OR/14/018 Background

Mansour, M M, Hughes, A G. 2014. Land Use, Climate Change and Water Availability: Preliminary modelling of impacts of climate change and land use change on groundwater recharge for England and Wales. British Geological Survey Internal Report, OR/14/018.

Introduction

These articles form part of the Defra 'Land-use climate change and water availability project Phase 2a' which has been funded by Defra, with co-funding provided by NERC via CEH and BGS. The project is a follow on project from the Environment Services to Sicen Partnership (ESSP) 'Can land use and land management make a difference to water availability under conditions of climate change: A potential way forward?' The work was undertaken by Cranfield University, CEH and BGS. It was split into three work packages:

• Task A — Conduct a systematic review of the evidence for the interactions of land use climate change and water availability [undertaken by CEH]
• Task B — Develop a range of plausible future land use, land management and growing season changes [undertaken by Cranfield]
• Task C — Undertake initial quantification, including establishing the baseline [undertaken by Cranfield and BGS]

Each work package has reported separately, this is the report for the BGS component of Task C: Initial quantification. The work describes in this report compliments that undertaken by Cranfield University for Task C. Their work used a point model, WaSim to simulate runoff and baseflow for a variety of soil types and climate scenarios (Holman and Hess, 2014). The results of the work have been collated into a single, summary document.

Work undertaken

Introduction

The work undertaken was split into two parts:

• the impact of climate change on recharge at a catchment and national scale; and
• the impact of land use change on recharge at a national scale.

The recharge and runoff modelling work was undertaken for the whole of England and Wales (Figure 1) and results have also been extracted for the catchments which have been the subject of other Abstraction Reform work: the Usk, Trent and Derwent, Hampshire Avon, Ely-Ouse, Dee, Stour and Tees, as well as the Thames Basin (Figure 2). The land use change assessment was undertaken using land cover mapping (LCM) data. The recharge model ZOODRM was used for all the simulations.

Future Flow and Groundwater Level dataset

This project has relied on the datasets produced by the Future Flow and Groundwater Level (FFGWL) project which was funded by Environment Agency, UKWIR and Defra and was undertaken by CEH, BGS and Wallingford Hydro Solutions Ltd. As part of this project, datasets were developed based on 11 Regional Climate Model (RCM) results: Had-RM3 using A1B 'medium' scenarios. However, the results from this model are produced at 25 km squares and are not spatially coherent. The FFGWL project has downscaled and bias corrected to produce daily 1 km² gridded datasets for Temperature, Precipitation and Potential Evaporation (Prudhomme et al., 2013). This produced eleven (a-k) model runs covering the period from 1950 to 2098 and whilst they don’t include particular historically recorded events (e.g. the 1975/6 drought), they are representative of the climate during that period, and subsequent simulated climate evolution. Further information can be found at https://www.ceh.ac.uk/sci_programmes/water/futureflowsandgroundwaterlevels.html.

Figure 1    Extent of the area representing England and Wales.

Figure 2    Locations of the eight catchment areas included in the study.

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