Washington County Stormdrain and BMP Characterization

Description
NPDES MS4 Phase II GIS Development – The NPDES Municipal Separate Storm Sewer System (MS4) Phase II general permit requires SHA to identify all infrastructure that captures, treats and conveys stormwater runoff from SHA facilities such as roadways, shops, district offices, welcome centers and park ‘n rides including hydraulic structures and stormwater management facilities. Greenhorne & O’Mara (G&O) will conduct MS4 GIS development for SHA ROW within Washington County. MS4 GIS Development includes:


 * GIS development for BMPs, stormdrains, hydraulic structures (inlets, manholes) cross culverts and outfalls;
 * Stormwater BMP inspections;
 * Outfall stability inspections for Major Outfalls (36” or greater diameter);
 * Storm Drain (pipe just upstream of the outfall)
 * Outfall Inspections o Number of NPDES outfalls screened for IDDE,
 * Major outfall (36” or greater or 12” or greater in hotspots) illicit discharge detection and elimination (IDDE) screening;
 * Immediate reporting to SHA if illicit discharges are discovered;
 * Developing IDDE reports for suspected illicit discharges that will allow SHA to immediately report and seek to eliminate the illicit discharge connections,
 * Monthly updates with invoices,
 * Information for annual report (due by end of April each year for compiling and delivery to MDE in May):
 * Number of NPDES outfalls screened for IDDE
 * Reports for IDDE,
 * Map and written summary of Source ID and Inspection Efforts,
 * Written summary on GIS Development,
 * Schedule with progress,
 * Other information that becomes apparent as progress proceeds

Stormdrain Numbering Procedure
This is a step process and performs accordingly:


 * 1) Pick the section or roads for which the numbering needs to be done.
 * 2) Choose all the Contracts of that road. There may be multiple contracts and some contracts may overlap.
 * 3) Have all the overlaps contract for that road available with you. Find the area that overlaps, draw a box with highlight pen to the overlap area on all the contracts, and mention the area overlaps with what contract (Contract Number).
 * 4) Do not use different number for the structure which exists in multiple contracts. (Need to be very cautious for this type of the situation). Use the latest contract to number the structure.
 * 5) Once the above procedures accomplished, start numbering the structures and pipes.
 * 6) Structure Numbering Criteria—
 * 7) * System should be a closed drainage system
 * 8) * Use seven digits numbers (2100001.004), starts with county code (i.e., Washing County Code 21), the remaining 5 digits (i.e., 00001) are generated to be unique for each system, and (.004) indicated the 4th structure of the system. The last structure will always be .001.
 * 9) * Ditch intersection (ID) can only be numbered and inventoried in two conditions, if the ditch has bottom width ≥ 2 feet or if the ditch flows in to the BMP as a part of storm drain system outfall.
 * 10) If SHA received or flows into privately owned and maintained system, the first or last structure in the private system is numbered and inventoried.
 * 11) A BMP facility may have multiple systems draining into it, in this case; use different numbering for each system. For example see the figure below.

Traning Presentation

Stronmdrain numbering procedure was discussed on this traing with EA Engineering and RAM Consultants.

Number Tracking System
Please use the table below to update the structure number are in use. This will help others not to duplicate the numbers. The table needs to be updated as you go and use new Structure Numbers.