WATERLOGGING
Soil that is saturated with water is called waterlogged soil. Water that fills the earth is called rain. The content of groundwater will be very high in wet soil. In this way the land will be filled with water.
Causes of water logging
There is the best drainage system in Pakistan. It has 40790 miles. But they have some drawbacks. There are some problems with water:
- Construction of dams and barrages: There are some of the largest dam barrage in Pakistan like Terbela Dam and Sukkur barrage. The bed of these dams it made up of mud. Their walls are not made up of concrete. Thus water can easily seep through its best and walls. It causes waterlogging in nearby areas
- Defective canal system: The canals in Pakistan are not lined during construction Similarly, hardpan of canal beds is broken during digging of canals. Therefore, seepage of water takes place. It is estimated that 45-50% of the water is lost from different canals and land. It raises the water table of soil. Thus it causes waterlogging over large areas.
- Unscientific Irrigation: Our farmers have adopted unscientific irrigation systems. Most of the water is collected in the ditches in the field. It causes water logging.
- Lack of drainage system: Monsoon rain and frequent floods form small lakes and ponds also cause water logging. There is a lack of drainage system. Thus this accumulated water cannot be drained out. This water gradually seeped downwards and reached the water table. Thus it raises it ground water surface.
- Lower slope angle: Soil surface of plains of Pakistan is Oat. Its slop angle is much lower. Thus flow of water in streams, canals and rivers is much slow. Therefore, water has a lot of time to seep into the soil. It increases the water table and causes water logging.
- Rainfall: Pakistan comes within the heavy monsoon rainfall area. Therefore, a lot of rain fall occurs in northern and coastal areas of Pakistan. This rain fall causes heavy flooding in southern areas of Pakistan. The land of Pakistan is porous. Therefore, water seep into the soil. It raises water table and cause waterlogging.
- Barrier to flow of water: Roads and bridges in Pakistan are constructed without proper planning. These are constructed without proper drains for flood and rain water. Therefore, they become barrier to flow of flooded water. Thus water spread to nearly areas and seep into the soil. It causes waterlogging.
Effects of water logging
There are following effects of waterlogging and salinity:
- Effect on soil structure: Water logging and salinity destroy the soil structure. Different layers of the soil are badly affected.
- Decreasing oxygen in soil: The soil is saturated with water. Therefore, the oxygen content of the soil is decreased. Thus oxygen is not available to the roots of the plants for respiration. So the plants die.
- Promoting anaerobic conditions: It causes anaerobic condition in the soil. Thus anaerobic microorganisms are produced in it. The anaerobic microorganisms produce methane (CHA) and hydrogen sulphide (HS). These gases produce foul smell. They make the soil unfit for other beneficial soil organisms.
- Deficiency of nitrogen in soil: The number of aerobic organisms is reduced in waterlogged soil. It reduces the decomposition of the organic matter of the soil. It causes deficiency of nitrogen in the waterlogged soil.
5 Leaching of soluble salts: It causes deflocculation of soil. Water causes leaching of increased. It the soluble salts. Thus the upper soil layer is without nutrients.
- Effect in soil pH: The soil pH become high and osmotic pressure is badly affects the plants and other soil organisms
- Spreading of diseases: Waterlogging is also injurious to public health. Mosquitoes and flies breed in waterlogged area. They spread malaria and other water borne diseases.
- Effects on buildings: The farmers cannot construct their houses in waterlogged areas. The houses sink in the ground in these areas. Waterlogging also destroying the houses in villages, towns and cities. Cities of Peshawar and Faisalabad are badly affected by these problems.
Effects of water logging in Pakistan
Most of the plants cannot grow in waterlogged and saline conditions. Therefore, most of land of Pakistan has become barren. Water logging is destroying our irrigated lands rapidly. It can be compared with the cancer in the human body. We are unable to achieve self-sufficiency in food due to waterlogging. Most fertile and valuable lands of the country have wasted. The farmers are facing innumerable problems. It is badly affecting our economy, Waterlogging is affecting our lands at the rate of an acre a minute. According to a rough estimate it is affecting our lands at the rate of 1 lakh acre every year. There are total forty million acres of our irrigated areas. 5 million acres are severely affected by salinity. 12 million acres are suffering from salinity patches. 15 million acres are poorly drained or waterlogged.
