Irrigation is an artificial application of water to agricultural land with the aim of supplying plants with the optimal soil moisture for desired growth and yields.  It is a science that extends beyond the bounds of simple delivery of water to plants as it encompasses achieving the appropriate balance of quantity, quality and timing of water supply as well as the stage of plant development and type of crop on the other.  Added to these is the aspect of weather variability and impacts of climate change which in one way or the other will have an impact on the irrigation enterprise.  From the outset, therefore, irrigation is aimed at maximizing yields and returns on invested resources.  Under certain circumstances, irrigation can be aimed at maximizing social benefits to communities depending on the sponsor of the intervention.

Irrigation engineering is the solution that delivers an irrigation enterprise by designing and causing to be built appropriate infrastructural interventions.  An engineered irrigation enterprise is that which has been designed to give rise to the optimum output or outcome by putting together a suitable combination of the various critical inputs for the development, operation and maintenance of the totality of the enterprise.



Irrigation is an activity undertaken by a farmer or a collection of farmers.  A farmer in this case can be a natural or legal person.  A legal person includes firms.  At the end of the day, a farmer wants to produce a crop that will have a marker and will maximize his income if he has an income objective or yields if he has a social objective such as food security.  However, at individual level, irrigation activities requiring engineering solution always has either an economic or financial objective.

At the macro-economic level, there has been increased focus on irrigation in Kenya due to its potential economic impacts.  Conservative estimates put the annual revenue generation potential of Kenya’s irrigation development promise at Kshs. 360 billion. This is money that will be generated at the farm gate, with no value addition and only considering medium, value crop production.  Considering a mix of high value crop production, value addition and the multiplier effect of the value chains connected or stimulated with this volume of production, the benefits of irrigation development to Kenya’s economy cannot be overemphasized. Finally, with its rural orientation, irrigation is a potent tool to trigger broad based economic growth in every corner of the republic across sectors.



In order to optimize the benefits of irrigation, there is need to start project conceptualization with a fairly clear end in mind. In this case the clear outcome will be either profit maximization for the farmer or yield maximization for social programs. This ultimate objective will then inform decisions all through the engineering and project development and operation process. In other words, all decisions from project conceptualization to its completion needs to focus on the penultimate goal of profit or yield maximization.

How then can this be made to be a running theme throughout the various stages of project preparation and implementation?

First, it is necessary to identify the key inputs that are required to ensure that an irrigation project is viable. These inputs include engineering aspects, agricultural aspects, social aspects, environmental aspects, economic aspects and financial aspects. The latter two can substitute for one another depending on whether the project is predominantly having a social or profit objective.


3.1 Engineering Aspects

This by far is the most straight forward of the critical inputs for an engineer. It involves evaluating the inputs from water resources specialists, agricultural specialists, surveyors, social impact specialists, environmental experts, economists, financial analysts and community development experts and using the information to come up with a solution best balances the key concerns or objectives of each of these aspects. While effectively addressing the penultimate goal of the project. It is, therefore, singularly important that an engineer presiding or overseeing an irrigation project possesses both the skill and experience that will enable him or her identify the key elements to address from each of these aspects that would ensure that first the project is viable, second that it is sustainable and lastly that it will deliver its penultimate objective. While viability is a fairly technical evaluation of the project, sustainability is entirely dependent on both viability and stakeholder’s acceptance of the engineered solution. Profitability, however, is dependent, on the viability, sustainability and capacity of the user or operator as the major factors.

In the Kenyan context, one of the most important considerations for technical viability is the availability, reliability and adequacy of the water resource. This is especially complicate due to incomplete hydrological data on many water resources, complete lack of data on most water resources, incomplete meteorological data or lack of such data in various catchment areas and unreliability of some data. In addition, the existence of water rights that are yet to be used or are partially in use, widespread unauthorized abstraction of water from various sources and lack of clear projection of future water demand presents a major challenge to accurate determination of the quantity and reliability of water supply. 

