HomeMy WebLinkAboutEarth Tech # 84350 AmendmentEarthTech
A t1JC0 International Ltd. Company
December 24, 2007
Mr. David Patek
Department of Public Works
215 Church Avenue
P.O. Box 1130
Oshkosh WI 54903 -1130
1210 Fourier Drive P 608.836.9800
Suite 100 F 608.836.9767
Madison, WI 53717 www.earthtech.com
Subject: Amendment #2 Request to Stormwater Management Planning Contract
UW- Oshkosh Campus Pollution Modeling
Earth Tech Project No. 84350
Dear Mr. Patek:
This letter is requesting an amendment to the scope and budget for the above referenced
project. The scope items detailed below have been reviewed by city staff. The scope change
described below is to conduct the stormwater pollution modeling analysis on the UW- Oshkosh
campus area. It is my understanding that these costs will be reimbursed to the city from the
UW- Oshkosh under the city's current agreement with the campus.
Description of Additional Project Tasks: UW- Oshkosh Campus Stormwater Pollution
Modeling
A. SCOPE OF WORK
1. Background
The University of Wisconsin - Oshkosh (University) (NR 216) Permit will require an
estimate of the annual nonpoint source pollution loadings for all storm sewer outfalls that
meet the regulatory definition of an "MS4" (municipal separate storm sewer system). This
pollution loading analysis is used to establish the pollution reduction goals required for
the campus grounds.
Earth Tech will use WinSLAMM to model annual pollutant loadings under the following
scenarios: (1) base conditions (October 1, 2004, land use conditions with no Best
Management Practices [BMPs] applied), (2) existing conditions with the existing levels of
BMPs; and (3) existing conditions with additional proposed BMPs to achieve an overall
total suspended solids (TSS) reduction of 20 percent and 40 percent from the base
condition. Cities under the NR 216 permit system are analyzed under the same
scenarios. The pollutant to be modeled is total suspended solids (TSS) and total
phosphorus (TP). Below are the tasks that will be conducted to achieve these goals.
a) Task 1: Create the WinSLAMM Input Database
To the extent possible, Earth Tech will use information developed during the
EarthTech
A tgCO International Ltd. Company
Mr. David Patek
Stormwater Plan Change Order Request #2
December 24, 2007
Page 2
previous stormwater management planning process for the University. Additional
and updated information will be provided by the University that reflects current
land and drainage conditions. This information includes land use, drainage basins
for each outfall (provided by the University), and existing BMPs, both structural
and nonstructural. Earth Tech will meet with the University to review the data and
clarify modeling issues and requirements. The University will provide a final
review of the updated land use conditions. Earth Tech will prepare the
geo- information to use in the WinSLAMM model. This will include characterizing
the University drainage subbasins by soil type, drainage type, and land use (as
defined under the WinSLAMM system).
b) Task 2: Run WinSLAMM - Base and Existing BMP Conditions
Earth Tech will estimate annual loadings of nonpoint source pollutants for TSS
and TP using the WinSLAMM model. Earth Tech will perform two model runs:
1) Base conditions without BMPs. Base conditions are defined by NR 216
and subsequent policy memos put out by the Wisconsin Department of
Natural Resources (WDNR). Earth Tech will conduct this analysis in
accordance with the Administrative Code and WDNR guidelines. In
general, the "base conditions" represent the urban stormwater pollution
that existed under the land use conditions as of October 1, 2004, with no
management practices. The TSS loading under base conditions
establishes the "benchmark" against which the 20 percent and 40 percent
TSS reductions are measured against.
2) Existing conditions with current BMPs. This analysis will show the level of
TSS control the University is currently achieving accounting for the current
level of management.
C) Task 3: Conceptual Evaluation of Additional BMP Types and Locations
Earth Tech will meet with the University to review and evaluate potential
additional BMP types and locations. The evaluation process will be an "in office"
process and will incorporate criteria such as: (1) available open space, (2) retrofit
of existing stormwater management practices, (3) scheduled street or parking lot
reconstruction areas for "in -line" systems, and (4) redevelopment sites with
potential for incorporation of BMPs. Upon selection of potential BMP types and
locations, Earth Tech will re -run WinSLAMM to estimate the level of TSS control
achieved. BMPs will be added until the 20 percent and 40 percent goals are
reached. This task may be conducted in a joint meeting with representatives from
the City of Oshkosh to include potential off - campus BMPs.
d) Task 4: Prepare Letter Report
Earth Tech will prepare a letter report which: (1) documents modeling
EarthTech Mr. David Patek
A tyco international Ltd. company Stormwater Plan Change Order Request #2
December 24, 2007
Page 3
methodology, (2) compiles annual loadings by sewer system outfall into an
appropriate tabular format, and (3) summarizes the potential BMPs. The report
will also contain GIS maps displaying the results of the modeling; and the
potential locations of proposed BMPs. The University will review this report before
it is finalized. Earth Tech will provide 10 hard copies of the final report to the
University. The final deliverable will also include electronic files (Excel, MSWord,
WinSLAMM, and ArcGIS) developed during the process of conducting this Scope
of Work.
B. ASSUMPTIONS
1. The University shall furnish Earth Tech all available maps, orthophotographs,
stormwater conveyance system drawings, stormwater management plans,
stormwater drainage basin delineations, parcel graphical and tabular data, and
other relevant stormwater management data, all of which Earth Tech may rely
upon without independent verification in performing the Scope of Work. It is also
assumed that the above information will be provided at no cost to the project.
Data files will be provided digitally to Earth Tech on a CD if available or paper
copy format (if a digital format is not available).
2. Some information provided by the University may be inaccurate or unreliable.
Earth Tech cannot be responsible for inaccuracies in the data supplied by the
University. Field verification of the data is not included in the Scope of Work.
3. Field surveying is not included in the Scope of Work. Also, field work to inspect
potential new BMP sites (for Task 3) is not included in the Scope of Work.
4. The Scope of Work includes up to three (3) project meetings to be held at the
University.
C. SCHEDULE
The Scope of Work can be completed within five (5) months of the notice to proceed.
D. BUDGET
TASK
Task Cost
Labor Hours
Task 1: Create WinSLAMM Input Database
$ 3,413
38
Task 2: Run WinSLAMM- Base & Existing
$ 1,995
22
Task 3: Evaluate BMP Types/Locations
$ 3,707
40
Task 4: Prepare Letter Report
$ 3,066
34
Total:
$ 12,200
134
�`J, EarthTech Mr. David Patek
A tyco international eta. company Stormwater Plan Change Order Request #2
December 24, 2007
Page 4
If everything is in order, please have both copies signed and return one fully signed copy to me.
Thank you for you consideration of this request and please do not hesitate to contact me with
any questions.
Sincerely,
6 ames A. Bachhuber
Water Resources Department Manager
cc: James Rabe; City of Oshkosh
Edward A. Nokes, City Comptroller
I hereby certify that the necessary provisions
Have been made to pay the liability which will
Accrue under this contract.
Signed for and in behalf of the City of Oshkosh