Elena Caruso Acting Director

Purchasing and Materials Management Division City Hall, 18th Floor, West Tower 100 Queen Street West Toronto, Ontario M5H 2N2

Victor Tryl Manager Professional Services

November 7, 2014 Posted in PDF (6 pages)

ADDENDUM NO. 1 REQUEST FOR PROPOSAL NO. 9117-14-7256

CLOSING: 12:00 NOON (LOCAL TIME), DECEMBER 9, 2014

For: BASEMENT FLOODING REMEDIATION AND WATER QUALITY IMPROVEMENT MASTER PLAN CLASS ENVIRONMENTAL ASSESSMENT (EA) STUDIES – STUDY

AREAS 34 to 41

Please refer to the above Request for Proposal (RFP) document in your possession and be advised of the following: I. Additions

1. The attached " Benefiting Homes Calculation Guideline" is added to the RFP as Appendix G

II. Questions and Answers Q1: Will the proponent be precluded from bidding, and if successful working on both this BF

Remediation and Water Quality Master Plan, and the Basement Flooding Protection Program Phase 4 assignments?

A1: Proponents wishing to submit proposals for both RFP 9117-14-7256 and RFP 9117-14-7110 can

do so. Any successful proponent(s) for RFP 9117-14-7256 will not be precluded from being awarded/considered for RFP 9117-14-7110 and vice-versa.

Should you have any questions regarding this addendum contact Allison Phillips at aphilli2@toronto.ca or 416-397-4825. Please attach this addendum to your RFP document and be governed accordingly. Proponents must acknowledge receipt of all addenda in their Proposal in the space provided on the Proposal Submission Form as per Appendix C, Section 4 - Addenda of the RFP document. All other aspects of the RFP remain the same. Victor Tryl Manager Professional Services

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Benefitting Homes Calculation Guideline

Definition:

• The number of upstream homes that move from not meeting the City’s Basement Flooding Protection Program criteria to meeting the BFPP criteria with the construction of recommended upgrades.

• The BFPP criteria includes; – 1.8 m HGL clearance for storm and combined sewers during a 100 year

storm event. – 1.8 m HGL clearance for sanitary sewers under the May 12, 2000 storm

event. – No surcharge for shallow sewers with obvert less than 1.8 m below

ground surface. – Maximum surface ponding depth not to exceed 150 mm above the crown

of the road; for arterial roads, one lane must be free of water in each direction up to the 100-year storm.

Note that the base condition to estimate number of benefitting homes from should be post 75% roof downspout disconnection. Methodologies:

• Benefitting homes are calculated upstream of recommended upgrade works. • The inclusion of homes downstream of recommended works (e.g. in the case of

storage project) would be considered an exception to the rule. • All exceptions must be documented by the EA consultant on a project by project

basis including a rationale for the exception, and the altered calculation methodology. This will ensure transparency and repeatability.

• Benefitting homes cannot be double counted. The sum of benefitting homes from individual projects cannot exceed the total number of benefitting homes within a Study Area.

• In cases where it can be difficult to define which homes benefit from which project, bundling should be used to simplify this question. To this end, the goal is to create viable project bundles. Bundled projects must be hydraulically linked. For example, If there is an end-of-pipe project near an outfall, than the whole area is hydraulically linked, and the gaps between individual components should be less than 250 m.

• Partial calculations should not be undertaken. If at least one manhole on a sewer reach (upstream or downstream manhole) does not meet the City’s criteria, then all homes within that sewer reach shall be considered as benefitting.

• Keep in mind that the goal of this methodology is to provide a ranking tool that

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is simple, and that can be easily applied across the city. It has not been designed to accurately determine the number of benefitting homes for each project. On average, with sometimes over counting and sometimes undercounting by small amounts, the approach should achieve the objective for the ranking of projects. The goal is to construct all works in a fair and ordered way. The tool is not meant to say that projects will never proceed.

• All benefitting home calculation values, assumptions and exceptions, should be contained in a supplemental document for internal use only. It should not be contained within the Project File for the EA study.

Sample: Figure 1 - Minor system modelling results Figure 1 shows the minor system results for the base condition under the design storm event. Assuming that a proposed project could theoretically eliminate the BF risks illustrated, homes that can be considered as benefitting from such a project are within the outline. The general rule of thumb is that if a node is not satisfying the BF HGL criteria (i.e. <1.8m depth) under the base condition, then all houses that could be connected to the sewers upstream and downstream of that node are considered benefitting from the mitigating project. There are a few additional items to consider. For example, Houses A and C on Figure 1 can be considered to be "connected" or "not connected" to a sub-standard sewer under the base condition, and could therefore be considered as "benefitting" or "not benefitting" from the project. Also, House B fronts the street on the left and is therefore assumed to be connected to the sewer on that street, which satisfies the BF HGL criteria. Therefore, House B is not benefitting from the project. Where data is available, City will provide a shapefile linking each address to a specific sewer segment to identify which sewer the house connects to. Figure 2 - Major system modelling results Figure 2 shows the major system results for the base condition under the design storm event. Assuming that a proposed project could theoretically eliminate the BF risks illustrated, homes that can be considered as benefitting from such a project are within the outline. The general rule of thumb is that if a node is not satisfying the BF major system depth criteria under the base condition, then all houses that are adjacent to the major system flow paths upstream and downstream to that node are considered benefitting from the

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mitigating project. Figure 3 - Overlap of properties receiving storm and sanitary benefits from same project Figure 3 shows a situation where the same project includes both storm and sanitary improvements, each with different benefitting areas that overlap. The assumption has been that any property that a project benefits counts only as 1 benefitting home, even when such project eliminates both storm and sanitary related risks for that property. The reasoning is that the objective is to identify the quantity of homes benefitted by a project, not the number of times each home is benefitted by a project. As such, the number of benefitting homes where there is an overlap = #STM + #SAN – overlap.

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