This aspect requires special focus and vigorous investigation in order to present a viable engineered solution.


3.2 Agricultural Aspects

Whereas the primary intervention in an irrigation enterprise is of an engineering nature, the eventual use is agricultural. The engineering solution is therefore aimed at solving an agricultural problem with the ultimate aim being either financial or economic. The engineer, therefore, needs to understand the agricultural enterprise that would be optimal for the irrigation project. In order to do this, the agricultural expert needs to develop an optimum agricultural development plan that matches the available soils to the most profitable crops that can be grown on the basis of market realities and projections. The markets explored may not be limited to the local markets but to international ones as well depending on infrastructure network, and profitability. The agricultural development plan will outline the crops to be grown, at what times, on what area and the crop water requirements associated with the various stages of crop growth.

Once the initial crop selection, cropping pattern, surface area for each crop and the crop water requirements is done, the engineer and the agricultural expert must engage in an iterative process that seeks to optimize a match between the area under each crop at any given time and place with the water available and the irrigation technology that would be viable from an engineering, agricultural and social perspective. The iterative process stops when an optimal solution balancing the three perspectives while addressing the penultimate goal of maximizing profit or yields is achieved within the boundaries of these aspects.

3.3 Social Aspects

One of the most ignored aspects of engineering design and implementation of projects has been the social considerations of development. This may have been because of the colonial bequeathed power imbalance between the main sponsor of public infrastructure development of that time and the citizens. The colonial government, just like the imperial governments before it, had overriding powers over the citizenry and therefore the decisions of government could not be questioned. Coupled with low population densities, mass ignorance of native populations or operators and the fact that the ultimate users of the infrastructure would be skilled government employees, the social aspects of infrastructural development could be safely ignored. Not anymore.

Social considerations has become one of the most important factors for integration into project design and implementation by engineers. Indeed, for irrigation projects it may as well be the determining factor between the success or failure of a technically sound engineering solution. Failure due to poor or lack of integration of social consideration in the project’s process can occur at any stage of the project cycle, right from site investigations. Social aspects include identification of the potential positive and negative impacts of a project on society at individual, household and community level. These impacts include those on relationships, dependencies, health, education, mortality, morbidity, poverty levels, settlements, take up of technology, livelihoods, etc. individuals, families and communities may support or sabotage a project depending on their own benefit – cost perceptions. Therefore, engineers need to ensure that societal concerns are received and effectively addressed within the engineered solutions.

Social considerations are even more central to the success of irrigation systems where communities are the end beneficiaries, users and operators of a project. The choice of irrigation technology, crops to be produced, lead time to optimal productivity, management structure and opportunities for value addition are strongly influenced by social factors. The dynamics around land acquisition, the cost and the lead time required to comprehensively deal with the same especially for water storage and common infrastructure need also be taken into consideration in project conceptualization and design. Finally, the desired economic impact of the project on the local communities will also have a strong influence on a project design since some technical choices for a private sector driven irrigation facility are different from those for a community driven irrigation facility. This also applies to livelihood issues such as livestock rearing, beekeeping ,fisheries, culture and other unique social norms that needs to be needs to be evaluated when providing holistic engineering solutions ,engineers should therefore take not that social considerations have become so important that they can put a halt  to projects with huge benefits to a countries economy and as such should not be treated with an altitude of satisfying the regulators .Instead, this aspect should be treated with the same  level of probity as the technical aspect of a project, especially because irrigation project require huge capital outlays which would be at risk if there factors are not given serious attention.


3.4 Environmental Aspects 

Environmental considerations have been mainstreamed into engineering projects for a considerably long time now. Apart from a few negative environmental impacts, irrigation projects tend to have strong positive environmental impacts that far outweigh the negative impacts. 

However the main issue here is how to package a project so that the irrigation measures against negative environmental impacts get incorporated into the project while enhancing the effectiveness of the positive impacts. This is a skill that the engineer presiding over the design, implementation and operation of an irrigation system needs to possess.

