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Home My WebLink AboutContract 45519-A1 CITY SECRIETAW� / CONTRACT N0. �- AMENDMENT No.1 TO CITY SECRETARY CONTRACT No. 45519 WHEREAS, the City of Fort Worth (CITY) and Halff Associates, Inc. , (ENGINEER) made and entered into City Secretary Contract No. 45519, (the CONTRACT) which was authorized by M&C C-26501 on the 15th day of October, 2013 in the amount of $ 438, 000; and WHEREAS, the CONTRACT involves engineering services for the following project: McCart/Berry Flood Mitigation Study; and WHEREAS, it has become necessary to execute Amendment No. 1 to the CONTRACT to include an increased scope of work and revised fee. NOW THEREFORE, CITY and ENGINEER, acting herein by and through their duly authorized representatives, enter into the following agreement, which amends the CONTRACT: 1. Article I of the CONTRACT is amended to include the additional engineering services specified in a proposal dated July 26, 2016, a copy of which is attached hereto and incorporated herein. The cost to City for the additional services to be performed by Engineer totals $44 ,272. (See Attached Funding Breakdown Sheet, Page -3-) 2 . Article II of the CONTRACT is amended to provide for an increase in the fee to be paid to Engineer for all work and services performed under the Contract, as amended, so that the total fee paid by the City for all work and services shall be an amount of $482,272. 3. Article III, of the CONTRACT is hereby amended to extend the termination date by an additional 18 months to allow for completion of the subject matter. City Fort Worth OFFICIAL RECORD Professional Services Agreement Amendment Template PMO Official Release 8/1/2012 Page 1 of 3 CITY SECRETARY FT. WORTH, TX 4 . All other provisions of the Contract, which are not expressly amended herein, shall remain in full force and effect. EXECUTED and EFFECTIVE as of the date last written by a signatory, below. APPROVED: City of Fort Worth ENGINEER Halff Associates, Inc. Jesus J. C12apa BE61jamin B. ylant Assistant City Manager Project Manager DATE: ��i' DATE: 46 APPROVAL RECOMMENDED:Ck4� aL & - '� Douglas . Wiersig, P.E Director, Transportation and Public Works Department APPROVED AS TO FORM AND LEGALITY: M&C: n/a (�7k � Date: n/a Douglas W. Black Assistant City Attorney ATTEST: ®� F®/g 0 Mary J. r , City Secretary AS OFFICIAL RECORD City of Fort Worth CITY SECRETARY Professional Services Agreement Amendment Template FT.WORTH,TX PMO Official Release 8/1/2012 Page 2 of 3 FUNDING BREAKDOWN SHEET City Secretary No. 45519 Amendment No. 1 Department Fund-Account-Center Amount 020E431 52002-5330500-100091 $44, 272 . 00 Total: $44, 272 . 00 City of Fort Worth Professional Services Agreement Amendment Template PMO Official Release 8/1/2012 Page 3 of 3 mom HALFF July 26, 2016 AVO 30149a Ms.Jennifer Dyke, CFM City of Fort Worth Storm Water Division Transportation and Public Works 1000 Throckmorton Fort Worth,TX 76102 RE: Contract Amendment for McCart/Berry Flood Mitigation Study — Amendment to City Secretary Contract No.45519 Dear Ms. Dyke: Halff Associates is pleased to present this Amendment to the Scope of Services for the above referenced project. At the request of the City, the contract is being initiated on a task order basis. Each new task is initiated with a written request from the City. A task is closed after all deliverables are provided. This amendment includes additional tasks for the analysis of the impacts of development on the future flood risk in the watershed (Task 4) and evaluation of the Sandage Avenue storm drain relief line (Task 7A). Included is the standard Amendment to Professional Services, Scope of Work (Attachment "Al"), and Level of Effort(Attachment B) to be considered under this amendment. Thank you for the opportunity to allow Halff to continue assisting the City with this important project, if you have any questions please feel free to contact me at(817) 764-7488. Sincerely, HALFF ASSOCIATES, INC. Benjamin B. Pylant, PE, CFM Project Manager C: HALFF ASSOCIATES,INC. 4000 FOSSIL CREEK BOULEVARD TEL (817)847-1422 WWW HALFF.COM FORT WORTH,TX 76137-2720 FAX (817)232-9784 ATTACHMENT "A1" Scope of Work McCart/Berry Flood Mitigation Study City Secretary Contract No. 45519 The scope set forth herein