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Home My WebLink AboutSW4240102_Plansheet - Misc. Detail_20241018 -' - SPECIFICATIONS FOR DETENTION BASIN M C)- -- - �N W- - _ - W - 1. AREAS UNDER THE EMBANKMENT AND ANY STRUCTURAL WORKS SHALL BE CLEARED, GRUBBED AND STRIPPED OF TOPSOIL, ROOTS OR OTHER OBJECTIONABLE MATERIAL. UNLESS Z N _ - _ - _ - W W W CD W _ _ - - - - - OTHERWISE NOTED,TO FACILITATE CLEAN OUT AND RESTORATION,THE BASIN AREA WILL BE CLEARED OF ALL BRUSH AND EXCESS TREES. W Z - �1•. - • _ _ - - - - - - - - - - 2. THE SUITABILITY AND ACCEPTABILITY OF ALL FILL MATERIAL WILL BE DETERMINED BY REGULAR PERIODIC SOIL ANALYSIS AND COMPACTION TEST WHICH SHALL BE MADE BY THE OWNER'S Of 0 GEOTECHNICAL ENGINEER. TEST FOR SOIL ANALYSIS, MOISTURE CONTENT,AND COMPACTION ARE TO BE CONDUCTED IN ACCORDANCE WITH THE LATEST ASTM STANDARDS. COMPACTION V [If SHALL NOT BE LESS THAN 98% OF THE MAXIMUM DENSITY FOR THE GIVEN EMBANKMENT MATERIAL AS DETERMINED BY THE ASTM D-698 AND NOT ALLOW SEEPAGE THROUGH THE DAM. U) Q CONTROLLED FILL FOR EMBANKMENT CONSTRUCTION SHOULD HAVE AT LEAST 12% FINES BY WEIGHT. SOILS WITH UNIFIED SOIL CLASSIFICATION SYSTEM GROUP SYMBOLS OF SM, SC, AND - z C) 0 - - - - - ML ARE SUITABLE FOR USE AS CONTROLLED FILL. SOILS WITH USCS GROUP SYMBOL OF CL WHICH MEET THE RESTRICTIONS FOR LIQUID LIMIT AND PLASTICITY INDEX ARE ALSO SUITABLE Q ❑ � 0 - - - - - A v v FOR USE, UNLESS OTHERWISE INSTRUCTED BY THE GEOTECHNICAL ENGINEER j < ()f 0 _ - - 3. THE FILL SHALL BE CONSTRUCTED IN 6" LIFTS AND SHALL BE CONTINUOUS OVER THE ENTIRE LENGTH OF THE FILL SO THAT SMOOTH HORIZONTAL PLANES ARE NOT BUILT INTO THE FILL J t9 - a - - - - - STRUCTURE.SMOOTH HORIZONTAL PLANES SHALL BE AVOIDED BY SCARIFYING OR THE USE OF SHEEPSFOOT ROLLERS. (n Z N /• � \� -D 1 /- - 4. THE EMBANKMENT SHALL BE CONSTRUCTED TO A MINIMUM ELEVATION 5%HIGHER THAN THE DESIGN HEIGHT TO ALLOW FOR SETTLEMENT WHEN MECHANICAL COMPACTORS ARE USED. Z_ W m � 5. EMBANKMENT CONSTRUCTION SHALL BE MONITORED AND COMPACTION TESTED BY ON-SITE GEOTECHNICAL ENGINEER. ON-SITE SOILS MAY BE SUITABLE FOR POND BOTTOM AND -0 O I- Z co /' t9 \ I I / _ • - - - - - - • _ . - • - -1 - EMBANKMENT FILLS.THE CONTRACTOR MAY BE REQUIRED TO OBTAIN SUITABLE SOIL FROM ON-SITE IN AREAS OUTSIDE OF THE POND LIMITS. THE OWNERS GEOTECHNICAL ENGINEER WILL (1) WLLI c`i APPROVE SOILS FOR SUITABLITY OF POND AND DAM EMBANKMENT CONSTRUCTION.COMPACTED MATERIAL SHALL HAVE A MAXIMUM PERMEABILITY OF 0.00001 CM/SEC _ > N z o X Q / 'S / / 1• 6. IF REQUIRED PERMEABILTY LIMITS CANNOT BE MET WITH ON-SITE SOILS, THE OWNER, ENGINEER