Bangus Production

FISHPOND ENGINEERING 1. INTRODUCTION Fish kitty Engineering is the weak of envisionning, marking and constructing ponds including urine lock structures. Although not entirely new in the Fish Farm diligence, it has gained supranational acceptance and plays an outstanding role for the efficiency of the promote wariness as well up as in attaining loftyer farm output. Fishpond Engineering takes into con grimaceration most especi every last(predicate)y the physical structures and economy of construction base on the proper engineering mapping and application. . SITE SELECTION AND EVALUATION OF EXISTING AREAS 2. 1 piss Supply Water supply is the first-class honours degree and most important factor to con boldnessr in the suitableness of a fishpond site. Usually, water supply comes from a river, a creek or from the ocean. It moldiness meet the feeling and quantity requirement of the pond system passim the year. Water quality is affected by the physical, the chemical, and the biologic para thousands.Such para pulsations argon affected by the 1) by-p gatucts and wastes resulting from urbanization, 2) agricultural pollutants such(prenominal) as pesticides and fertilizers, 3) industrial wastes from pulp mills, sugar, anoint refineries, and textile plants, 4) radio-active wastes, 5) oil pollution arising navigational activities, uncontrolled spillage, and oil exploration. some(a) of these parameters be discussed in expatiate under fishpond steering. Poor quality water several(prenominal) durations ca social functions the fouling of gates, screens or metal pipes. This happens when heavy dredging is being conducted in an bea.Heavy dredging sum ups turbidity and causes the release of organic substances embedded in the terra firma. Once these organic substances atomic number 18 released, they use up atomic number 8 causing naughty biological oxygen demand (BOD). Higher BOD causes oxygen depletion which in turn makes the water foul. Similar con ditions also occur during scarf outs. Water supply in soar upwards-fed farms must(prenominal) be adequate especially during some months of the year when the altitude of high water is at minimum. This enigma git be solved by proper gate digit and by the use of pumps.The graze of chroma f execrable of nearby tidal stream needs also to be considered mea sure as shootingment is do during the run dry stream f pocket-sized and during floods. The selective information obtained give the developer the minimum and utmost rates of discharge. These argon important requirements in fish farm design. For details, refer to Annex I. 2. 2 tidal Characteristic and Ground tip The suitability of a soar upwards-fed bea for a bangus fishpond visualise seems on the relationship in the midst of the tidal regular of the subject argona and its ground meridian.The only free source of energy that could be tapped for flooding a brackishwater coastal pond is tidal energy which is available o nce or twice a daytime depending on geographical location. Five reference displace in the Philippines exhibit five peculiarly different patterns during some months of the year. strain 1 shows in a graphical form the relationship of natural ground prime to tidal characteristic. Tables 1 and 2 show such relationships as they are applicable to the six stations of reference. pic common fig 1 Suitability of Proposed Fishpond Site Based on Tidal Characteristic and Ground whirligig. neighborhood Elevations in Meters Above Mean Lower Low H20 Mean High Water (MHW) Mean sea Level (MSL) Mean Low Water (MLW) Pier 13, South Harbor, Manila 0. 872 0. 479 0. 104 Pier 2, Cebu City 1. 50 0. 722 0. 183 Legaspi Port, Legaspi City 1. 329 0. 744 0. 165 Sta. Ana Port Davao City 1. 405 0. 753 0. 101 Port of Poro, San Fernando, La Union - 0. 372 - Jolo Wharf Jolo, Sulu 0. 631 0. 38 0. 034 Table 1. List of Primary Tide Stations and Datum Planes Highest Lowest Absolute Normal occasional e dition R E M A R K S recorded tide recorded tideannual range low/high(range) (m) (m) (m) (m) PHILIPPINES 1. 4 (-)0. 21 1. 25 (-)0. 03/0. 61(0. 64) Tidal variation too San Fernando, La narrow for proper Union fishpond counselling Manila City 1. 46 (-)0. 34 1. 8 0. 14/1. 05(0. 1) Tidal fluctuation s get outly narrow for proper fishpond management Legaspi City 1. 83 (-)0. 4 2. 23 1. 09/1. 40(1. 9) Tidal fluctuation favorable for proper fishpond management Cebu City 1. 98 (-)0. 4 2. 38 (-)0. 03/1. 49(1. 52) -do- Davao City 1. 98 (-)0. 49 2. 47 (-)0. 03/1. 77(1. 80) -do- Jolo, Sulu 1. 19 (-)0. 12 1. 31 (-)0. 03/0. 98(1. 1) Tidal fluctuation slightly narrow for proper fishpond management Table 2. Suitability of Six Tidal Stations of credit for Fish Farms Areas reached only by the high spring tides should be ruled out as it is expensive to move sizable quantities of imperfection during the process of minelaying. There is that other problem of where to place the excess materials. season these kindle buoy be solved by constructing high and wide perimeter encloses, putting up much than dykes lead create narrow compartments resulting in slight stadium intended for fish production. Low areas on the other hand leave behind require high and more formidable dikes which may opine that primer coat entrust gain to be moved long lengths. The pond hind end should not be so low that drain go forthing be a problem. The best cosmetic surgery for a pond bottom therefore, would at least be 0. 2 meter from the datum plane or at an elevation where you fundament maintain at least 0. meter depth of water inside a pond during ordinary tides. This index should satisfy the requirements of both fish and natural fish food. 2. 2. 