Maintaining My Structural BMP Newsletter

county of san diego watershed protection program

Maintaining My Structural BMP Newsletter





Trees contribute to the beauty of San Diego County, but also play a vital role in protecting the environment. Trees can provide shade, filter the air we breathe, reduce erosion, and help remove pollutants from stormwater. Tree wells are an example of an enhanced site design Best Management Practice (BMP) that can be used for development or redevelopment projects to reduce the amount of pollutants going to the watershed/MS4, while providing multiple other benefits for the user and environment.

From above, tree wells are able to intercept stormwater through their canopy. Tree species with a larger canopy tend to capture more stormwater. Then from the ground level, tree wells divert stormwater runoff to the soil immediately surrounding the tree. Generally, the areas around the Tree Well are sloped to allow water to naturally flow into the depressed planting area. The runoff that is collected in the tree well filters through the soil, removing pollutants. In this manner, tree wells reduce the volume of runoff entering the storm drain system and can prevent surface floods. Tree wells are often found adjacent to walkways, driveways, and parking areas to capture and treat stormwater flowing from these surfaces.

The design of tree wells also allows them to be utilized in urban settings to effectively treat stormwater where other landscape options are typically limited or absent. Proper species selection and tree well placement can minimize problems that tend to be caused by roots and regular tree growth.


Do you have a Tree Well on your property? Utilize these County resources to find out more about the benefits and maintenance of Tree Wells.

testSan Diego Sustainable Landscape Guidelines


If you think you may have a tree well on your property, but not sure where, please contact our program for verification.


For questions regarding BMPs or the BMP program,

Contact us at:

County of San Diego Structural BMP Program

(858) 495-5323

To report storm water pollution or irrigation runoff call us at (888) 846-0800 or email us at
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Find My District


Report Stormwater Pollution
Report observed pollution to the correct jurisdiction.

Citizen Access Portal
Research property information and permits. Apply for some permits online.

GIS Maps
Find property information including zoning designation with our web-based mapping tool. 


Watershed Protection Website

Project Clean Water logo

Project Clean Water efforts are focused on providing a centralized point of access to water quality information and resources for San Diego County Watersheds. Click HERE to visit Project Clean Water’s website.