AND GEOTECHNICAL ENGINEER SHALL DETERMINE A SUITABLE METHOD TO MEET U I d W PERMEABILITY REQUIREMENTS. THIS MAY INCLUDE IMPORT OF SOIL MATERIAL FROM OFF-SITE, AMMENDMENT WITH BENTONITE OR INSTALLATION OF IMPERMEABLE LINERS. THE +i 7& / - \ CONTRACTORS BASE BID SHALL ASSUME THAT ON-SITE SOILS CAN BE UTILIZED. IMPORTED MATERIAL, SOIL AMENDMENTS AND IMPERMEABLE LINERS WILL BE CONSIDERED ADDITIONAL COST. /- I I - • - - - - / \ + '9 7. ALL AREAS OF THE BOTTOM,SIDESLOPES AND EMBANKMENTS OF THE POND SHALL HAVE 4"OF TOPSOIL AND COMPACTED IN A MANNER TO ENSURE VEGETATIVE GROWTH. 7 . - - 1 •> 8. IF THE POND IS CONSTRUCTED IN THE SUMMER OR EARLY FALL MONTHS, IT IS ADVISED TO INSTALL SOD ON THE BOTTOM, SIDE SLOPES, AND DAM EMBANKMENTS TO ENSURE VEGETATIVE - - - - - - - - - - COVERAGE AND STABILIZATION. IT IS ADVISED T INSTALL BMP/SCM PLANTINGS IN THE FALL _ DETAILED SEQUENCE OF CONVERSION OF SEDIMENT BASIN NO.1 TO THE PERMANENT WET DETENTION BASIN 1. CONTINUE TO MAINTAIN EROSION CONTROL MEASURES UNTIL VEGETATIVE COVER HAS BEEN ESTABLISHED OVER ALL DISTURBED AREAS AND SITE HAS BEEN STABILIZED. BEGIN i�� CONVERSION TO WET DETENTION BASIN ONLY AFTER FINAL INSPECTION AND APPROVAL BY INSPECTOR. IF VEGETATION HAS NOT BEEN PREVIOUSLY ESTABLISHED ON POND SLOPES, ;� CSRQ� - - - - / PROVIDE STABILIZATION WITH SOD. 2. CONVERSION TO BASIN SHOULD BE SCHEDULED WHEN A PERIOD OF DRIER WEATHER IS PREDICTED. BEGIN REMOVAL OF ACCUMULATED SEDIMENT FROM BOTTOM OF BASIN. EXCAVATED MATERIAL TO BE WASTED OFF-SITE IN AN PERMITTED AND APPROVED LOCATION.SKIMMER MAY BE TEMPORARILY REMOVED DURING THE DAY TO ALLOW WORK BUT SHALL BE REPLACED AT z AL 7�-j THE END OF EACH WORKING DAY IN THE EVENT OF RAIN. REMOVE SEDIMENT BAFFLES. COMPLETELY REMOVE SEDIMENT TO ESTABLISH PROPOSED CONTOURS AND VOLUMES. GRADE 197 �O FOREBAY BERMS IF NOT PREVIOUSLY GRADED. Q� d 3. IF RAIN IS FORECAST DURING CONVERSION REINSTALL SKIMMER. REMOVE ADDITIONAL ACCUMULATED SEDIMENT AS NEEDED. C��S 4. REGRADE AND/OR COMPLETE FINE GRADING OF BASIN AS NECESSARY TO ENSURE FINAL PERMANENT WET DETENTION POND AND FOREBAY VOLUMES, ELEVATIONS AND SPECIFICATIONS ARE MET. 5. BEGIN GEOTECHNICAL TESTING TO ENSURE SOILS IN THE POND(BOTTOM AND EMBANKEMENT SLOPES)WILL MEET MAXIMUM INFILTRATION RATE REQUIRED TO ENSURE PERMANENT POOL ELEVATION WILL HOLD. 6. N THE EVENT THAT GEOTECHNICAL TESTING RESULTS IN FAILURE TO MAINTAIN PERMANENT POOL ELEVATION, IMMEDIATELY CEASE CONVERSION OPERATIONS AND CONTACT ENGINEER OF `\\ \------- -------------------------- 1\\ RECORD TO INFORM THAT DESIGN WILL NEED TO BE REVISED TO ACCOMMODATE THE CURRENT CONDITIONS. ENGINEER OF RECORD MUST SUBMIT REVISED DESIGN TO THE CITY OF ------------------------- ` \ WINSTON-SALEM STORMWATER ENGINEER FOR HIS APPROVAL. ENGINEER OF RECORD SHALL NOTIFY CONTRACTOR TO IMPLEMENT THE REVISED DESIGN SPECIFICATIONS AND PROVIDE A 1 COPY OF REVISED AND APPROVED PLAN. I �. 