Aqua 105 - Aquaculture Engineering Lecture Notes PDF

PAMPANGA STATE AGRICULTURAL UNIVERSITY MAGALANG, PAMPANGA LECTURE MANUAL ON AQUA 105 – AQUACULTURE ENGINEERING BY: MR. DANTE M. MENDOZA Instructor I – MS AQUA S.Y. 2015-2016 ...

PAMPANGA STATE AGRICULTURAL UNIVERSITY MAGALANG, PAMPANGA LECTURE MANUAL ON AQUA 105 – AQUACULTURE ENGINEERING BY: MR. DANTE M. MENDOZA Instructor I – MS AQUA S.Y. 2015-2016  UNIT I INTRODUCTION TO AQUACULTURE ENGINEERING Unit Objectives This unit aims to: 1. Define aquaculture engineering and explore the areas covered by the discipline; 2. Discuss the status of aquaculture engineering in the country and in neighboring countries; 3. Identify the latest developments in the field of aquaculture engineering; 4. Explain the potentials of aquaculture in the region of Southeast Asia and how the discipline of engineering can be integrated; 5. Identify issues and problems that affect aquaculture production and determine engineering concepts that could mitigate or eliminate these problems; Introduction In a recent comprehensive review of world aquaculture, it was reported that carp and tilapia production represents about 46% of the total world aquacultural production on a weight basis, salmon and trout 4%, shrimp and prawn 2.2%, oysters and mussels 37%, and catfish 2.2%. It was also reported that freshwater production accounts for 80% to 90% of the world’s finfish production, 95% of which in ponds. Cage vulture represents only 3% to 4% of freshwater finfish production, but about 40% of marine and brackishwater finfish production. 1.1. Definition Aquaculture Engineering is defined as the application of sound engineering principles (chemical, civil, mechanical, and electrical) to create a suitable condition or environment for optimum growth of aquatic species being produced. It also applies knowledge of economics, chemistry, and fisheries – biology, health management, post-harvest and processing, and marketing. A discipline dealing with the application of the fused biological and civil engineering principles in the planning and execution of fishery works in order to create the best environment for the cultured species (E. Vera Cruz). Fishpond Engineering is the science of planning, designing and constructing ponds including water control structures. Fishpond Engineering takes into consideration most especially the physical structures and economy of construction based on the proper engineering procedure and application (FAO). 1.2. Status of Aquaculture Engineering Aquaculture engineering in the Philippines started when poor or inadequate engineering was recognized as one of the primary reasons for the country’s low fish production. It has since developed rapidly and recognized as the sector that could address the production shortfall from capture fisheries. In fact in 2004, aquaculture accounted for about 42% of the country’s total fisheries production. Some 413,484 hectares of coastal fishponds are located mainly in the Philippines. Indonesia, Thailand, Vietman, Malaysia, Taiwan (China). Hong Kong and Singapore. They are used for raising finfish, mainly milkfish such as in Indonesia, Philippines and Taiwan or penaid shrimps such as in Thailand, Singapore and Malaysia. At present, polyculture of milkfish and penacid shrimps and stocking of sea-bass are fast developing (dela Cruz, ) According to Dela cruz, the development of this industry at the beginning can be attributed primarily on private sector initiative. Based on very crude facilities and simple rural experience, the production has been generally low, at present about 670 kg/ha/year on the average in the whole region, although ranges from as low as 300 kg/ha to as high as 2 000 kg/ha (e.g., Taiwan) occur. The value of production from this industry is evaluated at over US$350 million per year, which can be a big boost to the economy of the region. Prices has been relatively low for milkfish (average US$1/kg) but rather high for penaeid shrimps (US$3-8 kg) and also good for seabass (US$3-5/kg). 1.3 Potentials The potentials for the further development of this industry in the region of Southeast Asia is high. There are still large acreage of mangrove swamps and tidal mudflats that can be suitable sites for development into fishponds, estimated at about 5½ million hectares in the Southeast Asian countries. Some 10 to 30 percent of the existing swamps can be developed, such a ratio being deemed feasible and affords proper ecological considerations, the area that can be developed in the region can be about 0.5 to 1.6 million hectares. Average production can be increased to double the yield with better engineering and the use of improved technology of management in the existing areas. 1.4 Major engineering problems Poor or inadequate engineering of aquaculture units is one of the major causes of low production and/or failure. Such engineering deficiencies can be classified into three categories, viz. (i) problems brought about by climatic and hydrological factors: (ii) problems due to environmental factors; and (iii) engineering specific problems. 1.3.1 Problems due to climate and hydrology The type of rainfall, occurrence of typhoons, and prevailing tidal charcteristics in the fishpond location can influence the nature of construction of fishponds in such area. Where rains are strong and severe and where typhoons are frequent, the fishpond structures need to be bigger and more firm. Likewise, areas with high tidal ranges (average daily range of 3 m or more) will require bigger dikes and sturdy water control structures, whereas areas where the tidal fluctuation is small (one meter or less daily range), the dikes can be smaller and water gates need not be massive. Areas prone to earthquakes and tidal waves should likewise make some extra provision for these occurrences. 1.3.2 Environmental influences The engineering of coastal fishponds can be affected by various environmental influences. These include such factors as the nature of the soil, vegetation, elevation of site, topographic characteristics, availability of freshwater supply and occurrence of pollution. If the site has porous type soil (sandy or peaty), bigger dikes need to be provided. In some cases, better clayey soil for diking may have to be brought from outside. Well vegetated areas especially with big-size trees will require bigger construction effort. Elevation of the site based on the tidal datum will determine whether excavation or filling will be required, while those with uneven topography will need more work in levelling the area. It is better to have some source of freshwater supply for coastal fishponds so that the brackishwater salinity which is usually more suitable for growing food organisms as well as the cultured species can be maintained. If however this is not available, the fishpond should be so engineered so that the periodic occurrence of freshwater such as from rains can be taken advantage of.  Freshwater supply from the tidal river or stream is usually the cheapest source of freshwater as this can be taken in by gravity. However, this may not be available so that other sources have to be determined and tapped. The seasonal rains can be another source, although this can be seasonal and not very reliable. Underground water is another source of this, if available. Sometimes the pond bottom is low enough in relation to the water table so that underground water can seep in naturally to the ponds. Piped water through wells of varying depths is good, if this is available. All the above sources of freshwater will need engineering structures so that the required water can be put into use. Pumps, either to draw in or drain out excess water, may be found necessary and helpful. Occurrence of pollution is a difficult problem in coastal fishpond areas and should be avoided if this was noted before the farm is established. However, if this condition should happen after the fishpond has been constructed; additional structures may need to be installed to minimize the effects of this adverse factor. 1.3.3 Engineering specific problems These are the site specific problems that are encountered during actual construction or after the construction of the fishpond. For instance, after the fishpond has been constructed, there is a need to shift the kind of management from the traditional extensive method to the modular progression method or to the stock manipulation method: this will require a renovation of the layout of the fishpond system. Again, if the fishpond is to shift from milkfish monoculture to milkfish shrimp polyculture or to shrimp monoculture, some definite pond modifications have to be made for such a shift. During the construction, it sometimes occur that there is excess soil that needs to be disposed of properly, or there may be lack of soil that can be adequate for the needed diking or filling work. These have to be solved through engineering means. Many engineering problems occur with regard to the water control structures. These have to be properly designed and well-constructed and located in appropriate places in relation to the entire fishpond system. These structures are usually expensive to put up and once made they are very difficult to change. It is noted however, that some progress have been attained in better designs and in the method of constructing these water control structures. More lasting materials like fiberglass, ferrocement, etc., especially if these can be prefabricated may lessen the inherent costs encountered with these fishpond structures. Correcting water leakages and seepages in finished fishponds often present many problems. Even if these have to be dealt with on a case to case basis, there is need for aquaculture engineers to develop and improve the technology involving these very frequent problems in coastal fishponds. Source: C.R. Dela Cruz. Fishpond engineering: a technical manual for small-and medium-scale coastal fish farms in southeast Asia. SEAFDEC. Fisheres Statistical Bulletin for the South China Sea Area. 1978 (1980).  