1 Tides The attractive forces of both the moon and the sun on the earth surface which changes according to the position of the both planets bring virtually the occur rence of tides. Tides recur with great regularity and uniformity, although tidal characteristic vary in different areas all all over the world. The principal variations are in the oftenness of fluctuation and in the date and point of high and low amniotic fluid.When the sun, the moon and the earth are in a straight rakehell, greater tidal amplitudes are produced. These are called spring tides. Tides of abject amplitudes are produced when the sun and the moon form the extremes of a right trilateral with the earth at the apex. These are called neap tides. When high and low waters occur twice a day it is called a semi-diurnal tide. When the high and the low occur once a day it is called a diurnal tide. The moon passes through a apt(p) meridian at a mean interval of 24 hours and 50 proceeding. We call this interval nonpareil lunar day.Observations reveal that the mean interval between two successive high (or low) waters is 12 hours and 25 minutes. Thus, if there is a high wa ter at 1100 A. M. today, the next high water will take place 12 hours and 25 minutes later, i. e. , 1125 P. M. and the next will be at 1150 A. M. of the pursuit day. individually day the time of tide changes an average of 50 minutes. The difference in the sea water take between successive high and low waters is called the range. Generally, the range becomes maximum during the new and full moon and minimum during the first and last quarter of the moon.The difference in the height between the mean higher high and the mean abase low waters is called the diurnal range. The difference in the tide intervals find in the morning and afternoon is called diurnal inequality. At Jolo, for instance, the inequality is mainly in the high waters while at Cebu and Manila it is in the low waters as well as in the high waters. The average height of all the lower of low waters is the mean lower low (MLLW), or (0. 00) elevations. This is the datum plane of reference for land elevation of fish farms .Prediction of tides for several places throughout the Philippines can be obtained from Tide and Current Tables published annually by the Bureau of Coast and geodesic thought (BCGS). These tables give the time and height of high and low water. The actual tidal fluctuation on the farm however, deviates to some extent from that obtained from the table. The deviation is corrected by observing the time and height of tidal fluctuation at the river adjacent to the farm, and from this, the ratio of the tidal range can be computed. From the corrected data obtained, bench marks scattered in strategic places can be established.These bench marks will serve later on as starting order in find elevations of a busy area. 2. 2. 2 Tide prediction There are six tide stations in the Philippines, that is to say San Fernando, Manila, Legaspi, Cebu, Jolo and Davao stations. Reference stations for other places are listed under the Tidal Differences and Constants of the Tide and Current Tables. The pr edicted time and height of high and low waters each day for the six tide stations can be necessitate right away from the table. Tide predictions for other places are obtained by applying tidal differences and ratios to the daily predictions.Tidal differences and ratios are also instal in the Tide and Current Tables. Let us take for example, the tidal predictions for Iloilo on 23 Sept. 1979. Looking through the tidal differences and constants of the Tide Tables, you will find that reference station for Iloilo is Cebu. The predicted time and height of tides for Cebu obtained from the tide tables on 23 Sept. 1979 are as follows High Low duration top of the inning m Height 0004 1. 3 m 0606 0. 14 m 1216 1. 52 m 1822 0. 18 m (The heights are in meters and reck unmatchabled from mean lower low water (MLLW) 0000 is midnight and 1200 is noon). Again, from the table on Tidal Differences and Constants, the corrections on the time and height of high and low waters for Iloilo are as follows Time Height of High Water Height of Low Water + 0 hr. 05 min. + 0. 09 + 0. 3 Thus, the corrected time and heights of high and low waters for Iloilo are High Low Time Height Time Height 0009 1. 52 m 0611 0. 17 m 1221 1. 61 m 1827 0. 21 m 2. 2. 3 Height of tide at whatever given timeThe height of the tide at any given time of the day may be decided graphically by plotting the tide veer. This can be through with(p) if one needs to roll in the hay the height of the tide at a sealed time. The procedure is as follows On a cross-section paper, plot the high (H) and the low (L) water specifys between which the given time cables lengths (see Fig. 2). Join H and L by a straight breeze and severalize it into four equal parts. Name the points as Q1, M and Q2 with M as the center point. Locate point P1 vertically above Q1 and P2 vertically below Q2 at a distance equal to one tenth part of the range of the tide.Draw a sine curve through points H, P1, M, P2 and L. This curve closely approximates the actual tide curve, and heights for any time may be readily scaled from it. conformation 2 shows the curve on 23 Sept. 1979 for Iloilo. H is 1. 61 m at 1221 hr and L is 0. 21 m at 1827 hr. Since the range is 1. 40 m, P1 is dictated 0. 14 wholes above Q1 and P2 is located 0. 14 units below Q2. The height of the tide at 1430 hr is given by point T to be 1. 22 m. pic Figure 2. Height of Tide at any Given Time for Iloilo on 23 Sept. 1979. 2. 3 colly PropertiesMost of our fishponds are constructed on tidal lands consisting of alluvial demesnes which are adjacent to rivers or creeks near the coastal shores and estuaries at or near sea level elevation. If you pick up a handful of shit and examine it closely, you will find that it is make up of mineral and organic particles of varying sizes. The mineral particles are the clay, back up, and sand while the organic particles are plant and animal matter at various stages of decomposition. Soils are assigned with textural classes depending on their relative property of sand, silt and clay.Each textural class exhibits varying colors which are found on their chemical composition, beat of organic matter and the degree of decomposition. U. S. Department of Agriculture Classification System has categorize soil as GENERAL TERMS Common Names Texture Basic Soil Textural Class Names 1. arenaceous Soils Coarse flaxen Sandy Loam 2. Loamy Soils Moderately Coarse Sandy Loam Fine sandy Loam modal(a) Very fine Sandy Loam Moderately fine Loam disengage Loam Silt 3. bodyey Soils Fine Sandy cadaver form Loam Silty Clay Sandy Clay Loam Clay Silty Clay Loam some properties of soil, which are related to its texture, determine how well suited it is for fishpond purposes.A sandy loam, for instance, is more porous than silty loam and the latter will hold more nutrients than the former. Clay or sandy clay may be the best for dike construction except not as sizeable as clay loam or silty clay loam in terms of growing natural food. So, in general, finer textured soils are superior for fishpond purposes because of their equitable