To prescribe solutions that that will remain relevant in the long term, climate change consideration also need to be part of an engineering solution. This may be in the form of mitigating the risk of likely adverse impacts of climate change on a project or leveraging on benefits that may accrue from the resilience enhancing impacts of a project.


3.5 Economic Aspects 

An irrigation project qualifies to have been “engineered” when it can meet the objectives for which it was conceived. Irrigation projects are either meant to respond to a social need or economic need. When irrigation is conceptualized to deliver some desired social outcome such as food security, food self- sufficiency, poverty alleviation or reduction, employment creation, among others, the economic viability of the enterprise is of critical importance to the long term sustainability. Indeed, if its long term sustainability cannot be guaranteed, then a solution has not been found to deliver the desired objective.

In review of the requirement, an engineering solution for an irrigation enterprise that has a social goal needs to be subjected to economic evaluation to determine its sustainability over the long term. For projects with potential for significantly high multiplier effect on other sectors of the economy, Economic Internal Rates of Return of as low as 8% maybe acceptable as a measure of economic viability. 

Measures of economic viability need to be supported by current market research that reflects realistic current prices and sound projections that that take into account the time frames within which maximum productivity can be achieved. Programs that may lead top early realization of maximum productivity may need to be included if they will have the effect of making the project more viable.


3.6 Financial Aspects

When an irrigation project has a profit objective, then its financial viability becomes the determining factor for its viability and sustainability. This is because the enterprise will definitely be abandoned if it does not deliver the desired objectives. For community based projects, household income becomes the key measure of financial viability of the project. If the total of the target beneficiaries will be sufficient to meet their requirements in the project situation, then the project will be viable. If the with project situation does not deliver the desired total income levels at the household, then there is risk of abandonment of the enterprise for some more rewarding investments. In the case of a company or a firm, any project that does not promise to deliver desirable returns will be abandoned at the point this is noted.

An engineer overseeing an irrigation project needs, therefore, to be alive to the financial demands of a project so that the solution he or she provides effectively responds and delivers this objectives. In order to do this, he needs to weave a logical thread through the various factors that have an influence on the project to inform the ultimate technical solution.


3.7 Conclusion 

Considering the aspect that an engineer needs to put into consideration in order to deliver an irrigation system that responds to user requirements, skills that exceed those imparted through the formal education system are required. Of paramount importance is the skill of coordinating professionals from various fields to provide outputs of good quality to contribute to the formulation of a sound engineering solution. The second critical skill is that of balancing and linking the various inputs into a logical frame that represents the cause-effect relationships of the various inputs on each other which ultimately leads to an optimal engineering solution. The last useful skill is that of presentation of the findings and solutions in a manner that connects all these aspects into one aggregated project that demonstrates that the solution will effectively deliver the users’ or sponsors’ objectives.

In this way, the benefits of an irrigation project is optimized for the user or sponsor.



In view of technological, social and legal advancements that have been made in Kenya, the engineer of today finds himself or herself in a situation, where every action or solution is open to question by an ever inquisitive public. For investments by the Government to achieve certain social objectives, the aspect of public participation and incorporation of the users’ views has become a constitutional demand. The consequences of poor, cosmetic or inappropriate public participation are indeed grave and, therefore, engineers will do well to build their capacities on this aspect of organizing and carrying out successful public participation as well as the skills to effectively interpret and use this input in providing user-friendly engineering solutions. Public input into engineering solutions should not be seen as interference in technical or professional matters by engineers, but as a critical input of a user so that the engineer may prescribe best fit for use as is their calling.

Investments by private individuals and firms are generally driven by a profit objective. The engineer of today needs to demonstrate a good grasp of the issues at play by appropriately advising such clients on the importance of these considerations since they are critical to the achievement of the clients’ objectives. The engineer of today is therefore, not just an engineer but a team leader.


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