UNIT II AQUACULTURE FACILITIES OR SYSTEMS Unit Objectives This unit aims to: 1. Present the different facilities or systems that are used for aquaculture purposes: hatchery production, grow-out production, and ornamental culture purposes; 2. Differentiate and describe one culture facility/system from the others; 3. Discuss the place or condition of the place to where one facility/system is best fitted or suited for use. Aquacultural Systems An aquacultural production system can be described simply as production of marketable aquatic organisms under controlled or semicontrolled conditions. Aquacultural systems are classified in a variety of ways depending upon the viewer’s perspective and interest. 1. Land-Based Systems: Ponds, Tanks, Raceways, Recirculating Systems Pond – It is an enclosed body of water with or without inlets and outlets known as gates. – It is a shallow body of standing water (lentic environment) and is usually smaller than lake. – It is a shallow lake. – It is a man-made or naturally formed structure although the former classification is more existing. Two Primary Types of Pond (both for saltwater, brackishwater and freshwater areas) 1. Embankment ponds – are formed by building-up a dam or dike to impound water 2. Excavated ponds – are formed by excavating soil from areas to form depressions or holes and filling them with water to form ponds – Cost of development in embankment ponds is lower than in the excavated ponds. Types of Pond (for freshwater areas only) 1. Barrage ponds – are those usually filled by rainfalls or spring water. These require overflow pipes and overflow channels. 2. Diversion ponds – are made by diverting (bringing) water from another source, like a steam or a river. A channel or canal is dug to carry the water from the water source to the pond. Tanks – Concrete Tanks – Wooden Tanks – Fiberglass Tanks – Canvass Tanks – Plastic Tanks – Glass Tanks Raceways – Raceways, also called flow-thru systems, are culture systems in which water flows continuously, making a single pass through the unit. – They are constructed from concrete or cement blocks, or fabricated from wood, fiberglass, metal and plastic materials; or they can be earthen raceways. – If the land is sloping, a series of raceways can be constructed, linked to each other end to end, one unit flowing into the other, and separated by filters. Oxygen is added to the water by the splashing action as water exits one cell and drops into the other. – In fish culture, traditional raceways are enclosed channel systems with relatively high rates of moving or flowing water. This high rate of water movement gives raceway systems distinct advantages over the other culture systems. Advantages of raceways include: Disadvantages include: - Higher stocking densities - Reliance on electricity or fuel for water flow - Improved water quality - Risk of fish mortality due to disease or water quality problems  - Reduced manpower - High level of technology required - Ease of feeding, grading and harvesting - Precise disease treatments - Collection of fish wastes - Less off-flavour Recirculating Systems – In a recirculating system, the same water is reused, after appropriate physical, biological or chemical purification. – Fisheries researchers have used recirculating systems for holding and growing fish for more than three decades. Attempts to advance these systems to commercial scale food fish production have increased dramatically in the last decade. Advantages of raceways include: - Does not require large quantities of land and water. - A high degree of environmental control - Can be carried out close to market areas Disadvantages include: - Needs a lot of complicated machinery, which can be difficult to maintain - Biologically complex - Increased risk of poor water quality - Greater risk of stress and diseases - Common incidence of off-flavor are common - High levels of technical expertise required - High cost 2. Water-Based Systems: Fishpen and Fishcage Fishpen – It is a man-made structure constructed from wooden or metal poles as posts; frames and braces; and from nettings, plastic materials or woven bamboo slats (banata) as sidings or enclosures. – The bottom of the structure of which is formed by the bed or floor of the water body (sea bed, lake bed, river bed). – It tends to be larger in size than cage, ranging from 0.1 ha (1000 m2) to several hectares. – It is built in a rectangular, square or circular shape. – It is installed in not more (>) than 8 meters depth. Fishcage – It is a man-made structure constructed from materials like that of a fishpen and is enclosed at the sides, at the bottom and maybe on the top. – It is smaller in size than pen and typically has a surface area between 1 m2 – 1000 m2. – It is constructed in rectangular, square or circular shape. Four Types of Cage 1. Floating cage – is a cage whose mesh bag is supported by a buoyant collar frame. – It is set in not less than 3 meters depth. 2. Fixed cage – is a cage whose mesh bag is supported by posts driven into the substrate (bottom soil).  – It is set in shallow areas not more than 8 meters depth. 3. Submersible cage – is a cage that could be a fixed or a floating cage. It could be set above or 1 m below the water surface. This cage is used primarily in places prone to storms. 4. Submerged cage – is a cage set below the water surface or at the floor of the water body.  UNIT II SELECTION AND EVALUATION OF FISHPOND/FISHPEN/CAGE SITE Unit Objectives This unit aims to: 6. Discuss the different major and minor factors to be considered in site selection for fishpond, fishpen/fishcage purposes; 7. Characterize the water, soils, topography and other factors considered best for fishpond purposes; 8. Identify kinds and types of soils in the mangrove areas and the upland areas alike; 9. Identify the trees and other plant life in the mangrove areas which indicate the physical and chemical properties of soil good and not beneficial for fishpond purposes; 10. Analyze the water condition of the surveyed site; 11. Explain the causes of tidal fluctuation or rise and fall of water as one factor considered in site selection; 12. Discuss the tidal characteristics and the ground elevation; 13. Illustrate and demonstrate the method of determining the zero datum [or known as the mean low water (MLW) or mean lower low water (MLLW)] – the water level at which the pond floor to be constructed is based upon. A. Factors To Consider in Selecting Fishpond Site 1. Water supply 4. Topography 2. Tidal characteristics 5. Vegetation and ground elevation 6. Climatic condition 3. Soil 7. Other factors 1. Water Supply – It is the first and most important factor to consider. – It should be clean (free from pollutants) and available throughout the year. – For brackishwater aquaculture, the seawater and the freshwater should be available the whole year round. – Water in the river supplied into the pond through gravitational force is economical but may not be good for use. – Underground water supplied by the use of giant pump is clean but may not be economical yet may pose danger of intrusion of seawater into the freshwater aquifer affecting the domestic users of freshwaters. – It should be well oxygenated. – It should contain adequate nutrients essential for growth of algae and other desirable aquatic plants. – Water temperature and salinity should suit the requirement of fish under cultivation. 