Advantages of dams include flood control, pollution control, hydroelectricity generation, water conservation, recreational use, navigation, water supply, job creation, tourist attraction, and food production. Disadvantages of dams include ecologic disruption, potential failure, displacement, cost, environmental impact, conflict, and maintenance challenges.
This article discusses the advantages and disadvantages of dams, as outlined below;
Advantages of Dams
1). Flood Control as one of the Advantages of Dams
Flood-control is a major application of dams.
The two mechanisms by which dams control flooding are by changing water levels and by altering water-flow patterns.
Rather than result in a natural hazard, excessive precipitation and stormwater are either stored or diverted when a dam is present. The water is therefore utilized for other purposes like irrigation and domestic supply.
Dams can also release flood waters when precipitation and water levels have declined .
By controlling flood water, dams help to mitigate the risks of pollution, as well as loss of life and property.
2). Pollution Control as one of the Advantages of Dams
Dams are used to control pollution.
This may occur in any of various forms. One of these is through the impoundment of mine waste by a tailings dam .
Given the toxic characteristics of mine waste, a tailings dam, which restricts the mobility of this waste and its spread in the environment, can be seen as a waste management tool. The use of dams to impound mine waste also reduces the need and complexity of environmental remediation.
Another method by which dams control pollution, is by removing debris from water in streams and rivers as it flows downstream. The types of dams used for this purpose include debris dam and check dam .
In addition to restricting the mobility and spread of toxic materials, dams can reduce the risk of geologic hazards that cause environmental degradation, such as mudslides.
3). Hydroelectricity Generation
Dams are also used for electricity generation.
In these power plants, the dam acts as a tool for impounding and controlling the flow of water, by which means kinetic energy is produced and used to drive the mechanical turbine of an electric generator, thereby generating electricity.
Hydroelectricity is itself an important form of power. It is derived from renewable energy sources and is therefore sustainable compared to non-renewable power from fossil fuels. Hydroelectricity is also clean, as it does not release any significant amounts of greenhouse gases into the atmosphere.
Approximately 20 percent of global power supply comes from hydropower plants.
4). Water Conservation
One of the ways this is achieved is through storage. Working alongside reservoirs, dams store water which would otherwise be lost as stormwater-runoff during periods of high precipitation. The stored water can be put to use in the dry season when it is needed.
Dams such as the underground dam, conserve groundwater resources by reducing the rate of evaporation and depletion .
Another way by which dams conserve water is through the mitigation of pollution.
5). Recreational Use as one of the Advantages of Dams
Dams serve multiple purposes, one of which is recreation.
The environments within which many large dams occur, are excluded from human residential areas, and are used as recreational resorts.
Reservoirs in which water impounded by the dam is stored, may be used for fishing, waterskiing and boating. The environs may also be used for camping.
6). Navigation Optimization
A practical example of the advantages of dams is their role in optimizing water navigation.
When dams are constructed and deployed, they are usually capable of changing the flow pattern for water within their scope of influence. These changes may affect the level of water as well as its flow direction.
Changing the water level within some areas can improve navigation, especially in cases where the water level is increased. Water navigation pathways which were formerly unstable due to unfavorable water levels may thereby be stabilized.
Dams also affect and control water flow direction. This can improve the efficiency transport by defining a safe water course for vessels to navigate.
The influence of dams also makes it easier to monitor and maintain water routes, and reduces the prevalence of factors like sedimentation that reduce navigation efficiency.
7). Sustainable Water Supply as one of the Advantages of Dams
The construction of dams is one of the measures which can help to establish sustainability of water supply.
Various types of dams such as storage dams, may operate alongside water reservoirs, to retain water during floods or high tides .
The act of water storage which is facilitated by these dams, prevents wastage in the form of runoff and flood. The stored water may be used productively during periods of low tide and low precipitation.
Storage and subsequent utilization of water by dams, leads to sustainable supply for industrial, commercial and agricultural purposes.
8). Job Creation as one of the Advantages of Dams
At both construction and operation stages, water dam projects provide job opportunities.
During construction, these opportunities would include planning, building, supervision, and regulation.
The operation stage may provide opportunities in maintenance and engineering.
These job opportunities serve as an avenue of economic growth both locally and beyond.
9). Dams may Serve as Tourist Attraction Sites
Artificial reservoirs which are built with many dams may be used as tourist attractions.
Other features within the vicinity of dams, such as hilly terrains and forests also contribute to the attractive characteristic of these dams.
As a tourist attraction site, a dam increases its economic value to the government and populace of its resident region. Commercial activities in lodging and recreation may also thrive at such sites.
10). Agriculture and Food Production
Dams support agriculture mainly by conserving water for agricultural production .
Water which is conserved by dams can be used to provide a sustainable supply for irrigation purposes in agricultural lands.
