Orange County NC Website
<br /> <br /> <br /> <br /> <br /> <br />July 28, 2021 <br /> <br /> <br />Mr. Christopher J. Sandt, P.E. <br />Staff Engineer <br />Orange County Planning and Inspections Department <br />P.O. Box 8181 <br />131 W. Margaret Lane <br />Hillsborough, NC 27278 <br /> <br />Re: A&O Proposal: Limited ½ PMP Study <br />Proposal for Professional Engineering Services <br />RFQ 5285 Lake Orange Erosion Control Barrier Replacement <br />Amendment No.3 <br /> <br />Dear Mr. Sandt: <br /> <br />Alpha & Omega Group is very pleased to offer professional engineering services for this project. <br />The details of our proposal are outlined in the following sections. <br /> <br />Project Understanding <br />Hydrology calculations for the Dam on file with NCDEQ were submitted to the state on <br />November 18, 2011. As part of the current approval process for the proposed spillway <br />maintenance work, NCDEQ is now requiring that the 10 year old drainage model for the ½ PMP <br />be recalculated to ensure that the dam can still safely pass the ½ PMP storm given that <br />development has taken place within the watershed over the last ten years. <br />Scope of Services <br />The items included in our scope of service are as follows: <br /> <br />Design <br />1. Using the existing drainage study compiled by Orange County Staff Engineer Kevin <br />Lindley, PE dated November 18, 2011 as a basis for our computations, we will rerun the <br />model with the up-to-date land use curve numbers. The computations will be compiled <br />using Arc GIS, Excel spreadsheets, and other hydrology software tools. <br />2. Provide a Stormwater Hydrograph Report for your review based on ½ PMP design storm <br />which outlines the probable maximum water surface elevation during the rain event. <br /> <br />Attachment D - Additional Services for Task 8 (1/2 PMP Calculations) <br />DocuSign Envelope ID: CD3EB451-5A06-4460-9B63-D70D9212E511