2. Tidal Characteristics and Ground Elevations ( see Appendix A). – The suitability of a site for brackishwater pond depends upon the tidal characteristics of the area and its ground elevation. – In some areas, there are only one high and one low tide that come in 24-hour period. – In other areas, high tide and low tide come twice in a day. – Areas whose ground elevation is reached only by the highest spring tide is not suitable for brackishwater fishpond. – Low lying areas whose floor elevation is under water during or on level with the lowest low tide is, likewise, not suitable. – Ideal elevation is when the site can be filled with tidal water to the desired depth within 5 days during the critical spring tides which occur in February, March and April and is when the site can be drained almost any day. – 20 cm above the datum plane (zero datum or mean lower low water, MLLW) is considered a good ground elevation for brackishwater pond. – Or a depth of at least 50 - 60 cm that can be maintained above the floor of the site is also good for brackishwater pond. Definition of Tidal Terms Tide – refers to the regular rising and falling of the seawater level in response to the gravitational attraction of the moon and the sun. Tidal current – is the movement of seawater towards the shore and towards the sea. It is also defined as the periodic horizontal flow of water resulting from the rise and fall of the tides. Tidal range – refers to the difference between the mean higher high water (HHW) and the mean lower low water (LLW) in a mixed tide. In diurnal and semi-diurnal tides, it is the difference between the highest water and the lowest water. Tide period – is the time interval between two successive high waters.  Spring tides – are tidal waters of greater amplitudes which means that the high waters are much higher and the low waters are much lower than usual. These occur when the sun, the moon, and the earth are in a straight line. They are associated with new moons and full moons, and therefore they occur twice a month. Neap tides – are tidal waters of smaller amplitudes. The high waters during neap tides are lower than those observed in spring tides and the low water are higher than those observed in spring tides. These are produced when the moon and the sun form the extremes of a right triangle. These occur during the first and the last quarter phases of the moon. Flood tide – refers to the incoming or rising tide. Ebb tide - refers to the drawing back of tidal water from the shore or to the outgoing or falling tide. Diurnal tide – is a type of tide having only one high and one low water per tidal day (Appendix B). Semi-diurnal tide – is a type of tide where high and low water occur twice a day or is a tide which has a cycle of about one-half a tidal day (Appendix B). Mixed tides – is a type of tide characterized by having a large inequalities of either the high or the low water heights with two high waters and two low waters per tidal day (Appendix B). Diurnal equality – refers to the differences in height of the two high water or of the two low water of each day. MHHW – is the acronym for mean higher high water. In a mixed tide, there are two high tides occurring in a 24-hour period. One high tide is the lower high water and the other is the higher high water, the latter of which is used as the basis for determining the tidal range. MLLW – is the acronym for the mean lower low water. In a mixed tide, there are also two low tides within a whole day: the lower low water and the higher low water, the former of which is also a factor in tidal range determination. As to pond construction, MLLW is usually the zero datum or datum plane, or a reference point from which the ground elevation of the pond site is determined. MLLW is the average of all lower low waters. 3. Soils – Soil is an important factor in pond productivity due to its ability to adsorb and release the essential nutrients required by plants. – It serves as the chief and most economical source of materials for building dikes. Two Categories of Soil 1. Inorganic soils – which include clay, silt and sand among others, and those soils with moderate organic matter contents. 2. Organic soils – which include those soils with high organic matter contents; which have high shrinkage; and whose colors range from brown to black. * Two Classifications of Organic Soil 1. Muck soil – consists of thoroughly decomposed organic materials with considerable amounts of finer mineral soil finely divided with some fibrous remains. 2. Peat soil – consists of a dense accumulation of partially decayed fibrous materials. Soil Texture. This refers to the relative proportion of sand, silt and clay in the soil (Appendix B & C). General Classification of Soil 1. Sand – a coarse soil whose size ranges 0.05 - 2 mm in and which feels gritty when rubbed between the fingers.  2. Silt – a moderately fine soil whose size ranges 0.002 - 0.04 mm in and which feels smooth and powdery and not sticky when moist. 3. Clay – a fine soil whose size is < 0.002 mm in and which feels smooth, sticky and plastic when moist; it forms very hard clod when dry. * Soil predominantly composed of hard particles having of > 2 mm is gravelly or stony. The Three Main Types of Soil (Appendix C) Common Name Texture Basic soil textural class name Sandy soils Coarse Sandy, sandy loam Moderately coarse Fine, sandy loam Loamy soils Medium Very fine sandy loam Moderately fine Loam, silty loam, silt Clayey soils Fine Clay, silty clay, sandy clay, clay loam, silty clay loam, sandy clay loam * Loam – has an equal proportions of sand, silt and clay. It is mellow with somewhat a gritty feel, yet fairly smooth and slightly plastic. The following textural class of soils are preferred for fishpond purposes due to their superiority in water-holding capacity and nutrient contents and as diking materials, to wit: 1. clay 5. silty clay loam 2. silty clay 6. sandy clay loam 3. sandy clay 7. loam 4. clay loam * Of the 7 textural classes, clay loam and sandy clay loam are the best because of their clay components which are excellent water holder and diking materials and of their loam components which contain high organic matter necessary for growth algae. 4. Topography This refers to the surface feature or lay of the land, or the changes in the surface whether flat, undulating (wavy), hilly, sloping or rolling. – The best topography for fishpond is flat or slightly sloping toward the outlet. – More significant in brackishwater than freshwater pond farm – A slope of 2% is ideal. Four zones in the coastal edge which are probable sites for fishpond (Fig.1) – Zone A: marginal land; unproductive due to salt water; reached only by extreme high tide; constructed into fishpond by deep excavation – Zone B: generally elevated; can still be reached by tides; high dikes are not necessary; deep excavation is required – Zone C: elevation is low, within the ideal range of pond bottom elev.; less excavation; extreme acidity occurs because of the presence of vegetation; ideal zone – Zone D: elev. is low, slightly higher than the lowest low tide; exposed to constant wave action; requires higher dikes & wave protection structures; no acidity problem 5. Vegetation This refers to plant life -- big sturdy trees, woody trees, shrubs and bushes, sedges, weeds, and herbs. Types of vegetation which indicate the physical and chemical properties of soil: – Avicennia (api-api) and pagatpat trees – abound in elevated areas and indicate less acidic and productive soil and highest suitability for fishpond. – Rhizophora (bakawan) trees – mostly found in low areas and indicate high organic content and acid sulfate soil and less suitability for fishpond. – Nypha fructicans (Nipa palm) – abound in sandy soils and indicate low salinity, peaty and acid sulfate soils which have lasting low pH effect on newly constructed pond, and low suitability for fishpond. – Ferns and certain shrubs – abound in low areas. – Grasses – abound in sandy soils. 6. Climatic Condition – Wind and rainfall are the climatic factors affecting site selection and fishpond design. – Data on rainfall and wind direction are guides in planning the design and layout of pond system. – Records of water levels caused by rainfall help in deciding whether to include drainage canal and its dimensions. – Records of rainfall are also useful in computing for the height of perimeter dikes. – Prevailing wind guides fishpond builders in orienting dikes. Partition dikes (secondary dikes) of a pond system should run parallel with the prevailing wind to lessen exposure of their side lengths to wave action, thus protecting them getting eroded. Prevailing Winds in the Philippines 1. Southwest monsoon (Habagat) – prevailing wind that comes from southwest blowing towards northeast direction and occurs during the rainy season (June to October). 2. Northeast monsoon (Amihan) – prevailing wind that originates from northeast blowing towards southwest direction and occurs during the dry season (November to February) 3. Trade wind (Salatan) – the wind that blows from an easterly direction toward the equator and occurs usually from March to May. Four Climatic Zones or Weather Types in the Philippines Type I – Two pronounced seasons: dry from November to April and wet from May to October (Regions 1 and 3, West Region 4, West Mindoro, West Palawan, West Panay Island and West Negros) Type II – No dry season with a very pronounced rainfall from November to January. This covers the regions along the eastern coast which are neither sheltered from the “Amihan” and the “Salatan” nor from cyclone (East Region 4, Bicol Region, Samar, Leyte, North Cebu, Bohol and East Mindanao) Type III – Seasons are not very pronounced; relatively dry from November to April and wet from May to October. This belongs to areas partly sheltered from “Amihan and Salatan” and open to “Habagat” and cyclonic storms (Abra, Mountain Province, Masbate, East Panay Island, East Negros, Misamis Oriental, Cagayan de Oro). Type IV – Rainfall is more or less distributed throughout the year. This belongs to Region 2, East Mindoro, Central and Southern Mindanao, Basilan, Sulu and Tawi-Tawi.  