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What is Catchment Management?

Portsmouth Water abstracts groundwater found within the Chalk rock of the South Downs to supply public drinking water in your area. Around 85% of the water we supply comes directly from groundwater, sourced from boreholes or springs, with the remaining 15% being derived from the river Itchen - itself being groundwater fed.

The water we supply to our consumers has to meet strict drinking water standards which provide specific limits on a number of pollutants, including nitrates and pesticides. The quality of water abstracted from our sources is influenced by the land practices in our catchments, such as the use of artificial fertilisers which are predominantly derived from agriculture.

The traditional ‘end of pipe’ solution for dealing with these impurities is to build large treatment works. However, these are expensive to construct and operate and do not provide benefit to either the environment or our customers.

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Portsmouth Waters specific aims for catchment management include:

  • To protect public health by preventing nitrate concentrations at a source rising above the drinking water standard.

  • To keep nitrate concentrations low

  • To delay the point at which nitrate concentrations at a source exceed the drinking water standard and hence delay the need for treatment.

  • To reduce the degree of treatment that may be required in the future at a source, hence lowering costs.

Portsmouth Waters catchment management schemes

We offer grants to farmers to help reduce nitrate leaching in our priority catchment areas.
We offer advice and workshops to people in the equestrian industry on best practices for a healthy horse and environment
We offer grants to houses with oil tanks to reduce the risk of spills within the catchments for our abstraction points
We work to enhance the biodiversity on all of our sites and also offer grants to enhance the habitat network around our sites

Planning Applications

We ask that Local Planning Authorities consult us on planning applications within our catchment so we can assess whether they pose a risk to groundwater quality. We try our best to offer solutions to groundwater quality issues, offering recommendations to protect our water supply.
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Catchment management also provides wider benefits to the environment such as:

  • Reducing nitrate entering groundwater and surface water, including protection of Hampshire’s internationally important chalk streams.

  • Limiting nitrate inputs to transitional and coastal waters which may be at risk of extreme algal growth (eutrophication).

  • Helping to protect and increase biodiversity within a catchment.

  • Helping to meet objectives of the south downs national park, especially in relation to improving water quality. For example, the south downs nature improvement area overlaps several water source catchments with rising nitrate trends.

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