4.4.2 Perennial water

Growth of crop is highly affected by the amount of water and changes in temperature; according to an estimate, the increase in temperature by 0.5–2.5°C the agriculture productivity of the crop will decline by 8–10%, and this is estimated to be the case by year 2040 [40]. The crop growth simulation model showed that the length of growing season of major crops, i.e. wheat and rice, will decrease which will result in the decrease in yield of crop. Also the climate change projection provided by the Intergovernmental Panel on Climate Change (IPCC) states that the productivity of agriculture crop in Asia is bound to decline due to heat stress and

Irrigation - Water Productivity and Operation, Sustainability and Climate Change

Water right is the legal permission to use the water, or water laws and rights pertain to the water use by water user from different water sources, i.e. canal, floods, tube well, etc. The main aim of the water rights is to avoid the conflicts on water usage and its equal distribution, avoid the wastage, etc. Under spate irrigation there are different rules for flood water and perennial water. As the flood water has huge quantity of water, so usually distribution in quantitative term is difficult, but in the case of perennial irrigation, the distribution is quantitative. Prior to mechanical intervention, the rules in spate irrigation were strictly followed, and the

The torrential flood received in the plains is unpredictable both in time and magnitude. To effectively use the flood for agriculture and minimize the conflicts amongst the spate communities, certain rules were devised. The documented rules of water distribution are locally known as the Kuliyat and Riwajat-e-abpashi (formulae and customs for irrigation). The spate irrigation of D. I. Khan and D. G. Khan was first documented by the British Revenue administration in 1905 in the form of Riwajat and Kulyat-e-Abpashi [41]. These rules are still being followed. These rules follow the head-to-tail rule which is locally called as the saroba and paina. The earthen dams are built in the main riverine and used for diverting water. The upstream area irrigates their land first, and when the whole field is being irrigated, the earthen dam is breached. Kuliyat and Riwajat mainly emphasize on the follow-

The water rights rules in the spate systems of Dera Ismail Khan and Dera Ghazi Khan under the Sulaiman range in Pakistan were prepared by the revenue period during the British colonial period. The major work was done by Mr. HN Bolton during his tenure as deputy commissioner in 1908. This system was considered as an important source of tax; therefore the Revenue Administration had interest in the system. Also the water distribution right provided an opportunity to resolve the conflicts and disputes amongst the people [28]. The rules were enforced by the Rod Kohi department. The Kulyat Rodwar has these rules written in a register having

the floods and drought tend to increase.

government supervision was also firm.

ing main points as discussed by [41]:

1. When to breach the bunds (check dams)

3. Rights for second and third irrigations

2. The sequence of receiving water in the canal and field

4.Amount of water a farmer can store in the field

4.4 Water rights

4.4.1 Flood water

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Perennial water is another source of water in the spate irrigation. This water is locally called as Kala Pani; it is received throughout the year in the riverine through the streams. Like the land there is ownership for irrigation water. At watershed level the water is distributed amongst the different tribes living there. If we consider the example of Chodhwan Zam (watershed), the largest watershed in Dera Ismail Khan District, the perennial water is distributed between the Babar and Mina Khel tribes as 7:5. These are distributed through a unit locally called Boli. There are 10.5 Boli in the share of Babar tribes, which is again distributed as 1 for orchards, 1.5 for drinking and 8 for raising crops. Each boli is divided amongst the Babar subtribe or sub-cast. These casts are Musazai, Mardanzai, Badanzai, Shakarzai, Ahmad Khel, Ibrahimzai, Safarzai and Mangalzai. Each has single Boli. Each Boli is again divided into 18–20 wails, and in each wail there are 16 churukas. To make it understandable, 1 churuka means irrigation for 45 minutes depending on the amount of water. The water rights for the perennial water are different than flood water. The water in perennial system flows throughout the year. There are a number of crops that can be grown on perennial water. The perennial water may be used for irrigation on any land depending on its availability. Usually they are grown in the areas where they do not have the flood water rights. The tenure system in the perennial irrigating land is usually 7:5 for the land and water owner and the tenant.

Climatic sway has greatly influenced the perennial water as there is less rain during some of the years which may result in less water for recharging of streams and less water for perennial. Also during the flood season, the perennial water which mixes into the flood water as the riverine for both the flood and perennial water is the same. Also the farmers in spate are turning towards digging of tube wells, and some of them have been artesian well. Due to the extensive use of these

tube wells, there are chances of drying up of streams which may lead to declining of

Spate Irrigation: Impact of Climate Change with Specific Reference to Pakistan

The flows of spate have been utilized for irrigation for centuries, but to avoid losses and wastage of water, a huge storage dam has been constructed on one of the watersheds. Gomal Zam is the largest zam amongst the five with greater catchment area and greater command area. The Gomal Zam irrigated 24 villages of Tank and 60 villages of Dera Ismail Khan (Table 5). The Government of Pakistan has initiated construction of dam on the watershed in 2002. The dam is named after the name of watershed Gomal Zam Dam. The dam was completed in 2013. The storage capacity of the dam is 1.140 MAF. The dam provides as source of irrigation and operates under a well-controlled system. The command area under the dam is 65,200 ha. The discharge of water has enhanced the efficiency of water and reduced the threats of floods and drought in the command areas. It will also produce 17.4 MW electricity as Pakistan is also facing the energy crisis. The climate of the area is subtropical, hot in summer and cold in winter. The crops grown before the construction of dam were wheat, gram, sorghum and millet. Now there is a potential of growing other crops as cash, cereal and sugar crops. The perennial availability of water has changed cropping pattern, and also the land which was previously kept

Gomal Zam dam is the first intervention in which the spate water has been stored in a huge dam, because the heavy flood in the spate irrigation was difficult to control and used to cause much of the damage to the property and also the lives. Due to greater mass and velocity of the floods, the kinetic energy becomes greater and the damage it causes is also massive. The dam has positive impact on the economics and agriculture of the area which are noteworthy. After shifting from spate to canal irrigation, the mindset needs to be changed. There are several projects which are running to equip the farmers of the command area with improved techniques such as laser leveling, extension activities, etc. Also the area below the command area which had the water right in the spate irrigation has become

deprived of the water resource on one hand, and also the ecology of the area has also

The spate-irrigated area focused in this chapter has the diversified physiography, with mountains on the west and River Indus on the east. The area is distinguished in terms of climate, land and water resources. The climate varies from very hot summer temperature ranging from 35 to 45°C to cold winter with temperature of 5–15°C. The district was previously under the spate irrigation and has the landform of piedmont, with vast land. After the construction of gravity canal from the Indus River known as Chashma Right Bank canal, more than half of the area become irrigated in the downstream. The western part still remains part of the spate irrigation. With the recent development, some of the influential landowners of spate have installed tube wells to irrigate the lands. But studying the hydrology of the area, it is evident that the groundwater in the spate-irrigated area is brackish. Most of the tube wells in the area are deep installation at 400–500 ft. The construction of Gomal Zam dam has also developed the area in terms of perennial irrigation.

perennial water flow.

4.5 Construction of dams

DOI: http://dx.doi.org/10.5772/intechopen.85889

– fallow – was used for cultivation [42].

changed, as the area now has become rainfed.

5. Discussion and conclusion

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#### Table 5. Villages under Gomal Zam dam command area.

tube wells, there are chances of drying up of streams which may lead to declining of perennial water flow.
