Stormwater GIS Data Development Screening and Reporting Services

Civil/environmental engineering and geographic information system consultants to develop and standardize the Town’s municipal separate storm sewer system data and to perform required outfall screening, monitoring, documentation, and annual reporting support under Connecticut’s MS4 program.
- GIS environment.
1. Project initiation and data audit. Conduct a kickoff meeting; inventory existing Town GIS layers, scanned plans, as-builts, prior sampling records, reports, and relevant DEEP and CTDOT data; document coordinate systems, schemas, data quality, gaps, and recommended priorities.
2. Data model and standards. Propose and obtain Town approval of a commonly used, open, Esri-compatible geodatabase schema, domains, unique identifiers, metadata, naming conventions, quality-control rules, and update procedures.
3. Existing data standardization. Clean, normalize, and migrate current structures and pipe data; parse dimensions and materials from notes into fields; remove or flag duplicates; preserve source and confidence information; and segment pipes at structure nodes while retaining correct connectivity and flow direction.
4. Desktop data development. Digitize available sewer, drainage, road, subdivision, record, and scanned plans; review current aerial imagery; identify apparent missing catch basins, culverts, conveyances, structures, treatment systems, and outfalls; and flag features requiring field verification.
5. Outfall and interconnection inventory. Identify and map Town outfalls and interconnections with CTDOT, adjoining municipalities, institutions, private systems, and other known stormwater systems. Each feature shall have a unique identifier and relationship to its upstream catchment and downstream receiving water.
6. Field verification and collection. Perform targeted GPS-enabled field work, beginning with impaired waters, urban areas, high impervious cover, and other priority catchments. Record field observations and photographs in real time and document horizontal accuracy and collection method.
7. Catchments and receiving waters. Delineate or associate outfall catchments to the extent feasible; assign receiving-water name and identifier, watershed or subregional basin, impairment status, pollutant of concern, TMDL status, and priority category.
8. Dashboard and field tools. Configure a Town-accessible dashboard and mobile field forms that track mapped assets, data completeness, outfalls screened, samples, results, follow-up investigations, annual monitoring, and reporting status. User permissions and editing workflows shall be documented.
9. Quality assurance and handoff. Conduct topology, connectivity, completeness, attribution, and positional checks; provide a data-gap and priority map; deliver all data, attachments, photographs, forms, dashboards, configurations, metadata, and documentation; and train designated Town staff.