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HomeMy Public PortalAboutORD15757BILL NO. 2017-100 SPONSORED BY Councilman Henry ORDINANCE NO. 15151 AN ORDINANCE OF THE CITY OF JEFFERSON, MISSOURI, AUTHORIZING THE MAYOR AND CITY CLERK TO EXECUTE AN AGREEMENT WITH BARR ENGINEERING, IN THE AMOUNT OF $149,600.00 FOR THE DESIGN OF THE MESA, SCHELLRIDGE, AND CHICKADEE STORMWATER PROJECT. BE IT ENACTED BY THE COUNCIL OF THE CITY OF JEFFERSON, MISSOURI, AS FOLLOWS: WHEREAS, Barr Engineering has been selected as the firm best qualified to provide professional service related to the Mesa, Schellridge, and Chickadee Stormwater project; NOW, THEREFORE, BE IT ENACTED BY THE COUNCIL OF THE CITY OF JEFFERSON, MISSOURI, AS FOLLOWS: Section 1. Barr Engineering is hereby approved as the best qualified firm to provide professional services and its proposal is hereby accepted. Section 2. The Mayor and City Clerk are hereby authorized to execute an agreement with Barr Engineering for the Mesa, Schellridge, and Chickadee Stormwater project. Section 3. The agreement shall be substantially the same in form and content as that agreement attached hereto as Exhibit A. Section 4. This Ordinance shall be in full force and effect from and after the date of its passage and approval. Passed: I - Z ✓ U ( 6 0 Presiding -Officer-, ATTEST' ° 9 City CI rk Approved: I — 3 —C>0 I O Mayor Carrie Tergin APPROVED AS TO FORM: City ou elor 1553 CITY OF JEFFERSON CONTRACT FOR PROFESSIONAL SERVICES THIS CONTRACT, made and entered into the date last executed by a party as indicated below, by and between the City of Jefferson, a municipal corporation of the State of Missouri, hereinafter referred to as the "City," with offices at 320 East McCarty, Jefferson City, Missouri, 65101, and Barr Engineering Company, hereinafter referred to as the "Consultant," with offices at 1001 Diamond Ridge, Suite 110, Jefferson City, Missouri, 65109. WITNESSETH: THAT WHEREAS, the City desires to engage the Consultant to render certain technical and professional engineering services for stormwater modeling and design, hereinafter described in Exhibit A. WHEREAS, Consultant has made certain representations and statements to the City with respect to the provision of such services and the City has accepted said proposal to enter into a contract with the Consultant for the performance of services by the Consultant. NOW THEREFORE, for the considerations herein expressed, it is agreed by and between the City and the Consultant as follows: 1. Scope of Services. The City agrees to engage the services of the Consultant to render certain technical and professional engineering services for stormwater modeling and design, hereinafter described in Exhibit A. In the event of a conflict between this agreement and any attached exhibits, the provisions of this agreement shall govern and prevail. 2. Term. Consultant agrees with the City to furnish all supervision, labor, tools, equipment, materials and supplies necessary to perform, and to perform said work at Consultant's own expense in accordance with the contract documents and any applicable City ordinances and state and federal laws, by August 30, 2018. 3. Additional Services. The City may add to Consultant services or delete therefrom activities of a similar nature to those set forth in Exhibit A, provided that the total cost of such work does not exceed the total cost allowance as specified in paragraph 7 hereof. The Consultant shall undertake such changed activities only upon the direction of the City. All such directives and changes shall be in written form and approved by the Director of Public Works and shall be accepted and countersigned by the Consultant or its agreed representatives. Services that exceed the total cost allowance as specified in paragraph 7 shall be added by agreement of both parties prior to commencement of such services. 4. Existing Data. All information, data and reports as are existing, available and necessary for the carrying out of the work, shall be furnished to the Consultant without charge by the City, and the City shall cooperate with the Consultant in every reasonable way in carrying out the scope of services. The Consultant shall not be liable for the accuracy of the information furnished by the City. 5. Personnel to be Provided. The Consultant represents that Consultant has or will secure at its expense all personnel required to perform the services called for under this contract by the Consultant. Such personnel shall not be employees of or have any contractual relationship with the City except as employees of the Consultant. All of the services required hereunder will be performed by the Consultant or under the Consultant's direct supervision and all personnel engaged in the work shall be fully qualified and shall be authorized under state and local law to perform such services. None of the work or services covered by this contract shall be subcontracted except as provided in Exhibit A without the written approval of the City. 6. Notice to Proceed. The services of the Consultant shall commence as directed in the Notice to Proceed and shall be undertaken and completed in accordance with the schedule contained in Exhibit A. 7. Compensation. The total amount for professional services rendered under this shall not exceed One Hundred Forty -Nine Thousand Six Hundred Dollars ($149,600.00) for all design and consultant services. No change in compensation shall be made unless there is a substantial and significant difference between the work originally contemplated by this agreement and the work actually required. The City agrees to reimburse the Consultant on a time and materials basis in accordance with the terms of this agreement. 