water retention properties. Each soil texture exhibits different workability as soil construction material. Studies conducted show that clayey soil is preferred for diking purposes. Suitability of a soil class as dike material decreases with decreasing percentage of clay present in the multifariousness (see Table 3). classify RELATIVE CHARACTERISTIC COMPACTION CHARACTERISTIC SUITABILITY FOR DIKE MATERIAL PERMEABILITY COMPRESSIBILITY Clay impervious medium fair to correct excellent Sandy clay impervious low good good Loamy semi-pervious high fair to very fair to impervious high poor Silty semi-pervious to medium to good to very poor impervious high poor Sandy pervious negligible good poor Peaty - - - very poor Table 3. Relationship of Soil Classes and Suitability for dike m aterial Sediments are a dominant and observable characteristic in lower areas of brackishwater swamplands.Field observations and laboratory analysis of soil samples interpreted reveal that the majority have a thick layer of loose organic sediments which make them unsuitable for fishpond ontogeny and other infrastructures. Engineering and other technical considerations establish that areas having this graphic symbol of soil are rather difficult to develop because it is directly related to future land development problems such as (1) subsidence and related flood hazards, (2) unavailability of stable and indigenous soil materials for diking, and (3) unavailability of land with adequate load bearing expertness for future infrastructures such as buildings for storage and production facilities.Areas dominated by organic and undecomposed sediments are expected to experience considerable subsidence which ultimately result to loss in effective elevation of the land after development a s a result of drain or controlled water table. Since elevation of most tidal lands converted to brackishwater fishponds are loosely one meter above MLLW, any future loss of elevation out-of-pocket to subsidence shall inc specify the area to severe drain and flooding problems due to blocking effect of seawater during high tides. innate and undecomposed sediments are not a good foundation for dikes nor for diking material. Fishpond areas dominated by this type of soil will mean that there is an inadequacy of indigenous soil materials for diking or filling of lower areas.In the absence of good soil materials, the site under consideration will require importing of soils from the contiguous areas which will make the system of development a very expensive process, or considerable excavation for diking will cause (1) unnecessary exposure of acid organic layers, (2) difficulty in leveling, (3) high bell of dike maintenance and (4) technical problems on seepage losses which will cause difficulty in maintaining water levels in the pond. 2. 3. 1 Field manner for identification of soil texture Sand Soil has granular appearance. It is free-flowing when in a dry state. A handful of air-dry soil when pressed will fall unconnected when released. It will form a chunk which will crumble when lightly touched. It cannot be medaled between thumb and finger when moist. Sandy Loam Essentially a granular soil with sufficient silt and clay to make it somewhat coherent. Sand characteristic predominate. It forms a ball which readily falls apart when lightly touched when air-dry.It forms a ball which bears careful handling without breaking. It cannot be ribboned. Loam A uniform mixture of sand, silt, and clay. Grading of sand fraction is quite uniform from coarse to fine. It is soft and has somewhat gritty feel, notwithstanding is fairly smooth and slightly plastic. When squeezed in hand and pressure is released, it will form a ball which can be handled freely without brea king. It cannot be ribboned between thumb and finger when moist. Silty Loam It contains a cut back amount of finer grades of sand and only a small amount of clay over half of the particles are silt. When dry, it may appear quite cloddy it can be readily broken and pulveriseed to a powder.When air-dry, it forms a ball which can be freely handled. When wet, soil runs together and puddles. It will not ribbon but has a broken appearance it feels smooth and may be slightly plastic. Silt It contains over 80% of silt particles with very little fine sand and clay. When dry, it may be cloddy it is readily pulverized to powder with a soft flour-like feel. When air-dry, it forms a ball which can be handled without breaking. When moist, it forms a cast which can freely be handled. When wet, it readily puddles. It has a tendency to ribbon with a broken appearance it feels smooth. Clay Loam Fine texture soils break into lumps when dry. It contains more clay than silt loam.It resembles clay in a dry condition. Identification is do on physical behaviour of moist soil. When air-dry, it forms a ball which can be freely handled without breaking. It can be worked into a dense mass. It forms a thin ribbon which readily breaks. Clay Fine texture soils break into very hard lumps when dry. It is difficult to pulverize into a soft flour-like powder when dry. Identification is based on cohesive properties of the moist soil. When air-dry, it forms long thin flexible ribbons. It can be worked into a dense compact mass. It has considerable plasticity, and can be moulded. Organic Soil Identification is based on its high organic content.Much consists of thoroughly decomposed organic materials with considerable amount of mineral soil finely separate with some fibrous remains. When considerable fibrous material is present, it may be classified as peat. Soil color ranges from br aver to black. It has high shrinkage upon drying. 2. 4 Studies of Watershed and deluge risk of infectio n 2. 4. 