Sewer and Storm Drain Mapping & Inspection

Inventory and Mapping Sanitary Sewer System and Storm Drain Outfalls

The Town of Middletown selected Weston & Sampson to conduct an inventory and map the town’s sanitary sewer system and storm drain outfalls. The sanitary sewer mapping was performed to assist the town with planning, maintenance, management, and collections, as well as supporting GASB34 requirements. The storm drain mapping and inspection was conducted in compliance with Environmental Protection Agency (EPA) Phase II Stormwater Regulations, GASB34, and to improve the overall stormwater management operations of the town.

The sanitary sewer GIS feature datasets included sewer lines, laterals, manhole point features, and pump stations. The sewer GIS was built from approximately 500 old sewer plans provided by the town. Detailed information about each pipe and manhole was incorporated into the sewer database. Attributes included rim and invert elevations, materials, slopes, condition assessment, and date of construction. Field data collection was conducted to locate missing manholes and/or sewer lines and their attributes and included Real Time Kinematic (RTK) Global Positioning System (GPS) data collection and manhole inspection. GPS coordinates and elevations were used in conjunction with aerial photography to build the town’s GIS. At the completion of the sewer investigation project, the town had an accurate sewer map and a detailed inventory of their sewer infrastructure.

Storm drain outfall mapping and inspection consisted of locating, inspecting, and sampling each of the known town-owned storm drain outfalls during two dry-weather periods. Inspections included physically locating each of the outfalls depicted on available mapping, recording outfall characteristics, photographing, and collecting GPS coordinates. The inspection also included visual observation of flow and, if so, documenting the observed quantity and visual characteristics of the flow. Any discharge from an outfall was collected and analyzed for temperature, conductivity, pH, and bacteria. A report on the inspection and sampling program was provided to summarize the program and tabulate inspection and sampling data. Storm drain data was added to the GIS database and formatted to generate single page storm drain outfall reports for each outfall location.


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Posted in Stormwater, Water Quality / MS4 Compliance and tagged , .