Definition causes effects and differences between flood and drought
Flood is the most frequent type of natural calamity that may be caused by heavy rainfall or some other factors. It can have various disastrous impacts. The flood may lead to a scarcity of clean drinking water. Drought is the opposite of flood; it is also a natural calamity.
Flood
A flood is usually an excess of water that drowns usually dry land. Usually, there are five types of floods.
River flood occurs when the water level of the sea rises above the top of the banks of the river.
A coastal flood is an inundation of dry land areas along the coast of seawater.
Strome surge is an abnormal increase in the water level in coastal areas.
Inland flooding is flooding that does not occur in coastal areas or occurs inland.
A Flash flood is a flood that begins after 3-6 hours of heavy rain.
Causes of Flood
There may be many causes of floods. The main causes are given below.
Ice and Snow Melt - Some mountains have ice caps on them. When this icecap melts in the summer season, it results in huge releases of water into the places that are usually dry.
Lack of Vegetation - vegetation can interrupt the flow of water. If there will be no vegetation, there will be nothing to slow down the flow of water.
Broken Dams - When heavy rain comes, the water level increases in the dams and ageing dams can break and can unleash overflows of water in the household.
Heavy Rains - Whenever there is heavy rain and the drainage system is not proper, it may result in a flood or flood-like conditions.
Climate Change - Climate changes occur mainly due to human practices. Due to deforestation, there will be more carbon dioxide in the atmosphere, which may lead to the melting of glaciers.
Emission of Greenhouse Gases - The burning of fossil fuels can lead to the emission of greenhouse gases which increase the atmospheric temperature and hence there will be melting of the glaciers.
Effects of Flood
A flood can harm wildlife.
Flood carries contamination and can cause disease.
A flood can trigger breeding events and migration.
There may be a loss of goods and life in the flood.
A flood can cause soil erosion.
Drought
Drought is defined as the prolonged period of dryness in the natural climate cycle.
Causes of Drought
There are natural causes as well as human causes of drought.
Human Causes Include the Following:
Overpopulation if too many people living in any particular area and using too much water can lead to scarcity of water.
Over cultivation of planting too many plants can use too much water.
Deforestation of plant roots can hold some amount of water, but cutting down them may lead to the condition of drought.
Natural Causes Include the Following:
Less rainfall for weeks and years may be a major cause of the drought.
Effects of Drought
Drought can have various serious impacts on health, economy, and politics.
It may result in hunger.
Due to lack of water, there will not be enough food crops. Same conditions with the poultry and feed livestock.
Wildfire: Due to the drought, there will be a lack of moisture in the soil and environment and if there would be a hotter environment, it may lead to a fire in the forests.
The wildlife would be damaged due to a lack of enough water.
Water is essential to survive, if there would be a lack of drinking water, people may have various health-related issues such as dehydration.
Conclusion
Flood and drought both are natural calamities. We can prevent these calamities or can reduce the impact of floods and drought by following certain measures. These calamities were majorly due to natural reasons but nowadays we can see an increase in flood and drought due to human interference. Humans are over-exploiting natural resources such as deforestation which causes an imbalance in rain.
FAQs on Flood and Drought in Environmental Chemistry
1. What is a flood in environmental science?
A flood is the overflow of excess water onto normally dry land due to heavy rainfall, river overflow, storm surges, or dam failure. In environmental science and hydrology, floods occur when the water cycle delivers more water than soil infiltration and drainage systems can handle.
- Caused by intense precipitation, rapid snowmelt, or cyclones
- Leads to soil erosion, water contamination, and infrastructure damage
- Often increases turbidity and alters the chemical composition of surface water
2. What is a drought and how does it occur?
A drought is a prolonged period of below-average rainfall that results in water scarcity and reduced soil moisture. It occurs when evaporation and water demand exceed precipitation over weeks, months, or years.
- Meteorological drought: low rainfall
- Agricultural drought: low soil moisture affecting crops
- Hydrological drought: reduced river, lake, and groundwater levels
3. What is the difference between flood and drought?
The main difference between a flood and a drought is that a flood involves excess water, while a drought involves severe water shortage.
- Flood: high precipitation, surface runoff, and water overflow
- Drought: low precipitation, high evaporation, and depleted water reserves
- Floods cause waterlogging and contamination; droughts cause dehydration and crop failure
4. How are floods and droughts related to the water cycle?
Floods and droughts are extreme imbalances in the hydrological (water) cycle. The water cycle involves evaporation, condensation, precipitation, infiltration, and runoff of H2O.
- Excess precipitation and runoff → floods
- Reduced precipitation and high evaporation → droughts
- Climate change alters evaporation rates and rainfall patterns, increasing extremes
5. How does climate change affect floods and droughts?
Climate change increases the frequency and intensity of both floods and droughts by altering temperature and precipitation patterns. Rising temperatures increase evaporation, while warmer air holds more water vapor, leading to intense rainfall events.
- More extreme storms → flash floods
- Longer dry spells → severe drought
- Increased atmospheric CO2 enhances global warming
6. What are the chemical impacts of floods on water quality?
Floods degrade water quality by increasing suspended solids, nutrients, and pollutants in rivers and lakes. Runoff carries fertilizers, sewage, and industrial waste into water bodies.
- Rise in nitrates (NO3-) and phosphates (PO43-)
- Higher biological oxygen demand (BOD)
- Possible contamination with heavy metals like Pb and Hg
7. How does drought affect soil chemistry?
Drought alters soil chemistry by increasing salinity and reducing nutrient availability. When water evaporates, dissolved salts remain in the soil.
- Accumulation of salts like NaCl and CaSO4
- Reduced microbial activity
- Lower nitrogen fixation and organic matter decomposition
8. What are the types of floods?
The main types of floods are flash floods, river floods, coastal floods, and urban floods. Each type differs based on cause and location.
- Flash floods: sudden, intense rainfall
- River floods: overflow from rivers due to prolonged rain
- Coastal floods: storm surges and cyclones
- Urban floods: poor drainage and impervious surfaces
9. What are the main causes of drought?
The main causes of drought include low rainfall, high temperatures, deforestation, and excessive water use. These factors reduce available freshwater resources.
- Reduced precipitation over long periods
- Increased evaporation due to heat
- Over-extraction of groundwater
- Loss of vegetation cover
10. How can floods and droughts be managed or prevented?
Floods and droughts can be managed through sustainable water management, infrastructure planning, and environmental conservation. Effective strategies reduce risk and environmental damage.
- Rainwater harvesting and groundwater recharge
- Construction of dams and levees for flood control
- Efficient irrigation systems during drought
- Afforestation and wetland restoration