8. Failure to Perform, Cancellation. If, through any cause, the Consultant shall fail to fulfill in timely and proper manner its obligations under this contract, or if the Consultant shall violate any of the covenants, agreements, or stipulations of this contract, the City shall thereupon have the right to terminate this contract by giving written notice to the Consultant of such termination and specifying the effective date thereof, at least five (5) days before the effective day of such termination. The Consultant may without cause terminate this contract upon 30 days prior written notice. In either such event all finished or unfinished documents, data, studies, surveys, drawings, maps, models, photographs, and reports or other materials prepared by the Consultant under this contract shall, at the option of the City, become its property, and the compensation for any satisfactory work completed on such documents and other materials shall be determined. Notwithstanding the above, the Consultant shall not be relieved of liability to the City for damages sustained by the City by virtue of any such breach of contract by the Consultant. 2 9. Assignment. The Consultant shall not assign any interest in this contract, and shall not transfer any interest in the same (whether by assignment or novation), without prior written consent of the City thereto. Any such assignment is expressly subject to all rights and remedies of the City under this agreement, including the right to change or delete activities from the contract or to terminate the same as provided herein, and no such assignment shall require the City to give any notice to any such assignee of any actions which the City may take under this agreement, though City will attempt to so notify any such assignee. 10. Confidentiality. Any reports, data or similar information given to or prepared or assembled by the Consultant under this contract which the City requests to be kept as confidential shall not be made available to any individual or organization by the Consultant without prior written approval of the City. 11. Nondiscrimination. The Consultant agrees in the performance of the contract not to discriminate on the grounds or because of race, creed, color, national origin or ancestry, sex, religion, handicap, age or political affiliation, against any employee of consultant or applicant for employment and shall include a similar provision in all subcontracts let or awarded hereunder. 12. Independent Contractor. The Consultant is an independent contractor and nothing herein shall constitute or designate the Consultant or any of its employees as agents or employees of the City. 13. Benefits not Available. The Consultant shall not be entitled to any of the benefits established for the employees of the City and shall not be covered by the Workmen's Compensation Program of the City. 14. Liability. The parties mutually agree to the following: a. In no event shall the City be liable to the Consultant for special, indirect, or consequential damages, except those directly or approximately caused by the City arising out of or in any way connected with this contract. b. The Consultant shall indemnify and hold the City harmless from and against all claims, losses and liabilities arising out of personal injuries, including death, and damages to property to the comparative extent the same have been proximately caused by negligent acts or omissions on the part of the Consultant related to the services performed under this contract. 3 15. Insurance. Consultant shall provide, at its sole expense, and maintain during the term of this Agreement commercial general liability insurance with a reputable, qualified, and financially sound company licensed to do business in the State of Missouri, and unless otherwise approved by the City, with a rating by Best of not less than "A," that shall protect the Consultant, the City, and the City's officials, officers, and employees from claims which may arise from operations under this Agreement, whether such operations are by the Consultant, its officers, directors, employees and agents, or any subcontractors of Consultant. This liability insurance shall include, but shall not be limited to, protection against claims arising from bodily and personal injury and damage to property, resulting from all Consultant operations, products, services or use of automobiles, or construction equipment at a limit of $500,000 Each Occurrence, $3,000,000 Annual Aggregate; provided that nothing herein shall be deemed a waiver of the City's sovereign immunity. An endorsement shall be provided which states that the City is named as an additional insured and stating that the policy shall not be cancelled or materially modified so as to be out of compliance with the requirements of this Section. In the event that the policy is not renewed, Consultant will provide the City 30 days advance written notice of such event. 