defines the work to be performed by the ENGINEER in completing the study. Both the CITY and ENGINEER have attempted to clearly define the work to be performed and address the needs of the study. Under this scope, "ENGINEER" is expanded to include any sub-consultant, including surveyor, employed or contracted by the ENGINEER. OBJECTIVE ENGINEER will include the tasks required to complete additional evaluation of the Sandage Avenue storm drain relief line and analysis of the impacts of development on the future flooding risk in the watershed. WORK TO BE PERFORMED The CITY has requested that the current Flood Mitigation Study be expanded to include additional analysis. The ENGINEER will provide the following services and provide the requested deliverables: Task 1: Project Management The ENGINEER shall attend regular study meetings with the City. These meetings will include a review of the study, and will discuss the pertinent activities associated with the study. ENGINEER will prepare an agenda and meeting minutes. This amendment includes project management effort associated with the additional tasks and scope of work will be consistent with the original contract. Task 4: Impacts of Development The purpose of this Task is to identify areas of potential impact as depicted in model simulation results (depth, spatially, or elevation) for 2 scenarios of future development. This is to be accomplished through the use of hydrology scenarios and hydraulics results comparisons. The definition of"impact" relates to the criteria of 0.1-foot increase or more in calculated water surface elevations at a point of interest as described in Fort Worth criteria or iSWM manual. The hydrologic calculations of each scenario and subsequent hydraulic simulation outcome for development impacts shall be evaluated based on review of inundation mapping. Consultant will utilize the computer models developed under Task 3 and the existing condition Scenario 1 results for the Task 4 comparisons. The future condition scenarios described in the following sections will be developed as the basis for the comparisons. In assessing these future conditions all existing Park property is to remain Park. A meeting will be held with city staff prior to proceeding with this Task to confirm future land use conditions to be used. The Consultant shall prepare comparison tables, map exhibits, flood extents delineation and prepare a summary Technical Memorandum to document the analysis. City of Fort Worth,Texas Attachment A PMO Release Date:07123/2012 Pagel of 34 Scenario 1 - Existing Conditions Utilizing the latest InfoWorks ICM models for the study area, utilizing the city's imperviousness layer in GIS, to determine the following: Existing Conditions hydrology is to be based on the GIS generated impervious cover polygon layer contained within the City's GIS. Impervious cover is identified in GIS as the following surfaces that exist on the ground today: • SFR homes • NSFR apartments, businesses and industrial sites • Streets, sidewalks, patios, driveways, rooftops, etc. The consultant is to clip this layer to each individual model subbasin using GIS. The consultant should utilize File Geodatabases to house each of these datasets, as it will track the Shape Area (in square feet, if the data is in State Plane) automatically. Then the impervious cover polygon area within each individual subbasin divided by each subbasin's area equals the % impervious for each subbasin. Consultant will review the impervious cover polygon layer in comparison with available aerial photos provided by the City, and agree that it fairly represents the impervious cover on the ground today, or adjust it for any major existing development change that may significantly impact the impervious cover not reflected in the GIS layer. Any adjustments are to be reported to the city. To identify areas of potential impact as depicted in model simulation results (depth, spatially, or elevation) two (2) scenarios of future development are to be considered. This is to be accomplished through the use of hydrology scenarios and hydraulics results comparisons. The definition of"impact" relates to the criteria of 0.1-foot increase or more in calculated water surface elevations at a point of interest as described