KNL Lands Proposed Drainage Diversion to the Kizell Municipal Drain, City of Ottawa, Kanata North Ward

Transcription

1 KNL Lands Proposed Drainage Diversion to the Kizell Municipal Drain, City of Ottawa, Kanata North Ward Drainage Act, RSO 1990 Chapter D. 17, Section 65 Prepared for: City of Ottawa Prepared by: Stantec Consulting Ltd.

2 Sign-off Sheet This document entitled KNL Lands Proposed Drainage Diversion to the Kizell Municipal Drain, City of Ottawa, Kanata North Ward was prepared by Stantec Consulting Ltd. ( Stantec ) for the account of City of Ottawa (the Client ). Any reliance on this document by any third party is strictly prohibited. The material in it reflects Stantec s professional judgment in light of the scope, schedule and other limitations stated in the document and in the contract between Stantec and the Client. The opinions in the document are based on conditions and information existing at the time the document was published and do not take into account any subsequent changes. In preparing the document, Stantec did not verify information supplied to it by others. Any use which a third party makes of this document is the responsibility of such third party. Such third party agrees that Stantec shall not be responsible for costs or damages of any kind, if any, suffered by it or any other third party as a result of decisions made or actions taken based on this document. Prepared by John van Gaal, P.Eng. (Signature) Reviewed by Matthew Ford, P.Eng. (Signature)

3 Table of Contents 1.0 INTRODUCTION DESCRIPTION OF PROPOSED ADDITIONAL CONNECTION JUST PROPORTION OF DRAINAGE WORKS SUFFICIENT OUTLET FOR THE ADDITIONAL CONNECTION RECOMMENDATIONS LIST OF FIGURES Figure 1 - Key Plan LIST OF APPENDICES APPENDIX A EXAMINATION OF THE KIZELL DRAIN & PRIVATE WATERCOURSES (JUNE 11 AND 22, 2015)... A.1 APPENDIX B OBSERVED IMPEDIMENTS WITHIN THE EXISTING KIZELL DRAIN & PRIVATE WATERCOURSES... B.1

4 1.0 INTRODUCTION KNL Development Inc. being the owner of lands of Lots 7 and 8 Concession 2 and 3 Township of March, City of Kanata (now City of Ottawa), requests the divergence of approximately 150 ha of drainage area from the upper end of the Shirley s Brook watershed into the Kizell Drain watershed. See Figure 1 for Key Plan. KNL Development Inc. delayed proceeding with this proposal, pending completion of the Shirley s Brook and Watts Creek SWM study. With the completion of this report, KNL will want to proceed with the registration of KNL Phases 7, 8 and 9 and subsequently resolve all the outstanding issues pertaining to the proposed diversion. One of those issues will be to update the Engineers Report for the Kizell Municipal Drain. The Township of March adopted the Kizell Municipal Drain pursuant to the Drainage Act under By-law in The original Engineer s report was superseded by a report on the improvement of the Kizell Municipal Drain under the Drainage Act 1970 as presented to the Township of March in April 1973 under By-law It is noted that, Shirley s Brook is a natural watercourse, with no status under the Drainage Act. 1.1 DESCRIPTION OF PROPOSED ADDITIONAL CONNECTION It is proposed that runoff from some of the proponents lands within the headwaters of Shirley s Brook (Kanata Lakes North) be diverted into the Kizell Municipal Drain. Accordingly, KNL have elected to request the City to proceed with a revision to the above noted Municipal Drain in accordance with section 65(3) 1 of the Drainage Act. As part of the KNL Development Inc., a Master Drainage Plan (MDP) storm outlet is to be constructed along the south and east property limits of the KNL lands with an outlet to the Beaver Pond. The Beaver Pond outlets into an urban water course on private property and then into the Kizell Municipal Drain. Provided the diversion has no technical impact on the existing drainage works, the current Drain Bylaw can be updated under Section 65 of the Act. 1 Under Section 65(3) of the Drainage Act, If an owner of land that is not assessed for a drainage works subsequently connects the land with the drainage works for the purpose of drainage or if the nature and extent of use of a drainage works by land assessed for the drainage works is subsequently altered, the Clerk of the local municipality in which the land is situate shall instruct an Engineer, in writing to inspect the land and assess it for a just proportion of the drainage works, taking into account any compensation paid to the owner of the land in respect of the drainage works. sl \\cd1218-f02\01-634\active\1634_01251\planning\report\rpt_kizell_drain_due_diligence_review_ en.docx 1.1

