The Corporation of Delta COUNCIL REPORT Regular Meeting To: Mayor and Council File No.: 5140-20/BBSB From: Engineering Department Date: October 28, 2016 Boundary Bay Temporary Flood Protection Works The following report has been reviewed and endorsed by the Chief Administrative Officer. RECOMMENDATION: THAT this report be received for information. ------------- PURPOSE: The purpose of this report is to provide Council with an update on annual storm preparedness activities in Boundary Bay Village and Beach Grove, as well as present long term weather predictions for the upcoming winter storm season. BACKGROUND: Every fall, staff carry out flood preparedness activities in Boundary Bay Village and Beach Grove, in an effort to minimize potential damage caused by significant southeasterly winter storms. At the May 16, 2016 Regular Meeting, Council adopted a recommendation to extend the temporary sand berm to include protection between 3 Avenue and 4 Avenue. DISCUSSION: Temporary Flood Protection Works Temporary flood protection works at select locations in Boundary Bay Village and Beach Grove have been carried out annually since the 1970s. The works primarily entail constructing a berm fronting a number of private residential properties in the 200 block of Centennial Parkway, where no seawalls exist. This year the sand berm was also extended north fronting the 300 block of Centennial Parkway (see Attachment A), due to flooding that occurred in March of this year. In addition, the 16 Avenue beach access and all beach access points south of 4 Avenue are secured with concrete blocks and/or sand bags. The blocks are placed with a passage gap to allow continued pedestrian access to the beach, and stockpiles of sand and sand bags are provided to facilitate blocking the access should the necessity arise. Signs are posted at each affected
Page 2 of 3 Boundary Bay Temporary Flood Protection Works 5140-20/BB8B October 28, 2016 access point notifying the public of temporary flood protection measures. This year's work was completed several weeks earlier than in previous years in anticipation of a major storm system in mid October. A copy of the "Activation of the Plan" section from the Staged Flood Preparedness and Response Plan - Beach Grove and Boundary Bay Vii/age is provided as Attachment B for reference. Storm Surge Almanac for BC Flood risk to the communities of Boundary Bay Village and Beach Grove is highest during the seasonal perigean spring tides (king tides), which occur during the summer and winter solstices. During this period tides reach,,or slightly exceed, 5.0 metres at Point Atkinson. This year's spring tides for the Lower Mainland are expected near the middle of November, December and January. A calendar indicating specific days with tides over 4.7 and 4.9 metres at Point Atkinson is provided as Attachment C. The major EI Nino of 2015/2016 is gradually dissipating and conditions are trending towards an EI Nino/Southern Oscillation neutral condition. EI Nino/Southern Oscillation models are indicating that a La Nina condition may develop in the short term, followed by an EI Nino condition in early 2017. Although the emerging La Nina conditions could bring a late-season change to the already experienced strong storms this fall, past similar changes from a strong EI Nino condition to a La Nina condition have varied from stormy wet conditions well into spring to very cold predominantly high-pressure conditions. Due to this uncertainty, monitoring is imperative to ensure preparedness. Implications: Financial Implications - The expenditure for the Boundary Bay sand berm and associated works this year is approximately $50,000, including disassembly, and is included in Engineering's Operation Budget. CONCLUSION: Installation of annual temporary flood protection works was completed the week of October 10, 2016, almost a month earlier than previous years due to an impending storm event. For the Lower Mainland, the highest tides will occur in mid November, December and January. Staff, in coordination with Delta's Emergency Coordinator, will be monitoring peak tides, predicted storm surge and weather forecasts throughout the winter months in an effort to be well informed in advance of potentially high risk storm Steven Lan, P.Eng. Director of Engineering Department submission prepared by: Harald Fograscher, P.Eng., Manager of Utilities HCF/sa/1i
f: 'I ;1 lj,: ;l r~ t~ I. Page 3 of 3 80undary 8ay Temporary Flood Protection Works 5140-20/88S8 October 28,2016 f "!! 1 This report has been prepared in consultation with the following listed departments, Concurring Departments Department Name Signature Finance ATTACHMENTS: l / Karl Preuss I~ A. Sand Berm Photographs B, Staged Flood Preparedness and Response Plan - Beach Grove and Boundary Bay Village ' C, High Tide Calendar for Point Atkinson ~ I'llI' ( (101 r,11 J ) 1 l (J ", I '"'I '..
Sand Berm Photographs Attachment A Page 1 of 1 Looking South from 3 Avenue Looking North from 3 Avenue
Staged Flood Preparedness Plan Boundary Bay/Beach Grove Attachment B Page 1 of2 October 19, 2011 Stage 1 - Standard Response (November through March) 1. Temporary flood protection construction and placement of concrete blocks at beach access points. 2. Strategic placement of sand piles (single tandem loads) and sand bags at the following locations: III Seaview Road, III 1A Avenue boat launch, III 3 rd Avenue row, and 16 th Avenue row. 3. An additional supply of sand bags will be stored at the works yard for deployment to the sand pile locations under Stage 2. Sand bags will also be available to the public at the works yard during regular hours. 4. Weather forecasts monitored on a continual basis. Stage 2 - Heightened Response (based on tide and weather forecast) Operations staff mobilize with the following activities: 1. Beach access points to be sealed with sand bags, stored on site. 2. Additional bundles of sand bags delivered to sand pile locations, minimum 500 at each location. 3. A generator will be hooked to a tow vehicle and ready for deployment to 1 ih Avenue pump station. 4. As warranted, Changeable Message Sign Boards (CMS) to be located at the following locations: III Intersection of 1 ih Avenue and Boundary Bay Road, Intersection of 16 th Avenue and 57B Street, and III u'tilization of the SO Rec. Centre sign board
Attachment B Page 2 of2 CMS's to read: "STORM WARNING HIGH TIDE ANTICIPATED STRONG S.E. WINDS" 5. Full~time staff member dedicated to monitoring storm effects at the site. 6. Notification of Stage 2 response by email to the following individuals; Mayor, CAO, Department Heads & Fire. Email to be sent by Manager of Operations. 7. Portable drainage pump to be hooked to a tow vehicle and ready for deployment. Stage 3 - Widespread Flooding 1. Implementation of Corporate Emergency Response Plan, including extensive staff callout. END OF PLAN
Attachment C Page 1 of 1 M T w T F 5 5 M T w T F 5 5 1 2 3 4 5 6 1 2 3 4 7 8 9 10 11 12 13 5 6 7 8 9 10 11 ~-~----I 14 15 16 I 19 20 ">- --J 12 13 21 22 23 24 25 26 27 20 21 22 23 24 25 28 29 30 27 28 29 30 31 lii~:'~iij "!"'~, M T w T F 5 5 1 M T W T F 1 2 3 5 5 4 5 2 3 4 5 6 7 8 6 7 8 9 10 11 12 9 10 11 - ~ I --1~ - -- I ----~l, ", I, L _ J -J 13 14 15 16 17 18 19 17 18 19 20 21 22 20 21 22 23 24 25 26 23 24 25 26 27 28 29 27 28 I 30 31 ~, :~ D 4,7-4,8M 4,9 - S.O M Calendar of dates with tides exceeding 4. 7m at Point Atkinson. The peak tides during this four month period occur primarily mid month for November, December and January (S.Om) 1 '