97% of the world’s freshwater, used to provide water for urban, rural, and industrial areas, comes from groundwater. It supplies over two billion people with drinking water and irrigation water.
Indians are the largest users of groundwater in the world, as they have constructed millions of private wells in the past five decades (Héctor Garduño et al, 2011). Surface water is in high demand, which is increasing the use of groundwater. In underdeveloped countries such as Nigeria, the usage has increased due to the nonexistence of a state water supply and availability of cheap drilling equipment and technology.
In 2011, UNICEF reported that about seventy million Nigerians lacked access to safe water, and 40% of rural areas in various states have non-functioning water supply systems. It is no surprise that drilling boreholes in Nigeria is the norm. There are several reasons boreholes have come to stay in Nigeria, such as:
- Poor service delivery from the Government on water supply.
- Convenient irrigation system for farmers
Water borehole is a hole dug into the ground for the provision of the flow of water into the hole, which then allows an installed pump to transfer the water into a reservoir. This process is called water abstraction.
The exploitation of groundwater via borehole has been helpful to Nigerians for the stable supply of water. However, it has now become an environmental issue that needs to be addressed. The continuous drawing of water from underground has led to the depletion of groundwater levels, which causes a decrease in the discharge of groundwater to rivers and lakes. Thereby, causing rivers to dry up and wetlands no longer sustainable.
Change in climate and population increase will keep the demand on boreholes on the increase, which has socio-economic effects on the country and environmental effects as well. There’ll come a time when overexploitation will have occurred and led to a drop in the level of groundwater which will lead to an unattainable abstraction.
According to AWDROP (Association of Water Well Drilling Rig Owners & Practitioners), about fifty foreign drilling companies have companies round Nigeria, most of them Asians, and they drill three or more daily. An estimation of about 400 boreholes are drilled daily. Some of the companies are not licensed. The drilling design used by most of these foreigners are not sustainable for Nigeria, and the water gets contaminated after 2 or 3 years.
Negative Cumulative Impacts of Borehole Drilling
1. Saline Intrusion
Saline (the sterile mixture of salt and water) intrusion occurs when a higher density of seawater flows into freshwater. Continuous withdrawals or digging for boreholes from the aquifers causes vertical and lateral intrusion of the surrounding salt water.
2. Deterioration in Water Quality
An area called water table is an area saturated with freshwater. The water level declines because of the constant pumping of water. Another reason for the deterioration in water quality is the lack of maintenance of water wells. The pH and total dissolved solids levels are not tested, thereby leaving people to drink contaminated water. The presence of sand and other sediments result in cloudiness, leading to poor water quality.
3. Induced Pollution
When a well has been unused for a while, chemicals are used by drilling agencies to dissolve the in-crusting materials present in the well. These chemicals become resident in the water. Subsequently, the water is used for cooking, drinking or irrigation purposes. Pollutants such as arsenic, fluoride, lead, nitrates and other organic compounds are found in groundwater. These are a major source of pollution.
4. Land Subsidence
Land subsidence can be defined as the sinking of the surface or land because of groundwater extraction. It can also be described as the lowering of land surface elevation from changes that have taken place. This is a major problem in Nigeria, as a lot of land surfaces have caved in due to the drilling of boreholes. Over-exploitation is the main cause of subsidence in Nigeria, when the groundwater is constantly pumped even when the water level is low. It brings about the lowering of the land surface.
The effect of subsidence transcends beyond the sinking of land. It leads to damage of roads, canals, sewers and bridges; and the changes in the elevation of drainage and streams. It can affect farmlands and crops.
5. Financial Impact
As stated earlier the number of boreholes that are drilled daily and monthly are a lot. It is quite expensive to drill, and the price keeps going up. Private houses have boreholes, almost every house in urban cities have boreholes. The amount spent on constructing individual boreholes can be used to build a reliable source of water from surface water which is safer and environmentally friendly.
6. Health Impact
Water from the underground is unsafe for human consumption because most of the boreholes are exposed to pollutants and pathogens which leads to water-borne diseases such as typhoid, guinea worm, diarrhoea, e-coli, etc. Heavy metals present in groundwater are carcinogenic and have adverse effects on the human body.
1. Policy Implementation
With the help of the government, policies can be put in place to control or regulate the drilling of boreholes in specific locations. For example, giving a limit to the number of boreholes in a community or maximum amount of water that can be withdrawn in a day to avoid over abstraction. Licensing is also a way to avoid land subsidence and reduce the impact on the environment. A three-way step for policy implementation is:
- Set objectives: This answers the question of what the policy would entail, what is to be achieved.
- Monitoring: A very important step. When the policies have been established, it is important to follow up and ensure people are adhering to the rules set in place.
- Enforce compliance: Some drillers might find it difficult to comply, but it is necessary to ensure they do by putting penalties for offenders will put them in line.
2. Communal Boreholes
This is a temporary solution, but it is still a way out. The provision of boreholes for communities instead of individuals. The advantage of this is the Local Government in the area can contribute to finding the suitable location for the borehole. This will tackle the problem of private residences drilling boreholes close to soakaways which brings about leakage.
3. Abstraction licensing
Licensing entails giving borehole operators and drillers the license to carry out their duty. This is paramount because a lot of foreign drilling companies are not licensed to operate and yet they have several clients. This will restrict the functionality of unlicensed drillers and fear of sanction will prompt them to get their license.
In conclusion, borehole drilling is a menace to the society and the environment. And if not curtailed, it will be a canker-worm eating the environment slowly.
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