Buri Water Reticulation

Transcription

1 Buri Water Reticulation Buri village is a large village on Ranongga Island with a population over 400, living in over 60 houses. In the past, some small dams and standpipes were installed. Recently two water projects have been undertaken. The Tavaneka South Community water tank project (four water tanks) was funded under the Australian High Commission Direct Aid Program (DAP). A second project, funded by the Japanese Embassy consisted of a partly built dam, trunk pipeline and one standpipe. Several other standpipes were not installed. Some of the material required for completion remains on site. A study by the Solomon Islands Government (Rural Water Supply and Sanitation) was undertaken in December 2011, and is available to Partner Housing. This project is the substantial completion of the reticulation phase of the previous scheme, with reference to the recommendations of the RSS Report.

2 Buri Water Reticulation - Introduction Purpose The purpose is to provide a secure water supply to Buri village for both drinking and washing. Water Sources Existing small dams, spring boxes and stand pipes (System A) located near the playing fields used for drinking water and washing water. A small dam, Dam (B), provides water via a single DN90 / DN63 PE80 pipeline to a single standpipe. Available flow is in the range 0.15 to 0.30 l/s. A further potable water source, the Source (C), has been identified, but has not yet been exploited. Available flow is in the range 0.08 to 0.13 l/s. Four 3,000 litre public polyethylene tanks and several private tanks collecting roof water. The area has an average annual rainfall of 2,592 mm with a recorded minimum of 2,076 mm. The minimum monthly rainfall is 96 mm. Study The following study forms the basis of this project. Solomon Islands Government (Rural Water Supply and Sanitation) Buri Water Supply Design Report, by Jaidev Vasudevan, December 2011 Spring Boxes Dam B Four Tanks Source C

3 Buri Water Reticulation - Strategy Primary Strategy 1. Connect the existing DN 63 PE80 pipeline from Dam B to the four new header tanks located at the Church via a new DN32 PN9 PE pipeline. 2. Construct six remote standpipes with concrete bases, to provide washing water at various locations throughout the village. 3. Connect six standpipes to the two header tanks via approximately 2 km of new DN32 PN9 PE pipes. 4. Install two new 3,000 litre water tanks and feed rain water from the roof of the Guest House and from the Church. Approximate ground levels are RL 30.0 and RL Future Strategy Further work to improve the water system includes the following. 1. North Ranongga Community Association should implement a water infrastructure management and maintenance program, to ensure the long-term viability of the system. This includes the following. 2. Clean and stabilise the banks of Dam B, and consider installing a filter system. 3. Clean and cover the existing spring boxes and drinking water sources. 4. Install a Ram Pump and rising main to pump drinking water to existing tanks. 5. Install two new 3,000 litre dam water header tanks on a concrete base. Approximate ground level is RL 37.0 and connect to the system and to a supplementary source.

4 Buri Water Reticulation

5 Buri Water Reticulation Locations of Tanks and Standpipes Six standpipes, marked SP1 to SP6 are fed with dam water from Tanks 1, 2, 3 and 4 at the Church. Tank 5(at the Church) and Tank 6 (at the Guest House) provide rainwater collected from roof gutters kilometres Community Hall SP 4 School SP 5 SP 1 SP 2 SP 3 Church Tanks Guest House Tank SP 6

6 Buri Water Reticulation Church Tank Arrangement Dam water flows continually into Tanks 1, 2, 3 and 4 (connected at the bottom). The valves feeding standpipes 1-2, 3, 4 and 5-6 are kept closed at night (allowing the tanks to recharge), and open during the day to feed the six connected standpipes. Tank 1 Dam Water Tank 2 Dam Water Tank 3 Dam Water Tank 4 Dam Water DN40>DN32 reducer 1-DN32 gate valves 1- DN32 PN9 PE redline pipe 1-DN40>DN32 reducer 1-DN32 gate valves 1- DN32 PN9 PE redline pipe 1-DN40>DN32 reducer 1-DN32 gate valves 1- DN32 PN9 PE redline pipe 1-DN40>DN32 reducer 1-DN32 gate valves 1- DN32 PN9 PE redline pipe DN32 PN9 redline pipe 1-DN63>DN32 reducer assembly Existing DN63 PE80 blueline pipe terminating near guest house DN32 PN9 PE redline pipe Valves open during day, locked closed at night

