19.2: Green Infrastructure and Climate Action Planning

Water is one of the most essential elements of life. Green infrastructure and climate action planning, if done well, can help ensure a secure and reliable flow of water to meet the needs of cities and agriculture, among other thirsty entities. The stakes are high. Researchers from the Center for Environmental Systems Research (University of Kassel, Germany) and the Nature Conservancy (Washington, DC) did a comparative study that examined climate change and urban growth globally. They found that rising levels of competition for water are pitting the needs of cities against the needs of agriculture. The study projects that urban water demand will increase 80% by 2050 in 482 of the world’s largest cities. Over the same period, the deficit in available urban surface water is expected to increase.

The water-climate-energy nexus

In the case of California, nearly 10% of the state’s GHG emissions come from the energy-intensive water system. Pumping, treating, and heating water consumes approximately 20% of statewide electricity use—and 30% of business and home use of natural gas. The San Diego region is actively seeking ways to supply water more efficiently, capture storm water using climate-smart tactics, and foster integrated regional watershed management. Green infrastructure is one of the favored approaches.

California’s 2018 Fourth Climate Change Assessment Report published data projecting that an increase in the number of extreme weather events will likely bring more torrential downpours and flooding to many parts of California and nearby Mexico. Green infrastructure includes rain gardens, bioswales, permeable pavement, rainwater harvesting, and other naturally designed features created to conserve or enhance land, wetlands, and ecosystems. Green infrastructure that reduces flooding while making more efficient use of water saves money and energy in ways that reduce a city’s carbon footprint and vulnerability.

Green infrastructure can play a significant role in climate change mitigation and adaptation while enabling ecosystem regeneration. Green infrastructure incorporates ecosystem functions into human settlements and working lands. Serious efforts are now being made to incorporate green infrastructure into municipal climate action plans. Green infrastructure programs and policies in the US have mainly focused on improving water systems. But that is changing.

Figure 19.2.1 Green infrastructure builds resiliency. Reproduced from the EPA.

The US Environmental Protection Agency has expanded the definition to describe an array of products, technologies, and practices that use natural systems, and/or engineered systems that mimic natural processes, to enhance environmental quality and provide utility services. Figure 19.2.1 shows elements of green infrastructure that builds urban resilience. Green infrastructure defined in this way may include urban and rural networks of green spaces and other natural elements such as rivers, lakes, forests, and canyonlands that connect villages, towns, cities, and working lands.

The concept can be stretched a bit further to include community composting facilities, green roofs and green walls, and green streets and alleyways, among numerous other clever ways to couple human and natural systems in the provisioning of utilities and public services. Designed well, green infrastructure can use a combination of vegetation, soils, and natural processes to manage water and create climate-friendlier, healthier urban environments. These systems can range from micro to more macro scales—from household rain gardens and green roofs up to large tracts of undeveloped natural lands.

Green infrastructure can help cities adapt to storm events and flooding, as well as drought, through climate-smart design that integrates human-built infrastructure (engineered systems for handling storm water) with natural environmental features (for example, watershed hydrology, ecosystems services). This can be accomplished in ways that join concerns about climate change, equity, justice, and health where people live.

Water quality, supply, and infrastructure improvement

In November 2014, California voters approved Proposition 1 (Prop 1), The Water Quality, Supply, and Infrastructure Improvement Act of 2014. Prop 1 authorized $7.5 billion in general obligation bonds for water projects including surface and groundwater storage, ecosystem and watershed protection and restoration, and drinking water protection. Prop 1 included $510 million in funding to improve integrated regional water management (IRWM) throughout the state. The Prop 1 IRWM Grant Program is administered by the State of California’s Department of Water Resources, which is funding projects that help meet the longterm water needs of the state.

Integrated regional water management (IRWM)

The Prop 1 IRWM Grant Program provides support for “disadvantaged community involvement” in the grant process. The State of California defines disadvantaged communities (DACs) as those areas throughout California that are most negatively affected by a combination of economic, health, and environmental burdens. These burdens include poverty, high unemployment, and health conditions like asthma and heart disease, as well as air and water pollution and hazardous wastes.

The state’s Office of Environmental Health Hazard Assessment developed the California Communities Environmental Health Screening Tool (“CalEnviroScreen”) to identify DACs in California, in part to help target DAC-eligible localities where a certain percentage of the state’s cap-and-trade funding is required by law to be awarded (directly benefiting the people inhabiting that particular place). The law specifies that 25% of the revenue available from cap-and-trade sources must be used within communities designated as disadvantaged—the justification being that these communities are likely to be more vulnerable and thus especially hard hit by climate change.

