a landscaped rain garden

Water Conservation and Stormwater Mitigation: EcoBlock Designs and Strategies

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The Water team has been developing ways to implement water conservation and stormwater management strategies for the Oakland EcoBlock.  Here are some ideas we are currently exploring: 

Urban greening 

Urban greening is the practice of making urban spaces green! This tactic replaces unnecessary pavement within landscaping strips between the curb and sidewalk with street trees and native planting. Besides providing aesthetic and health-related benefits, vegetation can cool the block via evaporation and shade pavement surfaces that absorb and radiate heat (also known as the “urban heat island effect”). 

Some ways to green-ify the EcoBlock include: 

Planting monument trees 

The team is exploring the idea of planting “monument” trees near the block. Not only would these trees help cool and improve the quality of the air, but they could be a beautiful way to highlight the uniqueness of the EcoBlock without drawing unwanted attention. 

Managing & treating stormwater 

The team is brainstorming different ways for stormwater management and treatment. One approach is to modify existing landscaping strips by allowing street runoff to flow through them and filter urban pollutants like hydrocarbons and heavy metals via the vegetation and soil (also known as “biofiltration”). Not only would this strategy improve overall water quality, but it would also slow down and reduce the amount of stormwater that enters nearby creeks and streams. 

We are considering two options for stormwater treatment along the street: 

  1. Have stormwater flow through swales 
    Stormwater could enter and flow through existing planting strips through curb cuts. This would preserve the existing curbline but depress the landscaping such that stormwater can flow—by gravity—from the street into the planted area. The soil inside the planter strips would be improved so the planting area could act as a “sponge” that absorbs, treats, and evaporates stormwater. 
  2. Incorporate bulb-outs 
    Bulb-outs can increase the existing landscape strips’ potential to manage stormwater. Adjusting the curb line to extend, or “bulb-out,” several feet into the existing street pavement would create better functioning stormwater treatment areas by “reclaiming” some of the paved area for landscaping. While the curb line would need to be modified, no parking spots would be eliminated: the parking aisle would simply shift towards the center of the street in places where stormwater bulb-outs are located. This allows for more comprehensive soil amendment and larger planted areas for stormwater to filter through and evaporate. 
landscaped bulb-out area in the rain
Stormwater filtering through a landscaped bulb-out. Credit: Craig Boman

Building an EcoBlock parklet 

The team identified a unique opportunity to create a shared, outdoor community “parklet” at the end of the block. A parklet is a small, public open space or seating area that typically replaces parking or under-utilized paved areas within a public right-of-way; it can include either permanent or temporary/ movable elements—the latter allowing for a flexible space that can be easily reprogrammed based on community needs. 

The parklet could incorporate:

  • Stormwater treatment
  • A community garden space where people in the neighborhood can cultivate fruits and vegetables
  • An outdoor working and eating area with tables, benches, and other seating; electrical outlets could be built in to allow for activities like playing music at block gatherings 
  • Murals or other displays of community art 

Harvesting rainwater 

Not only can roof rainwater capture offset potable supplies and help with stormwater management, but it is typically quite clean and requires little or no treatment before use. Irrigation use—which doesn’t require treatment—is common. Indoor rainwater use, including that for drinking, is less common but water of drinking quality can be achieved with treatment packages. 

Roofs cover about 1/4 of the total block; other impermeable surfaces cover another 1/4 or more. During heavy rains, much of the water falling on these impermeable surfaces flows quickly to storm drains and/or the street. This can overwhelm storm drains, flood streets, and result in excessive stream flows—even causing floods. Carefully designed rainwater harvesting systems can lower the maximum and total amount of roof-associated flows and in some systems, divert them to places where water can percolate into the soil and replenish groundwater. 

Implementing at-home water interventions

Ensuring efficient water use is another key goal. We plan to install water-efficient appliances (e.g. dishwashers, clothes washers & dryers, showerheads, toilets, bathroom & kitchen faucets) that meet, and often exceed, current industry standards. One metric is the WaterSense label, which follows the U.S. Environmental Protection Agency (EPA)’s criteria for water-efficient performance and specifications and certifies products that save at least 20 percent more water than market competitors. Another certification is from the California Energy Commission (CEC), whose regulations ensure consumer products comply with energy and water conservation requirements at both the state and federal levels. The East Bay Municipal Utility District (EBMUD) also provides eligible customers with educational resources and rebates on interventions like native, drought-tolerant planting, flowmeter installation, and greywater reuse. 

The Water team is excited to be part of an ongoing effort to create more resilient, flexible, and sustainable communities. We look forward to working with residents to implement water-conserving strategies for a greener EcoBlock!

Cover image credit: Craig Boman

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