HomeMy WebLinkAboutErosion and Sediment Control Workshop - Builders ForumEROSION AND SEDIMENT CONTROLWORKSHOP – BUILDERS FORUMErosion Sediment SedimentationPREPARED BY
OverviewOverviewOverviewOverview1. Background2. Issues and Opportunities3. Building Practices - Do’s and Don’ts4. New Requirements5. The Next Step
Why Are We Here?Why Are We Here?Why Are We Here?Why Are We Here?• Unique Topography• Record rainfall events• High growth rate• Outdated practices• Agency Downloading• Public Concerns• Council Directive
Key Issues With Past Practices1.Outdated Standards and PracticesOperating in a Spirit of Cooperation1.Outdated Standards and Practices2. Inconsistent Requirements for All Players3. Confusion over Responsibilities4. Lack of Enforcement
Issues With Past PracticesTypical BMP’s have not been successful at removing suspended sediments to within DFO lawful limits prior to discharge.Sediment control is the last line of defenceTraditional Efforts included:Hay BalesSediment FenceSediment trapsFilter fabricsWet detention pondsPolyethylene slopes and soil moundsTesting site (Surrey) has NOT been able to reduce turbidity levels to acceptable limits using ONLY BMP’s outlined in the Land Development Guidelines.
Inconsistent Requirements For Inconsistent Requirements For Inconsistent Requirements For Inconsistent Requirements For Developers and BuildersDevelopers and BuildersDevelopers and BuildersDevelopers and Builders
Complex Terrain and Soils with no or limited focus on source controls
Large Scale Clearing of sites
Inconsistent onInconsistent onInconsistent onInconsistent on---- site and offsite and offsite and offsite and off---- site site site site maintenance practicesmaintenance practicesmaintenance practicesmaintenance practicesUn-maintained roads leads to large volumes of sediment transported into catch basins and municipal stormwater systems.
Poor Installation, Monitoring and Maintenance of Controls on Sites
Why Bother?Why Bother?Why Bother?Why Bother?1. Water quality degradation in fish and nutrient bearing watercourses. 2. Cost increases for the developer, civil contractor and home builders for remedial measures and delaysremedial measures and delays3. Property damage and increasing legal and social responsibility to deal with erosion / sediment both on and off site.4. Legal obligation to Department Fish and Oceans and provincial Water Act
Why Bother?Why Bother?Why Bother?Why Bother?1. Stop work ordersfor discharge of highly turbid or sediment laden stormwater.stormwater.2. Larger tickets –up to $1,0003. Larger fines for convictions –from $2,000 up to $10,000
What’s New in the Lower Mainland?DFO legal limits for stormwater discharge are 25 mg/l during non-storm conditions and 75 mg/l during storm conditionsExtensive erosion and Extensive erosion and sediment control program. This also includes digital sensor systems, increased monitoring, large security deposits and hefty fines.Approximately75 NTU
How was the new Bylaw developed?1.Reviewed other municipal bylawsCity of Burnaby Township of LangleyCity of Coquitlam City of SurreyCity of Abbotsford District of North Vancouver 2. Reviewed with various staff and departments3. Reviewed existing literature and reports by environmental consultants4. GAP analysis and integration of existing Watercourse Protection Bylaw and other relevant bylaws.
Erosion and Sediment Control StrategyErosion and Sediment Control StrategyErosion and Sediment Control StrategyErosion and Sediment Control StrategyThe strategy for this sediment and erosion control plan is one that seeks to provide: 1. Pro-active approach for erosion and sediment control.2.Greater clarity and consistency 2.Greater clarity and consistency 3. A more integrated approach4. More efficient use of professional resources and practices.
Who is responsible?Who is responsible?Who is responsible?Who is responsible?1. No person shall cause or permit any Prohibited Material, or water containing Prohibited Material to be released, directly or indirectly into the Drainage System.2. No person shall obstruct or impede the flow of any Drainage System.any Drainage System.