1 7. COMPLETE FINAL REMOVAL OF TEMPORARY SKIMMER ASSEMBLY AND STABILIZE POND SIDE SLOPES ABOVE PERMANENT POOL ELEVATIONS AND ADJACENT ARES IN ACCORDANCE WITH PERMANENT SEEDING SPECIFICATIONS. INSTALL PERMANENT POND BOTTOM DRAIN AND GATE VALVE. 8. CLOSE GATE VALVE ON RISER AND CHECK INTEGRITY OF OVERALL RISER STRUCTURE TO ENSURE NO LEAKAGE OCCURS. POND CAN NOW BE FILLED TO ITS PERMANENT POOL ELEVATION -- ---- ---------------- - 1 9. INSTALL POND LANDSCAPING PER THE SPECIFICATIONS AND SCHEDULE OUTLINE ON SHEET SWM5 OF THIS PLAN SET. POND ELEVATION MAY REQUIRE MANIPULATION TO ALLOW J VEGETATION TO ESTABLISH. N J 0 z \ \ \ 10. VERIFY PERMANENT POOL ELEVATION PER SPECIFICATIONS OF THIS SHEET W = a J - -}- � ONCE THE CONVERSION IS COMPLETE AND THE POND S OPERATING IN ACCORDANCE WITH ITS DESIGN THEN THE ENGINEER OF RECORD MUST SUBMIT SEALEDAS BUILT RECORDS AND < � - - - - - - - h O _ _ - _ _ _ � - - - _ - _ •/�'� � ALSO ANY GEOTECHNICAL RECORDS TO THE CITY OF WINSTON-SALEM STORMWATER ENGINEER AS OUTLINED IN SEQUENCING NOTES ON EARLIER EROSION CONTROL PLANS IN THIS LLJ a .S 90 - - - _ - - - - - - --- _ - ' - - \ OVERALL PLAN SET. � . - - - -,� - - - - a NOTES: do= PIPE DIA U I 1. SEE SCHEDULE FOR DIMENSIONS. La =APRON LENGTH OUTLET STABILIZATION DETAIL I O -- , - 2. INSTALL A FILTER BLANKET OR W=APRON WIDTH C/) Z - _ - 7 FILTER FABRIC BETWEEN THE do+ La NOT TO SCALE LLI O _ _ _ _ sF RIPRAP AND SOIL FOUNDATION. d =APRON DEPTH _ _ _ _ _ - - - - - - - - - - - - - - - - - - - / IC SHALL BE - sF 3 FILTER FABRIC W - S F_ SF - - - sF��sF� SF_ SF- SF_ sF� 500 OR EQUAL. PLAN Pipe apron NCDOT � � a SF_SF_ �Q sF_ \ SF- SF- SF-----' Outlet Discharge d50 La W dmax Q -� sF ®- SF- SF- _ SF- sF� \ A A Diameter thickness riprap � Q I (in) (cfs) (ft) (ft) (ft) (ft) (ft) Class I 100 42 91.96 0.80 27.0 30.5 1.2 1.8 1 W z co J a C7 I I1 200 15 4.79 0.30 8.0 9.3 0.5 0.7 A z _ / II 9O 300 18 0.38 0.30 10.0 11.5 0.5 0.7 A - a Sj_ Pond 24 7.50 0.40 13.0 15.0 0.6 0.9 B WET POND 1 PLAN VIEW LEGEND M SEGMENT FEATURE ELEVATION A TOP OF DAM 911 O B BOTTOM OF POND 900.5 C TOP OF SEDIMENT STORAGE m U N 901 00 L C:)0 a to GRAPHIC SCALE 80 Summary of Water Quality Management ZONE IN MAIN POOL N � 3: � N D PERMANENT POOL 907 C? Management Aspects Pond 1 E TOP VEGETATED SHELF 907.5 