Types of waterlogging
Waterlogging can occur in various forms, depending on the specific circumstances and causes. Here are different types of waterlogging based on their causes and characteristics:
- Surface Waterlogging: This type occurs when excessive surface water accumulates due to heavy rainfall, inadequate drainage systems, or flooding. It leads to temporary or localized flooding in low-lying areas.
- Subsurface Waterlogging: Subsurface waterlogging happens when the water table rises to the point where it saturates the root zone of plants. This prevents plant roots from accessing oxygen and nutrients. It can result from high groundwater levels or poor soil drainage.
- Irrigation-Induced Waterlogging: Excessive irrigation, either from overwatering or inefficient irrigation methods, can cause waterlogging. This is common in agricultural settings when the soil cannot absorb the applied water quickly enough.
- Urban Waterlogging: Urban areas often face waterlogging due to impermeable surfaces like roads and buildings, which prevent rainwater from infiltrating the soil. Inadequate stormwater drainage systems exacerbate this problem, leading to flooding during heavy rainfall.
- Saline Waterlogging: Saline waterlogging occurs when there is an accumulation of salt in the soil, typically as a result of high groundwater levels in arid or semi-arid regions. The high salt concentration makes the soil unsuitable for most plants.
- Alkaline Waterlogging: In some cases, rising groundwater can bring alkaline (high pH) water to the surface, causing alkaline waterlogging. This elevated pH can negatively impact plant growth.
- Acidic Waterlogging: Acidic waterlogging is rare but can happen when acidic groundwater rises, leading to low pH levels in the soil. This acidity can harm plants and alter soil chemistry.
8.Seasonal Waterlogging. Some regions experience waterlogging only during specific seasons, such as the rainy season. Seasonal waterlogging can impact agriculture and land use planning.
- Tidal Waterlogging. Coastal areas are susceptible to tidal waterlogging, where high tides inundate low-lying areas. This can affect both urban and agricultural land along the coast.
- Riverine Waterlogging. Riverine waterlogging occurs in proximity to riverbanks when periodic river flooding inundates the adjacent land. This type of waterlogging affects agriculture and settlements near rivers.
- Artificial or Reservoir-Induced Waterlogging. The construction of reservoirs or dams can lead to waterlogging in upstream areas due to changes in the water table caused by the impoundment of water.
- Mining-Induced Waterlogging: Mining operations can alter the hydrogeological conditions, leading to waterlogging in nearby areas. Abandoned mines may also fill with water over time, causing localized waterlogging.
The type and severity of waterlogging depend on various factors, including climate, soil properties, topography, and human activities. Effective management strategies, such as proper drainage, sustainable land use planning, and water conservation practices, are essential to address and prevent waterlogging issues.
Reclamation of soil from waterlogging
Following measures usually can be taken to check and reclaim the waterlogged soil.
- Lining of canals: Canals should be lined with concrete. It will prevent the seepage of water. Process of lining of canal has been already launched in waterlogged areas of Pakistan. A large number of canals have been already lined.
- Installation of tube wells: Installation of tube well is the most effective method of reclaiming the lands. The tube wells draw water from the land. They lower the water table. Tube wells are very beneficial in the localities where subsoil water is suitable for irrigation. It gives dual benefit. Firstly water level is lowered and secondly crops can be irrigated by the water. In some localities, tube well water is brackish. This water can be mixed with canal water for irrigation purposes.
- Drainage system: Effective drainage system prevents the rise of the water table. These drains carry away saline water. Thus new drainage canals should be constructed and the older ones should be made efficient. Bed rocks should be broken for gravitational drainage.
- Scientific irrigation: Irrigation should be done on scientific lines. Research should be carried out to determine the consumptive use of water by different crops. It can prevent loss of water through percolation to the deeper layers. The leveling of the fields should be done with laser land leveler. It makes the smooth flow of water thorough the agricultural fields.
