WINEP Case Study: SES Water

River Mole and Leatherhead Groundwater Interaction Nitrate Investigation

Like many water companies across the UK, high and deteriorating groundwater nitrate trends pose a challenge for SES Water. Chalk groundwater sources around Leatherhead are particularly impacted, with nitrate concentrations gradually increasing over the past couple of decades. Building on work conducted 2020-2025, focused specifically on nitrate in the groundwater catchment, this investigation will consider the influence of the wider River Mole surface water catchment on nitrate in the Leatherhead groundwater.

As part of this investigation SES Water are partnering with local charity River Mole River Watch, providing portable nitrate monitoring equipment for their volunteers to conduct monthly monitoring at 30 strategic locations across the River Mole catchment. This data will assist in River Mole River Watch’s campaign to improve the ecological state of the River Mole and will also be used in SES Water’s investigation alongside SES Water’s own monitoring data. Findings from catchment walkovers and hydrogeological modelling will be used to identify sources of nitrate in the River Mole surface water catchment and understand the pathways by which the wider surface water and groundwater catchments interact.

The investigation will be used to assess the need for catchment-based measures in the wider River Mole surface water catchment to address nitrate pollution in the Leatherhead boreholes. It will also help form a list of potential cost-effect catchment measures to prevent a deterioration of the groundwater nitrate trend.


Other Examples:

There are over 60 other investigations included in the WINEP into water quality within Drinking Water Protected Areas. These aim to identify actions to prevent deterioration and/or reduce treatment requirements of abstracted water by reducing inputs within the catchment upstream.

Another example of an investigation includes Thames Water’s Cleeve catchment investigation to identify areas that are high risk for nitrates getting into the groundwater, including investigation into the potential impacts of farming practices in the catchment. The aim is to use this investigation to inform a catchment management plan to reduce inputs of nitrate.

(Banner image of River Mole, photo detail by Andy Scott - Own work, CC BY-SA 4.0)

River Mole and Leatherhead Groundwater Interaction Nitrate Investigation

Like many water companies across the UK, high and deteriorating groundwater nitrate trends pose a challenge for SES Water. Chalk groundwater sources around Leatherhead are particularly impacted, with nitrate concentrations gradually increasing over the past couple of decades. Building on work conducted 2020-2025, focused specifically on nitrate in the groundwater catchment, this investigation will consider the influence of the wider River Mole surface water catchment on nitrate in the Leatherhead groundwater.

As part of this investigation SES Water are partnering with local charity River Mole River Watch, providing portable nitrate monitoring equipment for their volunteers to conduct monthly monitoring at 30 strategic locations across the River Mole catchment. This data will assist in River Mole River Watch’s campaign to improve the ecological state of the River Mole and will also be used in SES Water’s investigation alongside SES Water’s own monitoring data. Findings from catchment walkovers and hydrogeological modelling will be used to identify sources of nitrate in the River Mole surface water catchment and understand the pathways by which the wider surface water and groundwater catchments interact.

The investigation will be used to assess the need for catchment-based measures in the wider River Mole surface water catchment to address nitrate pollution in the Leatherhead boreholes. It will also help form a list of potential cost-effect catchment measures to prevent a deterioration of the groundwater nitrate trend.


Other Examples:

There are over 60 other investigations included in the WINEP into water quality within Drinking Water Protected Areas. These aim to identify actions to prevent deterioration and/or reduce treatment requirements of abstracted water by reducing inputs within the catchment upstream.

Another example of an investigation includes Thames Water’s Cleeve catchment investigation to identify areas that are high risk for nitrates getting into the groundwater, including investigation into the potential impacts of farming practices in the catchment. The aim is to use this investigation to inform a catchment management plan to reduce inputs of nitrate.

(Banner image of River Mole, photo detail by Andy Scott - Own work, CC BY-SA 4.0)

Page published: 29 Jan 2025, 04:09 AM