La N o Required Provided F BOTTOM VEGETATED SHELF 906.5 SLOPE 0 ( IN FEET ) Water Quality Volume (co 29,096 32,585 G TOP OF FOREBAY 906.5 _ FLOW 6"THICK LAYER OF#57 STONE 1 inch = 20 ft. Water Quality Elevation (ft) 908.57 908.75 H BOTTOM OF FOREBAY AT 900 ;„" " _ Main Pool Surface Area sf 10,343 13,438 ENTRANCE -III-III-III-III-I I I�I I III=11 J I I I I I I z m ( ) _ _ -III=III=III=III= z } BOTTOM OF FOREBAY AT 900.5 II11 11I I I 1 �I I I� �I I I� �I� III-III-III-I I C) z o EXIT I I=1 I I=1 I I=1 11= w TOP OF SEDIMENT STORAGE d 3: U W CLASS B RIP RAP d 0 U 0 ZONE IN FOREBAY 901 SECTION A-A 9"MIN. DEPTH FILTER FABRIC 14' 907.5 907 �OL9107.5 L K 8" D.I. POND DRAIN SEE SHEET SWM6 z - - - - -I -I -I III-III-III-III-III-III-I Iui - -I -III-III-III-III-III-III-III-III-III-III-III-III _ NON-WOVEN GEOTEXTILE LINE o - -1 z � � J w FOREBAY BAFFLE WITH RIP RAP WEIR a Q w 100 YR. PEAK:909.5 NOT TO SCALE 1 YR 24 HR PEAK:908.92 RIP RAP FOR ACCESS O � OO PROVIDED WQV ELEVATION:908.75 TO RISER _ H cn to to U SEED AND MAT DAM > ❑ Ir w v v v w❑ REQUIRED WQV ELEVATION:908.57 w PERMANENT POOL:907.00 REST OF WEIR:908.75 EMBANKMENT IMMEDIATELY 0- Of Of � af 6'VEGETATED SHELF STOP WIDTH 2.50"0 RASH RACK VEGETATED SHELF AFTER CONSTRUCTION 0 D_ a a a (12:1 SLOPE) ARTHEN FOREBAY DRAWDOWN 906.5-907.5 10, LL TOP OF SHELF:907.5 BAFFLE(SIDE SLOPES 3:1) ORIFICE WIT (6 FT WIDE) EARTH DAM TO BE COMPACTED TO 98% M w w w w TOP OF EMBANKMENT 911.00 BOTTOM OF SHELF:906.5 TRASH RACK TOP OF EMBANKMENT 911.00 OF THE STANDARD PROCTOR MAXIMUM w w w w pJ� - - DRY DENSITY(ASTM-D698). NO ORGANIC LO of -III M ON I I 1=1 11=1 11=1 11=1 I I-_ P _ MATERIAL WITHIN DAM EMBANKMENT 3 EMBANKMENT CONSTRUCTION SHALL BE MONITORED AND COMPACTION TESTED BY w o 0 0 0 0 N N N N N i- _ _-III=III III I=1I - I1.-III- ON-SITE GEOTECHNICAL ENGINEER. ON-SITE SOILS MAY BE SUITABLE FOR POND Q a a = = Q Q Q SAND FILTER DIAPHRAGM- ❑ c\ c\ - _III=111- BOTTOM AND EMBANKMENT FILLS. THE CONTRACTOR MAY BE REQUIRED TO OBTAIN a =III-I I -III-III-III- III- III-III-_ NCDOT 2s SAND a a o PERMANENT POOL VOLUME=57,885.00 CF _ _ _ _ �J - I I=1I II I I(REINFORCED 11I II I II I111 =1I I II III-- SUITABLE SOIL FROM ON-SITE IN AREAS OUTSIDE OF THE POND LIMITS. THE o ¢ m U ❑ w �v _=_=III=III=III=III= OWNERS GEOTECHNICAL ENGINEER WILL APPROVE SOILS FOR SUITABILITY OF z -III III IIII-� . . . . . . . . . . ' ' ' ' ' ' ' ' v II-III-III-III I 1-I CONCRETE PIPE -III-III- I I-I I - I I1=III=1I1 - CLASS III (O-RING) III=III=III =III=III - POND AND DAM EMBANKMENT CONSTRUCTION. COMPACTED MATERIAL SHALL HAVE - _ IIII I I (MIN.557 LB/FT