County hires Goodwin Mills and Caywood for sewer-modeling study; $80,000 contract covers Harlem model and system gaps analysis

Columbia County approved an $80,000 independent-contractor agreement with Goodwin Mills and Caywood to develop a sewer model for the city of Harlem and perform a system gaps analysis as phase 1 of a multi-step approach toward a countywide water and sewer model.

Public Works staff explained the county completed a water model during a previous master plan but deferred a sewer model to reduce costs. The current contract funds a focused sewer model for Harlem and a desktop gaps analysis for the remainder of the system, enabling county staff to gather needed field data in stages rather than contracting full wet-weather flow monitoring across the entire system.

Staff described a wet-weather model that requires flow-monitoring equipment in sewers as expensive — potentially approaching three-quarters of a million dollars for the whole system — and said the county plans to use “smart covers” and in-house monitoring where practicable to estimate inflow and infiltration (I&I). Goodwin Mills and Caywood will complete the dry-weather model component and identify data gaps the county must fill before a full system model is complete. The county intends to fund the work from the engineering department's general operating fund.

Staff recommended approval of the $80,000 contract. Commissioners approved the item on consent.

The project is intended to produce a completed water and sewer model ahead of the county's next comprehensive master plan; the contract represents phase 1 of that effort. The record does not provide a detailed timeline for deliverables or specific milestones for in-house data collection.