Change Order No 1 - Small Drainage & Design Repair - Sampson & Overlook Proj No. 118-063 - HRP Construction, Inc.

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INTER-OFFICE MEMORANDUM DEPARTMENT OF PUBLIC WORKS DIVISION OF ENGINEERING TO: Linda M. Martin, Clerk Board of Public Works FROM: Sue Ellen Doudrick, PE SUBJECT:Sampson and Overlook (Small Drainage Design and Repair)Project No. 118-063B DATE: August 4, 2020 The purpose of this project was to implement a stormwater collection solution that reduces and possibly prevents overflow of a ditch to Overlook Court and flooding the Overlook Court cul-de- sac, which overtops during heavy rain events and floods private properties. The issue has been in existence for many years. Construction began on the project in Spring 2020 and was completed earlier this summer. This memo was prepared to present in grander detail the unforeseen conditions briefly presented in the Board of Public Works Request. The project consisted of 2 major unforeseen conditions: 1. Sanitary sewer conflict ($74,343.24 roughly 33% increase) a. The sewer in Sampson jogged east towards the storm sewer and required either a shift in the proposed storm sewer or realignment of the sanitary sewer. Due to other utilities including a duct bank existing on the east side of Sampson, significant utility relocations would be required, which would yield project delays. The west side of the street contained a water main which did not leave room for a storm sewer installation. It was decided that relocating roughly 200’ of sanitary sewer would be the best option. Due to assumptions made in the sewer alignment by the surveyor, there was no anticipation of the sewer being in conflict. The conflict was not discovered until potholing was performed during construction. The new sanitary sewer now allows for sewer video inspection equipment to be utilized as the bend in the sewer did not allow for a camera to get thru. 2. Storm sewer and channel conflicts/issues ($48,115.67 roughly 21% increase) a. It was discovered that no erosion control was planned for the storm channel construction. To maintain and preserve the seeding that would be installed in the channel, it was decided to add erosion control matting into the project (less than $1,200). b. During construction of the storm sewer, the planned doghouse/saddle manhole north of Overlook Court had to be altered as the existing storm sewer we were intercepting was not round but elliptical shaped and required alterations to the manhole. Survey by the consultant indicated a round storm sewer. ($3,500) c. Quantity overruns occurred for various items. The major items include: clearing \\\\COSB-FS1\\Share\\Public Works\\Projects\\Projects by Year\\2018 Projects\\118-063 Small Drainage Design and Repair\\PROCUREMENT\\AGENDA REQUESTS\\Memo to BPW - Sampson and Overlook Change Order Background.doc