The adaptation strategies provided below are intended to inform and assist communities in identifying potential alternatives. They are illustrative and are presented to help communities consider possible ways to address anticipated current and future climate threats to water utilities.
Adaptation Strategies for Protecting Water Utilities
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Construct New Infrastructure
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.
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.
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.
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.
Increase System Efficiency
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.
Model 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.
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.
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.
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.
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.
Modify Land Use
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.
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.
Modify Water Demand
Monitor Operational Capabilities
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.
Plan for Climate Change
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.
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.
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 Washington D.C. Utilizes Green Infrastructure to Manage Stormwater
- See how Iowa City, Iowa Closes Vulnerable Wastewater Facility
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.
Repair and Retrofit Facilities
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.
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.
Sea-level rise and coastal storm surge can cause wastewater outlets to backflow. To prevent this, stronger pumps may be necessary.
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.
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.
These strategies are adapted from existing U.S. Environmental Protection Agency, Centers for Disease Control and Prevention and other federal resources. Please view these strategies in the context provided by the primary source document:
The adaptation strategies provided are intended to inform and assist communities in identifying potential alternatives. They are illustrative and are presented to help communities consider possible ways to address current and future climate threats to contaminated site management.