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HomeMy WebLinkAbout05(H) - Consider approval of a Resolution authorizing a Public Works Consultant Pool Work Order for the City Wide Storm Water Model Project ReportPage 1 of 2 Public Works Consultant Pool Work Order (Citywide Stormwater Model) WSB & ASSOCIATES, INCORPORATED, dba WSB This work order (“Work Order”) is issued on this _______ day of _________________, 2020 by the City of Prior Lake (“City”) pursuant to the Public Works Consultant Pool – Master Agreement dated April 20, 2020 (“Contract”) between the City and WSB & Associates, Incorporated, dba WSB (“Consultant”). Based on the mutual promises and covenants set forth herein, the sufficiency of which are hereby acknowledged, the City and Consultant agree as follows: 1. Scope of Work Order. Consultant agrees to provide, perform and complete all the services requested by the City in this Work Order and attached Exhibit 1 (“Work”), which Work shall be subject to the terms and conditions of this Work Order and the Contract. 2. Term of Work Order. All Work requested by this Work Order shall be completed by December 31, 2021. 3. Compensation for Work Order. City agrees to pay the Consultant a fixed sum of $85,000.00 as full and complete payment for the Work requested by this Work Order. 4. Consultant Representative. Consultant has designated ____________________ to manage the Work Order subject to the supervision of Consultant’s representative. ISSUED BY CITY OF PRIOR LAKE ___________________________________ City Manager RECEIVED AND ACCEPTED BY CONSULTANT _____________________________________ By:_________________________ Its:_________________________ Page 2 of 2 Exhibit 1 – Scope of Work Order G:\Group Data\WATER RESOURCES\WR Proposal Folder\Prior Lake\LTR PROP-p young-CityWide__Modeling_061620 (003).docx 701 XENIA AVENUE S | SUITE 300 | MINNEAPOLIS, MN | 55416 | 763.541.4800 | WSBENG.COM June 18, 2020 Pete Young Water Resources Engineer City of Prior Lake 4646 Dakota Street SE Prior Lake, MN 55372 Re: Proposal to provide City-Wide XPSWMM Modeling City of Prior Lake, MN Dear Mr. Young: Attached for your review and approval is our proposed scope of services, fee, and schedule for providing professional engineering services to complete a City-wide hydrologic and hydraulic XPSWMM model for the City of Prior Lake. The goal of this project is to develop a hydrologic and hydraulic model that may be used for flood mitigation projects, street improvement projects, development review, future resiliency studies, policy development, and cost-benefit analyses among other purposes. The proposed scope of services includes data collection and review, model development, model validation and calibration, and a final modeling report submitted to the City of Prior Lake. We are excited to work with you to develop the proposed City-wide model and associated report. If you are in agreement with this proposal, please sign where indicated below and return one copy. The necessary contract documents will then be provided. WSB will start work upon receipt of a signed contract. Please do not hesitate to contact me at 763-231-4861 with any questions. Sincerely, WSB Jake Newhall, PE Senior Project Manager Attachment alp ACCEPTED BY: City of Prior Lake, MN Name Title Date Mr. Pete Young June 18, 2020 Page 2 G:\Group Data\WATER RESOURCES\WR Proposal Folder\Prior Lake\LTR PROP-p young-CityWide__Modeling_061620 (003).docx SCOPE OF ENGINEERING SERVICES FOR CITY-WIDE HYDROLOGIC AND HYDRAULIC XPSWMM MODELING FOR THE CITY OF PRIOR LAKE SCOPE OF ENGINEERING SERVICES This work plan consists of the development of an XPSWMM model for the City of Prior Lake, which covers approximately 19 square miles (12,160 acres). The City is located within Prior Lake Spring Lake Watershed District and Scott County WMO. The following are the tasks that will be included as part of the model development: Task 1: Data Acquisition and Review This subtask will include the collection of background information needed for model development including drainage and hydraulic information from the City of Prior Lake. This data will include the City’s most recent storm sewer GIS mapping information and any recent H&H modeling. In addition, WSB will collect data from Scott County, the Minnesota Department of Transportation, Shakopee Mdewakanton Sioux Community, and the Minnesota Department of Natural Resources, as available. This task will also include collection and review of data from the Watersheds, including the Prior Lake Outlet Channel mode, Upper watershed model, and any other available modeling throughout the City. Following data collection and review, WSB will meet with the City of Prior Lake to present the findings and discuss data gaps and recommendations for gathering