Determination of optimum stream size and … In the late 1970s, a high-speed microcomputer technology began to emerge that could solve the basic equations describing the overland flow of water quickly and inexpensively. 2. Basin irrigation has a number of limitations, two of which, already mentioned, are associated with soil crusting and crops that cannot accommodate inundation. Surface irrigation has evolved into an extensive array of configurations which can be broadly classified as: (1) basin irrigation; (2) border irrigation; (3) furrow irrigation; and (4) uncontrolled flooding. The focus of surface irrigation engineering is at the water use level, the individual irrigated field. Under border check irrigation, water will directly wet the entire surface as the whole bay area is designed as the flow path. A smaller wetted area reduces evaporation losses. Land preparation is largely a land grading problem which will be discussed in Section 5. The process of surface irrigation can be described using four phases. for optimal performance Flooding • Definition/Description • Advantages – – • Disadvantages – – Graded borders • Covers entire surface • Used for close-growing crops • Slopes: 0.5% - 4% – What is wrong with a steeper slope? Most surface irrigation systems derive their water supplies from canal systems operated by public or semi-public irrigation departments, districts, or companies. Conveying water to the field requires similar structures to those found in major canal networks. 2.4 Surface irrigation The management of water in the field channels involves flow measurement, sediment and debris removal, divisions, checks, drop-energy dissipators, and water level regulators. Water infiltrates through the wetted perimeter and spreads vertically and horizontally to refill the soil reservoir. In Surface Irrigation, water is applied and distributed over the soil surface by the help of gravity. The changes in the lesser-developed and developing countries are less dramatic. Most fields have a head ditch or pipeline running along the upper side of the field from which the flow is distributed onto the field. As water is applied to the top end of the field it will flow or advance over the field length. performance, 2.3.2 Wastewater recovery Estimation of the infiltration rate using the infiltrometer method 5 1.3.2. Opportunities for Improving Irrigation Efficiency and Uniformity– 1. Basins and borders usually receive water through buried pipes serving one or more gated risers within each basin or border. Water is applied to individual borders from small hand-dug checks from the field head ditch. Designs for flow measurement and drop-energy dissipator structures need more attention and construction must be more precise since their hydraulic responses are quite sensitive to their dimensions. Level basin irrigation has historically been used in small areas having level surfaces that are surrounded by earth banks. Water is applied to the top end of each furrow and flows down the field under the influence of gravity. Figure 8. and reuse, 2.4.2 Elevated concrete channel in Iran, Figure 9. 2.1.1 Definition. The water is applied rapidly to the entire basin and is allowed to infiltrate. A volume balance approach to determine the parameters of the Kostiakov or modified Kostiakov infiltration equations in border and furrow irrigation is presented. Typical irrigation system components (redrafted from USDA-SCS, 1967). While surface irrigation can be practiced effectively using the correct management under the right conditions, it is often associated with a number of issues undermining productivity and environmental sustainability:[6]. Implementing management practices to control the discharge of irrigation water, tile drain water, stormwater, nutrients, pesticides, and sediments will continue to be important for all growers. Even today it is often more economical to regulate the inflow rather than to collect and pump the runoff back to the head of the field or to another field, tailwater reuse systems are more cost-effective when the water can be added to the flow serving lower fields and thereby saving the cost of pumping. Two typical examples are shown in Figure 3, which illustrate the most common basin irrigation concept: water is added to the basin through a gap in the perimeter dyke or adjacent ditch. Basins can be served with less command area and field watercourses than can border and furrow systems because their level nature allows water applications from anywhere along the basin perimeter. Probably the most interesting evolution in surface irrigation so far as this guide is concerned is the development and application of microcomputers and programmable calculators to the design and operation of surface irrigation systems. The crop is planted on the ridge between furrows which may contain a single row of plants or several rows in the case of a bed type system. In this paper, the same basic procedures are applied to the design of various surface systems, deviating where needed to make the procedures both straightforward and sufficiently accurate. The general surface irrigation process includes four phases: advance, storage, depletion, and recession (Holzapfel et al. The discharge per unit width of the field is substantially reduced and topographical variations can be more severe. The precision of the field topography is also critical, but the extended lengths permit better levelling through the use of farm machinery. The process of surface irrigation can be said to include four phases: advance phase; storage phase; depletion phase; and recession phase. 