in Fort Worth criteria or iSWM manual. The hydrologic calculations of each scenario and subsequent hydraulic simulation outcome for development impacts shall be evaluated based on review of inundation mapping. Consultant will utilize the ICM models and the existing condition Scenario 1 results for the comparisons. The future condition scenarios described in the following sections will be developed as the basis for the comparisons. A meeting will be held with city staff prior to proceeding with this Task. The Consultant shall prepare comparison tables, map exhibits, flood extents delineation and prepare a summary Technical Memorandum to document the analysis. A. Scenario 2-Existing NSFR, Fully Developed SFR: The hydrology model for this scenario will be developed to represent the full build out condition of current zoned residential properties. The Scenario 2 model hydrology is based on the existing conditions GIS impervious cover layer in all areas that are NOT SFR, and based on the Zoning layer impervious cover values within areas that are SFR. This represents holding NSFR impervious constant (same as existing condition Scenario 1) while increasing the SFR from existing conditions up to the full build out condition impervious conditions. The SFR "average" percent impervious cover values in Fort City of Fort Worth,Texas Attachment A Page 2 of 6 Worth criteria or iSWM manual are to be used. To produce this model, the consultant will: 1. Export all "A" zoned residential areas into its own feature class called "SFR". Select by attributes "Zoning = A-5 OR Zoning = A-10 OR Zoning =...". This represents all the SFR within the basin. 2. Invert the selection. This should then select everything in the zoning layer that is NOT SFR. Export this to its own feature class. Call it NSFR. 3. Clip the Impervious Cover data to the NSFR layer. Make sure nothing is selected. This will then clip down the impervious cover layer to only shapes within the NSFR polygons. Call this layer NSFR_IMP_clip 4. Divide the total area of NSFR_IMP_Clip by the total area of NSFR to get the EXISTING percent impervious cover within the NSFR only area. 5. Dissolve the SFR feature class by the "Zoning" field. This will produce a feature class with 1 feature per zoning classification. Call it SFR_Diss 6. Assign the corresponding "Average % Impervious" values to all the Zone A areas in SFR_Diss. 7. Calculate the area weighted average of nSFR % impervious and all the Zone A SFR Diss %. n F I� i Suabaaln%Im rvipus ride Area ID Area(SF] 'A Impwv A r%I h{S i 444300y-1.1 74.7 3.32073740 A-10 I�i2147.-75 49 _ 794179.51 A-5 268912.43 61 16403658 Total 4728129.39 73.9 349271578 B. Scenario 3 - Fully Developed SFR and Fully Developed NSFR: The hydrology model for this scenario is based on the assumption that all land (both SFR and NSFR) will be fully built out to contain facilities consistent with its current zoning classification. This effort will consider a scenario that assumes new zoning from the City of Fort Worth,Texas Attachment A Page 3 of 6 Berry/University Plan and compares impacts to existing zoning for future impacts. It assumes that currently vacant land or semi-developed land will ultimately be constructed on or finished constructing and will leave no vacant/open/undeveloped land areas. Review land use to ensure that existing park land remains in park land category under full build-out scenario. This model will use only the zoning layer and the associated Avg. Percent Impervious values from Fort Worth criteria or iSWM Manual. This hydrology for this scenario will be accomplished by: 1. Clip ADM—Zoning layer to subbasin. 2. Dissolve the clip by zoning classification. 3. Apply Avg. % impervious cover values from Table 1 to each distinct classification. 