Canal lining

Last updated September 11, 2024

Canal lining is the process of reducing seepage loss of irrigation water by adding an impermeable layer to the edges of the trench. Seepage can result in losses of 30 to 50 percent of irrigation water from canals, so adding lining can make irrigation systems more efficient. Canal linings are also used to prevent weed growth, which can spread throughout an irrigation system and reduce water flow. Lining a canal can also prevent waterlogging around low-lying areas of the canal.^[1]

By making a canal less permeable, the water velocity increases resulting in a greater overall discharge. Increased velocity also reduces the amount of evaporation and silting that occurs, making the canal more efficient.^[1] The oldest known paved canal was discovered in 1995 near the pyramids of Giza, and is estimated to be around 4,500 years old.^[2]

Canal lining types

Concrete

Concrete canal lining is often used due to its high structural strength and longevity. Concrete used for canal lining is typically non-reinforced, as a way to reduce cost. A common method for constructing concrete lining is the use of slip forms, which are drawn down the length of the canal as the concrete is poured.^[3] Hand laying of concrete or prefabricated sections are also used when only a short distance needs to be covered.^[3] Certain additives, such as kankar lime and surkhi, are sometimes included in the concrete mixture to improve water retention.^[3]

Prior to constructing concrete linings, it is common practice to ensure the sub-grade layer of soil is adequately consolidated.^[4] If expansive clay is located on the site of a canal, a layer of this clay is removed and replaced with sand or gravel before the concrete lining is constructed. This removal minimizes the risk of ground swelling, which can cause cracking in the concrete. In order to prevent cracking during the curing process, water is sprinkled on the concrete or a damp cover is placed over the lining. Another preventative measure against cracking, includes adding transverse and longitudinal grooves or expansion joints which help absorb cracking that may occur.^[3]

Compacted soil

Compacted clay is a simple form of soil canal lining, which serves as a relatively cheap alternative to other methods. Certain clays, such as bentonite, have high water absorption but then become impervious, which makes them an ideal soil lining. It has been shown through studies done in the U.S., that a layer of bentonite 2 to 5 cm thick, underneath a layer of earth 15 to 30 cm thick, makes for an adequate lining system. Typically, porous soils are removed before compacted clay is applied to the bed and sides of a canal.^[3]

Another simple method of canal lining with soils entails applying a layer of compacted silt on top of the subgrade of the canal.^[3] The use of soils as canal linings is efficient for controlling seepage, but not effective against weed growth.^[1]

Plastic membrane

Plastic linings are often referred to as geomembranes or flexible membrane linings.^[5] Plastic linings are often covered with soil, rocks, brick, concrete or other material. This is done in order to anchor the lining down and to protect it from deterioration and disintegration. Plastic membranes are very thin, varying in thickness from 8 up to 100 thousandths of an inch.^[5] Low-density polyethylene (LDPE) film, similar to the material used in trash bags, is a common type of plastic membrane used. Plastic linings are also used as a method of retrofitting damaged concrete linings.

Potential damage to canal linings

Since canal linings are exposed to the elements and are in constant use, they are susceptible to damage over time. Geotechnical considerations are often ignored in designing canal linings due to the light weight of the structure. Concrete canal linings often experience cracking, which can be expensive to repair. Cracking can occur through several ways, starting during construction if the concrete is cured improperly. Cracking can also occur due to movement of the soil, which can be caused by frost heave or the swelling of expansive soils. Expansive soils, such as certain types of clay, may swell as a result of canal discharge, changing climates or transpiration. A common method to reduce future swelling in expansive soils is to subject the soil to wetting and drying cycles prior to construction of the lining.^[6] Lab testing has shown that subjecting a clayey soil to wetting and drying cycles leads to a hysteresis of shrinkage in the soil, significantly reducing its free swelling potential.^[7] Dispersive soils, such as fine graded sands, can also pose a threat to concrete canal linings since they erode when in contact with flowing water, which can cause piping. As a way to reduce the potential for this contact to occur, geomembrane sheets can be installed underneath concrete linings, thus reducing the amount of water that may seep through the canal.^[8]

Related Research Articles

Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, Al₂Si₂O₅(OH)₄). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide.

An earth shelter, also called an earth house, earth bermed house, or underground house, is a structure with earth (soil) against the walls, on the roof, or that is entirely buried underground.

Bentonite is an absorbent swelling clay consisting mostly of montmorillonite which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-montmorillonite.

A road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, macadam, hoggin, cobblestone and granite setts were extensively used, but these have mostly been replaced by asphalt or concrete laid on a compacted base course. Asphalt mixtures have been used in pavement construction since the beginning of the 20th century and are of two types: metalled (hard-surfaced) and unmetalled roads. Metalled roadways are made to sustain vehicular load and so are usually made on frequently used roads. Unmetalled roads, also known as gravel roads or dirt roads, are rough and can sustain less weight. Road surfaces are frequently marked to guide traffic.

