New Standards and Regulations
GESC Manual, Stormwater Management Manual (SMM) Chapter 14 & Maintenance Agreement
The SEMSWA Board of Directors adopted a new Grading, Erosion and Sediment Control (GESC) Manual* and a revised Chapter 14, Stormwater Quality, of the Stormwater Management Manual (SMM) at their Public Hearing held on June 26, 2019.
2019 GESC Manual
The Grading, Erosion and Sediment Control Manual describes the permitting program adopted by SEMSWA to promote environmentally sound construction practices in the City of Centennial through implementation of a GESC Permitting Program that meets SEMSWA’s MS4 Permit Construction Sites Program. Arapahoe County has a similar GESC Manual to manage sediment and waste controls at their construction sites.
SEMSWA and the County determined that utilizing the same GESC Manual would increase efficiencies with construction site plan preparation and review, permitting, inspection, enforcement, and close-out. The efficiencies for SEMSWA staff managing the GESC Permit Program the same in the City and County, and the benefit to the development community and to contractors to have the same requirements, were the overarching goals of this revision process.
The revised 2019 GESC Manual reflects many months of collaboration to achieve a manual that works effectively for SEMSWA, the County, and the regulated community, and provides a Construction Sites program that mitigates pollutants from land disturbing activities in the SEMSWA Service Area.
Chapter 14, Stormwater Quality
SEMSWA’s MS4 Permit has a Post-Construction Stormwater Management/or New Development and Redevelopment program that requires the design and installation of permanent water quality Control Measure facilities that treat stormwater from a site after construction is complete. The SEMSWA Stormwater Management Manual (SMM), specifically Chapter 14, Stormwater Quality, contains the requirements on the developer team for the design, installation, and long-term maintenance for these facilities.
SEMSWA and the County have prepared a stand-alone Post-Construction Stormwater Management / New Development and Redevelopment Implementation Document that will meet the MS4 Permit requirements. The Implementation Document contains a revised SMM Chapter 14 that will be utilized by both SEMSWA and the County to meet MS4 Permit requirements. The remaining SMM chapters are now in the review and revision process so that all stormwater management practices in the City and County can be administered in a similar manner. Since some of the other SMM chapters address the process for review and approval of these permanent water quality facilities, the variance request process to deviate from the requirements, and other procedures to ensure that the permanent water quality Control Measure facilities are installed per the design and capable of long-term functionality, these “Administrative Requirements” are also contained in the Implementation Document to assist the design engineer with one reference manual for post-construction water quality facilities.
The efficiencies for SEMSWA staff managing the Post-Construction Program’s review/comment, permitting, inspection, enforcement, and facility final acceptance processes the same in the City and County, and the benefit to the development community and to contractors to have the same requirements, were the overarching goals of the SMM Chapter 14 revision process. Additionally, a Phase Ill Drainage Report and Plan Design Checklist and Standard Control Measure Details have also been revised as part of the SMM: Chapter 14 revision process.
Water Quality Facility Maintenance Agreement
A critical component of the Post-Construction Stormwater Management for Development and Redevelopment Program of the MS4 Permit is ensuring the long-term maintenance of these permanent water quality Control Measure facilities so that they function as designed to treat urban pollutants. The legal mechanism to ensure the long-term functionality of the facility is the Maintenance Agreement (MA) executed with the Owner for each site with a permanent water quality facility.
The revised MA will continue to require the owner and all subsequent owners to maintain the functional elements of the permanent water quality Control Measure facility in perpetuity such that the facility functions in accordance with the approved design. However, SEMSWA has removed the requirement of owner/operator self-inspection reporting to SEMSWA annually, as this program has had varying degrees of success. Instead, SEMSWA will document the inspection of the Control Measure to ensure the functionality of the facility, with an inspection performed once a permit term, at a minimum, to meet MS4 permit requirements.
Additionally, with the adoption of the SEMSWA Enforcement Response Plan* (Resolution 18-16), specific compliance enforcement procedures that were previously contained in the MA will be instead referred to the Enforcement Response Plan*. Also, the facility legal access conditions of the MA have been clarified to make sure SEMSWA can effectively inspect to ensure its proper working condition, as well as giving SEMSWA legal means of access for the purposes of inspecting, operating, installing, constructing, reconstructing, maintaining, and repairing or replacing the Control Measure facility to the extent that the owner fails to do so, at the owner’s expense.
A Standard Operations Procedure for Inspections and Maintenance (O&M) for each Standard permanent water quality Control Measure facility have been prepared. The design engineer is responsible for the preparation of a permanent water quality facility Operations and Maintenance Site Plan. A detailed submittal checklist for the Operations and Maintenance Site Plan will be included with the Operations and Maintenance Site Plan submittal to SEMSWA. It is anticipated that the stormwater design sheet and/or landscaping plan sheet from the CDs can be utilized as a base for preparing the Operations and Maintenance Site Plan. The Maintenance Agreement and Operations and Maintenance Site Plan will be recorded against the property.
The revised MA will provide SEMSWA a means to implement an effective Post-Construction Stormwater Management in New Development and Redevelopment Program that ensures the long-term operations and maintenance of a permanent water quality Control Measure facility such that it functions in accordance with the approved design.
*Enforcement Response Plan is available upon request. Please contact SEMSWA to review a copy.
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