Memorandum submitted by Dr Keith Weatherhead
CLIMATE CHANGE AND WATER SECURITY
The evidence below is based on my experience
gained through my personal research, as a CAMS stakeholder Group
chairman, my involvement with the UK irrigation industry (I am
currently chairman of the UK Irrigation Association), and leading
a series of recent university research projects, particularly:
— National and Regional Water Resource
Strategies: Forecasting spray irrigation demand (England and Wales)
to 2025 (funded by the Environment Agency).
— Optimum Water Use for Industry and
Agriculture, (agriculture section) (funded by the Environment
Agency).
— Climate change and Demand for Water;
CC:DEW (agriculture section) (funded by Defra).
— Sustainable Water Resources: a framework
for assessing adaptation options in the rural sector. (A Tyndall
Centre for Climate Change Research project, NERC/ESRC/EPSRC funded).
(Leading the consortium comprising Cranfield, UEA, Nottingham,
and Southampton Universities).
The views expressed are my own, and do not necessarily
agree with those of Cranfield University or any other organisation.
PREAMBLE
1. My responses specifically relate to irrigation
water resources for agriculture.
2. I have taken it as given here that the
irrigation of high value crops in England and the downstream businesses
it supports are economically important in many areas for rural
development and employment, and are environmentally sustainable
compared to the likely alternatives such as importing these crops.
Whether existing water supplies are adequate,
and what additional sources of water might be needed
3. Existing water supplies are under serious
stress. Additional abstraction licences are already unobtainable
in large parts of eastern England, where the need for irrigation
is concentrated. Many catchments are being classified as over-abstracted.
To comply with existing environmental legislation, the Environment
Agency currently estimates it will have to pay over £300
million up to 2012 in compensation for curtailing or revoking
existing non water company licences, to be funded from charges
on continuing abstractors. No compensation will be paid after
2012. Irrigators are understandably extremely worried about the
future security of their existing water resources, and the future
cost of their water.
4. Meanwhile, irrigation water demand is
currently growing at 2% to 3% per annum. Demand continues to grow
under the most probable future scenarios without climate change.
The Climate Change and Demand for Water project (CCDeW) forecast
that climate change would increase irrigation water demand by
a further 20% by the 2020s and by 30% by the 2050s, even allowing
for the offset from higher yields due to higher atmospheric carbon
dioxide.
5. Clearly this additional water is not
available from existing sources. Furthermore, climate change,
in eastern England at least, is likely to reduce summer flows
and recharge into aquifers.
6. Some licensed but unused water may become
re-available under licence trading, but the environmental impacts
of abstracting it are uncertain. On-farm reservoirs storing winter
water are feasible in some catchments, but at a significant cost
to the users and the national economy. Other responses will have
to be moving from lower to higher value uses, more efficient application
and better scheduling. Desalinisation, re-use of effluent (other
than by re-abstraction from rivers) and other exotic solutions
are unlikely to be major new sources for agriculture.
What will be the impact on resource management
(and particularly the need for changes in irrigation and water
conservation for agriculture.)
7. Clearly water for agriculture is going
to become scarcer and more highly valued. Even if new sources
are constructed, the water will be relatively expensive.
8. Higher value and limited water will restrict
irrigators even further towards irrigation of the highest value
crops—mostly potatoes, vegetables and soft fruit for supermarkets.
Irrigation of low value crops, such as grass and cereals, has
already largely disappeared, and the irrigation of sugar beet
is marginal.
9. Higher value and limited water will also
encourage irrigators to move towards better application methods,
better irrigation management and better scheduling. The government
and Agencies can play an important role in facilitating and encouraging
these moves, eg by supporting research, training and information
dissemination. The support of the Defra and the Agency for the
national Agricultural Water Resources Group, and the Agency's
willingness to deal with abstractor groups rather than individual
licence holders has been positive.
10. There does appear to be an opportunity
to take a whole-catchment (or sub-catchment) view of irrigation
water resources that is currently missing. (Some of our research,
for example, has suggested that larger reservoirs on clay land
can be a better solution than multiple small on-farm reservoirs,
which are often on lighter soils and often have to be expensively
plastic-lined.)
11. Resource management needs to be highly
flexible to allow these adaptive changes to occur. Licences should
not remain locked up on farms that no longer need them, or have
only low value uses. The move towards tradable abstraction licences
is to be welcomed in that respect, though we still await details
for the Agency and there are fears that the mechanisms adopted
may be too restricted to be workable.
12. The Environment Agency is keen to promote
sustainable water use and "efficiency" (the definition
of this for crop production remains a matter of debate). There
is however a risk that the Agency could become over-involved in
on-farm decision making, eg by specifying irrigation method or
cropping and/or too focused on water use at the expense of other
aspects of sustainability. Generally, I believe trading and increasing
efficiency will work better if the Agency adopts a guiding role,
setting criteria and standards, but does not try to micro-manage
the details.
The implications for flood management, investment
in mitigation measures, and for wider policy such as planning
13. No specific comments.
Ways in which the impact of changes in water availability
on biodiversity can be minimised
14. It is clear that decreases in summer
river flows, alongside increases in water demand, will lead to
conflict.
15. The arrangements being out in place
by the Environment Agency under the CAMS initiative, supported
by various European legislation transposed into UK law, provides
a strong basis for protecting flows and habitats without climate
change. The environmental needs will be protected by restricting
abstraction, to retain a hands-off hydrograph meeting environmental
needs. Environmental protection is widely supported by agricultural
abstractors.
16. What is less clear is how water availability
and bio-diversity can both be protected if summer flows decrease
under climate change. If the environmental need is initially fully
protected, all abstraction will be disproportionately squeezed
and eventually stopped. If drinking water supplies are given absolute
priority, the agricultural abstractor will be even worse affected.
And in the long-run, the river environment will have to adapt
to climate change anyway. This suggest it may be better to progressively
change the environmental flows to match climate change, and work
to allow nature to adapt more gradually.
Dr Keith Weatherhead,
Senior Lecturer, Water Resources Management,
Institute of Water and Environment,
Cranfield University.
April 2004
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