Tag: Irrigation

Introduction

A dam is a man-made obstruction built across a river or underground stream to restrict the flow of water. This results in the creation of artificial lakes or reservoirs. Then, this has other uses. such as irrigation, domestic purposes, flood control, commercial purposes, aquaculture, electricity production, etc. They used bricks, clay, concrete, cement, iron riding, etc. to build their construction. Even though it provides a lot of benefits, there are some drawbacks as well. The environment of the river will be impacted when more dams are built over it. due to the abundance of aquatic life in the river. There is therefore a pressing need for a dam alternative.

Advantages of Dams

A dam has several advantages, ranging from economic to social advantages. The following is a list of benefit of a dam.

• Water storage: It can serve as a sizable water reserve that can be used for domestic, commercial, and agricultural purposes. Additionally, it has the capacity to accept extra surface water.
• Recreation: Dam’s are a point of public attraction as many leisure activities like boating, camping, swimming, etc. can be done in this area.
• Irrigation:The dam is a significant source of water for irrigation.
• Debris control: The dam has improved environmental protection by reducing the amount of trash thrown into rivers.
• Electricity production: Hydropower is a crucial source of electricity because it doesn’t produce any chemical waste. The majority of the nation’s primary source of electricity is generated from water.

Disadvantages of Dams

Dams are constructed to generate additional electricity for use by people. However, the bulk of these dams are unable to make a significant impact on the generation of power for human needs. Instead, it has certain negative repercussions on both the ecology and people as a whole. Some of them are mentioned below-

• Dam construction has an negative impact on the aquatic life that exists in the water.
• There is lots of water wastage during the process of dam construction.
• It has affected the people who live nearby as a sizable portion of land has been buried to serve as a water reservoir.
• Due to dam construction biodiversity in the water has reduced.
• There is an increased sediment accumulation
• Soil erosion has occurred in places nearby to the dams.
• There is a danger of catastrophe because by chance if the dam structure breaks it will threaten the lives of  thousands of people,
• Overflow of water in the dam may happen if more water reaches the surface by rain which might lead to flooding in the nearby areas.

Alternative solutions to Dams

Dams have a number of drawbacks since they are not the ideal solution for meeting human requirements. Therefore, finding a dam replacement is essential. Some of the alternative solutions to dams are given below-

• Concentrating on alternative energy sources-The construction of dams is a result of the rise in electricity demand; therefore, finding an effective source of energy production will lessen the danger posed by dams. Some common alternative energy sources ares nuclear power plants, thermal power plants, solar electricity, wind power, etc.
• Reuse of water: The dam provides water for numerous uses that. Therefore, locating new alternate water sources can also help to lower the number of dams. For instance, sewage water can be recycled and used again for a variety of various purposes, including industrial and agricultural ones.
• Managing flood: By reducing the water runoff we can control the flood of many rivers. Since dams play a prominent role in the prevention of floods in rivers.
• Concentrate more on the current dams: Only small a fraction of dams are used effectively. Hence,prior to building a new dam, one must pay attention to the older dams and make the best use of them.As a result, fewer dams may be constructed to bridge rivers.
• Groundwater recharge: Increased water deposition from surface water to groundwater is known as groundwater recharge. This process increases the water content below the ground level which can be used for various other purposes.

Summary

Water is a priceless resource that is essential to maintaining human life. It may be used for everything from generating electricity to drinking puropses. Consequently, a reliable water source is always going to be required. A dam is a man-made structure designed to preseve water. Nevertheless, while there are numerous benefits of dams, there are also some drawbacks. Being a man-made construction, it has a severe impact on the ecosystem around us. Therefore, a water  resource other than the dam is desperately needed. Alternative methods of dams include replenishing the groundwater table, locating alternate energy sources, etc. If appropriate measures are not taken into consideration, we could face a number of issues. And hence for this purpose new technologies must be implemented..

Frequently Asked Questions

1. Which of the dams on Earth is the oldest?
Ans: The dam Jawa, which is situated in Jordan, is the oldest dam still in use today. There are still some of this dam’s remains.

2. How long do dams last?
Ans: A dam’s lifespan is estimated to be 50 years on average. In this lifespan, it can function successfully. There are also other dams that date back far more.

3. Can a dam contaminate water?
Ans: Since dams stop the flow of water, they can accelerate the growth of any existing microbes in the water, which can render the water hazardous. The number of diseases spurred on by water pollution has been rising daily. Additionally, metallic components can also accumulate in such stagnant waters which can further harms marine life.

Introduction

A dam is a physical structure that slows or restricts the flow of subsurface or surface water. Dams build reservoirs that serve multiple purposes, including flood control, irrigation, human consumption, industrial use, aquaculture, and navigability. Although they are more frequently erected on rivers, dams can be constructed anywhere. They may also be built on streams and estuaries.

What is a Dam?

A dam is a sizable, barrier-like structure that is erected across a body of flowing water. Water is held back and stored for later use because of construction. A reservoir is a term used to describe the vast amount of water storage created on the upstream side of a river when it is prevented from flowing by a barrier. Floodgates on dams can be opened or closed to allow only a small flow for human use.