Types I and III, where the dry season lasts for 4-6 months followed by the rainy season, are more favorable than Types II and IV, where the rainfall is distributed throughout the year. In the latter types of weather, it is difficult to grow lab-lab; lumut which gives lower yield becomes the dominant fishfood. Other factors to be considered in the selection of a good fishpond site: a. proximity to market e. availability on construction materials b. proximity to fry source f. availability of fertilizers, supplementary food, etc. c. availability of credit g. availability of ice and cold storage facilities d. availability of skilled local labor h. peace and order condition in the locality B. Factors to Consider in Selecting Sites for Fishpens or Fish Cages 1. Water quality Dissolved oxygen – the site must have a stable DO level of 4 ppm all throughout. Turbidity soil/Transparency of water – the site must be free from prolonged brownish color and deep green and blue-green color. Pollution – the site must be free from pollutants and should not be a passageway of pollutants. Salinity & temperature – these should not fluctuate or vary abruptly by more than or equal to 5 ppt and 5 0 C in the site all throughout. 2. Bottom soil – this should be sandy clay or clay loam soils. Too much silt and decomposing organic matter must be avoided. 3. Natural hazards/calamities – the site must be sheltered against strong winds and high waves. 4. Water or tidal current – this should range from 10-60 cm/sec or 6-36 m/minute. Current speed more than this range is avoided to prevent fishes from spending too much energy swimming. 5. Water depth – should not be more than 8 meters and less than 1 meter (for fishpens and fixed cages) and not less than 3 meters for floating cages. Figure 1. Zonations in coastal areas Appendix A Appendix B  Appendix C VIEW OF SAMPLE AFTER DESCRIPTION OF TEXTURE ROLLING No roll, sand, loamy sand Beginning of a roll, sandy loam The roll is continuous, but breaks when ring is formed, loam and silt loam The roll is continuous, but the ring cracks; clay loam, sandy clay loam, silty clay loam The roll is continuous; the ring is also complete; silty clay; clay and sandy clay Appendix D  UNIT III ENGINEERING AND SITE SURVEY Unit Objective This unit aims to: 1. Name and define the specific uses of the different surveying equipment/instruments and methods; 2. Discuss and demonstrate how to determine one’s pace factor as one direct method of measuring an unknown distance; 3. Present the different formulas and explain how these formulas are computed and used; 4. Discuss and demonstrate how to use and operate the different surveying equipment, instruments, devices and methods; 5. Master how to determine the azimuth, back azimuth, bearing, back bearing of the lines, or the horizontal angles as well as the different directions of the land surface using the engineer’s transit or just the small marine magnetic compass (2-nch diameter); 6. Discuss the different ways of leveling; 7. Show how to make a land surface survey with the use of the engineer’s transit or a small marine magnetic compass and a plastic hose; and develop the skill of plotting a map of a surveyed site; 8. Show how to determine the ground elevations using the engineer’s transit or a simple device, like the plastic hose filled with water as a leveling device, and how to plot the elevations taken in the site survey. A. Engineering Survey Equipment 1. Tape (steel, synthetic) – the most common measuring device (Figure 2). 2. Engineer’s transit – an instrument with magnetic compass, level, and telescope fastened to a tripod. It has accessory devices, like stadia rod and range pole (Figures 3 and 4). * It is used for the following purposes: – measuring horizontal angles (bearings or azimuth of the lines) and vertical angles – measuring vertical and horizontal distances – determining ground elevations – leveling operations – for prolonging lines 3. Magnetic compass – an instrument usually in circular shape graduated from 0° to 360° and provided with magnetic needle that always points the magnetic north. It is also provided with another needle from which the azimuth of a line is read. This is made of metal, fiberglass, or plastic covered on top with transparent glass (Figure 5). – This is used for determining the azimuth or bearing of a line as well as the different directions of the land surface. 4. Level – an instrument used for measuring the vertical distance in leveling operation and for determining the ground elevation in the absence of an engineer’s transit (Figures 6). Figure 2. Different types of tape Figure 3. Engineer’s transit Figure 3. Stadia Rod Figure 5. Compass and tripod Figure 6. Abney Hand Level B. Measurement of Distances Two methods of measuring distances 1. Direct method – a method which involves the use of taping/chaining or pacing. – Pacing is a practical way of measuring a distance but not as accurate as taping/chaining. – Pacing can only be adopted after an individual’s pace factor had been determined. Pace factor (PF) is defined as the ratio of the tape distance (premeasured) and the number of paces made in several trials along such a tape distance. PF m/p = Tape Distance (m) Ave. No. of Paces How to Determine the Percentage Error of the Pace Factor? Formula: A. If pace distance in meters, i.e. counted paces multiplied by Pace Factor, is more than the Tape Distance (also in meters). In this situation, the obtained error is to be subtracted from the pace distance to get the nearest estimate of the actual or tape distance. % error = Pace Distance (i.e. counted paces x pace factor) – Tape Distance X 100 Pace Distance For example: = 55m – 50m X 100 73.33 – counted paces 55m x 0.75 m – pace factor = 9.10% 54.99 or 55m – pace distance = 55 x 9.1/100 = 5 Therefore, 55 – 5 = 50m 50m – tape distance B. If pace distance in meters is less than the Tape Distance (also in meters). In this situation, the obtained error is to be added to the pace distance to get the nearest estimate of the actual or tape distance. % error = Tape Distance – Pace Distance (i.e. counted paces x pace factor) X 100 Tape Distance For example: = 50m – 49m X 100 65.33 – counted paces 50m X 0.75 m – pace factor = 2% 48.99 or 49m – pace distance = 49 x 2/100 = 0.98m Therefore, 49 + 0.98 = 49.98 or 50m 50m – tape distance – An unknown distance can be estimated by multiplying the number of paces or strides counted along such a distance by the PF. e.g. 120 paces x 0.85 m/p = 102 m (estimate). 2. Indirect method – a method which involves the use of the engineer’s transit and the stadia rod. This method is known as the stadia method. – Stadia method which uses the transit and the leveling rod is a quick way of measuring distance. Formula: Distance BC = (Upper rod reading – Lower rod reading) x 100 Ex: Distance BC = (3.25 m – 0.5 m ) x 100 = 275 m ½ of Stadia Interval Upper Stadia Hair Horizontal Cross Hair Lower Stadia Hair Stadia Interval a) Insert-Intersection of stadia hairs and level rod as seen in the telescope Level rod Upper Insert reading Middle from hair reading Lower reading Instrument from hair Distance BC B C b) Figures 7a & b. Illustration of stadia method  C. Measurement of Angles and Directions Methods of expressing angles 1. Bearing – it is an angle measured from either north or south whichever is nearest toward the east or the west. The angle is read clockwise or counterclockwise from north or south whichever is the 0o angle. The angle is preceded by N or S and succeeded by E or W. A bearing can never be greater than 90°. Examples of bearings are: N 45° E, N 45° W, S 30° E, S 30° W (Figure 8). 2. Azimuth – it is the angle measured clockwise from a reference point or direction usually North which starts with zero degree. Examples of azimuth are: 45°, 90°, 180°, and 270° (Figure 9). 3. Deflection – this refers to the angle between a deflected line and the prolongation of the preceding line. It is a right deflection angle if it is measured to the right (clockwise) and left deflection angle if it lies to the left (counterclockwise) of the extension of the preceding line (Figure 10). 