Predicting physical habitat sensitivity to abstraction

Laize, Cedric L.R.; Acreman, Mike. 2015 Predicting physical habitat sensitivity to abstraction. [Lecture] In: 5th International Multidisciplinary Conference on Hydrology and Ecology: Advances in Monitoring, Predicting and Managing Hydroecological Processes (HydroEco 2015), Vienna, Austria, 13-16 Apr 2015. (Unpublished)

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Abstract/Summary

A new version of the Rapid Assessment of Physical Habitat Sensitivity to Abstraction (RAPHSA) model was developed with a specific focus on operational applications. The original RAPHSA defined sensitivity to abstraction as the change in physical habitat with changes in river discharge. Several development needs were identified in order to deploy the model operationally, in particular: (1) Improving the representativeness of the calibration dataset - The original model was calibrated using a collection of PHABSIM studies totaling 516 transects at 64 river sites (ie stretches). This dataset is biased towards lowland permeable rivers. As a consequence, the geographical coverage and the river types captured by the model are limited. This issue was successfully resolved by analysing more than 4,000 potential additional sites in England and Wales with detailed hydraulic data, of which 90 were retained by applying a combination of criteria (eg proximity of gauging station, overlap of gauged flow and hydraulic data). (2) Simplifying the model - In order to standardise information across calibration sites, the original model uses flow percentile ranks, thus requiring the derivation of the flow duration curve prior to any run. The new version instead standardises with bankfull flow, which can be estimated from a single site hydraulic survey. In addition, fewer predictors are used. A Jackknifing procedure was run on both models, which performed very closely. The new RAPHSA has slightly higher mean squared errors, which is likely due to being calibrated on a wider range of river types than the original model.

Item Type:	Publication - Conference Item (Lecture)
UKCEH and CEH Sections/Science Areas:	Acreman
Additional Keywords:	ecohydrology, hydroecology, river flow, climate change, Europe
NORA Subject Terms:	Ecology and Environment Hydrology
Related URLs:	Publisher
Date made live:	21 Oct 2015 11:11 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/512025

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