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174343.00 - As-Built Survey Review Memo - Connecticut River Levee_5-22-20 May 22, 2020 File No. 01.0174343.00 Mr. David Veleta. P.E. – City Engineer City of Northampton Department of Public Works 125 Locust Street Northampton, Massachusetts 01060 Re: Review of Existing As-built Drawings - Connecticut River Levee System FEMA Certification/Accreditation Efforts Northampton, Massachusetts Dear Mr. Veleta, In accordance with our contract (WF7-19-2019), GZA is pleased to provide the City of Northamp- ton Department of Public Works (DPW) this letter summarizing our review of existing as-built information and our recommendations for supplemental survey information for the Connecticut River Levee System. The purpose of this letter is to provide an evaluation of the suitability and completeness of the existing as-built survey completed in 2015 relative to requirements of the FEMA guidelines. This letter is subject to the Limitations provided in Attachment A. Detailed “as-built” information is required to support the City’s efforts to obtain levee certifica- tion/accreditation for the Northampton Flood Protection System from the Federal Emergency Management Agency (FEMA) in accordance with 44 CFR 65.10. For successful accreditation, FEMA guidelines require that “Data submitted to support that a given levee system complies with the structural requirements … must be certified by a registered professional engineer. Also, certified as-built plans of the levee must be submitted.” REVIEW OF EXISTING AS-BUILT SURVEY INFORMATION GZA’s evaluation of the existing as-built data for the Connecticut River Levee System included review of information from the following sources: • A drawing set entitled “Plan of Land in Northampton, MA,” sheets 1 through 8, dated April 16, 2015, prepared by Northeast Survey Consultants, showing an existing conditions topographic survey of the Connecticut River Levee System; • Discussions with the City as well as email correspondence with the City dated 12/11/19, 1/7/20, and 1/28/20; and • GZA’s general observations made during our subsurface investigation program com- pleted between 12/12/19 and 1/22/20. In general, the marked-up 2015 as-built drawings prepared by Northeast Survey Consultants, provided as Attachment B to this letter, appear to be useable to satisfy FEMA’s “as-built” re- quirements, with some limited additions and refinements. GZA and the City have identified miss- ing information from the 2015 survey on the Connecticut River Levee System, and it is also our understanding that there have been several specific enhancements/changes that have occurred since the 2015 survey. The missing information, specific site changes, and required updated sur- vey locations include: May 22, 2020 File No. 01.0174343.00 FEMA Certification/Accreditation Efforts for the Connecticut River Levee System Page | 2 Proactive by Design • Original baseline/centerline and stationing are missing; • Spot grades are typically needed about every 300 feet along the levee alignment and on top of the floodwall, but are missing; • Surface type (i.e. asphalt, gravel, etc.) are missing from road labels crossing the levee alignment; • Tree clearing was completed on and adjacent to the levee since the last survey, changing the tree line from what is shown on the current drawings; • Invert elevations are missing from the manholes and catch basins associated with the drainage pipe running along Eastern Avenue until it reaches the toe of the levee, then running southeasterly along the toe of the levee in the 24-inch HDPE drainage pipe, terminating at the catch basin located in the property at 30 Williams Street, south of the levee toe; • Rim elevation of the existing catch basin upstream of the Eastern Avenue are missing; • Rim elevation of the existing sewer manhole upstream of Eastern Avenue are missing; • Elevations (rim and invert) of toe drain manholes and toe drain pipe sizes are missing; • Inverts of some critical structures (i.e. drainage structures) shown on original USACE plans are missing; • Location of the abandoned water line under the levee, west of Route 5 is missing; • Elevations (rim and invert) and pipe sizes of three sewer manholes southwest of the Route 5 closure structure are missing; • Top of concrete headwall elevations at the two closure structures are missing. • The Hockanum Road and Ventures Field gates at levee crest were replaced; • The earthen portion of the levee was raised/regraded adjacent to the concrete floodwall on both sides of the Hockanum Pump Station (levee height increase and regrading was completed along