Part 1 | ||
Mon | 28/4 | Depart Stirling, to Edinburgh, London, depart for Dhaka. |
Tue | 29/4 | Arrive Dhaka, pm. meet mr. van Zon, Teamleader. |
Wed | 30/4 | Meetings, discussions, in project office, collect background data. |
Thu | 1/5 | FAO office, library data, meet mr. Hoskins, FAO Representative. Contact Dr. Karim, national site selection consultant. |
Fri | 2/5 | Work on background data, prepare material for site visits. |
Sat | 3/5 | Meetings with van Zon, dr. Karim, dr. Ghosh, discussion of BFRS objectives, site visits, selection. Background material. |
Sun | 4/5 | A.m.: preparation of material, p.m.: travel to Jessore, and Khulna, discussion of hydrology data with local Delta Development Project staff. |
Mon | 5/5 | Khulna; collection of local site and area data, irrigation structure/engineering data. Discuss local operation with Pieter Raymakers, project manager Delta Development Project. |
Tue | 6/5 | To Monghla, visit proposed site, also local processing plant, District Fisheries Office. Return to Dhaka. |
Wed | 7/5 | Election Day. Work on data, draft criteria report. |
Thu | 8/5 | Mymensingh, Freshwater Aquaculture Research Station (FARS), discussions Director FRI, van Zon. Return to Dhaka. |
Fri | 9/5 | Work on design aspects. Meeting dr. Karim, specify site and engineering requirements. |
Sat | 10/5 | Work on report draft. |
Sun | 11/5 | Work on report draft. Depart for Rome via Dubai p.m. |
Mon | 12/5 | Arrive Rome, briefing and administrative duties. |
Tue | 13/5 | Depart for London, arrive Edinburgh/Stirling p.m. |
Part 2
Sun | 21/9 | Depart Stirling/Edinburgh for London. Depart for Dhaka. |
Mon | 22/9 | Arrive Dhaka. Initial contact with Hans van Zon, Teamleader, dr. Karim, soil/site selection specialist. |
Tue | 23/9 | To Mymensingh, meet dr. Asadur Rahman, Director FRI, dr. van Zon, discuss objectives, background information. Meet mr. Patwari, executive engineer, discuss engineering requirements and building procedures for brackishwater site. To Dhaka, meet dr. Karim, discuss site details. |
Wed | 24/9 | Dhaka, prepare site data, plan collection of fuller data. Arrange site works. Preliminary design work, layout, ponds, water supply. |
Thu | 25/9 | Dhaka. Preliminary design work, estimation of quantities. |
Fri | 26/9 | Preliminary design work, hatchery, buildings, services. |
Sat | 27/9 | To airport for Jessore, cancelled due to severe flooding. Rearrange schedule with dr. Karim and mr. Patwari; p.m. work on design and information. |
Sun | 28/9 | Meeting at project office with dr. Karim, mr. Patwari, discuss outline design, plans for site visit. |
Mon | 29/9 | To airport for Jessore. flights cancelled. Rearrange plans. Draft local consulting engineers terms of reference. |
Tue | 30/9 | Project office. Project design discussions dr. Karim, mr. Patwari. Finalization local consultants requirements. Further design/quantification work. |
Wed | 1/10 | Project office. Design specifications, approximate development budget. Time-tabling. Review consultant tender documents. |
Thu | 2/10 | Project office. Water supply and treatment details. |
Fri | 3/10 | Sluice channel, volume details. Preliminary budget. Draft consultant tender documents. |
Sat | 4/10 | To Jessore, by road to Khulna, meet Soils Research Staff, PWD executive engineer. P.m. to Paikgacha, arrive evening. |
Sun | 5/10 | Visit site, walk round perimeter areas, discuss areas required with local upazilla staff. Obtain local ownerships maps, additional survey data. Return to Khulna late p.m. |
Mon | 6/10 | To Jessore, fly to Dhaka. Work on design revisions, preparation for briefing FRI staff. |
Tue | 7/10 | To Mymensingh, discuss site/design plans with dr. Asadur Rahman, director FRI, and dr. van Zon, teamleader; decide on critical project timing. Return Dhaka p.m.; prepare equipment lists. |
Wed | 8/10 | Meeting project office with dr. van Zon, dr. Karim, review site/design needs. Prepare more site drawings. Organize visa. |
Thu | 9/10 | Project office, prepare project material. Meeting Permanent Secretary, Mr. M.A. Syed, Ministry of Fisheries and Livestock discuss project status, critical decisions. Meeting Mr. Walter Kock, World Bank, regarding budget, tender regulations. Further project preparation. |
Sat | 11/10 | Final drawings, presentation material for FRI Board of Governors meeting. Project descriptions for engineering consultants. |
Sun | 12/10 | Discussions dr. van Zon, project design, report preparation etc. Final work. Depart for Rome p.m. |
Mon | 13/10 | Arrive Rome. Briefing and administrative work. |
Tue | 14/10 | To UK a.m.; arrive Edinburgh/Stirling p.m. |
Persons met
Mr. | M.A. Syed, Permanent Secretary, Ministry of Fisheries and Livestock, Government of Bangladesh, Dhaka |
Dr. | Asadur Rahman, Director FRI, Mymensingh |
Dr. | J.C.J. van Zon, Research Planning Advisor/Teamleader, FAO/UNDP Project BGD/83/010, Dhaka |
Mr. | J.A. Hoskins, FAO Representative, Dhaka |
Mr. | Walter Kock, Agricultural Development Adviser, World Bank, Dhaka |
Dr. | John Halver, Fish Nutrition/Feed Technology Consultant, FAO/UNDP Project BGD/83/010 |
Dr. | Mahmudul Karim, Shrimp Culture Adviser/Soil Specialist, FAO/UNDP Project BGD/83/010, Dhaka |
Mr. | Pieter Raymaker, Development Engineer, Delta Development Project, Khulna |
Dr. | A.N. Ghosh, Shrimp Specialist, FAO/UNDP Project BGD/83/010 |
Mr. | Md. Ali Akbar Patwari, Executive Engineer, FRI, Mymensingh |
Mr. | Shamsuddin Ahmed, Dep. Director of Fisheries, Khulna Division |
Mr. | Kahlilar Rahman, Executive Engineer, Khulna Division, Khulna |
Mr. | Abul Kalam, Soils Resources Development Institute, Khulna |
Mr. | Chatur Krishna, Fisheries Officer, Khulna Division |
CULTURE SECTION
RESOURCES SECTION
REPRODUCTION SECTION
HEALTH CARE SECTION
PROCESSING SECTION
GLOSSARY:
Units: | Bigha | = | 0.134 ha |
Seer | = | 0.933 kg | |
Maund | = | 40 seers | |
Crore | = | 10*7 written 1,00,00,000 | |
Lakh | = | 10*5 written 1,00,000 | |
Other terms: | Baor | = | oxbow lake, isolated from river by change in course |
Beel | = | small, low lying depression on a floodplain, sometimes drying up in the dry season | |
Haor | = | large, low lying depression on a floodplain, part of which dries during the dry season. Individual beels may be found as water level drops | |
Polder | = | area of low-lying land reclaimed from inundation by building of dikes | |
Boro | = | rice crop planted Nov/Dec, harvested April/June | |
Aman | = | rice crop planted May/June, harvested Nov/Dec | |
Aus | = | rice crop planted Feb/march, harvested June/July | |
Bheri | = | system for simple extensive fish and shrimp culture, using tidal water exchange and wild seed | |
Gher | = | local name for shrimp farm area | |
Goi | = | harvesting device for shrimps, screened catchment basin connecting to main water control gate | |
River | = | waterway > 100 m wide | |
Gang | = | " > 50–100 m wide | |
Khal | = | " < 50 m wide | |
Creeks, canals | = | smaller waterways | |
Species: | Badga chigra | = | Penaeus monodon |
Chapra | = | Penaeus semisulcatus | |
