Climate Change Threat Sea-Level Rise 1

Potential Impacts from Sea-Level Rise How might our community be impacted by sea-level rise? 2

Sea-Level Rise Impacts: Saltwater Intrusion 3

Extreme Event Example: Saltwater Intrusion on the Louisiana Coast In September 2005, Hurricane Rita affected Texas and Louisiana as a Category 3 hurricane A storm surge of at least 15 feet (4.6 meters) flooded parts of Cameron, Jefferson Davis, Terrebonne and Vermillion parishes. Damage included: Nearly $300 million in losses to sugar cane crops Saltwater intrusion into groundwater 4

Adaptation Options for Saltwater Intrusion Conduct sea-level rise and storm surge modeling Manage or acquire ecosystems in buffer zones for flood control and water quality management Monitor groundwater quality and model potential future conditions Implement saltwater intrusion barriers and aquifer recharge; consider using reclaimed water to create saltwater intrusion barriers Install hard or natural barriers Install low-head dams to separate saltwater from intakes upstream in the freshwater pool Increase treatment capabilities 5

Adapting to Saltwater Intrusion Example: Los Angeles County Flood Control District (LACFCD) Groundwater extractions in the LA area were double the natural replenishment rate, which lowered groundwater levels to 100 feet below sea-level In 1951, the LACFCD injected potable water into a well to test if pressure could block the intrusion of seawater (groundwater injection barrier) 6

Adapting to Saltwater Intrusion (cont’d) Example: Los Angeles County Flood Control District (LACFCD) Three barrier projects were constructed: West Coast Basin Dominguez Gap Alamitos Gap The projects have successfully protected freshwater aquifers in the Los Angeles Basin for more than 50 years 7

Sea-Level Rise Impacts: Coastal Storm Surge 8

Extreme Event Example: Hurricane Ike – Texas Coastal Storm Surge 9

Adaptation Options for Coastal Storm Surge Conduct sea-level rise and storm surge modeling Manage or acquire ecosystems in buffer zones for flood control and water quality management Ensure critical assets have backup power sources Update emergency response plans to include flooding contingencies Join a mutual aid network, such as WARN Build flood barriers such as sea walls, levees or other structures to protect infrastructure Relocate facilities to higher ground 10

Adaptation Options for Coastal Storm Surge (cont’d) Implement policies for post- flood repairs to minimize service disruption due to damaged infrastructure Improve pumps for backflow prevention to wastewater outlets 11

Adapting to Coastal Storm Surge Example: Planning in New York City Storm surge from Hurricane Sandy in 2012 damaged infrastructure, caused severe beach erosion and flooding Coastal protection plan developed to protect coastal assets Measures under consideration: Beach nourishment Wetland restoration Sea walls Tide gates Storm surge barriers or levees 12

Sea-Level Rise Impacts: Loss of Coastal Landforms and Wetlands 13

Extreme Event Example: Hurricane Katrina – Gulf Coast and Inland 14

Adaptation Options for Loss of Coastal Landforms and Wetlands Conduct sea-level rise and storm surge modeling Manage or acquire ecosystems in buffer zones to minimize storm surge damage to coastal landforms or wetlands Develop coastal restoration and protection plans Build flood barriers, such as sea walls, levees or other structures to protect infrastructure Implement barriers and aquifer recharge to limit effects of saltwater intrusion; consider using reclaimed water to create saltwater intrusion barriers 15

Adapting to Loss of Coastal Landforms and Wetlands Example: USGS’s Sea-Level Rise Hazard and Decision Support Project Future sea-level rise impacts will be significant and include: Land loss from inundation and erosion Migration of coastal landforms Increased elevation, duration and frequency of storm surge flooding Wetland losses Changes in coastal aquifer hydrology and coastal habitats Coastal vulnerability assessments should consider physical, biological and social factors, as well as the ability of society and its institutions to adapt to change 16

Adapting to Loss of Coastal Landforms and Wetlands (cont’d) Example: USGS Sea-Level Rise Hazard and Decision Support Project The USGS project: Synthesizes information on coastal environments, processes and uncertainties Uses a Bayesian statistical analysis framework This statistical approach allows researchers to evaluate the probability of a number of sea-level rise impacts 17

Adapting to Loss of Coastal Landforms and Wetlands (cont’d) Example: USGS Sea-Level Rise Hazard and Decision Support Project This statistical approach enables scientists to make probabilistic projections of the future state of coastal environmental outcomes The ability to communicate the projections can support decision making for addressing sea-level rise 18

Community and Economic Impacts Service disruptions can cause customers to lose confidence in their utility’s ability to provide clean and safe water to customers Local businesses suffer and may lose revenue if they lack reliable access to water or sewer services What can be done? Collaborate with other community partners to develop more sustainable community and regional plans Discuss adaptation options with local businesses Work with local government to communicate adaptation activities and plans to customers 19