In 2018, the State of California Department of Water Resources awarded a $1.17 million Prop 1 IRWM grant to UC San Diego, as part of a regional cluster of Prop 1 IRWM grants compiled and facilitated by the San Diego County Water Authority. San Diego’s 2019 IRWM strategic plan includes efforts to address climate change through more effective water resource management, including ways to enhance the resiliency of local water resources while reducing greenhouse gas emissions. UC San Diego IRWM researchers teamed up with the San Diego Housing Commission—a major grant partner. This 2018 collaborative grant is titled Disadvantaged Community Planning Project (DAC): Alternative Non-Potable Water Supplies, Xeriscape Design and Flood Prevention for DACs. The DAC grant is a good example of localization involving water systems and green infrastructure that can help bend the curve.

The DAC project has an integrated design approach that includes a strong public health component, a research translation process for community residents, and water-conserving methods that include xeriscape design, flood control, water use management, and urban agriculture. UC San Diego and the San Diego Housing Commission joined forces with the Scripps Institution of Oceanography, Public Health Alliance of Southern California, San Diego Food System Alliance, and Global Action Research Center (Global ARC). Together this group is designing a half dozen shovel-ready projects for which funding will be sought once the design phase is completed.

The DAC project addresses core challenges for bringing water resource resilience to California’s DACs, which are faced with water scarcity, urban heat island effects, a lack of access to healthy food, rising potable water prices, and periodic flooding from intense storms. Alternative nonpotable water reuse systems (for example, laundry-to-landscape graywater use, rainwater harvesting) can strengthen urban resilience by supporting urban agriculture. The project’s plans for drought- and flood-resilient green spaces are also good for environmental public health. One of the more difficult aspects of work like this is the need to translate current research, science, and policy around alternative nonpotable water reuse into designs that can be permitted, effectively managed, and useful to residents in DACs and publicly supported housing. In order to maximize potential benefits, significant effort has to go into joining bottom-up grassroots efforts that reach into the resident base of communities with “treetop” efforts within the government and other institutions. One treetop effort that has the potential to join local and global objectives, by embracing green infrastructure, is climate action planning. Municipalities, counties, port districts, and other subnational as well as national agencies are creating and implementing climate action plans.

C40 and climate action plans

C40 is a network of the world’s megacities. It has rapidly grown since its birth in 2005. C40 facilitates collaboration among 94 of the world’s largest cities with the intent to accelerate meaningful and measurable climate change solutions. C40 represents 700+ million citizens and one-quarter of the global economy. The mayors of C40 cities are committed to delivering on the most ambitious goals of the Paris Agreement at the local level. As outlined in Box 19.2.1, C40 defines a climate action plan as a strategic document (or series of plans and documents) that demonstrates how a city will deliver on its commitment to address climate change.

The C40 mayors have joined forces with 9,000 others committed to taking action called for in the Paris Agreement. The C40 mayors estimate that the combined collective impact of these commitments could achieve annual reductions from “business as usual” of 1.4 gigatons of CO₂ equivalent (CO₂e) in 2030 and 2.8 gigatons CO₂e in 2050.

Box 19.2.1  Climate Action Plan Objectives and Strategies

A climate action plan will:

• Develop a pathway to deliver an emissions neutral city by 2050 at the latest and set an ambitious interim target and/or carbon budget.
• Demonstrate how the city will adapt and improve its resilience to the climate hazards that may impact the city now and in future climate change scenarios.
• Detail the wider social, environmental, and economic benefits expected from implementing the plan, and improve the equitable distribution of these benefits to the city’s population.
• Outline the city’s governance, powers, and the partners who need to be engaged in order to accelerate the delivery of the city’s mitigation targets and resilience goals.

A city will do this by:

• Considering adaptation and mitigation in an integrated way, identifying interdependencies to maximize efficiencies and minimize investment risk.
• Setting an evidence-based, inclusive, and deliverable plan for achieving transformational mitigation and adaptation, centered on an understanding of the city’s powers and wider context.
• Establishing a transparent process to monitor delivery, communicate progress, and update climate action planning in line with governance and reporting systems.

C40 Cities Climate Planning Framework. 2018. Chapter 1, page 4. Retrieved from https://resourcecentre.c40.org/clima...framework-home.