Horina | = | Metapenaeus monoceros | |
Golda changri | = | Macrobrachium rosenbergii |
Table C1 - Brackishwater aquaculture production, growth in area. Based on Aquatic Farms, 1985
Satkhira | Khulna | Bagerhat | Cox's Bazar | Total | |
1983 | 8,000 | 12,800 | 11,000 | 18,700 | 50,500 |
1990 | 22,000 | 17,300 | 25,000 | 31,700 | 96,000 |
2005 | 34,000 | 30,300 | 25,000 | 45,700 | 135,000 |
Average growth 15% per year, 27% in Khulna. | |||||
Approx. 3100 farms, 52,000 ha; in 1984 Khulna 61.4 %, and Chittagong 37.7 %. | |||||
Estimate 1984/85: 72,000 ha |
Table C2 - Projects in brackishwater aquaculture development
Organization | Development |
ADB/DOF | Demonstration centres 4–10 ha. Up to 150 farms. Farm shrimp areas: Khulna, Satkhira, Bagerhat, Cox's Bazar |
Fry handling centres: uppazilas of Debhata, Kohgang, Shanrogar, Mongla | |
Total $ 37.6 million, of which $ 20 million for farms. | |
DOF | 1,695 ha, Rangur, Cox's Bazar, 41 farms of 40 ha, now divided into 3. |
ADB | Adjacent area, 1700 ha |
WB/DOF | FRI system, rationalize and strengthen R + D capability in fisheries and aquaculture. Includes present development. |
Table C3 - Significance of brackishwater production
Activity | Approx. Tk×10/6 value | Priority | |
1985 | 2005 | ||
Riverine production | 14,320 | 15,000 | 1 |
Marine fish | 4,680 | 5,000 | 3 |
Small freshwater ponds | 3,290 | 10,000 | 2 |
Brackishwater production | 540 | 15,000 | 1 |
Larger freshwater bodies | 120 | 1,000 | 4 |
Freshwater pen/cage | - | 1,000 | 3 |
Mariculture | - | 500 | 5 |
Up to 250,000 t production may be lost with the foreseen 1.7 × 10*6 ha reduced aquatic habitat under changed land use |
Table C4 - Soil texture, pH, and nutrient status at Paikgacha site
SOIL TEXTURE, pH, AND NUTRIENT STATUS AT NORTH SHIBERBATI (PAIKGACHA) SITE*1
Step no | Soil depth (cm) | %Sand US | %Silt US | %Clay | Texture | pH | O.M. % | SS/AA | Ca | Mg | NH4-N | P | S | B | Cu | Fe | Mn | Zn |
meq/100ml or ug/ml | ||||||||||||||||||
12/48 W 239 | 0– 15 | 5 | 41 | 54 | 7.1 | 1 | 0 | 9.9 | 6.7 | 5 | 9 | 67 | 1.7 | 12 | 99 | 11 | 1 | |
15– 30 | 10 | 36 | 54 | 8.0 | 0.9 | 0 | 10.4 | 6.7 | 3 | 7 | 54 | 1.7 | 7 | 36 | 4 | 1 | ||
30– 45 | 2 | 45 | 53 | 8.1 | 0.57 | 0 | 10.3 | 6.6 | 2 | 5 | 56 | 1.5 | 5 | 41 | 4 | 1 | ||
45– 90 | 31 | 26 | 43 | 8.1 | 0.57 | 0 | 11 | 6.8 | 10 | 19 | 52 | 1.0 | 14 | 131 | 22 | 1 | ||
90–140 | 9 | 29 | 62 | 7.9 | 1.3 | 0 | 12.1 | 6.8 | 6 | 13 | 54 | 1.3 | 13 | 64 | 9 | 1 | ||
140–200 | 27 | 16 | 57 | 8.0 | 0.7 | 0 | 11 | 6.8 | 10 | 19 | 52 | 1.0 | 14 | 131 | 22 | 1 | ||
13/48 W 239 | 0– 15 | 3 | 46 | 51 | 8.0 | 1.0 | 0 | 10 | 6.6 | 9 | 9 | 61 | 1.7 | 9 | 83 | 10 | 1 | |
25– 47 | 5 | 56 | 39 | 8.1 | 0.47 | 0 | 10 | 6.5 | 6 | 3 | 94 | 1.3 | 8 | 69 | 13 | 1 | ||
47– 55 | 5 | 42 | 53 | 8.0 | 0.9 | 0 | 11.4 | 6.7 | 8 | 5 | 69 | 1.2 | 12 | 69 | 17 | 1 | ||
55– 70 | >1 | 55 | 45 | 7.8 | 1.4 | 0 | 10.4 | 6.5 | 9 | 7 | 76 | 1.1 | 6 | 81 | 15 | 1 | ||
70–100 | >1 | 25 | 75 | 8 | 0.9 | 0 | 16.4 | 7.1 | 6 | 3 | 82 | 1.7 | 13 | 109 | 14 | 1 | ||
100–115 | 14 | 27 | 59 | |||||||||||||||
14/48 W 239 | 0– 10 | 8 | 51 | 41 | SiC | 8 | 0.9 | 0 | 8.6 | 5.7 | 7 | 9 | 46 | Tr | 5 | 138 | 10 | 1 |
10– 30 | 60 | 6 | 34 | 8.1 | 0.1 | 0 | 4.2 | 3.3 | 8 | 6 | 30 | Tr | 2 | 131 | 9 | 1 | ||
30– 45 | 47 | 34 | 19 | 7.8 | 0.9 | 0 | 9.4 | 4.3 | 10 | 3 | 56 | 0.7 | 2 | 97 | 11 | 1 | ||
45– 80 | 6 | 56 | 38 | 8 | 0.1 | 0 | 6.2 | 4.8 | 7 | 5 | 25 | Tr | 2 | 115 | 12 | 1 | ||
80–100 | 26 | 46 | 28 | 8 | 0.9 | 0 | 8.6 | 5.7 | 7 | 9 | 46 | Tr | 5 | 138 | 10 | 1 | ||
100–120 | 7 | 22 | 71 | 6 | 1.6 | 0 | 9.8 | 7 | 16 | 3 | 66 | 1.2 | 14 | 134 | 13 | 1 | ||
15/48 W 239 | 0– 18 | 1 | 44 | 55 | 6.9 | 1.3 | 0 | 7.8 | 6.7 | 15 | 6 | 86 | 1.4 | 14 | 176 | 17 | 1 | |
18– 30 | 1 | 46 | 53 | 6.9 | 2 | 0.3 | 7.8 | 6.9 | 21 | 7 | 94 | 1 | 18 | 318 | 48 | 3 | ||
30– 60 | 1 | 47 | 52 | 5.8 | 2 | 0.5 | 7.9 | 6.8 | 20 | 8 | 83 | 0.8 | 14 | 178 | 17 | 1 | ||
60– 90 | 32 | 17 | 51 | 7.2 | 1.9 | 0.6 | 8.5 | 6.6 | 10 | 13 | 92 | 0.7 | 21 | 346 | 44 | 4 | ||
130–170 | 7 | 34 | 59 | 7.4 | 1.7 | 0 | 14 | 7.4 | 10 | 6 | 90 | 2.7 | 8 | 138 | 112 | 7 | ||
170–200 | 5 | 34 | 61 | 7.3 | 1.9 | 0 | 8 | 7.0 | 5 | 4 | 94 | 1.2 | 14 | 183 | 32 | 1 | ||
17/48 W 239 | 0– 18 | 2 | 13 | 55 | 7.8 | 1.0 | 0 | 10.1 | 6.8 | 5 | 2 | 63 | 1.4 | 12 | 73 | 14 | 1 | |
18– 33 | 40 | 5 | 55 | 6.8 | 1.9 | 0 | 10.8 | 7.1 | 3 | 8 | 87 | 1.8 | 21 | 128 | 30 | 2 | ||
33– 90 | 16 | 29 | 55 | 7.2 | 2 | 0 | 10.3 | 7.1 | 10 | 5 | 113 | 2.7 | 15 | 145 | 24 | 2 | ||
90–115 | 35 | 6 | 59 | 7.3 | 1.9 | 0 | 16.2 | 7.4 | 12 | 4 | 106 | 2.3 | 15 | 88 | 28 | 2 | ||
115–120 | 9 | 7 | 84 | 7.3 | 2.1 | 0 | 11.1 | 7.2 | 15 | 5 | 108 | 1.7 | 10 | 79 | 110 | 7 | ||
18/48 W 239 | 0– 15 | >1 | 45 | 55 | 7.3 | 1.5 | 0 | 8.2 | 6.8 | 6 | 5 | 94 | 2.1 | 15 | 146 | 19 | 1 | |
15– 40 | 2 | 47 | 51 | 7.9 | 1.4 | 0 | 7.6 | 6.3 | 2 | 4 | 83 | 1.5 | 9 | 100 | 12 | 1 | ||
40– 55 | 1 | 48 | 51 | 8.0 | 0.8 | 0 | 11.8 | 6.9 | 3 | 4 | 89 | 1.4 | 14 | 150 | 22 | 2 | ||
55–100 | 15 | 38 | 47 | 7.8 | 0.9 | 0 | 13.3 | 6.6 | 3 | 4 | 97 | 2 | 9 | 99 | 10 | 1 | ||
110–160 | 1 | 41 | 58 | 7.7 | 0.9 | 0 | 9.8 | 6.5 | 7 | 7 | 61 | 1.4 | 12 | 158 | 24 | 1 |
A Initial calculations of excavation volumes and level constraints
Initial assumptions based on average height of 0.9 m.
Total site dimensions (based on 100 ft grid (30.5 m)): 825 m length by 1000 ft = 305 m width → 251,625 m2, say 250,000 m2.
Area of creek, based on survey: approx. 100 × 2700 ft: 35 × 850 m = ± 30,000 m2; average height + 0.25 m.
Thus total volume, above 0.0 m (datum) is: (250.000 m2 – 30.000 m2) × 0,9 plus (30.000 m2 × 0,25 m) → 198,000 m3 + 7,500 = 205,500 m3.
This volume changes by (250.000 m2 × 0,1) → 25,000 m3 for every 0.1 m change in base level.
Some level constraints:
Maximum site levels: + 3.0 m, high tide. Height of embankment is 4.27 m.
Low tide - 1.46 m minimum; max low tide + 0.1 m, min HWL 1.17 m
Thus minimum filling tide level is + 1.17 m. Minimum spring tide level is approx. + 2.0 m. Maximum spring low tide level is approx. - 0.80 m.
Level of acid layers in samples between 30–90 cm below surface. The 90–120 cm layer is apparently OK. Thus critical levels are approx. from 0.000 to 0.600 m below datum.
Check scales and dimensions:
1.10.000 : 1 cm → 100 m - small diagram is out of scale. Note main wall crest dimensions 14' wide 1:2 inside slope, 1:3 outside. Area is thus redrawn at defined scale, based on OS maps (see site layout diagrams).
Approximate wall volumes required:
Base on 65 % duplication factor (i.e. individual pond wall volumes are reduced to 65 %, as many walls are in common).
Large ponds = 3×1 ha, say 60×165 m; with perimeter = 490 m,
typical cross section 3 m,
1.2 1.5 1:2 = 9 m2 → (3 × 490 × 9) × 65 = 8600 m3
At 2 m crown = 7200 m3; at 1 m = 5750 m3.
Intermediate ponds = 9 × 0.5 ha, say 40 × 125 m, perimeter = 330 m, typical cross-section = 2 m: 7.5 m2, 1 m: 6.0 m2
2 m (9 × 330 × 7.5) × 0.65 = 14,500 m3
1 m (9 × 330 × 6.0) × 0.65 = 11,600 m3
Smaller ponds = 18 × 0.2 ha, say 30 × 65 m, perimeter = 190 m,
2 m crown → 16,700 m3,
1 m crown → 13,350 m3.
