STORMWATER MANAGEMENT

Transcription

1 STORMWATER MANAGEMENT What is Stormwater? Stormwater in Southwest Louisiana is generally water resulting from rain that runs off surfaces such as rooftops, paved streets, highways and parking lots. Along the way, the water may pick up and transport contaminants including motor oils, gasoline, antifreeze, and brake dust (commonly found on pavements), fertilizers and pesticides (found on landscaped areas), and soil sediments (from farms and construction sites). The water eventually flows into a local stream, river or lake, or into a storm drain and continues through storm pipes until it is released untreated into a local water body. During the construction process, soil is the most vulnerable to erosion by wind and water. This eroded soil endangers water resources by reducing water quality, and causing the siltation of aquatic habitat for fish and other desirable species. Eroded soil also necessitates repair of sewers and ditches, and the dredging of lakes. In addition, clearing and grading during construction causes the loss of native vegetation necessary for terrestrial and aquatic habitat, and may be necessary to provide a healthy living environment for citizens of Lake Charles, as well as our neighbors. The intent of the Stormwater Management is to: Minimize water pollution by providing guidance on how to protect storm drain inlets and waterways during construction activities from grading, utility construction, millings/grinding operations, concrete saw water, waste materials such as concrete washout, and any disturbances to dirt/earth. Protect as much existing vegetation as possible, slow down runoff, prevent or minimize erosion from construction activities, provide incremental phased seeding and mulching, avoidance and minimization, stabilization, implementation, seeding and scheduling of the plan. Stabilize earth disturbances; prevent sediment from reaching the receiving or surface waters. 1

2 Urbaniza on increases the variety and amount of pollutants carried into our na on's waters. In urban and suburban areas, much of the land surface is covered by buildings, pavement and compacted landscapes with impaired drainage. These surfaces do not allow rain and snow melt to soak into the ground which greatly increases the volume and velocity of stormwater runoff. In addi on to these habitat destroying impacts, pollutants from urban runoff include: Sediment Oil, grease and toxic chemicals from motor vehicles Pes cides and nutrients from lawns and gardens Viruses, bacteria and nutrients from pet waste and failing sep c systems 2

3 Pollution Prevention Around the House Correctly dispose of chemicals Do Not Dump! Incorrect disposal of hazardous chemicals is extremely harmful to people, pets and the environment. To dispose of household hazardous waste, such as drain cleaner, pool chemicals, aerosol products, paint thinner, and many others contact Team Green: TEAM GREEN SOUTHWEST LOUISIANA (SWLA) Business Phone: Business Fax: Team Green of Southwest Louisiana host numerous opportunities throughout the year that help the residents of SWLA environment. These events include but are not limited to: Recycling, Adopt-A-Spot/Litter Pick-up, Mercury Collection, Beach Sweep, Clean Campus Contest, and Telephone Book Recycling Contest, just to name a few. For interested volunteers or more information, please call Team Green of SWLA or goteamgreenswla@cityoflc.us Use only phosphorus-free (P-Free) fertilizers on the lawn: If you fertilize the lawn, be sure to use only phosphorus-free (P-Free) fertilizer. If a spill occurs, clean it up using a broom, rather than a hose, because the water will make its way into stormwater drains. Excess phosphorus in our waterways creates algae blooms and oxygen depletion in our lakes and ponds. Check vehicles for leaks, and fix them: If you notice your car is leaking fluid, be sure to fix the problem immediately. Instead of using water to wash away the spill, use a substance such as kitty litter to absorb the spill, and prevent it from polluting our waterways. To dispose of hazardous chemicals such as anti-freeze contact Team Green of Southwest Louisiana. Washing the Car: Dirty water contains soaps and detergents; gas and oil; residues from exhaust; and heavy metals. Instead of washing the car in the driveway or street, which allows these pollutants to enter the water system, take it to a car wash. Car washes are required to send the water to a treatment plant before it enters the waterways. As an alternative, wash your vehicle on the lawn - the soil will filter out many of these pollutants and slow the entry process into the storm drains. On the Street: Keep storm drains clear of litter and debris: To allow water to efficiently flow through the storm drains, be sure that the drain is clear of litter and other debris. Pick up after your pet: Pet waste is a major contaminant of our waterways. Be sure to always pick up after your pet! Keep grass clippings in your yard: It is against City Code to blow grass clippings from the mower into the street. Aim your lawnmower discharge back towards your lawn. This will keep the grass from clogging storm drains and provide natural fertilizer to your lawn. 3

4 Construction Stormwater Runoff Management During the construction process, soil is the most vulnerable to erosion by wind and water. This eroded soil endangers water resources by reducing water quality, and causing the siltation of aquatic habitat for fish and other desirable species. Eroded soil also necessitates repair of sewers and ditches, and the dredging of lakes. In addition, clearing and grading during construction causes the loss of native vegetation necessary for terrestrial and aquatic habitat, and may be necessary to provide a healthy living environment for citizens of Lake Charles, as well as our neighbors. 4

