hanley stormwater plan review - municipal association and public works/for... · bmps identified...
TRANSCRIPT
9/9/2016
1
REGULATIONS, PERMITS & ORDINANCESCHECKLISTMEETINGSC-SWPPP AND ON-SITE SWPPPBMPS PER THE CGPCONSTRUCTION PLANSENGINEERING REPORT
REGULATIONS, PERMITS AND ORDINANCES ARE THEFOUNDATION FOR STORMWATER PLAN REVIEW.
9/9/2016
2
STANDARDS FOR STORMWATER MANAGEMENTAND SEDIMENT REDUCTION (Reg. 72-300 – 316)EFFECTIVE JUNE 28, 2002.
NPDES GENERAL PERMIT FOR STORMWATERDISCHARGES FROM CONSTRUCTION ACTIVITIES,(CGP) EFFECTIVE JANUARY 1, 2013.
STATE OF SC NPDES GENERAL PERMIT FORSTORMWATER DISCHARGES FROM REGULATEDSMALL MUNICIPAL SEPARATE STORM SEWERSYSTEMS (SMS4) EFFECTIVE JANUARY 1, 2014.
DETENTION STRUCTURE – PERMANENTSTORMWATER STRUCTURE CONTROLINGRELEASE RATE
RETENTION STRUCTURE – PERMANENTSTORMWATER STRUCTURE STORING A VOLUMEOF STORMWATER RUNOFF. RELEASE ISTHROUGH INFILTRATION OR EVAPORATION.
QUANTITATIVE CONTROL – A SYSTEM OFVEGETATIVE OR STRUCTURAL MEASURES, ORBOTH THAT CONTROL THE INCREASED VOLUMEAND RATE OF STORMWATER RUNOFF.
QUALITATIVE CONTROL – A SYSTEM OFVEGETATIVE, STRUCTURAL OR OTHERMEASURES THAT REDUCE OR ELIMINATEPOLLUTANTS.
9/9/2016
3
ADVERSE IMPACT MEANS A SIGNIFICANTNEGATIVE IMPACT TO:
LAND,WATER ANDASSOCIATED RESOURCES
RESULTING FROM A LAND DISTURBING ACTIVITY.
THE NEGATIVE IMPACT INCLUDES:
INCREASED RISK OF FLOODINGDEGRADATION OF WATER QUALITYINCREASED SEDIMENTATIONREDUCED GROUNDWATER RECHARGENEGATIVE IMPACTS ON AQUATIC ORGANISMSNEGATIVE IMPACTS ON WILDLIFE AND OTHERRESOURCES; ANDTHREATENED PUBLIC HEALTH.
PROJECT WILL HAVE NO SIGNIFICANT ADVERSEIMPACT ON THE RECEIVING NATURALWATERWAY OR DOWNSTREAM PROPERTIES; OR
THE IMPOSITION OF PEAK RUNOFFREQUIREMENTS FOR RATES OF STORMWATERRUNOFF WOULD AGGRAVATE DOWNSTREAMFLOODING.
9/9/2016
4
72-307 C (4) – DETENTION REQUIREMENTS (2AND 10 YR 24 HOUR)
72-307 C (4) - NON-EROSIVE VELOCITYREQUIREMENTS (10 YR 24 HOUR)
72-307 C (5) - 80% SEDIMENT TRAPPINGEFFICIENCY (10 YR 24 HOUR)
72-307 C (5) – INFILTRATION PRACTICES MUSTACCEPT 1ST INCH FROM ALL IMPERVIOUSAREAS.
72-307 C (11) – INFILTRATION PRACTICES – 10ADDITIONAL REQUIREMENTS.
72-307 D – VECTOR CONTROL DESIGN CRITERIA.
72-307 C (5) – PERMANENT WATER QUALITYPONDS WITH A PERMANENT POOL – MUSTSTORE AND RELEASE THE FIRST ½ INCH OVER 24HRS. THIS IS FROM THE ENTIRE SITE.
72-307 C (5) – PERMANENT WATER QUALITYPONDS WITHOUT A PERMANENT POOL MUSTRELEASE THE FIRST INCH OVER 24 HOURS.
9/9/2016
5
SWP3 MUST COMPLY WITH TECHNICALREQUIREMENTS OF CGP.
