Skip Links

USGS - science for a changing world

Scientific Investigations Report 2010–5179

Prepared in cooperation with the Maine Department of Environmental Protection

June and August Median Streamflows Estimated for Ungaged Streams in Southern Maine

By Pamela J. Lombard

ABSTRACT

Right-click to download or Save As (1.53 MB)

Methods for estimating June and August median streamflows were developed for ungaged, unregulated streams in southern Maine. The methods apply to streams with drainage areas ranging in size from 0.4 to 74 square miles, with percentage of basin underlain by a sand and gravel aquifer ranging from 0 to 84 percent, and with distance from the centroid of the basin to a Gulf of Maine line paralleling the coast ranging from 14 to 94 miles. Equations were developed with data from 4 long-term continuous-record streamgage stations and 27 partial-record streamgage stations. Estimates of median streamflows at the continuous-record and partial-record stations are presented. A mathematical technique for estimating standard low-flow statistics, such as June and August median streamflows, at partial-record streamgage stations was applied by relating base-flow measurements at these stations to concurrent daily streamflows at nearby long-term (at least 10 years of record) continuous-record streamgage stations (index stations). Weighted least-squares regression analysis (WLS) was used to relate estimates of June and August median streamflows at streamgage stations to basin characteristics at these same stations to develop equations that can be used to estimate June and August median streamflows on ungaged streams. WLS accounts for different periods of record at the gaging stations.

Three basin characteristics—drainage area, percentage of basin underlain by a sand and gravel aquifer, and distance from the centroid of the basin to a Gulf of Maine line paralleling the coast—are used in the final regression equation to estimate June and August median streamflows for ungaged streams. The three-variable equation to estimate June median streamflow has an average standard error of prediction from -35 to 54 percent. The three-variable equation to estimate August median streamflow has an average standard error of prediction from -45 to 83 percent. Simpler one-variable equations that use only drainage area to estimate June and August median streamflows were developed for use when less accuracy is acceptable. These equations have average standard errors of prediction from -46 to 87 percent and from -57 to 133 percent, respectively.

First posted October 21, 2010

For additional information contact:
Director
U.S. Geological Survey
Maine Water Science Center
196 Whitten Road
Augusta, Maine 04330
(207)622-8201

http://me.water.usgs.gov/

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

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., at http://pubs.usgs.gov/sir/2010/5179/.



Contents

Abstract

Introduction

Purpose and Scope

Description of Study Area

Data Collection and Analysis

Station Selection and Streamflow Measurements

Basin Characteristics

Computation of June and August Median Streamflows at Long-Term Continuous-Record Stations

Estimation of June and August Median Streamflows at Partial-Record Stations

June and August Median Streamflows Estimated for Ungaged Streams

Statistical Methods

Ordinary Least-Squares Regression

Weighted Least-Squares Regression

Average Standard Error of Prediction

Three-Variable Models

One-Variable Models

Summary and Conclusions

Acknowledgments

References Cited



Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://pubs.usgs.gov/sir/2010/5179/
Page Contact Information: Contact USGS
Page Last Modified: Thursday, 10-Jan-2013 19:18:42 EST