Flood barriers to protect critical infrastructure include levees, dikes and seawalls. A related strategy is flood proofing, which involves elevating critical equipment or placing it within waterproof containers or foundation systems.

• See how Anacortes, Washington Rebuilds Water Treatment Plant for Climate Change
• See how Blue Plains Wastewater Facility in Washington DC Reinforces Facility Against Floods

Increasing the amount of groundwater storage available promotes recharge when surface water flows are in excess of demand, thus increasing climate resilience for seasonal or extended periods of drought, and taking advantage of seasonal variations in surface water runoff. Depending on whether natural or artificial aquifer recharge is employed, the required infrastructure may include percolation basins and injection wells.

Diversifying sources helps to reduce the risk that water supply will fall below water demand. Examples of diversified source water portfolios include using a varying mix of surface water and groundwater, employing desalination when the need arises and establishing water trading with other utilities in times of water shortages or service disruption.

• See how Tampa Bay Diversifies Water Sources to Reduce Climate Risk

Increased drought can reduce the safe yield of reservoirs. To reduce this risk, increases in available storage can be made. Methods for accomplishing this may include raising a dam, practicing aquifer storage and recovery, removing accumulated sediment in reservoirs or lowering water intake elevation.

• See how Fredericktown, Missouri Prepares for Climate Change Drought Risk

Rising sea levels, combined with reductions in freshwater runoff due to drought, will cause the salt water-freshwater boundary to move further upstream in tidal estuaries. Upstream shifts of this boundary can reduce the water quality of surface water resources. Installation of low-head dams across tidal estuaries can prevent this upstream movement.

Water utilities are one of the major consumers of electricity in the United States. With future electricity demand forecasted to grow, localized energy shortages may occur. The development of "off-grid" sources can be a good hedging strategy for electricity shortfalls. Moreover, redundant power supply can provide resiliency for situations in which natural disasters cause power outages. On-site sources can include solar, wind, inline microturbines and biogas (i.e., methane from wastewater treatment). New and back-up electrical equipment should be located above potential flood levels.

Relocating utility infrastructure, such as treatment plants and pump stations, to higher elevations would reduce risks from coastal flooding and exposure as a result of coastal erosion or wetland loss.

• See how Iowa City, Iowa Closes Vulnerable Wastewater Facility

Water utilities are one of the major consumers of electricity in the United States. With future electricity demand forecasted to grow, localized energy shortages may be experienced. Energy efficiency measures will save in energy costs and make utilities less vulnerable to electricity shortfalls due to high demand or service disruptions from natural disasters.

Recycling greywater frees up more finished water for other uses, expanding supply and decreasing the need to discharge into receiving waters. Receiving water quality limitations may increase due to more frequent droughts. Therefore, to limit wastewater discharges, use of reclaimed water in homes and businesses should be encouraged.

Conjunctive use involves the coordinated, optimal use of both surface water and groundwater, both intra- and inter-annually. Aquifer storage and recovery is a form of conjunctive use. For example, a utility may store some fraction of surface water flows in aquifers during wet years and withdraw this water during dry years when the river flow is low. Depending on whether natural or artificial aquifer recharge is employed, the required infrastructure may include percolation basins and injection wells.

• See how Tampa Bay Diversifies Water Sources to Reduce Climate Risk

An increase in the magnitude or frequency of extreme events can severely challenge water utility systems that were not designed to withstand intense events. Extreme event analyses or modeling can help develop a better understanding of the risks and consequences associated with these types of events.

• See how Camden, New Jersey Uses Green Infrastructure to Manage Stormwater

Modeling sea-level rise and storm surge dynamics will better inform the placement and protection of critical infrastructure. Generic models have been developed to consider subsidence, global sea-level rise and storm surge effects on inundation, including National Oceanic and Atmospheric Administration's (NOAA) SLOSH (Sea, Lake and Overland Surges from Hurricanes) Model and The Nature Conservancy's Coastal Resilience Tool, amongst others.

• See how Manchester-by-the-Sea, Massachusetts Assesses Climate Vulnerability

In many areas, increased water temperatures will cause eutrophication and excess algal growth, which will reduce drinking water quality. The quality of drinking water sources may also be compromised by increased sediment or nutrient inputs due to extreme storm events. These impacts may be addressed with targeted watershed management plans.

• See how Southern Nevada Water Authority Assesses Vulnerability To Climate Change

Understanding and modeling groundwater conditions will inform aquifer management and projected water quantity and quality changes. Monitoring data for aquifer water level, changes in chemistry and detection of saltwater intrusion can be incorporated into models to predict future supply. Climate change may lead to diminished groundwater recharge in some areas because of reduced precipitation and decreased runoff.

• See how Tampa Bay Diversifies Water Sources to Reduce Climate Risk

More extreme storm events will increase the amount of wet weather infiltration and inflow into sanitary and combined sewers. Sewer models can estimate the impact of those increased wet weather flows on wastewater collection system and treatment plant capacity and operations. Potential system modifications to reduce those impacts include infiltration reduction measures, additional collection system capacity, offline storage or additional peak wet weather treatment capacity.