In geotechnical engineering, soil structure describes the arrangement of the solid parts of the soil and of the pore space located between them. It is determined by how individual soil granules clump, bind together, and aggregate, resulting in the arrangement of soil pores between them. Soil has a major influence on water and air movement, biological activity, root growth and seedling emergence. There are several different types of soil structure. It is inherently a dynamic and complex system that is affected by different factors.

A paver is a paving stone, tile, brick or brick-like piece of concrete commonly used as exterior flooring. They are generally placed on top of a foundation which is made of layers of compacted stone and sand. The pavers are placed in the desired pattern and the space between pavers is then filled with a polymeric sand. No actual adhesive or retaining method is used other than the weight of the paver itself except edging. Pavers can be used to make roads, driveways, patios, walkways and other outdoor platforms.

A leachate is any liquid that, in the course of passing through matter, extracts soluble or suspended solids, or any other component of the material through which it has passed.

Geosynthetics are synthetic products used to stabilize terrain. They are generally polymeric products used to solve civil engineering problems. This includes eight main product categories: geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, geofoam, geocells and geocomposites. The polymeric nature of the products makes them suitable for use in the ground where high levels of durability are required. They can also be used in exposed applications. Geosynthetics are available in a wide range of forms and materials. These products have a wide range of applications and are currently used in many civil, geotechnical, transportation, geoenvironmental, hydraulic, and private development applications including roads, airfields, railroads, embankments, retaining structures, reservoirs, canals, dams, erosion control, sediment control, landfill liners, landfill covers, mining, aquaculture and agriculture.

A smectite is a mineral mixture of various swelling sheet silicates (phyllosilicates), which have a three-layer 2:1 (TOT) structure and belong to the clay minerals. Smectites mainly consist of montmorillonite, but can often contain secondary minerals such as quartz and calcite.

Puddling is both the material and the process of lining a water body such as a channel or pond with puddle clay – a watertight material based on clay and water mixed to be workable.

Expansive clay is a clay soil that is prone to large volume changes that are directly related to changes in water content. Soils with a high content of expansive minerals can form deep cracks in drier seasons or years; such soils are called vertisols. Soils with smectite clay minerals, including montmorillonite and bentonite, have the most dramatic shrink–swell capacity.

<span class="mw-page-title-main">Pond liner</span>

A pond liner is an impermeable geomembrane used for retention of liquids, including the lining of reservoirs, retention basins, hazardous and nonhazardous surface impoundments, garden ponds and artificial streams in parks and gardens.

A geomembrane is very low permeability synthetic membrane liner or barrier used with any geotechnical engineering related material so as to control fluid migration in a human-made project, structure, or system. Geomembranes are made from relatively thin continuous polymeric sheets, but they can also be made from the impregnation of geotextiles with asphalt, elastomer or polymer sprays, or as multilayered bitumen geocomposites. Continuous polymer sheet geomembranes are, by far, the most common.

<span class="mw-page-title-main">Geosynthetic clay liner</span> Type of hydraulic barrier

Geosynthetic clay liners (GCLs) are factory manufactured hydraulic barriers consisting of a layer of bentonite or other very low-permeability material supported by geotextiles and/or geomembranes, mechanically held together by needling, stitching, or chemical adhesives. Due to environmental laws, any seepage from landfills must be collected and properly disposed of, otherwise contamination of the surrounding ground water could cause major environmental and/or ecological problems. The lower the hydraulic conductivity the more effective the GCL will be at retaining seepage inside of the landfill. Bentonite composed predominantly (>70%) of montmorillonite or other expansive clays, are preferred and most commonly used in GCLs. A general GCL construction would consist of two layers of geosynthetics stitched together enclosing a layer of natural or processed sodium bentonite. Typically, woven and/or non-woven textile geosynthetics are used, however polyethylene or geomembrane layers or geogrid geotextiles materials have also been incorporated into the design or in place of a textile layer to increase strength. GCLs are produced by several large companies in North America, Europe, and Asia. The United States Environmental Protection Agency currently regulates landfill construction and design in the US through several legislations.

An embankment dam is a large artificial dam. It is typically created by the placement and compaction of a complex semi-plastic mound of various compositions of soil or rock. It has a semi-pervious waterproof natural covering for its surface and a dense, impervious core. This makes the dam impervious to surface or seepage erosion. Such a dam is composed of fragmented independent material particles. The friction and interaction of particles binds the particles together into a stable mass rather than by the use of a cementing substance.

A landfill liner, or composite liner, is intended to be a low permeable barrier, which is laid down under engineered landfill sites. Until it deteriorates, the liner retards migration of leachate, and its toxic constituents, into underlying aquifers or nearby rivers from causing potentially irreversible contamination of the local waterway and its sediments.