2.4.3 Field distribution 2. 2.4.2 There are several disadvantages with furrow irrigation. Surface irrigation is where water is applied and distributed over the soil surface by gravity. Phase 1, when the water dalirkan to land, there will be the addition of water on the surface of the land to flooding the entire surface of the land. It is useful to note here that in observing surface irrigation one may not always observe a ponding, depletion or recession phase. Drain back level basins (DBLB) or contour basins are a variant of basin irrigation where the field is divided into a number of terraced rectangular bays which are graded level or have no significant slope. The speed of water movement is determined by many factors such as slope, surface roughness and furrow shape but most importantly by the inflow rate and soil infiltration rate. If a field is level in all directions, is encompassed by a dyke to prevent runoff, and provides an undirected flow of water onto the field, it is herein called a basin. The attention here then is focused on inflow regulation and tailwater control. In basins, for example, the post-cut off period may only involve a depletion phase as the water infiltrates vertically over the entire field. A very large number of causes of poor surface irrigation performance have been outlined in the technical literature. The most common piped method of furrow irrigation uses plastic or aluminium gated pipe like that shown in Figure 14. In traditional basins no water is permitted to drain from the field once it is irrigated. The surface irrigation system is one component of a much larger network of facilities diverting and delivering water to farmlands. Phase 2, then the irrigation water will flow out of the land. 2. Water is applied to the first bay (usually the highest in elevation) and when the desired depth is applied water is permitted to drain back off that bay and flow to the next bay which is at a lower elevation than the first. Surface irrigation systems are supported by a number of on- and off-farm structures which control and manage the flow and its energy. A surface irrigation event is composed of four phases as illustrated graphically in Figure 1. Very large mechanized farming equipment has replaced animal-powered planting, cultivating and harvesting operations. It may be divided into the following four component systems: (1) water supply; (2) water conveyance or delivery; (3) water use; and (4) drainage. Subirrigation is the distribution of water to soil below the surface; it provides moisture to crops by upward capillary action. The precision of preparing the field for planting has improved by an order of magnitude with the advent of the laser-controlled land grading equipment. Figure 11. A basin is typically square in shape but exists in all sorts of irregular and rectangular configurations. In those cases where high levels of uniformity and efficiency are being achieved, irrigators utilize one or more of the following practices: (1) precise and careful field preparation; (2) irrigation scheduling; (3) regulation of inflow discharges; and (4) tailwater runoff restrictions, reduction, or reuse. The aim of modern surface irrigation management is to minimize the risk of these potential adverse impacts. How large are the fields? Reuse systems have not been widely employed historically because water and energy have been inexpensive. Large difference in water that crops require and the flow irrigation system actually delivers results in low field water application efficiency. The volume of water on the surface begins to decline after the water is no longer being applied. What methods are used? The higher inflow reaches the end of the field sooner but it increases both the duration and the magnitude of the runoff. It may be furrowed or corrugated, have raised beds for the benefit of certain crops, but as long as the inflow is undirected and uncontrolled into these field modifications, it remains a basin. The wetting and drying cycles reduce infiltration rates resulting in faster advance rates and higher uniformity[3] than continuous flow. Surface irrigation systems have two principal sources of inefficiency, deep percolation and surface runoff or tailwater The remedies are competitive. For borders and basins, open or piped cutlets as illustrated in Figure 11 are generally used. Typical irrigated basins (from Walker and Skogerboe, 1987). The advance phase refers to that length of time as water is applied to the top end of the field and flows or advances over the field length. Reclamation of salt-affected soils is easily accomplished with basin irrigation and provision for drainage of surface runoff is unnecessary. … Successful operation of these systems is reliant on a sufficient elevation drop between successive bays. Most of these farmers own and operate farms of 1-10 hectares, irrigate with 20-40 litres per second and rely on either small mechanized equipment or animal-powered farming implements. Furrow irrigation is particularly suited to broad-acre row crops such as cotton, maize and sugar cane. Before selecting surface irrigation over other types of irrigations, one must investigate the advantages and disadvantages of surface irrigation. 