If these ponds are excavated, volumes are 54,000 m3 (c), 40,500 m3 (d).
Experimental ponds: 27 × 0.1 ha, say 20 × 50 m, perimeter=140 m, 1 m crown →14,750 m3, 0.5 m crown → 8,600 m3.
Area for building platform: assume 10,000 m2 with additional 1 m buildings →10,000 m3.
Matching of system volumes, definition of levels:
Total volume required - initial assumptions, wide walls. 8,600 m3 + 14,500 m3 + 16,700 m3 + 14,750 m3 + 10,000 m3 → 64,550 m3.
If this is taken from actual pond area, (3×1)+(9×0.5)+(18×0.2)+ (27×0.1) → 138,000 m2 → 0.46 m overall lowering pond floors.
Note that this is too much for acidic areas.
Note that at the given site levels the ponds could be operational at existing level, with walls e.g. @ + 2.50 m, as critical HWL is 2.00 m. This would permit filling to approx. 0.8 m above the floor level.
If smaller ponds are in fact completely dug out, in areas away from acid zones, they would generate 94,500 m3, which would be quite ample for needs.
Checking cost:
Assuming a factor of 1.5 on PWD rates for in situ cut/fill cost, to allow for some site movements, based on a movement of say 65,000 m3 at standard cost. 18 Tk/m3 → 1.755 × 10*6 Tk.
Note present allocation for pond construction is 2.98 × 10*6 Tk. There is also a budget allocation for site development. There is thus on initial estimates an adequate provision.
B Assessing water flows in main supply channel and sluice gates
Assumptions:
On the basis of 1 m pond depth, pond area 138,000 m2, quantity required is 88,320 m3 per filling cycle.
Sluice gate design:
Using Katoh's grapical method, with modifications to create ‘sluice factor’ for more rapid estimations.
This is based on estimating flow through the sluice during successive time intervals, here 1 hour, where outside level (tide) is higher than inside (pond or channel) level. The interior level rises as the flow continues. The relationship depends on the area of interior covered by the incoming water. The basic equation is:
Vol = 1.7 uB he*1.5 dT.
Thus where width = 2 m, u = 0.91, dT = 3600 secs:
V = 1.7 × 0.91 × 2 × 3600 × 0.31*1.5 = 1.920 m3.
Area to be covered is 110,400 m2. Hence change in interior level = 0.017 m.
Notes (see Figure in main report):
Tidal curve peak must exceed maximum fill height of ponds, usually by 0.2–0.3 m to allow for system head losses. Note also number of effective tidal hours in cycle in which filling possible. If pond base is high, this may be reduced to 3–4 hours; here it is approx. 5 hours.
Draw V-h line first. As starting approximation first hours input should be approx. V/No of cycles × average no of hours per cycle × 2 (tidal range factor - first period usually slow).
The calculations can be done more rapidly by using a sluice factor, Fs = 1.7 uB Dt, thus V = Fs × he*1.5.
Use formula to select ‘sluice factor’ of approximate size.
Sluice factors = (Dt = 3600 secs, hr) = 1.7 u BDT, u = 0.91.
B = 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Fs = 2,785 5,570 8,354 11,138 13,923 16,708 19,492 22,277
B = 4.5 5.0 5.5 6.0
Fs= 25,061 27,846 30,631 33,415
Thus, with 110,400 m3 volume in 1 metre pond depth, filling with 3 tidal cycles with average 5 effective hours per cycle →± 7,300 m3/hr.
On this basis with the avge = 0.5 m, he*1.5 is approx. 0.35; Fs should be 7,300/0.35 → 21,000 m3 in or ± 3.5–4 m wide.
Note there are no corrections for changing tidal amplitudes over say 3–4 tidal cycles, though this should not be significant at the level of precision involved. As presently defined an ‘averaging’ approach does not represent conditions accurately if the gate is narrow as internal levels do not equilibrate evenly throughout the cycle.
To recalculate, as this gate size is relatively wide:
Say allow 4 cycles , average 4.5 hrs => 18 hrs, use an additional factor of 1.25 (Depends on the point on the tidal curve as in most cases ponds only starts filling in the mid-tide state, where tide use is relatively rigid).
Thus 110,400 m3 / 18 × 1.25 → 4,910 m3/hr, which predicts ± 3 m. This calculation is reexamined in more detail later.
Return of the method to check 3 m wide sluice:
T1-To, d, av = 1/2 (h1-hO) = 1/2 (0.62 – 0) = 0.31;
Voll = 1.7 uB he*1.5DT, width 3 m, h = 0.91, DT = 3600 sec.
Do this on the assumption equation is actually Q = 1.7 uB he*1.5 m3/sec, where he is difference between avge external and avge internal levels over the hour.
Thus Tl - TO average external level is 1/2 (0.62 + 0) = 0.31.
Average internal level, assuming approx. 20 hrly stages of filling
is 1/2 (0.05 – 0) = 0.025 m (this can be checked later against
actual-flow in during the period).
Thus Q = 4.64 × (0.31 – 0.025)*1.5 = 0.706 m3/sec.
Flow in 1 hr = 2541 m3/0.0125.
Thus actual rise is 0.025 m.
In second hour h ext = 1/2 (0.95 + 0.62) = 0.785 m.
With internal level at, say, 0.05 m, Q = 4.64 × (0.735)*1.5 = 2.92
m3/sec.
In 1 hr = 10,526 m3, rise by end of hr 2 is 10 cm.
Thus actual median level is 0.04 m. Level at the end of the hour is
12.5 cm, =± 13 cm.
Third hour, h ext = ± 0.96 m, internal level @ say 0.18 (0.13 +
0.05) hr, Q = 4.64 × (0.78)*1.5 = 3.2 = 11.510 m3.
Rise by end hr 3 is 11.5 cm; level is 24.5 cm; 0.245 m.
Fourth hour h ext = 1/2 (0.95 + 0.65) = 0.80 m, internal level at 0.3 m, Q = 4.64 × (0.5)*1.5 = 5,900 m3/hr → 0,059 m => 0.304. (actually 0.28 = 6,250 m3/hr → 0.063 m => 0.308).
Fifth hour = 1/2 (0.65 + 0.2) = 0.425 m, internal level 0.33 m, Q = 4.64 × (0.095)*1.5 = 489 m3/hr → 0.005 m → 0.313.
NB: as this is actually less than 1 full hour the fill is ± 0.31 m.
T4 → T5 h ext = (0.31 + 0.62)1/2 = 0.465 m, h int = 0.31 m;
Q = 4.64 × (0.155)*1.5 = 566 m3 → 0.006 0.361 m.
T5 → T6 h ext = 0.785 m, internal level = 0.33 m;
Q = 5,130 m3 → 0.37 m.
T6 → T7 h ext = 0.96 m, h int = 0.40 m;
Q = 7,000 m3 = 0.07 m → 0.44.
T7 → T8 h ext = 0.80 m, h int = 0.46 m;
Q = 3,310 m3 = 0.03 m → 0.47.
Estimate T8' as 0.50. Thus:
T8' - T9 h ext = 0.56 m, h int = 0.50, DT = 1200 = 81.8 m3 = 0.008
fill → 0.51 m.
T9 - T10 h ext = 0.785 m, h int = 0.53 m, Q = 2150 m3 → 0.02 m
fill → 0.53 m.
T10 - T11 h ext = 0.96 m, h int = 0.55 m, Q = 4390 m3 → 0.044 m
fill → 0.0574 m.
This would give about 0.6 m by the end of the tidal cycle. On this trend it would require some 5–6 tides to fill the ponds completely, as subsequent tidal cycles provide less head difference between inside and outside.
Conclusions:
A sluice gate of 3 m width is just sufficient to allow exchange of approx. 80 % of water volume to depth of 0.8 m above a pond base of l m above datum, during poorest tides. This would be amended by:
Having less stringent water exchange requirements;
Increasing gate width;
Lowering pond base level.
C Layout aspects
Shape of site means long supply channel - note volume of material created, and possibly required for wall.
Primary layout selected (see figure in main report) gives relatively efficient water supply system, but does not give chance to spread experiments across a range of soils.
Could have alternative layout, with ponds grouped in modules along the length of the long axis, i.e. each module would have 1 × 1 ha pond, 3 × 0.5 ha ponds, 6 × 0.2 ha ponds, and 9 × 0.1 ha ponds. This has the disadvantage of variable distance between laboratories and ponds for ponds of similar type.
Pond sizes, approximately (nominal sizes):
1 | ha | (3) | 60×160 m |
0.5 | ha | (9) | 40×125 m |
0.2 | ha | (18) | 30× 65 m |
0.1 | ha | (27) | 20× 50 m |
Pump location alongside main gate, with feed to channel. Secondary pumps from inner channels to laboratory/storage.
Access/main road along supply channel wall, with access to main wall, plus at least one bridge to pond area.
Building location: site guesthouse + ‘B’ accommodation units together. Multistorey buildings in separate area, probably in north-east area of site. Other laboratory buildings grouped together, preferably near ponds.
D Design: water supplies
Main water supply to farm: see also sluice gate design. Max. inlet flow required 110,400 m3 over 15 tidal hours.
Assuming channel material has limiting velocity of 0.5 m/sec and minimum flow is 1 1/2 × average flow → 11,040 m3/hr, or 3.05 m3/sec.
For limiting velocity to be acceptable, CSA = 6.1 m2.
On the basis of slope available, say 0.1 m drop in 800 m to interior of site, with channel, e.g. 1:1 side slopes, D/b ratio 0.2 using formula:
Q = K/n D*8/3 S*1/2, K = 5.03, n=0.03
3.05 – 5.03/0.03 D*8/3 × 0.011 (S = 0.1/800); thus D*8/3 = 1.65.
D = 1.202 m; b = 6.0 m.
The area of this section is approx. 8.6 m¾ which is acceptable, but depth is excessive. Thus if D is 0.5 m, b would be approximately 12 m, which is also excessive.
