The UKWIR methodology for the determination of outputs of groundwater sources: a review

The UKWIR methodology for the determination of groundwater source outputs was developed in order to provide a standard, relatively simple and auditable means of assessing outputs from the wide range of groundwater source types and aquifers in the UK for a variety of water level and demand conditions. New case studies are presented which illustrate aspects of the:methodology and its flexibility The cases derive from use of the methodology by the author at over 150 well sources in response to the Environment Agency's 'Reassessment of Water Company Yields'. The methodology can be adapted to include refinements, such as transposition to account for changes in regional abstraction, the use of a pump curve instead of a single value of pump capacity, and adaptation of the: analytical approach to allow for unequal pumping from wells at a multiple source. Topics for discussion include: choosing between the options, the plotting or operational bounding curves, definition of the deepest advisable pumping water level, data requirements, refinements to the analytical approach, drought and demand, determining the average day peak week, the group licence constraint, and assessment gradings.