Assessment RFP 06-17 (released July 2017) SRD Requested: - - PowerPoint PPT Presentation

Oyster River / Glenmore Dike Assessment

RFP – 06-17 (released July 2017) SRD Requested: - Condition Assessment - Geotechnical Assessment (incl. Seismic) - Conceptual Upgrades & Cost Est. We proposed to provide the above, plus : - Hydrologic Assessment (study of River Flow Rates) - Hydraulic Modelling & Assessment (study of Glenmore Dike performance during large flow events)

Glenmore Dike Assessment  Condition Assessment - Findings  Unauthorized Recreational Users (ATV / Dirtbikers) have caused minor damage via erosion of accessways  Debris Blocking Drainage Channels  Vegetation Overgrowth has caused Reduced Access to Some Areas

Glenmore Dike Assessment  Geotechnical Assessment via Drilling

Glenmore Dike Assessment  Seismic Stability Assessment

Glenmore Dike Assessment  Hydrologic Assessment via Statistical Analysis of River Flow Data  Hydrotechnical Assessment via 2-D River Modelling (HEC-RAS software)

Glenmore Dike Assessment  Ex. Glenmore Dike Hydrology & Floodplain Mapping were Completed in early- 1980’s

Glenmore Dike Assessment Ex. Glenmore Dike Hydrology & Mapping were Completed in early- 1980’s (1981 to 1984)  WSC Flow Data for Oyster River @ Woodhus Creek Post-1980 Flow Data Pre-1980 Flow Data

Glenmore Dike Assessment  Hydrology – Design Flow Rate Determination Estimated Future Precipitation Change Due to Climate Change for the Strathcona Regional District (Data from PCIC’s Plan2Adapt Online Tool)  Statistical Analysis of ~40 years river flow data  Q200 = 493 m 3 /s  Climate Change Impact  Precipitation Increase to 2090 = 15%  Design Flow Rate = 567 m 3 /s (200-Year Return Period Flow, plus Climate Change)

Glenmore Dike Assessment  2-D Hydraulic Modelling using HEC-RAS software (see videos)

Glenmore Dike Assessment  Hydraulic Modelling Findings Matches Observations from December  2014 “Emergency Dike Repair” & Validates Need for Repair

Glenmore Dike Assessment Upgrade Options: (in order of priority)  Priority 1: Maintenance & Repairs  Vegetation Clearing & Replacement of ex. Culvert (incl. new Flap-Gate Chamber)  Est. Cost = $138k (plus $7,000 annual maintenance)  Priority 2: Upgrade & Raise Dike at North End  Upgrade the “emergency repair” section to proper dike standard (approx. 90 meters of dike length to be re-built)  Est. Cost = $303k  Priority 3: Dike Re-build for Long-Term Seismic Stability  In order to completely upgrade the dike to be seismically stable, approximately 510 meters (in addition to the 90 meters from Priority 2) would be re-built.  Est. Cost = $3.775M

Glenmore Dike Assessment Project Successes:  Many dike assessments are done piecemeal. However- concurrent, multi-disciplinary assessments (Condition, Geotech, Hydraulics) led to efficiency in upgrade recommendations based on the sum of all findings, for example:  Culvert replacement, requiring local dike re-construction;  Area around culvert was identified as seismically unstable;  Extend extents of dike re-construction around culvert to improve seismic stability;  Hydraulic assessment determined dike crest could actually be lowered at this location, leading to savings compared to re-build to existing height.  Budget  Budget cap was determined by grant funding. SRD scope in their RFP included condition & geotechnical assessment.  We felt there was sufficient funding to complete additional hydraulic / hydrologic assessment, and all works were completed on-time and within budget.

Thank You McElhanney Consulting Services Ltd. 1307 Shoppers Row Campbell River, BC Contact: Eric Heel, P.Eng. 250-287-7799 Email: eheel@mcelhanney.com