China
Africa
Explore chapters and articles related to this topic
Major hydraulic structures in the world
Published in Amithirigala Widhanelage Jayawardena, Fluid Mechanics, Hydraulics, Hydrology and Water Resources for Civil Engineers, 2021
Amithirigala Widhanelage Jayawardena
Major hydraulic structures can be broadly classified into canals, storm surge barriers and dams. Some major canals are used as modes of transportation whereas some are used for transferring water from places of abundance to places with shortage. Storm surge barriers are built to protect coastal regions from combinations of high tide, waves caused at times of extreme weather and fluvial flow from rivers. Dams are built to produce hydroelectricity, for flood protection and for irrigation and water supply. All major dams are multi-purpose since constructing a single purpose dam does not justify the huge capital expenditures involved.
Anthropogeomorphology of the Lower Deltaic West Bengal with Special Reference to the Hugli River System
Published in Balai Chandra Das, Sandipan Ghosh, Aznarul Islam, Suvendu Roy, Anthropogeomorphology of Bhagirathi-Hooghly River System in India, 2020
Nabendu Sekhar Kar, Sayantan Das, Sunando Bandyopadhyay
The LDWB is traversed by a number of canal networks. The earlier canals were excavated by the colonial rulers followed by constructions under post-independence large-scale river projects. The canals can be divided into two categories: the irrigation canals and the drainage canals.
Drought Management Planning Resources for Water Suppliers in Pakistan
Published in Saeid Eslamian, Faezeh Eslamian, Handbook of Drought and Water Scarcity, 2017
Saifullah Khan, Saeid Eslamian
The Indus Valley Civilization in Pakistan (from ca. 2600 BC) also had an early canal irrigation system. Large-scale agriculture was practiced and an extensive network of canals was used for the purpose of irrigation. Sophisticated irrigation and storage systems were developed, including the reservoirs built at Girnar in ca. 3000 BC [27]. Besides, some of the toys of the Indus Valley Civilization indicate that there was a proper system of water supply into different houses and places (Figure 25.5). Mostly, women had the responsibility to supply water into different places. Farmers made good use of water from the rivers. They sowed seeds after the rivers had flooded the fields, as floodwater made the soil rich. They planted different crops for winter (which was mild and wet) and summer (which was hot and dry). They were probably the first farmers to take water from underground wells. They may have used river water to irrigate their fields. Their main cultivation products, amongst others, were peas, sesame seed, and cotton. They also domesticated wild animals in order to use them for harvesting their farms [18].
Hydraulic modelling of irrigation canals for improved flow conditions in surface irrigation systems
Published in ISH Journal of Hydraulic Engineering, 2023
Joshua Wanyama, Erion Bwambale
Canal lining can have a significant effect on conveyance efficiency. Canal lining involves covering the sides and bottom of the canal with a water-tight material, such as concrete or asphalt. This helps to reduce seepage and evaporation, which can significantly increase the conveyance efficiency of the canal. With less water lost to seepage and evaporation, more water can be conveyed to its destination. Additionally, lining canals can also help to improve water quality by reducing the amount of sediment and other pollutants that are transported in the water. This can help to reduce the need for frequent desilting, which can be costly and time-consuming. However, it is important to note that the benefits of canal lining must be balanced against the potential negative impacts on the environment and the overall sustainability of the canal network. For example, lining canals can reduce the amount of water available for downstream users and can impact the downstream ecosystem. Additionally, canal lining can be expensive and may not be feasible in certain areas due to the topography or the presence of underground water resources.
A guideline for sustainable irrigation water management: a case of a developing country
Published in Intelligent Buildings International, 2021
D. C. Sirimewan, Aparna Samaraweera, N. H. C. Manjula, E. M. A. C. Ekanayake
Leakages and canal erosion cause losses in water conveyance and distribution canals. The concrete lining would be the optimal solution to avoid this problem since it has higher water carrying capacity in contrast to the earth canals. However, the decision on whether or not to do the lining of canals with concrete is decided on the type of underlying soil. Even though it reduces water losses along the canals and improves efficiency, it would adversely affect the groundwater table and associated catchment area that imperil to environmental sustainability. Thus, there shall be a trade-off between the requirement of the concrete lining of canals and the environmental aspects. The ‘trapezoidal section’ is the ideal section for conveying water in canals at the optimum speed. The advantage of having a trapezoidal section is the friction force of water is less in these types of canals than in canals having a rectangular section. Further, ‘cascade structures’ can be built within the canal itself with a concrete lining to avoid water loss due to improper drainage.
Drone survey facilitated weeds assessment and impact on hydraulic efficiency of canals
Published in ISH Journal of Hydraulic Engineering, 2021
Irrigation canals transport water from source to the farmers’ fields. The discharge is the volume of water that is transported each second. Where more fields that are served by a canal, more water has to be transported. The rate at which water is transported by a canal is called its discharge, and the maximum discharge that any canal can transport is called canal capacity. As per basic hydraulic principles, the continuity equation is applicable for all flow types without any restriction. For steady-state flow, discharge along the canal should be constant and it can be represented by continuity principle as follows (Depeweg et al. 2014):