1 Watershed A washbowl is a ridge of high land draining into a river, river system or body of water. It is the region facing or sloping towards the lower lands and is the source of run-off water. The high-risk the area of the watershed, the greater the good deal of run-off water that will drain to the rivers, creeks, swamps, lakes or ocean. Precipitation from a watershed does not unionly drain down as run-off water.A portion of the broad(a)ity rainfall piteous down the watersheds surface is utilize by the plant and becomes a part of the deep ground water supply or seeps slowly to a stream and to the sea. The factor affecting the run-off may be divided into factors associated with the watershed. Precipitation factors take on rainfall duration, intensity and distribution of rainfall in the area. Watershed factors affecting run-off include size and shape of watershed, retention of the watershed, topography and geology of the watershed. The volume of run-off from a wa tershed may be expressed as the average depth of water that would cover the entire watershed. The depth is usually expressed in centimeters. maven day or 24-hours rainfall depth is used for estimating peak discharge rate, thus mickle of Flood Run-off (Q) pic+ S1 Engineering Field Manual For Conservation Practices, 1969, pp 25 to 26 where Q = accumulated volume of run-off in centimeters depth over the drainage area P = accumulated rainfall in cm depth over the drainage area Ia = initial obstruction including surface storage, interception by vegetation and infiltration prior to run-off in cm depth over the drainage area s = potential maximum retention of water by the soil equivalent in cm depth over the drainage area 2. 4. 2 Flood hazardFloods are common in the Philippines due to overflowing of rivers triggered by typhoons and the southwest monsoon rain prevailing over the islands during the rainy season. Overflow of the rivers is largely attributable to the bad pas sage demeanor characteristic such as steep slopes as well as meandering at the lower reach of the river. The network of the tidal streams in some delta areas has been rendered ineffective in conveying the flood-water to the sea due to fishpond construction. Flooding is common in this country and is considered the most destructive enemy of the fishpond industry. The floods of 1972 and 1974 greatly affected the fishpond industry in Central Luzon causing damage amounting to millions of pesos.Because of the floods, fishponds became idle during the time necessary for operators to make repairs and improvements. Floods cannot be controlled, but what is important is to know how a fishpond can be free to some extent from flood hazard. In order to prevent frequent flooding, it is necessary to know the weather conditions in the area where the fishpond suggest is located. The highest flood occuring in an area can be determined by proper gathering of information. In big rivers, the Ministry of Public Works (MPW) records the height of flood waters during rainy seasons. However, in areas where the MPW has no record, the best way is by gathering information from the people who have stayed in the area for many years.The size of the creek, river and drainage line should also be determined to find out whether it can accommodate the run-off water or flood water that drains in the area once the fishpond project is developed. Records of the highest flood in the site, especially during high tide, is very important. It will be the basis in providing allowance for the drainage of flood water coming from the watershed. 2. 5 Climatic Conditions Climate has been described in terms of distribution of rainfall recorded in a neighbourhood during the different months of the year. In the Philippines, it is classified into four climatic zones preferably called weather types, viz. cause I - Two pronounced seasons dry from November to April and wet uring the rest of the year. Type II - No dry season with very pronounced maximum rainfall from November to January. Type III - Season not very pronounced relatively dry from November to April and wet during the rest of the year. Type IV - Rainfall more or less evenly distributed throughout the year. The elements that make up the climate of a region are the same as those that make up the weather, the distinction being one mainly of time. But the elements that reverence most fishpond operators are the rainfall, temperature and the prevailing wind direction because they greatly affect fish production directly or indirectly.Data on rainfall and wind direction are very necessary in planning the layout and design of pond system. Knowing past rainfall records, you can more or less decide whether it will be necessary to include a drainage channel in the layout, and how large it will be when constructed. Knowing past rainfall records will also be necessary in computing the height of the secondary and 3rd dikes. Wind on the other hand, plays a role in fishpond design. Strong wind generates waver actions that destroy sides of the dike. This causes great expense in the construction and maintenance. However, this problem can be minimized with proper planning and design.For instance, longer pond dimension should be positioned somewhat jibe to the direction of the prevailing wind (see Fig. 3). This will lessen the side length of the dike exposed to wave action. This orientation of pond compartments will also have some advantageous effects in the management aspect. pic Figure 3. Layout of Pond Compartments Oriented to the Prevailing Wind Direction Nearly every location is theater of operations to what is called the prevailing wind, or the wind blowing in one direction for a major portion of the year. Monsoons are prevailing winds which are seasonal, blowing from one direction over part of the year and from the opposite direction over the remaining part of the year.Trade winds, which generally come from t he east, prevail during the rest of the year when the monsoons are weak. pic Figure 4. Wind Directions Wave action in ponds is caused by wind blowing across the surface. One cannot get alongly control wave action in ponds although it can be minimized. In typhoon belt areas or in areas where a strong wind blows predominantly, it is better to include wind breakers in planning the layout of ponds. 2. 