2012-02-28_REVISION - M1980244 (6)

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History Recreatio Buffer Bndy. Emergency Spillway✓ EMP -022 3 Plan View 1" =100 ft (DSize) Pond a receives Runoff from South Tributary North tributaryis �c bypassed around x structure Spillway Riser between Ponds i, Pond b Receives Runoff from South side lN9 i i Minimal Area outside Historic - Recreation Buffer'- - 9850 Historic 9g Recreation � 9900 rest 1 t ' Buffer Bnd . - 1nom From Basin PG Al C2) EMP -021 Plan View 1 " =100 ft (DSize) Total Buffer 0 f Encroachment Pond EMP_ -09a 7058 Cut 1.2 Acres 6506 fill Net Shortage 552 Capacity 2.8 AF 923 / 0 �9 ✓ ^j - Lower South Ditc Flow from Basins PG -B1 and PG -C1 Historic i Pond EMP -09b Recreation 2447clut y. � 2993 fill Buffer Bndy. Net Excess 543 Capacity 1.6AF ow from Basin PG -E1 Pond EMP 09 ° 9317 Cut Natural Channel Net Excess 6476 Tributary Flow Capacity 3.9 AF ZA 0 - — EMP -009 Four Ponds, a, b, c, and d Plan View 1 " =100 ft (DSize) 10120 10080 10040 10000 996 PROFILED, At.5 9920 - 9880 North Ditch into EMP -09b North Ditch is Primarily an interceptor, not a conveyance channel .. Follows Old - bandonedgrade South Ditch into EMP -09a Grade Ditch on Inside of Existing Roadway 10120 10080 10040 10000 9960 9920 9880 Note: All but Pond 009a will be eliminated in 2017 and must be reconstructed in 2018 when backfill begins k1�j �9 1419 Pond EMP_ -09 d 4100 Cut 1500 fill Net Excess 2600 Capacity 1.7AF Profile F, Sht. 5 Profile E 9840 -� 3 14% tYp) At. 5 � �� - PROFILE C Sht. S 9840 980Qfl r er 35 �/ 3 52% (Avg) 10080 9800 -., it) Q0 0 b o co o rr o I-, (Z) co N d N M to 10040 10000 DATUM 1s-LEV 976t ° _ o a - -ar .' °o °0 - o- . - `ai °cam —°' -- °v' -- 6 -- dam- - -L- <r <r L6 c6 ri co c`�o - -- „k -- 9 50. 00 0 0 0 0 ao ai TmT ao vJ Qi rawo Co ai arto ()o vJ m cTow vJ CO m ao rn rn a) Qi rtrnT vJ Q; N M n n R n eNa eoa �� 9920 9900.00 0 0 0 0 0 0 0 0 0 o rn 0+00(o) rn M 00, rn 0 0 0 0 0 0 0 15 +00 10 +00 5 +00 0 +00 5 +00 10 +00 15 +00 20 +00 25 +00 30 +00 35 +00 0+00 5 +00 PROFILES 6 C & D - Lower North Ditch Cross Country to EMP -09 and Lower South Ditch along Access Road to EMP -009 Profile View Profile View 1" =500 ft (DSize) 1 " =500 ft (DSize) EMP -21 Note: All but Pond 009a will be eliminated in 2017 and must be reconstructed in 2018 when backfill begins k1�j �9 1419 Pond EMP_ -09 d 4100 Cut 1500 fill Net Excess 2600 Capacity 1.7AF Profile F, Sht. 5 Profile E Notes and General Specifications: 1. Ditches along access roads should generally be triangular cross - section to facilitate cleaning with a road - grader. The dimensions of ditches are listed on Sheet 5, along with the expected armoring requirements (3 "Riprap, 6" Riprap or vegetated channels). The freeboard is calculated to include a minimum of 6- inches at the 100 year calculated discharge plus the velocity head depth. 2. EMP' Ponds and their embankments are intended to be water tight because of their proximity to high walls of the mining areas and to the Historic Recreation Buffer Zone. Accordingly, they shall be constructed to conform to the following general specifications: a. Remove soils within the footprint of the pond area down to suitable non - organic soils with no less than 15-20% fines ( <200 mesh). Proof roll the footprint and compact as needed to achieve a target density of no less than 90% in the basin and no less than 95% Std. Proctor in the embankmant. b. Select soils for the embankment that have at least 15% fines. Place and compact the embankment soils in 8 -inch maximum loose layers and compact to at least 95% Std. Proctor density. c. Maximum slope of embankment shall be 2 :1. Maximum slope inside sediment basin shall be 1.751. Maximutrn slope of reseeded areas shall be 3:1. 