Post Construction and Redevelopment Inspection Manual

Transcription

1 City of Myrtle Beach Post Construction and Redevelopment Inspection Manual In April 2003, the United States Environmental Protection Agency (USEPA) issued a National Pollutant Discharge Elimination System (NPDES) General Permit for Stormwater Discharges from Small Municipal Separate Storm Sewer Systems 1 (MS4s). Over 70 South Carolina communities have now become subject to Stormwater Phase II regulations based on their designation as Urbanized Areas according to the 2000 US Census. The City of Myrtle Beach currently sponsors the Coastal Waccamaw Stormwater Education Consortium (CWSEC), which supports public outreach activities aimed towards minimizing pollutant stormwater runoff and enhancing coastal area water quality. The City also supports an online customer service request webpage whereby citizens can submit requests for any city service, including reporting contaminant spills, asking stormwater site inspection questions, and requesting stormwater management information. Revision Date: January 14, An MS4 is defined as any conveyance or system of conveyances that is owned or operated by a state or local government entity designed for collecting and conveying storm water, which is not part of a Publicly Owned Treatment Works.

2 Table of Contents General Information... 1 Types of Stormwater Systems... 1 Stormwater System Maintenance Practices... 2 Stormwater System Inspections... 4 Drainage Plan Drawings... 4 Exempt Areas of the City... 5 Tracking System... 5 Stormwater System Inspection Field Sheets... 6 Inspection Feedback... 6 Re-inspections... 7 Appendix A: Stormwater System Inspection Field Sheets... 8 Pipe and Pond System... 8 Exfiltration System... 8 Best Management Practice (BMP) Structures... 8 Appendix B: Stormwater System Inspection Letters of Communication Letter of Correction Compliance Letter... 15

3 General Information A critical element of the National Pollutant Discharge Elimination System (NPDES) general permit is for the City of Myrtle Beach to implement a Post Construction and Redevelopment Stormwater System Inspection Program. Such a program aims to monitor the operational effectiveness of public and private stormwater systems located within the city s jurisdiction, as well as evaluate routine drainage system maintenance practices. Increased stormwater runoff compromises water quality by allowing more contaminants to enter the public stormwater system. Once a site is developed it yields a higher stormwater runoff volume that flows at a much faster rate. Flow control measures attempt to reduce the impacts of urban development by replenishing vegetated cover and pervious surfaces and retaining water onsite to help slow stormwater release rates. Unless dedicated to the city after construction, individual property owners are ultimately responsible for maintaining their private stormwater systems to ensure that they are operational and properly maintained over the long-term. The drainage systems should be routinely visually inspected every season for high sediment levels, missing or broken drainage structures, and poor drainage areas. If a drainage structure is failing or in need of repair, the property owner should contact Public Works Department staff immediately. Types of Stormwater Systems Detention systems are designed to control the discharge rate of stormwater runoff from a site by detaining flows and ultimately releasing stormwater at an approved discharge rate through a flow control structure. Common components of a detention system include a detention pipe that temporarily stores stormwater runoff, a flow control structure, and a flow control device. Storm grates that allow stormwater runoff to enter the underground drainage system. Storm grates are located over a catch basin or an inlet structure that leads directly to a storm drainage pipe. Catch basins are underground boxes that receive stormwater through a grate at ground level and/or through an inlet pipe. Stormwater discharges through an outlet pipe, usually at least three feet above the bottom of the catch basin, thus creating a sump to collect sediment and other debris. Outlet traps prevent automotive fluids and floating debris from leaving the catch basin and entering the public stormwater system. Flow control structures store water in a large underground pipe and release it slowly into the public stormwater system. They also help to store sediment and keep it from entering streams. 1

4 Conveyance systems include drainage facilities that are used to transport stormwater. Some of the most common conveyance structures are drainage pipes, swales, ditches, and canals. Exfiltration systems temporarily store and then diffuse stormwater runoff into the washed stone trench bedding and surrounding soils. A soils report is often submitted by design engineers to ensure site soil conditions will support a specified infiltration rate. Stormwater treatment systems can be biological, mechanical, or chemical treatment systems. Biological treatments systems, such as StormTreat, promote settling of sediment particles through a series of distribution channels and the biological uptake of the captured stormwater through vegetation Mechanical treatment systems such as Vortechnic units promote rapid settling of sediment particles contained in the stormwater runoff, whereas CST units, trash racks, and filter vaults simply prevent large debris from entering the stormwater system. Chemical treatment systems involve chemical dosing of the stormwater to remove target pollutants. Stormwater System Maintenance Practices Upholding a routine maintenance program for the stormwater system ensures that drainage structures operate in accordance with design standards so properties are not flooded and pollutants are not released into the public stormwater system. A good practice is for property owners to visually inspect their stormwater system once every season and routinely cut vegetation around ponds, ditches/swales, and outlet structures to eliminate poor drainage conditions. Some Key Areas for Visual Inspection of Stormwater Systems are: Oil sheen, stains, dirt or other signs of pollutants around the storm grates. Poor drainage, which may indicate a plugged outlet or drainage pipe. Sagging asphalt around catch basins. Excessive sediment in the catch basin. Insert a yardstick or other probe to see how much sediment has collected. Generally, it should be cleaned when there is less than 18-inches between the top of the sediment and the outlet pipe. Damaged or missing outlet traps. Debris around flow control structures. 2

