Geological & Hydro-geological Studies in EIA play a crucial role as they help to identify and assess potential risks and hazards associated with a proposed project. These studies help evaluate the proposed project site’s geological and hydrological conditions, including potential hazards such as earthquakes, landslides, and groundwater contamination. Conducting geological and hydro-geological studies during the EIA process can identify and address potential problems before the implementation stage. This helps to prevent any degradation of the environment and reduces the risk of harm to human lives. In addition, these studies help to evaluate the disaster resilience capacity of the communities within the project area, which is important in hazard mitigation. By quantifying the risk and assessing the disaster vulnerability profile of a site, appropriate strategies can be developed to minimize hazard susceptibility and preserve the natural environment.
Geological Threats in Geological & Hydro-Geological Studies in EIA
Geological threats refer to potential hazards that arise from a site’s geological and hydrological features, and these threats must be assessed during an Environmental Impact Assessment (EIA) study. The geological threats that need to be considered during an EIA study are as follows:
- Compressible Ground and Shrink-Swell Soil: Some soils, such as clay soils, can shrink and swell due to moisture changes, damaging structures built on top of them.
- Slope Instability and Landslides: Slope instability can occur due to natural processes such as erosion or due to human activities such as excavation or construction. This can result in landslides[1], which can cause damage to structures and pose a threat to human life.
- Ground Dissolution: The dissolution of soluble rocks such as limestone and gypsum can result in the formation of sinkholes or subsidence, which can cause damage to structures built on top of them.
- Liquefaction and Collapse: This can occur in areas with loose or sandy soil during an earthquake or other seismic activity. The soil loses its strength and stiffness, causing it to behave like a liquid, which can lead to the collapse of structures built on top of it.
- Fluvial, Coastal, and Groundwater Flooding: Flooding due to rivers, coastal erosion, or rising groundwater can significantly threaten infrastructure and human life.
- Aggressive Ground Conditions: This includes areas with high levels of chemical or biological contamination, such as landfills, which can threaten human health and the environment.
- Mining Hazards: This includes the potential for mine subsidence, collapse, or water pollution due to mining activities.
Importance of Geological & Hydro-Geological Studies in EIA
The importance of geological and hydro-geological studies in an EIA are:
- Hydro-geological surveys are crucial to determine the quantity and quality of underground water available at a specific location.
- Underground water is considered an excellent source of drinking water compared to surface water due to lower pollution risk and natural purification as it flows through sand and stone.
- Borewells help in reducing the possibility of contamination.
- Regardless of the season, the water temperature is always desirable, and during summers, the water availability is higher as sources are located at deeper levels.
- Groundwater is a sustainable option that could help solve the water crisis in regions where pure and unpolluted water is scarce.
- Hydro-geological survey methods can recognize groundwater sources, predict produce and water quality.
- Assessing the subsurface layer of rocks provides critical information about the future utility of groundwater.
- A hydro-geological survey report is necessary to provide sound recommendations for borehole drilling to acquire high-quality groundwater for human consumption.
Structure of Geological & Hydro-Geological Studies in EIA
The structure of a hydro-geological survey report typically includes the following elements:
- Title page
- Signature page
- Table of contents, tables, figures, and appendices lists
- Introduction
- Purpose and description of hydrogeologic systems
- Data collection methods
- Analysis of groundwater use and development methods and procedures
- Hydrogeologic evaluation
- Documentation of numerical models (if modelling is performed)
- Water quality findings
- Recommendations (if required)
- Report restrictions
- Sources of information and references
- Appendices, tables, and figures
Documents Required In Geological & Hydro-Geological Studies in EIA
Documentation required in Geological & Hydro-geological Studies in EIA should include the following:
- The goals and scope of the project.
- Documentation of data collection.
- Site Overview, including the geologic and hydrogeologic settings and surface characteristics.
- Information on seismic activity.
- Sources of information used in the study.
- Figures and tables of data collected.
- Analysis of the impact on groundwater.
- Description of data collection methods used in the field.
- Methods and reports for laboratory testing.
- Hypotheses formulated during the study.
- Conclusions are drawn from the data analysis.
- Recommendations based on the study’s findings.
Conclusion
Incorporating geological and hydro-geological studies in the EIA process is essential for identifying and mitigating potential risks and hazards associated with a proposed project. These studies provide valuable subsurface information that can inform decision-making during geohazard-prone project sites’ pre- and post-construction phases. Including hydrological, geotechnical, and geological considerations in the EIA process, preventive measures, appropriate environmental remediation, and protection can be integrated and implemented early on, leading to sustainable use of natural resources. Although incorporating these considerations may come with an additional cost, the repercussions of an environmental disaster resulting from neglecting geological and geotechnical aspects in the EIA could lead to a more severe budget expenditure and environmental problems. Therefore, including geological and hydro-geological studies in the EIA process is necessary to ensure that engineering projects do not adversely impact the environment and that natural resources are used sustainably. Strict compliance with relevant policies and regulations of relevant authorities is also crucial in protecting the environment.
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