NVZ

Nitrate Vulnerable Zones (NVZs) were introduced by member states of the European Union following the ratification of the EC Nitrate Directive in 1991. These NVZs are areas of land which drain to waters where nitrate concentrations exceed, or are likely to exceed, the 50 mg/l level dictated by the EC Surface Water Abstraction Directive (1975). The areas designated can therefore be both groundwater and surface water catchments. NVZs may also be designated where it is deemed that nitrate concentrations are such that they will/could trigger eutrophication in fresh, estuarine, coastal or marine waters.

In 1996, the UK government designated 66 NVZs in England. Four of these were surface water catchments, several others had some surface water influences (e.g. River Hull and North Lincolnshire Wolds), but by far the greatest number were groundwater catchments.

The Government subsequently introduced an Action Programme aimed at reducing the loss of nitrate from the agricultural land within these NVZs. The Nitrates Directive requires that the effectiveness of this plan be monitored. Without long-term monitoring of nitrate losses from land prior to the scheme, probably the only way to assess the results is to examine the changes in farming practices brought about by the introduction of the Action Programme. Although the British Survey of Fertiliser Practice (BSFP) provides some information, it does not cover farmer attitudes to N fertiliser prediction, which must be addressed within the Action Programme. In any case, the BSFP covers the whole of the country and the sample of farms in the 1996 NVZs was not sufficiently large to allow reliable analysis. Therefore, in 1996 ADAS was commissioned by what was then the Environmental Protection Division of MAFF to conduct a survey of farms in the NVZs. During the winter of 1996/97, ADAS Consultants visited 955 farmers within NVZs and completed a questionnaire covering the aspects of farming that the Nitrate Directive, as it was interpreted at the time, required should be controlled within the Action Programme. That survey formed the benchmark against which to measure change. In 2003, ADAS was asked by Water Quality Division of Defra to conduct a repeat survey, to assess the change in the intervening years. It was assumed that many of the changes could be attributable to implementation of the Action Programme though, of course, other external pressures could also be responsible for some of the change.

As from 1 January 2009, the areas covered by Nitrate Vulnerable Zones (NVZs) were increased to approximately 70% of England. This includes the 55 per cent originally designated in 2002.

These NVZ area were and are being introduced to prevent diffuse water pollution.

Eplaination from the Defra website.

What is diffuse water pollution?

Some water pollution can be traced or attributed to a point of source, such as sewage treatment works or industries.

Diffuse water pollution, in contrast, cannot be traced or attributed to a precise point or incident. Rather, it is the cumulative effect of day to day activity over a large area. Various activities contribute to diffuse pollution, including agriculture, forestry, mining, construction and urban life. Pollutants deposited on land, roads and spaces are washed into watercourses by rain. Consequently, the local climate, geology and other natural phenomena can influence the size and extent of the problem. In agriculture, diffuse pollutants include silt from soil erosion, nutrients from the application of fertiliser or spreading of manure, and pesticides from the handling and application of the chemicals.

How does agriculture contribute to diffuse pollution?

No one farmer is responsible, and many are committed to protecting and enhancing the environment, but cumulatively diffuse pollution from farms is having a substantial impact on the quality of English waters.

• Around 60% of nitrate and 25% of phosphates in English waters originate from agricultural land.  Elevated levels of these nutrients are of concern because they can cause eutrophication, which harms the water environment. Also, excess nitrate has to be removed before water can be supplied to consumers.
• Agriculture contributes between 25 – 50% of the pathogen loadings which affect England's bathing waters.
• Up to 75% of sediment input into rivers can be attributed to agriculture. This reduces water clarity and causes serious problems for fish, plants and insects.
• Pesticides are contaminating drinking water sources, requiring expensive treatment at water works to remove pesticides before it is supplied to consumers.

 What is eutrophication?

Eutrophication is the enrichment of water by nutrients (such as nitrate or phosphate), causing an accelerated growth of algae and higher forms of plant life leading to an undesirable disturbance to the balance of organisms present in the water and to the quality of the water concerned.

The resulting disturbed aquatic ecosystem may:

• become an unsuitable habitat for other species such as fish and invertebrates. This reduces biodiversity of both the aquatic habitat and of other species in the food chain;
• become too low in oxygen for some species to tolerate, such as fish and shellfish;
• damage the quality of areas of high wildlife conservation value, such as Sites of Special Scientific Interest (SSSIs);
• produce toxic algal blooms which poison fish and shellfish, making them unsafe for people to eat and damaging the fisheries industry. However, there is as yet no well-established link between nutrient enrichment and the incidences of shellfish toxicity in marine waters. Local livestock and wildlife may be at risk and blooms in recreational waters can result in closure of the area, with impacts on tourism;
• produce so much vegetation that navigation or recreational use of waters becomes impossible. This also impacts on the tourism and leisure industry.

NVZ downloads:

• NVZ Map
• NVZ regulations (NVZ4)
• NVZ manure planning (NVZ5)
• NVZ record keeping check list
• NVZ field record sheet (NVZ3)
• NVZ Farm Waste Grant Scheme (NVZ8)
• NVZ Farm Waste Grant Scheme Application Form (NVZ7)

If you need any further information on NVZ's go to www.defra.co.uk