Public-Private Partnerships (PPPs) are collaborative arrangements between government entities and private sector organizations for the financing, design, implementation, and/or operation of public infrastructure and services [6] . They are structured to leverage private sector efficiency, innovation, and capital while retaining public oversight to ensure that projects align with broader socio-economic objectives. PPP models vary, including Build-Operate-Transfer (BOT), Build-Own-Operate (BOO), Design-Build-Finance-Operate (DBFO), and lease or concession arrangements [7] . In Sub-Saharan Africa, PPPs have been applied in sectors such as transport, energy, and increasingly in water and irrigation projects, for example, the Bura Irrigation Scheme in Kenya, the Kpong Irrigation Scheme in Ghana, and the Bakolori Project in Nigeria [8] .

Despite their potential, PPP irrigation projects in the region often face significant challenges: weak regulatory and contractual frameworks, misaligned incentives between partners, inadequate feasibility studies, political interference, and insufficient financing [9] . In many cases, projects are initiated without clear risk-sharing arrangements, leading to cost overruns, delays, or underperformance.

In the Galana Kulalu Irrigation Project, the PPP arrangement involved the Government of Kenya, through the National Irrigation Authority (formerly the National Irrigation Board), and the private firm Green Arava from Israel [10] . The project was formulated as a PPP from the outset, with the government responsible for providing land, facilitating water rights, and financing initial infrastructure, while Green Arava was contracted to design, supply, and install irrigation systems, develop a 10,000-acre model farm, and provide technical training to Kenyan personnel. The expectation was that this model farm would serve as a proof of concept for scaling up to the full 1,000,000 acres. However, the PPP faced governance challenges, including delayed delivery of equipment, inadequate monitoring of contractor performance, and unclear enforcement of contractual milestones.

The Theory of Constraints (TOC), developed by [12] , posits that every project or system contains at least one constraint that limits its overall performance. In PPP irrigation projects like Galana Kulalu, such constraints frequently occur in financing, managerial coordination, land tenure resolution, and the adoption of appropriate technology. According to TOC, these bottlenecks must be systematically identified and addressed to improve project outcomes in terms of cost, time, and scope.

In this study, constraints such as insufficient financing, reported by 74% of respondents, emerged as primary barriers to success. TOC helps explain how erratic funding flows delayed the procurement of materials and machinery, leading to missed deadlines. Land conflicts, cited by over 65% of stakeholders, functioned as socio-political constraints that slowed stakeholder engagement and hindered access to project sites. These findings align with the TOC principle that “a chain is only as strong as its weakest link”, in this case, weak institutional coordination and resource allocation. By applying TOC, the study recommends “exploiting and elevating” these constraints through measures such as re-allocating budgets, strengthening inter-agency coordination, and integrating advanced irrigation technologies.

Principal-Agent Theory [13] examines the inefficiencies that arise when one party (the principal) delegates work to another (the agent) whose interests may not fully align. In PPPs, this misalignment can manifest as poor contract enforcement, inadequate risk sharing, and opportunistic behavior. In the Galana Kulalu case, the Kenyan government acted as the principal, while Green Arava functioned as the agent. Although the contract stipulated the development of a 10,000-acre model farm within a set timeframe, weak oversight mechanisms, such as advance payments without milestone verification, resulted in delays, scope drift, and under-delivery.

Empirical data from this study show that over 70% of respondents were dissatisfied with project governance, pointing to inadequate accountability structures. According to Principal-Agent Theory, such outcomes are common when contracts lack performance-based incentives and rigorous monitoring. For example, contractors may defer procurement or reduce quality assurance checks if they anticipate minimal repercussions, particularly in contexts with weak institutional capacity [14] . These dynamics help explain the observed project inefficiencies and underscore the need for better risk allocation, enforceable timelines, and transparent reporting mechanisms in PPP irrigation agreements.

Successful project planning is crucial in PPP irrigation projects, as it lays the foundation for execution. Research by [15] identified financial planning, managerial competence, and stakeholder engagement as key CSFs in construction projects. However, their study was not specific to irrigation projects, leaving a contextual gap. Similarly, [16] emphasized sustainability-oriented CSFs but did not consider large-scale PPP agricultural projects, limiting applicability to cases like Galana Kulalu.

In Sub-Saharan Africa, [17] found that poor financing structures, lack of expertise, and corruption significantly affect irrigation projects, leading to cost overruns and project delays. This is evident in Kenya, where expensive irrigation projects like Bura and Bakolori have struggled due to poor financial planning [18] . The Galana Kulalu project has faced similar issues, with budgetary constraints limiting execution and expansion. While studies highlight general planning challenges, there is limited research on how these factors specifically impact PPP irrigation projects, creating a gap that this study seeks to address.