6 Type and Density of Vegetation Mangrove swamps occur in abundance on tidal zones on the coasts of the Philippines which are being converted into fishponds for fish production, but not all mangrove swamps are suitable for fishpond purposes.Some are elevated and are not economically feasible for development others have too low an elevation to develop. The distribution of mangrove species in tropical estuaries depend primarily on the land elevation, soil types, water salinity and current. It has been observed that api-api and pagat-pat trees (Avicennia) abound in elevated areas while baka wan trees (Rhizophora) are mostly found in low areas. It has also been observed that nipa and high tannin trees have a long low pH effect on newly constructed ponds. Presence of certain shrubs and ferns indicate the elevation and frequency of tide water overrunning the area. Certain aquatic plants such as water lily, eel grass and chara sp. indicate low water salinities.The type and density of vegetation, the size, wood density and root system of individual trees greatly affect the method of clearing, procedure of farm development and construction price. Thickly vegetated areas, for instance, will take a long time to clear of stumps. Density of vegetation is classified according to kind, size and quantity per unit area. This is done to determine the toll of land clearing and uprooting of stumps. One method used is by haphazard sampling. The process requires at least five or more samples taken at random, regardless of size, and vegetation is classified according to kind, size and number. Then the findings are tabulated and the average of the samples is determined. However, vegetation of less than 3 cm in diameter is not included.The fall vegetation of the area is determined as follows pic Station genus Nypa BAKAWAN API-API LIPATA BIRIBID (20? 20) NoAvNo. . e. Si ze b = origin GD h = height or distance The total area of the irregular figure is equal to the sum of A1, A2, A3, A4 and A5. pattern Find the area of an irregular figure shown in Figure 13 using the triangulation method. Solution pic pic b. Trapezoidal Rule pic Figure 14. Area Determination Using the Trapezoidal Rule If a field is bounded on one side by a straight line and on the other by a curving boundary, the area may be computed by the use of the trapezoidal rule. Along a straight line AB, Fig. 14, perpendicular offsets are drawn and measured at regular intervals. The area is thusly computed using the following convention pic Where ho, hn = length of end offsets Sh = sum of offsets (except end offsets) d = distance between offsets Example In Fig. 4, if the offsets from a straight line AB to the curved boundary DC are 35, 25, 30, 40, and 10, and are at equal distance of 30, what is the included area between the curved boundary and the straight line? Solution Area ABCD = pic = = 117. 5 ? 30 = 3,525 sq. m. 3. 2. 3 laying out right angles and parallel lines a. Laying out right angles. For instance it is required to lay out the center line of dike B (see Fig. 15) perpendicular to that of dike A using a tape.A simple corollary on the right triplicity states that a triangle whose sides are in proportion of 3, 4, and 5 is a right triangle, the longest side being the hypotenuse. In the figure, point C is the hybridizeion of the two dike centerlines. One man holds the postal code end of the tape at C and 30 m is measured towards B. Again from C, measure 40 m distance towards A and then from A measure a distance of 50 meters towards B. Line CB should intersect line A B. Therefore, line CB is formed perpendicular to line CA. It is al slipway desirable to check the distances to be sure that no mistake has been make. pic Figure 15. Laying Out Right Angles b. Laying out parallel lines. In Figure 16, CD is to be run parallel to AB.From line AB erect perpendicular lines EF and GH in the same manner described in the previous discussion. Measure equal distances of EF and GH from line AB and the line formed through points C and D is the required parallel. pic Figure 16. Laying Out Parallel Lines 3. 3 Topographic suss out 3. 3. 1 Explanation of common terms a. Bench Mark (BM). A bench mark is a point of know elevation of a permanent nature. A bench mark may be established on woody stakes set near a construction project or by nails driven on trees or stumps of trees. Nails set on trees should be near the ground line where they will remain on the stump if the tree will be cut and removed. Procedure on setting up a bench mark is attached as Annex 4.It is a good idea to mark the nail with paint and ring the tree above and below also in case a chain saw is used to cut down the tree. The Philippines Bureau of Coast and geodesical Survey has established bench marks in nearly all cities and at scattered points. They are generally bronze caps securely set on stones or in cover with elevations referenced to mean sea level (MSL). The purpose of these bench marks is to provide control points for topographic mapping. b. Turning picture (TP). A turning point is a point where the elevation is determined for the purpose of traverse, but which is no longer needed after necessary readings have been taken.A turning point should be located on a firm object whose elevation will not change during the process of base the putz set up. A small stone, fence post, temporary stake driven into the ground is good enough for this purpose. c. Backsight (BS). Backsight is a rod reading taken on a point of known elevation. It is the first reading taken on a bench mark or turning point in a flash after the initial or new set-up. d. Foresight (FS). Foresight is a rod reading taken on any point on which an elevation is to be determined. Only one backsight is taken during each set-up all other rod readings are foresights. e. Height of Instrument (HI). Height of instrument is the elevation of the line of sight above the reference datum plane (MLLW).It is determined by adding the backsight rod reading to the known elevation of the point on which the backsight was taken. 3. 3. 2 Transit-stadia method of topographic survey The following describes the procedure of determine ground elevations using the engineers 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 false that a bench mark with known elevation has been established. a. Establish your position from a point of known location on the map. In Figure 17, point B is tied to a point of known location on the map, such as deferral monument C of the area. This is done by sighting the instrument atC and noting down the azimuth and distance of line BC. The distance of B from C is determined by the stadia-method discussed under area survey. pic Figure 17. Establishing Position from a Point of Known Location on the Map b. Take a rod reading on the nearest bench mark (BM), as shown in Figure 18, previously installed for such purpose. This reading is called the backsight (BS), the rod being on a point of known elevation. The height of the instrument (HI) is then found by adding the elevation of the bench mark (Elev. ) and backsight (BS), thus H. I. = Elev. + B. S. pic Figure 18. Transit-stadia Method of Topographic Survey c.The telescope is sighted to point