Mayor and Council Tony Seibert, Drainage Engineer Waechter Creek Culvert Emergency Repair at Simpson Road Extension

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Kristian Griffith
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1 SS 1~A ABBOTSFORD Report No. ENG COUNCIL REPORT Regular Committee March 14,2014 File No: To: From: Subject: Mayor and Council Tony Seibert, Drainage Engineer Waechter Creek Culvert Emergency Repair at Simpson Road Extension RECOMMENDATIONS 1. THAT the proposed Waechter Creek Culvert Emergency Repair budget be approved in amount of $750,000; 2. THAT the $450,000 project shortfall in the current capital plan be funded from the General Capital Reserves; 3. THAT work be awarded to Strohmaier's Excavating Ltd. in the amount of $589,200; and 4. THAT the Mayor and Corporate Officer be authorized to execute all documents related to this matter. SUMMARY OF THE ISSUE A portion of the culvert at Waechter Creek has collapsed. Emergency repair IS recommended as there is significant potential for further collapse, which will lead to upstream property flooding, potential washout of 22m high fill embankment and the sanitary sewer trunk main within it, negative impact on FortisBC gas lines and downstream environmentally-sensitive habitat. This report discusses the background of the issue and recommends next steps. BACKGROUND The City has a 106m long, 1050 x 900mm oval reinforced concrete culvert that is set in Waechter Creek (Culvert), near the east end of Simpson Road Extension (see Attachment A - for Location Map). This Culvert was originally installed in early 1900s to allow the railway to build an embankment 22m high across a small valley and convey the creek flows (1: 1 00 year event). The City acquired the property and associated liabilities in In 1979, the City installed a 600mm diameter reinforced concrete sanitary trunk main across the old railway alignment to take advantage of the suitable grades for gravity flow. This trunk main runs near the top of the old railroad grade, generally perpendicular to the Waechter Creek Culvert. The sanitary main conveys a large area, including; West Abbotsford, Pepin Brook and Sun Valley Developments. In late 2013, the Culvert was inspected using a robotic camera. The results indicated that the entire length of Culvert is in structurally poor condition, with a 5m section partially (50%) collapsed. The collapse is most likely due to the age of the pipe, the height of the fill, large trees growing in the fill over the Culvert and a potential loss of bedding due to groundwater and/or surface water carrying fine soils away.

2 Report No. ENG Page 2 of 3 High pressure distribution gas mains (Fortis BC) are located 75m south of the culvert. In addition, the Creek is environmentally sensitive fish habitat. The Culvert needs to be repaired as soon as possible as there is significant potential for further collapse. The present (and any future) blockages of flow have potential to cause flooding of upstream property, washout the fill and the sanitary sewer mainline within it and negatively impact the FortisBC gas lines and environmentally-sensitive habitat (see Attachment B - for a summary of site challenges). DISCUSSION Seven contractors were asked through a December 29, 2013 Request for Response (RFR) to propose a design build solution to the failing culvert. The firms invited have successfully completed previous work with similar challenges, are considered specialists in this type of work, have positive references and completed similar emergency repair work for the City in the past. Three responses were received on January 23, The summary of responses is as follows: Proponent Point Repair m Complete Repair - 106m (excluding tax) (excluding tax) Strohmaier's Excavating Ltd $283,171 (permanent) $589,200 PW Trenchless Construction Inc. $239,915 (temporary) $681,775* Sandpiper Contracting LLP $980,000 n/a *Not Including bypass pump operating costs Clarifications and revisions to reflect site conditions were requested after the RFR closed. Further information was received from Strohmaier's and PW Trenchless on their responses. Adjustments were made to the prices as a result of the clarifications, which are reflected in the above prices. The Responses were evaluated in relation to standard criteria by a three member evaluation team. Strohmaier's Excavating Ltd. ranked the highest as they can meet the project technical requirements, including environmental, scheduling and access and they provided a competitive-priced response, with least risk in comparison to the other responses. Given that the entire length of the Culvert is in poor condition, and the lower per meter rate to replace the whole Culvert (approximately $5,660/m versus $13,800/m for partial repair), it is recommended that complete repair of the Culvert be undertaken. Based on the review team's evaluation, it is recommended that the proposed Waechter Creek Culvert Repair work be awarded to Strohmaier's Excavating Ltd. in the amount of $589,200. The work will replace the existing culvert with a new culvert with an expected 100 year life cycle. The scope of work includes temporary Creek by-pass using a horizontally directional drilled 300mm diameter high density polyethylene (HOPE) pipe, and to pipe jack and burst a new 1050mm diameter steel culvert in place of the existing concrete culvert for the full 106m length. Pipe bursting is a trenchless replacement method in which an existing pipe is split, using an internal bursting tool. At the same time, a new pipe is pushed through the existing pipe. It is anticipated that the project will commence immediately following a!;>signment award in the week of April 14, The project duration is approximately 3.5 months, with anticipated completion by early August 2014.

