Environmental Engineering Reference
In-Depth Information
More problematic at a regional scale were water level declines ascribable to all
wells rather than some, and for which the initial remedy was deeper drilling or
boring. This triggered the energy dimension of the water-energy-food nexus, as it
became apparent that depletion may ultimately take land out of production more
due to increased pumping costs than to absolute scarcity. Some governments,
notably states such as Punjab in western India addressed this by subsidizing or
providing free electricity for irrigated farms, which only accelerated depletion, and
which few politicians have had the courage to reverse. The adjacent Punjab
province in Pakistan provides a valuable comparison, as it does not receive as large
an electricity subsidy or have as reliable an electric power supply, it has relied on
diesel pumping (Siddiqi and Wescoat
2013
). This has reduced water level declines
and helped sustain groundwater management. The
in central Cali-
fornia faces similar problems, particularly so in the grips of severe drought in 2014,
the consequences of which include dramatic areas of land subsidence, which
necessitate drainage and pumping and thus further increased energy costs.
These groundwater market failures are symptomatic of broader water-energy-
food nexus failures. Whereas surface water rights and uses were relatively easy to
de
'
third Punjab
'
ne, visually monitor and publically administer, groundwater development is
highly dispersed, located on individual lands, dif
cult to measure, and seemingly
impossible to administer. There is rarely a market in groundwater supplies, only in
their costs, and even these markets are often distorted or absent. This situation is
described in South Asia as
'
anarchic
'
(Shah
2008
), which may apply in many other
if not most regions of the world.
3.4 Wastewater Reuse for Peri-Urban Agriculture
Approximately 20 million hectares worldwide is estimated to be under agriculture
that relies on wastewater reuse (Rijsberman 2004). It has been argued that policy
support for encouraging wastewater reuse for agriculture after adequate treatment
would increase water use ef
ciency in agriculture. Some have even argued that
when wastewater is managed better, signi
ts can be derived in
developing countries through reuse for productive purposes like agriculture, kitchen
gardens and poultry rearing (Kurian et al.
2013
). Further, by encouraging fresh-
water swaps, wastewater reuse in agriculture could also potentially enhance source
sustainability of water supplies, especially to urban centres. A study in India also
found that effective wastewater reuse in agriculture had the potential to mine
organic nitrogen, potassium and phosphorus and thereby reduce the country
cant economic bene
'
s
reliance on expensive imports of fertilizers. But one speci
c knowledge gap that
prevents the realization of ef
ciency and productivity gains relates to a lack of
consistent and agreed upon water quality standards for different crop and produc-
tion systems. This knowledge gap constrains the development of standardized
policy guidelines that could facilitate wastewater reuse.
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