D, or any other points desired, and take the rod reading. The reading is called the foresight (F. S. ), the rod being on a point of known elevation. Ground elevation of point D is then determined by subt racting the foresight (F. S. ), from the height of the instrument (H. I. ), thus Elevation = H. I. F. S. d. Similar procedure is used in determining the ground elevation of several points which are within sight from the instrument at point B. The azimuth and distance of all the points sighted from point B are read and recorded in the sample field notes such as shown in Figure 19. Sta. Sta. B. S. Occ. Obs. HAT = Highest astronomic Tide GS = Elevation of the ground Surface MF = maximum Flood level FB = Allowance for clean-handed Board %S = Percent shrinkage and settlement 1. The design height of a secondary dike is calculated using the following formula pic Where Hs = Height of the secondary dike HST = Highest Spring Tide GS = Elevation of the ground Surface MR = Maximum Rainfall within 24 hours FB = Allowance for Free add-in %S = Percent Shrinkage and settlement 2. The design height of a tertiary dike is calculated using the following formula pic Where Ht = He ight of the tertiary dike DWL = Desired Water Level GS = Elevation of the ground Surface MR = Maximum Rainfall within 24 hours FB = Allowance for Freeboard %S = Percent Shrinkage and settlement pic Figure 28. number of Different Dikes 4. 3. 3 Canals. About one to two percent of the total farm area is used in the canal system. The main water supply canal starts from the main gate and usually traverses the substitution portion of the fishfarm. The canal bed should not be lower than, but rather sloping towards, the blow out of the water elevation of the main gate. Generally, the canal bed is given a slope of 1/1500 or one meter difference in elevation for a horizontal distance of 1,500 m. A one meter opening main gate will have a canal bed at least 3. m. wide. This width is enough to supply a 1015 hectares fishpond system considering that the canal dikes have a ratio of 11 slope. Secondary water supply canals are constructed in portions of the farm which cannot be reached b y the main canal. It starts from the main canal and traverses the inner portion of the fishpond. It is usually constructed in large fishpond areas and smaller than the main canal. Generally, secondary supply canal has a bed width of 2. 0 m. A tertiary canal is usually constructed to supply water in the nursery and transition ponds. Because of the small size, it is sometimes say to be a part of the nursery pond system.Some fish culturists modify the tertiary canal as a catching pond. This usually happens when the designed tertiary canal is short, Generally, a tertiary canal has a bed width of 1. 01. 5 m. A recreation canal, when necessary, is also constructed to protect the farm from being flooded with run-off water coming from the watershed. It must be strategically located so that run-off will empty on an established disposal area, natural outlets or prepared individual outlets. It should have the capacity to carry at least the peak run-off from the contributing watershed for a 1 0-year frequency storm. The slope of the diversion canal should be in such a way that water flows towards the drainage area.A drainage canal is constructed when there is a need to have a separate canal for draining raising ponds. This is to improve water management in the pond system. It is usually located at the other side of the pond, parallel to the supply canal. A drainage canal is recommended in intensive culture, especially of shrimps. pic Figure 29. human body of Different Canals 5. PROJECT COST AND PROGRAMMING The worst error a prospective fishfarm operator can make is to develop an area without project exist estimates and a programme of development. Development money is wasted, and management of the area may be difficult or impossible. Poor planning is the major cause of project failure and even leads to personal bankruptcy.It is very necessary that homework of the project damage estimates as well as programme of development be done beforehand any construction is starte d. It is important to know approximately how much will be spent to finish the whole project. It is better that one knows how and when the project will be constructed and completed. The importance of the project cost estimates and programme of development should not be underestimated. 5. 1 Project speak to EStimates The cost of development can be estimated based on the 1) data collect in the area, 2) proposed layout plan, and 3) design and specification of the physical structures and other facilities. 5. 1. 1 Pre-development estimates a. For the preparation of Feasibility Study.Whether the fishpond operator will apply for a loan in the Bank or he will use his own money to finance the development of a fishpond project, a feasibility pack of the area is needed. The feasibility study will be his guide in the development and management of the project. All activities such as the development, management and economic aspects are embodied in the feasibility study. It is a specialized work by engineers, aquaculturist and an economist having special knowledge in fishfarming industry. Usually, for the preparation of the feasibility study, the group charges about 2% to 10% of the total estimated cost of development. b. For the Survey of the Area. An area survey includes a topographic survey, and re-location survey.Whether the area is owned by a private individual or by the government, an area survey by a licensed geodetic Engineer is very important for the proper location and boundary of the land. It is one of the requirements in the application for a 25-year Fishpond Lease Agreement in the BFAR and also in the application for a loan in the Bank. It must be duly approved by the Bureau of Lands. A topographic survey is necessary in the planning and development of the project. A re-location survey must be conducted to check the validity of the approved plan as well as to avoid conflict in the future. An area and topographic survey done by a Geodetic Engineer will cost a bout pic400. 00 for the first hectare or a fraction thereof and pic50. 00 per hectare for the succeeding hectarages.Re-location survey is cheaper than the area and topographic survey. c. For the Construction of a Temporary Shelter. see fishpond laborers generally do not live in the locality. To be more effective they need to have a place to stay during the construction activities. For the construction of a shelter house made of light material, assume a cost of pic300. 