Irrigation Engineering. Lecture Notes. Subject: Lining of Irrigation Channels. Lecturer: Imad Most of the irrigation channels in Iraq are earthen channels. The . that of the book “Irrigation Engineering”, significant additions and revisions have been Recent developments in Hydraulic Engineering related to Irrigation and. Download Irrigation Engineering And Hydraulic Structures By Santosh Kumar Garg – The book is designed to cover the major ﬁelds of agricultural and.
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It is not possible in a book of ordinary length, to go into all of the details essential to successful irrigation construction and operation. The broader and more. This book on "Irrigation Engineering" by. Prof. V. B. Priyani furnishes in concise, clearly intelligible language, illustrated by appropriate drawings or sket-. PDF | A plot of land growing a certain crop or a combination of crops has to be supplied with water from time to time. Primarily, the plot or field is.
The method is slow and in most places has been replaced by rotary drilling. It is a very simple method. Rigid boundary open channels 2. Optimum Consumptive Use: For construction of successful hydraulic structures. Notify me of new posts by email. With agricultural yields dwindling and demand for food increasing, the pressure on agriculture is immense and no stone is to be left unturned in meeting demands and expectations.
Open Chanel flow is that type of flow which is neither completely enclosed by the boundaries nor is under any external pressure but gravity. It is subjected to atmospheric pressure.
Rivers, natural and artificial canals, streams, channels etc. Partially filled pipes flow is also an example of open channel flow. Types of open channel flow Steady Flow: For open channel, the flow is steady if the depth of flow does not change with respect to time at a particular location or section.
Unsteady flow: For open channel, the flow is unsteady if the depth of flow changes with respect to time at a particular location or section. Uniform flow: For open channel flow, the flow is uniform if the depth of flow remains constant along a certain length of the channel. Non Uniform flow: For open channel flow, the flow is non uniform if the depth of flow does not remains constant along a certain length of the channel.
If the depth of flow changes over a relatively long distance along the length of a channel, then the flow is called gradually varied flow. Rapidly Varied flow: If the depth of flow changes over a relatively short distance along the length of a channel, then the flow is called rapidly varied flow.
Why to study open channel flow: For construction of successful hydraulic structures. Open channel flow is difficult to deal with because: Open channel flow can be said to be as the flow of fluid water over the deep hollow surface channel with the cover of atmosphere on the top. Examples of open channels flow are river, streams, flumes, sewers, ditches and lakes etc. While on the other hand flow under pressure is said to be as pipe flow e. Open-channel flow is usually categorized on the basis of steadiness.
Flow is said to be steady when the velocity at any point of observation does not change with time; if it changes from time to time, flow is said to be unsteady. At every instant, if the velocity is the same at all points along the channel, flow is said to be uniform; if it is not the same, flow is said to be non-uniform.
Non- uniform flow which is also steady is called as varied flow; non-uniform flow which is unsteady is called as variable flow. Flow occurs from a higher to a lower concentration by aid of gravity.
Shapes of open channels Usually the man made and artificial open channels don't have rectangular cross section. The most common shapes of open channels are circular and trapezoidal. Types of open channel Open Channels are classified as: Rigid boundary open channels 2.
Loose boundary open channels 3. Prismatic open channels Rigid boundary open channels can be said to be as the open channels with the non-changeable boundaries. While on the other hand if open channel has the boundaries which changes due to scouring action or deposition of sediments, such channels are said to be as loose boundary open channels. The open channels in which shape, size of cross section and slope of the bed remain constant are said to be as the prismatic channels.
Opposite o these channels are non-prismatic channels. Natural channels are the example of non-prismatic channels while man made open channels are the example of prismatic channels. Properties of Open Channels: The main difference in the open channel flow and pipe flow is that in pipe flow usually the cross section of channel is fixed and confined while on the other hand open channel flow is unconfined.
Open channels flow is difficult to analyze than the pipe flow. That's why in open channel flow measurement empirical approach is adopted. The velocity of flow in open channel can be computed by help of Manning's formula: There is no restriction for the conduit in case of open channel flow to be completely filled. Factors influencing the flow in open channels: Channel shape 2. Fluid depth 3. Fluid velocity 4. Slope of channel Flow measurement in open channel The most common method which is used for the measurement of flow in open channel is to measure the height of the liquid as it passes over an obstruction a flume or weir in the open channel.
