HomeMy WebLinkAboutStanley Consultants - Supplemental Agmnt #1 - Upton Ave Detention Basin - 8/19/19SUPPLEMENTAL AGREEMENT NO. 1
This Supplemental Agreement, made and entered into by and between STANLEY CONSULTANTS, INC. (Consultant)
and CITY OF WATERLOO (Client) amends their agreement of April 16, 2019, for Consultant to provide services to
the Client for the Upton Stormwater Detention Project, as follows:
Scope of Services
The "hybrid" alternative design, which includes two on-site stormwater detention ponds, was chosen to be carried
forward into detailed design by the Client and includes re-routing of stormwater runoff from the Upton Avenue
watershed to the Greenhill Road drainage system via an underground pipe. The additional work includes:
1. Review of the existing Greenhill Road storm sewer line at the location of the proposed connection to the ultimate
outfall. Determine the existing drainage areas contributing runoff to the storm sewer.
2. Analyze the Greenhill Road storm sewer capacity, which is assumed to be a 10 -year event, relative to the amount
of stormwater being re-routed from Upton Avenue during the design rainfall event (100 -year). Upton detention
release rate will be added to the Greenhill Road storm sewer to check the effect on capacity at the assumed 10 -
year event and one other event to be determined during the analysis. The analysis will be performed using
available storm sewer utility information provided by the Client, as well as with the HydroCAD model developed
by Consultant for the "hybrid" alternative design. Once complete, the analysis will show whether additional flows
into the Greenhill Road storm sewer system significantly increase the risk of flooding in and around the areas that
drain to it, or if the proposed design is able to adequately convey stormwater runoff into and through the Greenhill
Road storm sewer. Add results to Upton Study Addendum.
3. Conference call to review results.
Time of Beginning and Completion
August 12, 2019 to December 31, 2019
Fees and Payments
$ 6,800
Except as specifically amended by this Supplemental Agreement,
Agreement dated April 16, 2019 shall remain in full force and effect.
IN WITNESS WHEREOF, the parties have caused this Supplemental
indicated.
all the terms
Agreement to
STANLEY CONSULTANTS, INC. CITY OF WATERLOO
Bv:
Date: August 13, 2019
Attest:
By:
28760.02.00 Upton Stormwater Detention Project
SC3881 1014
By:
Date -
Attest:
By:
'GL1C�
and conditions
be executed on
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of the original
the date below