additional data or assumptions to address the gaps. This scope does not assume any survey time for addressing gaps in storm sewer or storage data. This can be added once our gaps analysis is complete if desired. This scope assumes the City will collect the record drawings for all pipes 21-inches and greater and add the rim and invert elevations into the GIS database (the database contains some diameter and invert elevations, but some gaps will need to be filled in). In addition to improving the model development efficiency, this will be a large benefit to the City to be able have this information available for future projects. We are able to assist with the record drawing gathering if desired for an additional fee. Deliverables: A technical memorandum identifying missing or unclear data, as well as recommendations to resolve data gaps. Task 2: XPSWMM Model Development A City-Wide XPSWMM model will be developed for the City of Prior Lake using industry approved modeling methodology. Model runs will include the 2-, 10-, 100-, and 500-year 24-hour rainfall events as determined using NOAA Atlas 14 and MSE3 distributions. It is important to note that the 500-year event is included to help ensure the model is built with the flexibility/capacity to be able to handle intense specific rainfall events that the City may want to run in the future as well as increased rainfall intensity and durations in the future. Drainage areas will be delineated using LIDAR and available as-built plan information. Delineations will be derived from the existing drainage area information that has been previously developed through the City’s SWAMP applications and other stormwater projects to help increase efficiency and ensure consistency. Stormwater BMPs will be included in the model; basin storage will be determined using available LIDAR data and will include only live storage of the stormwater facilities. Mr. Pete Young June 18, 2020 Page 3 G:\Group Data\WATER RESOURCES\WR Proposal Folder\Prior Lake\LTR PROP-p young-CityWide__Modeling_061620 (003).docx Tailwater conditions for the Prior Lake Outlet Channel and other major water bodies will be obtained from existing modeling. Storm sewer will be modeled to a minimum pipe size of 21-inches (unless there are select priority areas where 18-inch pipes are critical and warrant modeling). Small ponds and pervious depression areas (less than two feet deep) will be excluded from the modeling. If additional detail is desired in certain areas following the completion of the base modeling this can be completed for additional fee. Deliverables: Drainage area delineation GIS shapefile, draft XPSWMM model of the 2-, 10-, 100- and 500-year 24-hour design events. Final XPSWMM model of the 2-, 10-, 100-, and 500-year 24-hour design events. Task 3: Model Validation This task includes validating the model runoff parameters for land use within the City of Prior Lake. This will be accomplished by comparing model results to flood observations and high-water levels experienced during a minimum of 2 large rainfall events. If it is determined that model calibration is required, then monitoring data will need to be obta ined for rainfall events for comparison and use with NEXRAD Data. This scope does not assume model calibration will be necessary at this time. Task 4: Model Reporting The report will include model input and output data in tabular form, include modeling processes, and summarize results. Technical memorandums from earlier tasks will be included as separate appendices. GIS data used in model development and XPSWMM model outputs will be included in the final report. The report will include analysis and identification of locations where the system is under-sized, including areas that may be limited by catch basin inlet capacities. Maps of modeling results will be provided that include high water inundation areas and peak flooding depths for each design event. These maps will also identify any primary structures that may be impacted by floodwaters. Deliverables: A draft modeling report and appendices will be submitted to City staff for review. A meeting will be scheduled with the City to receive comments and discuss the draft report. Following the meeting, the report will be finalized incorporating comments received at the draft meeting. The final report will then be presented to City. TOTAL ESTIMATED ENGINEERING FEE The cost to provide the scope of services outlined in this proposal will be billed hourly, based on our current hourly rates. We are proposing to complete the City-Wide hydrologic and hydraulic modeling for the City of Prior Lake for $85,000. TIME SCHEDULE WSB anticipates starting the work upon authorization in July of 2020 and completion of the final modeling and reporting in Spring of 2021.