This is usually done by constructing hydraulic structures like weirs, notches and flumes etc Manning approach can be used for flow measurement in open channels. The irrigation system in Pakistan has brought great benefits to many people.
Dependence on the natural hydrological system has been minimized and new settlements in canal irrigated areas have been established. However, the canal system has been accompanied by problems, which are increasingly difficult to overcome. Water logging and salinity are two of the outcomes of canal irrigation in Pakistan.
When only inundation canals were used, water for crops was only available during the summer season. A balance was maintained between the precipitation and evapo-transpiration that kept the water-table low. With the introduction of perennial canals, water was available throughout the year resulting in a rise of the water-table. Salts in the soil also rise to the surface with the water-table. The water on reaching the surface evaporates and the salts are deposited on the surface, rendering the land unsuitable for farming.
The rise of the water-table to the surface level is called water logging and the appearance of salty patches is called salinity. Management of Water Resources: Its storage, ibution and use have to be carefully managed in order me Water Accord was not followed resulting in disputes between the provinces and a decrease in the agricultural output. As Pakistan is predominancy an agricultural country, the scarcity of water resources may affect Pakistan's economy negatively.
Sites for small dams should be developed to store surplus flow during the monsoon season. Small dams are more cost effective and produce quick results compared with large dams because they are constructed in a shorter period of time are cheaper to build and easy to maintain. In order to avoid water loss from unlined canals, a crash program should be launched to line the canals with cement.
Fresh water sources like rivers and lakes should not be used as dumping sites of solid and liquid waste. Natural fresh water lakes should be conserved to develop local water sources. In Sindh, the Manchar, Kinjhar and Haleji lakes are the worst affected by pollution. Ground water contamination should be prevented as far as possible by controlling the seepage of toxic waste into the ground. A public education and information programme should be launched to influence the attitudes of the people towards the need to conserve water because it is a diminishing natural resource.
The media, NGOs and educational institutions should take part in this programme. Methods of Estimation of Consumptive Use of Water To measure or estimation the consumptive use there are three main methods: Empirical Methods 3. Pan evaporation method 1. Direct Methods: In this method field observations are made and physical model is used for this purpose. This includes, i. Field Plot Method iii. Tanks and Lysimeter iv.
Irrigation Method vi. Inflow Outflow Method 1. In this method of estimation of water consumptive use, soil moisture measurements are taken before and after each irrigation. The quantity of water extracted per day from soil is computed for each period. A curve is drawn by plotting the rate of use against time and from this curve, the seasonal use can be estimated. This method is suitable in those areas where soil is fairly uniform and ground water is deep enough so that it does not affect the fluctuations in the soil moisture within the root zone of the soil.
It is expressed in terms of volume i. Acre-feet or Hectare-meter 1. We select a representative plot of area and the accuracy depends upon the representativeness of plot cropping intensity, exposure etc.
It replicates the conditions of an actual sample field field plot. Less seepage should be there. Also some correction has to be applied for deep percolation as it cannot be ascertained in the field. In this method of measurement of consumptive use of water, a watertight tank of cylindrical shape having diameter 2m and depth about 3m is placed vertically on the ground. The tank is filled with sample of soil.
The bottom of the tank consists of a sand layer and a pan for collecting the surplus water. The plants grown in the Lysimeter should be the same as in the surrounding field. The consumptive use of water is estimated by measuring the amount of water required for the satisfactory growth of the plants within the tanks.
Methods 1 and 2 are the more reliable methods as compare to this method. In this method, it is necessary to know the division of total area, i. In this method, annual consumptive use for the whole area is found in terms of volume. It is expressed in Acre feet or Hectare meter. In this method, unit consumption is multiplied by some factor. The multiplication values depend upon the type of crops in certain area. This method requires an Engineer judgment as these factors are to be investigated by the Engineers of certain area.
In this method annual consumptive use is found for large areas.