In addition to being used within the vicinity of the dam, such water can be diverted through channels or canals, to distant areas where it is needed.
A sustainable supply of water such as can be provided by dams, is helpful in soil conservation projects like crop rotation, and similar endeavors for improving agricultural yield. These endeavors are in turn applicable to tackle food insecurity and world hunger.
Disadvantages of Dams
1). Ecologic Disruption as one of the Disadvantages of Dams
The construction and operation of dams can disrupt the natural function of ecosystems, causing systemic imbalances.
One of the reasons why this occurs is because dams restrict natural water flow. Such restrictions can be harmful to aquatic life, by reducing the volume of dissolved oxygen in water, while increasing the concentration of carbon dioxide and methane .
Dams also alter the natural flow patterns of streams and rivers. This can affect the migration habits of fish and other aquatic organisms. In cases where migration is linked to essential activities like feeding and mating, such changed can be detrimental to the survival of the affected organisms.
On a large spatial and temporal scale, dams can reduce the diversity of aquatic organisms by altering natural succession patterns in the ecosystem, as well as the natural transfer of energy and biomass across the trophic levels of the energy pyramid.
Dams can also destroy existing ecosystems through basin expansion and associated processes of flooding and erosion.
2). Potential Failure as one of the Disadvantages of Dams
Dam failure can be defined as the sudden loss of ability to retain water, as a result of faults or damages affecting any of various parts of a dam .
There are various reasons which may lead to dam failure. These include foundation defects, natural hazards, over-topping or excessive water flow, and general mismanagement or neglect.
Dam failure may occur in the form of leakages, erosion, deterioration, and structural collapse. The effects of these events are often severe, involving significant economic loss and infrastructural damage.
Because all dams have the potential of failure, this is a risk and a disadvantage. Measures to mitigate the risk of dam failure include effective maintenance and efficient construction.
3). Population Displacement
When dams are constructed and deployed, a portion of land is usually converted to a water catchment or reservoir area.
This implies that the land in question will be submerged underwater.
People who occupy such submerged land areas are forced to evacuate. Several millions of people are believed to have been displaced as a result of dam projects since the last century .
At the same time, dam construction may strip the migrants of their livelihood, especially in areas where subsistence agriculture is common.
An managerialist approach has been proposed to address issues of displacement caused by dams . This approach ensures that dam construction projects are well planned and managed through preliminary assessment and effective collaboration among all involved stakeholders.
4). Environmental Impact
At various stages of their lifecycle, dams can have negative impacts on the environment.
Because dams often occupy large expanses of land, deforestation may be necessary to provide such lands. It is also believed that dams produce emissions that contribute to unfavorable climatic conditions and cause deforestation .
Dams may also contribute to greenhouse gas emissions . This is because dams can restrict water and oxygen circulation in reservoirs and river basins, causing carbon dioxide and methane to accumulate in large quantities when processes like respiration and biodegradation occur in the aquatic ecosystem. These gases may be subsequently released into the atmosphere.
Environmental degradation may be caused by dams in the form of aquatic pollution and growth of harmful invasive species.
Dams may alter river sedimentation patterns in a negative way, thereby altering the ecological equilibrium of the area.
Groundwater levels may be lowered under the influence of dams, causing plant growth and environmental sustainability to be affected.
5). High Capital Cost as one of the Disadvantages of Dams
Dam construction is usually capital and time-intensive.
This means that the initial economic demands of dams are high. Such requirements affect the feasibility of dam construction and usage.
6). Maintenance Challenges
Maintenance and operation of dams can be demanding in some cases.
Unlike other disadvantages of dams, these challenges may occur under some conditions. For example, when dams are to be used for domestic water supply, careful maintenance is usually needed to ensure that the water is of suitable volume and quality.
Also, consistent efforts are often needed to control the flow direction of water in dam systems. These measures may be time and money consuming, and usually require the services of experienced personnel.
7). Potential Conflict as one of the Advantages of Dams
In areas where drought risk is significant or water is in high demand, potential conflict is one of the major disadvantages of dams.
Such conflicts are likely to arise where the benefits of the dam are enjoyed predominantly by a given group or geographical area. Because water flow is controlled by dams, there may be disagreements regarding the choice of flow direction and water supply.
Advantages of dams are;
- Flood Control
- Pollution Control
- Hydroelectricity Generation
- Water Conservation
- Recreational Use as one of the Advantages of Dams
- Navigation Optimization
- Sustainable Water Supply as one of the Advantages of Dams
- Job Creation as one of the Advantages of Dams
- Dams may Serve as Tourist Attraction Sites
- Agriculture and Food Production
Disadvantages of dams are;
- Ecologic Disruption
- Potential Failure
- Population Displacement
- Environmental Impact
- High Capital Cost
- Maintenance Challenges
- Potential Conflict
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