Making Rainwater Harvesting a Key Solution for Water Management: The Universality of the Kilimanjaro Concept

Abstract

Rainwater is conventionally perceived as an alternative drinking water source, mostly needed to meet water demand under particular circumstances, including under semi-arid conditions and on small islands. More recently, rainwater has been identified as a potential source of clean drinking water in cases where groundwater sources contain high concentrations of toxic geogenic contaminants. Specifically, this approach motivated the introduction of the Kilimanjaro Concept (KC) to supply fluoride-free water to the population of the East African Rift Valley (EARV). Clean harvested rainwater can either be used directly as a source of drinking water or blended with polluted natural water to meet drinking water guidelines. Current efforts towards the implementation of the KC in the EARV are demonstrating that harvesting rainwater is a potential universal solution to cover ever-increasing water demands while limiting adverse environmental impacts such as groundwater depletion and flooding. Indeed, all surface and subsurface water resources are replenished by precipitation (dew, hail, rain, and snow), with rainfall being the main source and major component of the hydrological cycle. Thus, rainwater harvesting systems entailing carefully harvesting, storing, and transporting rainwater are suitable solutions for water supply as long as rain falls on earth. Besides its direct use, rainwater can be infiltrating into the subsurface when and where it falls, thereby increasing aquifer recharge while minimizing soil erosion and limiting floods. The present paper presents an extension of the original KC by incorporating Chinese experience to demonstrate the universal applicability of the KC for water management, including the provision of clean water for decentralized communities.

Potential Water Harvesting Sites Identification Using Spatial Multi-Criteria Evaluation in Maysan Province, Iraq

“…The earth has an abundance of water, but unfortunately, only a small percentage (less than 1 percent) is even usable by humans [1], and more than 99 percent is unusable in the oceans, soils, icecaps, and floating in the atmosphere. Climate change, population growth, and rapid industrialization are regarded as the three main global drivers increasing stresses on safe water supply worldwide [2]. Stress on freshwater resources due to rising demand is already leading to water scarcity in many places, especially in arid and semi-arid areas that face a water scarcity problem in terms of domestic use and agriculture.…”

Metallic Iron for Environmental Remediation: Starting an Overdue Progress in Knowledge

“…Fe 0 -based systems present unprecedented opportunities for wastewater treatment and safe drinking water provision especially in low-income countries, including those in Africa (Table 4) [144,157,[191][192][193][194][195][196][197][198][199][200][201]. In fact, the use of Fe 0 -based systems (e.g., the Bishof Process) for clean water provision has a long history dating back to the 19 th century [13,14,202].…”

“…The history of Fe 0 -based drinking water treatment systems is discussed in detail in earlier review papers [17,18,122]. Recently, our research group has proposed the integration of Fe 0 -based systems in rainwater harvesting systems as a low-cost technology for decentralized drinking water provision, in what is known as the Kilimanjaro Concept [192][193][194]. Table 4.…”

“…Natural water equilibrates with iron nails and flocs are filtered on gravel [191] 6. Decentralized rainwater harvesting systems for drinking provision Fe 0 filters are efficient to remediate expected contaminants [192][193][194] B: Wastewater treatment systems:…”

Integrated Water Resource Management: Rethinking the Contribution of Rainwater Harvesting

“…With such an approach, enhancing groundwater recharge and reducing aquatic pollution start at household level, with each individual world citizen being involved, including those living in the slums of Durban (South Africa) and even in the best squares of Peking (China). Given the timeframe of only 10 years (2021-2030), progress towards fulfilling the two named SDGs requires that existing knowledge is effectively translated into practical solutions within this short time period [2][3][4].…”