Attachment 19. Erosion and Sediment Control Plan - Associated Engineering

FIGURE No.1: LIMONA CONSTRUCTION WEST PARK @ THETIS

CIVIL EROSION & SEDIMENT CONTROL PLAN

Project Information

• AE Project No.: 2016-2253-00
• Scale: 1:500
• Approved: DD
• Date: 2020NOV6
• Rev: A
• Description: ISSUED FOR APPROVAL

Site Plan Overview

The plan outlines the erosion and sediment control measures for Phases 1 through 6 of the West Park @ Thetis development. Key features include:

• Construction Entrances: Two stabilized construction entrances with tire wash details.
• Storm Management:
  • Temporary lawn basin discharging to Phase 3 storm.
  • Temporary lawn basin discharging to Phase 1 storm.
  • Sediment control ditch.
• Drainage Design Data:
  • Phase 3 Ditch: Design Flow 10YR = 63.1 L/S, Velocity = 0.925 M/S, 1 M BW, 3H:1V, 10KG.
  • Phase 6 Ditch: Design Flow 10YR = 20.04 L/S, Velocity = 0.44 M/S, 1 M BW, 3H:1V, 10KG.
• Perimeter Controls: Silt fencing (TYP) around the lower boundaries of the site.
• Easement: EASEMENT PLAN EPP92347.
• Road Construction Note: Grade road to drain to ditch/swale during road construction. Once road paved, deactivate ditch/swale and protect catchbasins using filter inserts.

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Detail 1: SEDIMENT CONTROL DITCH

The detail includes a typical section view and typical profile view showing check dam spacing (S), ponded water, and riprap requirements.

Sediment Control Ditch Specifications

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Detail 2: SILT FENCE DETAIL

Includes side view and profile diagrams for silt fence installation.

Silt Control Notes:

1. PERMITTIVITY OF GEOFABRIC TO BE ~ 10L/S/m2.
2. SPLICES TO BE AT POSTS SUCH THAT EACH PIECE IS WRAPPED FULLY AROUND POST.
3. SILT FENCE TO HAVE AN EFFICIENCY >75%. WHERE EFFICIENCY IS LESS THAN THIS EMPLOY SUCCESSIVE FENCES TO REACH THE DESIRED AMOUNT.
4. AT COMPLETION OF WORK SILT TO BE REMOVED AND DISPOSED OF.

Construction Requirements:

• 38x89 wood post @ 1.5m max. spacing.
• Woven, silt film geotextile designed to reduce velocity of runoff; min grab tensile strength = 500N.
• Minimum fabric embedment = 150mm such that flow can pass under frame.

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Detail 3: SWALE CROSS SECTION

• Width: 2.4m wide
• Depth: 0.3m deep

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Detail 4: STABILIZED CONSTRUCTION ENTRANCE & TIRE WASH

The detail provides a plan view and sections (AA and BB) for a stabilized entrance.

• Material: 300mm of crushed aggregate greater than 75mm but smaller than 150mm.
• Gravel: Use well graded, 50mm minus gravel at construction entrance.
• Features: Wheel wash sump (5m min), water supply/hose or automatic sprayer, and temporary lawn basin.
• Drainage: Swale conveying runoff to sediment sump. Water to be pumped from sump into settling tanks or Stormceptors once they are installed.

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SEDIMENT & EROSION CONTROL NOTES

The contractor shall be responsible for maintenance and inspection of all sediment and erosion control facilities, shall provide regular inspection reports to the civil engineer and shall coordinate any remediation required by the engineer.