If U is the valley consumptive use its value is given by, Empirical Methods: Empirical equations are given for the estimation of water requirement. These are, 2. It is a very simple method. Steps to design Precast Parabolic Channels The following steps are involved in the design of our selected water channel. A water well is a specially engineered hole in the ground; For ground water monitoring, or for scientific research purposes, wells may be drilled in a way that allows the specialists to closely examine the rock formations and take frequent water samples.
Augured wells and diamond core drilling are drilling techniques often used for scientific purposes. Most home wells are drilled to 8 or 6 inches in diameter. Municipal or irrigation wells are likely to be drilled at larger diameters, sometimes as much as 24 inches or more.
The important tasks for preparing a planning report of a water resources project would include the following: Analysis of basic data like maps, remote sensing images, geological data, hydrologic data, and requirement of water use data, etc.
Selection of alternative sites based on economic aspects generally, but keeping in mind environmental degradation aspects. Studies for local protective works — levees, riverbank revetment, etc. Formulation of optimal combination of structural and non-structural components for projects with flood control component. Economic and financial analyses, taking into account environmental degradation, if any, as a cost. Environmental and sociological impact assessment.
It is the quantity of water used by the vegetation growth of a given area.
It is the amount of water required by a crop for its vegetated growth to evapotranspiration and building of plant tissues plus evaporation from soils and intercepted precipitation. It is expressed in terms of depth of water. Consumptive use varies with temperature, humidity, wind speed, topography, sunlight hours, method of irrigation, moisture availability.
Factors Affecting the Consumptive Use of Water Evaporation which depends on humidity 2. Mean Monthly temperature 3. Growing season of crops and cropping pattern 4. Monthly precipitation in area 5. Wind velocity in locality 6. Soil and topography 7.
Irrigation practices and method of irrigation 8.
Optimum Consumptive Use 2. Potential Consumptive Use 3. Seasonal Consumptive Use 1. Optimum Consumptive Use: It is the consumptive use which produces a maximum crop yield.
Potential Consumptive Use: If sufficient moisture is always available to completely meet the needs of vegetation fully covering the entire area then resulting evapotranspiration is known as Potential Consumptive Use. Seasonal Consumptive Use: The total amount of water used in the evapo-transpiration by a cropped area during the entire growing season. A cross drainage work is a structure carrying the discharge from a natural stream across a canal intercepting the stream.
Canal comes across obstructions like rivers, natural drains and other canals. The various types of structures that are built to carry the canal water across the above mentioned obstructions or vice versa are called cross drainage works.
It is generally a very costly item and should be avoided by: Types of cross drainage works Depending upon levels and discharge, it may be of the following types: Cross drainage works carrying canal across the drainage: An Aqueduct 2.
Siphon Aqueduct Aqueduct: When the HFL of the drain is sufficiently below the bottom of the canal such that the drainage water flows freely under gravity, the structure is known as Aqueduct. In case of the siphon Aqueduct, the HFL of the drain is much higher above the canal bed, and water runs under siphonic action through the Aqueduct barrels.
The drain bed is generally depressed and provided with pucci floors, on the upstream side, the drainage bed may be joined to the pucca floor either by a vertical drop or by glacis of 3: The downstream rising slope should not be steeper than 5: When the canal is passed over the drain, the canal remains open for inspection throughout and the damage caused by flood is rare. However during heavy floods, the foundations are susceptible to scour or the waterway of drain may get choked due to debris, tress etc.
The structures that fall under this type are: This structure is suitable when the bed level of drainage is above the flood surface level of the canal. Thus, the canal water runs under the gravity. For economy, the canal may be flumed but the drainage trough is never flumed.
Type I: Sides of the aqueduct in earthen banks with complete earthen slopes. The length of culvert should be sufficient to accommodate both, water section of canal, as well as earthen banks of canal with aqueduct slope. Sides of the aqueduct in earthen banks, with other slopes supported by masonry wall. In this case, canal continues in its earthen section over the drainage but the outer slopes of the canal banks are replaced by retaining wall, reducing the length of drainage culvert.
Type II: Sides of the aqueduct made of concrete or masonry. Its earthen section of the canal is discontinued and canal water is carried in masonry or concrete trough, canal is generally flumed in this section. In view of growing population, urbanization and increased industrialization, the situation is likely to get worse.
