Government plans to reuse 600,000 cubic meters of rainwater a year from Kappara reservoir
A 10,000 m3 capacity reservoir is currently being constructed at the end of Wied Ghollieqa (Kappara) to act as a temporary retention basin for storm water coming down from the same valley. and presently flooding the area of Triq Turu Rizzo, Triq Edgar Bernard, Triq Sliema down to The Strand.
It is estimated that 600,000 m3 of rainwater will be pumped from the reservoir annually, which will be made available for landscaping and agriculture.
Although the government has abandoned grandiose plans to harvest rainwater through a €438 million project set to recover 5.5 million cubic meters of water, it still plans to recover 680,000 cubic meters of rainwater from its flood relief project while focusing its efforts on treating the daily supply of 230 million cubic meters of sewage from Malta’s three sewage treatment plants.
The reservoirs project will be form an integral part of the Flood Relief Project that is being proposed to alleviate floods in the B’Kara – Msida – Gzira water catchment area.
The Ministry for is also exploring the possibility of making use of the rainwater that can be gathered through a tunnel system that will be gathering the rainwater.
Since rainwater that this system will be gathering is mostly gathered from the streets of highly urbanised areas the possibility of having this rainwater runoff highly polluted with sewage and other pollutants is very high.
For this purpose the Government is therefore incorporating in this project a pilot project to monitor the quality of such runoff in order to determine the actual treatment that would be needed for its re-use.
The inlet chamber of this reservoir will be provided with grit and oil silting chambers and the floor of this reservoir will be constructed in a manner to allow the gathered storm water filter into the underlying soil/rock strata.
The reservoir will also have an overflow that will be connected to a tunnel system that will discharge water directly from the Ta’ Xbiex spillway outlet into Marsamxett Bay in case the rainfall is so heavy that the reservoir will not cope to hold it. This will provide the necessary storm relief to the areas mentioned above.
A pipe connection will also be made with the Ta’ Xbiex sea outlet so that rainwater that is gathered at this outlet can be pumped to the reservoir when this is empty. It is estimated that from the Ta’ Xbiex spillway outlet it will be possible to pump around 600,000 m3 of rainwater annually.
The reservoir will occupy a superficial area of around 2080 sq.m. and its roof will be landscaped by providing a layer of soil and planting to make it blend into the existing landscape.
Automatic water sampling equipment will be installed in this reservoir and also at the Ta’ Xbiex sea outlet to monitor the water quality. The water samples will be analysed for at least one hydrological year in order to determine the treatment that will be required to do to this water in order to make it good for use to irrigate landscaped areas or agricultural fields.
The government’s decision to slam the 438 million project was slammed by consultants conducting a strategic environment impact assessment on the Storm Water Master Plan because it lacked any infrastructure for water re-use to alleviate pressure on ground water extraction.
But a Ministry spokesperson told MaltaToday that the SEA was conducted on plans which included little or no re-use of rainwater.
The government has now presented new proposals which include an element on re-use.
The spokesperson also explained that the storm water project must also be seen in the light of the government’s decision to focus on the treatment of sewage water from Malta’s 3 sewage treatment plants, two of which are already operational but are still disposing the sewage in to the sea.