DEMONSTRATION ACTIVITIES - Xai-Xai IDP
7.1.5 Infrastructure Preliminary Projects Water Supply
There is no existing water supply to Praia Velha. The nearest existing pipelines are to the east in the existing town of Xai-Xai Beach but are old pipes of small diameter and uncertain condition designed to supply only the few existing houses. The pipes are connected to the small existing low level reservoir and are, therefore, subject to low working pressure and do not have capacity to supply Praia Velha.
The proposal is that the whole coast will be supplied from new high level reservoirs with a top water level of 88 metres which allows for development of stands to the 60 metre contour as a general rule. All new pipe work should be designed accordingly to a working head of 90 metres
pipes should, therefore, be Class 9 in the PVC range of equivalent.
A new pipeline must, therefore, be laid to Praia Velha with Class 9 pipe. Initially, this pipe can be connected to the low level reservoir to supply water for the early development of the area. Provided the low level reservoir has water in it this elevation should be sufficient to supply the highest stands which reach the 45 metre level. It must be emphasised, however, that the reservoir is often empty, sometimes for a few days at a time so the supply at present is intermittent.
In due course Praia Velha can be connected to the new reservoir at higher pressure. Ideally, the pipes should be sized to supply the whole of the township of 120 stands but development can be phased to suit funding availability and projected growth rates for building of homes, although this will be more costly in the long run.
Proposed sizes and lengths of mains are given in Table 20 below:
Reservoir to east border of township
Minor reticulation and interconnection
To Praia Velha
In Praia Velha
Praia Velha Water Supply and Reticulation
The cost of the water supply system can be easily ascertained by applying current construction costs to the pipelines scheduled above and allowing for the cost of connections and water meters to each property. Policy will dictate as to whether an additional contribution is required from purchasers of stands towards the costs of the proposed new bulk water supply system with new pumps, pumping mains, reservoirs and chlorinating, and supply mains
Liquid Waste Treatment and Disposal
Initially, all liquid waste for the houses at Praia Velha will be disposed of by septic tanks with soakaways. Because of the steep terrain care must be taken in siting soakaways sufficiently within each property to ensure that there is no surface seepage onto lower neighbouring
properties or the road. sewerage reticulation with of the property.
All septic minimum
tanks should also be disruption in future and
located this will
to connect to the future usually be on the low side