5 Some Common Stormwater System Maintenance Practices are: Remove leaves and debris from storm grates to prevent clogging. Eliminate sources of pollutants if the presence of oil sheen, stain, dirt or other pollutant is detected. Sweep parking lots regularly to reduce the need for catch basin cleaning. Repair or replace damaged outlet traps and reattach after cleaning catch basins. Clean catch basins. If the sediment contains oil or other contaminants it should be disposed of at an appropriate site. Contact the City of Myrtle Beach sanitation department for more information. Use caution when lifting the lid of a catch basin, as it may be heavy. Do not leave an open catch basin unattended since it can become a hazard. Further, do not enter a catch basin, flow control, or other drainage structure unless you are properly trained, as confined space safety requirements may apply. 3

6 Stormwater System Inspections The Engineering Division of the Public Works Department must approve any discharges of stormwater from a site, and the discharge shall be limited to a publicly owned storm drainage pipe or a designated receiving waterbody, such as an existing ditch or lake. The land or property owner is responsible for maintaining all runoff control measures and drainage facilities/structures after site development has been completed. To maintain our high water quality standards; prevent flooding; and be in compliance with federal, state, and local stormwater regulations; the City of Myrtle Beach Public Works staff conducts random inspections of private stormwater systems located within commercial or multi-family developments. The goal of conducting these ongoing stormwater system inspections is to ensure adequate long-term operation and maintenance of drainage structures within the City of Myrtle Beach jurisdiction. Any commercial or multi-family development properties that were constructed or redeveloped after the initial passing of the stormwater management ordinance (October 15, 1985) are subject to these drainage system inspections. To better organize the inspection process, the city has been divided into post construction inspection (PCI) zones. The boundaries of these PCI zones may change at any time, and a current map of the PCI zones can be obtained from the Engineering Division. Each zone is comprised of various commercial and multi-family parcels. Property owners must provide adequate access to permit the city to inspect the drainage system on the premises and inspections will be performed by Public Works Department staff at random and without notice. The findings of stormwater system inspections will be communicated to individual property owner(s) of record in the form of a written letter, and corrective action(s), if any, will need to be taken by the property owner in a timely manner. Drainage Plan Drawings If the city does not already have a copy of the drainage plan construction or as-built drawings on file, then an effort should be made to have the property owner provide a copy at least three (3) days prior to the site inspection so the inspector may review the drainage structures prior to his/her arrival. If drainage plans cannot be obtained, then the inspector will document the private stormwater system on the property during the inspection. The newly documented private stormwater system should be added to the citywide utility map for future reference. The inspector should provide a stormwater system drawing to the Geographical Information System (GIS) Technician within the Engineering Division. The drawing should identify: Retention or detention structures Ditches or swales Closed drainage structures 4

7 o Catch basin/junction box locations and size o Diameter/Shape of pipeline o Length of pipeline o Material of pipeline o Slope (if possible) o Invert elevations (if possible) o Outfall locations (if possible) Once the GIS Technician identifies unique unit identification names for the various stormwater structures, these unit identification names will be used within the ARCVIEW 2 and HANSEN 3 software. In order to distinguish between public and private stormwater drainage systems within the HANSEN software, public drainage structures will be grouped according to their unique drainage basin (group) and stormwater maintenance zone (subgroup), while all private drainage structures will assigned to a private group (PRIV). The stormwater structures on each property will be identified as a group asset within the HANSEN software and labeled in accordance with their unique tax map identification number(s), or TMS number(s). Individual inspections will be recorded as group projects within the HANSEN software. Any digital pictures taken during the inspections will be stored within the image catalog feature of the software under the unique label of the TMS number. Exempt Areas of the City Some areas of the city where commercial and multi-family properties were developed prior to the adoption of the original Stormwater Ordinance (October 15, 1985) are considered exempt from stormwater inspection corrective activities until such a time when the property becomes redeveloped under new stormwater regulations. Public Works Department staff is currently drafting a map to illustrate properties that are considered exempt. Single family residences themselves are exempt from inspections, however private drainage systems that serve a larger common area, which are often maintained and operated by a homeowners or property owners association, are subject to drainage inspections. Tracking System The Public Works Department currently uses HANSEN to track street and drainage maintenance activities. The Street and Drainage Superintendent and Stormwater 2 ARCVIEW is a software product offered by ESRI that is essentially a desktop GIS for mapping, data integration, and analysis. 3 HANSEN is a government solutions software product offered by Hansen Information Technologies that is essentially a multifaceted infrastructure management software application. 5

