A new streamflow-routing (SFR1) package to simulate stream-aquifer interaction with MODFLOW-2000 A NEWU.S. Geological STREAMFLOW-ROUTING Survey (SFR1) PACKAGE TO Open-FileSIMULATE Report 2004-1042STREAM-AQUIFER INTERACTION WITH125 yearsMODFLOW-2000 of science for America 1879-2004 U.S. Department of the Interior U. S Geological Survey U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 2004-1042 U.S. Department of the Interior U.S. Geological Survey Cover: Map showing simple stream network and cross section through representative stream segment illustrating some of the nomenclature used in the Streamflow-Routing Package. (See figs. 1 and 4 of this report and related discussions for more details.) A NEW STREAMFLOW-ROUTING (SFR1) PACKAGE TO SIMULATE STREAM-AQUIFER INTERACTION WITH MODFLOW-2000 A new streamflow-routing (SFR1) package to simulate stream- By David E. Prudic, Leonard F. Konikow, and Edward R. Banta aquifer interaction with MODFLOW-2000 U.S. GEOLOGICAL SURVEY OPEN-FILEBy REPORT David 2004-1042 E. Prudic, Leonard F. Konikow, and Edward R. Banta U.S. Geological Survey Open-File Report 2004-1042 Carson City, Nevada 2004 Carson City, Nevada 2004 U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, Secretary U.S. GEOLOGICAL SURVEY CHARLES G. GROAT, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government For additional information Copies of this report can be contact: purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Information Services 333 West Nye Lane, Room 203 Building 810 Carson City, NV 89706–0866 Box 25286, Federal Center Denver, CO 80225–0286 email: [email protected] http://nevada.usgs.gov iii CONTENTS Abstract.................................................................................................................................................................................. 1 Introduction............................................................................................................................................................................ 1 Purpose and Scope ..................................................................................................................................................... 2 Acknowledgments...................................................................................................................................................... 2 Approach to Streamflow Routing ......................................................................................................................................... 2 Ordering and Numbering of Streams ......................................................................................................................... 2 Stream-Aquifer Connection ....................................................................................................................................... 4 Stream Water Budgets................................................................................................................................................ 6 Computing Stream Depth........................................................................................................................................... 6 Diverting Streamflow ................................................................................................................................................. 9 Stream-Lake Interconnections ................................................................................................................................... 9 Solute Transport ......................................................................................................................................................... 10 Assumptions and Limitations..................................................................................................................................... 12 Test Simulations..................................................................................................................................................................... 13 Test 1: Stream-Aquifer Interaction............................................................................................................................ 13 Test 2: Stream-Lake Interaction with Solute Transport ............................................................................................ 24 Implementation of SFR1 Package with MODFLOW-2000................................................................................................... 29 Integration of MODFLOW-GWT with SFR1 and LAK3 Packages...................................................................................... 30 Summary................................................................................................................................................................................ 34 References Cited.................................................................................................................................................................... 35 Appendix 1—Data Input Instructions for Streamflow-Routing (SFR1) Package ................................................................ 39 Appendix 2—Selected Input Data and Printed Results for Test Simulation 1 ...................................................................... 55 Appendix 3—Selected Input Data and Printed Results for Test Simulation 2 ...................................................................... 77 FIGURES 1. Diagram showing simple stream network having three segments and six reaches in a finite-difference model grid consisting of three rows and three columns.................................................................................................... 3 2. Diagrams showing (A) multiple connected reaches in a model cell, (B) two parallel reaches in a model cell, and (C) only one reach connected to a single model cell even if stream is wider than the cell............................. 4 3. Diagram showing example of a segment-numbering scheme in relation to direction of flow and a finite-difference model grid ................................................................................................................................... 5 4. Diagram illustrating an eight-point cross section used to compute depth, width, and wetted perimeter for a stream segment....................................................................................................................................................... 8 5. Diagram illustrating bisection-secant method used to determine depth of stream from Manning’s equation assuming an eight-point cross section.................................................................................................................... 8 6. Map showing hypothetical basin-fill aquifer with model grid, land-surface contours, and stream segment and reach numbering scheme for test simulation 1................................................................................................ 14 7. Model grid showing elevation of top of consolidated rocks beneath basin-fill aquifer and distribution of hydraulic conductivity and specific yield of the basin-fill aquifer used in test simulation 1................................. 15 8. Model grid showing steady-state simulation of water-table contours, distribution of ground-water evapotranspiration, and locations of perennial-flow reaches used as initial conditions for the transient part of test simulation 1.......................................................................................................................................... 16 9. Graphs showing stream cross sections used in computing stream depth for segments 7 and 8 in test simulation 1............................................................................................................................................................ 18 iv 10. Model grid showing simulated water-table contours, distribution of ground-water evapotranspiration, and locations of perennial-flow reaches after 50 years of pumping for test simulation 1 ............................................ 20 11. Graphs comparing changes in stream depth, width, and flow in last reach of selected stream segments during a 50-year pumping period in test simulation 1 followed by a 50-year recovery period ............................. 22 12. Graphs showing changes in streambed conductance in last reach of selected stream segments during a 50-year pumping period in test simulation 1 followed by a 50-year recovery period......................................... 25 13. Diagram showing finite-difference model grid of layer 1, boundary conditions, and locations of lakes and streams used in test simulation 2............................................................................................................................ 26 14. Diagrams showing contours of simulated steady-state heads in (A) layer 1 and (B) layer 2 for test simulation 2............................................................................................................................................................ 28 15. Diagram showing distribution of vertical flow velocity between layers 1 and 2 for steady-state conditions in test simulation 2 ..................................................................................................................................................... 29 16. Graphs showing changes in simulated boron concentrations in lake