MS4 Storm Water Outfall Inventory Advanced Outfall Tracking System (AOTS)
The Advanced Outfall Tracking System (AOTS) is a GIS application with a central database that holds field-collected spatial data associated with mapped outfalls. It is the system TxDOT uses to track compliance with the Texas Pollutant Discharge Elimination System (TPDES) permit requirements related to our Municipal Separate Storm Sewer System (MS4).
The system is used to track:
- Outfall locations
- Illicit discharge inspections
- Follow-up inspection of outfalls
- Collection of representative stormwater samples
- Physical observation and chemical data screening.
- Outfall location classifications
Additional functions include the display of:
- Spatial locations of outfall points
- Images associated with each outfall
- Map tips
Dry weather screening points are chosen based on the tracking system and discharge areas and routes.
MS4 outfall map and reporting
Using AOTS, TxDOT compiles reports and a storm sewer outfall map that contains the elements required under MS4 permits. The AOTS stores data associated with field inspections, follow-up investigations, and third-party/off-site information. The stored data can be accessed via internal storage system and additionally through a Bing maps web application with links to storm water survey databases.
The website provides dynamic mapping capabilities and near real-time tracking of information related to Agency outfalls within individual districts and across the entire state of Texas.
Illicit Discharge Detection and Elimination Program (IDDE)
The AOTS is designed to detect and report illicit discharges that occur within TxDOT’s MS4-permitted areas. TxDOT has developed the TxDOT Illicit Discharge Detection and Elimination (IDDE) Pocket Guide to aid in field inspections. The guide contains the “Outfall Field Inspection Work Flow Diagram and Classification Scheme” to assist the user in determining if the inspected outfall should be considered an illicit discharge.
Additionally, TxDOT has developed an illicit Discharge Discharge Detection and Elimination (IDDE) poster for facilities to help spread awareness.