8 Technician both record stormwater system inspection activities within the HANSEN program as work orders or group projects. Stormwater system inspection work orders or group projects will contain information gathered during the inspection including: Identification of the property location and owner contact information. A description of the stormwater system components. Identification of non-compliant structures and required corrective action(s). Digital photographs of non-compliant structures. Stormwater System Inspection Field Sheets The stormwater system inspection field sheets are documentation aids to assist the inspector in analyzing cleanliness and structural issues related to the long-term maintenance of stormwater management structures. The stormwater system inspection field sheet specifically identifies catch basins, Best Management Practice (BMP) structures, drainage pipes, swales/ditches, ponds, and exfiltration systems. The Field Inspection Sheet format and content may be altered at anytime to improve the inspection process. Inspection Feedback Should the stormwater system fail to meet the city approved performance measures, the city will mail a certified written Letter of Correction to the property owner of record detailing the non-compliance issues discovered during the inspection and the required methods of correction. A copy can be mailed to the rental tenant if requested. Typical corrective actions include: Using a vactor truck to clean trash, debris, and sediment out of filter boxes, catch basins, drainage pipes, hydrodynamic separators, and infiltration systems; Removing trash, debris, and overgrown vegetation within wet/dry retention ponds, outlet control structures, and ditch/swale systems; Using excavating equipment to remove sediment from ditches and wet ponds; and Using landscaping equipment to maintain retention pond and ditch/swale embankments. The corrective action must commence within thirty (30) calendar days of receipt of the written notification (i.e. the date of delivery of the certified letter). The date of delivery can easily be obtained from the United States Postal Service (USPS) by entering the unique identification number from the certified mail receipt online at Public Works Department staff will perform a follow-up stormwater system inspection after the thirty-day time period has passed. If no corrective action has been taken at that 6

9 time, the city reserves the right to enter into enforcement and penalty proceedings. All required corrective action(s) must be completed within sixty (60) calendar days of the notification. The Public Works Department staff reserves the right to grant extensions under extraordinary circumstances, as some corrective actions may require more time to complete. Any situation that is considered an eminent threat to the health and safety of citizens or the environment warrants immediate resolution of the hazard and may result in the issuance of an instantaneous emergency cease and desist order. All required corrective action(s) associated with this health and safety situation must be completed within seven (7) calendar days of receipt of the written notification. If the property owner fails to take, or commence taking, corrective action to the satisfaction of the City within the allotted timeframe stated in this manual or Letter of Correction, the city may enter upon the property, take corrective action, and place a lien on the property for the abatement costs. A sample Letter of Correction can be found in Appendix B. Re-inspections At the end of the sixty (60) day time period, Public Works Department staff will perform a final re-inspection. As a courtesy, the property owner should notify the city when all corrective measures have been completed so a final re-inspection may occur prior to the sixty (60) calendar day deadline. If any outstanding deficiencies exist on the property, then a secondary certified Letter of Correction will be issued with the updated noncompliance issues. However, the date of completion associated with the initial findings of the inspection remains in effect unless an extension is granted. Once the re-inspection confirms the stormwater system is functioning adequately in accordance with engineering design standards, the city will distribute a stormwater system Compliance Letter to the individual property owner(s) and/or rental tenants if requested. 7

10 Appendix A: Stormwater System Inspection Field Sheets Pipe and Pond System Exfiltration System Best Management Practice (BMP) Structures 8

11 (INSERT PAGES FROM EXCEL FILE HERE)