All practical and necessary effort should be taken during construction to control and prevent erosion and the transport of sediment to surface drains, surface water or onto other property by any or all of the following methods:

1. CONSTRUCT A STABILIZED CONSTRUCTION ENTRANCE AND WHEEL WASH;
2. DIRECT ALL STORMWATER DISCHARGE TO EXISTING STORM SYSTEM THROUGHOUT CONSTRUCTION;
3. STABILIZED CONSTRUCTION ENTRANCE TO REMAIN IN PLACE UNTIL EXCAVATION AND GRADING IS COMPLETE AND ALL SURFACES ARE STABILIZED;
4. TEMPORARY SEDIMENT AND EROSION CONTROL MEASURES SUCH AS SILT FENCE AND STREET SWEEPING ARE TO BE EMPLOYED WHEREVER NECESSARY TO PREVENT MIGRATION OF SEDIMENT OFF-SITE. NEARBY OFF-SITE STREETS AS WELL AS COMPLETED ON-SITE PAVING MUST BE KEPT CLEAN THROUGH REGULAR STREET SWEEPING. DURING CONSTRUCTION, THESE MEASURES SHALL BE REGULARLY INSPECTED AND REPLACED OR EMPLOYED AS REQUIRED OR AS DIRECTED BY THE CIVIL ENGINEER. SILT FENCE TO BE INSTALLED DOWN GRADE FROM EXCAVATED OR DISTURBED AREAS UNTIL SURFACES ARE STABILIZED;
5. DURING DRY WEATHER, SPRINKLERS ARE TO BE PLACED ADJACENT TO EXCAVATION OR GRADING ACTIVITIES TO PREVENT DUST FROM LEAVING THE SITE;
6. DUST CONTROL FABRIC TO BE INSTALLED ON TEMPORARY CONSTRUCTION FENCING AS REQUIRED TO PREVENT DUST MIGRATION;
7. ALL DRAINAGE INLETS SHALL BE PROTECTED FROM SEDIMENTATION WITH FILTER CLOTH DURING CONSTRUCTION. THIS PROTECTION SHALL BE INSPECTED WEEKLY AND AFTER ANY SIGNIFICANT RAINFALL EVENT. FILTER FABRIC SHALL BE REPLACED AS IT BECOMES BLINDED WITH SEDIMENT OR DAMAGED, OR AS DIRECTED BY THE CIVIL ENGINEER;
8. IT IS THE CONTRACTOR'S RESPONSIBILITY TO ENSURE GRADES ARE MAINTAINED IN SUCH AS WAY THAT ALL STORMWATER RUNOFF IS DIRECTED TOWARD STORMWATER CONTAINMENT FACILITIES;
9. NO STOCKPILING OF GRANULAR MATERIAL IS PERMITTED ON PAVED SURFACES. ANY EXISTING MATERIAL BEING STOCKPILED AS PART OF SITE GRADING EXERCISES SHALL BE PLACED WITHIN 3 DAYS OR SURROUNDED BY SILT FENCE TO CONTAIN EROSION. SILT FENCE SHALL BE INSTALLED DOWN GRADE FROM PRE-LOAD MATERIAL;
10. COMPACTION AND/ OR VEGETATION OF DISTURBED GROUND SURFACES SHALL BE ACCOMPLISHED AS SOON AS POSSIBLE AND PRACTICAL;
11. THE USE OF ANY CONSTRUCTION EQUIPMENT THAT LEAKS EXCESSIVE AMOUNTS OF FUEL, OIL OR HYDRAULIC FLUID IS PROHIBITED;
12. ANY SPILLAGE OF HAZARDOUS MATERIALS OR MATERIALS WHICH MAY BE DETRIMENTAL TO THE ENVIRONMENT MUST BE CLEANED UP IMMEDIATELY AND THE PROPER AUTHORITIES MUST BE NOTIFIED, AS REQUIRED BY LAW;
13. UPON COMPLETION OF CONSTRUCTION, ANY ACCUMULATED SEDIMENT IS TO BE REMOVED FROM ALL SUMP INLETS, CATCH BASINS AND STORM MANHOLES;
14. UPON COMPLETION OF CONSTRUCTION, TEMPORARY SEDIMENT AND EROSION CONTROL MEASURES SUCH AS SILT FENCE, SHALL BE REMOVED.
15. MONITOR SEDIMENT LEVELS IN STORMCEPTOR UNTIED AFTER RAINFALL EVENTS. CLEAN AS REQUIRED DURING CONSTRUCTION AND WHEN CONSTRUCTION IS COMPLETE.