The next approach would be to increase limiting velocity; for clay loams this could increase to ± 1 m/sec. Hence CSA = 3.1 m2 Using a value of S of 0.2/800, S 1/2 = 0.0158, D = 1.05, b = 5.3 metres. On the basis of D = 0.8 m, b would be ± 7 m. CSA would be ± 6.67 m2, 6.24 m2 respectively.
Checking with most efficient channel slope criteria; with side slope 1:1, b = 0.828D, which does not correspond with above relationship. It will thus be necessary to recheck.
Returning to actual inlet flow conditions, to check most critical conditions; maximum flow is actually ± 15,000 m3/hr, but external water level is about 1 metre, with pond level ± 0.18 m. Thus the likely Dh in the system could be as much as 0.4 along the channel; S = 0.0005; S1/2 = 0.0223. Thus with 15,000 m3/hr:
Q = 4.167 = 5.03/0.03 D*8/3 × 0.022;
D*8/3 = 4.167/3.689 = 1.13; D = 1.047 m, b = 5.2 m.
This channel can be further improved by dropping the channel grade slightly towards the end; thus with 0.2 m fall on channel floor, S = 0.6/800 m, S*1/2 = 0.0274, D*8/3 = 0.9197, D = 0.97, b = 4.85 m.
Using traditional channel formula, with D = 0.8 m; b = 5.0 m to check above.
V = 1/n R*2/3 S*1/2 = 1/0.03 × 0.742 × 0.0274 = 0.678 m/sec, where a = 0.8 2 + 0.8 2 = 1.13.
R = CSA/WP = bD + D2/b + 2a = 4.64/7.26 = 0.639.
Thus Q = V × CSA = 3.144 m3/sec.
Thus width needs to be increased 50 %.
Finally, a compromise can be sought by starting with a wide channel, reducing as the large 1 ha, 0.5 ponds are passed.
Alternative, pipe culvert sluice.
Checking water flow through sluice with concrete culvert design, using smaller tidal profiles. Use 3× 1 m drain pipes.
In the first hour, Ho = 0.31 m, Hi = 0.03 m; H = Ho - Hi = 0.28 m. Q = (2.093D2 HO.5) × 3 pipes = 3.32 m3/sec.
Using channel flow approach:
V = 1/n R*2/3 S*1/2; S = 0.2 m on 20 m length = 0.01; S*1/2 = 0.1; V = 1/0.03 × 0.31 × 0.1 = 1.027 m/sec.
Q = 1.027 × 0.198 m2 = 0.203 m3/sec; with 3 pipes → 0.61 m3/sec.
With S = 0.20/10 m → S*1/2 = 0.14; 3 pipes → 0.86 m3/sec.
Using smoother ‘n’ value, e.g. 0.25, flow → 1.03 m3/sec; thus flow into ponds ± 3708 m3, level inside is 0.037 m.
In second hour of filling, Ho = 0.70 m, Hi = 0.20 m, area = 0.6 m2, WP = 1.98 m, R = 0.3 m, S = 0.60/10 m, S*1/2 = 0.245; V = 1/0.025 × 0.449 × 0.245 = 4.40 m/sec, Q = 2.64 m3/sec, total Q = 7.91 m3/sec = 28,463 m3 over one hour; increase of interior level is 0.285 m.
In the third hour, Ho = 0.96, Hi = 0.40, V = 1/0.025 × 0.63 × 0.237 = 5.96 m/sec; Q = 4,68 m3/sec, Qt = 50,558 m3/hr, increase in level is 0.506 m, taking overall level to 0.826 m.
Conclusion: this system is probably more accurate than other approaches, with modification of Dh figures to allow for channel, will give better approach to the sluice problem.
Reappraisal of channel widths-optimizing size.
The system is still limited by channel width and depth. Considering actual layout, the 1.0 ha ponds require about 22 % of total flow, 0.5 ha ponds require ± 32 %, 0.2 ha ponds ± 25 %, 0.1 ha ± 20 %.
Thus the first section takes 24,000 m3 per fill, leaves 87,000 m3.
Second section takes 36,000 m3, leaves 51,000 m3.
Third section takes 29,000 m3, leaves 22,000 m3.
Using say 6 m channel width, depth 0.4 for first section: Vc = 1.5 m/sec → 12,960 m3/hr, reduce to 4 m for next section, depth 0.4 → 8,640 m3/hr, then 3 m for next section, depth 0.3 → 4,860 m3/hr.
This could permit the original flows; in fact by deepening the supply channel slightly, e.g. by 0.2 m, still drainable by setting the sluice about 0.2 m lower down, Qa = 19,440 m3/hr, Qb = 12,960 m3/hr, Qc = 7,290 m3/hr. This would create a slight hydraulic jump at the inlets to secondary channels, which would increase head loss slightly, but would probably be tolerable.
Note: checking hydraulics: at Q = 15,000–20.000 m3/hr, Dh across sluice is likely to be only ± 0.1 m, thus during the maximum flow period, the channel will fill relatively quickly, and will be quite deep. Thus a working depth of 0.8–1 m, used to calculate channel velocities will be acceptable.
Rerunning the calculations at 60 % exchange of entire pond area gives peak requirement → 8,300 m3/hr, which would require a cross sectional area of 1.5 m2, which if at depth 0,4 m, would require a channel width of 3.35 metres. Thus the channel could be narrowed if a lower exchange were acceptable. Over the channel length, this would require a gradient of 0.35 metres. The gradient would be reduced to 0.16 m at a channel width of 6 metres.
Provision of silting basin:
If silt particles are to be removed: Vs = 10-3 -10-1 cm/sec, assuming Ps = 2.5, with particle sizes 0.0006- 0.06 mm. At smallest particle size, Vs = Q/A, where Q = 10,000 m3/hr or 2.8 m3/sec. 10-5 = 2.8/A; A = 2.8 × 10*5 m2 = 28 ha.
For larger particle sizes, 0.001 m/sec, A = 2,800 m2.
If a section of channel is used, e.g. at sluice area, say 20 m basin, this would be 140 m in length.
An alternative would be to settle material out in a silting zone before the inlet sluice, though it could be difficult to avoid resuspension.
A further though less acceptable alternative would be to use alternate ponds to collect silt, possibly to flush out during monsoon periods.
Pumping capacity:
Assume a similar overall requirement, i.e. 60 % of replacement, 8,300 m3/hr; at operating level of 2 m, thus requires ± 95 HP. However as pumping could be done throughout the tidal cycle, particularly during deep tides, this could be reduced further to ± 50 HP. This would be provided by 2 or 3 pumps normally; direct diesel pumps would probably be most suitable. In initial stages, pumping would probably only be supplementary, and for partial use. Thus the initial size could be as little as 10 HP.
Note: supply channel volume is approx. 800×3×1 m → 2400 m3, which would require ± 3 hours pumping at this capacity before much of the ponds could start to be filled.
Freshwater runoff from site:
Assuming peak rainfall intensity of approx. 300 mm/24 hours, 30 mm/hr, maximum water input, assuming ± 20 % runoff from surrounding walls, etc. would be ± 16.56 ha × 0.03 m → 4968 m3/hr. At this ratio, 100 mm of rain raises pond levels by 120 mm. If ponds are near full, much rainfall can overflow into the waste channels (see later). If e.g. 3 days rain of 600 mm occur, this would dilute pond water very significantly (even more so if floodwater entered the site).
Sizing secondary channels:
First channel supplies 3 × 1 ha ponds → 3.0 ha, assume 80 % exchange water within 12 tidal hours, thus → 2.000 m3/hr → ± 0.55 m3/sec.
Using a channel of b = 3 m, D = 0.3, A = 0.99 m2, V = 0.56 m/sec = 1/0.025 R2/3 Sl/2; Sl/2 = 0.025 × 0.56/0.4046; S = 0.001197.
Channel length is approx. 200 m, thus requiring 0.24 m Dh.
With a 2 m channel, A = 0.69 m2, V = 0.797 m/sec = 1/0.025 × 0.414 × 5 1/2, S*1/2 = 0.025 × 0.797/0.389 => 0.0512, S → 0.00262. Thus Dh = 0.525 m.
Allowing a fall of 0.1 % => 0.2 m Dh at channel base, this requires ± 0.32 Dh. This channel size (2 m) will probably be adequate, as flows will reduce significantly beyond the first 50 – 100 metres.
Second channel supplies 9 × 0.5 ha ponds → 4.5 ha. Sized as above → 3000 m3/hr → 0.833 m3/sec.
Where b (width) = 3 m, D = 0.3, A = 0.99 m2, V - 0.84 m/sec; S*1/2 = 0.025 × 0.84/0.4046 → 0.0519; S = 0.00269. Thus Dh @ 200 m = 0.539 m.
Where D = 0.4, A = 1.36 m2, V = 0.61 m/sec; S*1/2 = 0.025 × 0.61/0.0477; S = 0.00122, Dh = 0.20.
Third channel supplies 18 × 0.2 ha → 3.6 ha, sized as before → 2400 m3/hr. A 3 m channel will be more than adequate.
Fourth channel supplies 27 × 0.1 ha → 2.7 ha. Additional flow may be required from this channel to supply the main buildings. The channel is therefore also sized at 3 m.
Drainage channels:
Main drainage: use will be made if possible of the existing khal, which is more than sufficiently sized. As the level of this is considerably lower than that of the ponds, it will be possible to increase average gradients subject only to channel limiting velocities. Using similar criteria to these above:
First channel, 6,000 m3/hr, V1 = 1.5 m/sec, CSA = 1.11 m2; at D = 0.8 m, b = 0.6 m, say 1 m width, thus 1.5 = 1/0.025 × 0.58 × S*1/2; S*1/2 = 0.0646; S = 0.0042. Thus over 300 m length drop is 1.25. In practice, channel could be widened, to limit risk of intermittent scouring.