3. An emergency spillway shall be constructed at each pond with a finished invert elevation approximately 2.0 feet lower than the crest and abase width of 6.0 feet. The spillway shall be armored with 6" angular norap place on 6- inches of sandy - gravel bedding and a layer of Mirifi drain fabric. At. 5 I 10120 10120 Area Graded 35 10320 10280 3 52% (Avg) 10080 to serve -., 10080 10040O_r \ 10240 10040 10000 8 >6, 50/0 0.17% _ 10000 996 �0 „k 9960 r� o M o 0 0 0 o rn' o DATUM F'Z,E V o rn 000 °m Q; N M o - -�� e°a eNa eoa �� 9920 9900.00 0 0 0 0 0 0 0 0 0 o rn 0+00(o) rn M 00, rn 0 0 0 0 0 0 0 30 +00 25 +00 20 +00 15 +00 10 +00 5 +00 0+00 5 +00 10 +00 PROFILES E & F 5 - Upper South and North Ditches to EMP -21, to replace EMP -08a in 2014 Profile View 1 " =500 ft (DSize) to EMP08a Profile View 1" =500 ft (DSize) Notes and General Specifications: 1. Ditches along access roads should generally be triangular cross - section to facilitate cleaning with a road - grader. The dimensions of ditches are listed on Sheet 5, along with the expected armoring requirements (3 "Riprap, 6" Riprap or vegetated channels). The freeboard is calculated to include a minimum of 6- inches at the 100 year calculated discharge plus the velocity head depth. 2. EMP' Ponds and their embankments are intended to be water tight because of their proximity to high walls of the mining areas and to the Historic Recreation Buffer Zone. Accordingly, they shall be constructed to conform to the following general specifications: a. Remove soils within the footprint of the pond area down to suitable non - organic soils with no less than 15-20% fines ( <200 mesh). Proof roll the footprint and compact as needed to achieve a target density of no less than 90% in the basin and no less than 95% Std. Proctor in the embankmant. b. Select soils for the embankment that have at least 15% fines. Place and compact the embankment soils in 8 -inch maximum loose layers and compact to at least 95% Std. Proctor density. c. Maximum slope of embankment shall be 2 :1. Maximum slope inside sediment basin shall be 1.751. Maximutrn slope of reseeded areas shall be 3:1. 3. An emergency spillway shall be constructed at each pond with a finished invert elevation approximately 2.0 feet lower than the crest and abase width of 6.0 feet. The spillway shall be armored with 6" angular norap place on 6- inches of sandy - gravel bedding and a layer of Mirifi drain fabric. EMP -08a Low Area Graded 10320 10280 3 52% (Avg) to serve as DetePond \ 10240 ,,, - Open Ditch -� 10200 Graded on Existing „k 10160 r� o Roadways o 0 0 0 o rn' o DATUM L;LEV rn (0� � ( Q; N ai o 0 ang �� M ,I 10100.00 � 0 N 0 N N N N N N N 0 0 N 000 (NZ) 0 0 0 0 0 0 0 0 0 +00 5 +00 10 +00 15 +00 20 +00 25 +00 30 +00 35 +00 40 +00 45 +00 4 PROFILE G- Poverty Gulch /Schist Island - Upper Ditch to EMP08a Profile View 1" =500 ft (DSize) Notes and General Specifications: 1. Ditches along access roads should generally be triangular cross - section to facilitate cleaning with a road - grader. The dimensions of ditches are listed on Sheet 5, along with the expected armoring requirements (3 "Riprap, 6" Riprap or vegetated channels). The freeboard is calculated to include a minimum of 6- inches at the 100 year calculated discharge plus the velocity head depth. 2. EMP' Ponds and their embankments are intended to be water tight because of their proximity to high walls of the mining areas and to the Historic Recreation Buffer Zone. Accordingly, they shall be constructed to conform to the following general specifications: a. Remove soils within the footprint of the pond area down to suitable non - organic soils with no less than 15-20% fines ( <200 mesh). Proof roll the footprint and compact as needed to achieve a target density of no less than 90% in the basin and no less than 95% Std. Proctor in the embankmant. b. Select soils for the embankment that have at least 15% fines. Place and compact the embankment soils in 8 -inch maximum loose layers and compact to at least 95% Std. Proctor density. c. Maximum slope of embankment shall be 2 :1. Maximum slope inside sediment basin shall be 1.751. Maximutrn slope of reseeded areas shall be 3:1. 3. An emergency spillway shall be constructed at each pond with a finished invert elevation approximately 2.0 feet lower than the crest and abase width of 6.0 feet. The spillway shall be armored with 6" angular norap place on 6- inches of sandy - gravel bedding and a layer of Mirifi drain fabric.