The implementation phase determines whether planned strategies translate into successful outcomes. [19] identified management inefficiencies and poor risk allocation as major constraints in construction projects. While their study confirms the impact of governance on project execution, it lacks direct application to PPP irrigation projects.

Kenya’s Vision 2030 identified large-scale irrigation as a key driver of food security, yet the implementation of projects like Galana Kulalu has been plagued by governance issues, stakeholder conflicts, and technical inefficiencies [20] . [21] reported delays in Kenyan megaprojects due to unclear regulations, land disputes, and inadequate cost estimation. Similarly, [10] argued that large-scale agricultural projects often suffer from unrealistic expectations and mismanagement, leading to slow progress and inefficient resource utilization.

Despite its potential, the Galana Kulalu project has been marred by execution challenges, including contractor inefficiencies, misallocation of funds, and underutilization of available land. Previous studies have examined irrigation projects from a general perspective, but few have analyzed CSFs at both planning and implementation stages within PPP frameworks, particularly for large-scale projects [22] - [24] . This study fills that gap by providing a comprehensive evaluation of the CSFs influencing the execution of PPP irrigation initiatives in Kenya.

Existing literature on PPP projects has largely focused on regulatory frameworks, risk allocation, and governance structures in developed economies [15] - [18] . Studies on PPP infrastructure in Kenya have predominantly examined road projects [2] , with limited research on large-scale irrigation projects. Furthermore, while research on CSFs in construction projects exists, the unique challenges of PPP irrigation projects remain understudied.

No study has comprehensively analyzed how financial, managerial, and technological factors impact both the planning and execution stages of PPP irrigation projects like Galana Kulalu. This study bridges that gap by providing empirical insights into the challenges faced in large-scale irrigation projects and proposing strategies to enhance their success.

Figure 1 indicates that the execution of PPP irrigation projects, such as the Galana Kulalu Irrigation Engineering Project, is significantly influenced by CSFs that impact cost, time, and scope. These CSFs emerge at two key stages: planning and implementation, each presenting challenges that affect project execution and overall success.

At the planning stage, three major CSFs determine project feasibility. Insufficient project financing leads to funding gaps, delays, and inefficiencies in infrastructure development. The lack of expertise in irrigation engineering, financial planning, and project management results in poor decision-making, unrealistic scheduling, and increased maintenance costs. Additionally, land conflicts arising from disputes over ownership, compensation, and environmental concerns create legal and social obstacles that delay implementation.

In the implementation stage, further challenges arise, affecting operational efficiency. Poor management weakens coordination, leading to delays, cost overruns, and ineffective leadership. The lack of technology limits the adoption of modern irrigation systems, reducing efficiency and agricultural productivity. Moreover, stakeholder resistance from local communities, regulatory bodies, and private investors can disrupt execution due to misalignment of interests and conflicting priorities.

The success of PPP irrigation projects like Galana Kulalu is evaluated based on three primary performance indicators: cost, time, and scope. Cost efficiency is crucial to prevent financial overruns, while timely completion ensures that the project delivers expected benefits without delays. Additionally, scope adherence prevents inefficiencies arising from unplanned modifications.

By examining the effect of critical success factors in execution, this study aims to provide insights into overcoming financial, managerial, technological, and stakeholder-related challenges. Understanding these factors will help policymakers, project managers, and investors enhance project execution, ensuring that large-scale irrigation projects contribute effectively to food security, economic development, and sustainable agriculture in Kenya.

This study adopted a survey research design method of gathering information by administering a questionnaire to sampled individuals. The main feature of this survey research design was to describe specific characteristics of a large group of persons, objects, or institutions through questionnaires. The design was used due to its descriptive nature in order to assist in collecting data from members of the sample for estimating the population parameters used in the questionnaire.

A population refers to any group of institutions, people or objects that have common characteristics. The target population comprised 120 professionals directly involved in the Galana Kulalu Irrigation Project. These included engineers, project managers, procurement officers, field supervisors, and technical consultants. A stratified random sampling method was employed to ensure representation across these professional categories, recognizing their differentiated roles and perspectives in project execution. Using Cochran’s formula adjusted for finite populations, a sample size of 92 respondents was derived. The strata were proportionally allocated: 20% project engineers, 25% site supervisors, 15% procurement staff, 20% finance officers, and 20% policy/monitoring experts. Participants were randomly selected within these strata to reduce selection bias. The sample size was calculated from the study population of 120 using Cochran’s formula with an adjustment for finite populations to yield approximately 92 respondents.