Other channels can be sized similarly.
E Recheck volumes/fill, etc.
Volume required for main external wall, at 820 m × 2.5 m height @ slope 1:2, crest width 3 m; CSA = (3+5) × 2.5 → 20 m2. Thus volume required is 16,400 m3.
Assuming a maximum borrow-pit of 1.25 metres, with limit of 80 % of usable length (i.e. spacing between each borrow-pit and nominally vertical walls at pit edges), fill available per metre pit width along the 820 m length is 820 m3. Thus 20 metre pit width is required for 16,400 m3 fill volume.
For the internal channel wall volume required = s 8.5 m2/metre. Fill available form excavating channel to 0.5 m below grade is 3 m2/metre. Based on an 800 m length, fill required is (8.5 - 3) × 800 → 4,400 m3, which would require a further ± 5 m pit width.
Secondary supply channel: 1 ha ponds, 0.5 m below grade, 250 m length, 3 m base width; CSA = 1.75 m2, volume = 440 m3. (**300 m3). Wall volumes 2 m2 × 250 m × 2 walls = 1000 m3. Amount of fill required = 560 m3. (**3 m2 - 1500 m3).
Other ponds: 0.2 m below grade 250, 2 × 300 m, 3 m base width, CSA = 0.6 m2, volume = 0,6 m2 × (250 + 300 + 300) → 510 m3.
Wall volumes:
0.5 ha ponds: CSA = 2.5 m2, 25 × 250 m × 2 → 1250 m3. (** 3 m2:
1500 m3).
0.2, 0.1 ha ponds: CSA = 2 m2, (300×29) × 4 → 2400 m3 (**3 m2: 3600 m3).
Amount of fill required = 3140 m3.
Secondary drainage:
1 ha ponds: excavate to 1 m below grade, CSA = 3 m2, volume = 75 m3 (** 375 m2).
Others: excavate to 0.5 m below grade, CSA = 1.25 m2, volume = 3 ×
300 × 1.25 = 1125 m3 (** 675 m2).
Walls: 1 ha, 0.5 ha: CSA 2 m2, volume = 2 × 2 × (250 + 300) (** 3
m2: 3300 m3) = 2200 m3.
Walls: 0.2 ha, 0.1 ha: CSA = 2 m2, volume = 2 × 2 × (300 + 300) (** 3 m2: 3600 m3). Fill required = 2725 m3.
Ponds:
1 ha ponds, 3 × (60×165 m), dividing wall sections, CSA = 2 m2, 4 walls of 165 m required → 1320 m3 (** 3 m2: 1980).
0.5 ha ponds, 9 × (40×125 m), dividing walls, CSA = 2.8 m2, 11 walls of 125 m → 3850 m3. (** 3 m2: 4145).
0.2 ha ponds, 18 × (30×65 m), dividing walls, CSA = 2.2 m2, 20 walls of 65 m → 2860 m3 (** 3 m2: 3900).
0.1 ha ponds, 27 × (20×50 m), dividing walls, CSA - 2.2 m2, 29 walls of 65 m → 3190 m3 (** 3 m2: 4350).
Total = 11,220 m3.
Excavation volumes: | 3 × 1 | ha × 0.5 m | → | 15,000 m3; |
9 × 0.5 | ha × 0.2 m | → | 9,000 m3; | |
18 × 0.2 | ha × 0.2 m | → | 7,200 m3; | |
27 × 0.1 | ha × 0.2 m | → | 5,400 m3. |
Fill, river side, 200 m bank length × 20 m × 1 m deep → 4000 m3.
Note: ** volumes required with more generously sized walls, etc. See also Tables in text of main report, summarizing excavation/fill balance.
F Design: pipe sizes, pond wastes
Assume complete pond drainage as in Table D1.
ponds | avrge/hr | peak/hr | ||
1 ha | 10,000 m3 | 5 hrs | 2,000 m3 | 6000 m3 |
0.5 ha | 5,000 m3 | 4 hrs | 1,250 m3 | 3750 m3 |
0.2 ha | 2,000 m3 | 3 hrs | 666 m3 | 2000 m3 |
0.1 ha | 1,000 m3 | 2 hrs | 500 m3 | 1500 m3 |
Assume peak flow conditions at 3 × average; with pond full, drainage channel is approx. 50 % full, thus Dh ± 0.5 meter, with typical pipe length of 3 metres.
Thus Q, 1/sec, = 4.5 × 10-4 × d*2.69 × h*0.56; h = 0.5/3: h*0.56 = 0.366.
The required sizes are shown in Table D2.
ha | Q | d*2.69 | d,mm | 1 pipe | 2 pipes |
1 | 1667 | 10,121,433 | 401,0 | 400 (16") | 300 (12") |
0.5 | 1042 | 6,326,655 | 337.5 | 350 (14") | 240 (10") |
0.2 | 556 | 3,375,835 | 267.2 | 250 (10") | 180 (8") |
0.1 | 417 | 2,531,876 | 240.1 | 250 (10") | 160 (6") |
The design is based round the capacity required, for broodstock, spawning, hatching, and live feed production for a cycled output of 500,000 Penaeus PL. A generous oversizing of facilities provides for other species and for different levels of production. The facilities are designed for good flexibility of use, and can be expanded at a later date.
Quantities are based on nominal area of the station's pond facilities; i.e. approx. 15 ha, assuming the provision of all stock requirements from three larval production cycles. Assuming an initial pond stock density of 3/m2, corresponding to a crop yield of 180 kg/ha at average size of 15 g, stock survival 40 %, this implies a requirement of 450,000 or 150,000 per cycle.
Based on a 40 % survival to PL20 from hatch, this requires 375,000 hatched larvae per cycle, corresponding to production from 1 or 2 females of larger species such as monodon, semisulcatus, stylirostris; up to 20 females of smaller species such as merguinsis. Assume capacity for a minimum 10 pairs of spawners.
Maturation facilities: either one or two of the smaller site ponds, or specially provided tanks; a single 12 m3 tank is sufficient for 50/60 monodon, up to 200/300 indicus. Prior to this, for bringing into condition a similar system can be used, with a lower stock rate, or a pond, e.g. 100–500 m2, 1–2 m deep, ideally with ‘false bottom’, with water exchange 25–30 %/day, stocked at 1–3/m2.
Spawining tanks: typically 100–150 litre size, 1–3 spawners/tank. Thus four tanks would be more than adequate.
Hatching tank: using more intensive methods, an initial stocking density of 100/1 can be considered. Thus a single cycle of 375,000 requires 3.75, say 4 m3 capacity, using, say 0.1 m3, 0.2 m3, 0.5 m3 1 m3, 2 m3 hatchery units, to allow a range of management practices, and good flexibility of use.
Nursery holding: provision may be made in the ponds themselves as an alternative, and as a means of temporary holding and/or conditioning, larger tanks may be used. At a density of 10/litre, with 100 % WE/day a capacity of 200,000 would require 20 m3 tank volume.
Feeding facilities: base on a standard algae/artemia system initially. Thus, typically,
Z - M1: ± 100–1000 × 10*3 cells/ml supplied. Based on 2 m3 capacity; at 10*3/ml, thus requires 2 × 500 × 10*3 × 10*6 cells = 1 × 10*12 cells.
Assuming this is required daily (which overestimates actual usage), and that culture produces 10*6 cells/ml from 10 5/ml inoculum every 2/3 days - say average 4 days -> production is 0.25 × 10*6 cells/ml/day. Culture volume required is l × 10*2/0.25 × 10*6 or 4 × 10*6 ml = 4 m3. Note this the final culturing volume; see later for (smaller) starter culture volumes.
m2 - P5: from 0.1 – 5 g/10,000 of artemia are required daily, or 1.5/ml. Assuming 5/ml, based on 2 m3 capacity at 0.01 mg this is 100 g, this supplies 10 × 10*6 daily. On a numerical basis, for a batch of 375,000, say 300,000 by this stage, 5 g × 300,000/10,000 = up to 150 g daily would be required. In practice this may well be reduced by using other feed. Artemia nauplii can be hatched at densities of up to 10 g/l, say 5g/l in this instance, thus requiring a capacity of 30 1 for a daily hatch. Assuming some overlaps for hatching times, allow 50 litres.
Sub-adult artemia may also be produced as a supplement or weaning feed for larger PL's - fed typically at 5g/10,000 PL, with a stock of 250,000 PL, thus would require 125 g of subadults. Based on a 14-day culture period, this is 1750 g, say 2 kg/14 days. With a typical yield level of 5 kg/m3, this requires 0.4 m3 rearing volume. Initial inoculation is usually 10,000/litre, thus requiring 4 × 10*6 nauplii per rearing volume: ± 300,000 per day. Inoculation weight is 0.1 g/litre for yield of 5 g/l. Daily input average is 3 g cysts.
Using brachionus to feed larval stages, on the basis of typical harvests of 80 % of stock at 100/ml every 5–7 days. Assuming 80/ml/6 days -> 13.3 animals/ml/day. Typical feeding rate is 350/larvae; at a stock of 200,000, this requires 70 × 10*6 animals/day. Thus volume required is ± 5.3 m3.
Typical algal input, if used is 10*6 cells/ml, for a final harvest of 80 rotifers/ml. Thus ratio algae: rotifers is ± 10*4 :1. Thus algal requirement as above is 70 × 10*10, or 0.7 × 10*12/day. With typical production ± 0.25 × 10*6 cells/ml/day (see earlier) this requires ± 3 m3.
Stock and starter culture facilities
Total algal demand, for various purposes is approx. 2 × 10*12 cells/day. This is inoculated into the final culture vessels at ± 1/10 final concentration, from cultures at ± 2 –5 × 10*6 cells/ml after 4/5 days.
Thus volume required: typically in 20 1 carboys is 0.1 × 2 × 10*12/ (2 × 10*6/5) = > 10*5 ml or 500 liter.