A A A A ProProProPro----Active ApproachActive ApproachActive ApproachActive ApproachThe most cost-effective and efficient strategy is to focus on pro-active measures at the source: 1. Install basic primary erosion control measures prior to any construction works taking place. 2. Protect the existing vegetative cover, setback areas, and controls on site.areas, and controls on site.3. Schedule construction works for drier periods i.e. May 15 to October 15 where possible.4. Ensure regular inspection and maintenanceof erosion and sediment control facilities as well as adjacent roads.
1. EROSION CONTROLAccess Pads and Staging Areas for VehiclesPolyethylene cover for slopes and stockpilesErosion control is the first line of defensein preventing sediment laden water discharging from construction sites. Erosion control features include but are not limited to:Mulching of soils, Hydro-seeding and Tackifiers for stabilizing disturbed soilsProtect vegetated and protected areas where possibleTerraced slopes and Water Diversions on steep slopesTiming of works in drier periods
Protect the soil surfaceProtect the soil surfaceProtect the soil surfaceProtect the soil surface1. Protect the soil surface – Every effort should be made to limit the extent of disturbance and stabilize soil surfaces immediately. •Access areasmust have a gravel pad in place with a staging area for construction vehicles.•Disturbed soils must be immediately protected•Disturbed soils must be immediately protectedwith appropriate cover, such as poly, mulch, straw matting, or vegetation. •Protect vegetated areaswhere possible and ensure protection of watercourse setback areas using temporary fencing.•Schedule constructionto dry months and phase works to minimize clearance of vegetation.
Cover stockpiles and remove from road side
Ensure Site Contain Necessary Facilities1. Access Pads2. Staging Area Wheelwash Facilities3.Perimeter ditch3.Perimeter ditch4. Silt Fences5. Temporary Fences6. Sediment Traps7. Stockpile Area to be covered.
Identify and Protect Boundaries
Stabilize, cover, or re-vegetate slopes
Control surface runoffControl surface runoffControl surface runoffControl surface runoff2. Control surface runoff– Surface runoff from undisturbed areas will be diverted away from disturbed areas. • Long running slopes (including your access road and linear trenches / ditches) will be broken up with diversion controls to reduce velocity of runoff. diversion controls to reduce velocity of runoff. • Any sediment-laden water should be diverted to sediment control structures, traps, and on site vegetated infiltration areas. • Re-vegetate and stabilize disturbed areas as soon as practically possible (within 30 days of completion of construction works before October 15 where possible.)
3.3.3.3.Control surface runoffControl surface runoffControl surface runoffControl surface runoffBeforeAfter
Line channels with geotextile and bafflesPump water to a collection (disposal) sump
Surface Runoff Surface Runoff Surface Runoff Surface Runoff –––– Cover Steep SlopesCover Steep SlopesCover Steep SlopesCover Steep Slopes
2. SEDIMENT CONTROLSediment PondsSediment control is the last line of defensein preventing sediment laden water discharging from construction sites. Sediment control features include but are not limited to:Sediment PondsCheck DamsConveyance SystemsSediment TrapsBiofiltration SystemsFlocculation Systems
Capture sediment onCapture sediment onCapture sediment onCapture sediment on----sitesitesitesite3. Capture sediment on-site–• The drainage channels will be lined with clean drain rock, check dams and silt fences, and convey water to silt traps or an appropriately sized siltation pond• Sediment control facilities will be regularly maintained / cleaned out and for proper disposal of maintained / cleaned out and for proper disposal of the trapped sediment. • No Concrete truck wash, construction wash of exposed aggregate surfaces, or chemicals are to be directed into any drainage system or catch basin.
MaintenanceMaintenanceMaintenanceMaintenance4. Maintenance and Good Housekeeping• Regular maintenanceof all erosion and sediment controls is required.•Roadways (fronting the respective lots) are to be swept freeand cleaned of accumulated soils, fines/sediments on a regular basis (at least once fines/sediments on a regular basis (at least once a day during rain events). •The contractor shall provide on-site disposal facilities at all times and disposed of on a regular basis. • Remove all temporary control measures and construction materials at the end of the project and ensure soils have been vegetated.
