2013-10-30_REVISION - M1977310 ‎(3)‎

• Permit No: M1977310
• IBM Index Class Name: REVISION
• Doc Date: 10/30/2013
• Doc Name: DRAINAGE DESIGN PLAN FOR THE JD6 MINE
• From: COTTER
• To: DRMS
• Type & Sequence: AM1
• Email Name: TC1
• Email Name: SJM
• Media Type: D
• Archive: No

JD -6 Mine - Drainage Design Plan i
TABLE OF CONTENTS
1. INTRODUCTION ....................................................................................................... ..............................1
1.1 Purpose .................................................................................................... ..............................1
1.2 Overview - Runoff Areas and Routing .................................................... ..............................1
1.3 Adjacent and Ancillary Facilities ............................................................ ............................... l
2. DESIGN CRITERIA & METHODOLOGY ............................................................... ..............................2
2.1 Design Storms .......................................................................................... ..............................2
2.2 Runoff Estimates ...................................................................................... ..............................2
2.2.1 Volume ....................................................................................... ..............................2
2.2.2 Peak Discharge ........................................................................... ..............................3
2.2.3 Computational Methods .............................................................. ..............................5
2.3 Structure Design ...................................................................................... ..............................5
2.3.1 Channel Capacity ........................................................................ ..............................5
2.3.2 Channel Stability ......................................................................... ..............................6
2.3.3 Culverts ....................................................................................... ..............................8
2.3.4 Retention Pond and Spillway ...................................................... ..............................8
2.3.5 Riprap / Granular Bedding / Gravel Mulch ................................ ..............................8
3. HYDROLOGIC CHARACTERISTICS OF SITE SOILS ......................................... .............................10
4. STORMWATER ROUTING ..................................................................................... .............................11
4.1
Sub -Basins Reporting to Upper, Middle, and Lower Diversion Structures .........................
11
4.2
Sub -Basin Intercepted by CR EE 19 ........................................................ .............................12
4.3
Sub -Basins Supplying Stormwater Run -on to the Site ........................... .............................14
4.4
Reach Definition ..................................................................................... .............................18
4.4.1 Upper Diversion Structure (UDS) ............................................. .............................18
4.4.2 Middle Diversion Structure (MDS) ........................................... .............................21
4.4.3 Lower Diversion Structure (LDS) ............................................. .............................22
4.5
Storage Structures ................................................................................... .............................24
4.5.1 Stormwater and Sediment Retention Pond ( SWRP) .................. .............................24
4.5.2 Planned Stormwater Retention Pond Expansion ....................... .............................26
4.5.3 Upstream Storage Ponds (USPs) ............................................... .............................28
4.6
Model Implementation of Stormwater Routing ...................................... .............................29
5. PEAK FLOW MODEL RESULTS ............................................................................ .............................31
5.1
Peak Flow Rates ...................................................................................... .............................31
5.2
Diversion Structure Capacity .................................................................. .............................35
5.3
Diversion Structure Stability .................................................................. .............................36
5.4
SWRP Capacity ...................................................................................... .............................39
5.5
Culvert Capacity ..................................................................................... .............................43
6. STRUCTURAL CONTROLS AND ADDITIONAL STORMWATER BMPS ........ .............................43
4148A.131028 WhetstoneAssotiates 4