Nutrient Neutrality -Hydrogeological Assessment (HGA) of a site within Lyscombe, Dorset

Descriptions

The objective of this project is to develop a detailed hydrogeological assessment to understand the potential of using a proposed site near Lyscombe within the Poole Harbour Catchment, Dorset, as mitigation against nutrient loading. There is a need to understand the balance between overland and subsurface flow pathways within the proposed site as this balance will determine the time lag for N and P to reach a surface waterbody. A hydrogeological assessment is thus required to explore what sort of time lag may be observed from the cessation of agriculture to the beneficial effects of the reduction of N and P. The Hydrogeological Assessment must: •Include an assessment of the potential for overland flow at the site. •Include an assessment to determine the potential time lags for subsurface flows and their associated nutrient loads in reaching the designated site, Poole Harbour. •Show consideration of the infiltration potential of the site to allow for determination on the proportion of rainfall that will follow either surface or subsurface pathways to the nearest surface waterbody. •Define the time taken for the nutrient reduction, once implemented, to have an effect at the designated site. •Be based on the best available evidence. While these are the key deliverables for this contract it is anticipated that the supplier may choose to improve upon and expand these initial requirements. Purpose of this Contract To support the Nutrient Neutrality project's habitat delivery enabling Natural England, landowners and other interested parties to understand constraints and likely costs of progression towards the design and build phase of schemes. Aims of this Contract To provide adequate information for Natural England and the landowner to understand the potential time lag that may occur between the cessation of agriculture to the beneficial effects of the reduction of N and P.