Water Harvesting Techniques

Classification Rainwater Harvesting

Water harvesting techniques may be classified into two major types, based on the size of the catchment Figure 6 micro-catchment systems and macro-catchment systems Oweis et al., 2001 . Surface runoff in micro-catchment systems is collected from small catchments usually less than 1000 m2 and applied to an adjacent agricultural area, where it is stored in the root zone and used directly by plants. The target area may be planted with trees, bushes, or annual crops. The farmer has control, within...

Drought Policy In South Africa

South Africa has a long history of living with drought. A drought during the early 1930s that coincided with the great depression made a deep impression on many policy makers. Significant droughts also occurred during the 1960s, 1980s, and early 1990s. Despite this familiarity with drought, policy makers still struggle to quantify it and to develop a stable policy framework. Drought policy falls at the interface among the numerous definitions of drought that require some quantification of...

Palmer Drought Severity Index PDSI and Palmer Hydrologic Drought Index PHDI

The PDSI, based on the Palmer Drought Model Palmer, 1965 , has been one of the most commonly used drought indicators in the United States. One reason for its popularity is that its development in 1965 preceded other indices and resulted in its widespread use and wide-ranging application. The PDSI is derived from a moisture balance model, using historic records of precipitation, temperature, and the local available water capacity of the soil. The PHDI uses a modification of the PDSI to assess...