Hydrological Connectivity - a study into representative metrics for
a humid temperate catchment in northern England.

Abstract

Hydrological connectivity has been identified as a concept which can help hydrology move
towards a hydrological approach focussing on homogeneity rather than difference. The method of
hydrological connectivity measurement has subsequently developed as key in permitting this
concept to reach its potential. Previous studies have focused on topography and soil moisture
respectively to solve this problem, generating metrics and indexes in order to predict the
potential for connectivity spatially and temporally. This study focused on ascertaining the relative
success of these different approaches for a humid temperate catchment in northern England. It
was found that simple saturated area based metrics performed better than complex cluster
analyses. In addition to this the Topographic Wetness Index was found to struggle to ascertain
active areas within the catchment. Subsequently, building upon the Network Index of Lane et al.
(2004), a new index was developed in order to combine topographic and soil moisture
measurements to give a probabilistic estimation of connectivity over time. This Cumulative
Probability Network Index was found to be the most promising method for estimating
hydrological connectivity, particularly for upland catchments with shallow soils.