Bellevue s Approach to Stormwater Management

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1 Bellevue s Approach to Stormwater Management By Don McQuilliams Operations Manager-Regulatory Compliance and Surface Water Bellevue Utilities Department City of Bellevue, Washington Bellevue, Washington is situated between Lake Washington and Lake Sammamish and is the fifth largest City in Washington State with a residential population of 140,000. Bellevue is the high tech and retail center of the Eastside and home to more than 130,000 jobs. Bellevue envisions itself City of Bellevue skyline as a City in a Park with a vast network of trails and nearly 100 parks throughout the City. Bellevue operates under an elected City Council/Mayor with an appointed City Manager that runs the day to day operations of the City. Bellevue covers 33 square miles and has a cultural diversity with 50% of the population being of minority race or ethnicity. Bellevue s Storm and Surface Water Utility was formed in 1974 and was one of the first fully operational Storm and Surface Water Utilities in the nation. Founded from a need for flood control, Bellevue initially set up a Storm Drainage Utility Task Force to guide the operations of the Utility. Recognizing the importance of preserving Bellevue s streams and lakes, the task force stated that The Utility should act to improve water quality as well as to control flooding and property damage. The task force would later become the Environmental Services Commission that is still in operation today as an advisory group to the City Council and the Utilities Department. The Storm and Surface Water Utility drafted its first drainage master plan in 1976 which recommended combining on site Storm water controls with regional flood control facilities. In 1988, a comprehensive drainage plan was crafted that identified a new rate structure and an increased focus on system capacity as well as a focus on preserving aquatic and riparian habitats to encourage the preservation of fish runs. In 1993 the Storm and Surface Water Utility combined with the Water and Wastewater Utilities to become the Bellevue Utilities Department as it exists today. An update to the comprehensive plan in 1996 updated policies and identified numerous capital projects around the city to improve drainage and further the focus on prevention of stream degradation. The most recent update to the comprehensive plan occurred in 2015 and was relabeled as the Storm and Surface Water System Plan.

2 Bellevue s Storm and Surface Water system itself is a combination of public and private ownership of pipes and streams. The public system is comprised of 411 miles of underground pipe with installation dates going back to the 1950 s. As a concentrated effort to gain better knowledge of an aging infrastructure, Bellevue recently initiated a condition assessment project to CCTV 100 miles of the piped system. Prior to this only 2% of the system was being video inspected annually with most of that work focusing on staying ahead of transportation overlay projects to minimize the need to open roadways up after new pavement is installed. Over 20,000 catch basins and 2,300 manholes are within the public system and are inspected as part of the City s Phase II NPDES permit requirements. To date, the Utility has been required to inspect all the CB s and manholes once every permit term or once every 5 years. As of August 1 st, 2017, the City is required to inspect all the CB s every other year which more than doubles the efforts necessary to complete this task. Challenges faced by the Utility are similar to those seen by other municipalities of similar size; aging infrastructure, retrofitting in an urban environment and integration of low impact development (LID) are on the forefront. Under current Storm and Surface Water code, LID is required as the first approach to storm water control but poses problems in Bellevue as much of our landscape does not infiltrate well or is on steep slopes. Recently Bellevue prepared an infeasibility map to assist development review and developers by illustrating where LID is not recommended within the City. The Storm and Surface Water system s natural components contain more than 81 miles of streams and three small lakes under a mixture of public and private ownership. Bellevue works closely with our neighbors that have streams running through their properties to ensure a mutual understanding of the importance of Bellevue s streams. Within the stream system, Bellevue Utilities owns 136 acres of land that contain 10 instream regional detention facilities (RDF s). The regional detention facilities came to be in the 1980 s and consist of flood gates placed in series throughout several of the streams to regulate flows by detaining large amounts of water in each regional detention pond and releasing it at a controlled rate to minimize downstream erosion and flooding. Kelsey Regional detention facility before and after a storm event The gates at each regional facility are adjustable either onsite or remotely through our telemetry system and are monitored 24/7 through a SCADA system that also collects historical pond level data. Using the level data in combination with rain gauge data, this provides the Utility a means to actively monitor the system during rain events and to review the effects of a storm after an event has passed. The operation and maintenance of the public drainage system is performed by in-house staff in the Storm and Surface Water Section. The crew consists of 16 full time employees and several seasonal staff to help during the summer when inspection and cleaning is at its peak production. The section is organized into five program areas; Inspection, Cleaning, Repair, Condition Assessment and Special Projects. Much of the work conducted by Storm and Surface Water staff is under the regulatory requirements of the NPDES permit and Washington Department of Fish and Wildlife (WDFW) requirements.