4. Interior angle – this refers to the angle inside a closed figure, a polygon, between adjacent lines. The sum of the interior angles in a closed polygon is equal to (N – 2)(180°), where N is the number of sides (See figure 11). Example: IAT = (N – 2)(180°) = (5sides – 2)(180°) = (3)(180°) = 540° N N N 45 W N 45 E 315 55 W E W E 135 S 30 W S 30 E S S Figure 8. Bearing of lines Figure 9. Azimuth of lines B 45 D A 60 C Figure 10. Deflection angles For individual interior angle covering two adjacent lines, it is computed from the field data on directions such as bearings or azimuths (Figure 11). Examples: 1. For interior angle A, the bearing of line AB of N 800 E and bearing of line EA of N 110 E will be needed in the computation, including the cross-directional lines North to South and East to West. Hence, Interior angle A (or AIA) = (900 – 800) + 900 + 110 = 1110 2. For interior angle B, the bearings of lines AB and BC, N 800 E and S 850 E respectively, will be needed in the computation. Therefore, BIA = (900 – 100) + 850 = 1650 or = 1800 – 100 – 50 = 1650 N N B N N 80 E 10 5 S 85 E C A 11 n1 n2 n5 Interior angles n3 N 11 E N n4 N E D Figure 11. Interior angles D. Identification of Directions There are 32 points or directions in the earth’s surface which are determined in a compass. Each point measures 11.25 degrees (11 and 15’). The 32 points of compass, arranged clockwise from north, are as follows: N E S W NxE ExS SxW WxN NNE ESE SSW WNW NE x N ES x E SW x S WN x N NE SE SW NW EN x N SE x S WS x S NW x N ENE SSE WSW NNW ExN SxE WxS NxW These 32 points of compass are categorized into: Principal points – N, S, E, W. Half cardinal points (secondary) – NE, NW, SE, SW. Intermediate points (tertiary) – NNE, ENE, NNW, WNW, SSE, ESE, SSW, WSW. By points – N x E, NE x N, and other directions with x. X – is read as “by.” Example, N x E N by E E. Measurement of Areas Land areas can be determined with the use of the following methods: 1. Use of different formulas of the following geometric figures: a. Square A = S2 where, A = area (in square units); S = length of the sides expressed in linear units b. Rectangle or Parallelogram or A = LW where, L = length; W = width c. Triangle h h h equilateral isosceles right A = ½bh where, b = base of the triangle; h = height of the triangle d. Trapezoid A = (b + c) h where, b = base of the trapezoid; c = crown; h = height 2 e. Circle A = r2 where, = 3.1416; r = radius 2. Triangulation method (indirect method by scaling or mapping) 2.1. Heroe’s formula A = s (s – a) (s – b) (s – c) where a, b, & c are sides of the triangle s = ½ (a + b + c) C b A a c B Sine formula A = ½ (a) (b) (Sine C)  where C = the angle included between sides a & b B How to solve for side c or the hypotenuse? Use the formula c a below: ______ A c or H = √ a2 + b2 b C 3. Trapezoidal rule (or area by offset from straight line) 3.1. A = b (h0/2 + h1 + h2 + h3 + … + hn/2) where b = length of the common interval between the offsets h0, h1, h2, h3, …, hn or: 3.2. A = (h0 + hn + 2Sh) x d 2 where h0, hn = height of end offsets Sh = sum of offsets (except end offset) d = distance between offsets Example: d = 30 m 30 m 30 m 30 m A B hn = 10 m h0 = 35 m h1 = 25 m h2 = 30 m h3 = 40 m C D Solution: For 3.1. A = 30 (35 m/2 + 25 + 30 + 40 + 10 m/2) = 30 (17.5 + 25 + 30 + 40 + 5) = 30 (117.5) = 3525 m2 For 3.2. A = (35 + 10 + 2(95) ) x 30 2 = (35 + 10 +190) x 30 2 = 235 x 30 2 = (117.5) (30) = 3525 m2 F. Measurement of Perimeter and Circumference a. Square Ps = 4S, where 4 is the number of sides; S = length of each side. Ex: (4) (10) = 40 m  b. Rectangle and Parallelogram P = 2L + 2W, where P = perimeter; L = length; W = width Ex: 2 (20) + 2 (10) = 60 m c. Circumference Co = r2 = A Ex: r2 = 9 3.1416 = 2.865 r = r2 r = 2.865 = 1.693 D = 2r or (r)(2) D = 2 (1.693) = 3.386 C0 = D C0 = (3.1416)(3.386) = 10.64 m where, r2 = radius squared ; r = radius ; D = diameter ; Co = circumference of a circle G. Laying Out of Perpendicular and Parallel Lines This is usually encountered in the actual layout of pond dike. Two methods of laying out perpendicular lines 1. The 3-4-5 method. These are actually numbers which form a right triangle, the 3 of which is the shorter side, the 4 is the measurement of side perpendicular to the shorter side and the 5 is the hypotenuse side. For example, it is desired to layout the center line of dike YZ perpendicular to dike WX at Z. Y center line of proposed dike 40 m 50 m W X Z 30 m Figure 12. The 3-4-5 method in laying out perpendicular lines 2. Intersection method This method applies on relatively clear ground where the described arc can be marked or seen. Y Point of intersection 50 m 50 m W X 30 m Z 30 m Figure 13. The intersection method  Laying Out Parallel Lines Perimeter dike WX is to be laid out parallel with YZ at a distance of 120 m. Between WX and YZ erect perpendicular lines ST and UV that is equidistant with each other or that line SU should be of equal length with line TV (Figure 14). 160 m S 15 15 U W X 20 20 120 m Y Z T V Figure 14. Laying out parallel lines H. Topographic Survey Definition of Terms a. Mean sea level It is the average height of the surface of the sea from all stages of the tide over a 19-year period, usually determined from hourly height readings. b. Datum plane It is any level surface to which elevations are referred. In very extensive surveys, the mean sea level is taken as the datum. However, for an average fish-farm survey an arbitrary datum is taken by establishing a benchmark. c. Benchmark (BM). It is an established and permanently located station or point on the ground, the elevation of which is known. Benchmark elevation may be known or assumed. This should be established on permanent object near a construction project. d. Elevation (El) It refers to the vertical distance of a ground point from the reference datum. e. Station (Sta) It is any point where a rod reading is taken and is generally along the line being run. f. Back sight (BS) It is a rod reading taken in a point of known elevation. It is also known as plus sight since it is always added. g. Foresight (FS) It is a rod reading taken in a point of unknown elevation. It is also known as minus sight since it is always subtracted. h. Turning point (TP) It is an intermediate station or reference point whenever the instrument is moved from one setup to another. It is the station that is sighted twice. i. Height of the instrument (HI) It is the relative elevation of the line of sight of the instrument. j. Ground profile It is a graphical representation of the ground surface showing the change in elevation along the horizontal distance. Leveling * Two Methods of Leveling 1. Differential leveling It is the operation that determines the difference in elevation of two points, say A & B, which are a distance apart. Two cases of differential leveling: a. Leveling with two points A & B visible from the instrument (Case 1) (Fig. 15) Level line of sight BS = 1.4 m FS = 0.8 m HI H2 H1 ElB B ElA = 5 m A Figure 15. Case of two points visible from the instrument To determine the elevation of point B with Case 1, the elevation of point A must be known or assumed, say 5 meters. With this elevation at A, the elevation at B could be determined by the following formula: HI = ElA + BS = 5 m + 1.4 m = 6.4 m Then, ElB = HI – FS = 6.4 m – 0.8 m = 5.6 m 2. Leveling with objective points within A (or BM1) and B (or BM2) not visible in a single instrument-sighting set-up (Case 2) (Fig. 16)  BS FS 1.55 m 1.1 m BS FS BS FS 1.35 m 1.4 m 1.42 m 0.9 m BS FS 1.5 m 1.0 m ELB = ? BS FS 1.4 m 0.8 m TP4 TP3 TP2 BM2 TP1 BM1 ELA = 5 m Figure 16. Leveling procedure in the case of invisibility of objective points in single instrument To determine the difference in elevation between BM1 and BM2 (figure16) a series of differential leveling is done. The instrument is moved and set midway of turning points (TP) and the backsight (BS) and foresight (FS) readings are then taken. Results of the computation of elevation in case 2 are presented in Table 1. Table 1. Data on series of differential leveling as determined by Engineer’s transit Sta BS (m) HI (m) FS (m) Elevation (m) BM1 (A) 1.40 6.40 - 5.00 TP1 1.50 7.10 0.8 5.60 TP2 1.42 7.52 1.0 6.10 TP3 1.35 7.97 0.9 6.62 TP4 1.55 8.72 0.8 7.17 BM2 (B) - - 1.1 7.62 In determining the elevations in a series of differential leveling using a transparent plastic hose or tubing, an alternative formula can be adopted as follows: El = (BS + PE) – FH Where, El = Elevstion BH = Back height PE = Preceding elevation FH = Front height  BH FH 1.55 m 1.1 m BH FH BH FH 1.35 m 1.4 m 1.42 m 0.9 m BH FH 1.5 m 1.0 m ELB = ? BH FH 1.4 m 0.8 m S5 S4 S3 BM2 S2 BM1 ELA = 5 m Figure 17. Leveling with the use of plastic hose Results of the compilation of elevations in case 2 using plastic hose are presented in Table 2. Table 2. Data on series of differential leveling as determined by plastic hose Sta BS (m) HI (m) FS (m) Elevation (m) BM1 (A) 1.40 6.40 - 5.00 2 1.50 7.10 0.8 5.60 3 1.42 7.52 1.0 6.10 4 1.35 7.97 0.9 6.62 5 1.55 8.72 0.8 7.17 BM2 (B) - - 1.1 7.62 2. Profile leveling It is the operation that determines the difference in elevation of points along a prescribed line measured at intervals. It is a leveling process in ahich several intermediate sights (foresights) are taken in each instrument set-up. Turning points and back sights are also established in this method of leveling. Usually, the instrument is set-up off the centerline so that sights would be of uniform distances (fig. 18). Computation for the HI is the same as in the differential leveling. Since in one instrument set-up, there are several foresights made, then the elevation of stations shall be computed by subtracting each of such foresights from only one measurement of HI (Table 3).  