During floods, gates also enable the release of extra water from the reservoir side. A surplus of water collects on the reservoir side of a river when it floods. To let surplus water out, the floodgates are slowly opened. Dams are primarily built for this reason.

For more help, you can Refer to lesson 16 – Water in Science Class 7. Checkout the video Lesson for a better understanding

Uses of Dams

• Irrigation: In recent years, irrigation for crops has primarily been provided by dams. Rainfall in tropical nations like India is only experienced for a portion of the year. However, agriculture is a year-round industry that uses water for growth, depending on the stage of growth. While others, like rice and sugarcane, require excessive amounts of water. Agriculture was made possible by irrigation, even in remote areas with low subterranean water levels.
• Electricity: The floodgates are opened, allowing the reservoir’s water which is already under high pressure to pass through the turbine that powers the generator. A turbine transforms the kinetic energy of water into mechanical energy, which is then transformed into electrical energy by a generator.
• Reservoirs are a great place for recreation. Many reservoirs provide the local people with camping, boating, and fishing facilities.

Advantages of Dams

• Hydroelectric power, which is produced by dams, is independent of all fossil fuels. As a result, hydroelectricity is a source of energy that is constantly replenishing and can be used. With a growing population comes a rising need for energy. One of the safest methods to address the energy situation is using hydroelectric electricity.
• A reservoir maintains a sizable water reserve that is mostly used to store fresh water that can be used later in times of water scarcity.
• You can irrigate with the reservoir water. Crop plants can be effectively watered across long distances. Food is produced on the irrigated farmlands. Demands for drinking water are alarmingly rising along with population growth.
• Floods are prevented by dams, which redirect water flow. Numerous lives are saved every time water is slowly released from reservoirs through floodgates, and property damage is also avoided. 
• A reservoir is a gathering place for many aquatic animals, including fish and turtles. When dams are built, a river that is already flowing becomes a lake. It becomes a lake environment when freshwater fish and turtle species seize the opportunity to multiply.

Disadvantages of Dams

• To create a sturdy basement and reservoir, large layers of dirt must be dug out during the dam’s construction. The earth’s topography is harmed by this. Because of this, earthquakes happen more frequently. However, effective engineering, design, and planning can stop such destruction. 
• Dams are substantial, concrete buildings. They are not built economically. 
• Dam construction necessitates a vast area. It is necessary to move the local farmers and residents to the area. Their social and economic lives are affected, and there are long-term repercussions.
• In addition to displacing people, the natural habitat is also greatly disturbed. Concerns about the flora impacted by dam construction are mostly focused on deforestation and the loss of agriculturally productive land. 
• Natural wildlife that lives in the dam region is also out of control and occasionally even poses a threat to its population. To maintain their populations, breeding grounds and nesting locations are crucial. When other factors perturb these areas, their population changes. 
• Bird species are disturbed, in addition to terrestrial and aquatic species. 
• Fish living in freshwaters are the primary food source for migratory birds that nest on riverbanks. 
• Migratory birds lose their feed and are prevented from reproducing as they do throughout the year due to the drastic shift in aquatic life caused by dam building.
• The groundwater table in the surrounding areas is decreased as a result of deepening the riverbed to create reservoirs. This has a significant negative influence on nearby, naturally occurring vegetation.

Summary

A dam is a physical obstruction that slows or restricts the flow of subsurface or surface water. Floodgates on dams can be opened or closed to allow only a small flow for human use. In recent years, irrigation for crops has primarily been provided by dams.  A reservoir maintains a sizable water reserve that is mostly used to store fresh water that can be used later in times of water scarcity. Dams are substantial, concrete buildings. They are not built economically.

Frequently Asked Questions 

1. Do Dams Last Forever?
Ans. A dam may be built in around ten years, and its lifespan is about one hundred years. Certain mechanical components, including motors and gates, need to be changed after a dam has been in place for 50 years. However, operational dams will undergo routine inspections. When necessary, all repairs and maintenance will be carried out right away.

2. Can we Rely Solely on Hydroelectricity to Provide our Electricity?
Ans. A renewable energy source is a hydroelectricity. Since the dam-related operation does not disrupt the water cycle, the claim that water will not run out is valid. The problem is that rivers and streams are the only sources of flowing water that dams may use. Hydroelectric power cannot be the only source of sustainably produced energy.

3. What Connection does a Dam have to Greenhouse Gases?
Ans. Large expanses of vegetation are flooded when a dam is built, submerging numerous trees. Low oxygen levels can be found near the bottom of stagnant waters in reservoirs. The reservoir’s lower layers, which are abundant in biomass, effectively release methane into the atmosphere as it breaks down.

4. What Advantages do Dams Offer to Farmers?
Ans. Large amounts of water are stored in reservoirs where they can be irrigated for use in agriculture. Croplands can also be effectively irrigated in semiarid areas far from the riverbed. Rainfall is not necessary for farmers to be able to cultivate.