Maintenance Issues
Regular Maintenance
Monitoring and ReportingMonitoring and ReportingMonitoring and ReportingMonitoring and Reporting5. Inspection and Monitoring• Regular inspection and monitoringof all erosion and sediment controls is required by contractors as well as environmental monitors.•Requirement for monitors to ensure compliance through maintenance, modification of controls, through maintenance, modification of controls, adaptation of activities, and/or shut down the site. •Proper installation and maintenance of facilities can sometimes be complex.
Expertise in InstallationExpertise in InstallationExpertise in InstallationExpertise in Installation
Appropriate Sizing and Design
Inspection and Compliance
Greater Responsibility for Professionals1. Provide clear standards and basic checklist of erosion and sediment control requirements2. Review and approval of ESC plans by both professional engineer and the monitorprofessional engineer and the monitor3. Pre and post development inspections required by environmental monitor before final approval 4. More emphasis on the monitoring and maintenance responsibilities.
New Requirements For DevelopersNew Requirements For DevelopersNew Requirements For DevelopersNew Requirements For Developers1. Provide a more comprehensive erosion and sediment control plan.2. Provide A BCLS Surveyed Comprehensive Grading PlanGrading Plan3. Provide an environmental security deposit for each lot until final approval. 4. Ensure gravel pads are in place for each lot
New Requirements For BuildersNew Requirements For BuildersNew Requirements For BuildersNew Requirements For Builders1. Small Scale building application ESC requirements.2. Environmental monitors and security deposits are required for some building applications depending on the following:• the size of project, • complexity of site, and • timing of construction works. • status of the site with respect to development approvals and Certificate of Acceptance.3. Large Scale building applications with larger security deposit, monitoring, and ESC plan are required.
Potential Exemptions Potential Exemptions Potential Exemptions Potential Exemptions 1. Construction timingand schedule that is conducive to drier periods (April 16 – Oct.14) as opposed to rainy periods (Oct.15-April 15)2. Size and locationof the proposed Construction Works with respect to the Construction Works with respect to the perimeter and sensitivity of the parcel of land. 3. Slope and soil conditionson the parcel are conducive to infiltration and pertinent to drainage.
Municipal PracticesMunicipal PracticesMunicipal PracticesMunicipal Practices1. Erosion and sediment control requirements need to be in place before clearing or construction works proceed. Pre and post construction inspections are required.2. Regular reporting of monitoring and maintenance of erosion and sediment maintenance of erosion and sediment controls on site is required of monitors.3. Stronger enforcement related measures where infractions occur including use of stop work orders, fines, and use of environmental security deposit.
Enforcement MeasuresEnforcement MeasuresEnforcement MeasuresEnforcement MeasuresMunicipal Ticketing• Additional effort by District staff to carry out Municipal enforcement and ticketing system•Tickets up to $500 for offences including •Tickets up to $500 for offences including sediment discharge, failure to comply with ESC permit, and failure to maintain logbook.
Enforcement MeasuresEnforcement MeasuresEnforcement MeasuresEnforcement MeasuresFines• Contravention of bylaw liable for fines from $2,000 up to $10,000 per dayEnvironmental Security Deposit• Costs incurred by the District will be deducted from the security deposit
The Next Steps The Next Steps The Next Steps The Next Steps 1. Council hearings and adoption of new Watercourse Protection Bylaw.2. Education and awareness sessions•Spring and fall workshops•Spring and fall workshops• Website materials3. Consider moderate measures over the next couple of years and re-evaluate whether tougher controls are required.
The Next Steps The Next Steps The Next Steps The Next Steps ––––Improve Watercourse QualityImprove Watercourse QualityImprove Watercourse QualityImprove Watercourse Quality