A water reservoir can store rainwater for domestic use or for irrigating a vegetable garden. This manual describes how to make inexpensive cement storage tanks like straw or bamboo mat tank and
brick tanks. A small amount of cement is needed. The walls are reinforced with steel wire. The tank can be placed under a roof to collect rainwater or just beside a well with a pump to store irrigation water.
It is advisable to add a simple ground water recharge overflow pipe to store over capacity of water in the ground, ready to pump it up later.
Get the manual at: http://jacana.help/resources/water#maketank