For the prior stage, typically small flasks, 200 ml, inoculation is at 1/10 final concentration, which at similar productivity levels -> 50 litres.
For the stock cultures, inoculum is typically 1/20, hence volume required is 2.5 litres. In practice this is increased to provide reserve stocks, and to maintain additional stock lines.
Use of facilities for other requirements.
As specified, the facilities are generously sized, and would permit ample scope for holding of macrobrachium stocks, or fish. To allow for additional stock holding, however, broodstock and hatchery tanks can be increased in number, and accomodated by the existing space and services.
Summary of facilities/volumes: note some tanks are interchangeable. Additional space is allowed for contingencies.
Broodstock: | - ponds 2 × 100 m2, 2 × 50 m2 = total 300 m2; |
- maturation tanks 1 × 20 m3, 2 × 10 m3, 4 × 5 m3 = 70 m3; | |
- spawning tanks 10 × 200 1, 3 × 1 m3 = 5 m3. | |
Hatching: | - 12 × 0.1 m3, 10 × 0.2 m3, 4 × 0.5 m3, 2 × 1 m3, 2 × 2 m3 = total 6 m3 |
Nursery: | - 2 × 1 m3, 2 × 2 m3, 3 × 5 m3 = 21 m3. |
Feeds: | - algae - stock 5 litres; |
- inter 50 litres; | |
- pre-final 500 litres; | |
- final 4 × 2 m3 = 8 m3; | |
- artemia 5 × 10 l, 2 × 200 l = 0.5 m3; | |
- rotifers 5.3 m3, say 4 × 2m3. |
A WATER SUPPLY SPECIFICATIONS
General purpose wash/cleaning fresh water
Total requirements may be estimated as follows:
Residences = 300 × 4.5 litres/head/day | → | 13.5 m3/day; |
Research station = 100 × 1.04 h/day | → | 1.0 m3/day; |
Laboratory use = see table, factor 0.1 | → | 7.5 m3/day; |
Total 22.0 m3/day. |
Assuming a water depth of 60 metres, with discharge point to storage tank above 3 floor residential building ± 15 metres, pump power on 4 hr pumping duty, with 5 m system loss is 5.5 m3/hr × (60+15+5)/273 × p = 2.3 HP (1.7 kW).
Check water supply to other building:
Other 3 floor buildings - requirement 4 m3/day, 6 m3 tank. With supply 4 hrs to fill, 1.5 m3/hr, L = 200 metres, DH = 1 metre.
Q = 4.5 × 10-4 × d*2.69 × h*0.56; Q = 1/sec = 0.42; 0.42 = 4.5 × 10-4 × 0.05 × d*2.69 = 18139; h = 1/200 = 0.005; d = 38 mm, or 1 1/2 " pipe.
With 2 floor buildings, 1 m3/hr, L=300 metres, DH=5 metres: 0.28 = 4.5 × 10–4 × 0.10 d*2.69; d = 25 mm or 1".
Single floor buildings, 1 m3/hr, L=500 metres, DH=5 metres: 0.28 = 4.5 × 10–4 × 0.0987 d*2.69; d = 26 mm or 1".
In other buildings a conventional head tank system and water distribution system with 22 mm, 15 mm copper or plastic piping to sinks, toilets, water heaters, etc. will be used*.
Drinking water supply - provided from (1).
Laboratory water supply - provided from (1).
General purpose field water
See table fin main text for supply requirement = 100 1pm.
On the basis of average 8 hrs use per day -> 48 m3/day avge. On annual basis, 300 days/yr -> 14,400 m3. This could be supplied by storage pond area of ± 7000 m2. The system could also be supplemented with tubewell water, if there is a need to expand capacity.
The system is sized at 80 % usage factor for each laboratory area, at 60 % for total: thus minimum flow required would be 400–500 1pm. Water would be pumped to a main head tank in the services building, volume of 20 m3 in two × 10 m3 tanks, with a minumum 1 m Dh between there and local supply tanks. Pump power required is 3.1 HP (2.4 kW) at 10 m head, for 60 m3/hr.
Analytical laboratory - reservoir tank 2 m3, Dh to usage parts 2 m minimum. Supply to building - fill in 2 hrs - 1 m3/hr, L=200 metres.
Q = 0.28 = 4.5 × 10*4 × 0.052 × d*2.69; d = 33 mm (1 1/4").
Supply to laboratories - maximum flow 100 1pm; L=50 m, Dh=2 m, Q = 1.67 = 4.5 × 10–4 × 0.1649 d = 41 mm (1 3/4 to 2").
A = 2" main can be used, with 1" droppers to main supply points.
Disease/toxicology laboratory - reservoir tank 3 m3, flow 2 m3/hr. Q = 0.56 = 4.5 × 10*-4 × 0.051 d*2.69; d = 42 mm (2"). As with (i) a 2 “main can be used with 1” droppers.
Demonstration laboratory - reservoir tank 3 m3, flow 2 m3/hr; d=42 min (2m). Here a greater short-term flow is required: 300 1pm. Thus Q = 5, d = 6/min (2 3/4 - 3").
3" main can be used, with 1 1/2" droppers to supply points.
Hatching building - reservoir tank 5 m3, but can use similar water supply pipe. Internal supply as per (iii).
General purpose salt water supplies
During regular use in dry period, usage is as per Table 25 (main text) with total at 40 % overall usage rate of 5441 pm, 32.6 m3/hr, which gives sizing for normal use. For individual use in each location, peak usage is 80 % of individual total. As with the field fresh water supply, the supply is drawn up to a reservoir tank at the services unit, from which it is distributed to the other locations. A sizeable part of this supply is in fact used at external field location, and so the main flows through the reservoir tank are at most about 20 m3/hr.
During the wet season, supplies are considerable reduced, and there is the option either of running with low salinity water, or using stored saline water. For this purpose a large reservoir (2 × 150 m3) is provided at the service unit and storage ponds can be filled.
The main reservoir tanks, 2 × 10 m3, are similar to those for
fresh water. Averaging capacity is 60 m3/hr; approx. 3.2 HP
(2.4 kW) at 10 m head.
This system is the most regularly used of the supplies, and
serves most general purpose requirements. There should be two
intake lines. Sizing is:
16.7 1/sec = 4.5 × 10*-4 × d*2.69 × 0.02*0.56. Hence d=112.8 mm
Thus 2 × 4" lines will take water to the initial reservoir/silting tanks, from which they will be pumped via 2" lines to the upper reservoirs.
Supplies to buildings:
Supply to analytical laboratory. A storage tank of 3 m3 is provided; with 1 hour fill; 3 m3/hr. Q = 0.84 = 4.5 × 10*-4 × 0.051 × d*2.69 d= 49.7 mm, 2". A 2 1/2" or 3" line could provide some additional reserve.
Supply to laboratories: minimum flow 150 lpm - 2" line with 1" droppers.
Disease/toxicology laboratory. Reservoir tank 5 m3, filling 3 m3/hr. Requires same pipe as above. Supply inside as (i).
Demonstration laboratory. Two × 3 m3 reservoir tanks, filling 6 m3/hr; Q = 1.68; d=64.3 mm. A 2 3/4" supply line should suffice.
Internal supply maximum flow = 500 lpm; requires 74.5 mm (3") internal main; 4" provides better capacity.
Hatchery laboratory sized as for demonstration laboratory.
Note the above system can be used for intermediate quality salt water by employing one of the service reservoir tanks.
High quality salt water
This supply runs from the main seawater supply and is pressure sand filtered in the services unit, then run to the feeds/larval rearing section of the hatchery. Tanks are provided for additional capacity for longer term expansion.
The water supply is further treated inside the hatchery building for additional quality. Maximum flow rate is ± 100 lpm, with normal requirement ± 20 lpm.
Stored water is percolated through a conventional gravity flow sand filter, and stored in a holding tank (2 m3) from which it is pumped through a pressure filter with 20–40 grade sand, removing particles down to ± 5 um. Pressure required is approx. 10 – 15 m, with a final system pressure of ± 30 m; pump rating is ± 1 HP (0.75 kW) in two units.
Water is supplied via a pressure reducer at this quality, or is run through cartridge filters (Dh = 10–15 m) and if required UV sterilization, before use in the algal culture unit.
Q=1.68 1/sec, Dh=5 m/100 m; h*0.56 = 0.187. Thus d=40 mm, 1 3/4". This pipe must be suitable for the pressures involved.
If the layout prevents the services building from being close enough to the hatchery unit, it may be more convenient to set up the filtration system at the hatchery. It may also be preferable to supply the system with double lines (1") to permit routine disinfection/sterilization turn-by-turn.
Full/variable salinity water
This is provided by mixing (4) and (5) and/or adding sea salts. Small reservoir tanks can be set up in relevant laboratory areas, and mixed water transferred by bucket or by small portable pump (e.g. 1/8 - 1/6 HP: 100 – 150 W) to required locations.
Recycle systems
Several recycle systems layouts are shown in Figure 25 (main text). These are simple, established designs adapted or expanded as needs dictate.
Grouped facilities
If several of the buildings are grouped together, the water distribution system can be sized accordingly.
B DRAINAGE SPECIFICATIONS
General purpose drainage
Conventional 100/150 mm (4/6") drainage grade PVC, with trap access, rodding points.
Laboratory drainage
Normally from flow grids, with interception traps, to 100/150 mm drainage grade PVC.
If layouts prevent the use of a separate system, an alternative (though less ideal) is to run laboratory sink drains into the normal drainage system and run floor drains to the external storm drains, thence to the drainage canal.
C POWER SUPPLIES SPECIFICATIONS
Loads and usage factors accord with conventional practice. approximate loadings for each section are shown in Table F1.