- Use of manures: Farm manure should be used at the rate of 10-20 tons per acre. This manure is composed garbage from the towns. It improves the soil structure porosity and nutrition. Gypsum is also beneficial for improving the soil structure.
- Plantation of trees: Trees should be planted along both sides of the canals up to 500 feet. They make the wall of canal strong. It reduces the seepage of water from the canal bank. Secondly, this loss the seeped water by transpiration.
- Planting waterlogged resistant corps: Rice, sugarcane, and barseen can be grown in waterlogged soils. These corps can be easily grown in waterlogged soil.
Reclamation of soil in Pakistan
WAPDA has started different reclamation projects under the SCARP (Salinity Controland Reclamation Project). It is estimated that about 7 to 8 million acres of land has beenreclaimed throughout Pakistan. In these localities water table has gone down andwaterlogging has been eliminated. Crop acreage and crop yields have increased in these areas.
Conclusion
In conclusion, waterlogging is a significant environmental issue characterized by the excessive accumulation of water in the soil or on the surface, which hinders plant growth, disrupts ecosystems, and poses various challenges to human activities. It can manifest in different forms, such as surface waterlogging, subsurface waterlogging, irrigation-induced waterlogging, and more, each with its unique causes and impacts.
Waterlogging is influenced by factors like climate, soil type, topography, and human activities such as irrigation, urbanization, and land use practices. It can lead to adverse consequences, including reduced agricultural productivity, damage to infrastructure, urban flooding, and ecological imbalances.
Effective mitigation and prevention strategies for waterlogging involve improved drainage systems, sustainable land management practices, judicious water resource management, and the development of resilient infrastructure. As climate change and urbanization continue to affect water patterns, addressing waterlogging remains crucial for maintaining environmental sustainability and ensuring the well-being of communities worldwide.
Q/A
Certainly, here are some questions and answers related to waterlogging:
Q1: What is waterlogging?
A1: Waterlogging refers to the condition in which soil becomes saturated with excess water, hindering the growth of plants and causing various environmental and agricultural issues.
Q2:What are the common causes of waterlogging in urban areas?
A2: Common causes of waterlogging in urban areas include poor stormwater drainage systems, impermeable surfaces, heavy rainfall, and inadequate urban planning.
Q3: How can waterlogging affect agriculture?
A3:Waterlogging can reduce crop yields by depriving plant roots of oxygen and causing soil degradation. It can also lead to the loss of crops due to root damage and diseases.
Q4: What are some methods for preventing waterlogging in agriculture?
A4: Methods to prevent waterlogging in agriculture include improving soil drainage, adopting appropriate irrigation practices, and choosing crops that are tolerant to wet conditions.
Q5: What is the difference between surface waterlogging and subsurface waterlogging?
A5: Surface waterlogging occurs when water accumulates on the soil’s surface, while subsurface waterlogging happens when the water table rises to saturate the root zone of plants.
Q6:How does waterlogging impact urban infrastructure?
A6: Waterlogging can damage roads, buildings, and other infrastructure, leading to costly repairs and posing safety hazards for residents.
Q7: What is saline waterlogging, and where is it commonly found?
.A7: Saline waterlogging occurs when the soil becomes saturated with water containing high levels of salts. It is often found in arid or semi-arid regions with high groundwater salinity.
Q8: How can climate change influence the occurrence of waterlogging?
A8: Climate change can lead to more frequent and intense rainfall events, potentially increasing the likelihood of waterlogging in affected areas.
Q9. What are some sustainable solutions for mitigating waterlogging in urban areas?
A9: Sustainable solutions for urban waterlogging include green infrastructure (such as permeable pavements and green roofs), improved stormwater management, and urban planning that considers water drainage.
Q10: Why is proper land use planning essential in preventing waterlogging?
A10: Proper land use planning helps ensure that urban and agricultural areas are developed in ways that minimize waterlogging risks. This includes avoiding construction in flood-prone areas and implementing effective drainage systems.