In order to understand how climate change may impact future water supply and water quality, hydrologic models, coupled with projections from climate models, must be developed. It is important to work towards an understanding of how both the mean and temporal (seasonal) distribution of surface water flows may change. Groundwater recharge, snowpack and the timing of snowmelt are critical areas that may be severely impacted by climate change and should be incorporated into the analysis.

• See how Southern Nevada Water Authority Assesses Vulnerability To Climate Change

Intact natural ecosystems have many benefits for utilities: reducing sediment and nutrient inputs into source water bodies, regulating runoff and streamflow, buffering against flooding and reducing storm surge impacts and inundation on the coasts (e.g., mangroves, saltwater marshes, wetlands). Utilities can also work with regional floodplain managers and appropriate stakeholders to explore non-structural flood management techniques in the watershed. Protecting, acquiring and managing ecosystems in buffer zones along rivers, lakes, reservoirs and coasts can be cost-effective measures for flood control and water quality management.

Green infrastructure can help reduce runoff and stormwater flows that may otherwise exceed system capacity. Examples of green infrastructure include: bio-retention areas (rain gardens), low impact development methods, green roofs, swales (depressions to capture water) and the use of vegetation or pervious materials instead of impervious surfaces.

• See how Camden, New Jersey Uses Green Infrastructure to Manage Stormwater
• See how DC Utilizes Green Infrastructure to Manage Stormwater

Watershed management includes a range of policy and technical measures. These generally focus on preserving or restoring vegetated land cover in a watershed and managing stormwater runoff. These changes help mimic natural watershed hydrology, increasing groundwater recharge, reducing runoff and improving the quality of runoff.

It is critical that future water utility infrastructure be planned and built in consideration of future flood risks. Infrastructure can be built in areas that do not have a high risk of future flooding. Alternately, appropriate flood management plans can be implemented that involve 'soft' adaptation measures such as conserving natural ecosystems or 'hard' measures such as dikes and flood walls.

• See how Iowa City, Iowa Closes Vulnerable Wastewater Facility

Coastal wetlands act as buffers to storm surge. Protecting and understanding the ability of existing wetlands to provide protection for coastal infrastructure in the future is important considering projected sea-level rise and possible changes in storm severity.

Fire frequency and severity may change in the future, therefore it is important to develop, practice and regularly update management plans to reduce fire risk. Controlled burns, and invasive plant control help to reduce risk in wildfire-prone areas.

The electricity sector withdraws the greatest amount of water in the United States, compared with other sectors. Any efforts to reduce water usage by utilities (e.g., closed-loop water circulation systems or dry cooling for the turbines) will increase available water supply. For example, utilities may provide reclaimed water to electric utilities for electricity generation.

Agriculture represents the second largest user of water in the United States in terms of withdrawals. In order to forecast and plan for future water supply needs, agricultural (irrigation) demand must be projected, particularly in drought-prone areas. For example, to reduce agricultural water demand, utilities can work with farmers to adopt advanced micro-irrigation technology (e.g., drip irrigation).

The electricity sector represents the largest user of water in the United States in terms of withdrawals. In order to forecast future water supply needs, changes in electricity demand related to climate change must be projected.

An effective and low-cost method of meeting increased water supply needs is to implement water conservation programs that will cut down on waste and inefficiencies. Public outreach is an essential component of any water conservation program. Outreach communications typically include: basic information on household water usage, the best time of day to undertake water-intensive activities and information on access to water efficient household appliances such as low-flow toilets, showerheads and front-loading washers. Education and outreach can also be targeted to different sectors (i.e., commercial, institutional, industrial, public sectors). Effective conservation programs in the community include those that provide rebates or help install water meters, water-conserving appliances, toilets and rainwater harvesting tanks.

Increased surface water temperature may require changes to wastewater treatment systems, as microbial species used may react differently in warmer environments. Stress testing involves subjecting biological systems or bench-top simulations of systems to elevated temperatures and monitoring the impacts on treatment processes.

Changes in precipitation and runoff timing, coupled with higher temperatures due to climate change, may lead to diminished reservoir water quality. Reservoir water quality can be maintained or improved by a combination of watershed management, to reduce pollutant runoff and promote groundwater recharge and reservoir management methods, such as lake aeration.

Monitoring is a critical component of establishing a measure of current conditions, detecting deterioration in physical assets and evaluating when the necessary adjustments need to be made to prolong infrastructure lifespan.

A better understanding of weather conditions provides a utility with the ability to recognize possible changes in climate change and then identify the subsequent need to alter current operations to ensure resilient supply and services. Observations of precipitation, temperature and storm events are particularly important for improving models of projected water quality and quantity.

Understanding and modeling the conditions that result in flooding is an important part of projecting how climate change may drive change in future flood occurrence. Monitoring data for sea level, precipitation, temperature and runoff can be incorporated into flood models to improve predictions. Current flood magnitude and frequency of storm events represent a baseline for considering potential future flood conditions.