7 Buri Water Reticulation Guest House Tank Arrangement Rainwater from the guest house roof is collected and discharged into Tanks 5 and 6 (connected at the bottom). Drinking water may be drawn off from either tank as required. DN 80 PVC RWDP 1-DN80 x 45 o F-F elbow PVC roof gutter, brackets, joiners and 2 stop ends Tank 5 Rain Water 1-DN40>DN32 reducer 1-DN32 gate valves 1- DN32 PN9 PE redline pipe Valve normally closed

8 1 Plumbing for Standpipes DN15 elbow DN15 plastic pipe DN15 galv pipe, screwed each end 2 - DN15 globe valves DN15 galv tee, F M M 1 DN80 PVC Pipe 1- DN80 PVC elbow Filled with concrete after plumbing has been installed DN15 galv pipe, screwed each end Compacted soil to slope away from slab 50 mm over 500 mm on all sides Thoroughly compact soil below the slab Concrete support DN15 galv elbow DN15 galv M-M nipple DN32>DN15 reducer DN 32 PE joiner 75 concrete slab, constructed after plumbing is positioned 75 concrete slab, constructed after plumbing is positioned

9 concrete slab Concrete Standpipe Pads 500 Compacted soil to slope away from slab 50 mm over 500 mm on all sides.... Finished level of slab as located on site 800 Thoroughly compact soil below the slab 1 x 1 x 75 thick concrete slab, reinforced with SL62 mesh with x edge thickening 1 Top surface of slab should be rebated 800 to channel water towards a drain Concrete Standpipe Pads Number of pads 1 Description Q'ty Unit Concrete 0.2 m 3 40 kg bags of cement 2 bags Sand 0.1 m 3 20 mm aggregate 0.2 m 3 SL62 reinforcement 1.4 m x 50 HW formwork 5.6 m Formwork may be reused on several pads.

10 Fall 75 slab Double Light Duty Tank Pad For a quadruple light duty tank pad (for four tanks), use twice the quantities. Two 3000 litre tanks 1800 diameter Standpipes to be located remote from the tanks and slab Compact soil below slab slope away from slab 50 mm over 500 mm all sides 500 Double Light Duty Tank Pads Number of pads 1 Description Q'ty Unit Concrete 1.2 m 3 40 kg bags of cement 11 bags Sand 0.7 m 3 20 mm aggregate 1.3 m 3 SL62 reinforcement 7.0 m 3 N10 reinforcement 13 m 100 x 50 HW formwork 8.4 m 100 x 50 HW formwork 4.0 m Formwork may be reused on several pads. Finished level of slab at specified level. Tolerance +,- 50 mm 4000 x 0 x 75 thick concrete slab, reinforced with SL62 mesh x concrete beams around edge and across centre of pad. N10 bars top and bottom

11 Height 1.0 m Height 0.8 m 20 MPa Concrete Specification Approximate mix (by volume) 1 : 2 : 4 Cement 8 40 kg bags For 1 cubic metre of 20 MPa concrete, the mix should be: 8 bags (40 kg each) of GP or GB portland cement OR 16 bags (20 kg each) 0.5 m 3 of sand - Sand should be clean sharp sand, NOT brickies sand or plasters sand. Diameter 1.6 m Sand Volume 0.5 m 3 Diameter 2.0 m 1.0 m 3 of 20 mm coarse aggregate - Aggregate should be clean 20 mm river gravel, crushed aggregate or similar. Coarse Aggregate Volume 1.0 m litres of water Approximately litre buckets (300 mm diameter x 290 mm deep). Less water should be used if sand or aggregate are damp. Water litre buckets Basis of calculation: Density of cement, dry sand and dry aggregate 1,500 kg/m 3 Includes approximately 5% allowance for wastage. Source: Cement Concrete & Aggregates Australia

12 Buri Water Reticulation Water Supply from Dam Water Supply from Rural Dams to Community Standpipes This worksheet can be used to check the sizing of small dams, holding tanks and water reticulation systems. Water Demand Number people serviced by community standpipes Water demand from community standpipes Total water demand from community standpipes Water Supply Available Water supply from existing dams Water supply from existing dams Does the water supply exceed water demand 196 people 80 l/person/day 15,680 l/day 0.20 l/sec 17,280 l/day Does the water supply exceed water demand 1.10 Retention Tank Number of hours of use Volume consumed during hours of use Volume delivered during hours of use Required volume OK 10 hours/day 15,680 litres 7, litres 8,480 litres Required volume 8.48 m 3 Number of tanks 3 Nominal volume of each tank 3,000 litres Calculated total capacity 9.02 m 3 Is the volume sufficient? Overcapacity 1.06 OK