Storm Water Pollution Prevention Plan Development Todd E. Hubmer PE WSB & Associates hubmer@wsbeng.com

How to develop a SWPPP Description of the project Description of how storm water and erosion will be manage on-site Includes narrative, erosion control plan sheets, standard details Drainage map, soils map, ponding calcs

SWPPP Components Ponding must treat 0.5” of runoff from new impervious surface for entire subwatershed Wet basin, Regional pond, Combination, or Alternative method (rain garden, etc.; requires 90 day review by MPCA) Road projects: fit in ponding if you can. If cannot fit in, other options (grassy swales, rock checks grit chambers, etc.) should be used The handout is included on the course guide disk, entitled, “NPDES Phase II Construction Permit Info.doc” This handout should be updated to reflect the most current requirements for the NPDES Phase II permit. We also prepared a copy of the current NPDES Phase II permit, and distributed it as part of the course notes. That permit can be downloaded in its most up-to-date version.

Inspections and Maintenance NPDES requires inspection Every 7 days Within 24 hours of a 0.5 inch-24 hour rainfall event Once a month for areas that have undergone final stabilization (but work is ongoing in other areas) See PCA calendar

Inspections and Maintenance Inspection and maintenance must be recorded in writing and include: Date and time Name of inspector Findings and recommendations Corrective actions taken Date and amount of rainfall >0.5” in 24 hrs Documentation of changes in SWPPP

Penalties/Enforcement PCA will be increasing enforcement SWCD’s, Watershed Districts can be authorized agents for PCA You will need to produce the SWPPP and inspection reports Penalty for non-conformance is $10,000 per day per violation Erosion Control Jail

Erosion Control BMP’s Required by NPDES

INLET PROTECTION

MAINTENANCE OF SILT FENCE OR IF ADDITIONAL BMP’S MAY BE REQUIRED GEOTEXTILE FABRIC

ROCK CONSTRUCTION ENTRANCE TO REDUCE SEDIMENT TRACKED OFF SITE

FINAL STABILIZATION

DESIGNATED WASH-OUT SITE

CATEGORY 1 BLANKET, TEMPORARY SEED, AND SILT FENCE MAINTENANCE AFTER CATEGORY 1 BLANKET, TEMPORARY SEED, AND SILT FENCE MAINTENANCE

Sediment tracked off site or on streets must be removed with 24 hours

Silt fence repaired, replaced when down or sediment reaches 1/3 height of fence w/i 24 hours

Other NPDES requirements Silt fence repaired, replaced when down or sed reaches 1/3 height of fence w/i 24 hours Temp and perm basins must be drained and cleaned out when ½ storage volume is gone w/i 72 hours Sed deltas, filled CB’s, filled ditches must be cleaned/stabilized w/i 7 days Sed tracked off site must be removed with 24 hours

Other NPDES requirements If sed in lakes, wetlands, streams, stabilize area upstream and remove sed w/i 7 days Hazardous materials stored appropriately No dumping of oil, junk, etc Garbage must be disposed of properly Once site has undergone final stabilization, NOT submitted

Other inspection requirements Seeding timeline w/i 200 feet of surface water Slope steeper than 3:1 – 7 days Slope 10:1 to 3:1 – 14 days Slope flatter than 10:1 – 21 days Surface water is stream, lake, wetland, ditches, ponds, whether natural or artificial. Stockpiles need silt fence Riprap at pipe ends w/i 24 hours of connecting Dewatering – Water must be directed to storm water pond or treated before discharge

Questions?