Green Streets and Creek Rehabilitation to Transform a Dense Urban Neighborhood
The City of National City, a community just south of downtown San Diego, recently finished rehabilitating a 1,000 foot creek segment and retrofitting almost 100 acres of tributary area using green infrastructure. These improvements are in and around one of the most heavily used parks in the City. The project incorporates elements of Smart Growth design and Low Impact Development (LID) into a low to moderate income area of the City’s downtown urban area, providing education, beautification, better water quality, and environmental justice benefits for the community. In addition to creek restoration, the project includes bioretention, rainwater harvesting and reuse, and infiltration. An educational pedestrian pathway with storm water themed murals and design elements, augmented with curb extensions and other improvements to improve walkability, runs through the project area. These pedestrian improvements link dense urban residential areas and a recently revitalized commercial corridor with mass transit and a major City park, which also provides access to the main water body in the City, Paradise Creek. The project highlights and enhances the creek, which was previously seen by the community as a concrete channel intended only for conveying storm water. Due to the high pedestrian foot traffic to these downtown destinations, there is a significant educational opportunity to teach the community how urban runoff connects them to their creek as it flows through bioretention planters down the street, across the park, and into Paradise Creek. To measure the project's educational impact on the community, a pre- and post-project public survey was conducted, and the results of the survey will be discussed during the presentation. As an additional educational feature, runoff captured in a 30,000 gallon cistern has been installed to water the vegetation in the park. This project’s LID retrofits and creek rehabilitation are a key component of the City’s approach to complying with the San Diego Bay Water Quality Improvement Plan and to fulfilling their commitment to restore the areas along Paradise Creek into areas utilized for recreation and education. Recognizing that green infrastructure retrofits and creek rehabilitation projects are being considered in many areas across the state, and that the final constructed condition of such projects often differs from the initial concept design, each portion of the talk will identify key lessons learned from construction and post-construction operation and maintenance that can be applied to other similar projects. Lessons learned from construction and initial operation and maintenance of bioretention and infiltration best management practices (BMPs) and from the cistern will be discussed. Pros and cons of the very low water use (drought friendly) landscape design of the bioretention and infiltration areas, which relies mainly on rock cobble and uses minimal and in some cases no plants, will be presented. BMP design used to achieve other benefits besides water quality and water conservation, including aesthetic improvements, community art, and pedestrian safety, will also be discussed. Information on operations and maintenance experience with the cistern, including the impacts of dry weather flows, leaf litter from trees in the drainage area, and the amount of irrigation demand from the park will be provided. Results from pre- and post-project effectiveness monitoring for flow and chemical constituents will be presented to evaluate the impact of constructed LID features. Finally, I will present lessons learned from the construction phase of the creek rehabilitation, including the unique BMP challenges of working in a water body. Note that this project is funded in part by two State Water Resources Control Board Proposition 84 grants, and the project area is considered a disadvantaged community.
Brianna Martin is an Assistant Project Scientist with D-Max Engineering, Inc. in San Diego. She has a bachelor’s degree in environmental science from UC San Diego and is a Certified Professional in Storm Water Quality (CPSWQ) and a Qualified Industrial Stormwater Practitioner (QISP). Some of Brianna’s recent projects include MS4 outfall monitoring programs, Industrial General Permit compliance support, grant management and writing, BMP effectiveness monitoring, and providing Water Quality Improvement Plan support services for municipalities.
John Quenzer is a senior scientist with D-Max Engineering in San Diego. He has a bachelor’s degree in environmental chemistry from UC San Diego and a master’s in environmental engineering and science from Johns Hopkins University. Some of John’s recent projects include LID conceptual design for storm water retrofits, developing updated jurisdictional storm water management programs for cities in San Diego and Imperial counties, serving as group co-coordinator for the San Diego Bay watershed management group, and overseeing MS4 outfall monitoring programs. When not working, John enjoys spending time with his wife and son, hiking, and basketball.