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Phosphorus Export Risk Matrix: Example 3

Example 3

Groundwater dominated system with low-medium risk of phosphorus reaching receiving channels.

Many of the factors influencing nutrient loss in surface water systems are the same for groundwater systems. In the diagram below a groundwater system is considered as an area with high infiltration soil, usually without land drains, underlain by porous bedrock such as chalk, limestone or coarse sandstone.

High risk of phosphorus reaching the surface water corresponds to sites where the regional aquifer (water table) is sometimes in hydrological connection with the surface water channels. This may be due to large fluctuations in water table level or because there is a shallow (perched) groundwater system. In the above example the shallowest water table is in direct connection with the channel at certain times, e.g. during large storm events. A high risk would also result from perched water tables forming during storm events giving rise to rapid but temporary lateral connection of the hillslope with the surface channels.

Note. This system may also be loading the regional groundwater with nutrients.

medium risk medium risk medium-high risk high risk high risk high risk high risk very high risk very high risk very high risk
medium risk medium risk medium risk medium-high risk high risk high risk high risk high risk very high risk very high risk
medium risk medium risk medium risk medium risk medium-high risk high risk high risk high risk high risk very high risk
medium risk medium risk medium risk medium risk medium risk medium-high risk high risk high risk high risk high risk
medium risk medium risk medium risk medium risk medium risk medium risk medium-high risk high risk high risk high risk
low-medium risk medium risk medium risk medium risk medium risk medium risk medium risk medium-high risk high risk high risk
low-medium risk low-medium risk medium risk medium risk medium risk medium risk medium risk medium risk medium-high risk high risk
low risk low risk low-medium risk medium risk medium risk medium risk medium risk medium risk medium risk medium-high risk
very low risk low risk low risk low-medium risk medium risk medium risk medium risk medium risk medium risk medium risk
very low risk very low risk low risk low-medium risk low-medium risk medium risk medium risk medium risk medium risk medium risk



Groundwater dominated system with low-medium risk of phosphorus reaching receiving channels


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© C J M Hewett, 2004 © University of Sheffield, University of Newcastle upon Tyne & Lancaster University 2001, 2004 and 2005
Last updated March 2005

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