In addition, increasing pollution and saltwater intrusion threaten the country's water resources. In urban areas, most water is supplied from groundwater except for the cities of Karachi, Hyderabad and a part of Islamabad, where mainly surface water is used. In most rural areas, groundwater is used. In rural areas with saline groundwater, irrigation canals serve as the main source of domestic water.
This shows the significance of agriculture in the country. Pakistan still has the world's largest Three reservoirs 2. More than , watercourses comprise the distribution network that takes water directly to the farms. The system commands a land area of Design Discharge cusecs No.
Flood level from floor ft Total Design Withdrawals for Canal cusecs Chashma 1,, 52 37 26, Guddu 1,, 64 26 - Jinnah , 42 28 7, Kotri , 44 Usually water requirement for crop is expressed in water depth per unit area.
This is based on both the temperature range of your climate and the amount of precipitation. Take a close look at the area in which you are going to plant your garden. If the ground tends to be very moist, choose plants that can tolerate constantly wet soil, and even standing water.
If you live in an area that suffers from frequent droughts, however, select plants that can tolerate going long periods without water, especially in light of the frequent watering restrictions imposed on such areas.
If you are lucky enough to live in an area that has a balanced climate, you have a wider range of choices for your plants. Low Water Requirement Plants Plants that require low levels of water are often called drought tolerant. Drought-tolerant plants can thrive in hot, dry conditions with very little water. They include both perennials and annuals.
Most drought-tolerant plants only have to be hand-watered when they are planted and while they are establishing themselves. After that, they can be left to the natural cycle of the elements. Popular All citrus trees are also drought tolerant.
Many homeowners in areas prone to drought, such as parts of the southern United States, use shrubs and ground covering vines as part of their landscaping. These include Texas sage, orange jasmine and Chinese fountain grass.
There are not many perennial drought-tolerant plants, but amaryllis is one that is very popular, along with the African iris. Popular drought-tolerant annuals include marigold, cosmos and the Dahlberg daisy. Mid-Level Water Requirement Crops Most plants land in this range when it comes to water requirements. These plants do not need to be watered every day, but they need to be watered when the soil has been dry for over a week or two.
Sometimes these plants are classified as plants lying in the "occasional water zone". These include popular plants such as geraniums, most roses, wisteria, clematis and other vine plants, sunflowers, spring flowering bulbs, and most flowering perennial shrubs.
Note that flowering annuals planted in containers will need watering at least once or twice a week, while annuals planted in the ground will need watering less often. High Water Requirement Plants Some plants require large amounts of water. These plants typically grow in marshy areas or bogs, or along the banks of rivers, streams and lakes. The soil for these plants should always be kept moist.
Standing water is not a concern for these plants, so you don't have to worry about root rot. Perennials are especially good for wet areas because they don't have to be replanted year after year, which can be difficult in marshy areas. Popular perennials for wet soil include iris plants, cannas, bee balms, ferns, and bog salvia. Aquatic mint is a pleasant ground cover that likes wet soil.
The red osier dogwood does very well in wet conditions.
Most annual flowering plants also do well in constantly moist soil. The amount of water taken by crops vary considerably. What crops use more water and which ones less Crop Water Requirement mm Rice Wheat Sorghum Maize Sugarcane Groundnut Cotton Soybean Tobacco Tomato Potato Onion Chillies Sunflower Castor Bean Cabbage Pea Banana Citrus Pineapple Gingelly Ragi Grape Irrigation Crop Water Requirement This case study shows how to calculate the total water requirement for a command area irrigation blocks under various crops, soil textures and conveyance loss conditions.
In order to evaluate the required irrigation gift for the entire command area a simple water balance has to be set-up. The total water demand for each irrigation block and the crops in each block are calculated by summing the following components: Evaluation of Percolation loss I The command area is divided in irrigation blocks. First, these irrigation blocks are crossed with the soil texture map to determine the area of each soil texture class in each block.
Percolation losses differ per soil texture class so a table with the following percolation data is created: The amount of water loss for each soil texture class per block is calculated with a tabcalc statement. In order to get the total percolation loss per block the results of the previous operation are aggregated. Evaluation of Conveyance loss S Conveyance losses are calculated in about the same way as the percolation losses.
