Is there a list available of project areas currently under consideration for green streets?

Thus far the priority catchments have been identified, and within these areas, project sites are currently being evaluated. Both the priority catchments and the projects themselves will be provided in the Green Streets Clean Water Plan.

The Watershed Protection Program sponsored project information can also be found at, for projects already moving forward: www.sandiegocounty.gov/stormwater and click on the Green Infrastructure icon.


The Mapleview Green Street Project was described during the Green Streets Clean Water Webinar. Is it one of the 30 projects that will be included in the Green Streets Clean Water Plan?

No, the Mapleview Green Street Project is currently in design and is anticipated to go to construction later this year. Thirty (30) additional projects will be identified in the Green Streets Clean Water Plan.


Are the priority projects available to the public?

Candidate projects have not yet been selected, as they will be developed in consideration of the information we receive from stakeholders during the meeting and from the survey. The candidate project locations will be included in the draft and final Green Streets Clean Water Plan, expected by early 2022.


How can we nominate specific areas for a project?

The survey includes an open response field for additional questions or comments. Please provide suggestions for candidate sites there.


Will all medians be raised and landscaped?

The incorporation of raised medians on County Road projects depends on a number of factors such as road classification, traffic movement and traffic safety. In most cases raised medians are not vegetated. The use of raised medians with vegetation will be considered on green street projects only if there are opportunities to direct runoff to these areas where the most water quality benefits can be achieved.  Specific project design will be presented to the community similar to any Capital Improvement Program project.


Will trees survive after they receive all those pollutants?

Trees improve water quality by slowing rain as it falls to the Earth, and helping it soak into the soil. By filtering the water with tree roots and soil, pollutants get trapped and diluted which reduces the impact of water pollution.


How will vegetation be irrigated?

Irrigation requirements would depend on the type of vegetation proposed and availability of water. If irrigation is needed, it will be installed consistent with the County’s Water-Efficient Landscape Design Manual. Specific project design will be presented to the community similar to any Capital Improvement Program project.


Will traffic calming mean reduced lanes?  What if the community doesn’t like reduced lanes?

Traffic calming can be accomplished through a number of different measures without resorting to the reduction of traffic lanes. Any of the proposed traffic calming measures will be communicated to the community and presented to the local Community Planning Group.


Are Type IV (protected) bike lanes under consideration for the Mapleview project or any of these other projects?

Type IV bike lanes are not included as part of the Mapleview Project. Fitting Type IV bike lanes into existing roadways can be challenging due to the limited space within the existing built environment and right of way. If a green street project is proposed in an area identified for Type IV bike lanes in the County’s Active Transportation Plan, the bike lane opportunity will be considered along with other priorities for that specific project. 


Will tree wells be designed so that the trees will not buckle pavement as they mature? Great potential for urban forestry here.

The County’s Green Streets Standard Drawings, which will be used for this project, include design features and specifications for the tree wells and biofiltration media that direct roots downward rather than horizontally, providing sufficient volume for root establishment and runoff storage. These design features are intended to avoid impacts to sidewalks and roadways while allowing trees to reach their natural heights.   


Could this program create a vector control problem by allowing standing or ponded water and thus breeding of mosquitos?

Projects will be designed to avoid the ponding of water. The County’s Green Streets Standard Drawings, which will be used for this project, intentionally limits the depth of ponded water and require efficient drain times to avoid becoming a breeding environment. Projects with underdrains will provide a backup mechanism for collected runoff to exit the treatment systems to ensure that ponding will not occur.


How are these projects funded?

Most Green Infrastructure (GI) projects in the County roadway have different funding than the regular Capital Improvement Program projects. GI projects are primarily funded through the County general fund and supplemented with water quality grants, whereas typical CIP projects are funded through highway user tax (gas tax), and Federal Highway grants.


What jobs will this program create? Are they long-term or from construction only?

There will be construction jobs during the construction stage, but also long-term jobs can be created by the effect of improving the community with more aesthetically pleasing features, for example, if you have more people visiting your community that will create more jobs, not to mention the jobs in maintaining the vegetation and other features.


Who will maintain the landscaping?

Depending on the nature of landscaping there could be more than one entity involved in conducting the actual maintenance. The County Department of Public Works (DPW) is responsible for ensuring that the landscaping in the right-of-way is maintained either through the use of the County Road Crews or through the use of a landscape contractor.


Where will the funding come from to maintain the landscaping?

County general fund is currently identified as the funding source for green street projects. The goal is to limit cost of maintaining landscaping through the use of drought tolerant, native, and non-invasive species. Once the vegetation is established, there is a potential for irrigation and maintenance costs to be reduced. Funding will be from a variety of sources, including general fund.


How will water supply concerns be considered for vegetated green streets that will require irrigation?

Vegetated green streets projects will be landscaped using drought-tolerant, non-invasive vegetation, with a preference for native species. Such plants will require some supplemental water when first established with the goal of transitioning away from irrigation over the long-term. Additionally, green streets projects are intentionally sited and designed to receive runoff from roads, curbs/gutters, and sidewalks during both dry weather (from sources such as over-irrigation), and wet weather (as stormwater), further offsetting the irrigation demand.


How will green streets projects impact residential street right-of-way frontages that a homeowner may have landscaped themselves?

While the majority of projects will be located outside of residential areas, the County recognizes that residents are invested in the condition of the right of way adjacent to their property and understand that some right-of-way areas have been landscaped. If a project is planned in such a location, the County will take this into consideration during the design phase. In cases where prior landscaping necessitates removal, the replacement would be designed to be aesthetically pleasing, pollinator friendly, etc.


Is proximity to schools being considered in the placement of green streets projects?

Proximity to schools is one of many factors considered in the overall scoring of the projects.

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