Street Sweeping Program
Current Program
The current street sweeping program in the City of Sammamish is designed to maintain the integrity of its stormwater infrastructure, reduce urban flooding, and improve water quality as part of its obligations under the NPDES Phase II Municipal Stormwater Permit. The program includes regular inspection and maintenance activities detailed in the City's annually updated Stormwater Management Program Plan.
View the Current Street Sweeping Schedule here.
Critical Aspects of the Street Sweeping Program
The program emphasizes not just the operational aspects of street sweeping but also its broader environmental impact, particularly regarding water quality benefits and compliance with regulatory requirements. This holistic approach aims to optimize streesweeping's benefits while effectively managing its costs and operational challenges.
Area Prioritization
The City focuses on arterials due to their higher traffic volumes, which contribute to higher pollutant levels. Arterials are swept more frequently than neighborhood streets, considered a lower priority, and swept less often due to lower traffic volumes and various physical obstructions like parked cars and vegetation.
Program Implementation
Street sweeping is performed on approximately 60 miles of arterial roadways and 220 miles of local access roads. The frequency of sweeping varies seasonally, with more frequent sweeping in fall and winter to manage leaf fall and other debris.
Equipment and Disposal
The program uses rear brooms and air vacuum sweepers. The collected material is transported to a designated yard before final disposal at a landfill. No testing is conducted on the street, which is swept before disposal.
Pollutant Loading and Tracking
A significant part of the program's monitoring involves estimating the removal of pollutants like phosphorus and nitrogen using specific calculative tools. However, direct measurements of debris or pollutant loads are not typically taken.
Evaluation and Adaptive Management
The program's effectiveness is periodically evaluated, with adjustments made based on operational performance and community and environmental monitoring feedback.
Cost
The street sweeping operations are contracted out. Costs for arterial and neighborhood street sweeping and emergency spill response are budgeted in the Stormwater Operations and Maintenance fund.