First, the map with the irrigation blocks is crossedwith the channel distribution map. The conveyance loss per meter channel length differs per channel type and is 0.
A new table indicating water loss per channel type is created and joined to the cross table. The amount of water loss for each type of channel per block is calculated with a simple tabcalc formula. Finally the results are aggregated to evaluate the total conveyance loss per irrigation block. Evaluation of maximum evapo-transpiration ETm Crop water requirements are normally expressed by the rate of evapotranspiration ET.
The evaporative demand can be expressed as the reference crop evapotranspiration ETo which predicts the effect of climate on the level of crop evapotranspiration. Empirically-determined crop coefficients kc can be used to relate ETo to maximum crop evapotranspiration ETm when water supply fully meets the water requirement of the crop.
The value of kc varies with crop and development stage. The kc values for each crop and development stage are available in a table. Maximum evapotranspiration is calculated in this case study by crossing the irrigation block map with the map that shows the different crop types in the command area, joining the cross table with the kc table and by applying the maximum evapotranspiration formula with a tabcalc statement.
The total amount of water requirement in harvest period for each block is reclassified in irrigation classes using the following table: Upper boundary Irrigation class 1 2 3 4 5 6 Finally, you will create a script to automate the calculation procedure.
With the script, you can easily calculate the water requirements for other growing stages. Increase in Crop Yield 2. Protection from famine 3. Cultivation of superior crops 4. Elimination of mixed cropping: Economic development 6. Hydro power generation 7. Domestic and industrial water supply: The data set is made up of temperature time series, obtained from gauging stations. The potential evapotranspiration estimated for each station using the above-mentioned methods is spatially integrated, in order to obtain the areal potential evapo-transpiration.
The methods adopted for the spatial integration of the point estimates are the Kriging method, the method of Inverse Distance Weighting, the Spline method and the Thiessen method, using applications in a Geographic Information System GIS with a spatial resolution of xm2.
Tmin T? Pressurized distribution 2. Gravity flow distribution 3. Drainage flow distribution. Pressurized Distribution The pressurized systems include sprinkler, trickle, and the array of similar systems in which water is conveyed to and distributed over the farmland through pressurized pipe networks. There are many individual system configurations identified by unique features centre-pivot sprinkler systems. Gravity Flow Irrigation System Gravity flow systems convey and distribute water at the field level by a free surface, overland flow regime.
These surface irrigation methods are also subdivided according to configuration and operational characteristics. Control of drainage flow irrigation System Irrigation by control of the drainage system, sub-irrigation, is not common but is interesting conceptually.
Relatively large volumes of applied irrigation water percolate through the root zone and become a drainage or groundwater flow. By controlling the flow at critical points, it is possible to raise the level of the groundwater to within reach of the crop roots.
These individual irrigation systems have a variety of advantages and particular applications. Irrigation systems are often designed to maximize efficiencies and minimize labour and capital requirements. The most effective management practices are dependent on the type of irrigation system and its design. For example, management can be influenced by the use of automation, the control of or the capture and reuse of runoff, field soil and topographical variations and the existence and location of flow measurement and water control structures.
Questions that are common to all irrigation systems are when to irrigate, how much to apply, and can the efficiency be improved. A large number of considerations must be taken into account in the selection of an irrigation system. These will vary from location to location, crop to crop, year to year, and farmer to farmer. Compatibility of the irrigation systems: The irrigation system for a field or a farm must be compatible with the other existing farm operations, such as land preparation, cultivation, and harvest.
Gravity irrigation methods are less expensive, but requires more skill and experience to achieve re-scannable efficiency. This method also requires that the land to be irrigated should have a flatter slope, other wise the cost of land leveling and preparation at times be come very high. Gravity irrigation method. Includes furrow, boarder, basin, wild- flooding and corrugation. Furrow irrigation In this method of surface irrigation, water is applied to the field by furrow which are small canals having a continuous our nearly uniform slope in the direction of irrigation.
Water flowing in the furrow into the soil spreads laterally to irrigate the area between furrows. The rate of lateral spread of water in the soil depends on soil type. For a given time, water will infiltrate more vertically and less laterally in relatively sandy soils than in clay soil.