5 Best Management Practices (BMP) Construction Sites All operators of construc on sites shall use best management prac ces to control and reduce the discharge, to the MS4 and to waters of the United States, of sediment, silt, earth, soil, and other material associated with the clearing, grading, excava on, and other construc on ac vi es to the maximum extent prac cable. Such best management prac ces may include, but not be limited to, the following measures: Ensuring that exis ng vegeta on is preserved where feasible and that disturbed por ons of the site are stabilized as soon as prac cable in por ons of the site where construc on ac vi es have temporarily or permanently ceased. Stabiliza on measures may include: temporary seeding, permanent seeding, mulching, geotex les, sod stabiliza on, vegeta ve Use of structural prac ces to divert flows from exposed soils, store flows, or otherwise limit runoff and the discharge of pollutants from the site to the extent feasible. Minimiza on of the tracking of sediments off site by vehicles, the genera on of dust, and the escape of other windblown waste from the site; 5

6 Preven on of the discharge of building materials, including cement, lime, concrete, and mortar, to the MS4 or waters of the United States; Providing general good housekeeping measures to prevent and contain spills of paints, solvents, fuels, sep c waste, and other hazardous chemicals and pollutants associated with construc on, and to assure proper cleaning and disposal of any such spills, in compliance with state, federal, and local requirements; Implementa on of proper waste disposal and waste management techniques, including covering waste materials and minimizing ground contact with hazardous chemicals and trash; Timely maintenance of vegeta on, erosion and sediment control measures and other best management prac ces in good and effec ve opera ng condi on. 6

7 BEST MANAGEMENT PRACTICES All operators of construction sites shall use best management practices to control and reduce the discharge, to the MS4 and to waters of the United States, of sediment, silt, earth, soil, and other material associated with the clearing, grading, excavation, and other construction activities to the maximum extent practicable. Such best management practices may include, but not be limited to, the following measures: Ensuring that existing vegetation is preserved where feasible and that disturbed portions of the site are stabilized as soon as practicable in portions of the site where construction activities have temporarily or permanently ceased. Stabilization measures may include: temporary seeding, permanent seeding, mulching, geotextiles, sod stabilization, vegetative buffer strips, protection of trees, preservation of mature vegetation, and other appropriate measures; Use of structural practices to divert flows from exposed soils, store flows, or otherwise limit runoff and the discharge of pollutants from the site to the extent feasible; Minimization of the tracking of sediments off-site by vehicles, the generation of dust, and the escape of other windblown waste from the site; Prevention of the discharge of building materials, including cement, lime, concrete, and mortar, to the MS4 or waters of the United States; Providing general good housekeeping measures to prevent and contain spills of paints, solvents, fuels, septic waste, and other hazardous chemicals and pollutants associated with construction, and to assure proper cleaning and disposal of any such spills, in compliance with state, federal, and local requirements; Implementation of proper waste disposal and waste management techniques, including covering waste materials and minimizing ground contact with hazardous chemicals and trash; Timely maintenance of vegetation, erosion and sediment control measures and other best management practices in good and effective operating condition; and Installation of permanent structural measures during the construction process to control pollutants in storm water discharges that will occur after construction operations have been completed (post-construction). These structural measures should be placed on upland soils to the degree attainable. Such installed structural measures may include, but not be limited to, the following: storm water detention structures (including wet ponds); flow attenuation by use of open vegetative swales and natural depressions; other velocity dissipation devices, infiltration of runoff on site; and sequential systems which combine several practices. Operators of construction sites are only responsible for the installation and maintenance of permanent storm water management measures prior to final stabilization of the site, and are not responsible for maintenance after storm water discharges associated with construction activity have terminated. Any owner of a site of construction activity, whether or not he/she is an operator, is jointly and severally responsible for compliance. Any contractor or subcontractor on a site of construction activity, who is not an owner or operator, but who is responsible under his/her contract or subcontract for implementing a best management practices control measure, is jointly and severally responsible for any willful or negligent failure on his/her part to adequately implement that control measure if such failure causes or contributes to causing the City of Lake Charles to violate a water quality standard, the City's LPDES permit, or any other stateissued discharge permit for discharges from its MS4. Based on the results of the inspections required, the site description and/or the pollution prevention measures shall be revised as appropriate, but in no case later than one (1) calendar day following the inspection. Such modifications shall provide for timely implementation of any changes to the SWPPP within seven (7) calendar days (per the state storm water general permit for small construction activities) following the inspection. The City may withhold an occupancy or use permit for any premises until final stabilization has occurred, as determined by an appropriate inspection, and that all required permanent structural controls have been completed. Any person responsible for a known or suspected release of materials which result in or may result in illegal discharges to the storm drainage system shall take all necessary steps to ensure the discovery, containment, abatement and cleanup of such release. In the event of such a release of a hazardous material, said person shall comply with all state, federal, and local laws requiring reporting, cleanup, containment, and any other appropriate remedial action in response to the release. In the event of such a release of non-hazardous materials, said person shall notify the compliance officer no later than 4:30 p.m. on the next business day. 7

8 Grading Plan Required A Stormwater Grading Plan will be required for any soil disturbance during property clearing, adding fill or grading for small construction projects and/or large developments that change existing stormwater flow. Various construction activities are: portable and non-portable accessory building foundation, swimming pools, new driveways or parking areas, lot clearing, removal/importing or grading dirt, or any activity where the stormwater runoff affects adjacent property owners or outflows into the storm drains. 8

9 GRADING PLAN EXAMPLES 9