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  You Are Here: Home: Government: Departments: Public Works: Stormwater



Report a Spill
Call 253-447-4320

After Hours & Weekends 253-841-5431 or 1-844-821-8911 (Toll Free)

This page includes information and links to resources about stormwater management in and around Bonney Lake.


Stormwater is rain and snow melt that runs off surfaces such as rooftops, paved streets, highways, and parking lots. As water runs off these surfaces, it can pick up pollution such as: oil, fertilizers, pesticides, soil, trash, and animal waste. From here, the water might flow directly into a local stream, bay, or lake. Or, it may go into a storm drain and continue through storm pipes until it is released untreated into a local waterway.

In addition, the large impervious surfaces in urban areas increase the quantity of peak flows of runoff, which in turn cause hydrologic impacts such as scoured streambeds channels, instream sedimentation and loss of habitat. Furthermore, because of the volume of runoff discharges, mass loads of pollutants in stormwater can be significant.

Source: Washington State Department of Ecology - 

What are stormwater ponds?

Stormwater Pond MapStormwater ponds are manmade features generally located near your neighborhood or business. They are designed to mimic the ecological function of naturally occurring ponds and wetlands. Water from these ponds drains to a lake, river, stream, wetland, or may infiltrate into the ground.

Depending on the age of the pond, it may serve one or two stormwater management functions. Older ponds were designed to slow the flow of stormwater and discharge it at a rate to minimize downstream flooding. Newer ponds are designed to manage water volume as well, but also provide a water quality benefit. A properly designed stormwater pond will remove a substantial amount of sediment and other pollutants from stormwater before releasing this water downstream. Some ponds are planted with wetland plants and are known as stormwater treatment wetlands.

What should a pond look like?

Next to being properly designed to store and convey stormwater, landscaping is the most critical component in the proper functioning of the stormwater pond. Historically, many ponds were designed to have mowed grass edges as a form of “sales appeal” for the developer, rather than being landscaped for the long term benefit of the pond. Mowed grass to the water’s edge on all shorelines means the pond is not providing its full ecological value. Unmowed vegetative buffers are essential to long term health of ponds and waterways.

Buffers should also extend into the pond where possible using emergent wetland plants. The most important factor when designing a buffer is to choose the proper vegetation for the slope and soils. The buffer should include a diverse plant community that provides both habitat and aesthetic appeal. The proper buffer will provide both a water quality and wildlife component:

  • Water Quality: The proper plant community will prevent shoreline soil erosion (bank slumping) around the pond. It will also prevent herbicides and pesticides from going directly into the pond. Eliminating the need for fertilizers and frequent mowing will reduce the potential for algae blooms.
  • Wildlife: A diverse plant community will provide habitat for a variety of wildlife, including predatory insects, amphibians and birds which keep mosquito populations in check. Tall native grasses will also discourage Canada Geese from taking over the pond and adjacent lawns.
  • Fences: Ponds are generally designed with gentle slopes so if someone falls into the pond, they are able to climb out. In locations where walls or steeper slopes are incorporated into the pond, a safety fence may be added. Many ponds have fences installed to help identify the presence of the facility and indicate in a passive way that they are not swimming or play areas. However, since ponds are intended to be natural areas, like streams or natural ponds, the City avoids use of fences where possible.

How are ponds maintained?

Much pond maintenance, such as sediment and aquatic plant removal requires the equipment and expertise of a professional. Some work, like weed control or planting of approved plants can be performed by volunteers. Native plant buffers around the pond and its discharge waterway require maintenance to prevent non-native invasive species from taking over. This is critical because the native plants often require more time to become well established than the weedy species. Debris removal and weeding will be required as small plants develop. Plant identification is very important for this operation since it is difficult in the beginning to distinguish between the non-native and native plants. Invasive plant removal will be an annual task but will diminish as the native plants fill in.

Who maintains Bonney Lake’s ponds?

Public stormwater ponds are maintained by City crews. The Stormwater Utility has two fulltime employees responsible for maintaining nearly 120 acres of stormwater ponds. This is in addition to 40 miles of stormwater mains, 2,007 catch basins, 78 miles of swales and ditches and many other pieces of stormwater infrastructure. During the summer months, 6 to 7 temporary employees are hired by the City to assist the full time Stormwater Utility employees.