When field sloped is too steep to align the furrows down the slope, control furrows which run along curved routed may be used. Spacing of furrows depends on the crop type and the type of machinery used for cultivation and planting.
Length of furrows depends largely on permeability of the soil, the available labor and skill, and experiences of the irrigation. Flow rates are related to the infiltration to the rate of the soil. Longitudinal slope of furrow depends up on the soil type, especially its errodability and the velocity of flow.
Slope may be related to discharge as follows. Boarder - strip Irrigation The farms are divided into number of strips of 5 to 20 meters wide and to meters long. Parallel earth bunds or levees are provided in order to guide the advancing sheet of water. Recommended safe limits of longitudinal slope also depends on the soil texture: Sandy loam to sandy soils 0. Basin irrigation Large stream of water is applied to almost level and smaller unit of fields which are surrounded by levees or bunds.
The applied water is retained in the basin until it filtrates. Soil type, stream size and irrigation depth are the important factors in determining the basin area. Wild flooding Water is applied all over the field especially, before plowing for soil that can't be plowed when dry. Under closed conduit- there are two types of irrigation 1. Sprinkler 2. Drip irrigation Sprinkler irrigation: It is mostly used for young growth, to humid the atmosphere, for soil compaction specially for sandy loam soils before planting, for land having up and down slope and used to wash out plant leaves especially in dusty area.
Sprinkler irrigation offers a means of irrigating areas which are so irregular that they prevent use of any surface irrigation methods.
By using a low supply rate, deep percolation or surface runoff and erosion can be minimized. Offsetting these advantages is the relatively high cost of the sprinkling equipment and the permanent installations necessary to supply water to the sprinkler lines. Very low delivery rates may also result in fairly high evaporation from the spray and the wetted vegetation. Drip irrigation This is used especially where there is shortage of water and salt problem. The drip method of irrigation, also called trickle irrigation.
The method is one of the most recent developments in irrigation. It involves slow and frequent application of water to the plant root zone and enables the application of water and fertilizer at optimum rates to the root system. It minimizes the loss of water by deep percolation below the root zone or by evaporation from the soil surface. Drip irrigation is not only economical in water use but also gives higher yields with poor quality water.
Choice and Selection of Irrigation Methods Following are some reasons and factors which affect the selection of an irrigation system for a specific area: Compatibility of the irrigation system 2. Topographical characteristics of area 3.
Economics and cost of the irrigation method 4. Soils Water supply 6. Crops to be irrigated 7. Social influences on the selection of irrigation method 8. External influences 1. Compatibility of the irrigation system The irrigation system for a field or a farm must be compatible with the other existing farm operations, such as land preparation, cultivation, and harvest.
The irrigation systems must not interfere with these operations and may need to be portable or function primarily outside the crop boundaries i. Smaller equipment or animal-powered cultivating equipment is more suitable for small fields and more permanent irrigation facilities. Topographical characteristics of area Topography is a major factor affecting irrigation, particularly surface irrigation. Of general concern are the location and elevation of the water supply relative to the field boundaries, the area and configuration of the fields, and access by roads, utility lines gas, electricity, water, etc.
Field slope and its uniformity are two of the most important topographical factors. Surface systems, for instance, require uniform grades in the percent range. Restrictions on irrigation system selection due to topography include: Economics and cost of the irrigation method The type of irrigation system selected is an important economic decision. Some types of pressurized systems have high capital and operating costs but may utilize minimal labour and conserve water.
Their use tends toward high value cropping patterns. Other systems are relatively less expensive to construct and operate but have high labour requirements. Some systems are limited by the type of soil or the topography found on a field. The costs of maintenance and expected life of the rehabilitation along with an array of annual costs like energy, water, depreciation, land preparation, maintenance, labour and taxes should be included in the selection of an irrigation system.
Main costs include: Soils The soil's moisture-holding capacity, intake rate and depth are the principal criteria affecting the type of system selected. Sandy soils typically have high intake rates and low soil moisture storage capacities and may require an entirely different irrigation strategy than the deep clay soil with low infiltration rates but high moisture-storage capacities.