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6 1.2 JUST PROPORTION OF DRAINAGE WORKS Within Section 65 of the Drainage Act, the engineer shall make an inspection and assess the land for a just proportion of the drainage works. While there is no direction within the Drainage Act on what the just proportion should be, it is our opinion that landowners that connect to the Municipal Drain should have to pay an amount of money proportional to their land area (150 ha) in relation to the new total drainage area (i.e. 930 ha plus 150 ha equals 1080ha). Updating the original construction cost of the drainage works using Bank of Canada inflation factors 2 is as follows: Description Year Construction Inflation Total Cost cost Factor (2015 $) Original Drain 1964 $6, $52,100 Twp. of March Bylaw Improvement 1973 $10, $58,800 Twp. of March Bylaw Total $110,900 Notwithstanding the concern with insufficient outlet for the added connection, KNL Development Inc. s just proportion for connecting to the Municipal Drain would be 14% of $110,900 or $15,526. Within Section 65 of the Drainage Act, it indicates that the monies collected shall be credited to the account of the drainage works and shall be used only for improvement, maintenance or repair of the whole of any part of the drainage works. As a result, the monies collected could be used for future maintenance of the drain. 1.3 SUFFICIENT OUTLET FOR THE ADDITIONAL CONNECTION The 1973 Engineers report and plans, describes the Kizell Municipal Drain as commencing from the twin culverts under the CNR tracks upstream to the Highway 17 box culvert (now Carling Ave). It then continues in a north westerly direction to the Boundary Road between March/Nepean Townships (now Hertzberg Road) then continuing north westerly ending at Legget Drive. Upstream of this point the drain has no status under the Drainage Act. 2 Inflation Factor computed based on Bank of Canada inflation Calculator sl \\cd1218-f02\01-634\active\1634_01251\planning\report\rpt_kizell_drain_due_diligence_review_ en.docx 1.3

7 I have examined the Municipal Drain portion from Legget Drive downstream to the CNR culverts and the non-municipal drain reach from the Beaver Pond to Leggett Drive (see Appendix A). Based on an examination of the drain, and a review of the findings from the Shirley s Brook and Watts Creek SWM Study 3, it is our opinion that the Kizell Drain does not currently have sufficient capacity for the proposed additional connection from KNL for the following reasons: 1. The drain has erosion of its banks and the additional volume of water from the proposed connection will aggravate existing erosion conditions and downstream sedimentation problems. 2. The Shirley s Brook and Watts Creek SWM Study identified 2 flood vulnerable buildings on the Kizell Drain between Herzberg Road and Legget Drive, upstream of March Road on the Nordion campus. Any increase in flow rate and change in water levels will increase flood risks to these buildings. 3. The Shirley s Brook and Watts Creek SWM Study identified the March Road sewage pumping station on Legget Drive as a flood vulnerable structure (i.e. Building floor elevation is 74.0 m.a.s.l. and the 100year flood level is 75.0 m.a.s.l.). Under a flood scenario, a sewage pump station shut down may be required. Current flow rates and water levels are concerning and any changes to the channel may heighten this concern. 4. The Legget Drive culvert is noted to have a 1:5 year return period level of service whereas City Design Guidelines call for a 1:25 year return period. Any change in channel hydraulics may heighten this concern. 5. The Shirley s Brook and Watts Creek SWM Study identified 2 flood vulnerable buildings on the Kizell Drain and upstream of March Road on the Nordion campus. Any increase in flows and change in water levels will increase flood risks to these buildings. 1.4 RECOMMENDATIONS Regardless of whether the diversion proceeds or not, improvements to the Drain are recommended (see Section 1.3 and Appendix B). The design of these improvements could be made such that there is sufficient capacity to include the additional flow from the requested diversion, however the existing 1973 Engineers report does not allow for this type of improvement. To expedite the required drain improvements within the Municipal Drain, the recommended course of action is to extend Municipal Drain status 3 Shirley s Brook and Watts Creek Stormwater Management Study Phase 2 by AECOM Final- April 27 th sl \\cd1218-f02\01-634\active\1634_01251\planning\report\rpt_kizell_drain_due_diligence_review_ en.docx 1.4