SWP3 MUST INCLUDE RATIONALE FORCONTROL MEASURES – HOW THEY PROTECT AWATERWAY OR CONVEYANCE.
SWP3 MUST DEMONSTRATE THATSTORMWATER DISCHARGES WILL NEITHERCAUSE NOR CONTRIBUTE TO WATER QUALITYVIOLATIONS.
CONSTRUCTION PROJECTS 25 ACRES ORGREATER IN TMDL OR 303D WATERSHED MUSTHAVE A WRITTEN QUANTITATIVE ANDQUALITATIVE ASSESSMENT SHOWING THATSELECTED BMP WILL CONTROL THE DISCHARGEOF POLLUTANTS OF CONCERN FORCONSTRUCTION AND POST-CONSTRUCTIONDISCHARGES.
PROJECTS DISTURBING 1 ACRE (+LCP) OR MOREMUST DESIGN, INSTALL, IMPLEMENT, ANDMAINTAIN STORMWATER CONTROL MEASURESTHAT APPROXIMATE PREDEVELOPMENTCONDITIONS TO THE MEP AND PROTECT WATERQUALITY.
NEW DEVELOPMENT STANDARDS TO BE USEDCAN BE A VARIETY OF CONTROL MEASURES,BUT THE FIRST INCH OF RUNOFF MUST BEADDRESSED.
9/9/2016
6
RETENTION OF A MINIMUM STORM VOLUMEEX. 1ST INCH.
RETENTION OF A MINIMUM STORM SIZE EX.95TH PERCENTILE RAINFALL EVENT.
HYDROLOGIC ANALYSIS – POST RATE, VOLUME,DURATION AND TEMPERATURE OF DISCHARGESDOES NOT EXCEED THE PREDEV. RATES ANDHYDROGRAPH FOR THE 1,2,10,25,50 AND 100YEAR STORMS.
GROUNDWATER RECHARGE – INFILTRATE THEINCREASE IN STORMWATER VOLUME FROM PRETO POST FOR THE 2 YR. STORM EVENT.
HYDROLOGIC LOADING CALCULATIONS – POSTCONSTRUCTION ANNUAL POLLUTANT LOADSARE NOT ALLOWED TO EXCEEDPREDEVELOPMENT LEVELS.
4.1.3.1 SMS4 PERMIT – REQUIRES ANORDINANCE OR OTHER REGULATORYMECHANISM PROVIDING LEGAL AUTHORITY TOIMPLEMENT THE SMS4 PERMIT.
CITY OF GREER HAS THREE STORMWATERORDINANCES – STORMWATER MANAGEMENT,ILLICIT DISCHARGE AND MAINTENANCE ANDREPAIR of STORMWATER MANAGEMENTSYSTEMS AND WATER QUALITY DEVICES.
9/9/2016
7
GREER USED THENEW DHECCHECKLIST ANDINSERTEDADDITIONAL CITYREQUIREMENTS.
PLANNING ADVISORY COMMITTEE – CITY STAFF,UTILITIES, SCDOT, ETC.
PRELIMINARY MEETING – OPTIONAL
PRE-SUBMITTAL MEETING – CHECK SUBMITTALFOR COMPLETENESS AND PARTIAL REVIEW
THIS MEETING IS FOR PROJECTS WHERESOMETHING WILL BE BUILT.
APPLICANT SUBMITS A CONCEPTUAL DESIGN ATTHIS MEETING.
APPLICANT RECIEVES COMMENTS FROMPLANNING AND ZONING, FIRE MARSHALL,BUILDING CODES, UTILITIES, SCHOOL DISTRICT,PUBLIC SERVICES, SCDOT, ETC.
STORMWATER REVIEWS ON GIS OR GOES TOSITE OR BOTH.
9/9/2016
8
CHECKLIST AND PLAN REVIEW INVOICE
SUMMARY OF DESIGN AND SUBMITTALREQUIREMENTS SUCH AS DETENTION,PHASING, SKIMMER BASINS, BUFFERS, ONSITESWPPP, ETC.
DESIGN SOFTWARE PREFERENCES ANDSOFTWARE NOT ACCEPTED.
RAINFALL RETURN PERIOD VALUES
BRIEF COMMENTS OR QUESTIONS ONSITUATIONS UNIQUE TO SITE. EX. OFFSITESTORMWATER, BUFFERS, WOS, DISCHARGEPOINT, ETC.