00/sq. m. of shelter. This includes materials and labor costs. d. For the Construction of Transport Facilities. Flatboats will be needed in the transport of mudblocks. A banca may be used in going to the site. court of construction varies from locality to locality. A blandboat with dimensions of 8 ? 4 ? 14 will cost around pic500. 00.A small banca will cost around pic600. 00. e. For Representation and Transportation Expenses. This item is not included in the cost of development of a fishpond project. However, it app ears that a big amount is being incurred in representation and theodolite expenses before the project is started. Example of pretermititures are follow-ups of survey plan of the area, FLA application and bank loan. Other expenses are incurred in canvassing of supplies and materials, survey of manpower requirement and equipment needed in the development of a project. Representation and transportation expenses cover about 1020 percent of pre-development cost. 5. 1. 2 Development Proper. a.For the glade of the Whole Area. Clearing the area of vegetation can be divided into three categories, namely 1) cutting and chopping, 2) Falling and burning, and 3) uprooting and removal of stumps and logs. Generally, cutting and chopping costs about pic500. 00 per hectare piling and burning costs about pic300. 00 per hectare and for the uprooting of stumps and removal of logs, costs depend on their size and number per unit area. A hectare pond, for instance, having 200 stumps of size below 15 c m. in diameter will cost about pic800. 00. Stumps numbering 50 pieces with diameter over than 15 cm. will cost about pic1,000. 00 per hectare.Cost for the clearing depends upon the prevailing price in the locality. b. For the Construction and Installation of Gates. Cost of construction and installation of a gate can be calculated based on its design and specification proposed in the area. The two kinds of gate commonly constructed in fishponds ( concrete and wood) will be discussed separately. 1. Estimating the cost of construction and installation of a concrete gate a. Based on the plan of a concrete gate, determine the area and volume of the walls, wings, ball over, bridges, toes, aprons and cut walls and compute for the total volume using the following formula A = L ? W V = A ? t VT = V = V1 + V2 + V3 + Where A = Area L = Length V = Volume W = Width VT = Total volume t = thickness make up the number of bags of cement, and the volume of gravel and sand by multiplying the to tal volume with the factors precomputed for a Class A mixture plus 10% allowance for wastage, thus No. of bag cement = (VT ? 7. 85) + 10% Volume of Gravel = (VT ? 0. 88) + 10% Volume of Sand = (VT ? 0. 44) + 10% Class A mixture has a proportion of 124, that is one part of cement for every two parts of fine coalesce (sand) and four parts of coarse aggregate (gravel). b. Every square meter of a concrete gate uses 6. 0 m. long of reinforcement bar placed at an interval of 0. 25 m. both ways on center. This is equivalent to 1 ? bars at a standard length of 20 feet per bar. The trading floor and toes use the same size of bar, thus No. of reinforcement bar = (Af + 4t) ? 1. 5 Where Af = Area of the floor At = Area of the toes The walls, wings, etcetera use two different sizes of reinforcement bar, thus pic Where Aw = Area of the walls Ax = Area of the wings An = other areas c. Find the total area of a concrete gate by adding all the areas mentioned in (a). await the weight of tie wir e no. 6 by multiplying the total area with a standard value per sq. m. of concrete, thus Weight (kg) = AT ? 0. 3 Kg/sq. m. d. Calculate the volume of boulders needed by multiplying the area of the flooring with the thickness of fill. e. Form impound can be calculated by multiplying the area of walls, wings and bridges by 2. Plywood can also be used as form. Since lumber measurement is still in feet it should be converted into meter, (see conversion table). enforce 2 ? 3 wood for form support. f. Bamboo puno could be calculated from the area of the flooring. A square meter of flooring will require more or less 20 puno staked at an interval of 0. 5 m. both ways on center. This, however, depends upon the hardness of the floor foundation. g. Screens and slabs are calculated based on the design of the concrete gate. h. Assorted nails are calculated based on the thickness of the form lumber used. i. promote cost is 3540% of total material cost. However, close estimates can be computed by determining the cost of labor for the construction and removal of temporary earth dike, excavation of the foundation, staking of bamboo puno, placing of boulders and gravel, construction of forms, concreting of the gate and others. 2. Estimating the cost of construction and installation of a wooden gate. a.Based on the plan of a wooden gate, determine the size and number of lumber for the sidings and flooring. Compute for the total board feet using the following formula pic Where L = Length of lumber in inches W = Width of lumber in inches t = thickness of lumber in inches b. Based on the design and specification of the pillars and braces, compute for the total board feet using once again the above formula. c. Determine the size and number of lumber needed for slabs and screen frames and compute the total board feet. d.Calculate the assorted nails (bronze) based on the lumber used. e. Calculate the coal tar requirement in gallons. f. Calculate the cost of nylon and bamboo s creens. g. Calculate the labor cost at 3040% of the material cost or calculate in detail according to the labor requirement. Calculation includes the construction, painting and installation of the wooden gate and excavation of the floor foundation. c. For the Construction of the Proposed Dikes. Dikes constructed in fishponds vary in sizes. Bigger dikes are, of course, more high-priced to construct than smaller dikes. In other words, the perimeter or main dike will expend more than the secondary or tertiary dikes.The cost of construction is calculated based on the volume of soil filled and generally it costs pic6. 