Irrigation is the man-made supply of water to the land to encourage vegetation. It is a substitute for inadequate or erratic rainfall and is extremely essential for arid regions where there are no rivers and also in humid regions to improve crop output. In Pakistan, 75% of the agricultural land is under irrigation. Three major water sources in Pakistan are rain water, ground water and rivers.

Irrigation system is not something new. Since olden days, people had devised various methods to water their fields. Some traditional methods of irrigation are Persian Wheel, Charsa and Shaduf. Karez is another traditional irrigation system practiced in Baluchistan only. Karez is a horizontal canal located mainly on the foot hills and it brings the under ground water to the surface. Modern advancements in the irrigation system are the perennial canals and tube wells.
Pakistan is basically a dry country with the River Indus and its tributaries being the main source of water supply. Dams both large and small and barrages have been built on the Indus and its tributaries. Large dams such as Tarbela Dam and Mangla Dam are multipurpose plans which not only store water, irrigate lands but also generate hydro electricity. Small dams like Khanpur Dam, Rawal Dam and Hub Dam supply water for agriculture, industrial and domestic purpose and act as a reservoir as well. A hilly terrain is required to build a dam. Barrages on the other hand are built on flat places they also supply water for irrigation purpose and industrial and domestic use. Some barrages are Sukkur Barrage, Guddu Barrage, Kotri Barrage, and Chashma Barrage.

Canals are taken out from rivers, dams and barrages. Pakistan has one of the largest canal irrigation systems in the world. The Inundation canals are taken from rivers and they receive water only when the water level in the rivers is high such as during floods. The perennial canals are taken from dams and barrages and supply water to the fields through out the year. In Pakistan there are 3 large dams, 85 small dams, 19 barrages, 12 inter link canals, 45 canals and 0.7 million tube wells to meet the commercial, domestic and irrigational needs of the country.

Hydro-electric power is the production of power through the use of water. When water is made to fall using the gravitational pull of the earth, there arises a power which can be used for generating electricity. This is a concept which is fast picking up pace in Pakistan because of the acute shortage of regular methods of generating electricity. But there are a myriad advantages and disadvantages of hydro-electric power.

The advantages include the constant production of electricity using this method, the easy stoppage and remittance of electricity for times of high demand of power, the usage of lake water for irrigation purposes, and finally the electricity when in use does not emit greenhouse gases. Pakistan has been able to satisfy most of these requisites which has helped in satisfying its electricity requirements to some level.

Some of the primary disadvantages include the high cost of constructing dams, the eminent flooding of natural land and destruction of property, forcible movement of people from these areas, and the possibility of geological damage when the dams are constructed. Pakistan has kept a close eye on the advantages and disadvantages of hydro-electric power and has been trying to find out methods to reduce the latter.

There are basically 5 advantages of using hydro-electric power which apply for any nation. These I will mention weigh more for the nation of Pakistan because it is a developing country and it needs more reserves of electricity not available on a regular basis from any other source.

1. The primary advantage lies in its independence on the price of uranium, oil, and other types of fuel. This results in saving a lot of cash for allocation to other purposes.

2. The second advantage of hydro-electric power is the minimal amount of pollutants produced by it. Hydro-electric power gives out less or no wastage as byproduct.

3. Thirdly, it helps Pakistan cut down on the number of employees appointed for this function. A minimal staff will take care of a hydro-electric plant.

4. Fourthly, the size of the plant does not have to be the standard one. It can be customized to the size of the river or stream whose water is going to supplement the process.

5. Finally, another advantage of this process is the renewal factor which comes along with hydro-power into the country.