HomeMy WebLinkAbout12. 19-411 JULY 23, 2019 19-411 RESOLUTION
(CARRIED 7-0 LOST LAID OVER WITHDRAWN )
PURPOSE: APPROVE AMENDMENT TO PROFESSIONAL SERVICES
AGREEMENT FOR STORM WATER MANAGEMENT PLAN FOR
GALLUPS / MERRITTS CREEK WATERSHED / BROWN AND
CALDWELL ($13,975.00)
INITIATED BY: DEPARTMENT OF PUBLIC WORKS
BE IT RESOLVED by the Common Council of the City of Oshkosh that the proper
City officials are hereby authorized to enter into and take those steps necessary to
implement an appropriate amendment to the professional services agreement with
Brown and Caldwell for engineering services related to the development of a Storm
Water Management Plan for the Gallups/Merritts Creek Watershed in the amount of
thirteen thousand nine hundred seventy-five dollars ($13,975.00).
Acct. No.0321-0410-6804-049xx Contract Control Fund - Storm Sewer
City
of
Oshkosh
MEMORANDUM
TO: Honorable Mayor and Members of the Common Council
FROM: Justin Gierach, Engineering Division Manager/City Engineer
DATE: July 18, 2019
RE: Approve Amendment to Professional Services Agreement for Storm Water
Management Plan for Gallups/Merritts Creek Watershed/Brown and Caldwell
($13,975)
BACKGROUND
A professional services agreement with Brown and Caldwell for developing a storm water
management plan for the Gallups/Merritts Creek Watershed was approved by the Common
Council on June 9, 2015. During the course of the project, Brown and Caldwell was requested to
analyze the culvert crossing at the southern end of runway 18-36 at Wittman Regional Airport.
ANALYSIS
Wittman Regional Airport is planning to reconstruct Taxiway A and, as a part of the
reconstruction, is planning to replace the existing twin 63" by 87" corrugated metal pipe (CMP)
culverts under the taxiway at the southern end of runway 18-36. The existing twin CMP culverts
under runway 18-36 are not planned for replacement until such time as the runway pavement
requires replacement. The City requested that Brown and Caldwell help analyze the impacts of
changing the culvert capacity with regards to flooding potential upstream and downstream of
the airport.
FISCAL IMPACT
Staff has reviewed the amendment and the proposed costs and has found the costs consistent
with the level of effort that will be expended in order to complete this additional work. The
amount of this amendment is$13,975. This will raise the total agreement amount to$149,163(not
to exceed). Funds for this project are included in the Storm Water section of the 2015 Capital
Improvement Program.
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RECOMMENDATIONS
Chapter 12 of the Municipal Code of the City of Oshkosh provides that professional services of a
specialized nature, including engineering services, may be procured without the use of formal,
sealed quotes. I have reviewed the amendment and in accordance with Section 12-16 of the Code,
I am hereby recommending the Common Council approve this amendment.
Approved,
Mark A. Rohloff
City Manager
JER/tit
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Attachment A
Amendment#2 to Gallups/Merritts Creek Watershed Storm Water Management Plan RECEIVED
Brown and Caldwell Project# 148104
City of Oshkosh Reference: Authorization Date: 6/9/2015 JUN 11, 2019 2l 2019
DEpT
OF u8Ll WOI
This Attachment A documents additional scope and tasks requested of Brown and CaldwelI(Bej•bVyt1tg‘�J l KS
City of Oshkosh(City)for services under the Gallups/Merritts Creek Watershed Storm Water NSIN
Management Plan project(City Authorization Date 6/9/15; BC Project# 148104)agreement dated July 1,
2015.
Scope Changes
Add Task 10 to the scope of work as follows:
Task 10. Analysis of Culvert Crossing at South End of Airport Runway(#18—36)
The Wittman Regional Airport is planning changes to the existing twin 63"x 87"CMPA culverts located
at the south end of Runway#18-36. The airport will be reconstructing Taxiway A and plans to replace
the twin 63"x 87"CMPA culverts.
The airport is considering two pipe sizes,twin 78"RCP or twin 53"x 83"HERCP culverts in the vicinity
of Taxiway A. The existing twin CMPA culverts will not be fully replaced under Runway#18-36 until
the runway pavement requires replacement. The City wants to analyze the impacts of increasing the
existing culvert capacity regarding flooding potential west and east of the airport. Under this new task,
BC will conduct the following work.
10a Revise the existing XPSWMM model to replace the existing twin CMPA to twin 78"
RCP culverts under Taxiway A and Runway#18-36.
10b Revise the existing XPSWMM model to replace the existing twin CMPA to twin 53"x
83" HERCP culverts under Taxiway A and Runway#18-36.
10c Revise the existing XPSWMM model to replace the existing twin CMPA to a 6' x 12'
concrete box culvert. It is anticipated that this will increase peak flow rates and flow
volumes downstream of Wittman Regional Airport. Initial results of the modeling will be
documented and discussed with the City. No further analysis of mitigation measures will
be conducted.
l Od Conceptually resize a dry detention basin to be located west of the twin CMPAs. The
detention basin will be sized to prevent overland discharge north(to the Glatz Creek
Watershed) under the 100 year,3-hour rain event. The conceptual dry detention basin
will be incorporated into the scenarios described under subtasks 10b and 10c.
l0e Run the XPSWMM model with the revisions described above under the following rain
events:
Table 1 Storm Events for Modeling
Rainfall Duration Rainfall Depth
Recurrence Interval
(hours) (inches)
10-year 3-hour 2.28*
25-year 3-hour 2.85*
100-year 3-hour 4.06*
June 2008 15-hour 4.94**
* Rainfall Frequency Atlas of the Midwest(1992)
Gallups_Merritts Amend 2
Final
1
Attachment A
Amendment#2 to Gallups/Merritts Creek Watershed Storm Water Management Plan
Brown and Caldwell Project# 148104
City of Oshkosh Reference: Authorization Date: 6/9/2015
June 11,2019
** Rain duration and depth recorded at Wittman Regional Airport,Oshkosh,WI
10f Prepare maps and tables summarizing the runoff surface ponding depth and extent for
each rain event in Table 1 under the conditions described in subtasks 10a, 10b, and l Oc.
lOg Prepare an additional section of the Gallups/Merritts Creek Watershed Regional Storm
Water Management Plan(Task 7)describing the results of the analysis under this
amendment.
10h The following meetings are included with this budget:
1) Attend(via conference call)a meeting with City Staff, Wittmann Regional Airport
representatives,and OMNNI Associates(Airport's Consultant)to discuss the
proposed Taxiway A project.
2) Hold one meeting with City Staff at the City of Oshkosh City Hall to review the
results from the initial analysis.
3) Hold a second meeting with City Staff at the City of Oshkosh City Hall to review the
results from the final analysis.
Revision to Attachment A—Schedule.
The schedule for final deliverables is revised to December 31,2019.
Budget Amendment
All work will be conducted under the terms and conditions as described in the Gallups/Merritts Creek
Watershed Storm Water Management Plan agreement dated July 1,2015. The Amendment budget is
provided below:
Additional Task Hours Costs
#10 Analysis of Culvert Crossing at South End of Airport Runway(#18—36) 88 $13,975.00
Current contract amount= $128,221.00
Amendment#1: $ 6,967.00
Amendment#2: $ 13,975.00
Amended Contract Amount: $149,163.00
Assumptions
1) All work on this amendment will be completed by December 31, 2019.
Gallups_Merritts Amend 2
Final
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