Jersey Water is preparing to bring Val De La Mare reservoir back in to service after five months following the discovery in February of pesticide Oxadixyl in streams feeding the reservoir. 

To enable the water from Val De La Mare to be used over the summer, the company has applied for a temporary dispensation under the Water (Jersey) Law 1972 allowing it to exceed the strict regulatory limits.

Val De La Mare is the water company’s second largest reservoir in terms of capacity of 938.7  megalitres and at 192.9 metres in length, 32.81  metres in height and 24.31 metres in depth, by far the largest in terms of size.

Helier Smith, Jersey Water’s Chief Executive, said:

“The need for a dispensation in this instance is principally a regulatory compliance matter under the law rather than a health-based issue. The water that we supply will remain safe to drink. The presence of Oxadixyl in Val de La Mare Reservoir and elsewhere is historic and has arisen due to factors outside of the company’s control.  We are working hard to find a way to remove Oxadixyl through treatment but in the meantime will work to complying with the lower limit where it is practical for us to do so.”

Company has applied to increase limit on precautionary basis for a period of 3 years

The regulatory limit for oxadixyl in treated water is 0.1 Micrograms per litre (ug/l) which is equivalent to one part in 10 billion. The company has applied to increase that limit on a precautionary basis to 0.3ug/l, which is 100 times lower than the health base limit of 30ug/l, for a period of 3 years whilst it researches and implements a long term treatment solution to the oxadixyl problem.

The application for dispensation is currently being considered by the Minister for the Environment in consultation with the Minister for Health & Social Services.

Val De La Mare Reservoir represents 35% of the Company’s water storage capacity.  The Company is bringing the reservoir back into service during the summer which will also allow Queen’s Valley and Grands Vaux (which have been in use since February) time to refill.

Jersey Water will continue to manage water quality by blending and treatment but the company warned that use of water from Val De La Mare increases the risk that on occasion, levels of oxadixyl in the treated water supply may exceed the regulatory limit, but remain safe for consumers.

Helier Smith said:

“Val De La Mare Reservoir is a significant source of water for the Island which we need to bring into service in order to manage our water resources. Given that oxadixyl was only discovered in February, there is uncertainty over the likely concentrations of oxadixyl over the remainder of the year. Current indications are that concentrations in Val de La Mare are likely to increase over the summer. In these circumstances, normal blending options may be insufficient to enable us to comply with the 0.1ug/l limit all of the time.”

 “We have therefore taken the precautionary steps of applying for a dispensation to cover this eventuality. We will work with the Minister for Environment as he continues to discuss pesticide use with the farming community, in order to protect the Island’s water sources from further contamination. Our laboratories have stepped up its testing programmes to monitor water sources supplying our reservoirs and will continue to report any environmental breaches.”