Conserving Water with Enclosed Canals Using HDPE Pipes

How can conserving water with enclosed canals using HDPE pipes make a difference?

Canals have played a critical role in managing water resources for centuries, providing a means to transport water where it is needed most. However, canals present an opportunity for water conservation, especially as population density grows and water resources become scarce (1–3). 

A considerable amount of the water passing through earth canals can be lost before reaching their end, leading to significant economic losses (4, 5). For instance, the irrigation delivery organization in the United States reports a conveyance loss of 15% of the total water brought into their system in 2019 (6). In recent years, there has been growing interest in using enclosed canals to help conserve water. Within this context, enclosing canals with pipes can significantly reduce water loss due to evaporation and seepage (7). This technology can be particularly effective in cities where water demand is high and water resources are often limited. By conserving water through enclosed canals, cities can reduce the strain on local water resources and improve their resilience in the face of drought and other water-related challenges. 

This article explores the importance of water conservation and the role of canals in water management, arguing that enclosing canals with high-density polyethylene (HDPE) pipes can help cities conserve water. This article also examines the benefits of this technique, the challenges and limitations of its implementation, and the potential impact it can have on water conservation efforts in cities.

What are canals and how do they work? 

Canals are artificial waterways that are used to transport water for a variety of purposes. They are typically constructed by digging channels in the ground or building concrete or earthen embankments to contain the water. Canals can transport water for irrigation, drinking water, hydroelectric power generation, or other purposes. The primary function of canals is to move water from one place to another. They can transport water over long distances and can be used to connect different water sources. Canals can also regulate water flow and store water for later use (8). 

One of the ways that canals help manage water resources is by providing a means to transport water. In areas with limited water resources, canals may bring water from rivers or other sources to irrigate crops or provide drinking water. Canals can also transport water to hydroelectric power plants, where the water is used to generate electricity (9). By diverting water from rivers or other sources into canals, water can be stored and released when needed. This can be particularly useful in areas with seasonal rainfall patterns, where water may be abundant during certain times of the year but scarce during others. 

Challenges of open canals 

One of the significant challenges in open canals is water seepage (10). Open canals are highly susceptible to water loss when water seeps through the canal walls and base, reducing water availability for irrigation and other uses and increasing maintenance costs (11). Additionally, open canals are exposed to the atmosphere and are subject to significant water loss due to evaporation. The evaporation rate can be substantial in areas with high temperatures, low humidity, and high winds, resulting in substantial water losses that affect water availability for irrigation, drinking, and other uses. Water loss through evaporation can also reduce the efficiency of canals, increasing the water delivery cost. 

Open canals can also be a source of water contamination, as they are in direct contact with the external environment. The contamination can come from agricultural runoff, industrial waste, and sewage, affecting water quality (12). On the other hand, open canals are often built to manage water flow during the rainy season. However, they can also increase the risk of flooding, especially in areas with poor drainage systems where heavy rainfall or sudden water releases from upstream can cause the canal to overflow and cause flooding.

Conserving water with enclosed canals using HDPE pipes

HDPE pipes are produced from high-density polyethylene, a type of thermoplastic polymer that is strong, flexible, and corrosion-resistant (13–15). They are commonly used in the construction industry for various applications, including water supply and drainage systems, gas pipelines, and industrial piping systems (16). One of the main advantages of HDPE pipes is their high strength-to-density ratio, which means they are lightweight yet strong enough to withstand high pressures and heavy loads. They are also flexible, which makes them ideal for use in areas with high seismic activity, where they can bend and flex without cracking or breaking (17).

Enclosing canals with HDPE pipes can provide several advantages over traditional open canals, including reduced water loss, improved water quality, reduced flood risks, and increased efficiency (18). As mentioned above, open canals are susceptible to water loss due to evaporation, seepage, and leaks. Enclosing canals with HDPE pipes can significantly reduce these losses, as the pipes are completely sealed and do not allow any water to escape (19). This can help to conserve water resources and improve the reliability of water distribution systems. 

Additionally, enclosing canals with HDPE pipes can help prevent water contamination since the pipes provide a barrier between the water and the surrounding environment. This can improve the water supply’s quality and safety, reducing the risk of waterborne illnesses. Enclosing canals with HDPE pipes can also increase the efficiency of water distribution systems. Pipes can be designed to transport water more quickly and with less friction than open canals, reducing energy costs and improving the system’s overall performance.

Enclosing canals with HDPE pipes involves several steps, including planning, design, and construction. The first step is to evaluate the site and determine the optimal location and size for the enclosed canal. This may involve surveying the land, analyzing water flow patterns, and assessing potential environmental impacts. Once the site has been evaluated, the next step includes selecting the appropriate size and type of HDPE pipes, designing the pipe layout, and determining the necessary support structures. 

Once the design has been finalized, the construction phase can begin by excavating the canal bed, installing the support structures, and laying the HDPE pipes. The pipes are generally combined using various methods, such as butt fusion. Finally, the system can be tested for leaks by measuring water flow rates and assessing the system’s overall efficiency to meet the necessary performance standards.

Cost-benefit analysis of canal enclosure 

In general, canal enclosure projects offer a range of benefits, including reducing water loss through evaporation, reducing the risk of water contamination, and improving water efficiency (7). However, there are also costs involved in this process which vary depending on a range of factors, including the size of the canal, the materials used for the covering, and the complexity of the installation process (19). 

Overall, the feasibility of canal enclosure projects will depend on numerous factors, including the specific costs involved, the potential benefits, and the availability of funding. While canal enclosure projects can be costly at the installation stage, the benefits of improved water efficiency, reduced water loss, and enhanced safety can outweigh the costs. Table 1 summarizes the costs and benefits of such projects.

Generally, studies have shown that piping infrastructure can improve canal water availability at initial costs near that of acquiring new supplies. Additionally, canal enclosures have shown a higher return on investment compared with canal lining (Figure 1). When combined with the benefits of HDPE, including zero-leakage tolerance, the return of investment further increases. 

Conclusion 

Conserving water has become an increasingly important issue, especially in cities where water demand is high and water resources are often limited. One method for water conservation is enclosing canals with HDPE pipes to reduce water loss due to evaporation and seepage. To summarize:

• Enclosing canals with HDPE pipes can improve water quality, reduce flood risks, and increase the efficiency of water distribution systems while overcoming the issues of seepage and water evaporation.
• Implementing enclosed canals with HDPE pipes involves several steps, including planning, design, and construction. HDPE pipes can help cities conserve water and improve their resilience in the face of water-related challenges.
• The benefits of canal enclosure projects to the cities and stakeholders outweigh the costs involved.

Overall, canal enclosure with HDPE is a cost-effective and practical solution for reducing water loss, improving water efficiency and enhancing the safety of open canals used for irrigation. At the same time, it ensures a more sustainable and secure water supply for communities, particularly in arid, water-scarce, and seismic regions.

Figure and Tables

Table 1. Costs and benefits of canal enclosure (7, 19).

Figure 1. Cost comparison between lining canals or piping infrastructure for irrigation water supply (6).