3 Page 3 of 3 FINANCIAL PLAN IMPLICATION The total project cost is estimated at $750,000 including the proposed Culvert Repair work of $589,200 (Attachment C - Cost Summary). The 2014 capital plan currently includes $300,000 for this project, funded from the General Capital Reserve. Sufficient funding is available to supply the additional $450,000 required from the General Capital Reserve. ~ ' f1 \ \ ~ Reviewed and approved by the: Chief Financial Officer IMPACTS ON COUNCIL POLICIES, STRATEGIC PLAN ANDIOR COUNCIL DIRECTION The new Culvert replacing aging infrastructure will reduce flood and/or washout potential due to collapsing pipe and reduce potential for flood damage to City sanitary sewer main servicing west Abbotsford, residential properties, farmlands and downstream environment. The proposed project is directly related to Strategic Objective #1 Continue Improving our Financial Outlook. SUBSTANTIATION OF RECOMMENDATION In November 2013, the entire length of the Waechter Creek Culvert was discovered to be in poor condition, with a portion partially (50%) collapsed. The Culvert needs to be repaired as soon as possible as there is significant potential for further collapse. Blockage of flow will flood upstream property, potentially washing out the fill and the sanitary sewer mainline within it, which will also negatively impact the FortisBC gas lines and environmentally-sensitive fish habitat. A design-build proposal from Strohmaier's Excavating Ltd. to replace the entire Culvert with steel pipe at this location by using a pipe bursting process is recommended as the most economical and least risk option. It is recommended that the proposed Waechter Creek Culvert Emergency Repair budget be approved in amount of $750,000; funded from the General Capital Reserves; and that the proposed Waechter Creek Culvert Repair work be awarded to Strohmaier's Excavating Ltd. in the amount of $589,200. The project is to be completed by early August Prepared; Tony Seibert, P. Eng.. Drainage Engineer rtment Head Approval: Gordon, P. Eng. General Manager, Engineering and Regional Utilities Attachment "A": Waechter Creek Culvert Location Map Attachment "B": Site Challenges Attachment "C": Cost Summary TS/sv

4 ATTACHMENT A ~~~.A ABBOTSFORD Waechter Creek Culvert Location

5 ENG Attachment B - Project Challenges The project is challenging due to: Risk of further culvert failure - Due to the need for Emergency repair and to expedite the repair the RFR was sent to knowledgeable contractors with expertise in this type of work, and was not advertised on BC Bid "electronic tendering system". The New West Partnership Trade Agreement conditions do not apply in circumstances meeting the exception, specifically: "C. 2. (h) where an unforeseeable situation of urgency exists and the goods, services or construction could not be obtained in time by means of open procurement procedures;" Limited access - the culvert is at the bottom of a 22m high fill with steep banks, and old growth forest cover; FortisBC ROW -high pressure distribution main lines are located south of the fill; Private property to the north, south and east; Environmental - the Creek is salmon habitat, downstream are Nooksack Dase (SARA) and Salish Sucker habitat (SARA), and the area is prime Oregon Snail habitat (SARA), and old growth forest cover; Sanitary sewer /s flows, this pipe must not be disturbed and a failure could introduce untreated sanitary effluent into Waechter Creek; Waechter Creek - base-flow must be maintained at all times, and there is no easy route to divert the creek flow around the fill. Limited Construction and rehabilitation methodologies due to the depth of the culvert and the close proximity of the sanitary and high pressure distribution gas mains open cut construction method was deemed not a feasible choice. Trenchless pipe bursting and pipe jacking was deemed the most feasible methodology. Due to the size of culvert, the depth of fill and the proximity of surrounding infrastructure the methodology recommended is complex and includes risk.

