Water security and rainwater harvesting at household level in a local municipality in South Africa: quantity calculations and supply implications
The current study seeks to estimate the total yearly volume of harvestable rainwater in Makana Local Municipality. The monthly rainfall patterns were analysed for the 2000-2020 period. The monthly rainfall did not vary with time for ten months in each year of the study period (p-values ranged from 0...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
University of Security Management in Košice
2023-12-01
|
| Series: | Košická bezpečnostná revue |
| Subjects: | |
| Online Access: | https://kbr.vsbm.sk/2023/n2/bavuma_ngowana_tandlich.pdf |
| Summary: | The current study seeks to estimate the total yearly volume of harvestable rainwater in Makana Local Municipality. The monthly rainfall patterns were analysed for the 2000-2020 period. The monthly rainfall did not vary with time for ten months in each year of the study period (p-values ranged from 0.1941 to 0.9518). The monthly rainfall increased with time in February (p-value = 0.0497) and decreased with time in April (p-value = 0.0235) between 2000 and 2020. The actual values of the monthly rainfall ranged from 0.0 to 218.4 mm. The completeness of the rainfall data ranged from 75 to 100 %, while its reliability was inside the interval between 91.7 and 98.4 %. The average total annual rainfall value was equal to 507.7 ± 127.8 mm and was also used in the calculation of the total amount of water which was available for harvesting in Makhanda. Based on the 12-month standard precipitation index values, there were 6 hydrological droughts in Makana during the study period. The probability of using alternative potable water source by the Makana population was estimated at 59.5 %, while there was a 28.8 % probability that a Makana household would have a RWH system installed. Using the 2020 rainwater harvesting system prices and involvement of the households’ occupants in the system installation, the total cost of providing each Makana household with a rainwater harvesting system was estimated at 44.493 million ZAR (1 USD = 15-19 ZAR). The total estimated volume of harvestable rainwater ranged from 17.2 to 48.6 m3, with the first-flush trap decreasing the volume by 25.3 %. If a 2500 litres tank was installed at each household in Makana, then the harvested rainwater could sustain an average-sized household for 4.5 and 37 days, based on the levels of consumption. |
|---|---|
| ISSN: | 1338-4880 1338-6956 |