City of Lake Oswego Stormwater Management Plan - FINAL-Public Comment

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• Publié par: Methong
• Nombre de lectures: 36
• Langue: English

Extrait

City of Lake Oswego Stormwater Management Plan (2008)   1.0   STORMWATER MANAGEMENT PLAN ORGANIZATION   The City of Lake Oswego’s 2008 Stormwater Management Plan (“SWMP”) is organized according to the federal requirements 40 CFR 122.26(d)(2)(iv)(A through D) and the City’s MS4 NPDES Permit (#101348) requirements listed in Schedule D(2)(c).     This SWMP is organized into the five major components listed below. The first four components match the four major components of the stormwater management plan that are outlined in the MS4 NPDES permit requirements Schedule D(2)(c) i through iv). Best management practices (BMPs) associated with each component are listed and described. To simplify the SWMP, BMPs to address all of the public education requirements under the first four components of the plan have been grouped into a fifth component.   Component #1: Structural and Source Control BMPs to Reduce Pollutants from Commercial and Residential Areas Component #2: A Program to Detect and Remove Illicit Discharges and Improper Disposal into the Storm Sewer System Component #3: A Program to Monitor and Control Pollutants from Industrial Facilities Component #4: A Program to Reduce Pollutants in Stormwater Discharges from Construction Sites Component #5: Public Education, Training, Coordination, and Public Involvement BMPs   Each of the five SWMP component sections begins with the applicable permit requirements and contains a description of applicable BMPs. At the end of each section, a table (BMP fact sheet) specifies the measurable goals associated with the BMP(s) and tracking measures for each measurable goal that the City will report on for the MS4 annual reports.   Each BMP has an assigned prefix, number, and name that help in identifying the activity and associated responsible party. Table 1 summarizes the BMP number prefix and associated BMP category and indicates the relevant SWMP component.   Table 1 BMP Name and Category Designations   BMP Number Prefix Associated BMP category Associated SWMP Component OM Operations and Component #1 Maintenance DEV Planning and Development Component #1 PEST Landscape Practices and Component #1 Pest Management

 

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BMP Number Prefix

ILL IND EC PE    

 

Associated BMP category

Illicit Discharge Detection and Elimination Industrial Inspections and Monitoring Construction and Erosion Control Public Education and Training

Associated SWMP Component Component #2

Component #3

Component #4

Component #5

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2.0 COMPONENT #1 – STRUCTURAL AND SOURCE CONTROL BMPS TO REDUCE POLLUTANTS FROM COMMERCIAL AND RESIDENTIAL AREAS   The City of Lake Oswego conducts a variety of activities focused on the prevention and removal of typical stormwater pollutants (sediment, hydrocarbons, trash and debris, nutrients, metals) from the MS4 system. Such activities include the inspection, maintenance, and repair of stormwater conveyance system components; the maintenance and repair of City streets; and the maintenance of public parks and recreational areas with the intent of minimizing fertilizer and pesticide use.   Activities or BMPs that pertain to the permit requirements listed under this component are provided below, along with reference to the applicable permit requirement. A BMP to address the permit requirement under Schedule B(2)(c)(i)(5) –A program to monitor pollutants in runoff from operating or closed municipal landfills or other treatment, storage, or disposal facility for municipal wasteis not provided, as the City does not operate any municipal landfills or other treatment storage and disposal facilities. A BMP associated with the education component of the permit requirement under Schedule B(2)(c)(i)(6)- A program to reduce to the maximum extent practicable, pollutants in discharges from municipal separate storm sewers associated with the application of pesticides, herbicides and fertilizer that will include, as appropriate, controls such as educational activities, permits, certifications and other measures for commercial applicators and distributors, and controls for application in public right-of-ways and at municipal facilities, is provided under Component #5 (Section 6).   2.1   BMP OM1 – Inspection and Maintenance of Publicly Owned Conveyance System Components   Permit Requirement Schedule B(2)(c)(i)(1) - Maintenance activities and a maintenance schedule for structural controls to reduce pollutants (including floatables) in discharges from municipal separate storm sewers.   The City of Lake Oswego will inspect publicly owned conveyance system components (specifically culverts, ditches, and inlets) on a complaint driven basis during the permit term. Components of the public conveyance system include culverts, conveyance ditches, inlet structures, and catch basins without sumps. Problem areas are identified during the continual inspections, and maintenance and/or repair/ replacement activities are scheduled promptly thereafter.   Inspections of public conveyance system components (specifically drainage pipe) also occur in conjunction with citizen complaints and inquiries. During inspections, problem areas are identified and maintenance and/or repair activities are scheduled and promptly conducted as necessary.   A database tracking system is updated during each maintenance cycle to allow the City to track and inventory their conveyance system.