16. Documents. Reproducible copies of tracings and maps prepared or obtained under the terms of this Contract shall be delivered upon request to and become the property of the City upon termination or completion of work. Copies of basic survey notes and sketches, charts, computations and other data prepared or obtained under this Contract shall be made available, upon request, to the City without restrictions or limitations on their use. When such copies are requested, the City agrees to pay the Consultant its costs of copying and delivering same. 17. Nonsolicitation. The Consultant warrants that they had not employed or retained any company or person, other than a bona fide employee working solely for the Consultant, to solicit or secure this Contract, and that they have not paid or agreed to pay any company or person, other than a bona fide employee working solely for the Consultant, any fee, commission, percentage, brokerage fee, gifts, or any other consideration, contingent upon or resulting from the award or making of this . Contract. For breach or violation of this warranty, the City shall have the right to annul this Contract without liability, or, in its discretion, to deduct from the Contract price or consideration, or otherwise recover the full amount of such fee, commission, percentage, brokerage fee, gifts, or contingent fee. 18. Books and Records. The Consultant and all subcontractors shall maintain all books, documents, papers, accounting records and other evidence pertaining to costs incurred in connection with this Contract, and shall make such materials available at their respective offices at all reasonable times during the Contract and for a period of three (3) years following completion of the Contract. 4 19. Delays. That the Consultant shall not be liable for delays resulting from causes beyond the reasonable control of the Consultant; that the Consultant has made no warranties, expressed or implied, which are not expressly set forth in this Contract; and that under no circumstances will the Consultant be liable for indirect or consequential damages. 20. Illegal Immigration. Prior to commencement of the work: a. Consultant shall, by sworn affidavit and provision of documentation, affirm its enrollment and participation in a federal work authorization program with respect to the employees working in connection with the contracted services. b. Consultant shall sign an affidavit affirming that it does not knowingly employ any person who is an unauthorized alien in connection with the contracted services. C. If Consultant is a sole proprietorship, partnership, or limited partnership, Consultant shall provide proof of citizenship or lawful presence of the owner prior to issuance of the Notice to Proceed. 21. Notices. All notices required or permitted hereinunder and required to be in writing may be given by first class mail addressed to the Department of Public Works, 320 East McCarty, Jefferson City, Missouri, 65101, and Barr Engineering Company, 1001 Diamond Ridge, Jefferson City, Missouri, 65109. The date and delivery of any notice shall be the date falling on the second full day after the day of its mailing. CITY OF JEFFERSON, MISSOURI Ct4&Aa4 N - A Carrie Tergin, Mayor Date:— 3 —{ ATT -ES i r-- Ci y Clerk APPROVED AS O FO M: City ou elor RR ENGgIINEERING COMPANY Title: V' e- resident Dater 5 4 ATTEST: Title: M Exhibit A - Scope of Work Impervious -layer dataset preparation We will prepare an impervious -surface GIS dataset for the city at no cost. Barr's GIS specialists will use available color and near -infrared imagery to create a dataset to register the areas that are vegetated. This allows an accurate but preliminary quantification of -areas that are pervious (vegetated) versus those that are impervious (non -vegetated). To further refine the pervious/impervious differentiation, we will overlay mapping of buildings, road centerlines, and parcel boundaries in areas partially covered by trees. We will also overlay and examine the national wetlands inventory and public waters datasets to help filter out any false indications of impervious features created by open water. Water can have similar infrared color to pavement, so these overlaying exercises will be performed to help distinguish between the two features. As a quality check and to confirm the accuracy of the method described above, 10 uniformly distributed test areas the size of two to three city blocks that has been manually digitized by city staff, to determine the actual percentage of the test areas that are impervious. These impervious estimates will be compared with the results developed using the remote -sensing technique. Manual digitization would be expected to provide near 100 -percent accuracy in the impervious area estimates. However, manual digitization is extremely time-consuming and prohibitively expensive for most well-established cities. Experience shows that the relatively low-cost GIS -based remote -sensing methods perform at an accuracy rate of 90 to 95 percent compared to impervious datasets developed by manual digitization. This accuracy is typically significantly better than an impervious dataset that is