Table F1 - Approximate power loads
Residential buildings | - allow standard per person rates. |
Administrative buildings | - approx. 100 – 150 A (± 20–30kW), depending on airconditioning load. |
Services building | - approx. 150 A (± 30 kW @ 200 V), covers pump and blower requirements, lighting. |
Analytical laboratory | - approx. 200 A (± 40kW @ 200 V) airconditioners, coldstore, small pumps, ovens, instruments, lighting. |
Disease/toxicology/lab | - approx. 100 A (± 20 kW @ 200 V), swell pumps, instruments, lights, airconditioning. |
Demonstration laboratory | - approx. 100 A pumps, instruments, light, icemachine. |
Hatchery laboratory | - approx. 200 A pumps, airconditioner, lights, UV, instruments. |
TOTAL LOAD of research station including external lights, etc.: 900–1000 A (± 200 kW) plus residential use. |
D AIR SUPPLIES SPECIFICATIONS
Air usage is defined in Table 27 (main text). Based on an 80 % usage rate, 140 m3/hr is required. With a working pressure of 1.5 m water and a system loss of 0.5 m, rating is ± 6 HP, 4 kW. Allow 10 HP for additional needs (2 × 5 HP).
HP=0.1318 Q, (m3)/hr × H(m) m.
At the allowed pressure drop, the air flow could easily be carried in 1" (25 mm pipe). If this is acceptable for the blower model concerned, this would conveniently be used to carry main supplies. Otherwise a balancing main of 50 – 75 mm should be used. For most purposes, droppers of standard aquarium tubing will be satisfactory, though for larger tasks - e.g. large broodstock tanks, reservoirs, 10 or 15 mm PVC, ABS pipe or reinforced plastic pressure hose may be used.
E COOLING AND VENTILATION SPECIFICATIONS
Normal airconditioning units would be used for standard work rooms, offices etc.
Algal culture rooms will require at least double the standard room volume requirement, e.g. with 40 – 40 W tubes, assuming 70 % as heat -> 1120 W heat input. Additionally, it is preferable to maintain temperatures at 20–25 'C. On lighting alone, a duty of ± 4000 BTU/ hr is required.
The cold store area should be capable of holding material down to at least -10'C, preferably -20'C. For simplicity a single chamber can be used, with materials placed near the evaporator for freezing, moved around to the sides for storage. As an approximate guide, 30– 40,000 BTU/hr would be required (8.8 – 11.8 kW) for a small store of 2 m × 2 m × 2 m height, with freezing capacity of 50 kg/hr.
Table F2 - Miscellaneous services specifications
Lights: | |
40 W bulbs | - 3000 lux, for test tubes 250 ml flask shelves. |
- 5000 lux @ centre of empty vessels. 2–4 bulbs. | |
Guillard | - 750 – 1000 lux needed (measured horizontally) - 2×30–40 W bulbs for stock cultures, 1500 lux - small flasks. |
- Carboys - 4 × 72" × 40 W bulbs. | |
Seawater: | - algal cultures: 50,10,5,l u filter (cartridges changed, cleaned /2 weeks). |
- drain and dry distribution pipe nightly. Circulate 60 'C tap water weekly. | |
- smaller systems:filter 0.22 u stainless steel Millipore | |
- Note: Galveston subsand, settling. 60 grade filter 10 u 20–40 grade 3–5 u, cartidge filter to 1.0 u. | |
Air: | - 0.2 – 0.3 bar algae 1 u filter 0.2 % CO2. |
- downwards slopes on pipes for water to drain. | |
- 6 mm glass tube into culture vessels. |
The costs of specialized equipment for the construction of BFRS (excluding equipment for research purposes) are summarized in Table 31 (main text). In this Annex G sizing and specifications are provided.
Generators
To cover essential hatchery operations, limited laboratory services, cold store, critical airconditioning needs, aeration, recycle pumps (Priority 1).
Hatchery operations - lights, pumps, autoclave | = 20 kW; |
Laboratory services - lights, equipment | = 10 kW; |
Cold store | = 15 kW; |
Airconditioning | = 10 kW; |
Aerator | = 8 kW; |
Recycle pumps | = 10 kW; |
Total | = 73 kW. |
Assuming a 60 % usage factor, a pair of generators, each rated at (0.73 × 0.6) 44 kW will cover most requirements. Both generators can be run if required. In addition, a small generator of ± 5 kW will be available for external use and supplementary needs.
Blowers
To cover complete system requirements, each rated for 100 % demand. See Table 27 for details of system load - 140 m3/hr at 2 m head.
Pumps
Main water supply pump, for supply to ponds (optimal) each to supply 20 % of system requirements daily at pumping head 2 m (operating head 1 – 4 metres). Direct drive diesel, with angle shaft or gear drive, axial flow 2,800 m3/hr. Delivered power 30 kW, applied power 35 – 40 kW.
Water supply pumps:
Tanks
GRP/polythene; polypropylene only.
General use tanks
Water storage/rearing tanks, 2 as above.
Recycle system tanks
Aquarium tanks, polycarbonate, 48 × 100 litre, rectangular;
24 × 50 litre, rectangular;
20 × 20 litre, circular.
Algal culture vessels
Flagons, 30 × 5 litre (50 to allow breakage).
Mechanical filtration
‘Millipore’ filters: for bacteriological decontamination, filtration to 0.22 u.
UV sterilization
Inline concentric tube sterilizers, with rating for 100 1pm, maximum.
Airconditioners
Conventional room airconditioners designed for continuous operation
Coldroom/freezer unit
Panelling/insulation to be provided locally. Evaporator, compressor, condensation units - latter externally mounted, capable of maintaining -20 ‘C at + 30’ Cambient with storage volume 6 m3, and of air blast freezing up to 50 kg per hour. Note this could also be provided as package kit.
Ice making machine
Capable of handling slightly saline water, producing flake ice at minimum rating 100/kg/day. No hopper required.
Maingate sluices
Proofed steel screw-down sluice gates, with wear-resistant liner, 1 m2 open area.
Aquarium sundries
Air, water valves, small plastic aquarium gang valves, also Eheim or equivalent 8–12 mm valves.
OFFICE OF THE
EXECUTIVE ENGINEER
FRI, MYMENSINGH
Memo No.: | Dated: |
To:
Sub: Invitation for proposal for Consultancy Services for design and supervision of construction of the Brackishwater Fisheries Research Station (BFRS), Paikgacha, under WB Agricultural Research II Project.
Dear Sir,
The Fisheries Research Institute, an agency of the People's Republic of Bangladesh proposes to engage a qualified consulting firm to take up the detailed design and supervision of construction of the Brackishwater Fisheries Research Station (BFRS), as described in the ‘Terms of Reference’. Attention is drawn in particular to the time schedule required for the work.
The background information and the terms of Reference for the Consultancy Services are attached hereto.
If you are interested in undertaking this assignment, you are invited to submit a technical proposal and a financial proposal in two separate envelopes for the services required under the Terms of Reference. The envelope containing the financial proposal must be firmly sealed. Your proposals would eventually form the basis for negotiation and ultimately form a contract between your firm and the Fisheries Research Institute.
Your technical proposal should be prepared in English and should cover in some detail the following matters:
Background, organization and experience of your firm for the purpose of providing the proposed services. A list of past and present works of similar nature undertaken by your firm should also be submitted. Full details of any firms with which you are associated, or with which you would be associated for the purpose of carrying out the Project, should also be provided. If you were ever blacklisted as a Consultant by any Organization, please provide details as to the reason and circumstances.
Proposed technical approach and work plan including:
A bar chart indicating clearly the estimated duration and the probable timing of the assignment of each professional to be used.
Name, age, background, employment records and detailed professional experience of each technical personnel to be assigned for providing the proposed services with particular reference to the kind of experience required for the Project. A copy of bio-data format to be submitted is attached.
Note that failure to dislose any relevant information, or falsification of data may result in immediate disqualification.
Your financial proposal should be prepared on a cost-plus-fee basis and should be accompanied by supporting documents to justify the elements involved. The financial proposal should contain an estimate of the total cost of the services.
The selection of the Consulting firm to be invited for contract negotiation will be based on the quality and suitability of the technical proposal submitted. The selection of consultants shall be made on the basis of evaluation to be performed by the Tender Committee of FRI according to the format attached.
The firm selected on the basis of its technical proposal will be invited to negotiate financial and other terms of the contract without delay. Should the negotiation prove unsatisfactory, the firm submitting the next ranked proposal will be invited for negotiation (and so on if necessary until an agreement is reached with respective firm).
It is anticipated that the contract negotiations would commence around and the assigment would start around
The contract will be awarded on an exclusive basis; nontheless, the client reserves the right to eliminate any components of the work here described.
You are requested to ackowledge the receipt of this letter and to indicate whether or not you intend to submit the proposal.
Your detailed technical proposal should be submitted in 10 copies and your financial proposal also in 10 copies (in wax sealed envelope) to reach the following address not later than :
Executive engineer,
Fisheries Research Institute,
Mymensingh.
Visit to the Project Area. In order to familiarize yourselves with the Project area and to assess the extent of services to be provided by your firm, you are advised to visit the Project area. However, any cost incurred by you for such a visit will not be reimbursed.
In the event that you desire additional information, we would endeavour to provide such information expeditiously, but any delay in providing you with such additional information will not be considered as a reason for extending the submission date of your proposal.
Yours sincerely,
TERMS OF REFERENCE FOR CONSULTANTS
DESIGN AND SUPERVISION OF CONSTRUCTION
OF BRACKISH WATER FISHERIES RESEARCH STATION, PAIKGACHA
Consulting firms will be engaged to assist with the project implementation. The role of the consultant will be divided into two areas 1) and 2), which will be expected to overlap during the commission of the project (see attached time schedule).