Introduction

Agriculture is the practice of raising animals and cultivating crops. To meet the growing need of the population, the seed is crucial in the development of palatable foods. It is a fertilized ovule that germinates to give rise to new plants. The crucial phase in agriculture is choosing good quality seeds because they can reduce replanting, improve uniformity, and encourage the early growth of crops. Proper agricultural practices increase the yield and quality of crops produced.

Selection of Seeds

In general, seed quality affects plant development. Selecting effective seeds, and seed selection can boost agricultural yield. Getting seeds from healthy plants is crucial for agriculture since many different plant diseases can be spread through them. Spreading out chosen seeds over the initially prepared soil is the act of sowing. When choosing seeds for sowing, the following characteristics of the seeds are essential:

• Infections shouldn’t be present in the seeds. 
• They ought to have a strong ability to germinate. 
• A specific seed shouldn’t be combined with weeds or other seeds. 
• They ought to produce the desired amount of crops. 
• Avoid using seeds that have been damaged or crushed. 
• They ought to be immune to illness. 
• They ought to be able to endure challenging circumstances.

Steps to Ensure Proper Growth of Seeds

Agricultural practices are a set of rules used in the agricultural sector to make farming easier and produce better agricultural goods.

Preparation of Proper Soil

The agricultural area must be prepared for crop production through soil preparation. For seeds to germinate and help with efficient agricultural cultivation, it is necessary. The process of preparing soil involves these three steps:

• Tilling/Ploughing: ploughing is the process of liquifying and moving the soil to improve adequate aeration and bring the nutrient-rich soil to the surface of the land. It is done with a cultivator, hoe, or plough.
• Levelling: Because the earth is lumpy and irregularly dispersed, the levelling procedure distributes the soil evenly and levels it out. Additionally, it guards against soil erosion.
• Manuring: To grow and produce fruits and seeds, plants need the right nutrition. Applying manure to agricultural land is known as manuring. Manure is an organic material that has decomposed and is used to enrich the soil by delivering nutrients for crop growth.

Sowing of Seeds or Planting  

Sowing refers to the act of distributing or planting seeds. The right depth and quantity of water must be used while planting seeds. To achieve a desirable culture, the right seeding distance and interval are crucial. The following are some seeding techniques:

• Traditional method: For sowing, a funnel is employed that is filled with seeds that are travelling via pipes with sharp edges. The seeds are dispersed as the pipe’s edge penetrates the ground.
• Broadcasting: By distributing seeds throughout the ground, seeds are sown by the manual or mechanical method called broadcasting. However, owing to the uneven seed dissemination, this strategy is not advised for the growth of high-yielding crops.
• Dibbling: The act of “dibbling” involves evenly spacing the seeds in the seedbed before covering them with dirt. A long, pointed tool called a “dibbler” is used to make holes in the earth before sowing.
• Seed drill: Typically, tractors are utilized to assist in the sowing of seeds using a seed drill. The seeds can be sown at the proper depth and distance, and it is crucial to make sure the soil is covered after sowing.
• Transplantation: The seedlings are moved to the cultivable land after the seeds have initially been sown in a small garden. As a result, this procedure takes a long time.

Proper and Timely Irrigation

Agriculture requires proper irrigation since excessive watering can harm the soil by causing water logging, which hinders the soil’s ability to absorb nutrients and minerals. Because the farmer needs to supply enough water, successive irrigation necessitates breaks.

Supply of Proper Manure and Fertilizers

To provide the nutrients needed for plant growth, manure and fertilizers are added. Manure is made from decomposed animal and plant wastes, making it an environmentally benign substance that also improves soil fertility. Inorganic fertilizers like ammonium sulfate, ammonium phosphate, and NPK are produced commercially, and too much fertilizer can impair the soil’s ability to support plant growth.

Protection of Crops/Plants From Weeds

Unwanted plants, known as weeds, can harm farmed plants by growing near desirable ones. Crop yields are reduced, and pests and diseases use it as a host plant. These are eliminated by hand or using weed killers like naphthalene, acetic acid, etc.

Summary

The crucial phase in agriculture is choosing good quality seeds because they can reduce replanting, improve uniformity, and encourage the early growth of crops. Selecting effective seeds, and seed selection can boost agricultural yield. Agricultural practices are a set of rules used in the agricultural sector to make farming easier and produce better agricultural goods. The right depth and quantity of water must be used while planting seeds. 

Frequently Asked Questions

1. What makes Manure and Fertilizer different from one Another?
Ans. Fertilizers like ammonium sulfate are inorganic, whereas manure is an organic chemical made from the breakdown of plant and animal waste.

2. Write a note on Agricultural Practices.
Ans. Agriculture practices are a collection of rules that make farming easier. It entails the following: preparing the soil, choosing the right seeds, sowing, applying manure, fertilizers, and weedicides, as well as ensuring correct watering, harvesting, and storing.

3. Define Winnowing and Threshing.
Ans. Winnowing is the technique of separating grains utilizing the wind, whereas threshing is the act of freeing harvested grains by hand-battering or mechanical means.

4. What role does Seed Selection Play in Agriculture?
Ans. For the development of new individual plants, seeds are necessary. The development of desirable crops that decrease replanting and increase crop production can be achieved by choosing high-quality seeds.