Calibrating and Evaluating
the Phosphorus Indicators Tool (PIT)

Calibrating and Evaluating the Phosphorus Indicators Tool (PIT)

Funder: DEFRA

Cost: £188k

Duration: 2001-2005

Project Overview
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Results and Applications
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The PIT project is part of a suite of tools being developed to allow the Department for the Environment, Farming and Rural Affairs (DEFRA) to estimate phosphorus losses from soils to surface water. These tools are vital if DEFRA is to effectively target policy to control diffuse pollution. The PIT project provides a 'broad-brush' approach to identifying areas where phosphorus losses to water are likely to be high. Using public data at a relatively coarse resolution (1 km2) the PIT methodology allows large areas (regional to national scales) to be investigated. The results from the PIT model can then be used to identify areas for more intensive investigation at a finer scale, feeding information into other tools that are being developed to identify the risk of P loss to water such as PEDAL and NUPHAR ( CEH NUPHAR site)

The aim of this project was to identify appropriate indicators of the sources of P and pathways of transfer that may lead to the delivery of P from agricultural land towards watercourses. The objective was to integrate these indicators within a single calculation system or model to predict the spatial variation in the risk of P loss.

To do this, the model needed to:

  1. be able to respond to changes on both agricultural land use and management and to environmental factors

  2. be structured in such a way that the individual parameters and stages of calculation have physical meaning based on field measurements

  3. use data that are readily available at the catchment scale (for any catchment in England and Wales)