Climate Impacts & Resilience
The City is projected to experience a range of impacts due to climate change. These impacts include an increase in the frequency and severity of heatwaves, changes in precipitation patterns, including more intense rainfall events and longer periods of drought, and an increase in the frequency and severity of wildfires. Vulnerable populations may be disproportionately impacted by local climate change due to uneven exposure to hazards, differing levels of sensitivity to those hazards, and disparate capacities to adapt based on socioeconomic status, age, health status, and access to resources.
Urban Heat Islands
As temperatures rise, heat waves are expected to become more intense and last longer, which can lead to a range of health impacts, including heat exhaustion, heat stroke and dehydration. Heatwaves can also exacerbate air pollution, leading to increased respiratory problems. These impacts are particularly severe on vulnerable populations such as the elderly, young children, and those with pre-existing health conditions, who may be more susceptible to heat-related illnesses such as heat exhaustion and heat stroke. In addition to increasing the City’s tree canopy cover, the CEAP includes the following strategies to address urban heat island effect: 1) Revise City ordinance to permit contractors to start work before 7 a.m. and/or after 7:00 p.m. on excessively hot days with the authorization of the Community Development Director; 2) Explore cool pavement and permeable pavement options for streets and parking lots.
Tree Canopy Cover
The community forest with its native oak trees is the City’s largest, most visible, and arguably most important natural resource. It unites the built environment of our communities with the natural world. As living infrastructure, the forest provides environmental, economic and social benefits and helps Thousand Oaks to be resilient in the face of climate change by providing shade to protect against heat impacts, reducing air pollution, and providing habitat. To reduce heat impacts the City plans to: 1) Expand its urban canopy with climate-appropriate trees; 2) Prioritize tree planting investments in neighborhoods with limited green space, canopy coverage, or elevated air pollution; 3) Encourage tree planting on private property; 4) Fill in street trees where gaps exist.
Other measures planned for increasing resilience: 1) Develop resilience hubs/cooling centers at City facilities to provide shelter, electricity, and essential resources during heat waves, power outages, and natural disasters; 2) Establish emergency transit protocols to assist vulnerable populations with evacuation as necessary; 3) Encourage businesses, residents, and property owners to install resilient clean backup power supply; 4) Provide appropriate regulations to allow for development of distributed energy resources in residentially-zoned areas and throughout City.
Precipitation Impacts and Drought
The City is likely to experience changes in precipitation patterns, including more intense rainfall events and longer periods of drought. High intensity rainfall events could inundate the City’s existing stormwater system and lead to local flooding. In addition, drought can affect the availability of water resources, leading to water scarcity and potentially impact local flora and fauna, vegetation and landscaping, and the City’s urban forest.
The strategies shown above can be employed to reduce runoff and the risk of flooding. On-site retention involves rain gardens, retention basins, and rain barrels. Green Streets incorporate vegetation, soil, and engineered systems to slow, filter, and cleanse stormwater runoff.
California is no stranger to drought; it is a recurring feature of our climate, but climate change is making droughts more frequent and more intense. The City relies almost exclusively on runoff from the Sierra Nevada mountain snowpack to provide its water. Warmer temperatures produce less snow, and melt it faster and earlier in the year. The California Department of Water Resources predicts that by the end of this century, during a normal (non-drought) year, the Sierra Nevada snowpack will experience a 48-65% loss relative to the historical April 1 average.
Water Conservation
Water Resources Summary
Model Water Efficient Landscape Ordinance (MWELO) is a set of minimum landscape design and installation standards. It sets water use limits and incorporates specific requirements for soil, plants, irrigation, and stormwater. It is required for new landscaping over 500 SF or landscape renovation projects over 2,500 SF.
Through outreach, education, and rebates, property owners are encouraged to plant native and climate-appropriate plants and to employ water-efficient irrigation systems. The State’s MWELO sets standards for landscape design and irrigation for new construction and some renovation projects. It encourages the use of materials and plants that provide shade and retain moisture in the soil to reduce heat island effects. MWELO is an excellent tool but primarily affects new properties. Under the CEAP, the City will develop its local landscape ordinance to apply to all landscape projects regardless of size with sustainability design in mind.
Water resources and re-use are complex and multifaceted topics and require significant levels of effort and coordination. The City is making key investments in new infrastructure to help improve local water resiliency, hardening reservoir sites from potential power shut-offs or fire impacts to ensure that water is available for firefighting operations as well as boosting flow where needed. The City is also making several connections between its own system and neighboring water systems, which will enable us to have backup sources of water in the event of emergencies.
Metropolitan Water District (MWD) has made significant investments in storage by building the Diamond Valley Reservoir and building local supplies. Local agencies can be part of the solution. The City’s water ordinance has measures to reduce water runoff, eliminate non-functional turf, and encourage plants that are appropriate for our region.
CEAP measures to address water-related challenges include: 1) Pursue regional water supply solutions with neighboring water purveyors; 2) Pursue local groundwater options; 3) Pursue avenues to divert and treat storm water and treated wastewater for potable re-use; 4) Install a clean resilient power supply at City water pumps; 5) Reduce storm water runoff; 6) Address flood susceptibility in identified areas; 7) Identify and pursue adaptations to local stormwater system to address more intense precipitation events; 8) Reduce demand for irrigation through transitioning community to climate-appropriate landscaping; 9) Consider implementation of parcel-based water budgets based on State’s assessment of landscaped areas.
Wildfire Probability
An increase in the frequency and severity of wildfires is projected to occur over the coming decades. The City is already prone to wildfires with a risk higher than 88% of communities in the U.S., and climate change is expected to make the problem worse by creating hotter, drier conditions that increase the risk of ignition and make fires harder to control. Wildfires can damage or destroy homes and infrastructure, threaten human health, and harm local ecosystems. Populations with limited financial resources, higher rates of being uninsured, and without access to a vehicle to evacuate are particularly vulnerable to the impacts. In addition, these populations may have higher rates of physical or mental disabilities or respiratory conditions and inadequate access to healthcare.
Measures to address these concerns include: 1) Explore program to assist residents with fire hardening of homes; 2) Develop landscape ordinance that restricts trees known to spread wildfire embers.