Drainage Systems (Essay Sample)

Water Drainage Techniques Materials and Maintenance
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Water Drainage Techniques, Materials and Maintenance
Introduction
It is undisputable fact that during rainy seasons, drainage becomes a common term to virtually every one. At such times, poor drainage is attributed to virtually every harmful effect emanating from the heavy rains. For instance, poor drainage systems are attributed to flooding of settlement areas, especially in urban and slum areas in majority of the developing nations. Furthermore, poor drainage is also attributed to damage of crops and roads, as well as to the outbreak of diseases such as cholera. However, majority of mere laymen have little understanding as to what water drainage entails.
Drainage is understood differently depending on the background from which one comes from. From an agricultural background, drainage refers to the controlled removal of excess water in water-logged soils in order to support agricultural activities.1 On the other hand, from a mining perspective, drainage refers to removal of acidic water commonly known as Acidic Mine Removal (AMD), which is a result of excess minerals dissolving in water (Simonovic, 2012). In that line, this paper explores the various available water drainage techniques. In subsequent sections, materials that are used in water drainage systems and the necessary maintenance practices are outlined.
Water Drainage Techniques
Over the years, various water drainage techniques have been developed. To begin with, surface drainage is one of the conventional drainage techniques. It involves excavation of open trenches that are intended to divert water to major drains or natural streams. In addition, it may involve construction of broad-based ridges, and the being discharged through the troughs between the beds (Simonovic, 2012). According to a research conducted by Moorepark Animal and Grassland Research and Innovation Centre, MAGRIC, this method is more effective on heavier soils such as clay, where rainfall cannot percolate freely through the soil profile to the water table. Up to date, surface drainage remains to be the widely drainage technique, especially in humid and sub-humid areas.2
Secondly, horizontal subsurface drainage technique is another conventional drainage that is commonly used. According to Simonovic 2012, this method simply entails the removal of excess water from below the earth’s surface. In a typical horizontal subsurface drainage, the field drains are open ditches that are dug to mobilize water at a single location. Alternatively, a network of horizontal pipes is installed underground. These pipes used to be constructed from clay tiles before the introduction of plastic drainage pipes. In this technique, the water enters the pipes through the leaky joints and it flows to the main drain. Despite its drawback of possible disposable of a large content of nutrient, this method has been found to be highly effective in the control of underground water table and enabling highly productive agriculture.3
Lastly, vertical subsurface drainage is yet another drainage control technique. In this method, groundwater is through pumping from boreholes and tube-wells. It should be noted that this can be accomplished either in a mono or multi-well configuration. This method is advantageous in the sense that excessively saline water can be mobilized in deep wells, posing disposal challenges (Tuohy, Fenton, O'Loughlin, and Humphreys, 2013). Nevertheless, this method has been widely used to mobilize irrigation water, especially in dry areas. As a result, salt and other minerals are recycled in the soil.
Materials applied in water drainage systems
It is worth noting that the quality and efficiency of drainage systems primarily depends on the type and quality of the materials that are used in their construction. In view of that, it is highly important for individuals to deeply understand the various types of drainage system materials. The most commonly used in drainage system materials include drain pipes, drainage stones, and backfill materials. The following is a detailed description of each of the materials.
Drain pipes provide a path where the discharge can flow freely with minimal resistance from the drain. Many people tend to ignore drainage pipes in their drainage systems, citing blockage problems (Tuohy, Fenton, O'Loughlin, and Humphreys, 2013). However, according to a research conducted by MAGRIC, only short drainage systems that are below 30 meters can operate without a pipe. Drainage pipe materials have evolved over the years. In earlier days, clay pipes were being used but they have nowadays been replaced by plastic pipes that dominate the industry. A good drainage pipe should be durable, strong, resistant to corrosion, and should allow free low of the discharge.4
Drainage stones serve many vital functions in a drainage system; thus their careful selection cannot be underrated if an efficient drainage system is anything to be realized. To begin with, they act as a bedding that supports the pipe; thus preventing its damage or collapse. Secondly, they act as a hydraulic medium that allows easier inflow of discharge into the pipe. Lastly, they act as filters; thus preventing entry of fine particles into the pipe. In view of that good drainage stones should be strong and be able to withstand deterioration. It is also important to note that too small stones hinder permeability. Conversely, too large stones pose handling problems and they may also damage the pipes.5 In that line, a research conducted by MAGIC has shown that the best drainage size should be 10-40 mm (Tuohy, Fenton, O'Loughlin, and Humphreys, 2013).
Backfill material is used to cover the stones and the drain pipe. When deciding to the type of backfill material to be used, the function of the drainage stones used should be the governing factor. The most commonly used backfill materials include soil and gravel. According to a research conducted by MAGRIC, horizontal subsurface drainage gravel should be filled to a minimum of 30 mm from the bottom to cover the drain pipe (Tuohy, Fenton, O'Loughlin, and Humphreys, 2013). The rest of the pipe can be filled with s...