Poole Harbour nitrogen offsetting scheme

We are using catchment management to offset nitrate contained in the effluent discharged from Dorchester’s water recycling centre.

About the scheme

The scheme began in 2015/16 with the aim of reducing the amount of nitrogen entering Poole Harbour by 40 tonnes per year by 2020 through working with local farmers.

We achieved this goal in 2016/17 preventing 60.4 tonnes of nitrogen from entering the harbour. For the five years that followed, we continued to surpass this target.


Graph Showing Tonnes Of Nitrate Saved BY WW Dorchester WRC
Tonnes of nitrate saved per year by Wessex Water Dorchester water recycling centre nitrate offsetting scheme

Why did we choose catchment management?

Agriculture contributes to 66% of the nitrogen that enters Poole Harbour compared to the 12% that comes from our water recycling centres (WRCs).

By working with farmers in the catchment, we have been able to invest in agricultural measures that reduce nitrate leaching and provide wider environmental benefits, such as biodiversity improvements.

The alternative, installing nitrate removal plants at WRCs, only deals with nitrate and doesn’t deliver wider environmental benefits.

It would also be far more expensive, in addition to releasing significant quantities of carbon into the environment.

How do we support farmers?

We work with the farmers in a targeted area of the Poole Harbour catchment to:

  • identify and raise awareness of water quality issues
  • share the results of water, soil, crop and manure testing that we have carried out for them
  • provide advice and information on ways to improve the efficient use of key inputs
  • compensate farmers (where appropriate) for adopting alternative practices.

Within the catchment, there are groundwater safeguard zones where we also work with farmers to protect drinking water quality.

For more information about the scheme, please email adrian.moore@wessexwater.co.uk.