Rainwater harvesting for irrigation in semi-arid regions of Kenya

State-led irrigation development in Kenya

Kenya has pledged to build a hundred megadams in the next five years. This pledge was repeated at the UN Water Conference, 2023. Source: Magnum, 2023

Even though the significant proportion of freshwater in Kenya is used for agriculture, most smallholder farmers do not have access to irrigation services. The majority of smallholder farms in Kenya are rainfed and predominantly situated in arid and semi-arid lands (ASALs), where agro-pastoralism is common, involving both crop cultivation and livestock keeping (Recha et al., 2018). Smallholder agricultural practices in Kenya are characterized by farm sizes ranging from 0.2 to 3 hectares, with a crop composition divided between maize and a variety of other crops such as sorghum, millet, cassava, potatoes, beans, and horticultural produce including vegetables and fruits (Rao et al., 2015). 

Despite the lack of access to irrigation, smallholder farms account for 78 percent of total agricultural production in Kenya (Birch, 2018). ASAL-based smallholder farmers specifically face significant challenges in production stemming from meteorological droughts, intraseasonal dry spells, and high evapotranspiration rates, exacerbated by climate change impacts (Abrams, 2018; Rockstrom et al., 2003). Much of smallholder agricultural production is limited to household consumption, and farmers often have to depend on additional sources of income for their livelihoods (Recha et al, 2018). 

Public irrigation schemes in average realize only 40 per cent of the target production levels compared to private operated irrigation schemes, and many cease to function or operate below capacity as soon as the financing agencies and development partners end their funding. For example, the average performance in the Ahero, West Kano and Bunyala irrigation schemes was 48%, 49% and 56%, respectively, with the Bunyala irrigation scheme being the highest performing rice irrigation scheme in western Kenya (Muema et al, 2018). Low levels of functionality have also been attributed to corruption and vested interests, the persistence of Western models of development, and a purely top-down technically oriented approach. Moreover, the damming of rivers has contributed to a myriad of environmental problems, including sedimentation, ecological damage, and over-abstraction of water, which have contributed to the dysfunctionality of many state-led irrigation schemes (Bjornlund et al, 2020). 

Farmer-led irrigation development in Kenya

As public irrigation schemes have run into issues in Kenya, farmer-led irrigation development (FLID) has expanded rapidly. FLID is characterized as a process whereby farmers plan, pay for and implement irrigation systems with little to no external support (Woodhouse et al, 2017). There are generally two typologies of FLID in Kenya: i) individual (private) irrigation for high-value crops, and ii) small-scale community-based irrigation schemes (Mati, 2023, Muturi et al, 2019, Giordano et al, 2012). FLID has been recognized as a driving force behind irrigation expansion and agricultural intensification in Kenya (Mati, 2023).

However, there are some limitations to the expansion of FLID in Kenya. In terms of geographical limitations, most FLID systems are bounded to the areas around water bodies such as lakes or rivers. This means that farmers located further away from water bodies, in more arid areas, cannot benefit from them. Significantly increasing groundwater abstraction for irrigation in areas far away from water bodies is not a viable solution for smallholder farmers either, as there is a lack of useable groundwater resources in many parts of Kenya, and construction and abstraction costs are often unaffordable to the average smallholder farmer (Olago, 2018). 

Moreover, even if farmer-led irrigation systems could be expanded further, the existing problem of over-abstraction of water bodies would be further exacerbated. Indeed, as increasing numbers of farmers are investing in irrigation technologies (Hornum and Bolwig, 2021; Muturi et al, 2019), many water bodies that were once perennial are now running dry in some parts of the year (Ngigi, 2008; Mdee and Harrison, 2017). This could make the livelihoods of farmers depending on downstream flows more insecure (Rockstrom et al, 2003; Giordano et al, 2021). Across sub-Saharan Africa, FLID is often associated with intensive water use and low water productivity due to prevalent methods of unregulated water extraction and application (Woodhouse et al, 2017).

Potential of rainwater harvesting for irrigation

In response to the challenges posed by state-led irrigation development in terms of the financial and environmental costs of big dams, as well as the issues with FLID due to inefficient water use and high levels of water abstraction, practitioners in the field of agricultural development in Kenya have called for the adoption of rainwater harvesting for irrigation (RWHI) systems. RWHI systems have several benefits over both state-led and farmer-led irrigation development. Unlike large dams, RWHI systems in Kenya tend to be constructed at the household or community level, minimizing environmental consequences and impact on ecosystems. They also tend to be associated with irrigation technologies that increase water productivity, such as drip lines, rather than inefficient methods of irrigation, such as flooding. 

Moreover, RWHI systems can be built in areas inaccessible to water bodies, as they harvest and store the rainwater where it falls. Another major advantage of RWHI is that it allows farmers to grow more profitable crops that require more water or use the extra water to increase yields in drier seasons. RWHI can also reduce flooding, recharge groundwater, increase water supplies to crops when they are at sensitive growth stages, and save conventional water sources, making it a crucial component of regional water management (Yosef and Asmamaw, 2015; Enfors and Gordon, 2008; Snelder et al, 2018; Oguge and Oremo, 2018; Bouma et al, 2012; Rockstrom et al, 2003). Other positive outcomes of RWHI systems include improving farmers’ resilience to climate change and soil fertility (Karpouzoglou and Barron, 2014). 