8 upstream to the Beaver Pond. Under this scenario, required drainage works can be adequately determined and engineered, costs are recovered from the landowners within the drain, and access to the drain including a working space width is included in the Engineers report to allow for future maintenance & repair. To initiate work on a new Municipal Drain (i.e. from the Beaver Pond to the downstream crossing of Legget Drive) will require a signed Petition under Section 4 of the Drainage Act. To validate this petition, signatures from KNL Development Inc., MDS Nordion, the NCC and if required the City of Ottawa Road Manager, and other landowner are recommended. It is noted that, the requested diversion from Shirley s Brook to the Kizell Drain has been reviewed from the viewpoint of the Kizell Drain. The impact of the diversion on Shirley s Brook, does not form part of this review. Also, the Ministry of the Environment and Climate Change will require that an Environmental Compliance Approval (ECA) be obtained, since the watercourse will be considered as conveying sewage and is not exempt due to the urban land-use of the tributary lands. sl \\cd1218-f02\01-634\active\1634_01251\planning\report\rpt_kizell_drain_due_diligence_review_ en.docx 1.5

9 Appendix A Examination of the Kizell Drain & Private Watercourses (June 11 and 22, 2015) Review of road crossings from a hydraulic capacity point of view. a. Twin culverts at CNR. Note the Shirley Brook and Watts Creek Study refer to this location as a 2,500 mm diam. culvert. The Kizell Drain notes them to be Two 2,100 mm diam. (7 ft.) concrete culverts. b. Carling Ave culvert is a 4,800 mm by 1,200 mm box at invert 71.5 m (report invert 71.7 m). The upstream end appears to be submerged. The Carling Ave culvert and road constriction causes a 0.5 m back water to elevation m. (No picture provided). A.1

10 c. Hertzberg Road Culvert is a 3,000 mm by 2,000 mm box at invert 72.1 m (report invert 72.2 m). Road and culvert constriction causes a 0.25 m backwater to elevation 74.8m. Crossing does not offer sufficient freeboard but is acceptable from a capacity point of view. A.2

11 d. Legget Drive (D/S) has insufficient capacity and freeboard per City standards. e. Legget Drive (U/S) has insufficient freeboard but is acceptable from a capacity point of view. A.3

12 f. A 1,200mm diam. culvert upstream of March Rd, discharges into a 2,500mm by 1,500mm box culvert under March Rd. The 1,200mm inlet control culvert is a significant hydraulic constraint and affects upstream water levels by as much as 2 m during a 100 year event. This culvert is structurally deficient and could fail as illustrated in second photograph. A.4

13 g. By restricting flow rates and causing upstream flooding, the 1200 mm diam. culvert impacts the Nordion campus land uses. The 100 year flood lines are shown to encroach onto the parking areas, cut off building access and directly affect 2 campus buildings. In the picture below, 100 year flood level are as much as 2 m above the top of bank. A.5

14 Appendix B Observed Impediments within the Existing Kizell Drain & Private Watercourses Observed impediments within the existing drain are described below. The 1973 Drainage report requires an update as follows: a. Show current drain alignment (i.e. Lot 6 Conc. IV upstream of Legget Drive). b. Show flood protection berm and pump station on development lands south of Legget Drive. c. Cross section is no longer applicable. The channel bottom has widened beyond 2.4 m (8 ft.) and the channel banks are steeper than 2:1. Watts Creek upstream of CNR d. The Drain needs to be maintained and cleaned to improve hydraulics. e. Update assessment schedule per the current land ownership and watershed land uses. B.1

15 Kizell Drain between Carling and Hertzberg f. Hydraulic redesign to account for the current watershed land uses and increased flow rate. g. Add a working space for future maintenance of the drain. B.2