the crest, embankment, and an area extending laterally 50-feet both the landside and riverside from the toes of the levee); • New monitoring pins were installed on the floodwall at the Pump Station; • A new Pomeroy Terrace Trail sign was installed; • A new water main was installed on Pleasant Street in the vicinity of the closure structure; • New covers for the Pleasant Street closure structure uprights were installed; • Various new underground utility installations have occurred. GZA understands that the City has the exact loca- tions for such changes and can provide a surveyor with the required information to be able to update the as-built information as required; • A new sidewalk was installed across the levee along Route 5 as part of roundabout construction (pavement edge and sidewalk elevation modified); and • The guardrail locations on the land side of the levee at Route 5 changed as part of the roundabout construction. RECOMENDATIONS Based on our review of the available as-built survey drawings (2015), as well as the input provided by the City, GZA rec- ommends performing supplemental survey to acquire additional information along the Connecticut River Levee System. We recommend that information pertaining to the missing and enhanced/changed items listed above be collected, ob- tained, and/or gathered as necessary. In addition, any new features not listed above (i.e. utilities, signs, utility poles, May 22, 2020 File No. 01.0174343.00 FEMA Certification/Accreditation Efforts for the Connecticut River Levee System Page | 3 Proactive by Design traffic signs, hydrants, etc.) within 15 feet of the levee toe should be surveyed. Refer to Attachment B for the 2015 Connecticut River Levee Survey Drawings with detailed mark-ups of the required survey. The survey information collected should subsequently be used to update the as-built drawings, which should be stamped by a licensed land surveyor. It is also possible that additional survey requirements may be identified during our remaining Year 1 scope of work. The completion of the supplemental survey is not currently included in our Year 1 scope of work or budget. However, based on our proposal for the Year 1 scope of work, we anticipate including an allowance for the supplemental survey in our Year 2 scope of work. As we continue to progress through the Year 1 scope of work and the required scope of work for Year 2 becomes clear, GZA will develop and submit a contract amendment to the City which will include the survey allowance. Please feel free to contact us if you have any questions or comments regarding the content of this memorandum. Attachments: Attachment A – Limitations Attachment B – Marked-Up 2015 Connecticut River Levee Survey Drawings (Sheets 1 through 8) Very truly yours, GZA GEOENVIRONMENTAL, INC. Christopher L. Baker, P.E. Tom Jenkins, P.E. Project Manager Consultant/Reviewer Matthew A. Taylor, P.E. Principal J:\170,000-179,999\174343\174343-00.CLB\Memos\As-Built Letters\174343.00 - As-Built Survey Review Memo - Conneticut River Levee_5- 22-20.docx ATTACHMENT A LIMITATIONS DAM ENGINEERING REPORT LIMITATIONS 01.0174343.00 Page | 1 April 2012 Proactive by Design USE OF REPORT 1. GZA GeoEnvironmental, Inc. (GZA) prepared this report on behalf of, and for the exclusive use of The City of Northamton (Client) for the stated purpose(s) and location(s) identified in the Report. Use of this report, in whole or in part, at other locations, or for other purposes, may lead to inappropriate conclusions; and we do not accept any responsibility for the consequences of such use(s). Further, reliance by any party not identified in the agreement, for any use, without our prior written permission, shall be at that party’s sole risk, and without any liability to GZA. STANDARD OF CARE 2. Our findings and conclusions are based on the work conducted as part of the Scope of Services set forth in the Report and/or proposal, and reflect our professional judgment. These findings and conclusions must be considered not as scientific or engineering certainties, but rather as our professional opinions concerning the limited data gathered during the course of our work. Conditions other than described in this report may be found at the subject location(s). 