Water resources are also affected by the negative effects of climate change. Many scientists will be assessing the consequences of climate change on groundwater. Groundwater is studied by hydrogeology. Therefore, it is essential to understand hydrogeology and how climate change affects underground water resources.
In this article we are going to tell you what hydrogeology is and how climate change affects underground water resources.
What is hydrogeology
Hydrogeology is a branch of geology that focuses on the study of groundwater and its interaction with the Earth. In other words, it deals with understanding how water is stored underground and how it flows through subsurface geological formations . This discipline is essential for understanding the availability and quality of groundwater, as well as its importance in the hydrological cycle and in meeting human and ecological needs.
Hydrogeologists, experts in this area, use a variety of tools and techniques to investigate and map aquifers (underground water reservoirs) and the layers of rock and sediment that store and transmit groundwater. They also study how human activities, such as drinking water extraction, agriculture or construction, can influence the flow and quality of groundwater.
Hydrogeology is crucial for the sustainable management of water resources, as it helps prevent the overexploitation of aquifers, saltwater intrusion into freshwater aquifers, and groundwater contamination by chemicals and pollutants . Furthermore, it plays a fundamental role in identifying sources of drinking water and in assessing the feasibility of water-related engineering projects, such as well drilling, aquifer rehabilitation, and wastewater management.
Hydrogeology and how climate change affects groundwater resources
Groundwater (contained in sediments and rocks) is the most important freshwater reservoir on Earth, typically stored for periods ranging from decades to hundreds or even thousands of years. Therefore, groundwater resources serve as an excellent buffer against the impacts of climate change on surface water supplies, as aquifer systems often contain significant and dispersed reserves . However, this raises questions about the extent to which groundwater reserves themselves naturally adapt to global changes and whether we are doing enough to help protect them.
Groundwater enters and leaves underground aquifer systems and its storage increases or decreases due to changes in this balance, which changes over time and is controlled by natural conditions and human activities:
- Entrances to charging areas, primarily through excess precipitation and infiltration into surface water bodies and agricultural irrigation practices (and more through urban water leaks and wastewater treatment).
- Natural discharges from springs and water courses, wetlands and lagoons and well extractions.
Before large-scale human activity (at least before 1850 and in many areas before 1950), the human impact on groundwater systems (in terms of modification, extraction, and pollution) was minimal compared to available resources. Most aquifer systems exhibit a good balance between recharge and drainage, and the natural quality of groundwater is generally good , but factors such as population growth, agricultural intensification, urbanization/industrialization, and climate change have increased groundwater stress.
In the future, groundwater depletion and degradation and its impact on environmental heritage will need to be carefully considered when assessing the social sustainability of human activities.
What effects could global warming have on groundwater?
Estimating current groundwater recharge rates (and predicting future recharge rates) is crucial when considering resource sustainability: in areas of greater drought, recharge by precipitation is less important than indirect recharge by surface runoff and occasional recharge by human activities.
There remains considerable uncertainty about the exact impact of global warming on groundwater recharge in different regions. On the one hand , an increase in ambient temperature will lead to less frequent but more intense rainfall, and possibly an increase in recharge (which will offset the increase in evapotranspiration), so that in some fractured aquifers (which have little water storage capacity), the groundwater level will rise. It may rise to levels higher than those recorded so far, causing damage to property and crops.
On the other hand, if rainfall is less but of greater intensity, soil moisture will decrease, which can cause erosion and the formation of gullies, or compact the soil, which reduces infiltration capacity and, therefore, reduces recharge. of the aquifers.
Slow changes
Surprisingly, the “natural rates” of climate and land cover change often experienced over the past 400.000 years are slower than human-induced changes . The projected minimum rate of global warming is approximately 10 times greater than previously recorded, raising concerns about its impact on groundwater recharge, particularly in low-storage aquifers in the tropics upon which millions of people depend.
However, given the storage inertia in many large aquifers, only long-term sustained climate change will have a significant impact on available groundwater reserves.
Increased groundwater extraction and some major land-use changes can have significant impacts on groundwater recharge and quality within decades. Therefore, land-use changes and groundwater extraction must be considered when assessing the combined effects of future global warming.
I hope that with this information you can learn more about hydrogeology and how climate change affects underground water resources.