The data collection instrument in this study was questionnaire, which was used due to its ability to reach respondents within a short time, its ability to give respondents adequate time to respond to the items, and it offers a sense of security (confidentiality) to the respondents. The questionnaire was divided into the main areas of investigation, except the first part, which captured the demographic characteristics of the respondents. The second part of the questionnaire focused on CSFs for PPP for large engineering irrigation projects in Galana Kulalu, Kenya. The questions used the Likert Scale of 1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree and 5 = strongly agree.

The first question asked the respondents, “To what extent do you agree that critical success factors at the planning stage contribute to success of the Galana Kulalu irrigation project?” The second question asked the respondents to how the indicators have influenced effect of CSFs at planning stage on success of Galana Kulalu irrigation project (based on a Likert Scale of 1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree and 5 = strongly agree) as indicated in Table 1 .

The third question asked the respondents to indicate “To what extent do you they agree that implementation-stage is critical success factors contribute to the success of the Galana Kulalu irrigation project?” based on Likert Scale of 1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree and 5 = strongly agree. The fourth question, presented in Table 2 , asked the respondents to indicate how the indicators have influenced effect of CSFs at implementation stage on success of Galana Kulalu irrigation project (based on a Likert Scale of 1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree and 5 = strongly agree.

Validity refers to the accuracy and meaningfulness of research findings, ensuring that the data accurately represent the study variables. This study assessed validity through content validity, ensuring that questionnaire items aligned with the research objectives. Reliability, on the other hand, measures the consistency of a research instrument over time. Cronbach’s alpha was used to assess reliability, with a threshold of 0.7 indicating a dependable questionnaire. The study computed Cronbach’s alpha for key constructs, including legal framework, risk sharing and allocation, and project governance, ensuring reliable measurement of these factors.

To enhance validity, the study integrated secondary data sources to triangulate findings. These included the Office of the Auditor General’s (2019) project audit report, documentation from the National Irrigation Authority (2020), and financial reports provided by the Ministry of Agriculture. These sources were used to cross-verify claims made by respondents, especially in regard to financing delays, procurement irregularities, and project performance outcomes. This triangulation helps offset the limitations of sole reliance on self-reported data and increases the robustness of the study’s conclusions.

To validate the data collection instrument, ten professionals from government agencies, private partners, and consultants in PPP projects reviewed the questionnaires. The content validity index was calculated using a relevance scale, and SPSS version 26 was used for analysis. A validity coefficient above 0.75 confirmed the instrument’s suitability for the study. The Cronbach alpha test was used to assess the internal consistency reliability of the constructs in this investigation, as shown in Table 3 .

The table shows four constructs: CSFs at Planning (α = 0.853), CSFs at Implementation (α = 0.809). According to conventional reliability benchmarks, values above 0.9 indicate excellent reliability, values between 0.8 and 0.9 suggest good reliability, and values between 0.7 and 0.8 indicate acceptable reliability. The results indicate that the study’s measurement instrument is statistically reliable, meaning that the survey or questionnaire items used for data collection effectively capture the intended constructs.

The information was gathered from specialists in government agencies such as the Public Private Partnership Unit (PPPU) at the Ministry of Agriculture's Water and Irrigation Department, as well as private partners and consultants involved in PPP projects. A total of 92 questionnaires were distributed, with 88 being returned as complete, indicating that they were all viable for processing. This translated to 95.7% percent response rate. This commendable response rate was made a reality after the study engaged research assistants to administer the questionnaires. This survey was therefore said to be successful.

The researcher was also interested in knowing the demographic information about the respondents that participated in the survey.

The researcher also inquired about the gender representation of the respondents and the results are presented in Figure 2 .

Figure 2 indicates that there are 61 male respondents and 28 female respondents, making males the majority group. In terms of percentages, males account for approximately 68.5% of the total sample, while females constitute 31.5%. This demonstrates a clear gender imbalance, with the number of male respondents more than double that of females.

The researcher inquired about the level of education of the respondents, and the results are presented in Figure 3 .

Figure 3 indicates that the study’s respondent profile shows that 50% hold a Diploma, making it the most common qualification. This suggests that most participants are mid-level professionals with technical expertise, crucial for executing large irrigation projects like Galana Kulalu. Individuals with Degrees (15.91%), Masters (14.77%), and PhDs (5.68%) likely represent managerial, strategic, and policy-making roles, contributing to high-level decision-making and project governance. Meanwhile, Certificate holders (13.64%) are likely entry-level staff involved in operational tasks.

This distribution highlights the study’s strength in capturing practical, field-based insights but indicates a limited representation of advanced-degree holders, who contribute to long-term planning, policy formulation, and innovation. While the workforce’s technical expertise is well-represented, fewer highly educated professionals may constrain the study’s exploration of strategic and theoretical factors.

The researcher also wanted to know the respondent’s position in the organization, and the results are presented in Figure 4 .

