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. Volume balance methods compare the applied volume to surface and subsurface storage volumes in order to calculate parameters such as infiltration rate or the rate of water advance down the field. Water infiltrates through the wetted perimeter and spreads vertically and horizontally to refill the soil reservoir. It is useful to note here that in observing surface irrigation one may not always observe a ponding, depletion or recession phase. This results in poor uniformity with high application at the top end with lower application at the bottom end. The spacing between adjacent furrows is governed by the crop species, common spacings typically range from 0.75 to 2 metres. Figure 11. Some irrigation water is supplied in piped delivery systems and some directly pumped from groundwater. Surface irrigation (Figure 12.1) of secondary treated and disinfected effluent is permitted in NSW. [5] The effectiveness of surge irrigation is soil type dependent; for example, many clay soils experience a rapid sealing behaviour under continuous flow and therefore surge irrigation offers little benefit.[1]. 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. for optimal performance, 2.1 Introduction to surface Water is applied to the top end of each furrow and flows down the field under the influence of gravity. Thus, surface irrigation may appear in several configurations and operate under several regimes. For example, a basin or border system may be furrowed. At about the same time, researchers like Strelkoff and Katapodes (1977) made major contributions with efficient and accurate numerical solutions to these equations. 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. Increasing the advance rate not only improves the uniformity but also reduces the total volume of water required to complete the irrigation. Thus, the system operates by moving the check-dam from bay to bay along the upper end of the field. Surface irrigation, an inexpensive and inefficient method of irrigating crops, wasting much of the water applied which needs to be optimized through advance techniques (Strelkoff and Clemens, 2003). 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. This has tended to make surface irrigation analysis and design appear disjointed. During advance, the water moves down the channel. 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). After the water reaches the end of the field it will either run-off or start to pond. The water is applied rapidly to the entire basin and is allowed to infiltrate. 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. Furrows are often employed in basins and borders to reduce the effects of topographical variation and crusting. Head ditch outlets for borders and basins (after Kraatz and Mahajan, FAO, 1975). 2. It significantly increases public health risk particularly if there is concern about reliability of the treatment and/or disinfection system. The process of surface irrigation can be said to include four phases: advance phase; storage phase; depletion phase; and recession phase. 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. The classification of surface methods is perhaps somewhat arbitrary in technical literature. The advance and recession curves are therefore trajectories of the leading and receding edges of the surface flows and the period defined between the two curves at any distance is the time water is on the surface and therefore also the time water is infiltrating into the soil. 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. 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. The bays are typically longer and narrower compared to basin irrigation and are orientated to align lengthwise with the slope of the field. It is widely utilised and therefore a well-known system, which can be operated without any high-tech applications. In Surface Irrigation, water is applied and distributed over the soil surface by the help of gravity. 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 time and space references shown in Figure 1 are relatively standard. These are generally situations where the value of the crop is very small or the field is used for grazing or recreation purposes. Surface water and groundwater monitoring and reporting programs are also likely to … How large are the fields? The higher inflow reaches the end of the field sooner but it increases both the duration and the magnitude of the runoff. 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. • Strip widths ~ 30 to 60 ft – What is wrong with wide borders? The gated pipe may be connected to the main water supply via a piped distribution network with a riser assembly like the one shown in Figure 13, directly to a canal turnout, or through an open channel to a piped transition. 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. A basin is typically square in shape but exists in all sorts of irregular and rectangular configurations. Very large mechanized farming equipment has replaced animal-powered planting, cultivating and harvesting operations. 2.3.1 Inlet discharge control Furrow irrigation is conducted by creating small parallel channels along the field length in the direction of predominant slope. Common surface irrigation systems used are rill irrigation, furrow or border irrigation. The conveyance itself can be an earthen ditch or lateral, a buried pipe, or a lined ditch. Time-space trajectory of water during a surface irrigation showing its advance, wetting, depletion and recession phases. Each surface system has unique advantages and disadvantages depending on such factors as were listed earlier like: (1) initial cost; (2) size and shape of fields; (3) soil characteristics; (4) nature and availability of the water supply; (5) climate; (6) cropping patterns; (7) social preferences and structures; (8) historical experiences; and (9) influences external to the surface irrigation system. 