IF SITE HAS SOME CHALLENGES (EX. DISCHARGEPOINT) MAY HAVE A PRELIMINARY MEETINGWITH DESIGN ENGINEER.
9/9/2016
9
RESTRICTS NEW POINT DISCHARGES ONTOADJACENT PROPERTY WHERE THERE WAS NOPREVIOUS DISCHARGE POINT, UNLESS WRITTENPERMISSION FROM ADJACENT PROPERTYOWNER IS PROVIDED.RECOMMENDS A 20 FT. BUFFER BETWEENPROPERTY LINE AND DISCHARGE POINT.PLUNGE POOLS, LEVEL SPREADERS, ETC. MUSTBE PROVIDED WHEN THE NEW OUTLET IS NEARTHE PROPERTY LINE AND NOT DIRECTED TO ANEXISTING OUTFALL LIKE A CREEK OR DITCH.NO DISCHARGE ON FILL SLOPES.
SOUTH CAROLINA DRAINAGE LAW USES WATERAS THE COMMON ENEMY RULE.THIS MEANS WATER IS A COMMON ENEMY TOALL UNLESS YOU CONCENTRATE IT. THEN ITBECOMES A LIABILITY TO THE ONE THATCONCENTRATES IT.
9/9/2016
10
DESIGN ENGINEER BRINGS PLANS,CALCULATIONS, NOI AND ONSITE SWPPP TOMEETING.
PLANS - REVIEW OF TITLE PAGE, STANDARDNOTES, EXISTING CONDITIONS, DEMOLITIONPLAN, AND EROSION CONTROLS.
PLANS - WOS/WETLAND DELINEATIONS,BUFFERS, BUFFER REDUCTIONS, SURFACEWITHDRAWAL. DISCUSS SURFACE WATERPROTECTION PLAN
PLANS – BAFFLES AND FOREBAYS, DETAILS,(INLET PROTECTION, ETC.)
CALCULATIONS – REVIEW OF CN, TC, DA MAPS,RAINFALL RETURN PERIOD VALUES, AND PONDDATA REPORT.
CALCULATIONS (? PRESENT) – REVIEW OFWATER QUALITY CALCULATIONS, SKIMMERSIZING, SEDIMENT TRAPPING EFFICIENCY,OUTLET PROTECTION SIZING, BUOYANCY, ETC.
CHECK AGAINST
POND DETAILS.
PONDDATAREPORT
9/9/2016
12
FLOODINGPROBLEMS
DETENTIONWAIVER
WETLANDS/WOS
NAVIGABLEWATERS
NOI
Form asks fornearest WQMS.
303 D informationfrom 303 D List.
TMDL informationfrom TMDL
Don’t miss D 1 (f)and 2 (f).
Sec. 122.22 Reg 61-9
NOI
SUBMITTAL IS CHECKED FOR COMPLETENESS.
IT STREAMLINES THE PLAN REVIEW PROCESS.
IF COMPLETE CAN GO TO A CONSULTANT FOR REVIEW.
SMALL AND LINEAR PROJECTS CAN COMPLETE REVIEW.
PROJECT ISSUES CAN BE RESOLVED IN MEETING.
PUBLIC EDUCATION - ENGINEER CAN LEARN SOMEPERMIT REQUIREMENTS.
9/9/2016
13
COMPREHENSIVE SWPPP = ON-SITESWPPP + PLANS + ENGINEERING REPORT
ON-SITE SWPPP = COMPREHENSIVESWPPP – ENGINEERING REPORT
TOPOGRAPHICSOILSVICINITYFLOODWAYDRAINAGE AREA – (PRE AND POST)ADDITIONAL DRAINAGE AREA – (WATERQUALITY AND QUANTITY)
PROJECT DESCRIPTION, (SUBDIVISION, MFG.PLANT, ETC.)PRIOR USES OF SITE (POTENTIAL POLLUTIONSOURCES)DESCRIPTION OF PRE AND POST DEVELOPEDCONDITIONSEXISTING AND POTENTIAL FLOODINGPROBLEMSDISTURBED AREANEED FOR CONCRETE OR ASPHALT BATCHPLANTS.