3 The Inspection Program is responsible for the physical examination of the structures within the system with the Cleaning Program following behind the inspection staff. Our Repair Program is driven by deficiencies found through inspection efforts and those found during condition assessment of the pipelines. The program focuses on point or spot repairs that can be performed usually within a day or two while larger rehabilitation and replacement work is assigned to the Engineering Division and released via public work contracts. The Condition Assessment program conducts the CCTV work of the system as well as interior inspection of pipes for roots, potential structural defects and blockages. Recent efforts to complete CCTV work on 100 miles of pipe within the system are keeping this program quite busy. Vactor crews maintaining a vault The Special Projects group is responsible for the inspection of all in stream work where excavation of material is periodically necessary at culverts, pipes ends and sedimentation facilities. The stream system is inspected annually to identify those areas that need attention and the work is coordinated using both in-house staff and contractors. Prior to any stream excavation work, we are required by WDFW to relocate all fish within the project site. To do this staff are trained in electroshocking and fish exclusion. Most of the streams in Bellevue contain an abundant population of small trout, sculpin, lamprey and occasional salmon. Staff are required to Electroshocking crews performing fish exclusion collect all fish and contain them temporarily in a clean holding tank where they are measured and identified before being released away from the project site. Staff take enormous pride in their fish exclusion methods and have great success in ensuring survivability during this work. Stream maintenance is a unique aspect of Bellevue s Storm and Surface Water operations and in addition to the special project work, staff monitors and maintains 35 parcels with known beaver populations across the City to minimize flooding from beaver dam activity. When beaver dams are found, they are monitored routinely and pond heights are established that allow Beaver populations to continue to utilize their ponds while not getting overzealous and flooding the neighbors. Staff come in as needed to remove portions of Beaver dams in six inch lifts so we do not impact downstream water quality. Our activities within the streams are permitted via a programmatic permit from the City s Land Use division and two General Hydraulic Approval through WDFW that allow for this work under defined work methods. Beaver taking a rare break from dam building Also housed in our Operations and Maintenance Division is the Water Quality and Regulatory Compliance Section that is responsible for spill response, illicit

4 discharge investigation, private drainage inspections, education and outreach and NPDES compliance reporting. The Storm water aspects of this group are conducted by three full time Senior Engineering Technicians (SET) and our Stream Team Coordinator. The three SET s spend much of their time working their way through the City conducting private drainage inspection of commercial facilities, apartment complexes and private plats with storm water controls. Inspections are scheduled partially as determined by NPDES permit requirements and partially based on historic need. Inspectors visit each site, inspect on site storm water facilities and provide detailed Staff cleaning up after an oil spill recommendations for cleaning or repairing the facilities as needed. Facility maintenance is completed by the private owners and reported back to the inspector who tracks the facility over time. In addition to their inspection, they use this time with the facility owners/operators to educate them on the benefits of storm water treatment and flow control as well as assisting them in methods to reduce overall pollution generated from a site. Education and Outreach is a requirement of the NPDES permit and an activity that reaches beyond permit requirements. Our Stream Team Coordinator spends much of her time reaching out to businesses, schools and streamside property owners to educate and inform them of the issues surrounding water quality and how they can help to minimize pollution to our waterways. The Water Quality and Regulatory Compliance Section also does the reporting associated with our NPDES permit and assists with environmental permitting Outreach materials necessary for the Storm and Surface Water Section to do their work. The Assessment Management program in Bellevue Utilities recently decided to conduct video review of 100 miles of Storm water pipeline over a four-year period. Much of Bellevue s system was constructed prior to any storm water requirements (pre-1974) and another good portion of the system was constructed with only peak flow control requirements for the time ( ). This left the Utility realizing that only 20% of the system had been verified from an asset management perspective. The initial focus of the CCTV work is around older Corrugated Metal Pipe (CMP) and concrete pipe. Bellevue Utilities has had a robust asset management program for both water and wastewater infrastructure for some time with storm water asset management efforts lagging the other two utilities. Along with asset management, the mapping team works to ensure that all the Utilities (Water, Wastewater and Storm water) infrastructure maps are kept up to date and asset data is accurate. The maps are used daily by field and office staff so accurate mapping is vital to making informed decisions. The mapping group also works with the City s IT Department to develop new way to conduct business via mobile mapping solutions and is working with us to leverage the tools GIS can bring to the table.

5 The City of Bellevue has a dedicated Capital Improvements Program split into five distinct programs. Flood Control, Fish Passage Improvements, Stream Channel Modifications, Infrastructure Rehabilitation and Minor System Improvements make up the program areas. Each program may produce individual projects or programs may be combined to leverage funding for larger more complex projects. Repair and rehabilitation work that is outside in-house capabilities is referred to the Engineering Section for their expertise to get a project out to bid and managed through construction. A new canister vault being installed The Watershed Planning group is integral in ensuring the health of Bellevue s streams. They develop and update basin plans to evaluate past and current conditions of the streams, plan and monitor salmon recovery efforts and perform field assessments. They also provide hydraulic modelling to assist with project planning and to guide the Utility on where future efforts should be focused. This group often represents the Storm and Surface Water Utility at regional discussions and staff are considered leaders in their respective fields of study. Moving forward Bellevue has developed five strategic initiatives as identified in the 2015 Storm and Surface Water System Plan. The Primary Storm Water Infrastructure initiative is designed to identify components of the storm water system that are vital to the performance of the system regardless of public or private ownership. The Property Management initiative is looking at all properties owned by the Utility and evaluating the best opportunities for future use; an initiative for Improving Water Quality is set up to look for areas where retrofits can be best applied; and our Open Stream Condition Assessment initiative is looking at the current and potential future conditions of our streams. Finally, the City Watershed Management initiative will be focused on identifying which drainage basins we should be focusing our attention. By focusing Stormwater management efforts on more than permit requirements, Bellevue continues to be a leader in the region on Stormwater management and promotes A surface water system that controls damages from storms, protects surface water quality, supports fish and wildlife habitat, and protects the environment. (Bellevue Storm & Surface Water mission statement as defined in the 2015 Storm and Surface Water System Plan)