Agriculture, fishing and forestry contribute more than $155 billion a year to the GDP of Australia. There are over 135,997 farms in the continent covering more than 61% of its landmass. Australia is the driest inhabitant continent. As more than 2/3rd of the land is covered by agriculture, fishing and forestry, collecting rain water is essential to cope up with the need of water. Farmers cannot pour the rain water down to drain. Therefore, it is extremely important for every farm and some industries to have dams and water reservoirs.