~ ~ U. S. Army Corps Interstate Commission of Engineers on the Potomac River Basin Planning Assistance to States Jennings Randolph Lake Scoping Study Phase II Report APRIL 2020 Prepared by: U.S. Army Corps of Engineers, Baltimore District Laura Felter and Julia Fritz and Interstate Commission on the Potomac River Basin Cherie Schultz, Claire Buchanan, and Gordon Michael Selckmann Contents Executive Summary ....................................................................................................................................... 1 1 Introduction .......................................................................................................................................... 3 1.1 Purpose ......................................................................................................................................... 3 1.2 Study Authority ............................................................................................................................. 3 1.3 Congressional Authorizations and Project Objectives .................................................................. 3 1.4 Study Area Management .............................................................................................................. 4 2 Scoping Studies ..................................................................................................................................... 7 3 Watershed Conditions Analysis ............................................................................................................ 7 3.1 Flood Management ....................................................................................................................... 7 3.1.1 Management Goals and Objectives ...................................................................................... 8 3.1.2 Current Relevance ................................................................................................................. 8 3.1.3 Future Flood Control ........................................................................................................... 10 3.2 Water Quality Control ................................................................................................................. 10 3.2.1 Management Goals and Objectives .................................................................................... 11 3.2.2 Current Relevance ............................................................................................................... 12 3.2.2.1 Improve pH ..................................................................................................................... 12 3.2.2.2 Manage Temperature ..................................................................................................... 13 3.2.2.3 Dilute downstream wastewater discharges ................................................................... 14 3.2.2.4 Maintain a healthy downstream aquatic habitat ........................................................... 15 3.2.3 Other Water Quality Conditions ......................................................................................... 16 3.2.3.1 Dissolved Oxygen ............................................................................................................ 16 3.2.3.2 Specific Conductivity and Total Dissolved Solids ............................................................ 17 3.2.3.3 Turbidity and Total Suspended Solids ............................................................................. 17 3.2.4 Current Conditions for Aquatic Life .................................................................................... 18 3.2.4.1 Physical Habitat and Biological Monitoring in the NBPR Mainstem ............................... 18 3.2.4.2 Aquatic Life Zones ........................................................................................................... 19 3.3 Domestic/Industrial Water Supply .............................................................................................. 19 3.3.1 Management Goal and Objectives ...................................................................................... 20 3.3.2 Current Relevance ............................................................................................................... 21 3.3.2.1 Climate Change and Rising Demands .............................................................................. 21 3.3.2.2 Preliminary Investigation ................................................................................................ 22 3.3.3 Potential Use of Drought Planning and Management Tools .............................................. 22 3.3.3.1 Drought Contingency Plans ............................................................................................. 22 3.3.3.2 Deviation Plans ................................................................................................................ 23 ii 3.3.3.3 Water Accounting Procedures ........................................................................................ 23 3.4 Recreation ................................................................................................................................... 24 3.4.1 Management Goal and Objectives ...................................................................................... 24 3.4.2 Current Relevance ............................................................................................................... 24 3.4.2.1 Boating and Whitewater ................................................................................................. 25 3.4.2.2 Fishery ............................................................................................................................. 26 3.4.3 Future Enhancements ......................................................................................................... 26 3.5 Summary of Watershed Conditions Findings .............................................................................. 27 4 Quantitative Support Tools ................................................................................................................. 29 4.1 Existing Modeling Tools .............................................................................................................. 29 4.1.1 Baltimore District Tools ....................................................................................................... 29 4.1.2 ICPRB Tools ......................................................................................................................... 31 4.1.2.1 CO-OP Operational Tools ................................................................................................ 31 4.1.2.2 CO-OP Planning Model .................................................................................................... 32 4.1.3 Collaborative Tools.............................................................................................................. 32 4.2 Regulation of Downstream Temperature ................................................................................... 33 4.2.1 Temperature Model Options .............................................................................................. 33 4.2.1.1 Statistical models for temperature prediction ............................................................... 33 4.2.1.2 Deterministic models for temperature prediction ......................................................... 34 4.2.1.3 Temperature modeling capabilities in HEC software packages ...................................... 35 4.2.2 Data Support ....................................................................................................................... 35 5 Summary of Findings with Respect to JRL Dam Operations ............................................................... 36 5.1 Flood ........................................................................................................................................... 36 5.2 Water Quality .............................................................................................................................. 36 5.3 Instream Habitat ......................................................................................................................... 37 5.4 Water Supply ............................................................................................................................... 37 6 Recommendations .............................................................................................................................. 37 7 References .......................................................................................................................................... 38 iii Abbreviations µS/cm Micro Siemens per centimeter ac-ft Acre-feet AMD Acid mine drainage AVF Artificially varied flow BG Billion gallons CE-QUAL-W2 two-dimensional hydrodynamic and surface water quality model cfs Cubic feet per second CMIP5 Coupled Model Inter-Comparison Project Phase 5 CO-OP ICPRB’s Section for Cooperative Operations on the Potomac CWMS Corps Water Management System DCP Drought Contingency Plan DO Dissolved oxygen ER Engineering Regulations FEWS Flood Early Warning System FT Feet GSFLOW USGS groundwater-surface water modeling package HEC-FIA USACE’s Hydrologic Engineering Center Flood Impact Analysis model HEC-HMS USACE’s Hydrologic Engineering Center Hydrologic Modeling System HEC-RAS USACE’s Hydrologic Engineering Center River Analysis System flow routing model HEC-ResSim USACE’s