CONTENTS ________ Page Preface ................................................................................................................................................ iii Report documentation page ................................................................................................................ iv List of stream and reservoir gaging stations, in downstream order for which records are published ........................................................................................................................................ viii List of lake gaging stations, in alphabetical order, for which records are published.......................... xiii List of ground-water wells, in alphanumeric order by county, for which records are published ......................................................................................................................................... xv List of discontinued surface-water discharge or stage-only stations .................................................. List of discontinued surface-water-quality stations ............................................................................ Introduction......................................................................................................................................... 1 Cooperation......................................................................................................................................... 2 Summary of hydrologic conditions .................................................................................................... 3 Precipitation .............................................................................................................................. 3 Surface water............................................................................................................................. 6 Ground water............................................................................................................................. 10 Downstream order and station number............................................................................................... 11 Numbering system for wells and miscellaneous sites ........................................................................ 11 Special networks and programs .......................................................................................................... 12 Explanation of stage- and water-discharge records ............................................................................ 14 Data collection and computation........................................................................................ 14 Data presentation................................................................................................................ 15 Station manuscript ..................................................................................................... 16 Peak discharge greater than base discharge ............................................................... 17 Data table of daily mean values................................................................................. 17 Statistics of monthly mean data................................................................................. 17 Summary statistics ..................................................................................................... 18 Hydrographs............................................................................................................... 20 Identifying estimated daily discharge................................................................................. 20 Accuracy of field data and computed results...................................................................... 20 Other data records available ............................................................................................... 21 Explanation of precipitation records......................................................................................... 21 Data collection and computation........................................................................................ 21 Data presentation................................................................................................................ 21 Explanation of water-quality records........................................................................................ 22 Collection and examination of data.................................................................................... 22 Water analysis..................................................................................................................... 22 Surface-water-quality records............................................................................................................. 23 Classification of records ..................................................................................................... 23 Accuracy of the records...................................................................................................... 23 Arrangement of records...................................................................................................... 24 On-site measurements and sample collection .................................................................... 24 Water temperature .............................................................................................................. 25 Sediment............................................................................................................................. 25 v vi CONTENTS ________ Page Laboratory measurements .................................................................................................. 25 Data presentation................................................................................................................ 26 Remark codes ..................................................................................................................... 27 Water-quality control data .................................................................................................. 27 Blank samples..................................................................................................................... 28 Reference samples.............................................................................................................. 29 Replicate samples...............................................................................................................29 Spike samples..................................................................................................................... 29 Explanation of lake level records.............................................................................................. 30 Data collection and computation........................................................................................ 30 Data presentation................................................................................................................ 30 Explanation of ground-water level records .............................................................................. 31 Site identification numbers................................................................................................. 31 Data collection and computation........................................................................................ 32 Data presentation................................................................................................................ 32 Water-level tables....................................................................................................... 34 Hydrographs............................................................................................................... 34 Ground-water-quality data ........................................................................................................ 34 Data collection and computation........................................................................................ 34 Laboratory measurements .................................................................................................. 35 Access to USGS water data ................................................................................................................ 35 Definition of terms.............................................................................................................................. 36 Publications on Techniques of Water-Resources Investigations of the U.S. Geological Survey........ 52 Selected references ............................................................................................................................. 57 Surface-water records ......................................................................................................................... 61 Discharge at miscellaneous sites......................................................................................................... 476 Lake records........................................................................................................................................ 478 Ground-water records ......................................................................................................................... 493 Miscellaneous project data ................................................................................................................. 581 Ground-water and surface-water levels in northern Lake County................................................... 582 Index ..................................................................................................................................................