6 ENG Attachment C - Cost Summary Waechter Creek Culvert Repair at Simpson Road Extension Item Description Cost Estimate 1.0 Contractor Bypass and Pipe Bursting $589, Environmental Applications, Approvals & Monitoring $9, Survey Topographic Survey & Base Map $3, Geotechnical Preliminary Investigation & Report $3, Access Agreement Temporary Working ROW & Staging $25,000 Area Preparation 6.0 Utility Sanitary & Storm Emergency back-up plans in place $25, Provisional Bypass Pumping - in the event gravity $28,000 system is not achievable 8.0 Contingency Construction Contingency $66,800 Total Cost $750,000 Details of Items 1 to 6 are described below: 1.0 Contractor Details are discussed in this Council Report ENG Environmental Approvals and Monitoring Waechter Creek is important fish habitat and the installation of a new culvert will require environmental approvals. AquaTerra provided the initial inspection and emergency notification for the site in November Staff requested a proposal from AquaTerra to complete the Environmental Approvals and Monitoring for this project because of their expertise, previous experience with Waechter Creek, competitive rates on recent proposals; and good working relationship with staff. Staff reviewed the AquaTerra proposal and considers it reasonable. The proposal is estimated $9, Topographic Survey and Base Mapping - completed by the City Surveying Department. Cost for this work $3,500.

7 ENG Attachment C - Cost Summary 4.0 Geotechnical Investigations - Due to time constraints and a need to provide the contractors with basic soil conditions, proposals were requested from two consultants, and Western Geotechnical was selected based on schedule, experience, and fees in amount $3,500. The Geotechnical Report was issued December 18, Access The City has an existing sanitary sewer right-of-way (ROW) off Mt Lehman that will be utilized to provide access to the site for material and equipment. Our Senior Property Negotiator has secured two Temporary working ROW agreements. The temporary working ROWs will provide working areas at the inlet and outlet of the culvert. There is some clearing required within the City ROW to provide a staging area for the contractor to unload, load and store material and equipment Estimated cost for preparing the staging area and negotiating ROW agreements is $25, Back up Planning - The City Waste Water Collection Department will make provision and have emergency bypass in place and ready to go (including material, equipment and staff) into operation in the event there is a leak or break in the sanitary sewer pipe during the critical construction period (when culvert is being replaced). Based on previous City experience with bypass pumping, the cost for the emergency sanitary by-pass plan is estimated to be $20,000. It is recommended that this back up plan be implemented by City staff with an estimated cost in the amount of $25, Provisional - The Contractor plans to install a 300mm HOPE pipe with suitable elevation and grades to allow for Waechter Creek to be diverted with gravity flow. However the 300mm HOPE pipe will have to be installed at the boundary layer between the native soils (clay) and the fill (pit-run), where there is potential to be fallen trees or tree roots left from time of construction of the railway fill. The initial test pit did show some wood at this boundary layer, and it is recommended that we plan for the possibility that the installation will not go in with a perfect alignment to allow for gravity flow - we will then need to bypass pump for the 10 days of actual bursting of the pipe. This cost is estimated to be $28,000 as provided by Strohmaier's Excavating Ltd.

Preliminary Design Report: Prices Subdivision Drainage Improvements & Wastewater Servicing

B.5.1 Preliminary Design Report: Prices Subdivision Drainage Improvements & Wastewater Servicing --Greenland Consulting Engineers-- 1 The Study Location (Prices Subdivision) consists of the lots fronting