Construction Site Runoff Control

1. What’s a BMP? - Press the “Enter Key” to learn more about BMP’s. • Construction Site Runoff Control • While natural erosion produces nearly 30% of the total sediment in the United States, accelerated erosion from human use of land accounts for the remaining 70%. It causes $16 billion in environmental damage annually. • The most concentrated sediment released comes from construction activities including relatively minor home-building projects such as room additions and swimming pools. • Sediment in waterbodies from construction sites can reduce the amount of sunlight reaching aquatic plants, clog fish gills, smother aquatic habitat and spawning areas and impede navigation.

2. MS4’s are required to develop programs to reduce pollutants in construction site runoff. Those programs include: • Establishing and enforcing ordinances and building codes • Implementing erosion and sediment BMP standards • Set requirement to control other construction site waste • Procedural review construction site plans; including site pollution prevention plan • Review information submitted by the public • Inspect and enforcement stormwater requirements at construction sites • BMP’s or Best Management Practices • BMP’s are common sense methods for controlling, preventing, reducing or removing pollutants in storm water runoff. • BMP’s can be in the form of structural controls as well as non-structural programs. • Structural BMP controls include storm water retention basins, storm inlet filters, vegetated filter strips, and porous pavement. • Non –structural BMP programs include animal waste collection programs, litter pick-up days, storm drain stenciling programs and incentive zoning.

3. Construction Sequencing = Runoff Control Construction sequencing is a specified work schedule to coordinate timing of land-disturbing activities, installation of erosion and sediment control measures. The goal is to reduce on-site erosion and off-site sedimentation by performing land-disturbing activities and installing erosion and sediment control practices in accordance to a planned schedule. Construction site phasing involves disturbing only part of a site at a time to prevent erosion from dormant parts. Grading activities and construction are completed and soils are effectively stabilized on one part of the site before grading and construction begins on another part. It differs from the traditional practice of construction site sequencing, in which site-disturbing activities are performed initially for all or a large section of the site, leaving portions of the disturbed site vulnerable to erosion. To be effective, construction site phasing needs to be incorporated into the overall site plan early on.

4. Erosion Control & Sediment Control Site stabilization doesn’t just begin or stop during the construction phase, it is ongoing. Erosion control can take many forms and must be maintained and kept current to conditions at the site in related to construction activity as well as weather patterns or seasonal trends. Some controls measures include: Silt fence Check dams Sediment traps Filter rolls or berms Mulching, seeding & sodding These are only a few, but there are a vast number of these BMP’s implemented by the construction industry. In most instances, several BMP’s are utilized in coordination together to provide construction site control.

5. Concrete trucks are now required to only wash out in designated containment areas. Not in streets or directly on the ground. Site Inspection – What We Look For? During the initial permitting process, the permitee must include a stormwater pollution plan for the site for review. When permits are issued, the permitee becomes responsible for runoff BMP placement, inspections and reporting of all stormwater controls at the construction site. MS4’s make routine inspection visits during all phases of construction and up to completion to monitor runoff BMP conditions. Although the permitee, or their general contractor provide onsite day to day monitoring, an MS4 is to verify ordinance and code compliance. Critical areas include: Damage silt fence Street tracking Concrete wash out areas Onsite storage containment – fuel and/or cuttings Unvegetated areas – prolong periods Improperly installed BMP Illicit discharges Improperly installed silt fence resulting in illicit discharge to storm drain. Improper construction entrance, and no BMP protection. Guess where the sediment is going!

6. Post-construction Site Runoff Control Development alters landscape by increasing imperviousness (i.e. roofs, driveways, parking lots) and changing drainage patterns that increase runoff. That leads to degradation of waterbodies; increasing the occurrence of flooding. New impervious areas will lead to a variety of pollutants detrimental to water quality, like sediment, nutrients, road salts, heavy metals, pathogenic bacteria, and petroleum hydrocarbons. MS4 municipalities now require property owners and operators to include a combination of structural and non-structural BMPs and ensure adequate long-term operation and maintenance of BMPs. Often times this is referred to going green to minimize water quality impacts form the site after construction is complete. Some used today are: Eliminating Curbs and Gutters Riparian/Forested Buffer Stormwater Wetlands Green Parking Bioretention Areas, or Rain Gardens Bioretention area in a residential subdivision. Eliminate neighborhood curbs and gutter to promote infiltration of stormwater on vegetated areas such as grass-lined channel. Infiltration basins are designed to collect stormwater from impervious areas and provide pollutant removal benefits through detention and filtration.

7. Preserving Natural Vegetation The principal advantage of preserving natural vegetation is protecting desirable trees, vines, bushes, and grasses from damage during project development. Vegetation provides erosion control, stormwater detention, biofiltration, and aesthetic values to a site during and after construction activities. Other benefits of preserving natural areas are because natural vegetation