TEN ELEMENTS OF AN EFFECTIVE STORMWATER SITE PLAN FIND YOUR LOCAL BRANCH CALL 800.944.8322 OR VISIT WhiteCap.com Plan review staff should check site plans to ensure they address common, critical elements. The following points (adapted from Brown and Caraco, 1997) present a comprehensive approach to addressing construction site runoff. 1 MINIMIZE CLEARING AND GRADING Construction site operators should take all measures possible to avoid clearing or grading stream buffers, forest conservation areas, wetlands, springs and seeps, highly erodible soils, steep slopes, environmental features, and stormwater infiltration areas. In addition, site fingerprinting should be employed and limits of disturbance (LOD) should be mapped, clearly delineated on site with flags, and conveyed to personnel. 2 PROTECT WATERWAYS Construction site operators should identify bodies of water on site and adjacent to the site. If construction activities occur near a waterbody, clearing/grading activities should be minimal and silt fencing and/or earthen dikes should be installed. 3 PHASE CONSTRUCTION Prior to construction initiation, activities should be broken into phases. Grading activities should be limited to the phase immediately under construction to decrease the time soil is exposed, decreasing the potential for erosion. Additional phases should begin only when the last phase is near completion, and preferably exposed soil has been stabilized. Construction scheduling should facilitate installation of erosion and sediment control measures prior to construction start, detail time limits for soil stabilization after grading occurs, and schedule BMP maintenance. 4 IMMEDIATELY STABILIZE EXPOSED SOILS Exposed soils should be stabilized within two weeks of the onset of exposure. The long-term goal is to establish permanent vegetation after each phase of construction; however, mulch, hydroseeding, or other means of soil coverage may protect exposed soil while facilitating vegetation growth. The stormwater site plan should detail appropriate plant species to be seeded as well as weather and climatic conditions necessary for germination and successful vegetation establishment. 5 PROTECT STEEP SLOPES AND CUTS Cutting and grading of steep slopes (>15%) should be avoided wherever possible. If a steep slope exists, all water flowing onto the slope should be redirected with diversions or a slope drain. Silt fencing at the top and toe of the slope must be anchored well, although this measure may not provide adequate protection by itself. On steep slopes, jute netting and erosion control blankets (geotextiles) should be used in conjunction with seeding or mulching, as seeding alone may not be effective. 6 INSTALL PERIMETER CONTROLS Silt fence should be properly installed around the perimeter of the construction site. A fiber roll on the inside (site-facing) of the fence works to provide additional filtration. In areas of heavy flows or breech concern, a properly sized earthen dike with a stabilized outlet should be created. In addition, catch basin inlets receiving stormwater flows must be protected with adequate inlet controls. 7 ADVANCED SEDIMENT SETTLING CONTROLS Sediment Basins should be created where space is available; however, discharge from basins must be non-turbid. The use of skimmers and multiple cell construction of basins assist in sediment drop-out. 8 CERTIFY AND TRAIN CONTRACTORS Contractors and/or construction staff should be trained in erosion and sediment control features. Meetings and site inspections by municipal staff provide opportunities for discussion of effective BMPs with site staff. Inspectors should make a strong commitment to contractor education to develop a constructive and responsive relationship. 9 CONTROL WASTE AT THE SITE The site plan should describe the type of construction site waste found at the site, such as discarded building materials, concrete truck washout, chemicals, litter, and sanitary waste, and how that waste will be controlled to minimize adverse impacts to water quality. For example, concrete washout and trash storage areas should be clearly labeled on the plan and should be located away from waterbodies and catch basin inlets. INSPECT AND MAINTAIN BMPS Each stormwater site plan should clearly describe the construction site operator’s BMP inspection and maintenance, including who will inspect the site and how often. Ideally, an example inspection form should be included with the plan. Inspections should occur at a regular interval and should also occur immediately before and after rain events. The plan should also describe how BMPs will be maintained. 10 Scan the QR code to learn more about best practices .