9/9/2016
14
DRAINAGE AREAS AND ANY OFFSITE SW
SEDIMENT TRAPPING
POST-CONSTRUCTION WATER QUALITY
STORM SEWER SYSTEM
100 YEAR STORM?
QUANTITATIVE/QUALITATIVE ASSESSMENT(3.2.12 B II)
3.2.2 CGP - SW MGT AND SEDIMENT CONTROL
3.2.3 CGP - CONST. SEQUENCE
3.2.4 CGP - WOS/WETLANDS, BUFFERS, BUFFERREDUCTIONS AND MAINTENANCE
3.2.5 CGP - SOURCES OF POLLUTION
3.2.10 CGP A and B – VOLUME and VELOCITYCONTROL, DISCHARGE CONTROL, STEEPSLOPES, SOIL STABILIZATION, ETC.
3.2.10 D AND E CGP – POLLUTANT DISCHARGEMINIMIZATION AND PROHIBITED DISCHARGES
3.2.11 CGP – MGT. OF NON-STORMWATERDISCHARGES
3.2.12 A CGP – TMDLS AND PERMIT ELIGIBILITY
3.2.12 B I – BMP SELECTION ADDRESS INNARRATIVE
3.2.12 B II – QUANTITATIVE/QUALITATIVEASSESSMENT (ADDRESS IN NARRATIVE)
9/9/2016
15
CHECK THESE ITEMS:
HAVE REQUIRED SUBJECTS BEEN ADDRESSED?
DOES ON-SITE SWPPP DISCUSSION MATCHTHEIR SITE?
POTENTIAL POLLUTANT SOURCES TABLE
INSPECTION REQUIREMENTS AND LOGS
DESIGN PROFESSIONAL CERTIFICATION
C-SWPPP MUST ADDRESS USE, INSTALLATION,MAINTENANCE AND INSPECTION OF BMPS
EROSION PREVENTION – EX. STABILIZATIONSEDIMENT CONTROL – INLET & OUTLETPROTECTION, SEDIMENT BASINS, TRAPS ANDSURFACE DEWATERINGRUNOFF CONVEYANCE – PERM AND TEMPCHANNELS (10 YR STORM AND 7 DAYSTABILIZATION), VELOCITY DISSIPATION DEVICESPOST-CONSTRUCTION WATER QUALITY BMPSSTRUCTURAL BMPS, ETC.
9/9/2016
16
CITY OF GREER USES SCDHEC BMP DETAILSWHERE AVAILABLE
HAVE INSTALLATION & MAINTENANCEINSTRUCTIONS
ENGINEERS SHOULD BE FAMILIAR WITH THEM
SHOULD PASS DHEC AUDIT
REDUCED REVIEW TIME
9/9/2016
18
LIMITS OF DISTURBANCE – ALL PLAN SHEETS
BMPS IDENTIFIED – BMP MANUAL SYMBOLS ORLEGEND
CONSTRUCTION SEQUENCE (PHASED)
GRADING AND DRAINAGE PLANS
BMP DETAIL SHEETS
EROSION CONTROL SHEETS
5 TO < 10 ACRES
INITIAL LAND DISTURBANCE PHASE
STABILIZATION PHASE
9/9/2016
19
10 ACRES OR MORE
INITIAL LAND DISTURBANCE PHASE
CONSTRUCTION PHASE
STABILIZATION PHASE
CN ANALYSIS
PRE AND POST HYDROLOGIC ANALYSIS (TOTALAREA DOES NOT CHANGE FROM PRE TO POST)
PERMANENT WATER QUALITY ANALYSIS
SEDIMENTOLOGY (TRAPPING EFFICIENCY)ANALYSIS
STABLE CHANNEL ANALYSIS (TEMP AND PERM.)
AS-BUILT SURVEY (FOR PREVIOUS STRUCTURE)
STORM SEWER ANALYSIS
RIPRAP APRON ANALYSIS
DETENTION ANALYSIS
9/9/2016
20
DETENTION ANALYSIS
FULL POND ROUTING
STAGE-STORAGE-DISCHARGE RELATIONSHIP,
SUMMARY TABLE OF MAXIMUM WSE INDETENTION STRUCTURE
SUMMARY TABLE OF DISCHARGE VELOCITIESAND PEAK INFLOWS AND OUTFLOWS FOR EACHOUTFALL.