In recent decades, as Kenya's population grew and urbanization increased, there was a renewed interest in rainwater harvesting as a solution to water scarcity and unreliable water supply. Efforts to promote rainwater harvesting in Kenya have included the construction of rooftop catchment systems, the development of small-scale reservoirs and dams, and the implementation of community-based rainwater harvesting projects. These initiatives aim to provide communities with a reliable and sustainable water source, especially in arid and semi-arid regions of the country (Odhiambo et al, 2021; Mugo, 2019; Sunman, 2017; Songok, 2018).

Challenges to scaling of RWHI systems

Given the potential of RWHI, actors including NGOs, donors, and government agencies, have carried out attempts to scale up RWHI systems across Kenya over the last fifty years. RWHI was formally presented as a possible solution to food insecurity in Kenya during the droughts of the 1970s and 1980s, where schemes used a mix of subsidies and incentives (such as the food-for-work programs) to construct RWHI systems (Sunman, 2017). Currency, various NGOs, government agencies, and international organizations have been involved in promoting rainwater harvesting practices to address water challenges, particularly in rural areas.

Due to efforts by both government agencies and development organizations, the level of RWHI adoption has increased in Kenya. However, several factors limit its potential to scale. Research conducted by Matiti (2018) revealed that numerous RWHI systems in Kenya are not performing to anticipated standards. This study highlighted that RWHI systems are often unreliable and technically inefficient. Moreover, a report by Chamwada (2019) pointed out that a variety of farm ponds and reservoirs, constructed under the government household irrigation and water storage program, fail to fill to their full capacity, even after extended rainy seasons. 

It was also observed that many smallholder farm ponds experience substantial water losses through seepage and evaporation, leading to the ponds drying up before the conclusion of the growing season (Wachira, 2013). Further investigation by Matiti (2018) discovered that a significant number of reservoirs have diminished capacity due to heavy siltation, while others are entirely damaged by water overtopping their banks, resulting in collapse. Consequently, the impact of these systems on farming has been minimal, with farmers experiencing prolonged periods to recoup their investment. In some instances, investments have been entirely lost due to RWHI system failure (Kiggundu et al, 2018).

Explaining lack of adoption

This research adds to the literature on RWHI adoption and scaling in Kenya, which until now has focused mainly on hydro-geological or techno-managerial aspects of the RWHI system adoption (Getnet and MacAlister, 2012). The focus on socio-economic factors at the household level has led to a significant body of literature that investigates factors such as farmers' motivations, economic incentives, and resource availability. These studies have shed light on the individual-level barriers and facilitators of RWHI adoption, offering valuable insights into localized adoption patterns. 

Similarly, technical investigations have analyzed the efficacy of specific rainwater harvesting technologies and their compatibility with local agroecological conditions. While more qualitative studies do exist, they limit their analysis to the challenges witnessed in project-based initiatives, such as the lack of technical expertise, participatory planning, and effective operations and maintenance. They often conclude with generic recommendations such as improving capacity building, extending credit opportunities or adopting a more inclusive planning approach, or argue that the main impediment to RWHI adoption is the risk-averse attitude of farmers and see the solution to be behavioural change. Such studies usually do not go beyond analysis of external interventions and therefore exclude research on farmer-led adoption of RWHI systems. 

Close examination of infrastructure, energy requirements, transportation, market prices, type of markets, middle-men, storage, and many other factors affecting access to agricultural markets has been neglected in literature that argues for the promotion of RWH technologies. Most studies fail to consider the broader systemic context. There is also almost no analysis on how conditions in agricultural markets can affect adoption– a huge oversight if RWHI technology is to be used for growing commercial crops (Bouma et al, 2012).

Concepts guiding research on RWHI

To understand how policy and governance can create a more enabling environment for the adoption and scaling of RWHI, this research leverages the theories and concepts of the technological innovation systems, sustainability transitions, the livelihoods perspective, as well as related analytical frameworks. 

The technological innovation systems concept demonstrates that for scaling of RWHI from the niche to the regime, an innovation system around RWHI needs to develop. This innovation system encompasses actors, interactions, institutions, infrastructures, and technologies that together fulfil several functions of an innovation system that decrease the costs and maximize the benefits of adoption. The theory of sustainability transitions demonstrates the process by which an innovation can catalyse systemic changes in agrifood systems. When the innovation becomes embedded in the dominant regime, it begins reconfiguring socio-technical systems and promulgating more desirable social and environmental outcomes. 

The livelihoods perspective illustrates how a change in the prevalent vulnerability context and in long-term structures and processes give rise to new livelihood opportunities. For an innovation to be adopted as part of a new livelihood opportunity, it needs to increase a household’s access to natural, social, political, physical or human capital compared to other types of potential livelihood strategies available to a household. If this is the case, the innovation begins to scale and moves from the protected niche space of innovation development and enters the regime, where it can begin to influence dynamics in dominant socio-technical systems.

​​The findings reveal that policy and governance mechanisms to support RWHI adoption must consider a range of factors beyond the farm level. While existing water and agricultural policy and governance structures provide some support for RWHI adoption, they are predominantly focused on delivering inputs rather than fostering an enabling environment. Fostering an enabling environment involves the development of actor-networks around RWHI technologies that can respond to political dynamics, environmental and climatic conditions, economic structures, and socio-cultural institutions. A shift in focus is advocated that targets not just farmers but also other key actors such as Community-Based Organizations (CBOs), Non-Governmental Organizations (NGOs), the private sector, financial institutions, and the public sector. By doing so, an enabling environment for RWHI adoption and scaling can be developed, thereby contributing to the sustainability of smallholder irrigation practices in Kenya.