Drought Prevention

Drought is defined by National Geographic as "a period when more water is used than is replenished; thus causing a shortage." Managing fresh water as a sustainable resource is a balance between supply and demand; both human and natural factors are involved. Droughts are often triggered by a prolonged period of abnormally low rainfall, but the problems are also exacerbated by human activity. If neither the demand is reduced, nor the supply increased, then long term drought can have ecological consequences such as soil erosion, forest fires and crop death, as well as causing societal problems like stress, war, famine, disease and mass migrations. In the 20th century alone over 40 million people died due to famine caused primarily by drought. (Matthew White, Historical Atlas of the Twentieth Century, 2010.)

Engineers are vital to the prediction and prevention of drought, as well helping us to limit the damage these natural disasters cause to the local habitat and human population. So far, engineers have:

a) Discovered new SOURCES of fresh water (only 0.03% of world's total water supply), by:

- Drilling wells into aquifers to bring water to the surface

- Recycled water (creation of improved filters has allowed former wastewater to be treated and purified ready for use)

- Creating desalinisation plants to turn saline (salty) water into fresh so that it can be used for human consumption or crop irrigation

b) STORED water for both short and long term use by:

- Building dams and other gully-plugging structures

- Creating man-made reservoirs and other water storage facilities

- Constructing percolation ponds to recharge groundwater (small scale)

c) DIVERTED water by:

- Transvasement (re-directing rivers)

- Constructing canals and pipelines

- Landscape contouring

d) Prevented SOIL EROSION by:

- Using contour bunds, trenches and stone walls (small scale)

e) INCREASED rainfall by:

- Cloud Seeding

In the FUTURE, engineers could be able to:

a) Bioengineer water-resistant plants could help to reduce the dependence of farms on water to irrigate crops.

A feat of Engineering: The Hoover Dam

The Hoover dam was built to prevent flooding of low lying plains during the winter and spring, and to stop drought and water shortages in the 'dust bowl' states down-river in the summer and autumn. It is now self supporting; financed entirely through the sale of hydroelectricity generated at the dam. The Hoover Powerplant has an installed capacity of 2.08 million kilowatts.

The Hoover Dam Plan and an illustration of the works - circa 1935.

This map shows the Degree Unit area map location of Lake Mead.

Lake Mead is an artificial lake and an artificial reservoir created by the damming of the Colorado River.

The harsh lines through the lake represent the original course of the Colorado River

Spillway diversion tunnel under construction at Boulder Dam site - circa 1934.

Two unidentified workers, working for the Big Six companies stand in the underground water channel designed to accommodate at least a portion of the Colorado River in flood, or to prevent floods.

"Constructed during the Great Depression in the 1930s, the concrete arch-gravity structure was intended to prevent flooding as well as provide much-needed irrigation to arid regions of states like California and Arizona, which were experiencing an eight year long period of drought at the time. To this day it is one of the largest producers of hydroelectric power in the world." [ref.http://www.history.com/topics/hoover-dam 14/12/14]