The shrink–swell capacity of soils refers to the extent certain clay minerals will expand when wet and retract when dry. Soil with a high shrink–swell capacity is problematic and is known as shrink–swell soil, or expansive soil. The amount of certain clay minerals that are present, such as montmorillonite and smectite, directly affects the shrink-swell capacity of soil. This ability to drastically change volume can cause damage to existing structures, such as cracks in foundations or the walls of swimming pools.

<span class="mw-page-title-main">Cellular confinement</span> Confinement system used in construction and geotechnical engineering

Cellular confinement systems (CCS)—also known as geocells—are widely used in construction for erosion control, soil stabilization on flat ground and steep slopes, channel protection, and structural reinforcement for load support and earth retention. Typical cellular confinement systems are geosynthetics made with ultrasonically welded high-density polyethylene (HDPE) strips or novel polymeric alloy (NPA)—and expanded on-site to form a honeycomb-like structure—and filled with sand, soil, rock, gravel or concrete.

Colloid-facilitated transport designates a transport process by which colloidal particles serve as transport vector of diverse contaminants in the surface water and in underground water circulating in fissured rocks (limestone, sandstone, granite, ...). The transport of colloidal particles in surface soils and in the ground can also occur, depending on the soil structure, soil compaction, and the particles size, but the importance of colloidal transport was only given sufficient attention during the 1980 years. Radionuclides, heavy metals, and organic pollutants, easily sorb onto colloids suspended in water and that can easily act as contaminant carrier.

The Pench River is an Indian tributary of the Kanhan River. It originates in the Chhindwara district of Madhya Pradesh and flows across Pench National Park, which is a reserve for the Tiger Project of India.

References

1 2 3 Basak (1999-10-01). Irrigation Engineering. Tata McGraw-Hill Education. ISBN 9780074635384.
↑ "Oldest Paved Canal Uncovered In Egypt". tribunedigital-chicagotribune. Retrieved 2016-03-30.
1 2 3 4 5 6 Michael, A. M. (2009-11-01). Irrigation: Theory and Practice. Vikas Publishing House Pvt Ltd. ISBN 9788125918677.
↑ Kraatz, D. B. (1977-01-01). Irrigation canal lining. Food and Agriculture Organization of the United Nations. ISBN 9789251001653.
1 2 Gary, Merkley (2016-03-28). "Canal Linings" (PDF). Utah State University. Utah State University. Archived from the original (PDF) on 2016-03-28.
↑ Bonab, Masoud; Sarand, Fariba; Farrin, Majid (2012). Unsaturated Soils: Research and Applications Volume 2. Springer. pp. 308–314. ISBN 978-3-642-31343-1.
↑ Ahmadi, Hojjat; Rahimi, Hassan; Rostami, Maryam (16 April 2012). "Control of Swelling of Soil Under Canal Lining by Wetting and Drying Cycles". Irrigation and Drainage. doi:10.1002/ird.1666.
↑ Rahimi, Hassan; Abbasi, Nader; Shantia, Hassan (30 July 2010). "Application of Geomembrane to Control Piping of Sandy Soil Under Concrete Canal Lining". Irrigation and Drainage. doi:10.1002/ird.574.

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[:2-1] 1 2 3 Basak (1999-10-01). Irrigation Engineering. Tata McGraw-Hill Education. ISBN 9780074635384.

[2] "Oldest Paved Canal Uncovered In Egypt". tribunedigital-chicagotribune. Retrieved 2016-03-30.

[:0-3] 1 2 3 4 5 6 Michael, A. M. (2009-11-01). Irrigation: Theory and Practice. Vikas Publishing House Pvt Ltd. ISBN 9788125918677.

[4] Kraatz, D. B. (1977-01-01). Irrigation canal lining. Food and Agriculture Organization of the United Nations. ISBN 9789251001653.

[:1-5] 1 2 Gary, Merkley (2016-03-28). "Canal Linings" (PDF). Utah State University. Utah State University. Archived from the original (PDF) on 2016-03-28.

[6] Bonab, Masoud; Sarand, Fariba; Farrin, Majid (2012). Unsaturated Soils: Research and Applications Volume 2. Springer. pp. 308–314. ISBN 978-3-642-31343-1.

[7] Ahmadi, Hojjat; Rahimi, Hassan; Rostami, Maryam (16 April 2012). "Control of Swelling of Soil Under Canal Lining by Wetting and Drying Cycles". Irrigation and Drainage. doi:10.1002/ird.1666.

[8] Rahimi, Hassan; Abbasi, Nader; Shantia, Hassan (30 July 2010). "Application of Geomembrane to Control Piping of Sandy Soil Under Concrete Canal Lining". Irrigation and Drainage. doi:10.1002/ird.574.

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