2.2.3 Furrow irrigation These systems are commonly used in Australia where rice and wheat are grown in rotation.[2]. It either drains from the surface (runoff) or infiltrates into the soil. The water is applied to the top end of the bay, which is usually constructed to facilitate free-flowing conditions at the downstream end. Surface irrigation systems are best suited to soil with low to moderate infiltration capacities and land with relatively uniform terrain and slope less than 2 to 3 percent (Booher, 1974). In: Annual Report 1988, International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands, pp. Diversion structures perform several tasks including (1) on-off water control which allows the supply agency to allocate its supply and protects the fields below the diversion from untimely flooding; (2) regulation and stabilization of the discharge to the requirements of field channels and watercourse distribution systems; (3) measurement of flow at the turnout in order to establish and protect water entitlements; and (4) protection of downstream structures by controlling sediments and debris as well as dissipating excess kinetic energy in the flow. The classification of surface methods is perhaps somewhat arbitrary in technical literature. Many basins are so small that precision equipment cannot work effectively. Figure 2. It is by far the most common form of irrigation throughout the world and has been practiced in many areas virtually unchanged for thousands of years. Figure 2 illustrates the 'irrigation system' and some of its features. Surface irrigation has evolved into an extensive array of configurations that can broadly be classified as: • basin irrigation • border irrigation • furrow irrigation • wild flooding The distinction between the various classifications is often subjective. It is also practiced in various horticultural industries such as citrus, stone fruit and tomatoes. The Physical systems of Surface irrigation systems as a whole consist of four subsystems. The designs of these structures have been standardized since they are small in size and capacity. On-farm water management structures (from Skogerboe Increasing the advance rate not only improves the uniformity but also reduces the total volume of water required to complete the irrigation. The incidence of surface irrigation process consists of four phases, as illustrated in Figure 7 below. Figure 7. 4. Each bay is irrigated in turn using a combination of drainage water from the previous bay and continuing inflow from the supply channel. 2.2.4 Uncontrolled flooding. Is laser guided land leveling used in Iraq? For example, a basin or border system may be furrowed. Head ditch outlets for borders and basins (after Kraatz and Mahajan, FAO, 1975). The water can take a considerable period of time to reach the other end, meaning water has been infiltrating for a longer period of time at the top end of the field. Furrows provide better on-farm water management flexibility under many surface irrigation conditions. Pipe materials are usually plastic, steel, concrete, clay, or asbestos cement, or they may be as simple as a wooden or bamboo construction. The period of time between the end of the advance phase and the shut-off of the inflow is termed the wetting, ponding or storage phase. Figure 5. 2.1 Introduction 1.2. Likewise, in the irrigation of paddy rice, an irrigation very often adds to the ponded water in the basin so there is neither advance nor recession - only wetting or ponding phase and part of the depletion phase. The depletion phase is that short period of time after cut-off when the length of the field is still submerged. In furrow systems, the volume of water in the furrow is very often a small part of the total supply for the field and it drains rapidly. As water is applied to the top end of the field it will flow or advance over the field length. Figure 5 shows two typical furrow irrigated conditions. However, this practice increases the tailwater problem because the flow at the downstream end must be maintained until a sufficient depth has infiltrated. Chapter 4 Surface Irrigation Part 623 NationalEngineeringHandbook (210–VI–NEH, September 2012) 4–v Figures Figure 4–1 Layout and function of irrigation system components 4–2 Figure 4–2 Basic phases of a surface irrigation event 4–3 Figure 4–3 Typical basin irrigation system in the Western United States 4… The interval