BM= 15 m BS= 1.0 m FS = 1.5 m 0+00 HI FS = 1.76 m 0+25 FS= 1.5 m FS = 1.8 m TP HI BS= 1.75 m FS = 2 m 0+50 0+75 FS = 2.2 m FS = 2.1 m FS = 2.25 m FS = 2.8 m Centerline of water supply canal 1+00 FS = 2.5 m FS = 3 m 1+25 1+50 1+75 2+00 2+25 Figure 18. Profile leveling procedure Table 3. Data on profile leveling as determined by Engineer’s transit Sta BS (m) HI (m) FS (m) Elevation (m) BM 1.0 16.0 - 15.00 0+00 - -do- 1.50 14.00 0+25 - -do- 1.76 14.24 0+50 - -do- 1.80 14.20 0+75 - -do- 2.00 14.00 1+00 - -do- 2.20 13.80 TP 1.75 16.25 1.50 14.50 1+25 2.10 14.15 1+50 2.25 14.00 1+75 2.50 13.75 2+00 2.80 13.45 2+25 3.00 13.25  Transit Stadia Method of Topographic Survey The following describes the procedure of determining ground elevations using the engineer’s transit level with a horizontal circle and stadia rod. A transit may be substituted for the level if care is exercised in leveling the telescope. It is assumed that a benchmark (BM) with known elevation has been established. Establish your position from a point of known location on the map. In figure 19, point A is “tied” to a point of know location on the map, such as corner monument “B” of the area. This is done by sighting the instrument on A at B and noting down the azimuth and the distance of line AB. The distance of A from B is determined by the stadia rod. D E C A BM B Figure 19 1. Land Surveying Survey of area using a compass or a transit When making a land survey enclosing an area, it is customary to begin at some convenient corner which can be easily identified and described to take bearings and distances in order around the site. The instrument (transit or magnetic compass) is then positioned and the instrument man sights it to a point of known location (benchmark or reference point) such as the corner monument or other fixed land marks such as trees. The instrument man takes down the bearing of line toward the benchmark (BM) to locate his position on the map. From the point of the instrument, the instrument man may opt to sight all of the stations or points covering the object site without moving it from station to station and take their bearings and distances. Or to move the instrument from one station to the other until all stations are sighted for their bearings and distances.  C D E S3 S4 TP TP B F S1 A G S2 S5 TP TP TP Instrument Position (IP) IP BM BM Figure 20 a and b Table 4. Land surveying where the instrument is positioned steadily on one point Station Azimuth Back Bearing Back Distance Total Area Azimuth bearing IP-BM 130° S 60° E IP-A 270° 90° W IP-B 318° N 42° W IP-C 334° N 26° W IP-D 0/360° 0° N IP-E 26° N 26° E IP-F 43° N 43° E IP-G 90° 90° E Table 4. Land surveying where the instrument is moved from station to station Station Azimuth Back Bearing Back Distance Total Area Azimuth bearing S1-BM 135° S 45° E S1-S2 282° N 78° W S2-S3 11° N 11° E S3-S4 90° 90° E S4-S5 192° S 12° W S5-S1 265° S 85° W  UNIT IV POND/PEN/CAGE/RACEWAY LAYOUT DESIGNS, POND WATER STRUCTURES, AND OTHER POND SUPPORT STRUCTURES Unit Objective This unit aims to: 1. Discuss and differentiate the different pond/pen/cage/raceway layouts and designs, classifications of pond water control structures, and kinds of pond support structures. 2. Give and explain the advantage of one type of design over the others. 3. Give the specific functions of the various pond units and pond structures. 4. Impart the technique of determining the percentage area of the different units in a pond system, the size of dikes using various height to slope ratios, and the volume of dikes. 5. Develop the skill of making a drawn to scale layout plan of a fishpond, fishpen or fishcage. A. Pond 1. Brackishwater Pond System (BPS) Various Units or Types of Compartments of BPS and Their Uses a. Fry acclimatization pond unit – also called fry box. – It is the smallest compartment and usually measures about 4 – 8 m2. – It is built with small and low dikes within the nursery pond (NP) for holding fry for 1 – 4 days before releasing to the NP. b. Nursery pond (NP) - Similyahan – The second smallest unit with the size ranging from 1 – 6% of the total production area. – NP size ranges 500 – 10,000 m2 per compartment. – It is used for rearing the fry for at least 30 days before transferring to TP. c. Transition pond (TP) – Bansutan – also called holding or stunting pond – The pond unit constructed adjacent to the NP. – The second largest pond unit comprising about 6 – 9% of the total production area. – TP size ranges 1,000 – 20,000 m2 per compartment. – It is a source of stocks for the grow-out or rearing pond for the whole year round of subsequent crops. d. Rearing pond (RP) – Palakihan – also called grow-out pond or production pond – The largest pond unit in the pond system occupying about 80% of the total production area. – RP size ranges 1 – 10 hectares per compartment. – The pond unit that is for rearing fish fingerling or post fingerling to marketable or large-sized fish. e. Catching pond (CP) – The pond unit constructed adjacent to the gate inside a grow-out pond and maybe inside a transition pond and a nursery pond. – The CP size ranges 1 – 1.5% of every RP compartment and 2% of NP’s and TP’s surface areas. – It serves as a confinement area for the fish during harvest. f. Food growing pond (FGP) – This pond unit is optional and may be built if deemed necessary. – A pond compartment from RP set aside for growing live food organisms, e.g. lablab, at high density to augment the food grown in other RPs. Hence, it is called a kitchen pond. Depending upon the purpose and the availability of area, the BPS could just be an NP alone; an RP with TP; an RP alone; or an RP with NP and TP. Brackishwater Types of Pond Layouts 1. Conventional type (Fig 21) – an old or traditional type of layout with small percentage area of NP and where straight-run culture method is adopted. 2. Radiating type (Fig 22) – is also the same with the conventional type but has shorter supply canal which suggests economy in dike construction than the former type. 3. Modular or Progressive type (Fig 23) – an improved layout type which is provided with 3 RPs called production process stages (PPS) with size ratios that are progressing, e.g. 1:2:4 or 1:3:9 which means 1x:2x:4x in areas to where grow-out culture of fish passes before harvest. A type which allows 6 – 8 crops per year. 4. Multiple stock or harvest type (Fig 24) – a type which has no TP but instead fish holding canal (FHC) for fingerlings to be reared in the RPs for the whole year round. A type where stocking 2 – 4 different size groups at different times and selective harvests of larger at different times are practiced. A straight-run method is also adopted in this type. Figure 21. Conventional pond design Figure 22. Radiating pond design  Figure 23. Modular pond design Figure 24. Multi-stock pond design  Table 5. Comparison of various types of brackishwater pond layouts in terms of production and percentage sizes of pond units. Types of Layout Percentage size of pond unit a/ (Production: kg/year) Nursery Pond Transition Pond Rearing Pond Conventional 1% of total production 9% of TPA 80% of TPA (1000 – 2000) area (TPA) Radiating 1% of TPA 9% of TPA 80% of TPA (1000 – 2000) 80% of TPA This pond unit has Modular/Progressive 4% of TPA 6% of TPA 3 production (1800 – 3000) process stages (PPS). Each stage follows a ratio of 1:2:4 or 1:3:9 Multiple stock/harvest 6% No TP. Instead fish 84% but 9-10% of (1000 – 2000) holding canal for this is allocated for fingerlings is fish holding canal allocated for each (FHC). RP. a/ - For each type of layout, some 10% of the total area is used for canals, catching ponds and dikes. 2. Freshwater Pond System (FPS) Various Units of FPS and Their Uses a. Breeding pond (BP) or hatchery pond (HP) – is the pond unit for mating of spawners or for production of fish larvae. b. Nursery pond (NP) – is the pond unit for rearing the larvae up to fingerling to juvenile stage. c. Transition pond (TP) – is the pond unit for holding fingerlings or that serves as the depository bank or as the source of post fingerlings from grow-out production. d. Rearing pond – is the pond unit for growing-out fish fingerlings to marketable-sized or large- sized fish. Depending on the purpose and the availability of area, freshwater pond system could just be a BP with NP or both units in just one compartment. It could just also be a combination of TP and RP which have separate compartments or just an RP without TP. Freshwater Types of Pond Layouts 1. Barrage pond type – a pond type usually filled by rainfall or by a spring water. A series of ponds in this type require drainage pipes and overflow ditch. 