 

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  2.2 BMP OM2 – Inspection and Maintenance of Publicly Owned Catch Basins with Sumps   Permit Requirement Schedule B(2)(c)(i)(1) - Maintenance activities and a maintenance schedule for structural controls to reduce pollutants (including floatables) in discharges from municipal separate storm sewers.   The City of Lake Oswego operates approximately 800 publicly owned, sumped catch basins. Sumped catch basins are classified by the City of Lake Oswego as those catch basins with a 12” deep or greater sump.  The City inspects all of their publicly owned,  sumped catch basins annually. Problem areas are identified during the annual inspection, and maintenance, repair, or replacement activities are scheduled thereafter.   90% of all sumped catch basins are cleaned at least once during the permit term. Maintenance activities primarily occur during the dry weather season. In general, cleaning of publically owned sumped catch basins involves removing standing water and debris from catch basin and sump. Debris level in catch basin is qualitatively noted on data collection forms along with other observations and background information (site location, date cleaned, etc).   As with the stormwater conveyance system maintenance, inspections of public sumped catch basins also occur in conjunction with citizen complaints and inquiries. As a result of public complaint or inquiry, problem areas are identified and maintenance and/or repair activities are scheduled as necessary.   A database tracking system is updated during each maintenance cycle to allow the City to track maintenance efforts and inventory existing sumped catch basins.   2.3 BMP OM3 – Inspection and Maintenance of Water Quality Treatment Facilities   Permit Requirement Schedule B(2)(c)(i)(1) - Maintenance activities and a maintenance schedule for structural controls to reduce pollutants (including floatables) in discharges from municipal separate storm sewers.   The City of Lake Oswego owns and operates public, structural water quality facilities. Such structural facilities currently include detention and sedimentation ponds, swales, pollution control manholes, and filter vaults that provide for pollutant removal by controlling flow, promoting infiltration, providing for sedimentation, and filtering pollutants from stormwater. All structural water quality facilities are inspected annually and routine maintenance is conducted annually.   Typical routine maintenance activities include mowing, trimming, inlet/outlet maintenance, and removal of debris. Watering water quality treatment facilities is conducted until new vegetation is established. Based on the results of the inspections, non-routine maintenance activities may be warranted. Non-routine maintenance activities include planting vegetation, reshaping/reconstructing,

 

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and silt and sediment removal. Proprietary system maintenance typically falls under non- routine maintenance activities.   The City of Lake Oswego is also beginning to implement a program to track private, structural water quality facility maintenance. The City has compiled an inventory of all known private structural water quality facilities, and during the permit term will follow up with property owners to ensure that a copy of the facility’s operations and maintenance agreement (required during development plan review) is on file with the City and conduct inspections of private water quality facilities. Private facilities typically are owned and operated by homeowner associations or similar private entities in Lake Oswego. As a result, most do not realize that they are legally responsible for the operation and maintenance of these privately owned facilities. The City of Lake Oswego will research permanent funding mechanisms to cover items such as private structural BMP owner education and outreach, operation and maintenance (O&M) plan review, and implementation of the private facilities O&M plans.   2.4 BMP OM4 – Street Sweeping of CurbedArterial and Residential Streets   Permit Requirement Schedule B(2)(c)(i)(3) - Practices for operating and maintaining public streets, roads and highways and procedures for reducing the impact on receiving waters of discharges from municipal storm sewer systems, including pollutants discharged as a result of deicing activities .   The City of Lake Oswego continues to conduct street sweeping activities throughout the City. Street sweeping is conducted on all major and minor curbed arterial streets and all curbed residential streets. Curbed arterial streets are swept a minimum of 17 times per year, and all curbed residential streets in the City are swept a minimum of four times per year.   A vacuum sweeper is used to minimize wash water from entering the stormwater conveyance system.   2.5 BMP OM5 – Deicing Activities   Permit Requirement Schedule B(2)(c)(i)(3) - Practices for operating and maintaining public streets, roads and highways and procedures for reducing the impact on receiving waters of discharges from municipal storm sewer systems, including pollutants discharged as a result of deicing activities .   The City of Lake Oswego applies washed gravel to roadways when ice is present. Street sweepers sweep up the applied gravel after the ice has melted and as promptly as resources and weather allows.   2.6 BMP OM6 – Road Maintenance and Repair Activities   Permit Requirement Schedule B(2)(c)(i)(3) - Practices for operating and maintaining public streets, roads and highways and procedures for reducing the impact on receiving

