Background / Sea Level Rise and

Don’t hesitate to comment below if you have any questions or additional phrases
Sea Level Rise and Groundwater Sourced Community Water Supplies in Florida CCSP Workshop: Climate Science in Support of Decision MakingNovember 14, 2005Randall Freed, ICF ConsultingJohn Furlow, Susan Herrod Julius,US EPA Global Change Research Program
,Background Sea Level Rise is among the most certain impacts of climate change
Salt water intrusion is directly tied to sea level Community Water Supplies (CWS) are among the highest-value uses of water Site-specific hydrogeological assessment and monitoring is resource-intensive Decision support is needed to set priorities for assessing and protecting CWS ,Objectives Develop screening tools to characterize
Vulnerability of groundwater-supplied CWS to saltwater intrusion
Reliance on current aquifer Develop a priority-setting framework based on vulnerability and aquifer reliance Demonstrate the framework with coastal CWS in FL ,Relevance to CWS in Florida Very high reliance on GW (~93% of population)
Strong water resource management programs Excellent availability of data Lat and long of CWS
DRASTIC scoring of aquifers Concern about salt water intrusion Source: Fernald, E.A., and E.D. Purdum, 1998. Water Resources Atlas of Florida. Institute of Science and Public Affairs, FSU
,Assessing Vulnerability DRASTIC developed by EPA & Nat’l Water Well Assoc in 1987
Widely applied to evaluate vulnerability to contamination Basic assumption: contamination is introduced at the ground surface and leaches into ground water via infiltration Modified to account for saltwater intrusion caused by sea level rise, which intrudes laterally (or in some cases upward) into aquifers ,Modifying DRASTIC Modified system: SLR Vulnerability =
D + R + A +T + I + C + M + P, where D (Depth to Water) ranges from 1 (0-5 ft.) to 10 (100+ ft.)
R (Net Recharge) ranges from 10 (0-2 in./yr) to 2 (10+ in./yr) A (Aquifer Media) ranges from 2 (massive shale) to 10 (karst limestone) T (Topography) ranges from 1 (18% slope) to 10 (0-2% slope) I (Impact of Vadose Zone) ranges from 10 (confining layer) to 1 (karst limestone) C (Conductivity) ranges from 1 (1-100 gpd/sq.ft.) to 10 (2000+ gpd/sq.ft.) M (Miles to Coastline) ranges from 1 (more than 4.35 miles) to 10 (less than 0.31 miles) P (Potentiometric Surface, i.e., water-table elevation) ranges from 1 (greater than 3 feet) to 10 (less than 0.5 feet) Original system — vulnerability to surface pollution = D + R + A + S + T + I + C, where:
D – Depth to Water
R – Net Recharge A – Aquifer Media S – Soil Media T- Topography I – Impact of Vadose Zone C – Conductivity ,Evaluating Aquifer Reliance Reliance = 2 * log(Pop served) + AWS
Population served Min = 25 (for a mobile home park)
Max = 475,000 (for Tampa) Availability of alternative water supplies (AWS) Biscayne Aquifer (designated by SDWA as sole-source aquifer) = 10
Water resource caution areas (designated by regional water management districts) = 5 All others = 1 ,Vulnerability and Reliance ,Florida Community Water Systems: Vulnerability and Reliance Ratings Mapping Vulnerability and Reliance
,Pensacola ,Miami – Palm Beach ,Findings Key Findings
High vulnerability/ high reliance CWS concentrated in Pensacola and Miami-Palm Beach areas
Vulnerability index results appear to be consistent with known occurrences of salinity due to salt water intrusion Index could be simplified (to drop some DRASTIC factors) and still provide valid results – M and P are most important Limitations Applicability to confined aquifer systems
Utility when data availability is limited ,Next Steps Identify decision makers best positioned to use this index
Apply index to other states in Gulf Coast Region and Mid-Atlantic Region Develop risk management guidance based on the priority setting framework; identify decision points and actions (site-specific monitoring and risk assessment, long-term planning for alternate supplies, hydraulic controls) ,Contact Information For more info: Randy Freed ICF Consulting