developed using published impervious percentages based on land -use types or applying curve numbers in the modeling. Phase A -Mesa, Chickadee, and Schellridge Sites Mesa and Chickadee Sites Task 1— Review Available Information We will receive and utilize available data provided by the city, including LiDAR and other topographic data, storm sewer data (size, location, make, pipe inverts, catch basins, and catch -basin inverts of all relevant pipes and surface drainage -ways, etc.), street GIS overlay, etc. If additional pipe or topographic information needs to be obtained, we understand that the city may perform that work for cost savings considerations. Barr will gather other additional, publically available field or resource data such as soils data, Atlas 14 rain data, recorded rain events data, etc. Task 2 — Watershed and Subwatershed Delineation Major watershed and subwatershed delineations will be developed electronically through special software Barr has developed, and then field verified. This methodology has been found to be very accurate with divide work being completed at a significantly lower cost than performing the detailed delineations in the field. Subwatersheds will be delineated to single discharge points into the storm sewer, typically isolated catch basins or catch -basin clusters. Task 3 — Hydrology and Hydraulics Modeling Barr will create a detailed existing -conditions PC-SWMM model of the entire watershed impacting each site. This includes modeling the downstream system to a logical end location such as the storm sewer outfall at a stream or flowage a good distance downstream of the flooding, or where there is a significant drop (15 to 20 feet vertically) in a manhole where it can be reasonably assumed that downstream hydraulics won't impact flows from the upstream system. The model(s) will be built to the following specifications: One runoff node per group of catch basins (catch -basin cluster) draining to a single manhole connection to the storm sewer system; we assume that that hydraulic capacity of catch basins does not need to be accounted for in the model. Basin storage will be defined using depth/area curves at low points based on LiDAR elevation data and at stormwater storage facilities. All pipe segments (except catch -basin connections) will be included in the PC-SWMM model, recognizing that in some cases, the pipes may need to be manually entered based on survey, record drawings, or plans not reflected in GIS. Overland flow paths will be defined so that high water elevations do not exceed spill -crest elevations for the 100 -year event, and so that street overflows are reasonably defined. Drainage -area (subwatershed) delineations will be performed to a high level of detail using Spatial Analyst features of ArcMap or similar ArcMap tools in conjunction with LiDAR data. UDAR LAS (LAS = "LASer" file, or UDAR data exchange file) data and building outline data files will be downloaded and used in conjunction with storm -sewer pipe data to develop a hydrologically corrected elevation surface. The hydrologically corrected elevation surface will then be used to develop the "first -cut" subwatershed areas. Please note that some manual delineation efforts are often needed in urban areas where rooftops, curb and gutter, and street crowns are not captured in the LiDAR data. LAS datasets are described by Esri in more detail here: http://desktop.arcgis.com/en/arcmap/10.3/manage-data/las- dataset/what-is-a-las-dataset-.htm Subwatersheds will be divided at municipal boundaries. Development of infiltration parameters will be based on the results of impervious data development described above. Stormwater BMPs such as ponds, infiltration basins, filtration basins, and underground storage facilities will be included in the PC-SWMM model when they might have an influence on projected high water elevations for design events (if data is available for these). Boundary conditions will be defined. In areas where incoming overland flows may occur from an adjacent watershed outside of the city, modeling beyond the area of interest may be necessary to establish a reasonable estimate of inflows. If possible, we will attempt to calibrate or verify the accuracy of the existing -conditions model using information the city may be able provide, such as surveyed drift lines after a flooding event has subsided, or aerial photos or other photos taken during events that show extent of flooding at a moment in time, and rainfall information. Once the existing -conditions models have been developed and calibrated, we will use those models to confirm the conceptual design will meet design criteria. Task 4 — Conceptual Improvement Design Barr will develop a conceptual improvement design for each site. This conceptual design will be developed using modeling results and input from City staff. The deliverable for this task will be a set of draft design drawings for each site for the City's review. Task 5 — Permitting Given the complexity of site construction approvals/permitting and environmental permitting, Barr will work closely with city staff to identify all the necessary permits and approvals. We will prepare a matrix along with anticipated timeframes for obtaining the needed permits and approvals. Once the