Isotope Hydrology: Tools to unlock waters secrets
Water resources are being increasingly stressed by multiple factors, including growing population, grater food production, irrigated agriculture, energy production and climate variability and change. One billion people around the world currently have no access to safe drinking water and only about 15% of the worlds population enjoy relative abundance.
A key requirement for assuring adequate water supplies and their sustainable management is to improve the assessment of water resources. Such assessments are severely lacking in most of developing countries. The greatest proportion of the earths available fresh water is located underground, and this vital resource is often poorly understood and poorly managed.
Applications of Isotope Techniques in Water Management and Dam Safety
Isotope techniques allow rapid understanding of hydrological systems that may otherwise require years or decades of monitoring. Therefore it is cost effective. In some cases it is unique.
Isotopes are commonly employed to investigate:
- Recharge Mechanism of groundwater:
- Identification of groundwater recharge sources
- Recharge areas
- Mixing of different water sources
- Groundwater Dating:
- Identification of modern recharge
- Groundwater movement and residence time
- Infiltration rates in unsaturated zone
- Identification of paleowaters
- Delineation of protection zones
- Groundwater pollution and salinization:
- Identification of pollution sources
- Origin of nitrates
- Origin of groundwater salinity
- Microbial denitrification processes
- Mixing of sea water
- Surface water/groundwater relationship and interconnection between aquifers
- Dam safety & sustainability:
- Leakage /seepage problems
- Effect of dam reservoir on surrounding areas
- Investigation of geothermal resources:
- Source of thermal waters
- Residence time
- Subsurface history (rock-water interaction, mixing with fresh water)
- Estimation of reservoir temperature
Most commonly used isotopes are 2H1 , 3H1 , 18O8 , 13C6 , 14C6 , 15N7 and 34S16
Further Reference