Catchment descriptors to optimise hydrometric networks

Operational needs commonly dictate the evolution of
hydrometric networks. Such an approach can fail to meet
long-term water management information objectives.
This paper investigates how spatial descriptors can be
used to assess the strategic value of individual catchments
in the UK gauging station network. A catchment utility
index (CUI) is presented based on an automated
implementation of the Flood Estimation Handbook
pooling-group procedure for assessing catchment
similarity. The CUI is derived from the frequency with
which gauged catchments across the UK are called in the
pooling-groups for around four million catchments.
Several case studies illustrate how the index is interpreted
and used—in combination with the hydrometric
performance of gauging stations and the degree of
disturbance to the natural flow regime—to identify the
most strategically useful gauged catchments. Such
information is an essential component in guiding network
evolution and in improving the effectiveness of
procedures to estimate river flows in ungauged
catchments.