appropriate permits and approvals have been identified, we will prepare or aid the city in the preparation of permit applications and supporting submittals. If you desire, we will then meet with the permitting agency(s) to walk them through the project features. Task 6 —Final Model Revisions Barr will run any agreed-upon model refinements that result from communications regarding the conceptual improvement design. Task 7 — Design Drawings Design drawings will be finalized after final model revisions are completed and will be based modeling results and input from City staff. Design drawings will be provided to the city in electronic PDF format and will be signed and sealed by a Professional Engineer licensed in the State of Missouri. Task 8 — Quantity Estimation and Bid Tab Completion Construction quantities for the finalized designs will be estimated and provided to the City on bid tab sheets provided by the City. Table 1-1— Anticipated Costs (Mesa Site) Table 1-2 — Anticipated Costs (Chickadee Site) „01 90� b dam, Task --1: Review Available Information $1,800 y Task 2 WatershedlSubwatershed Degneatton ' $1<300 Task 3: H&H Modeling $2;500 i A- ill V overr�ent Destgnl ti $3,20b� Task 5: Permitting $11000. ' =$1,300. �i � i 1'a_sk�6!Final�lYtodeliRevtstons ,�� _ Task 7: Design Drawings .$3,500 Task8 Quarittty{EstimattonandBtd3Tab�Develo ment "� "$2,400 $2,500 Total $18,300 Table 1-2 — Anticipated Costs (Chickadee Site) „01 90� b dam, Task 1: Review Available Information $1,800 7ask2 Wat shed/Subwatershed,DeEtneatton r $ �� ' =$1,300. �i � Task 3: H&H Modeling $2,500 � Task � Concet�faliIm n � l: $3,200 rovementxDest � _ Task 5: Permitting $1,000 Task Finalitodel Revtsioris 6 6 Task 7: Design Drawings $3,500 nTask8 QuanttyEstimattonand Btd Tab Develolrnent...._._ _._ _.. _ __ 400 w ; Total $18,300 Scheliridge Site, Task 1= Review Available Information We will receive and utilize available data provided by the city, including LiDAR and other topographic data,:stoi-m sewer data (size, location, make, pipe inverts, catch' basins, and catch -basin inverts of all relevant pipes and surface drainage -ways, etc.), street GIS overlay, etc. If additional pipe ortopographic information needs to be obtained, we understand that the city may perform that work for cost savings considerations. Barr will gather other additional, publicly available field.or resource data such as soils data, Atlas 14raindata; recorded rain events data, etc. Task 2 — Watershed and Subwatershed Delineation Major watershed and subwatershed delineations. will be developed electronically through special software Barr has developed, and then field verified. This methodology has been found to be very accurate with divide work being completed at a significantly lower cost than performing the detailed delineations in the field. Subwatersheds will be delineated to single discharge points into the storm sewer, typically isolated catch basins or catch -basin clusters. Task 3 — Hydrology and Hydraulics Modeling Barr will create a detailed existing -conditions PC-SWMM model of the entire watershed impacting the site. This includes modeling the downstream system to a logical end location such as the storm sewer outfall at a stream or flowage a good distance downstream of the flooding, or where there is a significant drop (15 to 20 feet vertically) in a manhole where it can be reasonably assumed that downstream hydraulics won't impact flows from the upstream system. The model(s) will be built to the following specifications: One runoff node per group of catch basins (catch -basin cluster) draining to a single manhole connection to the storm sewer system; we assume that that hydraulic capacity of catch basins does not need to be accounted for in the model. Basin storage will be defined using depth/area curves at low points based on LiDAR elevation data and at storm water storage facilities. All pipe segments (except catch -basin connections) will be included in the PC-SWMM model, recognizing that in some cases, the pipes may need to be manually entered based on survey, record drawings, or plans not reflected in GIS. Overland flow paths will be defined so that high water elevations do not exceed spill -crest elevations for the 100 -year event, and so that street overflows are reasonably defined. Drainage -area (subwatershed) delineations will be performed to a high level of detail using Spatial Analyst features of ArcMap or similar ArcMap tools in conjunction with UDAR data. UDAR LAS (LAS = "LASer" file, or UDAR data exchange file) data and building outline data files will be downloaded and used in conjunction with storm -sewer pipe data to develop a hydrologically corrected elevation surface. The hydrologically corrected elevation surface will then be used to develop the "first -cut" subwatershed areas. Please note that some manual delineation efforts are often needed in urban areas where rooftops, curb and gutter, and street crowns are not captured in the WAR data. LAS datasets are described by Esri in more detail here: http://desktop.arcgis.com/en/arcmap/10.3/manage-data/las- dataset/what-is-a-las-dataset-.htm Subwatersheds will be divided at municipal boundaries. Development of infiltration parameters will be based on the results of impervious data development