Abstract
Food and water are at the heart of sustainable development. Roof-harvested rainwater kept in rainwater storage systems (RSS) and used in household agriculture (HA) has the potential to increase yields and supplement household nutrition. Combined systems may contribute to at least eight of the United Nations’ 17 Sustainable Development Goals (SDGs). In this paper, a daily analysis tool, ERain, is used to assess what area of vegetables can be reliably irrigated by roof-harvested rainwater. A socio-economic context is built around an orphanage in the semi-humid region of Nakuru, Kenya. Comparisons are made with the semi-arid region of East Pokot. A 225 kL closed masonry tank and a 1 ML open reservoir with an additional 8 kL/day of recycled water entering are analyzed for various roof sizes. The 225 kL RSS connected to 1000 m2 of roof and irrigating 1000 m2 could increase yields from 1850 to 4200 kg/year in Nakuru. If evaporation was controlled, the 1 mL RSS and recycled water system could support 4000 m2 of land, yielding nearly 20,000 kg/year, which is enough to meet the WHO recommended vegetable dietary requirements of the orphanage. A combination of crops, some for consumption and some for sale, could be grown.
Highlights
The Garden of Eden, or Paradise, has long captured the heart and imagination
We focus on the 1000 kL reservoir, which is used to irrigate a 240 m2 of greenhouse crops
The NASA rainfall data seemed problematic as on closer analysis, it was found that it reported days of rain per year, while the CHIRPS data reported only 57 days, which is much less than the WMO value of 132 days/year [44] for Nakuru
Summary
The Garden of Eden, or Paradise, has long captured the heart and imagination. Many aspire to live in, and search for, such a paradise lost, often for more ascetic reasons. Yields from between zero (crop failure) to over 20 kg of vegetables per m2 have been reported for small-scale agriculture [2]. This is important in developing countries, where many people lack nutrition. The fact is that more than enough food is produced worldwide to feed everyone [3] It is unevenly distributed, leading to a world where 1 in 9 people remain hungry and 1 in 4 children are stunted [4], while 1.9 billion adults are overweight [5]. Household agriculture (HA) or home gardening at a small scale bypasses the distribution issue and has the potential to significantly contribute to household nutrition, that of women and children
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