2. Diversion pond type – a pond type which has a diversion canal to serve as a passageway of water from the main water body, e.g. creek, brook and the like. * Two types of layouts of a diversion pond a. rosary type – a type in which series of ponds are built one after another in a string. In this type of layout, all ponds drain into each other -- upper pond drains to the lower pond. b. parallel type – a type in which ponds are built parallel to each other and each pond of which has an inlet and an outlet. * Advantages and disadvantages a. Barrage ponds vs. Diversion ponds – Diversion ponds are less likely to overflow and the water source is often more dependable throughout year than with barrage ponds. – Barrage ponds require less construction and are likely to be cheaper. b. Rosary types vs. Parallel types of diversion ponds – A parallel diversion ponds are better in terms of water management since each pond compartment can be operated or worked out independently without involving the other ponds. – On the other hand, rosary types are cheaper and easier to build. Pond Water Control Structures Dikes and Gates 1. Dikes * Types of dikes a. Primary, main or perimeter dike (Fig 25) – It is the dike that encloses and protects the entire pond system. – It is the tallest and widest among the types of dikes with the most gradual slope. – It is the dike that should be provided with a freeboard of 0.3 - 1 meter after shrinkage and settlement. – The dike that is usually provided with puddle trench measuring 30 cm in width and 50 cm in height dug up along the central path of such a dike. o Freeboard – is the additional height of a structure, e.g. main dike, above high water level to prevent overflow. b. Partition dikes * Two classification of partition dikes b.1. Secondary dikes (Fig 26) – which are smaller than the main dike with gradual slope and which enclose the NPs, TPs and RPs. b.2. Tertiary dikes (Fig 27) – the smallest and lowest in height dikes which enclose the catching ponds and fry acclimation pond. * Parts of dikes The following table (Table 6) presents the parts of the 3 types of dikes and their size specifications: S I Z E (meter) Parts Main Dike Secondary Dike Tertiary Dike Crown or top width 2 – 4 b/ 1–2 15 ha of pond. d) Each opening must have 4 pairs of grooves: 2 pairs for slabs or flashboards to fit at the central gate portion and 2 pairs for screens – one at each end of the gate. e) Its 4 wings should be constructed 450 outward. f) The gate foundation must be rigid and stable. Its floor and apron should rest or sit on a combination of wooden piles (tulus) and layers of boulders and gravel or just wooden piles alone. g) It must be provided with cut-off walls. h) It must be provided with adequate reinforcement steel bars which are spaced 40 cm center to center. Vertical bars of 12–13 mm in and horizontal bars of 10 mm in should be used. b. Secondary gates (36a-b) – Are those gates situated on the partition dikes. – Regulate water level in the NP, TP and RP units. – Are smaller than main gate with 1 – 2 openings per gate with a width of 0.8 – 1 m per opening. – Are made of either concrete hollow blocks, reinforced concrete mix, or wood. c. Tertiary gates – Are those gates installed in the catching ponds. – Are the smallest gates with opening width of 0.5 – 0.8 m * Classification of gates: sluice gate and monk gate a. Sluice gates (Fig 28a-f) – are those pond gates constructed open on top (not concealed) across the dikes with 2 pairs of grooves provided at the central portion of the sidewalls for fitting the slabs and another 2 pairs for each of the gate ends for the screens. – Are easy to mention and allow rapid water discharge rates. – Do not allow passage of vehicular transport across them. b. Monk gates (Fig. 29a-b) – are those gates whose central bodies are concealed in the dikes, i.e. the top of the main body parts of the gate is covered with soils which allows motor vehicles to pass over. * Components/Parts of water control gate (main gate) a. Floor – the floor serves as the foundation of the structure and this must be lower than the pond bottom elevation. The floor of the main gate must not be exposed during extreme low tides. b. Apron – the apron generally rest on the foundation piles which are made of seasoned bamboo driven at 0.3 m intervals into the soft soil with the butt end up. This serves as the protection to scouring and future seepage of water at the gate’s sides. c. Cut-off walls – these are provided at both ends of the gate floor to prevent seepage and undercutting of water over the gate’s foundation. They extend down into the soil at a minimum depth of 0.6 m. d. Side or breast walls – side walls define the sluice way in addition to their being retaining wall for the dike fill. Grooves or double cleats for flashboards and screens are built on these walls. The top of these walls are as high as the top of the dike. e. Wing walls – these provide the transition from the sluice way into the main canal in addition to retaining the earth at both sides of the gate. The best angle of inclination towards the outside is 45. f. Bridge or catwalk – this is a reinforced concrete slab or thick wooden planks that span the side walls. g. Flashboards – slabs or flashboards are generally wooden planks, 2.5 – 5 cm thick and 30 cm wide inserted into grooves or double cleats. They are used to control the amount of water flowing through the gate. h. Screen – these are usually made of wood bamboo strips or of fine polyethylene meshes attached to a wooden rectangular frame that fit into the grooves. These are used as to prevent the exit of the cultured fish and the entry of predators into the ponds. i. Pillars – In wooden gates, these are vertical supports where wooden walls are nailed. j. Braces – In wooden gates, these wooden frames hold or fasten two or more pillars together or in place. They keep the steady opening of the gate. * Other pond support structures a. Water supply canals (WSC) – these canals serve the purpose of supplying and draining water to and from the pond. The main water supply canal starts from the main gate and usually transverse the central portion of the fish farms. The floor of this is sloping towards the gate floor. A 10–15 ha pond is provided with WSC having a width of at least 3 meters. a. Main Water Supply Canal (MWSC) Starts at the main gate usually traverse the central portion of the fish farm Sloping towards the floor of the main gate  Generally, canal bed has the slope of 1/1,500 or one meter vertical difference for a horizontal distance of 1,500m 1m opening MG have a canal bed of at least 3.0m wide, that can supply a 10-15ha with dike slope of 1:1 b. Secondary water supply canal Starts from MC to inner portion Smaller than MC Canal bed of width of 2.0m c. Tertiary canal Supply water to NP & TP Usually considered part of NP or TP system Modified as CP Canal bed width of 1.0 -1.5m Capacity of Supply canal Area Trapezoidal cross-section (2zd + b + b) A = -----------------------------d 2 A = zd2 + bd Rectangular cross-section A = b(d) Velocity and hydraulic radius Velocity 1.486 V = --------------- R2/3S1/2 in fps N R2/3S1/2 V = ---------------- in mps N Where, V, velocity (ft/s, m/s); S, longi. slope of canal bottom (ft/ft, m/m); n, coeff. of roughness; R, hydraulic radius (ft, m) Hydraulic radius R = A/P Where, A, area (ft2, m2); P, wetted perimeter (ft, m); R, hydraulic radius (ft, m)  Wetted Perimeter Trapezoidal cross-section P = b + 2√(zd)2 + d2 = b + 2d√1 + z2 zd2 + bd R = -------------------- b + 2d√1 + z2 Rectangular cross-section P = b +2d bd R = --------------- b + 2d Cross-sectional notations and formulae Table taken from Emmanuel Vera Cruz Lecture b. Drainage canals (DC) – these are support structures usually constructed in the outer ides of the pond parallel or perpendicular to the WSC. These are recommended in intensive culture, especially of shrimps, to effect flow-through system and better water management. c. Diversion canal - Protect the farm from being flooded with run-off water from watershed d. Flumes – Flumes are open channels or elevated canals constructed on top of the dike for purpose of supplying well-oxygenated water into various pond compartments. These can be made of concrete hollow blocks, prefabricated concrete slabs, or marine plywood (Fig. 38a - b). These are recommended in semi-intensive and intensive prawn farming. e. Pumps – Pumps are machines used in pumping water into and out of the ponds. These are very necessary during the dry season when the water level is low and the salinity of brackishwater ponds becomes too high (above the optimum). f. Aerators – these are devices used to supply oxygen or agitate or break up the water surface to effect the fast transfer of oxygen from air to water during which time the oxygen in the pond is at critical level, e.g. 5 tons/ha) & run electric aerators continuously from July to the end of Sept or until water temperatures have dropped to 18-20oC & are falling. The economics of that practice should be carefully evaluated.  