Case study CaseSouth Study joined upprotected landscapes”. Paper of “bigger, better, more UK Natural Environment White schemes set up to deliver the Area (NIA), oneof twelve Way Ahead Nature Improvement the banner of Downs the South The project was initiated under Chalk aquifer beyond. Nature Improvement Area and Downs NationalParkthe South how to mitigate these risksin pollution of groundwater and identify the risk of nitrate Modelling Project sought to Downs Collaborative Nitrate and coastal waters. The South fed by nitrate in transitional coast by increased algalgrowth tidal habitats along the south deterioration of protected inter- moreand, recently, to the river waterused for drinking treatment of groundwater and increasedhas need for the aquifer over the past60 years Rising nitrate Chalk inSouthern Background Nitrate ModellingProject Improvement Area –Collaborative Downs South Way Ahead Nature is areason to take noaction. changes inlandmanagement response of groundwater to perception thatslowthe very sector and to alsocounter the bias towardsagricultural the environment to avoid perceived sourcesofnitrate to the water needed to cover allpotential The evidence baseproduced catchment-based approach. wider benefits of following a quality would takeand the long improvements in water needed partners to know how in thefuture,and project the risk from nitrate pollutionnow Tohowplan to dealwiththe to water quality deterioration. reverse groundwater andsurface leaching from soilsare enough to practices to reduce nitrate sustainable landmanagement to persuade stakeholders that to provide compelling evidence The mainproject objective was Project • • to identify: groundwater were carried out the sources of nitrate in A seriesof desk studiesinto to within acceptable levels. improvements to reduce nitrate times, there may stillneed to be improved compared to past management practices have Although current land supplies andincoastal waters. ends upatpublic water from soils;andhow the nitrate of how muchnitrate leaches aquifer basedoncalculations the behaviour of nitrate in the as baseflow inrivers; water via solution features and groundwater andsurface betweenthe connections south coast of . towardsand the fed rivers andstreams drain Isle of Wight. These Chalk Levels, and the CuckmereOuse, Lavant, and the Rivers Itchen, Test, Adur, beneath the catchments of Chalk aquiferthe Southern The project area covered Location: Water Southern PortsmouthWater, (SSD), Water Partnership (CSF), and Harbours Clean Park Authority,Downs Downs National South Project Steering Group:

The project worked through phases of risk mapping and scenario development, identifying both problems and solutions. Cost benefit modelling of solutions including land use change, livestock management, fertiliser management, manure management and organic farming were used to guide recommended mitigations. An ‘advice programme’ to instigate wider behavioural change was also implemented. Feedback and discussion of project results from a stakeholder workshop included how to communicate the work to a non-technical audience and the Catchment management was In the spirit of sharing learning wider environmental benefits of identified as more cost-effective to a wider group, the outputs future work. compared to chemical treatment from the project were shared in most groundwater drinking with the BGS for use as a case Outcomes water catchments over a 40-50 study in the report “Modelling The project provided partners year period. the nitrate legacy” Groundwater with an evidence base covering Science Directorate Open Report point and diffuse sources of Lessons learnt OR/15/00. 2015. nitrate from national and Completed in 2013/14, project In rolling out the findings of the water company datasets, results have guided subsequent work on the ground the following local expertise and farm visits NEP work by were identified: to produce a representative Water and , output that could confidently be and the proposal of innovative • For voluntary measures to discussed with stakeholders. catchment measures for ’s be effective they need to be Price Review 19 (2020-2025). attractive and effective to A nitrate budget for The project provided evidence convince farmers and land groundwater in each catchment for the ChaMP project managers. was calculated, and the sectors highlighting that on average the contributing to the highest • In developing measures with current nitrate loading across concentrations identified. farmers to address nitrate, the Brighton Chalk exceeds the keeping things simple by Predictions of if, when and for WFD threshold of 37.5 mg/l NO3. addressing nitrate loss across how long nitrate will exceed The wider benefits of measures the whole farm allows farmers the drinking water standard to address nitrate concentrations and their agronomists the were made, using an approach in groundwater have been freedom to work out a system that can be explained to assessed by , to comply with limits. non-experts, to help future including a better understanding supply management by water of the costs and benefits of companies. woodland planting. Zones of faster-flow paths Both Portsmouth and Southern were identified to help focus Water have looked at ways action to control spikes in nitrate of identifying the location of concentration at a shorter surface karstic features in timescale than usually identified the Chalk aquifer which could for groundwater, giving short to provide rapid pathways to medium term solution for the groundwater abstractions and water companies. have worked in areas prone to rapid flow paths to raise awareness of risks to drinking water. Next steps • Further cost benefit analysis for nitrate measures effectiveness at Portsmouth Water’s groundwater abstractions has supported the focus of farmer engagement and discussion of which measures are feasible. • Refining the input to the nitrate budget from historic dilute and disperse landfill with Environment Agency and Local Authority monitoring records, as some of these historic sites may still contribute nitrate to groundwater. • Further work on mapping karst and understanding how the risk of pollution through potential rapid pathways (can be 10s Websites: of kms per day) can be www.southdowns.gov.uk/care-for/water/brighton-champ-for-water/ managed. www.cleanwaterpartnership.co.uk/

Contacts: • Jeremy Burgess – SDNPA • Alastair Stewart – Southern Water • Chris Manning, Polly Wallace and Frances Sinclair-Smith – Environment Agency • Simon Deacon – Portsmouth Water / Downs and Harbours Clean Water Partnership • Susie Roy – Wood

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