II-III-III-I I 3 I 1-III-I - -1I I- , , , , , , , , , , , , , , , , , , , , , , FLARED END A MAXIMUM PERMEABILITY OF 0.00001 CM/SEC. IF REQUIRED PERMEABILTY LIMITS 3. �-III-III 5'x5' -III III- -III-III-III- � -II- 11-1II- 7 FOREBAY VOLUME=7,,6474 CF. g� =11I-III-III- MA6N POOL VOLUME t 5o,a11.00 CF, INSIDE I I 1-J 1 I- UNIT WEIGHT) III=111=1I1=1I I I I 1-1I1=1 SECTION CANNOT BE MET WITH ON-SITE SOILS, THE OWNER, ENGINEER AND GEOTECHNICAL WET POND 15.3%OF PERMANENT POOL -III-1 I f-1 I I-1 I1= -I I I-11 I=11 I=11 I=11 '=IIII I111 OUTLET ENGINEER SHALL DETERMINE A SUITABLE METHOD TO MEET PERMEABILITY =11 -I III-III-1I1-1I1-1 I I - - -_ VOLUME _ _ _ ° _ DR OUTLET PAD REQUIREMENTS. THIS MAY INCLUDE IMPORT OF SOIL MATERIAL FROM OFF-SITE, 111-1 I I-' I I ITI 11=1II=1I1=1 I H I I ' 42"OUTLET PIPE LENGTH=46 LF SLOPE @ 1.19/° III-III-III-III-I I I I=III=- ELEV. ELEV. 11I-111=11I-III-III=111=1I 9o1.so - _ _ - _ �� DETAIL _ INV 901.5 - 11-III III III DIAPHRAGM \ \\� \� AMMENDMENT WITH BENTONITE OR INSTALLATION OF IMPERMEABLE LINERS THE =111=1 11=1I'1=1I'1=111=111=111=III=1 � � � � � III=11 - !•.',.,W-y e .': . r, ':.. - - =111=111-1I1- , . • . . f. = 1 t$5b4t. A,.r „.,„ ..wwy tl �r,�q��.'4'4 .�y..,+•i�'• =111=1I1-1I1-1I1 ELEV.900.50 .>r //\j \/ \i \//\� \\\ j,/\\ /\/ \//\i \ \\\ / -11 = \ \\\ //\\ \i \//\� \ \\ /\\ \� \� . I_ _ t;�. .4jYy'h`�tiP y,!ww�•i•..F;a •,•4:.� •-:: d.. T n. �X. .• // \//\\ /\� \//\\ //\\ /\i\\//\i \//\\ //\\ 11 /\\ //\\ /\i\\ /\� \//\\ //\\ /\ �� \- IMPORTED MATERIAL IL AMENDMENT AND IMPERMEABLE LINER WILL BE ,1 I 1 - '.xt�ti �� s a;4..;it,.,..� ..x...;r� ,�. r.•. - � � / \� \ \� \/i\\\ i\�\\\\\/�\i \� \/i\\\ i\i\\\ =111=111 111 /i\\\ i\�\\\/i\i \//\� \\ ��\\j\� i�� O SO S S -III-1 .A•..wwr,,yy y. .a'x - -_/ \/%\ /%/\\/j/\\/%/ \/%\ /%/ /j/\\/% \%j\\\ \/\\ �\ \\ ,/\\\.,\ ,��\\�\\\%� \\�/j\%\\\ \\�\\/%\ 111 - - /\\\ \\�\\\//\\/\\ ,� \\\ ��\\\ ,�� / 6"scH.so CONSIDERED ADDITIONAL COST. SHEET I-III-III-III=1I I-III-1I I-1I I-III_ I10.01 6"SCH.80 SOLID PVC (SQUARE DIM.) ANTI-FLOTATION PERFORATED PVC EXISTING SOILS TO BE USED FOR POND BOTTOM AND (CONCRETE) EMBANKMENT MATERIAL TO HAVE A MAXIMUM REMOVE ORGANIC MATERIAL& SHEET PERMEABILITY OF 0.01 IN/HR. ROOT MAT FROM BENEATH 5'Dx5'W CUTOFF TRENCH EMBANKMENT ALONG ENTIRE LENGTH OF WET DETENTION BASIN CROSS-SECTION DAM EMBANKMENT SWM 5 14'LONG 8"D.I. POND DRAIN POND DRAIN WILL ONLY DRAIN POND DOWN TO 901.50. PROVIDE 8"RESILIENT WEDGE GATE NOT TO SCALE A PUMP WILL BE USED TO DRAIN THE VALVE AND OPERATING HANDLE. REMAINING 0.5'TO TOP OF SEDIMENT STORAGE SEAL RISER PENETRATION. SEE DETAIL.