Global Climate Change Part 4 – Preparing For The Future
In this, the last of H2Bid’s series on the effects of climate change, the options
for action will continue to be explored. As mentioned in the third article,
surprisingly little effort has gone into preparing for climate change even
though most scientists agree that even the aggressive greenhouse gas
emission targets proposed for the Copenhagen Climate Conference in 2009
will have little, if any, measurable effect on the current global warming trend.
The last article suggested some general preparations that could minimize
potential negative outcomes of climate change; this article will discuss specific
actions that water planners, hydrologists and regional managers could take to
protect the water resources in their areas.
If any one theme was meant to be conveyed in this series of articles, it was
that climate change will mean change. Change in and of itself is neither good
nor bad, but change for those who are unprepared will almost always result in
a poor outcome. Long-term water planning choices, such as the design and
construction of new water-supply infrastructure, agricultural planning, urban
water allocations and rate structures, and reservoir operating rules all depend
on climatic conditions; if these conditions change, the choices must change as
well. More appropriately, if the planning choices could begin to change ahead of
the climate, much more favorable outcomes should result.
Normal reservoir levels are based in part on the historical average rainfall for a
given area. While this has historically worked for most regions, one needs only
look to California’s current water shortfalls to appreciate the risks of assuming
that rainfall rates will never change. If the freakish and unpredictable weather
that affected medieval Europe during the Little Ice Age was to happen in modern
times, water planners would, of course, want to take full advantage of the heavy
rains when they may occur, rather than letting the excess water pour out the
spillways of their dams. By capturing more rainfall when it occurs, it will leave
these regions in an improved position should the rainfall frequency diminish.
Regional managers may want to consider several options for increasing the capacity
of their reservoir systems. If the opportunity exists to create additional reservoirs
in a region, it should be proposed as a project with high potential payoff.
Alternately, in areas with earthen or moderately reinforced dams, it may be
possible to raise the height of the dam and create a new spillway for the new
maximum planned reservoir depth. Even an increase of 3 meters (about 10 feet)
could mean a huge increase in the holding capacity of many small, local reservoirs.
For those planning new construction, consider not relying completely on the
local historical minimums, maximums and averages. Rather, consider various
“climate what-if†scenarios. Looking at what effects might happen with
prolonged 25% or even 50% variations above and below the historical rainfall
norms will offer key insights into what plans might offer the “biggest bang for
the buck†over the coming decades. Additionally, look at recent rainfall trends,
over the past decade or two and compare those to the historical patterns. If a
recent trend shows some major departure from the historical pattern, perhaps it
should be factored into the plan.
Working with agricultural outreach programs, common sense farming techniques
and new innovations should be stressed. Drip agriculture, drought-resistant
crops and land use planning will all play important roles in maximizing crop yield
while minimizing water use. Experiments involving large-scale use of drip
agriculture in China show that it could reduce agricultural water demand by
more than 50%. Additionally beneficial to both farmers and watershed managers,
drip irrigation has recently been shown to reduce fertilizer runoff by 95%.
Also critical for water systems near coasts, it will be important to protect fresh
water sources from sea water infiltration. Groundwater pressure barriers may be
useful in stopping infiltration into wells and aquifers. Developing and enhancing
the barrier wetlands will help to protect the river and lake systems just inland from
the coast. These buffer areas should be managed in a way that allows for their
inland expansion to match the predicted sea level rise.
Certainly none of these options are inexpensive or easy; but as stewards of our
local water resources and systems, it is our collective responsibility to plan for
the success of those systems. It should be well understood that regions which
anticipate and plan for the effects of climate change will fare much better than
regions which do not. Taking that point one step further, those regions which
have planned well and positioned themselves well, should expect to see increased
economic prosperity and growth as a result of their stable water resource position.
The opposite is likely to be the outcome for the under-prepared. That argument
should be at the center of the planning debate that will certainly ensue when
planners and engineers take their ideas to their governments and citizens.
Assuming that the weather patterns that have been in place for the past 50 to
100 years will always be in place is simply unreasonable. The climate of our
planet is constantly changing and we must change our attitudes with it.