sheet 2015–3014

February 2015
A

Step 1:

User selects ungaged site

B

Step 2:

StreamStats delineates basin

C

Step 3:

StreamStats outputs flow statistics

Figure 2. Process within StreamStats for A, selecting a site, B, 

delineating a basin, and C, obtaining streamflow statistics. The 

arrow and point indicate an ungaged site; PKX, peak flow with an 

X-year recurrence interval; ft3

/s, cubic feet per second.

intervals (fig. 2C); monthly and annual mean and median flows; 

7-day 10-year low flows; June median flows for southern Maine; 

August median flows for southern, eastern coastal, and northern 

Maine; and bankfull discharge, width, depth, and area for 

streams in central and coastal Maine.

Basin characteristics that can be calculated within 

StreamStats include the drainage area, fraction of sand and 

gravel aquifer, percentage of storage in waterbodies and 

wetlands, mean annual precipitation, mean winter precipitation, 

distance from the coast to the basin centroid, and mean 

basin elevation.

Additional Functionality

StreamStats can also be used to obtain previously published 

streamflow statistics, basin characteristics, and descriptive 

information for USGS streamgages and to search upstream or 

downstream from a selected site to identify connected stream 

reaches. Delineated basins can be edited, saved, and downloaded 

for use in other geographic information system applications.

Selected References

Dudley, R.W., 2004a, Estimating monthly, annual, and low 

7-day, 10-year streamflows for ungaged rivers in Maine: 

U.S. Geological Survey Scientific Investigations Report 

2004–5026, 22 p.

Dudley, R.W., 2004b, Hydraulic-geometry relations for rivers in 

coastal and central Maine: U.S. Geological Survey Scientific 

Investigations Report 2004–5042, 30 p.

Hodgkins, G.A., 1999, Estimating the magnitude of peak flows 

for streams in Maine for selected recurrence intervals: U.S. 

Geological Survey Water-Resources Investigations Report 

99–4008, 45 p.

Lombard, P.J., 2004, August median streamflow on ungaged 

streams in eastern coastal Maine: U.S. Geological Survey 

Scientific Investigations Report 2004–5157, 15 p.

Lombard, P.J, 2010, June and August median streamflows 

estimated for ungaged streams in southern Maine: U.S. 

Geological Survey Scientific Investigations Report 

2010–5179, 16 p.

Lombard, P.J., Tasker, G.D., and Nielsen, M.G., 2003, August 

median streamflow on ungaged streams in eastern Aroostook 

County, Maine: U.S. Geological Survey Water-Resources 

Investigations Report 03–4225, 20 p.

Ries, K.G., III, Guthrie, J.D., Rea, A.H., Steeves, P.A., and 

Stewart, D.W., 2008, StreamStats—A water resources 

Web application: U.S. Geological Survey Fact Sheet 

2008–3067, 6 p. 

—By Pamela J. Lombard

For more information concerning this report, contact:

Office Chief

Maine Office, New England Water Science Center

U.S. Geological Survey

196 Whitten Road

Augusta, Maine 04330

(207) 622-8201

dc_me@usgs.gov

or visit our Web site at http://me.water.usgs.gov

Prepared by the Pembroke Publishing Service Center.