CN – PREDEVELOPMENT = EXISTING; USETABLES OR WEIGHTED CN
TC – FLOW PATHS, LENGTH OF SHEET FLOW,MANNING’S N, PAVED/UNPAVED, TOTALLENGTH
DA MAPS – CHECK FOR OFFSITE STORMWATER;SHOULD HAVE THREE MAPS
DETENTION ANALYSIS – MAKE A TABLE
DETENTION ANALYSIS TABLES – COMPARE PRETO POST DEVELOPMENT
HYD # WSNAME
ACRES CN TC 2 YRWSE
10 YRWSE
25 YRWSE
100 YRWSE
INFLOWHYD?
RAIN-FALL
RAIN-FALL
RAIN-FALL
RAIN-FALL
9/9/2016
21
CHECK AGAINST
POND DETAILS ONPLAN SHEETS .
CITY OFGREERREVIEW -PONDDATAREPORT
STABLE CHANNEL ANALYSISAT LEAST 10 YR STORM
SHOW CALCULATION OF Q
PLAN DETAILS MUST MATCH CALCULATION
MULTIPLE CHANNELS – PROVIDE TABLE WITHDIMENSIONS ON PLANS
LABELING CONSISTENCY ON PLAN SHEETS,DETAILS AND CALCULATIONS.
PERMANENT WATER QUALITY ANALYSIS
CHECK DRAINAGE AREA
DRY POND – 1ST INCH RELEASED OVER 24 HRS
MFG. DEVICE – RESEARCH MFG. INFO, SCDOT,OR INFORMATION FROM OTHER MS4S.
RIPRAP APRON ANALYSIS
CHECK CALCULATIONS AGAINST PLAN DETAILS
9/9/2016
22
STORM SEWER ANALYSIS
REG 72-307 C (2) – RATIONAL METHOD OKAYFOR INDIVIDUAL CULVERTS OR STORM DRAINSTHAT ARE NOT PART OF A NETWORK
PREFER HYDRAFLOW STORM SEWER REPORT
READ PROFILES – CHECK FOR SURCHARGING
MUST HAVE LEGEND – STORM EVENT, HGL, EGL
STORM SEWER ANALYSIS
NARRATIVE SHOULD HAVE DISCUSSED EVENTSTHAT ARE PIPED AND LOCATION OF THE 100 YRSTORM EVENT.
SEDIMENTOLOGY
SILT FENCE TRAPPING EFFICIENCY – SEDCAD ORLESS THAN 0.25 DA PER 100 LINEAR FT. OF SF.
SEDIMENT BASINS – TYPICALLY DONE INSEDCAD
OTHER BMPS – USE DESIGN AIDS
SKIMMER SIZING
9/9/2016
23
CITY OF GREERREVIEW - SKIMMERSIZING
SUBMIT CUT SHEETS
IF CHANGINGORIFICE SHOWCALCULATIONS
SEDIMENTOLOGY - SEDCAD
CHECK RAINFALL AND SOILS
STRUCTURE NETWORKING – BMPS?
CONTRIBUTING AREAS – CHECK AGAINST MAP
CN AND TC – CHECK AGAINST CONDITIONS
STRUCTURE DETAIL – CHECK AGAINST PLANDETAIL
CITY OF GREERREVIEW - SEDCADSTRUCTUREDETAIL –
CHECKDIMENSIONS ANDELEVATIONSAGAINST PLANDETAILS DURINGCONSTRUCTION.
9/9/2016
24
CITY OF GREERREVIEW -DISCHARGE TABLE
CHECK USER INPUTFLOWS FROMSKIMMER SIZING
AND
ELEVATIONSOF DROP INLETAND EMERGENCYSPILLWAY
CITY OF GREERREVIEW - SEDCAD –SUBWATERSHEDDETAIL TABLES
CHECK CN AND TC
QUANTITATIVE/QUALITATIVE ASSESSMENT
CONSTRUCTION – TRAPPING EFFICIENCY,DETENTION AND VELOCITY DISSIPATION
POST-CONSTRUCTION – DETENTION ANDVELOCITY DISSIPATION, POST-CONSTRUCTIONWATER QUALITY EFFICIENCY (MAY USE IDEALOR TABLES)
MAY REQUIRE TREATMENT TRAIN