3. Our services were performed using the degree of skill and care ordinarily exercised by qualified professionals performing the same type of services at the same time, under similar conditions, at the same or a similar property. No warranty, expressed or implied, is made. SUBSURFACE CONDITIONS 4. If presented, the generalized soil profile(s) and description, along with the conclusions and recommendations provided in our Report, are based in part on widely-spaced subsurface explorations by GZA and/or others, with a limited number of soil and/or rock samples and groundwater /piezometers data and are intended only to convey trends in subsurface conditions. The boundaries between strata are approximate and idealized, and were based on our assessment of subsurface conditions. The composition of strata, and the transitions between strata, may be more variable and more complex than indicated. For more specific information on soil conditions at a specific location refer to the exploration logs. The nature and extent of variations between these explorations may not become evident until further exploration or construction. If variations or other latent conditions then appear evident, it will be necessary to reevaluate the conclusions and recommendations of this report. 5. Water level readings have been made in test holes (as described in the Report), monitoring wells and piezometers, at the specified times and under the stated conditions. These data have been reviewed and interpretations have been made in this Report. Fluctuations in the groundwater and piezometer levels, however, occur due to temporal or spatial variations in areal recharge rates, soil heterogeneities, reservoir and tailwater levels, the presence of subsurface utilities, and/or natural or artificially induced perturbations. GENERAL 6. The observations described in this report were made under the conditions stated therein. The conclusions presented were based solely upon the services described therein, and not on scientific tasks or procedures beyond the scope of described services or the time and budgetary constraints imposed by the Client. 7. In preparing this report, GZA relied on certain information provided by the Client, state and local officials, and other parties referenced therein available to GZA at the time of the evaluation. GZA did not attempt to independently verify the accuracy or completeness of all information reviewed or received during the course of this evaluation. 8. Any GZA hydrologic analysis presented herein is for the rainfall volumes and distributions stated herein. For storm conditions other than those analyzed, the response of the site’s spillway, impoundment, and drainage network has not been evaluated. DAM ENGINEERING REPORT LIMITATIONS 01.0174343.00 Page | 2 April 2012 Proactive by Design 9. Observations were made of the site and of structures on the site as indicated within the report. Where access to portions of the structure or site, or to structures on the site was unavailable or limited, GZA renders no opinion as to the condition of that portion of the site or structure. In particular, it is noted that water levels in the impoundment and elsewhere and/or flow over the spillway may have limited GZA’s ability to make observations of underwater portions of the structure. Excessive vegetation, when present, also inhibits observations. 10. In reviewing this Report, it should be realized that the reported condition of the dam is based on observations of field conditions during the course of this study along with data made available to GZA. It is important to note that the condition of a dam depends on numerous and constantly changing internal and external conditions, and is evolutionary in nature. It would be incorrect to assume that the present condition of the dam will continue to represent the condition of the dam at some point in the future. Only through continued inspection and care can there be any chance that unsafe conditions be detected. COMPLIANCE WITH CODES AND REGULATIONS 11. We used reasonable care in identifying and interpreting applicable codes and regulations. These codes and regulations are subject to various, and possibly contradictory, interpretations. Compliance with codes and regulations by other parties is beyond our control. 12. This scope of work does not include an assessment of the need for fences, gates, no-trespassing signs, repairs to existing fences and railings and other items which may be needed to minimize trespass and provide greater security for the facility and safety to the public. An evaluation of the project for compliance with OSHA rules and regulations is also excluded. COST ESTIMATES 13. Unless otherwise stated, our cost estimates are for comparative, or general planning purposes. These estimates may involve approximate quantity evaluations and may not be sufficiently accurate to develop construction bids, or to predict the actual cost of work addressed in this Report. Further, since we have no control over the labor and material