Climate change: Effects on reef island resources
The salinity, depth, quantity, and reliability of fresh groundwater resources on coral reef islands and coastlines are environmentally important parameters. Groundwater influences or controls the terrestrial flora, salinity, and nutrient levels in the near-shore benthic environment, the rate and nature of sediment diagenesis, and the density of human habitation. Data from a number of Indo-Pacific reef islands suggest that freshwater inventory is a function of rainfall and island dimensions. A numerical model (SUTRA) has been used to simulate the responses of atoll island groundwater to changes in recharge (precipitation), sea level, and loss of island area due to flooding. The model has been calibrated for Enjebi Island, Enewetak Atoll, where a moderately permeable, water-table aquifer overlies a high-permeability formation. Total freshwater inventory is a monotonic but nonlinear function of recharge. If recharge and island area are constant, rising sea level increases the inventory of fresh water by increasing the useful volume of the aquifer above the high-permeability zone. Flooding of land area reduces the total freshwater inventory approximately in proportion to the loss of recharge area. The most significant results of the model simulation, however, are the findings that the inventory of low-salinity water (and by extrapolation, potable water) is disproportionately sensitive to changes in recharge, island dimensions, or recharge. Island freshwater resources may therefore be unexpectedly vulnerable to climate change.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA); San Jose State Univ., CA (USA). Dept. of Geology
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6860163
- Report Number(s):
- UCRL-98880; CONF-880873-3; ON: DE88014145
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Terrestrial-- Site Resource & Use Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
AQUIFERS
ATMOSPHERIC PRECIPITATIONS
AVAILABILITY
CLIMATES
COMPUTER CODES
ENIWETOK
ENVIRONMENTAL IMPACTS
EVALUATION
GEOLOGIC STRUCTURES
GROUND WATER
HYDROGEN COMPOUNDS
ISLANDS
MARSHALL ISLANDS
MATHEMATICAL MODELS
MICRONESIA
OCEANIA
OXYGEN COMPOUNDS
RAIN
RECHARGE
REEFS
RESPONSE MODIFYING FACTORS
S CODES
WATER
WATER TABLES