Land use, climate change and water availability: Phase 2a. Rapid Evidence Assessment: Results and synthesis

Houghton-Carr, H.A.; Boorman, D.B. ORCID: https://orcid.org/0000-0002-6436-5266; Heuser, K.. 2013 Land use, climate change and water availability: Phase 2a. Rapid Evidence Assessment: Results and synthesis. Wallingford, UK, NERC/Centre for Ecology & Hydrology, 45pp. (Unpublished)

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Abstract/Summary

This report presents the results from a Rapid Evidence Assessment (REA) to address the question “Can land use and land management make a difference to water availability?” Conclusions from this review are: • It may take many decades for the impacts of land use and land management practices on surface and groundwater resources to become apparent. • Trees never use less water than other vegetation, and usually use more water, leaving less water for surface runoff and groundwater recharge. Any land use/management intervention that promotes tree growth will use more water. Mature forests use less water than growing forests, and plantation forestry goes through stages, some of which (drainage and felling) can increase runoff and recharge. • The key messages from the biofuels articles are that there is no clear evidence about the water use of Miscanthus and switchgrass compared to traditional crops in the UK, but there is evidence that short rotation coppice (e.g. willow) can use very much more water than traditional crops. • Land use that leaves bare soil reduces evaporation and increases surface runoff or groundwater recharge. • Small (field) scale interventions to hold more water locally in the soil (e.g. tillage practices, soil treatments) are generally successful. This has the effect of reducing surface runoff and groundwater recharge, with the extra water being available for crops. • Some agricultural land use/management practices are dependent on very location-specific conditions, and are not regarded as replicable in other places. Other practices, whilst replicable, may not produce the same results because of different physical and climatic characteristics. Potential impacts of change may need to be considered on a case-by-case basis. • All of the above impacts are generally localised, with what appear to be large changes at the field, plot or sub-catchment level manifested as only small changes at the catchment or basin level. Concerning the process used to reach these conclusions the following recommendations are made: • The primary question and initial scoping to determine feasible search parameters are critical: future REAs should explicitly include stakeholder consultation from an early stage in order to better to understand the question. Focusing this review solely on UK studies would have significantly reduced the number of articles in the final set. To increase the number of UK articles, it would have been necessary to widen the search. • Future REAs should concentrate on a particular land use or land management intervention (e.g. tillage practices, certain crops, land drainage, etc), and on a particular hydrological or hydrogeological impact, which may facilitate a broader search and, thereby, consider more articles on that topic, or at a particular geographical location, within the time frame of the review. Land use, climate change and water availability: Phase 2a Results and synthesis iv It is further recommended that: • In order to generate a larger body of UK-specific evidence, there is a need for coordinated, targeted research and long-term monitoring to investigate the water-related impacts from the most important land uses and land management interventions, across a variety of catchment types. • There is a need to consider the impacts of land use and land management on water quality, as well as on water quantity.

Item Type:	Publication - Report
Programmes:	CEH Topics & Objectives 2009 - 2012 > Water > WA Topic 3 - Science for Water Management > WA - 3.2 - Assessment of available water resources in a changing world ...
UKCEH and CEH Sections/Science Areas:	Boorman (to September 2014)
Funders/Sponsors:	Department of Environment, Food and Rural Affairs (Defra), NERC
NORA Subject Terms:	Hydrology
Date made live:	25 Mar 2014 16:25 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/505418

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