Rethinking Infrastructure Design - Rethinking Infrastructure Design for Multi-Use Water Services - page 18

4.6 Droughts

4.6.1 Why Is Drought a Problem?

The implications of drought on a global scale are enormous. Not only is food
production endangered, but also fresh water resources are pressured. The envi-
ronment is changing. Risk of forest fires is growing and hydropower plants are

forced to reduce production or even temporarily shut down. Mostly droughts are
caused by lack of participation during winter. The level of moisture in soil is low
and the

first warm period in spring will lead to drought. This has severe conse-
quences for agriculture and the environment. Biodiversity is also in danger from
negative in uence of drought. Some of the flora and fauna species are dependent on

speci c humid ecosystem. With increase in temperature in urban areas, evaporation

increases as well. If not controlled, it will lead to increase in desiccation. Most of
the vegetation species in urban areas are not resilient to prolonged periods of
drought. Thus, irrigation is needed. This comes at the expense of already stressed
fresh water supplies. Long dry and warm periods are often followed with heavy rain
showers. Dried soil is not capable of absorbing water so the majority of rainwater
run-off over ows the sewers. Drought leads to decrease in groundwater table,

which in cities can result in damaging building foundations.

4.6.2 What Can Be Changed?

There are no standard solutions available for this problem. It is important that water
shortage problems in summer periods be taken into account while designing new or
reconstructing existing urban areas. Reducing the amount of impervious surface
and/or use of pervious materials that ensure water can in

ltrate the soil will help.
Generally, there is enough water; it only needs to be managed better. According to
MUS solutions, rainwater has to be harvested, stored and used during dry periods
together with recycled grey water and eventually black water.

4.7 Urban Agriculture

Urban agriculture is not a new development. After the urban boom following the
industrial revolution and during the twentieth century, the lack of food raised was a
problem. Today, 15 % of the world is food is produced in cities and it is estimated

that it has to be at least doubled within the next 20

'

30 years. During 2010, a world
agriculture report concluded that industrial agriculture is not capable of feeding
humanity. One of the biggest problems for agriculture is a lack of space, because of
rapid and uncontrolled urbanisation.

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