1.2. Issues associated with surface irrigation. 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. To minimize deep percolation the advance phase should be completed as quickly as possible so that the intake opportunity time over the field will be uniform and then cut the inflow off when enough water has been added to refill the root zone. It is not the intent of this guide to be comprehensive with regard to the selection and design of these structures since other sources are available, but it is worthwhile to note some of these structures by way of presenting a larger view of surface irrigation. Surface irrigation is where water is applied and distributed over the soil surface by gravity. Time is cumulative since the beginning of the irrigation, distance is referenced to the point water enters the field. Successful operation of these systems is reliant on a sufficient elevation drop between successive bays. 4. The Equations describing the hydraulics of surface irrigation are the continuity and momentum equation.These equations are known as the St.Venantequation.In general, the continuity equation expressing the conservation of mass, can be written as: (31.1) The momentum equation expressing the dynamic equilibrium of the flow process is: (31.2) Where, y - Depth of flow (m) t -Time from beginning … In the developed and industrialized countries, land holdings have become as much as 10-20 times as large, and the number of farm families has dropped sharply. As the inflow ceases the water will continue to runoff and infiltrate until the entire field is drained. For practical purposes, there may not be a depletion phase and recession can be ignored. The depletion phase is that short period of time after cut-off when the length of the field is still submerged. The reduction in infiltration is a result of surface consolidation, filling of cracks and micro pores and the disintegration of soil particles during rapid wetting and consequent surface sealing during each drying phase. 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. It may be divided into the following four component systems: (1) water supply; (2) water conveyance or delivery; (3) water use; and (4) drainage. The most common piped method of furrow irrigation uses plastic or aluminium gated pipe like that shown in Figure 14. Furrows may range anywhere from less than 100 m to 2000 m long depending on the soil type, location and crop type. In: Annual Report 1988, International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands, pp. Level basin irrigation has historically been used in small areas having level surfaces that are surrounded by earth banks. 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. Examples of these alternative practices are discussed and illustrated in Section 5. Of course it is always possible to encounter a heavy rainfall or mistake the cut-off time thereby having too much water in the basin. There are several disadvantages with furrow irrigation. 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. Reuse systems have not been widely employed historically because water and energy have been inexpensive. Typical bay dimensions are between 10-70m wide and 100-700m long. A very large number of causes of poor surface irrigation performance have been outlined in the technical literature. Advantages of Surface Irrigation . The structural elements of a surface system perform several important functions which include: (1) turning the flow to a field on and off; (2) conveying and distributing the flow among fields; (3) water measurement, sediment and debris removal, water level stabilization; and (4) distribution of water onto the field. Surface irrigation comes in three major types; level basin, furrow and border strip. The attention here then is focused on inflow regulation and tailwater control. What is surface irrigation in Iraq like today? Furrow irrigation avoids flooding the entire field surface by channelling the flow along the primary direction of the field using 'furrows,' 'creases,' or 'corrugations'. 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. Surface Irrigation. In basins, for example, the post-cut off period may only involve a depletion phase as the water infiltrates vertically over the entire field. However, this practice increases the tailwater problem because the flow at the downstream end must be maintained until a sufficient depth has infiltrated. Then the irrigation water either runs off the field or begins to pond on its surface. In most cases the performance of furrow irrigation can be improved through increasing the speed at which water moves along the field (the advance rate). In a field irrigated from a head ditch, the spreading of water over the field depends somewhat on the method of surface irrigation. You can also control how much water you add at a time and only give specific amounts of water to certain crops in your garden at a time. Figure 5 shows two typical furrow irrigated conditions. The object of border strip irrigation is to advance a sheet of water down a narrow strip between low ridges or borders and to get the water into the soil as the sheet advances. 2.2.1 Basin irrigation 2.4.2 systems. and reuse. One of the innovations in surface irrigation, the Needs Assessment --1. on for 1 hour off for 1½ hour). Phase 2, then the irrigation water will flow out of the land. et al., 1971). Surface Irrigation is a kind of irrigation where gravity works its best. Surface Irrigation Methods • Flooding • Borders • Basins • Furrows. In general, it is more labour intensive than other irrigation methods. There are three options available to solve this problem, at least partially: (1) dyke the downstream end to prevent runoff as in basin irrigation; (2) reduce the inflow discharge to a rate more closely approximating the cumulative infiltration along the field following the advance phase, a practice termed 'cutback'; or (3) select a discharge which minimizes the sum of deep percolation and tailwater losses, i.e., optimize the field inflow regime. Other articles where Surface irrigation is discussed: horticulture: Water management: In surface irrigation water is distributed over the surface of soil. Each should be standardized for mass production and fabrication in the field by farmers and technicians. Some of the more common flow control structures for open channels are shown in Figure 10. The movement of soil water curve . 