Water-Resources Data Network Evaluation for Monterey County, California, Phase 2: Northern and Coastal Areas of Monterey County By William E. Templin, Peter E. Smith, Myrna L DeBortoli, and Randall C. Schluter U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 95-4210 Prepared in cooperation with the MONTEREY COUNTY FLOOD CONTROL AND WATER CONSERVATION DISTRICT CO Sacramento, California 1996 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. For addtional information write to: Copies of this report can be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Earth Science Information Center Federal Building, Room W-2233 Open-File Report Section 2800 Cottage Way Box25286, Mail Stop 417 Sacramento, CA 95825 Denver Federal Center Denver, CO 80225 CONTENTS Abstract ..............................................................................................................^^ 1 Introduction.........................................................................................................._^ 2 Purpose and Scope....................................................................................................................................................... 2 Approach................................................................................................................................^ 2 Location of Study Areas.............................................................................................................................................. 4 Limitations....................................................................................................^^ 4 Acknowledgments............................................................................................................................................^ 4 Climate.............................................................................................................................................^ 4 Land Use.............................................................................................................................................^ 5 Water Use........................................,...,.................................................................................^ 10 Precipitation Networks........................................................................................................_^ 10 Precipitation-Quantity Networks................................................................................................................................. 10 Precipitation Conditions.................................................................................................................................... 10 Objectives ......................................................... 12 Methods Of Evaluation...................................................................................................................................... 12 Precipitation Maps............................................................................................................................................. 12 Description.................................................................^ 13 Factors Affecting Design................................................................................................................................... 16 Possible Modifications....................................................................................................................................... 17 Precipitation-Quality Networks................................................................................................................................... 18 Objectives...........................................................................................................^^ 18 Possible Problems.............................................................................................................................................. 18 Acid Rain................................................................................................................................................. 19 Pesticides................................................................................................................................................. 19 Design................................................................................................................^ 19 Surface-Water Networks..................................................................................................................................................^ 20 StreamflowNetworks.................................................................................................................................................. 20 StreamflowConditions...................................................................................................................................... 20 Objectives..................................................................................^^ 20 Methods of Evaluation....................................................................................................................................... 20 Criteria for Site Selection.................................................................................................................................. 21 Description of Streamflow-Gaging Stations...................................................................................................... 24 Possible Additional Streamflow-Gaging-Station Sites...................................................................................... 26 General Criteria for Site Selection and Justification of Proposed Sites ............................................................ 26 Reactivated Stations................................................................................................................................ 26 New Station Sites..................................................................................................................................... 27 Surface-Water-Quality Networks ................................................................................................................................ 28 Surface-Water-Quality Conditions .................................................................................................................... 28 Objectives................................................................^ 29 Methods of Evaluation....................................................................................................................................... 29 Station Location and Sampling Frequency........................................................................................................ 32 Description...................................................................^ 33 Stream-Reach Rating System............................................................................................................................ 33 Ground-Water Networks........................................................................................................_^ 34 Ground-Water Conditions............................................................................................................................................ 34 Geology............................................................................................................................................................. 34 Occurrence of Ground Water............................................................................................................................. 34 Ground-Water Flow........................................................................................................................................... 35 Contents III Flow Barriers.........................................................................................................^ 36 Water-Level Changes........................................................................................................................................ 36 Ground-Water-Quality Conditions.................................................................................................................... 37 Ground-Water-Level Networks................................................................................................................................... 37 Objectives....................................................^ 37 Methods of Evaluation...................................................................................................................................... 38 Well and Network Classification....................................................................................................................... 38 Well-Classification System..................................................................................................................... 38 Network-Classification System............................................................................................................... 39 Description..................................................................^ 39 Possible Additional Monitoring........................................................................................................................ 42 Ground-Water-Quality Networks...............................................................................................................................