described above. Stormwater BMPs such as ponds, infiltration basins, filtration basins, and underground storage facilities will be included in the PC-SWMM model when they might have an influence on projected high water elevations for design events (if data is available for these). Boundary conditions will be defined. In areas where incoming overland flows may occur from an adjacent watershed outside of the city, modeling beyond the area of interest may be necessary to establish a reasonable estimate of inflows. If possible, we will attempt to calibrate or verify the accuracy of the existing -conditions model using information the city may be able provide, such as surveyed drift lines after a flooding event has subsided, or aerial photos or other photos taken during events that show extent of flooding at a moment in time, and rainfall information. Once the existing -conditions models have been developed and calibrated, we will use those models to evaluate up to 3 conceptual improvement designs. Task 4 —Conceptual Improvement Design Barr will develop up to 3 conceptual improvement options for the Schellridge Site. These conceptual improvement options will be developed using modeling results and input from City staff. Once City staff have selected their preferred conceptual improyv�ement option, a set of draft design drawings of this option will be provided to the City for their review. Task 5 — Draft Technical Memorandum A draft technical memorandum will be developed to document the modeling results for each conceptual improvement option described in Task 4. A summary of the benefits and considerations for each conceptual improvement option will also be included in this draft technical memorandum. The memorandum will be provided to City staff for their use in determining which conceptual improvement option to advance to a final design. Task 6 — Permitting Given the complexity of site construction approvals/permitting and environmental permitting, Barr will work closely with city staff to identify all the necessary permits and approvals. We will prepare a matrix along with anticipated timeframes for obtaining the needed permits and approvals. Once the appropriate permits and approvals have been identified, we will prepare or aid the city in the preparation of permit applications and supporting submittals. If you desire, we will then meet with the permitting agency(s) to walk them through the project features. Task 7 —Final Model Revisions and Design Basis Memorandum Development Barr will run any agreed-upon model refinements that result from communications regarding the conceptual improvement design. A Design Basis Memorandum will be developed to document the design computations, assumptions, and models used as the basis for the final design. Task 8 — Design Drawings Design drawings will be finalized after final model revisions are completed and will be based modeling results and input from City staff. Design drawings will be provided to the city in electronic PDF format and will be signed and sealed by a Professional Engineer licensed in the State of Missouri. Task 9 — Quantity Estimation and Bid Tab Completion Construction quantities for the finalized design will be estimated and provided to the City on a bid tab provided by the City. Table 1-3 — Anticipated Costs (Schellridge Site) r n 1 1 I �uwF Task_ 1: Review Available information $1,800 Task2 Watershed/Subwatershed $1,300 r SDelmeatiop`F4 Task 3: H&H Modeling $9,800 Taskr4 Conceptual'ImProvementbesign ;$6400 Tasks: Draft Technical Memorandum $3,600 Task6 Permitting - $S00 Task 7: Final Model Revisions $3,000 Task 8 Desigm-wm rags' $4 8 Task 9: Quantity Estimation and Bid Tab Development $2,800 Total $34,000 Phase 2 - Cedar Hill/Timber Lane/Satinwood give and Douglas Drive Sites Cedar Hill/Timber Lane/Satinwood. Drive Site Task 1 -Review Available Information We will receive and utilize available data provided by the city, including UDAR and other topographic data, storm sewer data (size, location,. make, pipe inverts, catch basins, and catch -basin inverts of all relevant pipes and surface'drainage-ways, etc.), street GIS overlay, etc. if additional pipe or topographic information needs to be obtained, we understand that the city may perform that work for cost savings considerations. Barr will gather other additional, publically available field or resource data such as soils data, Atlas 14 rain data, recorded rain events data, etc. Task 2 —Watershed and Subwatershed Delineation Major watershed and rsubwatershed delineations will.be developed electronically through special. software Barr has developed, and then field verified: This methodology, has been found to be very accurate with divide work being completed at a significantly lower cost than performing the detailed delineations in the field. Subwatersheds will be delineated to single discharge points into the storm sewer, typically isolated catch basins or catch -basin clusters. Task.3 — Hydrology and Hydraulics Modeling Barr will create a detailed existing -conditions PC-SWMM model of the :entire watershed. impacting the site. This includes modeling the downstream system to a logical end location such as the storm sewer outfail at a stream or flowage a. good distance downstream of the flooding, or where there is a significant drop.