costs required to plan and execute the anticipated work, our estimates were made using our experience and readily available information. Actual costs may vary over time and could be significantly more, or less, than stated in the Report. ADDITIONAL SERVICES 14. It is recommended that GZA be retained to provide services during any future: site observations, explorations, evaluations, design, implementation activities, construction and/or implementation of remedial measures recommended in this Report. This will allow us the opportunity to: i) observe conditions and compliance with our design concepts and opinions; ii) allow for changes in the event that conditions are other than anticipated; iii) provide modifications to our design; and iv) assess the consequences of changes in technologies and/or regulations. ATTACHMENT B MARKED-UP 2015 CONNECTICUT RIVER LEVEE SURVEY DRAWINGS SHEETS 1 THROUGH 8 WILLIAMS STREETHANCO C K S T R E E T EASTE R N A V E N U E LOCUS NORTHEAST SURVEY CONSULTANTS116 PLEASANT ST. SUITE 302P.O. BOX 109EASTHAMPTON, MA 01027(413) 203-5144PLAN OF LAND INNORTHAMPTON, MAPREPARED FOR THECITY OF NORTHAMPTON1 8EXISTINGCONDITIONSSH1 CT-1 CT-2 Add Centerline Stationing (typ.throughout) Add Match Lines (typ. throughout) Note surface type,i.e. Gravel Path (typ. throughout) Update extents of wooded areas,no longer wooded here (typ.throughout) Missing Inverts and rim elevations of sewer/drainage manholes and catch basins Add Rim and Invert elevation (typ.for all critical structures). Add Gate Inv.108.06 NGVD29 and add inverts of utilities penetrating system Update tree locations and tree lines, trees no longer trees here (typ.along entire levee) Add Trail Sign Add toe drain -to be provided by city Check Concrete Blocks and add elevation if still there (typ.throughout) Check Bollards and add elevation if still there (typ. throughout) Add 24"drainage pipe segments - Obtain from City General Survey Requirements: 1.Add all utilities -GIS data provided by City 2.Add Inverts of Critical Structures (i.e.Drainage Structures)-reference USACE plans provided by the City 3.Update Tree lines/Edge of wooded areas 4.Survey all encroachments within 15-feet of the toe of the levee.Typical encroachments include:Signs, Utility poles,Hydrants,Equipment,etc. 5.Add spot grades every 300 feet 6.Add Match lines 7.Add centerline stationing LOCUS VENT URERS FIEL D R O A D NORTHEAST SURVEY CONSULTANTS116 PLEASANT ST. SUITE 302P.O. BOX 109EASTHAMPTON, MA 01027(413) 203-5144PLAN OF LAND INNORTHAMPTON, MAPREPARED FOR THECITY OF NORTHAMPTON2 8EXISTINGCONDITIONSSH2 CT-3 CT-4 Note surface type,i.e. Asphalt (typ.throughout) LOCUS VENTURERS FIELD ROADVENT URERS FIEL D R O A D LOCUS NORTHEAST SURVEY CONSULTANTS116 PLEASANT ST. SUITE 302P.O. BOX 109EASTHAMPTON, MA 01027(413) 203-5144PLAN OF LAND INNORTHAMPTON, MAPREPARED FOR THECITY OF NORTHAMPTON3 8EXISTINGCONDITIONSSH3 CT-5 CT-4 Area no longer wooded Update -Gates repalced with concrete blocks *'04;564''6*'04;564''6LOCUSVENTURERS FIELD ROADINTERSTATE 91NORTHEAST SURVEY CONSULTANTS116 PLEASANT ST. SUITE 302P.O. BOX 109EASTHAMPTON, MA 01027(413) 203-5144PLAN OF LAND INNORTHAMPTON, MAPREPARED FOR THECITY OF NORTHAMPTON4 8EXISTINGCONDITIONSSH4 CT-6 CT-7 INTERSTATE 91HEN R Y S T R E E T LOCUS NORTHEAST SURVEY CONSULTANTS116 PLEASANT ST. SUITE 302P.O. BOX 109EASTHAMPTON, MA 01027(413) 203-5144PLAN OF LAND INNORTHAMPTON, MAPREPARED FOR THECITY OF NORTHAMPTON5 8EXISTINGCONDITIONSSH5 CT-8 Survey new Gates Survey and add material type Confirm limits of wooded areas (typ.) INTERSTATE 91LOCUS NORTHEAST SURVEY CONSULTANTS116 PLEASANT ST. SUITE 302P.O. BOX 109EASTHAMPTON, MA 01027(413) 203-5144PLAN OF LAND INNORTHAMPTON, MAPREPARED FOR THECITY OF NORTHAMPTON6 8EXISTINGCONDITIONSSH6 CT-9 CT-10 LOCUS INTERSTATE 91U.S. ROUTE 5 - PLEASANT STREETLOCUS NORTHEAST SURVEY CONSULTANTS116 PLEASANT ST. SUITE 302P.O. BOX 109EASTHAMPTON, MA 01027(413) 203-5144PLAN OF LAND INNORTHAMPTON, MAPREPARED FOR THECITY OF NORTHAMPTON7 8EXISTINGCONDITIONSSH7 CT-10 CT-11 CT-12 CT-13 Survey Monitoring Pins on top of Floodwall Sruvery existing grade,levee raised 6- inches since last survey LOCUS LOCUS DIKE ROADU.S. ROUTE 5 - PLEASANT STREETLOCUS NORTHEAST SURVEY CONSULTANTS116 PLEASANT ST. SUITE 302P.O. BOX 109EASTHAMPTON, MA 01027(413) 203-5144PLAN OF LAND INNORTHAMPTON, MAPREPARED FOR THECITY OF NORTHAMPTON8 8EXISTINGCONDITIONSSH8 CT-13 CT-14 Update Abandoned Water line -leave on plan but make note that it is abandoned Survey granite curb,sidewalk,and gaurdrail -recent improvements perfomred Survey aspahlt Survey 3-foot diameter manhole covers and new water main Survey Top of Concrete Headwalls