1) Preparation of detailed design of the proposed BFRS, Paikgacha, based on the outline design and specifications of the Aquaculture Engineering Consultant, including:
The consultants will be expected to provide the following:
2) Supervision of construction
Upon award of the contracts and execution of agreements with the contractors, the consultants will, in conjunction with the Client, establish with the contractors the procedures necessary for implementing the Project in timely and economic manners in line with the Plan and Operations of the Project. The consultant will:
The consultants will also establish construction monitoring under which their responsibilities will be:
3) Co-ordination of work
As shown in the project schedule, it is anticipated that the contracting work be let in a number of phases, to allow timely completion of the Project. The consultants will be required to plan and co-ordinate their work to enable this phasing to be carried out effectively.
MAJOR WORK DURING LAST TEN YEARS WHICH BEST ILLUSTRATES QUALIFICATIONS
The following information should be provided for each reference project in the format indicated below
Project Name: | Name of client: |
Project location: | |
District: | |
No of sites: |
Professional staff provided | Cost of project TK: | |
No of staff: | No of mm: |
Start date | Completion date | Approx. value of services TK: |
month/year: | month/year: |
Name of associated firm, if any: | No of man-months of professional staff provided by associated firm: | |
Senior staff involved and functions performed: | ||
Detailed narrative description of project & services provided: |
Firms' name:
BIODATA FORMAT TO BE SUBMITTED WITH PROPOSAL
1. | Proposed position | : | |
2. | Name | : | |
3. | Date of birth | : | |
4. | Nationality | : | |
5. | Education | : | |
6. | Other training | : | |
7. | Language & degree of proficiency | : | |
8. | Membership of professional societies | : | |
9. | Employment record | : | (Starting with present position. List in reversed order of every employment held) |
From | To | ||
Employer | : | ||
Position held and description of duties | : | ||
10. | Detailed tasks assigned in this project | : | Work undertaken which best illustrates capability to handle the tasks assigned |
: | |||
: | (List project name, location, year, position held, i.e. Teamleader, Hydrologist, Agricultural economist, etc., exact duties rendered and time spent on each project) | ||
: | |||
: | |||
: | |||
: | |||
: | |||
: | |||
: | |||
: | |||
: | |||
: |
OUTLINE IMPLEMENTATION TIMETABLE
See Table 29 of the main report text.
SCHEDULE OF WORKS
The scope of consultants work will be as follows (Consultants are invited to indicate their fees):
No | Items | Unit | Fees |
1. | Topographical survey of the site (0.25 m contours) with all physical features & preparation of an exact survey plan of the entire site showing all structures and features at 1:500 scale. | Per 1000 m2 | |
2. | Preparation of Master Plan at 1:500 scale showing the location of the existing features and the proposed new structures including all utilities and services and preparation of land scape plans and site development plan. | Per 1000 m2 | |
3. | Sub-soil investigation at site of the proposed BFRS facilities, guest house, staff quarters and the overhead water tank to determine the physical properties of soil and the sub-soil stratification upto a depth of 20 m including necessary laboratory testing. | Per bore | |
4. | Investigation and test borings to locate a water bearing strata upto a depth of 300 m for a continuous source of adequate quality of drinking water (50 m3 of water per day). a) per m upto 150 m b) per m above 150 m | per m per m | |
5. | Preparation of plans, design, estimate and tender documents for the necessary earthworks, and construction of supply and drainage sluicegates required for the development of the BFRS pond complex Estimates will be based on actual computed amounts of materials required. | % of approved estimated cost % of approved estimated cost | |
6. | Design of the BFRS laboratory buildings (to include architectural design and drawings, structural design and drawings, electrical design and drawings and sanitary water supply design and drawings). | ||
Contract to be divided into 2 phases: | |||
Phase 1: Hatchery laboratory (400 m2) | |||
Analytical laboratory (300 m2) | |||
Services building (300 m2) | |||
Total area: 1000 m¾ | |||
Phase 2: Toxicology/pathol. lab (300 m2) | |||
Demonstration lab. (300 m2) | |||
Total area: 600 m2 | |||
Fee to be indicated by building or per phase. | |||
a) Preliminary architectural drawings; | % of approved estimated cost | ||
b) Detailed architectural design and drawings; | " | ||
c) Detailed structural design and drawings; | " | ||
d) Detailed sanitary and water supply design and drawings; | " | ||
e) Detailed design of specialist water supplies, air supplies and associated reservoirs, distribution systems for laboratory uses; | " | ||
f) Detailed electrical design and drawings; | " | ||
g) Detailed estimate, bill of quantities, specifications and tender document. | " | ||
7. | Design of guest house building (to include architectural design, drawings, structural design and drawings, electrical design and drawings and sanitary and water supply designs and drawings). 1 No (Total area = 300 m2). | ||
a) Preliminary architectural drawing; | % of approved estimated cost | ||
b) Detailed architectural drawings; | " | ||
c) Detailed structural design and drawings; | " | ||
d) Detailes sanitary & water supply design and drawings; | " | ||
e) Detailed electrical design and drawings; | " | ||
f) Detailed estimate, bill of quantities, specifications and tender document. | " | ||
8. | Design of quarters for BFRS staff (to include architectural design and drawings, structural design and drawings, electrical design and drawings and sanitary and water supply design and drawings. | ||
It is intended to divide the construction contract into 3 phases: | |||
Phase 1: 2 type B units at 150 m2 each | |||
2 " C " " 125 " " | |||
4 " D " " 100 " " | |||
2 " E " " 80 " " | |||
Phase 2: 4 type F units at 60 m2 each | |||
2 " G " " 150 " " | |||
2 " C " " 125 " " | |||
Phase 3: 4 type D " " 100 m2 each | |||
2 " E " " 80 " " | |||
4 " F " " 60 " " | |||
2 " G " " 50 " " | |||
All sizes exclude staircases. Fee to be indicated as percentage of estimated cast for each type of unit, with repetition fee as appropriate. | |||
a) Preliminary architectural drawings; | % of approved estimated cost | ||
b) Detailed architectural drawings; | " | ||
c) Detailed structural design and drawings; | " | ||
d) Detailed sanitary and water supply design and drawings; | " | ||
e) Detailed electrical design and drawings; | " | ||
f) Detailed estimate, bill of quantities, specifications and tender documents; | " | ||
g) For repeation of each building; | " | ||
9. | Design of tube-well on the basis of test boring including necessary test pumping to determine the capacity and designing of the external water distrubution system including construction of pump house; determination of pump and preparation of estimate bill of quantities, specification and tender document, etc. | % of approved estimated cost | |
10. | Planning and designing of small waste treatment plant (septic tank) with optional chlorination with capacity of 20 m3/day, and preparation of estimate, bill of quantities, specification, and tender documents, etc. | % of approved estimated cost | |
11. | Preparation of estimate, bill of quantities, specification and tender documents for the provision of site clearance and landscaping. | % of approved estimated cost | |
12. | Constant supervision by providing necessary full time technical personnel as per requirement. | % of actual construction cost | |
13. | Detailed architectural and structural design of the elevated tank with a capacity of 20 m3 and preparation of estimate, bill of quantities, specification and tender documents, etc. | % of approved estimated cost | |
14. | Planning and designing of small water treatment plant of 20 m3 per day including preparation of detailed design, drawing and preparation of estimate, bill of quantities, specification, tender documents etc. | % of approved estimated cost | |
15. | Preparation of estimate, bill of quantities, specification and tender documents for the provision of brick surfaced road along site border, approximate lenght 1000 m, nominal 2 m width. | % of approved estimated cost |
A. GENERAL
The civil works to be proposed for the Project will include:
These works can also be classified depending on their required materials into the following:
Embankments
grass for turfing of embankment surface.
Erosion checking
single 8 SWG wire.
Drainage and irrigation structures
water.
B. CONSTRUCTION MATERIALS
Major construction materials are described below on where and how the materials are obtained.
Earth
Earth to be filled for breaches or resectioning of the embankments can be obtained from outer bounds of the embankments. These outer bounds are not needed to be acquired for construction purpose, because the bounds are owned by the Government. Experience has been shown that earth obtained from the bounds is suitable as earth-fill material for rehabilitation or construction of embankments. Earth materials for back-filling of drainage and irrigation structures will be obtained from the existing embankment where the structures will be placed by cutting or excavating this embankment. The excavated materials will be used for back-filling.
For construction of retardation embankment, land acquisition will be required, because the use of outer bounds as borrow pit would not be viable due to its long haulage. The land acquired will be used for site of the embankment and also used as borrow area. As the retardation embankment will be located near the existing embankment, the soil would be very similar to that of outer bounds and thereby suitable for embankment.
Grass
For the slope protection of embankments from erosion caused by rainfall or high tide, turfing is necessary. Grass for this turfing should be chosen as species which have been known effective. It was found that grass would be easily available from the project area.
Bamboo, timber, and wooden plank
Bamboo is required to make the porcupine for erosion checking work, and timber is used for hydraulic structures, cut-off wall and erosion checking work. The wooden plank is for shuttering and fallboard of drainage sluices. These materials are found to be very obtainable near the project area.
Aggregate for concrete
Sand could be available from or near the project area, but the use of Sylhet sand would be desirable, to be combined with the sand in site in order to get appropriate gradation.
Coarse aggregate is also available but in high cost. Crushed brick would therefore be considered instead of coarse aggregate under the appropriate quality control.
Bricks
Bricks are commonly used for protection works and easily obtained in the region, but the quality is variable. Due to this unreliable quality, the bricks should be used for particular portions through special production by order.
Steel
Mild steel plain reinforcing bars for concrete are being produced in Bangladesh, but for structures requiring large sized bars it is desirable that deformed bars would be used in view of high tensile stress and easy handling. Steel sheet piles, which will be used for cut-off walls underneath structures, should be at the international standard to meet the construction requirements. Flap gates or slide gates can be manufactured in the region, but its selection should be made with care of corrosion by saline water.
Water
Fresh water to be required for concrete would be available in the wet season. However, during the dry season, when construction works are usually mounted up, water availability would be uncertain. For this purpose, some facilities such as a water pond would be prepared for large structures. Fresh water will be stored in this pond in the rainy season and used after floating materials are deposited on the bed.
(Source: WDB)