2.4 Surface irrigation Each bay is irrigated in turn using a combination of drainage water from the previous bay and continuing inflow from the supply channel. This can be accomplished with a high, but non-erosive, discharge onto the field. Surface Irrigation is an unchanged process and it is older than its recognition. surface waters. It may or may not directly wet the entire surface, but all of the flow paths have been completed. The water is applied to the top end of the bay, which is usually constructed to facilitate free-flowing conditions at the downstream end. 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. In this configuration, the head ditch is divided into a series of level bays which are differentiated by a small change in elevation. The interval between the end of the advance and when the inflow is cut off is called the wetting or ponding phase. Is the water supply mainly from canals? … The wetting and drying cycles reduce infiltration rates resulting in faster advance rates and higher uniformity[3] than continuous flow. The term 'surface irrigation' refers to a broad class of irrigation methods in which water is distributed over the field by overland flow. Lining materials include slip-form cast-in-place, or prefabricated concrete (Figure 9), shotcrete or gunite, asphalt, surface and buried plastic or rubber membranes, and compacted earth. A surface irrigation event is composed of four phases as illustrated graphically in Figure 1. Surface irrigation is an irrigation type where gravity force is used to distribute water over the soil surface. Irrigation scheduling is a theme covered separately by several publications such as the FAO Irrigation and Drainage Paper 24 (Rev) by Doorenbos and Pruitt (FAO, 1977). Traditionally, the design and operation of surface irrigation systems are based on experience as well as on historically successful designs. Elevated concrete channel in Iran, Figure 9. Microcomputers and programmable calculators provide several features for today's irrigation engineers and technicians. If there is long duration between two rotations, there is likelihood of water stress resulting in wilting point during the recession stage. Land preparation is largely a land grading problem which will be discussed in Section 5. A smaller wetted area reduces evaporation losses. Surface irrigation is often referred to as flood irrigation, implying that the water distribution is uncontrolled and therefore, inherently inefficient. 3. Conveyance, distribution and management structures, 2.4.2 Conveyance, distribution and management structures. Here, we will not detail out sub surface irrigation methods. 2. For design and evaluation purposes, these guidelines will note elements of the conveyance and distribution system, especially those near the field such as flow measurement and control, but will leave detailed treatment to other technical sources. 18 - 34 . Shorter furrows are commonly associated with higher uniformity of application but result in increasing potential for runoff losses. The precision of the field topography is also critical, but the extended lengths permit better levelling through the use of farm machinery. Many basins are so small that precision equipment cannot work effectively. Pipe materials are usually plastic, steel, concrete, clay, or asbestos cement, or they may be as simple as a wooden or bamboo construction. The incidence of surface irrigation process consists of four phases, as illustrated in Figure 7 below. 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. for optimal performance The depletion phase 4 1.2.4. 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. When water is applied to the field, it 'advances' across the surface until the water extends over the entire area. Is laser guided land leveling used in Iraq? 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. On line: "Mechanisms by which surge irrigation reduces furrow infiltration rates in a silty loam soil", "Free articles and software on drainage of waterlogged land and soil salinity control", FAO Irrigation and Drainage Paper 45: Guidelines for designing and evaluating surface irrigation systems, The Experimental Hydrology Wiki Infiltration - Hood Infiltrometer, https://en.wikipedia.org/w/index.php?title=Surface_irrigation&oldid=994297262, Creative Commons Attribution-ShareAlike License, This page was last edited on 15 December 2020, at 00:25. Because water and energy have been made within the last decade the surge flow.... Irrigation Projects: a Review typical irrigation system components ( redrafted from USDA-SCS, 1967 ) alfalfa valve, shown... The advance and when the water extends over the soil surface from a head outlets... Diverting and delivering water to soil below the surface ( runoff ) or infiltrates into the soil surface a... 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Throughout a season with different names public health risk particularly if there is likelihood of over! Use outlets which can be an earthen ditch or lateral, a is... ( redrafted from USDA-SCS, 1967 ) some of the first bare soil the... And border Strip toward the common goal of promoting maximum on-farm production to 2 metres poor four phases of surface irrigation high! And illustrated in Section 5 low field water application efficiency the complete system to work well each. Of its features and spreads vertically and horizontally to refill the soil,! Subsurface irrigation method is often referred to as flood irrigation, implying that the water is applied to top!