Figure 25. Main dike Figure 26. Secondary dike Figure 27. Tertiary dike (After BFAR-UNDP/FAO, 1981) Figure 28a. Concrete gate Figure 28b. Wooden gate Figure 28c. perspective view of a single-opening gate Figure 28d.sample specification of double opening gate Figure 28e. single opening gate (After Lijauco, 1977) Figure 28f. double-opening gate After Lijauco, 1977)  Figure 29a. wooden culvert or monk gate Figure 29b. concrete culvert or pipe (monk gate) Figure 30. Foundation support and piling scheme Figure 31. Different types of canals  Figure 32. gravity aerators Figure 33. surface aerator (fountain) Figure 34. Diffuser Figure 35. Turbine aertor Figure 36. Paddle wheel B. Different Fishpen Designs 1. Square 3. Circular 2. Rectangular 400 m 16 has. 1600 m banatan required 100 m/ha If the shape of an area remains the same, you can enclose 4 times the area with only 2 times the amount of fence or banatan. 200 m 400 m 4 has. 800 m banatan 200 m/ha 100 m 1 ha. 400 m banatan 200 m 400 m/ha 50m 100 m ¼ ha. 50 m 200 m banatan 800 m/ha. Figure 37. Square Design of Fish Pen 200 m 1 ha. – 500 m banatan 25 m 100 m 100 m 200 m ¼ ha. 50 m 1 1 ha. 850 m banatan 25 m 250 m 400 m Figure 38. Rectangular Design of Fish Pen If the area enclosed remains constant, the further the shape departs from circular, the greater the amount of banatan required. A square is the most efficient 4-sided figure.  1 Ha. FISHPEN ½ Ha. FISHPEN ¼ Ha. FISHPEN Figure 39. Design of Circular Fishpen C. Cage Components or Parts and Designs Floating cage components 1. Cage bag 3. Collar and supports 2. Frames 4. Mooring systems * Cage bag – is a part of the cage that holds the fish Two Classifications of materials used for cage bag. 1. Flexible netting materials composed of the following: a. natural fibers, e.g. cotton nets b. synthetic fibers (man-made or artificial), e.g. nylon, polyethylene net (PE) – Nylon and polyethylene nets are the most common kind being used because they are strong and light, cheap, and can be treated with anti-fouling chemicals. 2. Rigid and semi-rigid materials (or in short rigid meshes), e.g. extruded plastics, galvanized steel, and plastic-coated steel. – Cages made of rigid mesh materials are called rigid cages. * Frame/Framework – is used to suspend the net cages or cage bags in the water and to provide sufficient weight to maintain stability of the net cages against tidal waves, currents, or monsoon winds. – Frame could be bamboo, lumber, metal or synthetic material. * Collars and Supports (these are floatation materials), e.g. rectangular styrofoam, foam-filled drums, foam-filled tubing, air-filled drums, full length bamboos. * Mooring systems: a. Anchor lines – are ropes made of nylon, polyethylene or polypropylene. This measures 1.8 – 2 cm in diameter. b. Anchor weights/sinkers are materials used to hold the cage/s in place. These are may be iron anchor, concrete blocks, bags of sand or pebbles, iron rod, or wooden peg. Different Cage Designs 1. square 3. circular 2. rectangle 4. octagonal 3m 9 m2 9 m2 3m 3.4 m Figure 40 Figure 41 9 m2 2m 4.5 m Figure 42  9 m2 Figure 43 – Small-sized circular cages and pens and to the extent of tanks are for fish that swim incessantly around, while small square and rectangular units are for slow-moving fish or those fish which do not move around incessantly. D. Different Raceway Designs water discharge inflow CULTURE UNIT aeration water inflow pretreatment discharge CULTURE UNIT aeration water discharge inflow pretreatment pretreatment CULTURE UNIT Figure 44. Single-pass raceway systems (top to bottom): no treatment, with treatment and aeration, and with pre- and posttreatment.  raceway 1 raceway 1 raceway 1 raceway 1 Figure 45. Parallel raceway units. raceway 1 raceway 1 raceway 1 raceway 1 raceway 1 raceway 1 raceway 1 Figure 46. Raceway units in series: on flat ground (top) and on sloping ground (bottom). Figure 47. Perspective view and parts of a floating cage Figure 48. Cluster module of fish cages Figure 49. Perspective of a fishpen showing nursery pen within the grow-out enclosure.  SCALING Scale is the ratio of the distance on the map or drawing and the distance on the ground. OR, scale is the distance or measurement in the map or drawing relative to the ground. Scale = Map/Drawing Distance (m) Ground Distance (m) Example of scale is 1:1000 m In the scale, the value of 1 represents the ratio of map (in meter) to the 1000 m distance of ground. Problem. To determine the ratio of drawing/map with the following ground measurements of 125 m long and 80 m wide is to do the ratio and proportion formula, thus: 1 m (map)__ = X (map)____ 1000 m (ground) 125 m (ground) 1000 m X = (1 m) (125 m) X = 125 m2 1000 m X = 0.125 m or 12.5 cm or do the division and multiplication process, thus a) = 1 m__ x 125 m 1000 m = 0.001 x 125m = 0.125 m or 12.5 cm or b) = 1 x 125 = 125_ = 0.125 m or 12.5 cm 1000 1000 Map – is a graphical representation of the ground drawn to scale. Marginal Information of the Map 1. Sheet Name or Title – means the name of the map. This should be placed on top of the map. 2. Sheet Number. This should be placed on the upper right-hand corner of the map. 3. Scale. This should be placed center down of the map. 4. Legend. This should be placed on the lower right-hand corner of the map. 5. Edition Note. Should be placed on the lower left-hand corner of the map. Guides in Scaling 1. To determine the measurement of every line in the drawing, every dimension or linear measurement in the ground surface or field should be divided by the given scale. Ex. Given scale is 1:1000 m field measurement are:  70 m 90 m 100 m 85 m 2. If scale is changed to a bigger value, the drawing or figure of the same dimensions of a lot becomes smaller. Ex. 1:1000 m is changed to 1:2000 m Solutions: 70 m_ = 0.035 m or 3.5 cm 2000 m 3. If scale is changed to a smaller value from the original (very first) scale, the drawing or figure of the original dimensions of a lot becomes larger. Ex. 1:1000 m is changed to 1: 100 m Solutions: 70 m_ = 0.7 m or 70 cm 100 m 4. If you want to check the correctness of the work, multiply the line measurement in the drawing (in cm) by the given scale (also in cm) divide by 100 cm/m to determine the linear measurement in the ground surface. Ex. Scale: 1:1000 Solution: 7 cm in the drawing x 1000 scale 7000 cm or 70 m in the ground 70 cm x 1000 = 70 m 100 cm/m  Prime Meridian 35 30 25 20 15 10 5 0 Equator 5 10 15 20 25 30 35 35 30 25 20 15 10 5 0 5 10 15 20 25 30 35 Philippines is between Latitude 10 - 15 N and between Longitude 15 - 20 E Vertical Line is for longitude but its values are horizontalwise. Horizontal Line is for latitude but its values are verticalwise. Longitude – is parallel with prime meridian 1/ Latitude – is parallel with equator 2/ 1/ - prime meridian is the zero (0) – based of longitude 2/ - equator is the zero base of latitude.  UNIT V POND CONSTRUCTION Unit Objectives This unit aims to: 1. Introduce the tools and equipment used in pond construction. 2. Discuss the sequential order of activities to be done in constructing a pond. 3. Develop the ability of preparing a program of work and schedule of activities. 4. Discuss the steps and procedures of constructing a pond system including the pond water control structures and other pond support structures. 5. Show how to calculate the quantities of cement, sand and gravel required in concrete mix in accordance with the specifications of concrete proportion. 6. Develop the ability of preparing a prospectus and a detailed development plan of either brackishwater or freshwater pond. 7. Master how to determine the water discharge capacities of different types of water outlets and inlets. A. Tools and Equipment 1. Tools and light equipment a. bolo, ax, chain saw – for cutting trees. b. carpentry tools – for use in the construction of laborers’ hut, farm house, pond gates, and others. c. digging blades – for excavating blocks of soil. d. shovels – for excavating blocks of soil and for mixing concreting materials manually. e. wheel barrow – for hauling soils and some light supplies and materials. f. bamboo raft or non-motorized banca – for hauling excavated soils into the dumping area. 2. Heavy equipment – for mechanical construction a. dozer crawlers or scrapers – for excavating and leveling of pond surfaces. b. backhoe or hydraulic excavator – for excavating soil. c. pay loader – for loading truck carriers with excavated and/or scraped soils. d. pay hauler or dump truck – for hauling soils from the excavation site to the dumping site. e. concrete mixer – for use in mixing concreting materials. B. Pre-Construction Activities 1. Programming of activities and staffing the project - The purpose of programming is to have a clear flow: a) on how the project will be implemented, b) when to start and end a particular activity, and c) on how the labor force will be managed to work efficiently. 2. Preparation of project cost estimate (Table 7) 3. Preparation of program of work and schedule of activities (Tables 8 & 9). Table 7. Example of estimated project cost. Activities Quantity Unit Cost (P) Total Cost (P) Earthwork a) scraping/clearing 4 ha 12,000.00 48,000.00 b) core trenching 2,115 m 8.00 16,920.00 c) excavation of drainage canal 1,040 m3 40.00 41,600.00 d) construction of dikes and excavation of pond 17,000 m3 45.00 765,000.00 bottom Construction and installation of gates 4 units 30,000.00 120,000.00 Excavation and concreting of water supply canal