Regulatory required maintenance is focused primarily on water quality benefits and ensuring that ponds have adequate sediment storage and inlets and outlets are not blocked by plants or debris. At times, these maintenance activities may detract from pond aesthetics, but efforts are made to reduce any such negative impact. Private ponds are maintained by private landowners and inspected by City staff.

Stormwater crews are limited by budget constraints, so resources are focused primarily on functional pond attributes like storage, access, and water quality, and less on pond aesthetics. The stormwater pond map and mowing schedule shown here are provided to give an approximate timeframe for when you can expect maintenance activities to be completed at the pond located near you. Pond visibility and acreage are two criteria used in establishing the schedule order. The schedule is always a best case scenario as issues such as weather and wildlife activity can play a significant role in maintaining the order of the schedule. Also, before regular spring/summer pond maintenance begins, the right of way and common areas throughout the City are maintained. Once that is complete, then pond maintenance can begin in earnest. Depending on the effort required with the right of way maintenance, pond maintenance can be delayed.

How can I help?

The biggest impact homeowners and businesses can have is to prevent pollutants from entering these ponds. Ponds are designed to remove pollutants, but they are not able to remove all pollutants.

In particular, soaps used to wash cars cannot be removed by ponds and actually suspend other pollutants to reduce the effectiveness of ponds. Don't wash your car in a place that drains into a pond. Using natural yard care practices and limiting the use of chemicals around the home are good measures everyone can take to reduce the source of pollutants, rather than relying on imperfect pond facilities to remove those pollutants.




Stormwater Pollution Prevention & Water Conservation Calendar

Each year the City of Bonney Lake develops a calendar to promote pollution prevention and water conservation practices. To help convey this message, the City holds an art contest open to students grades K-12 attending qualifying schools or home schooled in Bonney Lake! Each month in the calendar displays artwork from area students related to water conservation, recycling, and stormwater pollution prevention.

Stormwater Calendar 
A limited number of free calendars are printed each year - call (253) 862-8602 to see if calendars are still available! 

City of Bonney Lake Stormwater Management Program

The Bonney Lake Municipal Code (BLMC) includes two sections that address the City's Stormwater Management Plan:

We want your feedback regarding the development, implementation, and update of the Stormwater Management Program. Please send comments to the Assistant Engineer.

Stormwater Management Program:

Reports and Other Resources

NPDES Phase II Annual Reports:

Other Stormwater Resources:

Stormwater Education Resources:

Video: "Water Undone: The Efforts to Save the Puyallup River Watershed"

View online at

The Puyallup River watershed is a major source of fresh water into Puget Sound through Commencement Bay in Tacoma. But it suffers from a multitude of pollution problems, including land use policies, as detailed in this documentary from UW Tacoma.

The program takes viewers through the interwoven watershed-river system that supplies water for drinking, irrigation, recreation, food, wildlife and the natural beauty of the Northwest. It explains the effects of urbanization on Salmon runs and the the Puget Sound, and includes information on Lake Tapps and its role in providing a regional water supply source.

Video: "Stormwatch: Municipal Stormwater Pollution Prevention"

This 20-minute video provides information on stormwater pollution prevention and offers advice and training for good housekeeping, spill response, materials storage and handling, landscape maintenance and street maintenance, and how to spot potential "illicit discharges" occurring around town.

Where Does The Water Go?

Pierce County's "Where Does the Water Go?" interactive map shows you how water flows in Pierce County. It was designed to promote awareness about stormwater runoff and how pollutants can impact Puget Sound and our natural waterways. 



Stormwater Inventory

  Structures Facilities
Catch Basins / Inlets Manholes Pipe (Miles) Ponds Dry Wells
2017 2,007 373 40 mi 56 78


1,923 371 39 mi 54 77


1,923 371 39 mi 54 77


1,646 315 33 mi 46 71


1,098 180 19 mi 31 55


754 108 13 mi 14 54


702 108 12.4 mi 10 46


383 69 8 mi 6 30



19306 Bonney Lake Blvd
Bonney Lake, WA 98391
Mailing Address
City of Bonney Lake
Attn: Public Works - Stormwater
19306 Bonney Lake Blvd
Bonney Lake, WA 98391-0944

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