Sandy soil requires more frequent, smaller applications of water whereas clay soils can be irrigated less frequently and to a larger depth. Other important soil properties influence the type of irrigation system to use. The physical, biological and chemical interactions of soil and water influence the hydraulic characteristics and filth.
The mix of silt in a soil influences crusting and erodibility and should be considered in each design. The soil influences crusting and erodibility and should be considered The distribution of soils may vary widely over a field and may be an important limitation on some methods of applying irrigation water. The soil type usually defines: Water supply The quality and quantity of the source of water can have a significant impact on the irrigation practices.
Crop water demands are continuous during the growing season. The soil moisture reservoir transforms this continuous demand into a periodic one which the irrigation system can service.
A water supply with a relatively small discharge is best utilized in an irrigation system which incorporates frequent applications. The depths applied per irrigation would tend to be smaller under these systems than under systems having a large discharge which is available less frequently.
The quality of water affects decisions similarly. Salinity is generally the most significant problem but other elements like boron or selenium can be important.
A poor quality water supply must be utilized more frequently and in larger amounts than one of good quality. Crops to be irrigated The yields of many crops may be as much affected by how water is applied as the quantity delivered. Irrigation systems create different environmental conditions such as humidity, temperature, and soil aeration.
They affect the plant differently by wetting different parts of the plant thereby introducing various undesirable consequences like leaf burn, fruit spotting and deformation, crown rot, etc. Rice, on the other hand, thrives under ponded conditions. Some crops have high economic value and allow the application of more capital-intensive practices, these are called "cash crops" or Cash crop farming.
Deep-rooted crops are more amenable to low-frequency, high-application rate systems than shallow-rooted crops. Cash Crop Water Requirement Crop characteristics that influence the choice of irrigation system are: Social influences on the selection of irrigation method Beyond the confines of the individual field, irrigation is a community enterprise.
Individuals, groups of individuals, and often the state must join together to construct, operate and maintain the irrigation system as a whole. Within a typical irrigation system there are three levels of community organization. There is the individual or small informal group of individuals participating in the system at the field and tertiary level of conveyance and distribution. There are the farmer collectives which form in structures as simple as informal organizations or as complex as irrigation districts.
These assume, in addition to operation and maintenance, responsibility for allocation and conflict resolution. And then there is the state organization responsible for the water distribution and use at the project level. Irrigation system designers should be aware that perhaps the most important goal of the irrigation community at all levels is the assurance of equity among its members. Thus the operation, if not always the structure, of the irrigation system will tend to mirror the community view of sharing and allocation.
Irrigation often means a technological intervention in the agricultural system even if irrigation has been practiced locally for generations. New technologies mean new operation and maintenance practices. If the community is not sufficiently adaptable to change, some irrigation systems will not succeed. External influences Conditions outside the sphere of agriculture affect and even dictate the type of system selected. For example, national policies regarding foreign exchange, strengthening specific sectors of the local economy, or sufficiency in particular industries may lead to specific irrigation systems being utilized.
Key components in the manufacture or importation of system elements may not be available or cannot be efficiently serviced.
Since many irrigation projects are financed by outside donors and lenders, specific system configurations may be precluded because of international policies and attitudes. Strainer type 2. Cavity type 3. Slotted type Design of strainer or well screen for Tube Wells In design, find its length, slot size, opening area, diameter and material requirements a. Corrosion resistant b. Strong enough to prevent collapse c. Prevent excessive movement of sand into well d.
Minimum resistance to flow of water into the well Materials used for Tube Well Construction 1. Zinc free brass Stainless steel 3.
Low carbon steel 4. Chapter-1 To discuss about the Students will learn the importance of Irrigation importance of Irrigation and irrigation engineering engineering To discuss about the Students will learn the importance of Irrigation importance of Irrigation and irrigation engineering engineering To discuss Advantages and Disadvantage of irrigation ill effects To discuss Advantages and Disadvantage of irrigation ill effects Students will learn Advantages and Disadvantage of irrigation ill effects Students will learn Advantages and Disadvantage of irrigation ill effects ppt Lecture 2 T Chapter-1 RW-1 Lecture 3 T Chapter-1 RW-1 ppt Lecture 5 T Chapter-1 RW-3 Types of irrigation Students will learn ypes project purpose wise and of irrigation project administrative wise Lecture 6 T Chapter-1 RW-3 Types of irrigation Students will learn ypes project purpose wise and of irrigation project administrative wise.