 

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waters of discharges from municipal storm sewer systems, including pollutants discharged as a result of deicing activities .   The City of Lake Oswego conducts road maintenance and repair activities continuously to prevent erosion and future pollution from occurring. Repair work is generally scheduled during the dry season when possible, to minimize polluted discharges from entering the stormwater conveyance system.   City conducted road maintenance and repair activities that would trigger erosion control requirements (an erosion and sediment control plan and/or permit) require that the project is monitored for erosion control compliance by City Staff.   2.7    BMP DEV1 – Master Planning for Stormwater Quality Improvement   Permit Requirement Schedule B(2)(c)(i)(2) - Planning procedures including a comprehensive master plan to develop, implement and enforce controls to reduce the discharge of pollutants from municipal separate storm sewers that receive discharges from areas of new development and significant redevelopment. Such a plan must address controls to reduce pollutants in discharges from municipal separate storm sewers after construction is completed. Controls to reduce pollutants in discharges from municipal separate storm sewers containing construction site runoff are addressed in paragraph Schedule D(2)(c)(iv).   Permit Requirement Schedule B(2)(c)(i)(4) - Procedures to assure that flood management projects assess the impacts on the water quality of receiving water bodies and that existing structural flood control devices have been evaluated to determine if retrofitting the device to provide additional pollutant removal from storm water is feasible. The City of Lake Oswego operates under a number of planning and development related documents with goals to reduce and/ or eliminate pollutant discharge to surface water bodies. The City’sComprehensive Planwas acknowledged by the Land Conservation and Development Commission in 1984 and is currently being reviewed and updated (as of July 2008), and it is anticipated that the review will take at least a year to complete. The review ensures the plan addresses current state land use planning regulations. Specific sections of theComprehensive Planaddress water quality and the state land use goals (Goal 5, Goal 6 and Goal 11). The City’sPublic Facilities Planwas originally adopted in 1990 as part of the Comprehensive Plan update and updated in 1997, and it provided an inventory and conditions analysis for the major elements of the City’s infrastructure including stormwater management facilities. Specific to stormwater master planning, the City is finalizing theLake Oswego Clean Streams Plan Thefinal in the fall of 2008., which is expected to be  Clean Streams Plan serves as an update to the previous surface water management master plan (dated 1992). TheLake Oswego Clean Streams Planserves as the basis for the stormwater management and facility infrastructure portion of thePublic Facilities Plandescribed above. The Lake Oswego Clean Streams Plan contains a number of recommended capital improvement projects (CIPs) for flow control and water quality that the City will

 