4. Calculate the total subbasin % impervious cover. a. r r 1 h rr�6 Avg,% • s 1 Polygon A-10 651.778 16207.75 49 7941.79505 2 Polygon A-5 6259.561 268912.4 61 164036.5849 3 Polygon B 11078.55 982037 65 638324.0466 4 Polygon IC 13074.331 1331355 551 732245.1473 5 Polygon CF 2849.303 225294.5 85 191500.3486 6 Polygon D 2063.732 123333.4 65 80166.73784 7 Polygon E 4670.12 234999.3 96 225599.3469 8 Polygon F 568.5796 19534.09 96 18752.73102 9 Polygon NS-T4 4283.112 312850.3 96 300336.2966 Not in Table 1 10 Polygon NS-T51 4338.558 1088436 961 1044898.795 Not in Table 2 11 Polygon PD 3135.2371 125169.5 85 106394.0448 Total 1 4728129 74.21 3510195.874 Hydraulic Analysis: Execute the model under both future development conditions and document the potential impacts from development including increases in inundation depth potentially impacting structures. Analysis for each scenario shall include a comparison of water surface elevations at points of interest between existing conditions and future conditions City of Fort Worth,Texas Attachment A Page 4 of 6 1. In areas with only a 1D model of the storm system, the following shall be considered: a. Profile plots comparing existing and proposed/Future conditions system HGL for a range of storm events and durations b. Compare HGL's at inlets or other points of interest c. Estimate inundation extents by projecting HGL on study terrain/surface d. Note flood risk to any structures/roadways by comparing existing system and proposed/Future depths adjacent to flooded or threatened structures. 2. In areas modelled with a 1 D/2D model that includes both confined (1D) and unconfined (2D) flows or only unconfined (2D) flows, the following shall be considered: a. Profile plots comparing existing and proposed/Future conditions system HGL for a range of storm events and durations. b. Utilize terrain data and surface model to execute 2D surface flood mapping for existing and proposed/Future conditions. c. Compare HGL and 2D flood elevations at points of interest; d. Compare 2D inundation mapping for existing Scenario 1 and future build out conditions (Scenarios 2 and 3); e. Estimate inundation extents from 1 D/2D model on terrain/surface; f. Use inundation maps to illustrate flood risk to any structures/roadways by comparing existing system and proposed/future development condition depths adjacent to flooded or threatened structures. (Note-This is not a detailed Flood Hazard Assessment as described in the Task 3 scope for Scenario 1. Rather it is development and review of inundation mapping for the 2 future development scenarios in comparison with existing conditions for the City's use to characterize the potential impact of future development). C. Technical Memorandum: Document and summarize the Task 4 analysis in a technical memorandum. Memorandum should present study findings and summarize discussions with City on how it may be applied during the SWM Development Review process, including evaluation of the differential in impervious cover for each watershed, identification of the areas available to be developed from open space condition, and definition of zones in which the SWM review process could be greatly simplified. Deliverables • Technical Memorandum summarizing Task 4 analysis for City's use. • 2 Meetings — 1 at kick off of task and 1 to discuss findings with City Task 7: Regional Drainage Improvements Alternative Development The Halff Team will refine alternatives with hydraulic modeling. A. Hydraulic Analysis: The Consultant will develop hydraulic models of the concept alternatives to evaluate the hydraulic benefit. The modeling will focus on the 5-year (or feasible event) alternatives. The 100-year storm event will also be modeled. City of Fort Worth,Texas Attachment A Page 5 of 6 1. Model TCU East Campus Master Plan and Zoo Creek Improvements: Develop an alternative using ICM to evaluate the impacts of a proposed 10'x10' box culverts from Berry Street to the outfall at Zoo Creek along Sandage Avenue. Include an analysis for a detention pond option at the outfall to Zoo Creek. Provide a technical memorandum summarizing modeling results. 2. Benefits will be documented in terms of flood reduction depths and inundation removed from structures. Detailed benefit cost analyses is not included in this scope of work and will be considered an additional service. A table summarizing inundation depths at selected road crossing for the study area will be provided. 3. Consultant will prepare GIS exhibits to depict alternatives and show inundation mapping. Deliverables: • ICM runs of individual alternatives • Technical memo describing TCU East Campus Master Plan alternatives and Sandage Avenue storm drain relief line. • Table of benefits • GIS Exhibits City of Fort Worth,Texas Attachment A Page 6 of 6