2014-10-10_PERMIT FILE - C1996083 ‎(2)‎

• Permit No: C1996083
• IBM Index Class Name: Permit File
• Doc Date: 10/10/2014
• Doc Name: WWE Subsidence Impact Evaluation - PR14 Spruce Stomp
• Section_Exhibit Name: Volume IIIB Exhibit 23 Spruce Stomp Subsidence Evaluation
• Media Type: D
• Archive: No

TABLE OF CONTENTS
Page
1.0 REPORT PURPOSE ......................................................................... ..............................1
2.0 SUMMARY OF FINDINGS ................................................................
..............................1
3.0 INVESTIGATION APPROACH ......................................................... ..............................2
4.0 BACKGROUND AND PHYSICAL SETTING .................................... ..............................3
4.1 West Fork Terror Creek Watershed ..................................................... ...............................
3
4.1.1
Geographic Setting ............................................................ ...............................
3
4.1.2
Topography and Land Use ................................................ ...............................
3
4.1.3
Geology /Geologic Features ................................................ ..............................4
4.1.4
Soils ................................................................................... ...............................
4
4.1.5
Vegetation Communities / Ecosystems ............................... ...............................
5
4.1.6
Climate ................................................................................ ..............................5
4.1.7
Water Bodies (Reservoirs, Creeks, Ditches and Springs) . ...............................
6
4.2 West Fork Terror Creek in Vicinity of Potential Project Area ............... ...............................
6
4.2.1
Physical Characteristics ...................................................... ..............................
7
I.
Stream Flows ...................................................................... ..............................7
II.
Channel Profile, Slope, Sinuosity, Bed and Bank Composition, etc .................
7
III.
Typical Channel Cross Sections ........................................ ...............................
8
IV.
Physical Habitat Description .............................................. ............................... 8
4.2.2
Water Quality (Designated Uses, Standards and Baseline Quality) ................ 9
4.2.3
Biological ............................................................................ .............................11
4.2.4
Groundwater – Surface Water Interactions ......................... .............................14
4.3 Existing
Anthropogenic Influences to West Fork Terror Creek ............ .............................14
4.3.1
Utility Lines (Including Above- and Below- Ground Power Lines, Aqueducts
andWater Ditches) .............................................................................. .............................14
4.3.2
Roads and Railroads ......................................................... .............................14
4.3.3
Mines ................................................................................. .............................15
4.3.4
Water Diversion and Storage Facilities ............................. .............................15
4.3.5
Agriculture (Including Farming, Ranching and Silviculture ) ............................15
4.3.6
Other .................................................................................. .............................16
5.0 POTENTIAL MINING ACTIVITIES, ANTICIPATED SUBSIDENCE AND PROJECT
EFFECTS......................................................................................... .............................16
5.1 Subsidence Evaluation of the Terror Creek Mining Area ..................... .............................17
5.2 Characterization of Surface Impacts .................................................... .............................17
5.2.1 Pre- and Post- Project Channel Profile .............................. .............................18
5.2.2 Characterization of Pre- and Post- Project Area Slopes ... .............................18
5.2.3 Characterization of Surface Fractures ............................... .............................19
5.2.4 Characterization of Pre- and Post - Mining Geologic Hazards ......................... 20
5.3 Reasonableness Checking— Comparison to Nearby Mines ................ .............................21
6.0 POTENTIAL IMPACTS TO WEST FORK TERROR CREEK'S ASSOCIATED
AQUATICLIFE ................................................................................ .............................21
6.1 Impacts Resulting from Channel Profile Changes ............................... .............................22
6.1.1 Changes in Fish Habitat .................................................. ............................... 22
6.1.2 Changes in Stream Flow ................................................. ............................... 22
6.1.3 Changes in Water Quality ................................................ ............................... 22
6.1.4 Potential for New Fish Travel Barriers or Conduits ......... ............................... 23