Understanding surface water conditions and the factors that alter quantity and quality is an important part of projecting how climate change may impact water resources. Monitoring data for discharge, snowmelt, reservoir or stream level, upstream runoff, streamflow, in-stream temperature and overall water quality can be incorporated into models of projected supply or receiving water quality.

• See how Southern Nevada Water Authority Assesses Vulnerability To Climate Change

Changes in vegetation alter the runoff that enters surface water bodies and the risk of wildfire to facilities within the watershed. Monitoring vegetation changes can be conducted by ground cover surveys, aerial photography or by relying on the research from local conservation groups and universities.

Adequate insurance can insulate utilities from financial losses due to extreme weather events, helping to maintain financial sustainability of utility operations.

An important step in developing an adaptation program is educating staff on climate change. Staff should have a basic understanding of the projected range of changes in temperature and precipitation, the increase in the frequency and magnitude of extreme weather events for their region and how these changes may affect the utility's assets and operations. Preparedness from this training can improve utility management under current climate conditions as well.

• See how Southern Nevada Water Authority Assesses Vulnerability To Climate Change

Coastal restoration plans may protect water utility infrastructure from damaging storm surge by increasing protective habitat of coastal ecosystems such as mangroves and wetlands. Restoration plans should consider the impacts of sea-level rise and development on future ecosystem distribution. Successful strategies may also consider rolling easements and other measures identified by EPA's Climate Ready Estuaries program.

Emergency response plans (ERPs) outline activities and procedures for utilities to follow in case of an incident, from preparation to recovery. Some of the extreme events considered in ERPs may change in their frequency or magnitude due to changes in climate, which may require making changes to these plans to capture a wider range of possible events.

Energy management plans identify the most critical systems in a facility, provide backup power sources for those systems and evaluate options to reduce power consumption by upgrading to more efficient equipment. Utilities may develop plans to produce energy, reduce use and work toward net-zero goals.

Beyond the establishment of water trading in times of water shortages or service disruptions, these agreements involve the sharing of personnel and resources in times of emergency (e.g., natural disasters).

Operational measures to isolate and protect the most vulnerable systems or assets at a utility should be considered. For example, critical pump stations would include those serving a large population and those located in a flood zone. Protection of these assets would then be prioritized based on the likelihood of flood damage and the consequence of service disruption.

• See how Anacortes, Washington Rebuilds Water Treatment Plant for Climate Change

Plans to build or expand infrastructure should consider the vulnerability of the proposed locations to inland flooding, sea-level rise, storm surge and other impacts associated with climate change.

• See how Anacortes, Washington Rebuilds Water Treatment Plant for Climate Change
• See how Blue Plains Wastewater Facility in Washington DC Reinforces Facility Against Floods
• See how DC Utilizes Green Infrastructure to Manage Stormwater
• See how Iowa City, Iowa Closes Vulnerable Wastewater Facility

Effective adaptation planning requires the cooperation and involvement of the community. Water utilities will benefit by engaging in climate change planning efforts with local and regional governments, electric utilities and other local organizations.

Drought leads to severe pressures on water supply. Drought contingency plans would include the use of alternate water supplies and the adoption of water use restrictions for households, businesses and other water users. These plans should be updated regularly to remain consistent with current operations and assets.

• See how Fredericktown, Missouri Prepares for Climate Change Drought Risk

Post-disaster policies should minimize service disruption due to damaged infrastructure. These contingency plans should be incorporated into other planning efforts and updated regularly to remain consistent with any changes in utility services or assets.

• See how Iowa City, Iowa Closes Vulnerable Wastewater Facility

As sea level rises, saltwater may intrude into coastal aquifers, resulting in substantially higher treatment costs. The injection of fresh water into aquifers can help to act as a barrier, while intrusion recharges groundwater resources.

• See how Tampa Bay Diversifies Water Sources to Reduce Climate Risk

Sea-level rise and coastal storm surge can cause wastewater outlets to backflow. To prevent this, stronger pumps may be necessary.

• See how Southeast Florida Compact Analyzes Sea Level Rise Risk

Precipitation variability will increase in many areas. Even in areas where precipitation and runoff may decrease on average, the distribution of rainfall patterns (i.e., intensity and duration) can change in ways that impact water infrastructure. In particular, more extreme storms may overwhelm combined wastewater and stormwater systems.

• See how Iowa City, Iowa Closes Vulnerable Wastewater Facility

Existing water treatment systems may be inadequate to process water of significantly reduced quality. Significant improvement to existing treatment processes or implementation of additional treatment technologies may be necessary to ensure that quality of water supply (or effluent) continues to meet standards as climate change impacts source or receiving water quality.

• See how Southern Nevada Water Authority Assesses Vulnerability To Climate Change

Higher surface temperatures may make meeting water quality standards and temperature criteria more difficult. Therefore, to reduce the temperature of treated wastewater discharges, additional effluent cooling systems may be needed.

In areas where streamflow declines due to climate change, water levels may fall below intakes for water treatment plants.