Protecting our Marine Environment - Environmental Protection - Appendix 9 Groundwater Leaflet - Subm

ENVIRONMENTAL PROTECTION, ENVIRONMENT DIVISION, Groundwater in Jersey What is groundwater ND ENVIRONMENT DEPARTMENT

All of the fresh water in Jersey comes from rainfall and why is it important?

falling on to the land.

Rainfall is generally seasonal in Jersey - most of the groundwater

Water is continually moving through the environment –

rain falls between October and March. The this is called the water cycle. Water evaporates from

groundwater store is mainly replenished during the the oceans, condenses into clouds and then falls on the i

period from November to March. During the

land surface as rain. The water then flows into riv

summer groundwater levels fall and this causes some

and back into the sea. Some of the rainfa

streams to dry up.

into the soil and what isn't taken up by pl

Jersey streams are highly dependant on groundwater evaporated, percolates downwards into th

inputs. One study estimated that approximately 67%

This water is known as groundwater. Groun

of the total stream flow comes from groundwater,

continues to flow through the rock, usually at

whilst 33% reaches the stream by more rapid surface

slower rate than surface flows – it can be resi

or near surface routes.

underground for tens of years to thousands of year

The volume of groundwater abstracted in Jersey each

Groundwater provides the water that supplies b

year is estimated to be 3.6 million cubic metres

or well abstraction and it also provides baseflow

(3 600 000 000 litres).

streams and rivers (it seeps out through the

Jersey Water supply over 90% of the Island's banks of the stream or river to add to sur

population with drinking water and the Company

supplied 7.291 million cubic metres (7 291 000 000 Groundwater is very important as a resou

litres) of treated water in 2005. Approximately 97% the Earth's water is saline, which means th

of this water is obtained from surface water sources freshwater. Of this freshwater, approxima

(streams), but as mentioned above over two thirds of bound up as icecaps and glaciers, less tha

this stream flow is derived from groundwater. freshwater is accounted for by surface w

The other 10% of the Island's population are rivers, lak

dependant on groundwater from boreholes and wells groundwa

for their drinking water.

Groun

Remember Effects are long term! Causing or knowingly permitting pollution of Remediation can be difficult and expensive! controlled waters is an offence under the Water Prevention is better than cure! Pollution (Jersey) Law 2000. There are however

strong defences that may be available to persons acting in a responsible manner. A copy of the law Water

can be obtained from the States Greffe bookshop or it can be viewed at www.jerseylegalinfo.je Pollution

Hotline

Once polluted, groundwater can be very expensive or impossible to clean up. Tel: 709535

Water Pollution Hotline Tel: 709535

Groundwater Quality in Jersey Types of Pollution Pollution Incidents

Environmental Protection at the Environment Between 2000 and 2005 approximately 136 pollution Division of the Planning and Environment Point Source -  arises from a specific location that can incidents a year were reported to Environmental

be pinpointed.

Department has responsibility for protecting and Protection.

enhancing the quality of the Island's aquatic Diffuse Pollution -

arises from dispersed or

environment. Environmental Protection carries out

a comprehensive water quality monitoring widespread sources and is difficult to locate. Types of Pollution

programme which includes twice yearly sampling of

approximately 50 boreholes and wells. Oil

Historically high nitrate levels have been detected in Pollution Travels The most common type of pollution incident is oil related. the Island's groundwater. However, monitoring of Bodies of water that Spills from domestic tanks can directly affect groundwater

the Island's groundwater quality over the last 16 appear unconnected quality and render nearby water sources unfit for human years has shown a steady decline in the level of can be interlinked by consumption.

nitrate found. In May 2006 48% of sampled groundwater. For

groundwater was found to be above the European example, pollution Sewage

Union (EU) maximum admissible concentration from a buried oil

Approximately 1 in 10 of the (MAC) for nitrate in drinking water of 50 mg/l drum, leaking into the

Island's households are reliant on (NO3), compared to 61 % in May 1990. soil can be carried by

private sewage disposal facilities. groundwater flow into

Pesticides and their breakdown products have been

a pond and then by a If the effluent quality is poor,

found in some of the boreholes tested. However,

stream to the sea. generally due to a lack of

breaches of EC maximum admissible concentrations

maintenance of the system, this will are uncommon.

affect the groundwater. This may Many groundwater samples show evidence of ultimately affect the drinking water bacteriological contamination. supplies and may cause a direct The groundwater resource of Jersey is particularly hazard to human health.

vulnerable to pollution because the groundwater is Maintenance is vital to reduce the at shallow depth in fractured rock, protected risk of pollution.

only by thin and permeable soils. Groundwater can

be polluted by both point and diffuse sources. Agriculture

Approximately half of the total

Island area is covered by farm land. Frequently Asked Questions Pollution from chemicals, used to

enhance crop yields and prevent Is Jersey groundwater water hard

pests and diseases, can occur if not or soft? The majority of

used carefully.

groundwater in Jersey is

soft to moderately soft. The use of chemicals has been Why did my hair turn green ut it could take tens of after I washed it in borehole water? e contaminants (e.g.

Groundwater in Jersey is usually slightly ready in the groundwater acidic and this can mobilise some trace hrough.

found in groundwater and corrode pipework.

lease remember that although Copper from pipe-work is responsible for the Seawaterintrusion

undwater is out of sight, it green tinge that highlighted and blonde hair can caused byover pumping Water film

from boreholes around grain rtainly should be out of mind. acquire if washed in acidic water. This can be

remedied by treating the water. It is a precious Island resource

that needs to be protected.