Story Mill Wetland Delineation UPPER BLACKFOOT MINING COMPLEX 50% Preliminary Restoration Design Lincoln, Montana Submitted To: State of Montana, Department of Justice Natural Resource Damage Program PO Box 201425 Helena, Montana 59620 Prepared By: River Design Group, Inc. 5098 Highway 93 South Whitefish, Montana 59937 Geum Environmental Consulting, Inc. 307 State Street Hamilton, Montana 59840 March 2014 Preliminary Design Report This page left intentionally blank -i- Preliminary Design Report Table of Contents 1 Introduction .................................................................................................... 1 1.1 Project Background .......................................................................................................... 3 1.2 Evaluation of Alternatives ................................................................................................ 5 1.2.1 Description of Alternatives ....................................................................................... 5 1.2.2 Evaluation of Alternatives ......................................................................................... 5 1.2.3 Evaluation Summary ................................................................................................. 8 1.3 Project Vision, Goals and Objectives ................................................................................ 9 1.4 Restoration Strategies .................................................................................................... 10 1.5 Project Area Description ................................................................................................ 11 1.5.1 Reach Delineations ................................................................................................. 12 1.6 Watershed Overview ...................................................................................................... 14 1.6.1 Climate .................................................................................................................... 14 1.6.2 Vegetation ............................................................................................................... 15 1.6.3 Geology ................................................................................................................... 16 1.6.4 Soils ......................................................................................................................... 17 1.6.5 Hydrology and Water Quality ................................................................................. 18 1.6.6 Watershed Processes .............................................................................................. 18 1.6.7 Fisheries and Aquatic Habitat ................................................................................. 21 2 Design Investigations .................................................................................... 25 2.1 Channel Forming Discharge and Flood Frequency Analysis .......................................... 25 2.1.1 Channel Forming Discharge .................................................................................... 25 2.1.2 Flood Frequency Analysis........................................................................................ 28 2.2 Channel Morphology ...................................................................................................... 31 2.2.1 Methods .................................................................................................................. 32 2.2.2 Anaconda Creek: B3 / B4 Stream Type ................................................................... 35 2.2.3 Snowbank Creek: C4b Stream Type ........................................................................ 36 2.2.4 Arrastra Creek: C4 Stream Type ............................................................................. 37 2.2.5 Copper Creek: C3 / C4 Stream Type ....................................................................... 38 2.3 Hydraulics ....................................................................................................................... 38 2.3.1 Methods .................................................................................................................. 39 2.3.2 Results ..................................................................................................................... 39 -ii- Preliminary Design Report 2.4 Tie-In Analysis ................................................................................................................. 47 2.4.1 Methods .................................................................................................................. 47 2.4.2 Results ..................................................................................................................... 49 2.5 Vegetation Analysis ........................................................................................................ 50 2.5.1 Methods .................................................................................................................. 50 2.5.2 Existing Vegetation Communities ........................................................................... 51 3 Design Criteria ............................................................................................... 61 3.1 Introduction.................................................................................................................... 61 3.2 Restoration Constraints ................................................................................................. 61 3.2.1 Reach 1 Mining Infrastructure ................................................................................ 61 3.2.2 Reach 3 Adit Drains, Temporary Construction Haul Road, and Diversion .............. 61 3.2.3 Reach 4 Water Treatment Plant ............................................................................. 61 3.2.4 Cultural Resources .................................................................................................. 62 3.3 Geomorphic Design Criteria ........................................................................................... 62 3.3.1 Design Flows ........................................................................................................... 62 3.3.2 Channel Cross-Section Dimensions and Planform Design Criteria ......................... 63 3.4 Channel Hydraulic Design Criteria .................................................................................. 68 3.5 Floodplain Design Criteria .............................................................................................. 71 3.5.1 Introduction ............................................................................................................ 71 3.5.2 Floodplain Features ................................................................................................ 71 3.6 Streambank Design Criteria ........................................................................................... 73 3.6.1 Introduction ............................................................................................................ 73 3.6.2 Streambank Treatments ......................................................................................... 74 3.7 Aquatic Habitat Design Criteria ...................................................................................... 77 3.7.1 Aquatic Habitat Design Criteria .............................................................................. 78 3.8 Vegetation Design Criteria ............................................................................................. 79 3.8.1 Vegetation Design Criteria ...................................................................................... 80 3.8.2 Vegetation Cover Type Descriptions....................................................................... 88 4 Preliminary Restoration Design by Reach ...................................................... 98 4.1 Reach 1 Mike Horse Creek ............................................................................................. 98 4.1.1 Introduction ............................................................................................................ 98 4.1.2 Restoration Strategies in Reach 1A......................................................................... 98 4.1.3 Restoration Strategies in Reach 1B ....................................................................... 100 4.1.4 Restoration Strategies in Reach 1C ....................................................................... 100 -iii- Preliminary Design Report 4.2 Reach 2 Upper Beartrap Creek ..................................................................................... 101 4.2.1 Introduction .......................................................................................................... 101 4.2.2 Restoration Strategies .......................................................................................... 101 4.3 Reach 3 Lower Beartrap Creek ..................................................................................... 104 4.3.1 Introduction .......................................................................................................... 104 4.3.2 Restoration Strategies .......................................................................................... 104 4.4 Reach 4 Upper Blackfoot River ..................................................................................... 107 4.4.1 Introduction .........................................................................................................