Kenya’s main irrigated crops are rice, maize, sugarcane, vegetables, bananas, citrus, coffee, tea, cotton and flowers, some of which require large-scale production for economies of scale to be realized.

 

Irrigation infrastructure has been funded in targeted areas in a bid to improve food production and rural economies. Currently, the Kenyan government has been running the operations of the major five public irrigation schemes (Figure 2) in different parts of the country through the National Irrigation Board (NIB). Generally, irrigation activities demands costly continuous operations in terms of supply of water and adequate maintenance of the water distribution and drainage channels. The government, the private sector, and development partners have funded most of the irrigation structures since it is difficult for smallholders themselves to build such structures (PMU-Kenya, 2004). World Bank (2007) indicated that irrigation projects consume many scarce resources through both recurrent and development expenditure and adversely affect developing countries, whose capacity to set up irrigation infrastructure is limited. Ngigi (2002) and Kibe (2007) revealed that, the development of irrigation despite the high costs involved is one of the largest potential for addressing the challenge of the declining agricultural productivity with an up surging population in Kenya. In addition, availability of water also plays a vital role on the performance of an irrigation scheme and indirectly influences the cost of the project. Furthermore Saleth et al. (2003); Hussain and Wijerathna (2004); Hussain et al. (2006), and Inocencio et al. (2007) concluded that, those irrigation schemes located in areas with more water available have a tendency of being smaller in size and  it  reduces  poverty both directly and indirectly. Direct impacts are realized through labour and land augmentation effect that ultimately translates to improved performance, employment, income and consumption, while the indirect impact is realized through enhanced local economy and improved welfare at macro level. On the contrary, Fan et al. (2000) and Jin et al. (2002) revealed a negative and/or weak relationship between irrigation and agricultural productivity. This leads to a negative or no impact on food security, household income and poverty reduction at large; hence the direct effect of irrigation could be undermined by other factors, which could have been observed at scheme level. Fan et al. (2000), Gomanee et al. (2003), and Mosley et al. (2004) found out that, higher government expenditure on agriculture, housing and amenities (water, sanitation and social security) had a negative and statistically significant impact on poverty. This is mainly by shifting the distribution of income in a pro-poor direction, since the level of aggregate income was held constant in their regressions.

 

Recently, emphasis has been on the importance of sustaining and improving the performance of existing irrigation schemes in parallel with area expansion and development of new irrigation (World Bank, 2006). In Kenya, like in many other African countries, irrigation expansion has been hindered by poor performance of the existing public irrigation schemes (Ngigi, 2002; Thairu, 2010). In addition, the performance of public irrigation scheme  is  way  off  the  mark  realizing  only  40% of the target production levels and 28% of the expected revenues (Karina and Mwaniki, 2011). Paradoxically, there are successful irrigation undertakings especially among the private commercial large-scale agricultural irrigated farms such as Dalamare, Delmonte, Kakuzi, etc. Given the intensive investment, the already existing public irrigation schemes in the country should be operating efficiently and effectively so as to meet the rising food demands.  However, it is not clear what factors play key role in the performance of public irrigation schemes in Kenya. Against this backdrop, this study seeks to establish the factors that influence performance of public irrigation schemes in order to shed some light on the areas requiring policy interventions. Furthermore, it would complement the debate on public irrigation scheme performance, and provide a basis for reformulation of strategies that are geared towards the country’s self-sufficiency in food production and food security.

 

Irrigation performance is the level at which resources such as water, land, and labour can be effectively utilized for the production of maximum output levels. In addition, irrigation performance assessment is the regular observation of irrigation performance parameters with the objective of acquiring important information on the use of resources within an irrigation scheme, and allows irrigation managers to make well informed decisions in terms of resource management (Bos et al., 2005; Khan et al., 2009; Mati, 2011; Valipour, 2014). Irrigation performance assessment can be used to satisfy different set objectives on different irrigation schemes but the procedure will vary depending on the system and purpose of assessment. Despite the fact that there is still no one standard way of measuring irrigation performance, most analysts suggest at least two basic domains for the purpose of irrigation or water delivery and agricultural productivity. While the former is associated with the immediate service output and determined most frequently through the performance criteria of adequacy, equity and reliability of water supplied, the latter is considered more outcome-based and can be judged against such parameters as farmers’ crop yields, cropping intensities and most recently water productivity. Other studies suggest that such a limited set of indicators should also include measures determining the maintenance status of irrigation infrastructure as well as more user-based socio-economic impact measures (Murray-Rust and Snellen, 1993; Bos et al., 2005). Molden et al. (2010) pointed out that for an increase in irrigation scheme performance, it will require strategies that are based on existing biophysical and socio-economic factors. Frequent evaluation of irrigated areas have become more important in diagnosing and improving the performance of irrigation schemes in order to achieve optimal productivity in the context of increasing food demand, open global markets and competition for limited freshwater resources (Burt et al., 1997;  Molden  et  al.   1998; Clemmens, 2006). Such assessments should analyze the productive and hydrological impacts of internal irrigation processes to assist agents involved in crop production, water management and agricultural policy to improve the performance of irrigated schemes (Perry et al., 2009; Molden et al., 2010).

 

The categories of the determinants of  irrigation performance has been described by Malano and Burton (2001), Molden et al. (1998) in Molden et al. (2010) and it includes those factors such as land, labour, water, cost of scheme operation and maintenance as well as the value of production that analyze the inputs into and outputs from irrigation scheme. They further developed a set of irrigation performance indicators for describing performance at scheme level that includes output per cropped area, output per unit command area, output per unit irrigation supply, output per unit water consumed, achieved production factor, and potential production factor among others. In addition, Ntsonto (2005) concluded that there is need to include financial and environmental indicators since they concentrate on the costs and returns, in monetary value and they include cost recovery ratio; maintenance cost to revenue ratio, total cost of management, operation and maintenance per irrigation scheme and revenue collection performance. While on the other hand, the environmental indicators concentrate on sustainability of irrigation scheme performance, pollution of both land and water as well as the effects of irrigation on the surroundings (Greaves, 2007; Yokwe, 2009).