(15 to 20 feet vertically) in a manhole where it can be reasonably assumed that downstream hydraulics won't impact flows from the. upstream system. The model(s) will be built to the following specifications: One runoff node per group of catch basins (catch -basin cluster) draining to a single manhole connection to the storm sewer system; we assume that that hydraulic capacity of catch basins does not need to be accounted for in the model. Basin storage will be defined using depth/area curves at low points based on WAR elevation data and at stormwater storage facilities. All pipe segments (except catch -basin connections) will be included in the PC-SWMM model, recognizing that in some cases, the pipes may need to be manually entered based on survey, record drawings, or plans not reflected in GIS. Overland flow paths will be defined so that high water elevations do not exceed spill -crest elevations for the 100 -year event, and so that street overflows are reasonably defined. Drainage -area (subwatershed) delineations will be performed to a high level of detail using Spatial Analyst features of ArcMap or similar ArcMap tools in conjunction with UDAR data. LiDAR LAS (LAS = "LASer" file, or LIDAR data exchange file) data and building outline data files will be downloaded and used in conjunction with storm -sewer pipe data to develop a hydrologically corrected elevation surface. The hydrologically corrected elevation surface will then be used to develop the "first -cut" subwatershed areas. Please note that some manual delineation efforts are often needed in urban areas where rooftops, curb and gutter, and street crowns are not captured in the LiDAR data. LAS datasets are described by Esri in more detail here: http•//desktop arcgis com/en/`arcmap/10.3/manage-data/las- dataset/what-is-a-las-dataset-.htm Subwatersheds will be divided at municipal boundaries. Development of infiltration parameters will be based on the results of impervious data development described above. Stormwater BMPs such as ponds, infiltration basins, filtration basins,.and underground storage facilities will be included in the PC-SWMM model when they might have an influence on projected high water elevations for design events (if data is available for these). Boundary conditions will be defined. In areas where incoming overland flows may occur from an adjacent watershed outside of the city, modeling beyond the area of interest may be necessary to establish a reasonable estimate of inflows. If possible, we will attempt to calibrate or verify the accuracy of the existing -conditions model using information the city may be able provide, such as surveyed drift lines after a flooding event has subsided, or aerial photos or other photos taken during events that show extent of flooding at a moment in time, and rainfall information. Once the existing -conditions models have been developed and calibrated, we will use those models to evaluate several alternatives to improve the stormwater issues at this site. Task 4 — Conceptual Improvement Design Barr will develop up to 3 conceptual improvement options for the site. These conceptual improvement options will be developed using modeling results and input from City staff. These conceptual improvement options will be summarized in a draft technical memorandum described in Task 5. Task 5 — Draft Technical Memorandum A draft technical memorandum will be developed to document the modeling results for each conceptual improvement option described in Task 4. A summary of.the benefits and considerations for each conceptual improvement option will also be included in this draft technical memorandum. The memorandum will be provided to City staff for their, use in determining -What further actions to take.at the site. Task, 6—Final Model. Revisions and Design Basis Memorandum Development Barr will run any agreed-upon model refinements that result from communications regarding the. conceptual improvements. A Design Basis Memorandum will be developed to document the: design computations and assumptions incorporated into the models for each conceptual improvement option. Table 2.4 — Anticipated Costs (Cedar Hill/Timber Trail/Satinwood Drive Site) 0111", 140 asoma �r nd Task 1: Review Available information $1,800 Task2 Watershed/Sutwaterspfed Delineation ��' "� $2400 t Task 3: H&H Modeling $13,600 Task 4 Conceptual Improvement Design K' $15,300 Task 5 Draft Technical Memorandum $10,900 Taskn6 Final Motlel Revisions antl Design eas�sMemorandum, ' $4%200 Total $48,200 Douglas Drive Site Task 1— Review. Available.lnformation We will receive and utilize available data provided by -the city, including LiDAR and. other topographic data, storm sewer data (size, location, make, pipe inverts, catch basins, and catch -basin inverts of all relevant pipes and surface drainage -ways, etc.), street GIS overlay, etc.. If additional pipe or topographic information needs to be obtained, we understand that the city may perform that work for cost savings considerations. .Barr will gather other additional, publica I ly -available field or resource data such as soils data; Atlas 14 rain data, recorded rain events data, etc.. Task 2 —Watershed and Subwatershed Delineation Major watershed and