Lecture Description Relevant Websites. Audio Visual Aids. Chapter-2 RW-2 Lecture 9 T Chapter-3 RW-4 Lecture 14 T Chapter-3 RW-3 Lecture 15 R Chapter-2 RW-5 Lecture 18 R Chapter-2 RW-5 To discuss about Types of rain gauge Students will learn how ppt the rain fall measured.
Chapter-2 RW-6 R Chapter RW-8 To discuss about Dam Types of dams Earthen dams and Gravity dams To discuss about Dam Types of dams Earthen dams and Gravity dams Comparison of earthen and Gravity dams with respect to foundation seepage construction and maintenance Earthen Dams Comparison of earthen and Gravity dams with respect to foundation seepage construction and maintenance Earthen Dams Test 2 DAMS Seepage through embankment and foundation Seepage control through embankment and foundation Methods of constructions DAMS Types of failure of earthen dams and remedial measures Gravity Dams Theoretical and practical profile Drainage gallery joint in gravity dam high dam and low dam T Chapter RW-9 To find Seepage through embankment and foundation Seepage control Types of failure of earthen dams and remedial measures Gravity Dams Theoretical and practical profile Drainage Students will learn What are the main causes of failure of embankment Students will learn Types of failure of earthen dams and remedial measures Students will learn different types of dam ppt Lecture 23 T Chapter and Gravity dams with respect to 20 foundation seepage construction and maintenance Earthen Dams Components and their function Typical cross section RW-9 Students will learn ppt Comparison of earthen and Gravity dams with respect to foundation seepage Students will learn ppt Comparison of earthen and Gravity dams with respect to foundation seepage Week 9 Lecture 25 RW-9 Lecture 26 Lecture 27 Week 10 Lecture 28 T Chapter RW Chapter-2 RW-6 Run off.
Chapter RW to learn about spillway function location and components Types of spillway ogee spillway Students will learn spillway function location and components ppt Lecture 30 T Chapter-9 RW To discuss about Spillway and their typesWeirs components parts Functions and types Layout of diversion head works with its components To discuss the importance of Barrages Components and their function Difference between weir and barrage irrigation Test 3 Students will learn about the Weirs components parts Functions and types Layout of diversion head works with its components Students will learn Barrages Components and their function Difference between weir and barrage T Chapter RW To discuss the important of CD works Different types of CD works canal falls Escapes cross regulators Importance of canal Classification of canals according to alignment and position in the canal network Importance of canal Classification of canals according to alignment and position in the canal network Students will learn ppt what are the role of CD works Different types of CD works canal falls Escapes Students will learn ppt about diff rents types canal Classification of canals according to alignment and position in the canal network Students will learn ppt about diff rents types canal Classification of canals according to alignment and position in the canal network Lecture 35 T Chapter-8 RW Lecture 36 T Chapter-5 RW Lining of canal Students will learn Definition purpose types Lining of canal of canal lining Definition purpose types of canal lining.
Chapter RW Contingency Lecture 39 To discuss about the importance Factors affecting siling Methods to control levels Lining properties of good canal lining material Students will learn what is the importance of Survey for irrigation project data collected for irrigation Week 14 Lecture 40 T Chapter RW-1 Lecture 42 T Component Test Frequency 2 Total: Types of irrigation project purpose wise and administrative wise Methods of Irrigation.
Advantages and Disadvantage of irrigation ill effects of over irrigation. AT No. To know about the different techniques of irrigation and crop seasons in different area. Introduction of canal Classification of canals according to alignment and position in the canal network Design of most economical canal section.
Survey for irrigation project data collected for irrigation project Area capacity curve Silting of Reservoir Rate of sling. Seepage through embankment and foundation Seepage control through embankment and foundation Methods of constructions. D works canal falls Escapes Individual cross regulators and canal outlets. Student will learn how to control flow of river and network for effective disposal of water.
Types of rain gauges names only Average annual Rain fall and its calculation C. Flag for inappropriate content.