Unfortunately, while real progress is being made, many cities have not yet been able to address climate change. Several deficits and obstacles stand in the way. Relevant city policies and action plans are not yet in place; urban and environmental planning regulations are out of step with the complexities posed by climate change; misinformation and a lack of public awareness make communication about climate change risks and vulnerabilities difficult.

Green infrastructure at a watershed scale

Figure 19.2.2 OVGG Community Garden and Chollas Creek in the Pueblo watershed, San Diego, CA. Adapted from Google Earth; inset photograph by Keith Pezzoli.

Connecting climate action planning with strategies to green a bioregion’s infrastructure is a good way to advance climate change mitigation and adaptation. An example of this can be seen in a vacant land asset mapping project that took place in San Diego, California. Figure 19.2.2 shows the Pueblo watershed (the polygon area layered as blue) in San Diego County. The dark blue line depicts one of the most polluted creeks in the United States, Chollas Creek. Chollas Creek drains into San Diego Bay, one of the most polluted bays in the US. Contamination of Chollas Creek and the San Diego Bay are in part due to the way urban development paves over the earth. Streets, parking lots, buildings cover the land with impervious surfaces, reducing the porosity necessary for rainwater to seep into the earth. Consequently, rain events pick up surface pollution that gets dumped directly into the bioregion’s creeks, bays, and ocean.

Figure 19.2.3 Bioswale at the Ocean View Growing Grounds, San Diego, CA. Photograph by Keith Pezzoli.

During storm events, flooding is a major problem, a problem likely to get worse in Southern California with climate change. Thus, significant effort is going into figuring out how to reclaim the Earth’s capacity to absorb storm water. This is where green infrastructure comes into play. The tiny yellow polygons shown in Figure 19.2.2 are 810 vacant lots distributed throughout Southeast San Diego. UC San Diego’s Bioregional Center did a survey of these vacant lots as part of a research grant. Many of the 810 vacant lots would be very good sites for urban agriculture and installations of green infrastructure. The inset photo in Figure 19.2.2 shows a work group planting a food forest on what was one of the 810 vacant lots. The site now includes a community garden and food forest; it is called the Ocean View Growing Grounds (OVGG). Over the period from 2014 to 2019, local residents, community leaders, civically engaged academics, various professionals, students, and volunteers transformed the vacant lot. Members of OVGG installed a bioswale on-site to retain water for the food forest. The bioswale in this case is a simple carvedout depression in the land, spanning 30 by 20 feet and surrounded by the planted trees, shrubs, and plants (Figure 19.2.3). A bioswale is a hydromodification of a landscape to slow, collect, infiltrate, and filter storm water.

Part of the OVGG narrative speaks to how a plot of contaminated vacant land (what the EPA designated as a brownfield site because of concerns about toxicants in the soil, discussed below) got transformed into a neighborhood garden resource as well as a watershed asset. The neighborhood garden part is easy to understand; the site now produces fresh fruits and vegetables in a food desert (that is, a geographical area that suffers from a deficit of markets providing healthy food). The watershed part of the story is less obvious but merits attention for ecological reasons. OVGG sits within the Pueblo watershed with a great deal of impervious services (streets, parking lots, driveways, alleyways). Paving over the land with concrete has created an urban runoff problem that ends up degrading Chollas Creek. Chollas Creek drains the Pueblo watershed, which empties into the heavily contaminated San Diego Bay.

The bioswale at OVGG is a hydromodification of the land surface that improves on-site water retention and flow. This also provides a benefit to the health of the Pueblo watershed. It does so by reclaiming some of the watershed’s capacity to be more spongelike as opposed to impermeably hardscaped. At least 100 of the 810 vacant lots surveyed in the Chollas Creek watershed appear to be well positioned with respect to their location in the watershed’s urban runoff flow paths. If a concerted effort were made to hydromodify some of the vacant lots, as was done at the OVGG site, then, it is reasonable to assume, less pollution would end up in the waterways. Herein lies an opportunity to think about creating green infrastructure improvement districts.

