SECTION 4 Stormwater Quality, Erosion, and Sediment .Stormwater Quality, Erosion, and Sediment

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Text of SECTION 4 Stormwater Quality, Erosion, and Sediment .Stormwater Quality, Erosion, and Sediment

  • 4-1


    Stormwater Quality, Erosion, and Sediment Control

    4.1 Introduction The City has been identified by ADEM as an NPDES Stormwater Phase II community. One requirement of the Phase II program is to develop and implement a stormwater management program for construction and post-construction conditions. This section of the Manual is designed to provide resources to local agencies, engineers, developers, or others involved in erosion control and stormwater management in the City for helping to meet the NPDES Phase II requirements.

    4.1.1 Erosion and Sediment Control Construction activities typically require the stripping of vegetation and/or removal of other existing stabilization from the ground surface, which exposes soil to rainfall energy and runoff velocities. As a result, significant soil erosion from construction sites can occur. The yield of soil erosion products from a construction site will depend on soil characteristics, climatic conditions, ground topography, and other site-specific factors. For this reason, varying amounts of sediment and turbidity will be generated and have a potential to discharge to Waters of the State, potentially violating State of Alabama Water Quality Standards. Sediment also can cause adverse impacts to offsite drainage conveyances and roads.

    Construction activities that have the potential to affect the environment include, but are not limited to, land disturbance or discharges of pollutants associated with building, excavation, land clearing, grubbing, placement of fill, grading, blasting, reclamation, areas in which construction materials are stored in association with a land disturbance or handled aboveground; and other associated areas including, but not limited to, construction site vehicle parking, equipment or supply storage areas, material stockpiles, temporary office areas, and access roads. Construction activities of concern also include significant preconstruction land disturbance activities performed in support of NPDES construction activity including, but not limited to, land clearing, dewatering, and geotechnical investigations.

    To protect water quality and to comply with the ADEM NPDES regulations (ADEM Admin. Code R. 335-6-12) and the Citys Erosion and Sediment Control Ordinance (ESC Ordinance), effective and applicable BMPs must be fully implemented to the maximum extent practicable. The operator must remediate any adverse impact that is caused by ineffective BMPs to maintain compliance with the requirements.



    4.1.2 Post-development Stormwater Quality Management Once completed, land development projects can have a long-lasting impact on water quality caused by the discharge of pollutants to nearby watercourses. These pollutants vary in type and concentration from place to place; but certain pollutants such as total suspended solids (TSS), petroleum-based contaminants, phosphorus, nitrogen, heavy metals, and fecal coliform bacteria are of particular concern. Water quality issues related to these non-point source pollutants generally are addressed through the implementation of post-development water quality BMPs. Various types of BMPs, as well as the benefits and drawbacks of each type and the methods to select them to address particular site concerns, are included in this section of the Manual.

    The Manual will serve as a guide for city staff, consultants, and citizens to achieve consistency in the design and compliance of stormwater projects so that both growth and environmental guidelines can be followed effectively. Incorporating the guidelines contained in this Manual into applications and permits will aid in obtaining construction permits from the City.

    4.1.3 Importance of Compliance Full compliance with both ADEM Phase II Stormwater regulations and the Citys ESC Ordinance are required to protect the quality of water and the quality of life in the Auburn area. Any noncompliance with the requirements constitutes a violation and is grounds for potential enforcement actions by ADEM, U.S. Environmental Protection Agency (EPA), and/or the City. An enforcement action could include, but not be limited to, a warning letter, notice of violation, consent or administrative order with monetary penalty, civil or criminal litigation, monetary fines imposed by the City, or an order to stop work on the site. In addition, holds may be placed on City Code inspections if erosion control measures are found to be non-compliant.

    The ADEM Phase II Stormwater Regulations require that the stormwater runoff from construction activities be protective of water quality to the maximum extent practicable. To accomplish this goal, the regulations require that all site operators of NPDES Construction Sites develop and fully implement and maintain effective and applicable BMPs.

    NPDES Construction Sites are construction activities that are required to obtain NPDES permit coverage under the ADEM regulations and are defined as the following:

    Construction activities with land disturbance that will disturb 1 acre or greater

    Construction activities that will disturb less than 1 acre but are part of a larger common plan of development or sale whose land-disturbing activities total 1 acre or greater.

    Construction or maintenance activities, irrespective of size, whose stormwater discharges have a reasonable potential to be a significant contributor of pollutants to a Water of the State, or whose stormwater discharges have a reasonable potential to cause or contribute to a violation of an applicable Alabama water quality standard as determined by a Qualified Credentialed Professional (QCP) or ADEM.



    Construction activities that will disturb less than 1 acre may not be required to obtain NPDES permit coverage, but are still required to implement the appropriate BMPs to protect water quality.

    The continual assessment of the compliance status of an NPDES Construction Site is the responsibility of the construction site NPDES permit holder. This is accomplished through the full implementation of the Construction Best Management Practices Plan (CBMPP) and the inspection and maintenance activities required by the ADEM regulations and the Citys ESC Ordinance. These activities are discussed specifically in Section 4.3 of this Manual.

    Because ADEM has primary regulatory authority of NPDES permitting of regulated construction activities in Alabama, permitting, compliance, and enforcement are all under the ADEM NPDES jurisdiction. Permitting and enforcement are under the ADEM Water Division. The field compliance unit is under the ADEM Field Operations Division. ADEM is responsible for the protection and preservation of water quality in Alabama by regulating activities that could lead to adverse impacts on the environment.

    ADEM performs the following tasks as related to NPDES Construction Sites in Alabama:

    Review and approve or reject construction site NPDES construction stormwater permit coverage requests (Permitting Branch).

    Conduct routine compliance assurance site inspections in accordance with their guidelines (Field Operations).

    Conduct site inspections in response to citizen concerns (Field Operations).

    Review the compliance status of a construction site based on submitted documentation and field reports (Enforcement Branch).

    Issue enforcement actions when noncompliant issues are evident on the site that may result in any adverse impacts (Enforcement Branch).

    Acting in the best interest of the community, the City developed local construction site erosion and sediment control regulations (ESC Ordinance) for construction activities within the jurisdiction of Auburn. The ESC Ordinance reinforces the Auburn goal to protect and preserve the local water resources and quality of life. The City developed the ESC Ordinance as a regulatory means to manage construction sites. The original Ordinance was developed by the Auburn, Lee County, Opelika, and Auburn University (ALOA) Citizen Advisory Committee in 2002 and was adopted by the Auburn City Council in July 2002. This ordinance provides guidelines for submitting CBMPPs, as well as for documenting City inspection and enforcement procedures. The Citys policies and procedures regarding erosion and sediment control inspection and enforcement are outlined in Section 4.3.3 of this Manual.

    The City supports the ADEM permitting, compliance, and enforcement processes through the adoption of the ESC Ordinance and the Citys enforcement and site inspection efforts. The Citys response to post-storm events ensures that failed or



    deficient BMPs are corrected promptly. The City has adopted statewide standards for the design, construction, and maintenance of BMPs to provide a degree of uniformity in the requirements across the City. The City also routinely consults with ADEM to determine if there are any changes that need to be made to better support the ADEM efforts to protect the Waters of the State.

    The City has not been delegated any authority to directly develop water quality standards. These are promulgated at the state and federal levels and managed through ADEM and EPA. The City works closely with these governing agencies when there appear to be deficiencies that may have resulted in adverse water quality or environmental impacts, as well as to learn ways to improve the Citys program to support the Auburn area. Protecting Water Quality during Construction It is the responsibility of the developer or operator to retain or employ a qualified professional to design all aspects