WATER HARVESTING SECTION

INTRODUCTION

Rain water harvesting is the process of accumulating and storing rainwater for use before it reaches the acquifer. Household rainfall catchment systems are appropriate in areas with an average rainfall greater than 200mm per year and no other accessible water resource (Skinner and Cotton, 1992). This process is implemented by construction of water tanks using locally available materials such as stones and rough sand. The Department of Soil and Water conservation has designed a simple manual for construction with simple steps to be followed and they are successful.

OBJECTIVEThe objective of building roof water tank is to promote agricultural production especially vegetables at home gardens for consumption and income generation for the benefit of the family, moreover to increase quantity of water for livestock purposes. The idea of roof water harvesting came around early 1990s when there was severe drought in Southern parts of the country. Roof water harvesting was the viable means to shorten distances travelled by women, especially in rural areas to search for water to water their home gardens.
TYPES OF WATER TANKS

There are two types of water harvesting tanks

• Roof water tank: water is collected from a corrugated iron roofed house and gets into a tank through gutters. A tank is constructed 1m away from the house. The roof water tank is mainly for subsistence farming.
• Spring tank: water is collected from a reliable spring/stream and a small catch/collection box as it is called, is constructed and HDPE pipes are used to enable water to get into the tank. The spring tank is mainly for commercial farming.

FUNCTIONS OF WATER HARVESTING SECTION

• Carry out feasibility study for viability of appropriate water harvesting methods
• Survey and design water tank in order to determine its capacity
• Supervise construction of a water tank