Imagine incentivizing owners of vacant land to allow community groups to use their land for urban agriculture, at least for some defined period until said landowners decide to develop their land. Now imagine 20 or 30 landowners taking advantage of the incentive as part of a green infrastructure improvement district. As a result, 20 or 30 vacant lots get transformed by local groups of residents, school or faith-based organizations, neighborhood associations, and the like, into community gardens and/or food forests. The locals working on these lots could get support through the green infrastructure improvement district. For instance, there could be small grants to install low-cost but effective bioswales and/or rain gardens. Rain gardens are smaller-scaled versions of bioswales. Both bioswales and rain gardens are landscape elements designed to slow and filter storm water, and both are, in effect, small-scale natural climate solutions. This scenario is not farfetched. In 2018 the State of California passed the Urban Agriculture Incentive Zones Act (Assembly Bill 551). This bill allows landowners in metropolitan areas to receive tax incentives for putting land into agricultural use. Cities and counties must first create urban agriculture incentive zones to set the stage. With the intent to scale up efforts like this, UC San Diego’s Bioregional Center—supported in part by a grant (P42ES010337) from the National Institute of Environmental Health Sciences, Superfund Research Program—enlisted hundreds of students to do site suitability analysis of the 810 vacant lots in the Pueblo watershed shown in Figure 19.2.2. Site suitability analysis in this context refers to a method of assessment that gauges the qualities of the land and its surroundings as a potential growing space (for example, the lot’s soil condition, access to water, adjacent land uses, slope, shading, plant cover, trees, upkeep). This effort helps to embed small micro interventions (a community garden on one lot) in a larger watershed context.

The Bioregional Center contributed the image shown in Figure 19.2.3 to the sixteenth report of the Good Neighbor Environmental Board. Said report, which focused on ecological conservation in the USMexico border region, was submitted in 2014 to President Obama and the Congress of the United States. The image as included in the report has the caption “Vacant lot in San Diego being converted into a food forest and site for urban ecological restoration.” This line of thinking adds value to and helps justify/advance efforts like California’s Assembly Bill 551. But this effort, as good as it sounds, is not without its risks. Some of the vacant lots are contaminated with lead and other toxicants. Contaminated storm water and urban runoff might negatively affect the soil that people are using to grow food in the community garden and/ or food forest. The Community Engagement and Research Translation teams of UC San Diego’s Superfund Research Center are providing soil testing and risk assessment communication to deal with this concern.

Many obstacles, not just pollution, stand in the way of meeting the high demand in Southeast San Diego and other urban food deserts for places to grow fresh fruits and vegetables. Much work needs to be done to change legislation and regulations. Climate action plans are helpful insofar as they elevate systems thinking that values the greening of infrastructure and effort to work with nature not against it. Urban forestry is now included as an important part of the City of San Diego’s climate action plan. The City of San Diego and the City of Tijuana plan to use geographic information systems (GIS) as a way of locating the best sites for green infrastructure, including the use of vegetated bioswales for storm water management and the strategic use of trees, including food forests, for carbon sequestration and other benefits.

The Good Neighbor Environmental Board report mentioned above argues that a vigorous and engaged urban forestry program (a natural climate solution) is critical to meeting San Diego’s integrated commitments to ecological restoration, climate change, carbon sequestration, storm water reduction, and water conservation. With these goals in mind, the City of San Diego developed a long-range urban forest management plan to guide the city’s urban forest into the future.

Understanding natural climate solutions and urban-rural linkages is especially important in a transborder metropolis like San Diego–Tijuana.

Figure 19.2.4 San Diego–Tijuana US-Mexico border. Adapted from Google Earth.

The two cities share a watershed, so collaborative binational land management is crucial to any hope of realizing climate-friendly sustainable development. The San Diego–Tijuana shared bioregion located along the US-Mexico border has a south-to-north slope to the land. Storm water flows from Tijuana across the border into the US, picking up along the way tons of soil washed loose from Tijuana’s rapidly urbanizing canyons. The erosion is a major problem. Tijuana’s thinly vegetated steep canyon slopes are easily disturbed by poorly planned urbanization lacking adequate infrastructure. The eroded soil, trash, and contaminants that flow from Tijuana’s canyons into the US clog the wetland on the US side. This puts farmland at risk of contamination and causes frequent beach closures to protect public health. The soil loss and land degradation release carbon to the atmosphere.

Research universities, and local partners, on both sides of the US-Mexico border have formed an alliance to try to help solve some of the border region’s complex problems. A recent grant from the National Science Foundation (NSF, 2018 award number 1833482) provided support for several workshops in the US and Mexico geared to scoping out an actionable research agenda for a binational Border Solutions Alliance. One of the work groups for these workshops is named Measuring, Understanding and Improving Natural Climate Solutions: Enabling Carbon Neutral Development through Transborder Urban-Rural Linkages and a Green Infrastructure Nexus, clearly indicating its focus.