between the end of the advance and when the inflow is cut off is called the wetting or ponding phase. • Strip widths ~ 30 to 60 ft – What is wrong with wide borders? For the purposes of describing the hydraulics of the surface flows, the drainage period is segregated into the depletion phase (vertical recession) and the recession phase (horizontal recession). The WinSRFR program, In general, it is more labour intensive than other irrigation methods. Time-space trajectory of water during a surface irrigation showing its advance, wetting, depletion and recession phases. Water levels are regulated in two bays simultaneously so that the lower bay has sufficient head to produce an advance phase flow in the furrows while in the upper bay the head is only sufficient to produce the cutback flow. Shorter furrows are commonly associated with higher uniformity of application but result in increasing potential for runoff losses. These are: 1) The water supply subsystem 2) The water delivery subsystem 3) The water use subsystem Needs Assessment --1. The four phases of surface irrigation 3 1.2.1. to surface irrigation 3. Figure 4 illustrates a typical border configuration in which a field is divided into sloping borders. Surface irrigation events have 3 phases: advance, storage, and recession. Surface irrigation methods are the oldest, and are those that use the soil surface to conduct and infiltrate the applied water. This results in poor uniformity with high application at the top end with lower application at the bottom end. Figure 12 shows a system in which siphon tubes are used as a means of serving each furrow. Surface water and groundwater monitoring and reporting programs are also likely to … The depletion phase 4 1.2.4. Here, we will not detail out sub surface irrigation methods. The tailwater deep percolation trade-off can also be solved by collecting and recycling the runoff to improve surface irrigation performance. Field distribution and spreading can also be through portable pipelines running along the surfaces or permanent pipelines running underground. Furrows are often employed in basins and borders to reduce the effects of topographical variation and crusting. The effectiveness of existing practices or proposed ones can be predicted, even to the extent that control systems operating, sensing and adjusting on a real-time basis are possible. Conveyance, distribution and management structures When water is applied to the field, it 'advances' across the surface until the water extends over the entire area. The storage or ponding phase 3 1.2.3. 2.2.2 Border irrigation At about the same time, researchers like Strelkoff and Katapodes (1977) made major contributions with efficient and accurate numerical solutions to these equations. Soils can be efficiently irrigated which have moderately low to moderately high intake rates but, as with basins, should not form dense crusts unless provisions are made to furrow or construct raised borders for the crops. Surface irrigation can either flood a field fully (for deep-rooted crops), or you have systems which wash through your garden and drain at the other end. Surface irrigation methods include furrow, border, and basin irrigation (Figs. However, in looking for a root cause, one most often retreats to the fact that infiltration changes a great deal from irrigation to irrigation, from soil to soil, and is neither predictable nor effectively manageable. When the water is shut off, it recedes from the upper end to the lower end. Some irrigation water is supplied in piped delivery systems and some directly pumped from groundwater. This chapter uses volume balance methods to design surface irrigation systems. Crops which are sensitive to flooding and soils which form a hard crust following an irrigation can be basin irrigated by adding furrowing or using raised bed planting. Typical bay dimensions are between 10-70m wide and 100-700m long. There are few crops and soils not amenable to basin irrigation, but it is generally favoured by moderate to slow intake soils, deep-rooted and closely spaced crops. The stream size per unit width must be large, particularly following a major tillage operation, although not so large for basins owing to the effects of slope. Recession begins at that point and continues until the surface is drained. As the inf… Surface irrigation is an irrigation type where gravity force is used to distribute water over the soil surface. FLOOD IRRIGATION includes several methods: Border strip, basin, contour or bench border irrigation, flooding from contour ditches, wild flooding, and border ditch. Automation is easily applied. ILRI, 1989, Effectiveness and Social/Environmental Impacts of Irrigation Projects: a Review. The soil acts as the growing medium in which water is stored and the conveyance medium over which water flows as it spreads and infiltrates. systems. Surface irrigation is often referred to as flood irrigation, implying that the water distribution is uncontrolled and therefore, inherently inefficient. 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