Herbicide Concentrations in and Loads Transported by the Conestoga River and Pequea Creek, Lancaster County, Pennsylvania, 1992-95
Herbicide Concentrations in and Loads TransportedHerbicide by the Concentrations Conestoga River in And andPequea Loads Creek, Transported Lancaster County, by the Pennsylvania, 1992-95Conestoga River and Pequea Creek, Lancaster County, Pennsylvania, 1992-95 U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 97-4124 Prepared in cooperation with the SUSQUEHANNA RIVER BASIN COMMISSION Herbicide Concentrations in and LoadsHerbicide Transported Concentrations by the Conestoga in River and Pequeaand Loads Creek, Transported Lancaster County, by the Pennsylvania,Conestoga 1992-95 River and Pequea Creek, Lancaster County, Pennsylvania, 1992-95 by Lloyd A. Reed and Edward H. Koerkle, U.S. Geological Survey, and Charles S. Takita, Susquehanna River Basin Commission U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 97-4124 Prepared in cooperation with the SUSQUEHANNA RIVER BASIN COMMISSION Lemoyne, Pennsylvania 1997 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director For additional information Copies of this report may be write to: purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Branch of Information Services 840 Market Street Box 25286 Lemoyne, Pennsylvania 17043-1586 Denver, Colorado 80225-0286 ii CONTENTS Abstract . 1 Introduction . 2 Purpose and scope . 2 Description of study area. 3 Acknowledgments . 4 Methods of data collection and analysis. 5 Data-collection methods . 5 Laboratory methods . 6 Quality-assurance procedures . 7 Computation of loads. 9 Computation of loads by using the traditional method of hydrograph subdivision . 10 Computation of loads by using the relation between water discharge and constituent concentration . .13 Computation of loads by using the minimum variance unbiased estimator .
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