12 Appendix B: Stormwater System Inspection Letters of Communication Letter of Correction Compliance Letter 15

13 City of Myrtle Beach Department of Public Works - Street and Drainage Division P.O. Drawer 2468 Myrtle Beach, SC <First Name, Last Name> <Address Line 1> <Myrtle Beach, SC Zip code> April 11, 2008 Dear Mr./Ms. <Last Name>: Stormwater discharges are generated by runoff from land and impervious areas such as paved streets, parking lots, and building rooftops during rainfall events, and often the runoff contains pollutants in quantities that could adversely affect water quality. Successfully managing stormwater is vital to our coastal region given that stormwater ultimately discharges either into local soils or our two most valuable water resources, the Atlantic Ocean and the Atlantic Intercoastal Waterway. Pollutants of any kind can adversely affect the safety and appearance of our attractive beachfront, or possibly contaminate natural aquatic habitats and our source for drinking water. To maintain our high water quality standards and prevent flooding, the City of Myrtle Beach Public Works Department staff routinely inspects private stormwater systems within commercial or multi-family developments to ensure these stormwater systems are operating properly. These inspections are required as a part of both the City of Myrtle Beach Stormwater Management Ordinance passed in 1985 ( and South Carolina Department of Health and Environmental Control (SCDHEC), under the auspice of the National Pollutant Discharge Elimination System (NPDES) program ( authorized by the Clean Water Act. SCDHEC obligates the City to report its findings of stormwater systems that are not in compliance, and requires that individual property owners take immediate corrective action(s) once a noncompliance notice has been issued. During a recent inspection of the stormwater system located at <Address Line 1> on <Date>, the City inspector noted that a deficiency exists in the operation and maintenance of the system at this site. This deficiency includes the need of the following corrective measures: As the owner of record, the City requires that you address this/these maintenance issue(s) and completely correct the problem over the next sixty (60) calendar days. The owner of

14 record must commence taking corrective action(s) within thirty (30) calendar days of receipt of this written notification (i.e. the date of delivery of the certified letter). The City inspector will, at a minimum, re-inspect the site after the thirty (30) and sixty (60) day time periods have expired to ensure remediation progress has been achieved. If the corrective action(s) is/are not taken in a timely manner, the Stormwater Management Ordinance requires City staff to enter upon the premises, perform corrective action(s) needed to bring the private stormwater system into compliance, and place a lien upon the property for the associated maintenance costs. Once corrective action(s) have been completed, please provide the Public Works Department with documentation affirming the corrective measures are in place. A City inspector will conduct a follow-up visit to the site to verify that the stormwater system is in compliance. The City of Myrtle Beach has made great strides over the last several years in controlling stormwater runoff. We certainly appreciate your efforts to maintain the stormwater system on your property to fulfill the Community s goal of reduced flooding and enhanced water quality. While the City cannot recommend contractors to perform the corrective action(s), the local phone book yellow pages have listings under plumbing for drain and sewer cleaning and excavating contractors for pond cleaning. If you have questions, please feel free to call <First Name, Last Name> at Sincerely, City of Myrtle Beach Public Works Department 17

15 <Last Name, First Name> <Address Line 1> <Myrtle Beach, SC Zip code> April 11, 2008 Dear Mr./Ms. <Last Name>: Stormwater discharges are generated by runoff from land and impervious areas such as paved streets, parking lots, and building rooftops during rainfall events, and often the runoff contains pollutants in quantities that could adversely affect water quality. Successfully managing stormwater is vital to our coastal region given that stormwater ultimately discharges either into local soils or our two most valuable water resources, the Atlantic Ocean and the Atlantic Intercoastal Waterway. Pollutants of any kind can adversely affect the safety and appearance of our attractive beachfront, or possibly contaminate natural aquatic habitats and our source for drinking water. To maintain our high water quality standards and prevent flooding, the City of Myrtle Beach Public Works Department staff routinely inspects private stormwater systems within commercial or multi-family developments to ensure these stormwater systems are operating properly. These inspections are required as a part of both the City of Myrtle Beach Stormwater Management Ordinance passed in 1985 ( and South Carolina Department of Health and Environmental Control (SCDHEC), under the auspice of the National Pollutant Discharge Elimination System (NPDES) program ( authorized by the Clean Water Act. SCDHEC obligates the City to report its findings of stormwater systems that are not in compliance, and requires that individual property owners take immediate corrective action(s) once a non-compliance notice has been issued. During a recent inspection of the stormwater system located at <Address Line 1> on <Date>, the City inspector noted that a no deficiencies exist in the maintenance of the system at this site and the system is considered to be compliant We certainly appreciate your efforts to maintain the stormwater system on your property to fulfill the Community s goal of reduced flooding and enhanced water quality and we strongly encourage you to implement a stormwater maintenance program that includes seasonal inspections. If you have questions, please feel free to call <First Name, Last Name> at Sincerely, City of Myrtle Beach Department of Public Works - Street and Drainage Division P.O. Drawer 2468 Myrtle Beach, SC City of Myrtle Beach Public Works Department 18