00 per cubic meter. Labor cost, however, depends on the prevailing price in the locality. Transport distance of soil material to the dike is also considered in calculating the cost of construction. keen-sighted transport distance decreases individual output per day and thus will increase construction cost. working(a) eight hours a day, one skilled worker can finish dikin g, using one flat boat, based on the following distances 10 100 meter distance 6 7 cu. m. /day 101 300 meter distance 5 6 cu. m. day 301 500 meter distance 4 5 cu. m. /day d. For the Excavation and Leveling of Ponds. Cost for excavation depends upon the volume of soil leftfield(a) inside the pond after the dikes have been constructed. Considering that some soils have been excavated for diking purposes, only about 60% is left for excavation. Generally, escavation costs about pic2. 00 per cu. m. depending upon the prevailing labor cost in the locality. After excavation, leveling of the pond bottoms follows. This involves the cut-and-fill method (excavation and dumping to low portions).Generally, leveling costs about pic2,000. 00 per hectare. e. For the Construction of Facilities. Facilities include the caretakers house, working shed, bodega, chilling tanks, etc. For proper estimates there should be a simple plan of the facilities. However, rough estimates can be made bas ed on the floor area of a house to be constructed. For a house made of light materials, assume a cost of pic400. 00 per sq. m. floor area and for concrete structures, assume pic1,000. 00 per sq. m. All assumed costs include materials and labor based on 1979 price of materials. f. For the Purchase of Equipment. A fishpond project cannot be operated without equipment.Examples are fish nets, digging blades, shovels, scoop nets, bolos, etc. These items should be included as part of the total development cost. Such equipment should be listed and calculated. g. Contingencies. There should be a contingency fund for unforeseen expenditures, increase of prices and other materials not included in the above calculations. Assume 10% of the above costs for contingencies. 5. 1. 3 Cost estimate For the purpose of determining the cost of developing a new brackishwater fishfarm project, a typical example of a 50-hectare fishpond project applied to the Bureau of Fisheries and Aquatic Resources for a 25-year Fishpond Lease Agreement is presented below. I. Pre-Development 1. For the preparation of feasibility study pic1,000. 00 2. Re-location of boundaries 2,000. 00 3. For the construction of temporary shelter for laborers (light materials) 4,000. 00 4. For the construction of flatboats, 5 units at pic500. 00/unit 2,500. 00 5. For the leverage of small banca, 1 unit at pic600. 00 600. 00 6. For representation and transportation expenses 3,000. 00 Sub-total pic13,100. 00 II. Development Proper 1. Clearing of the area at pic600. 00/ha. (cutting, chopping, burning & removal of logs pic30,000. 00 2. Construction of dikes (filling, compacting and shaping by manual labor) a. Main dike along bay and river 1,920 bilinear meters, 6. 0 m base, 2. 0 m crown and 2. 25 m103,680. 00 height or a total of 17,280 cum. at pic6. 00/cu. b. Main dike along upland, 840 linear meters, 5. 5 m base, 2. 0 m crown, and 2. 0 m height 37,800. 00 or a total of 6,300 cu. m at pic6. 00/cu. m c. Main canal dike, 980 linear meters, 5. 0 m base, 2. 0 m crown, and 1. 8 m height, or a 33,957. 00 total of 6,174 cu. m. at pic5. 50/cu. m d. Secondary dike, 2,540 linear meters, 4. 0 m base, 1. 0 m crown & 1. 5 m height or a 52,387. 50 total of 9,525 cu. at pic5. 50 per cu. m e. Secondary canal dike, 400 linear meters, 4. 0 m base, 1. 5 m crown and 1. 4 m height, or8,470. 00 a total of 1,540 cu. m at pic5. 50 per cu. m f. Tertiary canal dike, 240 linear meters, 3. 5 m base, 1. 5 m crown and 1. 2 m height or a3,600. 00 total of 720 cu. m at pic5. 00 per cu. m g. Tertiary dike, 700 linear meters, 3. 0 m base, 1. 0 m crown and 1. m height or a total7,000. 00 of 1,400 cu. m at pic5. 00 per cu. m 3. Construction and installation of gates a. Main double opening concrete gate, 2 units at pic20,000/unit including labor cost 40,000. 00 b. Construction and installation of 10 units secondary wooden gates at pic3,000. 00 per30,000. 00 unit c. Construction and installation of 15 units tertiary wooden gates at pic1,500/unit 22,500. 00 4. Excavation and levelling of pond bottoms (cut-and-fill) a. Nursery Pond, 1. 5 ha at pic2,000/hectare 3,000. 00 b. Transition Pond, 4. 0 ha at pic2,000/ha 8,000. 00 c. Formation Pond, 8. 0 ha at pic2,000/ha 16,000. 00 d. Rearing Pond, 32. 0 ha at pic2,000/ha 64,000. 00 5. Uprooting and removal of stumps at pic600/ha 30,000. 00 6. For the construction of facilities a. Caretakers Hut made of light materials, 2 units at pic6,000/unit 12,000. 00 b. Bodega, made of light materials for inputs and equipment, 1 unit 5,000. 00 c. Chilling tank with shed, made of light materials 3,000. 00 7. For the purchase of equipment a. Nets for harvesting 3,000. 00 b. Digging blades and carpentry tools 1,000. 00 c. Containers 2,000. 00 8. Contingencies (10% of cost) 52,350. 05 Sub-total pic562,750. 55 T O T A L pic575,850. 55 E STIMATED COST FOR ONE UNIT DOUBLE OPENING MAIN CONCRETE accession I. Cost of Materials Quantity Unit Price Amount 1. Cement 140 bags pic24. 00/bag pic3,360. 00 2. Sand 10 cu. m. 60. 00/cu. m 600. 00 3. Gravel 20 cu. m 80. 00/cu. m 1,600. 00 4. Boulders 8 cu. m 50. 00/cu. m 400. 00 5. Reinforcement Bar a) ? ? ? 20 80 pcs 22. 00/pc 1,760. 00 b) ? 3/8 ? 20 35 pcs 12. 00/pc 420. 00 6. Plywood form 49 pcs 48. 00/pc 2,352. 00 (? ? 4 ? 8) 7. Lumber (S4S) a) 2 ? 2 ? 12 30 pcs 3. 0/bd. ft 360. 00 b) 2 ? 3 ? 12 16 pcs 3. 00/bd. ft 288. 00 c) 1 ? 2 ? 12 10 pcs 3. 00/bd. ft 60. 00 d) 1 ? 12 ? 12 6 pcs 3. 00/bd. ft 216. 00 8. Assorted Nails 10 kgs 7. 50/kg 75. 00 9. G. I. fit 16 20 kgs 8. 00/kg 160. 00 10. Bamboo Puno 400 pcs 4. 00/pc 1,600. 00 Sub-total pic13,251. 00 II. Labor (40% of material cost) 5,300. 00 III. Contingencies (10% of material cost) 1,325. 00 T O T A L pic19,876. 00 say pic20,000. 00 ESTIMATED COST FOR ONE UNIT SECON DARY WOODEN GATE I. Cost of Materials Description Quantity Unit Price Amount 1. Ply Board 1? 10? 14 34 pcs. pic3. 00/bd. ftpic1,190. 00 . 1? 10? 8 3 pcs. 3. 00/bd. ft. 60. 00 2. Slabs 1? 12? 14 2 pcs. 3. 00/bd. ft. 84. 00 3. Pillars and Braces 2? 3? 10 4 pcs. 3. 00/bd. ft. 60. 00 2? 3? 8 7 pcs. 3. 00/bd. ft. 84. 00 2? 3? 14 2 pcs. 3. 00/bd. ft. 42. 00 3? 4? 10 12 pcs. 3. 00/bd. ft. 360. 00 4. Screen Frames 2? 3? 16 2 pcs. 3. 00/bd. ft. 48. 00