Water
Water consumption remains high whilst quality of Hertfordshire’s rivers improves
With groundwater levels falling to below average and little change in domestic consumption levels, recent years have shown that we must all make a contribution towards the more efficient use of water. This is essential in order to cope with Hertfordshire’s expected growth in population and the effects that climate change is increasingly having on our water sources.
Indicator WR1 - Water consumption
Veolia Water Three Valleys (VWTV) domestic customers without meters maintained last year’s water usage at an average of 175 litres per person per day in 2009. Water usage by customers with meters fell back to 2007 levels from 153 litres in 2008 to 142 litres per person per day in 2009.
Water consumption - Hertfordshire Domestic Water Consumption
Source: Veolia Water Three Valleys November 2009 central.veoliawater.co.uk/
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Groundwater Levels
Water supplies for most of Hertfordshire come from sources deep below ground level called aquifers, from which water is extracted through boreholes. Groundwater levels vary throughout the year as a result of the amount of rainfall penetrating through to the aquifer to “recharge” it. Most recharge is made in the autumn and winter months, giving rise to the highest groundwater levels around April, and lowest levels usually in October.
After the extremely dry winters of 2004/05 and 2005/06 (with over 20% less rainfall than average), good winter recharge in 2006/07 (around 20% above average) and the following very wet summer allowed groundwater levels to rise and remain above average throughout 2007, 2008 and most of 2009. However, the dry conditions of September and October 2009 delayed the onset of recharge, and groundwater levels dropped slightly below average for the time of year.
Whilst it is unlikely that restrictions on water supply will need to be imposed in 2010, water companies will continue to liaise with the Environment Agency (EA) to maintain a close watch on the situation.
Groundwater Levels at Lilley Bottom - January 1995 to October 2008
Source: Veolia Water Three Valleys November 2009 central.veoliawater.co.uk
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Veolia Water Three Valleys Activities 2009
The company, which supplies most of the county’s water, has wide responsibilities to its customers, business partners, the community and the environment – and aims to conduct its activities with these in mind.VWTV carries out over 400,000 water quality tests every year. Of those that were measured against the Drinking Water Inspectorate’s standards, 99.98% were compliant.
- The company has invested in world-leading treatment processes, monitoring systems (such as leak detection) and network maintenance to help sustain the quality and supply of water.
- VWTV works closely with the Environment Agency, DEFRA and others to manage Hertfordshire’s water sources in the face of a growing population and the effects of climate change.
- The company promotes ways to save water around the house and in the garden.
- Through the company’s education programme, more than 18,000 school children, many from Hertfordshire, learnt to become more water efficient.
- By corporate sponsorship and staff fundraising, VWTV donated around £80,000 to local charities and community organisations.
- The company continued to maintain conservation areas on its land, such as Stocker’s Lake Nature Reserve near Rickmansworth.
Indicator WR2 - River Quality
In 2008 the chemical quality of Hertfordshire’s rivers improved from 66.63% in the ‘very good or good’ category to 72.59%. Looking at historical data, this shows that the quality is comparable to the year 2000 (72.44%), a particularly good year for river quality.
River quality
Source: Environment Agency November 2009 www.environment-agency.gov.uk
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A further 23% of river length is achieving ‘fairly good’ or ‘fair’ quality, which is a decrease from the previous year’s value of 28%. A total of 95.39% of river length in Hertfordshire are of good or fair quality. Compared to the previous two years this is an increase, but a decrease compared to the 100% in 2000. Whilst 4.61% of river length was classified as ‘poor’, a 1% decrease compared to last year, still no river lengths were classified as ‘bad’.
As of last year the EA no longer monitors Biochemical Oxygen Demand (BOD). BOD is the amount of dissolved oxygen in water that is consumed through the microbiological oxidation of biodegradable organic matter present in waters. This is measured under test conditions and over a period of usually five days. It is one of the standard tests used to characterise effluent quality. This means that we no longer have data for indicator WR3 – River Quality Objective.
At the same time the EA also had to reduce its monitoring network. Both changes had an impact on indicator WR2. The data that is shown in the graph above has incorporated these changes, for both the 2008 and the historic data.
Over 2009 there were a number of projects successfully completed by the various agencies and organisations with responsibility for improving and protecting Hertfordshire’s water quality. One such project was carried out at Sabey’s Pool.
Restoring the bank at Sabey’s Pool
Sabey’s Pool in Rickmansworth is a mixed still-water fishery leased from British Waterways by West Hampstead Angling Club. Historically, the fishery was separated from the adjacent River Chess by a 50-metre corrugated iron and chain-link fencing barrier. Until recently this was in a state of disrepair, which meant that fish could move freely between the river and the pool.
Because the River Chess is a chalk stream and, as such, a national category one Biodiversity Action Plan habitat, a large influx of coarse fish could have damaged this habitat. In addition, the amount of fish movement meant that disease was more likely to enter the fishery.
Sabey’s Pool before…
In February 2009 Cain Bio-engineering Ltd and the County Council’s Countryside Management Services (CMS) created 50-metres of naturalised bank. This separated Sabey’s Pool from the river to stop the transfer of fish and water, and to protect the chalk stream habitat.
Speaking of the new bank, Matt Hart (Environment Agency) said, “We have a basket filled with local indigenous plant species to provide a natural and fully vegetated bankside habitat. We have also erected a permanent two-sided netting arrangement to protect the plants from roosting birds, and to prevent coarse fish species migrating into the Chess when the waters are high.”
…and after work completed by EA, CMS and contractors