Climate change—natural change or change caused by human activities—can and will affect water, wastewater, and stormwater utility infrastructure today and well into the future. The tangible assets that make up water and wastewater utility infrastructure systems include large raw water storage facilities, stormwater collection systems, trans-basin diversion structures, potable and wastewater treatment plant equipment, transmission lines, local distribution systems, and finished water storage facilities. All are located in the natural and engineered environments affected by climate change.

There are two fundamental factors that water and wastewater utilities must consider when planning to address the implications of climate change:  the direct and indirect impacts of climate change on infrastructure, and adapting infrastructure planning, design, and asset management to handle these changes. The risks of not planning for the potential impacts and subsequent adaptation of infrastructure systems to climate change are increased vulnerability to physical failure, deteriorating physical condition, internal and external corrosion, mechanical stress failure, and the inability to handle changing system demands and loads.

Impacts of Climate Change

The exact impacts of climate change on utility infrastructure have the potential to be very complex and will likely be largely unknown until they actually occur. However, the drinking water and wastewater research communities have started thinking through myriad possible direct and indirect impacts of the effects of climate change on infrastructure systems.

Direct impacts result from the effects of climate change on drinking water and wastewater infrastructure system functions and operations. Direct impacts may be caused by changes in average daily temperatures, more frequent and intense rainfall events, rising sea levels, and sustained and extreme droughts. Average daily temperature changes can alter soil temperatures and the buried infrastructure environment, challenge treatment systems by affecting the quantity and quality of runoff into surface waters, and change water demand for irrigation and urban uses. More frequent and intense rainfall events can challenge treatment systems by increasing turbidity and sedimentation, or cause direct flood damage to above-ground utility facilities and buried infrastructure. Rising sea levels can lead to saline intrusion into groundwater aquifers, challenging treatment systems and increasing corrosion of buried infrastructure. Sustained drought can change the buried infrastructure soil environment and can also increase water demand for irrigation and urban uses.

Indirect impacts result from longer-term secondary effects of climate change on drinking water and wastewater infrastructure systems. For example, indirect impacts may result from the shifting of population centers that can lead to changes in waste loads, water use patterns, and the needs for storage and distribution system capacity. Indirect impacts can also result from gradual changes in socioeconomic systems that affect capital resources or result in revenue challenges for utilities.

Adapting to Climate Change

In order to address the impacts of climate change, water and wastewater utilities are adapting with a new way of thinking for planning, design, and working with asset management strategies. Utility rehabilitation, repair, or replacement decisions will need to account for climate change impacts. The water and wastewater industries will need to increase the resiliency of infrastructure by changing standards, specifications, and changing design criteria. New materials will be needed that can better withstand temperature fluctuations and drier or wetter conditions. The water and wastewater industries are also investigating decentralized systems as a way of managing climate change impacts. Decentralized systems provide distributed sites for water treatment and storage for potable water systems, and distributed sites for wastewater collection, treatment, and return for wastewater systems. These decentralized systems give utilities the ability to single out and manage individual zones of treatment or distribution during weather-related emergencies or in periods of demand or load changes.

Many water and wastewater utilities have begun to respond to climate change by understanding their system’s vulnerability and then entering into long-term planning that allows for adaptation to climate change. Tools and reports are available from the Water Research Foundation that can help utilities with this new way of thinking and planning.