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As well as collecting water in the Island’s main reservoirs, the Company also collects water from many of the Island’s streams which are remote from the reservoir catchment areas. These streams are fed by rain water running off the land and by underground springs.

The water in the streams is caught in a collecting pond or small reservoir. Each collecting pond or small reservoir has its own pumping station allowing the water to be pumped into one of the main reservoirs for storage before treatment.

The Company operates 8 raw water stream abstraction points around the island. These are located at:

• Fern Valley
• Grève de Lecq
• La Hague
• Le Mourier
• Pont Marquet
• St Catherine
• Tesson
• Vallée des Vaux

The amount of useable water that can be collected from each stream varies according to the size of the catchment area, the levels of rainfall and the quality of the water in the stream.

Stream flows are generally at their highest in the autumn and winter and can reduce significantly or even dry up completely in the summer (depending on the levels of rainfall).

In order to ensure the year round availability of water from the Le Mourier stream, which has high flow levels but variable water quality, the Company has installed an ultra-filtration and reverse osmosis plant within the pumping station. Untreated water can pass through the pre-treatment process at the abstraction point before being pumped to the storage reservoir.