subwatershed delineations will be. developed electronically'through special software Barr has developed; and"then field verified. This methodology has been found to be very accurate with divide work being completed at a significantly lower cost than performing the detailed delineations in the field. Subwatersheds will be delineated to single discharge points into the storm sewer, typically isolated catch basins, or catch -basin clusters. Task 3 —Hydrology and Hydraulics Modeling Barr will create a detailed existing -conditions PC-SWMM model of the entire watershed impacting the site. This includes modeling the downstream system to a logical end location such as the storm sewer outfall at a stream or flowage a good distance downstream of the flooding, or where there is a significant drop (15 to 20 feet vertically) in a manhole where it can be reasonably assumed that downstream hydraulics won't impact flows from the upstream system. The model(s) will be built to the following specifications: One runoff node per group of catch basins (catch -basin cluster) draining to a single manhole connection to the storm sewer system; we assume that that hydraulic capacity of catch basins does not need to be accounted for in the model. Basin.storage will be defined using depth/area curves at low points based on UDAR elevation data and at stormwater storage facilities. All pipe segments (except catch -basin connections) will be included in the PC-SWMM model, recognizing that in some cases, the pipes may need to be manually entered based on survey, record drawings, or plans not reflected in GIS. Overland flow paths will be defined so that high water elevations do not exceed spill -crest elevations for the 100 -year event, and so that street overflows are reasonably defined. 1 Drainage -area (subwatershed) delineations will be performed to a high level of detail using Spatial Analyst features of ArcMap or similar ArcMap tools in conjunction with UDAR data. HDAR LAS (LAS = "LASer" file, or WAR data exchange file) data and building outline data files will be downloaded and used in conjunction with storm -sewer pipe data to develop a hydrologically corrected elevation surface. The hydrologically corrected elevation surface will then be used to develop the "first -cut" subwatershed areas. Please note that some manual delineation efforts are often needed in urban areas where rooftops, curb and gutter, and street crowns are not captured in the WAR data. LAS datasets are described by Esri in more detail here: http•//desktop arcgis.com/en/arcmap/10.3/manage-data/las- dataset/what-is-a-las-dataset-. htm Subwatersheds will be divided at municipal boundaries. Development of infiltration parameters will be based on the results of impervious data development described above. Stormwater BMPs such as ponds, infiltration basins, filtration basins, and underground storage facilities will be included in the PC-SWMM model when they might have an influence on projected high water elevations for design events (if data is available for these). Boundary conditions will be defined. In areas where incoming overland flows may occur from an adjacent watershed outside of the city, modeling beyond the area of interest may be necessary to establish a reasonable estimate of inflows. If possible, we will attempt to calibrate or verify the accuracy of the existing -conditions model using information the city may be able provide, such as surveyed drift lines after a flooding event has subsided, or aerial photos or other photos taken during events that show extent of flooding at a moment in time, and rainfall information. Once. the existing -conditions models have been developed and calibrated, we will use those models to evaluate several alternatives -to improve the stormwater issues at this site. Task 4 — Conceptual Improvement Design Barr will develop up to 3 conceptual improvement options for the site. These conceptual improvement options will be developed using modeling results and input from City staff. These conceptual improvement options will be summarized in a draft technical -memorandum described in Task 5. Task 5 — Draft Technical Memorandum A drafftechnical memorandum will be developed to document the modeling results for each conceptual improvement option described in Task 4. A summary of the benefits and considerations for each conceptual improvement option.will also be included in this draft technical memorandum. The memorandum will be provided to City staff for their use in determining what further actions to take at the site. Task 6 —Final Model Revisions and Design Basis Memorandum Development Barr will run any agreed-upon model refinements that result from communications regarding the conceptual improvements. A Design Basis Memorandum will be developed to document the design computations and assumptions incorporated into the models for each conceptualimprovement option. Table 2 - 5 — Anticipated Costs (Douglas Drive Site) g Task 1: Review. Available Information $1,800 Task 2 Watershed/Su watershed fheation ' ` $2,400 !M . _ _ Task 3: H&H Modeling $8,500 Task 4 Co ceptual Improyemet�t Desi n� : x$8,700 Task 5: Draft Technical Memorandum $5,700 Basis,Memorandtrin�� $3,700, ,Task 6 �F�hal,iVlotlel Revisions and=Design u x _ .__ ? Total $30,800