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reference for future utility and infrastructure improvement, as an update to their original 10-year CIP Plan. The City of Lake Oswego promotes LID technologies where practicable; many areas of the City of Lake Oswego contain soils that don’t support effective infiltration.     Prioritization of CIPs is generally based on overall planning goals, cost, public safety, and environmental impact. As funding is available, the City implements the CIPs and continues to update the CIP inventory.   Lake Oswego Code (LOC) 38.24.505 creates the Surface Water Management Utility which plans, designs, constructs, maintains, administers, and operates public surface water facilities including those projects identified within the City’s prioritized CIP list. Utility user charges are also established in the LOC, which fund portions of CIPs.   Generally, there is limited opportunity for retrofit of existing flood control facilities, as there are very limited facilities that solely address flood control. Most public drainage facilities are constructed for both flood control and water quality. The City of Lake Oswego operates one major flood control facility, and works with the Lake Oswego Corporation (Lake Corp.), who operates the gates, weirs, and overflow facilities related to operation of Oswego Lake. Water quality is always taken into account if the City is repairing, retrofitting or constructing new infrastructure, through compliance with their development standards and erosion and sediment control practices.   2.8    BMP DEV2 – Development Review   Permit Requirement Schedule B(2)(c)(i)(2) - Planning procedures including a comprehensive master plan to develop, implement and enforce controls to reduce the discharge of pollutants from municipal separate storm sewers that receive discharges from areas of new development and significant redevelopment. Such a plan must address controls to reduce pollutants in discharges from municipal separate storm sewers after construction is completed. Controls to reduce pollutants in discharges from municipal separate storm sewers containing construction site runoff are addressed in paragraph Schedule D(2)(c)(iv).   The City of Lake Oswego Planning, Engineering, and Building divisions of the Community Development Department share review responsibilities for new development applications. Specifically the Planning and Engineering Divisions review development proposals for consistency with the applicableComprehensive Plan policies, zoning, and City codes, including compliance with natural resource protection standards for wetlands, stream corridors, floodplains, etc. The Engineering Division specifically evaluates development proposals with regards to proposed stormwater conveyance, treatment, and disposal. Such development standards specific for stormwater conveyance, treatment, and disposal are specified in LOC Chapter 50.   Through the development review process, the City requires stormwater quality facilities for new development based on phosphorus removal efficiencies set forth in OAR 340-04- 0345 (and as modified by DEQ). The Engineering Division reviews new development applications for the appropriate structural controls to address the phosphorus removal in

 

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accordance with the City’s development standards. The City has aSurface Water Technical Guidance Handbookprovides design guidance and criteria for(2003) that stormwater quality facilities. Typical approved stormwater treatment facilities include bioswales, extended dry detention ponds, StormFilters, retention ponds, vegetated filter strips, and pollutant control manholes. The City plans to update theSurface Water Technical Guidance Handbookduring the permit term.   Redevelopment applications that are subject to the same requirements and development review process.   2.9   BMP PEST1 – Reduce Pollutants in Discharges Associated with the Application of Pesticides, Herbicides, and Fertilizers   Permit Requirement Schedule B(2)(c)(i)(6) - A program to reduce to the maximum extent practicable, pollutants in discharges from municipal separate storm sewers associated with the application of pesticides, herbicides and fertilizer that will include, as appropriate, controls such as educational activities, permits, certifications and other measures for commercial applicators and distributors, and controls for application in public right-of-ways and at municipal facilities.   The City of Lake Oswego has adopted the standard operating procedures (SOPs) for pest and landscape management activities, which utilize components of the City’s Integrated Pest Management (IPM) Program and defines appropriate application procedures and protocols along roadways, within City parks, and around water quality facilities for staff to adhere to during maintenance activities. Per the SOPs, the following activities are typical: •   Application of chemicals is reduced and/ or eliminated where possible; •   Regular removal of invasive plant species is conducted; •   Native plants are used for revegetation projects; and •   Only spot spraying is conducted for blackberry removal.

  In addition, any work that is conducted within public right-of-ways requires certified, licensed applicators.   Specific education measures and staff training are discussed under Section 6.0 - Component #5 - Public Education BMPs.     2.10 BMP PEST2 – Update the City of LakeOswego Integrated Pest Management Plan (IPM).   Permit Requirement Schedule B(2)(c)(i)(6) - A program to reduce to the maximum extent practicable, pollutants in discharges from municipal separate storm sewers associated with the application of pesticides, herbicides and fertilizer that will include, as

 

