Urban areas face increasing pressure from stormwater runoff, polluted waterways, and limited open space. Integrating wetlands into Green Infrastructure (GI) systems helps cities capture runoff, filter contaminants, and restore ecological functions. These systems improve water resilience while creating accessible recreational landscapes for nearby communities. Explore how the Urban Orchard Project in South Gate demonstrates these principles in practice against international benchmarks.
Urban Wetland Green Infrastructure Systems
Urban GI systems integrate natural processes into engineered urban landscapes to manage stormwater and improve water quality. Urban wetlands form a central component within these systems because they store runoff, filter pollutants, and slow water movement. GI networks often combine wetlands with permeable surfaces, vegetated channels, and infiltration areas. This distributed approach reduces pressure on conventional drainage infrastructure. It also improves watershed health while creating functional public spaces.
Stormwater Capture and Pollutant Filtration Mechanisms
Urban wetlands function as biological filtration systems that treat stormwater before it reaches rivers or coastal waters. Runoff from streets, roofs, and parking areas often contains oils, heavy metals, pesticides, and sediment. Wetland soils and vegetation capture these pollutants through sedimentation, microbial processes, and plant uptake. Water then infiltrates into underlying soils or moves slowly through vegetated channels. This process improves downstream water quality and reduces pollutant loads entering impaired waterways.
Distributed Storage and Groundwater Recharge
GI systems increase urban water resilience by capturing stormwater close to where it falls. Wetlands and permeable landscapes temporarily store runoff during rainfall events. Stored water gradually infiltrates into soils, which supports groundwater recharge in suitable geological settings. This distributed storage reduces peak flows in drainage channels and lowers flood risk. Municipal water systems also benefit when recharged aquifers supplement long term supply reliability.
Community Space within Water Management Infrastructure
Urban wetland GI projects often combine water management with recreational and social infrastructure. Designers incorporate walking paths, open lawns, and habitat features within stormwater landscapes. These multifunctional spaces transform underused or degraded sites into public parks. Communities gain access to green space while cities improve environmental performance. This integration helps align infrastructure investment with public health, climate adaptation, and neighborhood revitalization goals.
Case Study: Urban Orchard Project, South Gate, California
The Urban Orchard Project in South Gate demonstrates how stormwater infrastructure can support water quality improvement, groundwater recharge, and community revitalization. The project occupies a former industrial site located between a concrete section of the Los Angeles River and Interstate 710. It converts the underused parcel into a 30 acre multi use park that integrates wetlands, bioswales, and permeable landscapes.
The system diverts stormwater and urban runoff from the Bandini Channel into constructed wetlands and vegetated infiltration areas. These features capture and store millions of gallons of runoff each year. Wetland vegetation and soils filter contaminants such as oils, pesticides, heavy metals, and urban debris. This treatment process reduces pollutant flows entering the Los Angeles River, which appears on the state list of impaired or threatened waters.
The initiative operates under California’s stormwater management framework and received partial financing through the State Water Resources Control Board Stormwater Grant Program. The project secured an $8 million dollar grant funded through Proposition 1 water bond allocations. Proposition 1 authorized $7.5 billion dollars in statewide funding for water infrastructure, ecosystem restoration, watershed protection, and drinking water improvements. The State Water Resources Control Board administers these funds and supports local project implementation.
Design features also support groundwater recharge and public recreation. Permeable surfaces and infiltration areas allow captured stormwater to percolate into local aquifers. At the same time, the park provides open space, recreational facilities, and ecological habitat within a dense urban community of about 100,000 residents. By linking water quality improvement with public amenities, the project demonstrates how stormwater infrastructure can deliver environmental and social benefits.
Take-Out
Urban wetlands integrated within GI systems enable cities to capture runoff, improve water quality, recharge groundwater, and create multifunctional public landscapes that strengthen long term water resilience.