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appropriate, controls such as educational activities, permits, certifications and other measures for commercial applicators and distributors, and controls for application in public right-of-ways and at municipal facilities.   The City of Lake Oswego conducts pest management activities (see PEST1) in accordance with SOPs that utilize components of the City’s IPM Program. The City has had an IPM program in place for close to thirty years, but the overall Program needs to be revised and made current. The City has set a measureable goal of revising the current IPM to reflect the current state of practice related to IPM and review current practices for areas of improvement, modification and improved efficiency.   The City currently conducts a variety of sustainable and environmentally friendly practices that are not currently reflected in the City’s IPM Program. For example, the Maintenance division has long concentrated on buying disease resistant plants and plants that attract beneficial insects so they stay healthy without insecticides. Turf maintenance began experimenting with low phosphorus fertilizer twenty years ago by working with manufacturers to mix a special Lake Oswego blend. Water management was improved by installing a computerized irrigation system. For many years wetting agents have been used as standard practice at the golf course and park turf areas to increase water absorption. Every year all the shrub beds are mulched with a compost/dark bark mix to help organically feed the soil, smother weeds and retain soil moisture. Medians are filled with plants, which reduces weed growth since healthy plants shade out and out-compete weeds. This technique also works for a lawn since healthy vigorous turf can out-compete weeds and thus no chemicals need to be used.

 

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BMP Fact Sheet: Component #1 – Structural and Source Control BMPs   Introduction: The purpose of this BMP category is to improve water quality by implementing appropriate operations and maintenance practices.

Measurable goals and tracking  BMP OM1-Inspection and Maintenance of Publicly Owned Conveyance System Components  measures: o Measurable the publicly owned stormwater conveyance system components (culverts, ditches, and inlets) Inspect Goal: when there is a citizen complaint or inquiry. o Tracking of conveyance system components inspected and/or repaired annually. Measure: Number o Measurable Inspect Goal: the publicly owned conveyance system (pipes and other referenced components) when there is a citizen complaint or inquiry. o Tracking Number Measure: of inspections and repair activities conducted annually as a result of citizen complaints.   o Measurable Goal: Based on the results of the inspections and citizen complaints, maintain the conveyance system components in need of service during the permit term. o Measure: Describe all maintenance activities potentially impacting water quality that are conducted Tracking annually.

 

  BMP OM2-Inspection and Maintenance of Publicly Owned Catch basins with Sumps   o Inspect all of the publicly owned, sumped catch basins in the City annually. Measurable Goal: o and % of total catch basins inspected annually. Measure: Number Tracking oover the permit term, based on regular a minimum of 90% of City owned sumped catch basins  Maintain Goal: Measurable maintenance schedules and results of inspections. o Tracking Measure: Number and % of total catch basins maintained annually.   BMP OM3-Inspection and Maintenance of Water Quality Treatment Facilities   o inspect all of the publicly owned water quality treatment facilities. Measurable Annually Goal: o Measure: Tracking Number and % of total public water quality treatment facilities inspected annually. o conduct routine maintenance activities (as defined in Section 2.3) to ensure functionality of Goal: Annually Measurable public water quality treatment facilities. o Trackingof public water quality treatment facilities maintained annually and description of  Number Measure:

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BMP Fact Sheet: Component #1 – Structural and Source Control BMPs   maintenance activity. o Goal: Refine program for tracking private water quality treatment facility maintenance activities Measurable o inspect 10% of private water quality facilities for which an O and M agreement is on file with Measurable Goal: Annually the City. o Measure: Tracking and % of total private water quality treatment facilities inspected annually; Document Number the date of inspection.   BMP OM4 – Street Sweeping of Curbed Arterial and Residential Streets o Goal: Annually Measurable sweep curbed arterial streets a minimum of 17 times. o Tracking List Measure: all curbed arterial streets and dates swept. o Goal: Measurable sweep all curbed residential streets a minimum of 4 times. Annually o Tracking Measure: List all curbed residential streets and dates swept.   BMP OM5 – De-Icing Activities o Measurable Goal: Pick up all deicing materials as promptly as weather and resources allow.   BMP OM6 – Road Maintenance and Repair Activities There are no measurable goals identified for this BMP.   BMP PEST1 – Reduce Pollutants in Discharges Associated with the Application of Pesticides, Herbicides and Fertilizers. o Measurable Reduce Goal: the overall quantity of pesticides, herbicides, and fertilizers applied to City owned property. o Annually report on the quantity of pesticides, fertilizers, and herbicides applied to City Tracking Measure: property. BMP PEST2 – Revise City of Lake Oswego Integrated Pest Management Plan (IPM). o current City of Lake Oswego IPM by second annual report (fall 2010). Revise Goal: Measureable o Measure: Tracking Report on the status of IPM revisions annually. o Goal: Implement the revised City of Lake Oswego IPM once adopted. Measureable

 

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