The study’s respondent distribution shows that casual employees make up 70.45%, while government officials (10.23%), private sector representatives (10.23%), and project managers (9.09%) form smaller portions. This suggests that the study predominantly captures operational perspectives, as casual workers handle daily project tasks. Their insights are valuable for identifying on-the-ground execution challenges but may lack depth in strategic planning, policy formulation, and governance issues.

The underrepresentation of government officials, private sector representatives, and project managers limits the study’s ability to fully explore high-level decision-making, institutional frameworks, and stakeholder coordination, which are essential for PPP project success. While practical execution challenges are well-documented, the study may offer a less comprehensive analysis of policy alignment and project oversight factors.

The researcher inquired about respondents’ duration of employment, and the results are presented in Figure 5 .

The study’s respondent distribution shows a workforce split between long-serving employees (29.55%) with over 10 years of experience and newer employees (less than five years, totaling 55.68%). Employees with 6 - 10 years of experience form the smallest group at 14.77%, suggesting a potential gap in mid-level experience.

The presence of long-serving employees provides deep institutional knowledge and insights into long-term project trends and CSFs. Conversely, the high proportion of newer employees may indicate recent hiring trends or workforce turnover, bringing fresh perspectives but lacking historical context. The low representation of midlevel employees may affect the balance between operational expertise and strategic oversight, potentially impacting project continuity and knowledge transfer within the Galana Kulalu Irrigation Project.

The researcher sought to inquire the respondents’ ratings on the success of PPP in Galana Kulalu irrigation project based on cost, timelines and scope. The data was collected using 5-point Likert Scale in order to capture the respondents’ feedback. When asked “Kindly indicate agree the extent to which Galana Kulalu PPP irrigation project has been a success.” The respondents survey is presented in Table 4 .

Table 4 presents respondents’ ratings on the overall success of the PPP in the Galana Kulalu Irrigation Project. Out of the 90 respondents, 43.2% strongly agreed and 23.9% agreed that the PPP has been successful, giving a combined positive rating of 67.1%. At face value, this suggests that most respondents believe the project has achieved significant milestones in line with its objectives. However, this finding contrasts with the widely held public perception, and independent audit reports, that the project has underperformed. This divergence may stem from differences in how “success” is defined. Many respondents were directly involved in project operations and may have based their assessments on partial achievements, such as completion of the 10,000-acre model farm, installation of some irrigation infrastructure, and delivery of training programs, rather than the full 1,000,000-acre target initially envisioned.

The study’s own findings identify lack of adequate financing as a major constraint to project implementation, a factor that has directly limited scope expansion and delayed broader benefits. Furthermore, no reliable data was obtained on the percentage of originally intended beneficiaries currently farming on irrigated land, an essential metric for objectively determining the project’s real impact. Without this information, claims of overall success should be interpreted as perceptions of operational progress among certain stakeholder groups, rather than definitive evidence of the project’s achievement of its intended scale and socio-economic outcomes. This interpretation aligns with the Critical Success Factors framework supporting this study, which emphasizes that successful delivery in PPP irrigation projects requires meeting scope, cost, and time objectives concurrently. While some CSFs, such as partial infrastructure delivery, may have been met, other equally critical elements, including sustained financing, broad beneficiary reach, and phased scaling, remain insufficiently addressed, limiting the project’s overall success.

The findings in Table 4 suggest that while the majority view PPP in Galana Kulalu as successful, a notable proportion of respondents remain either unsure or critical. This could indicate the presence of unresolved challenges. Respondents were asked to agree on some factors affecting success of PPP in Galana Kulalu irrigation project based on Likert Scale of 1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree and 5 = strongly agree. The results are summarized in Table 5 .

The evaluation of cost management, timely completion, and scope achievement as success factors for the Galana Kulalu Irrigation Project reveals strong agreement among respondents on their importance. Cost management emerged as the most critical factor, with 51.1% strongly agreeing and 36.4% agreeing that it significantly contributes to project success. The mean score of 4.28 emphasizes its priority, while the standard deviation (SD) of 0.98 indicates moderate variability in responses. This suggests that while most respondents agree on its significance, experiences with budgeting challenges vary across project roles.

Timely completion also ranked highly, with 50% strongly agreeing and 38.8% agreeing that meeting deadlines is crucial. The mean score of 4.09 and SD of 0.80 suggest broad consensus on the importance of scheduling efficiency. Lower variability in responses indicates that timely completion is recognized across all levels as essential for project success.

Scope achievement had a mean score of 3.98 and an SD of 0.79, slightly lower than the other factors. While still considered important, the lower mean suggests that meeting all project objectives poses some challenges. Cost management and timely completion emerge as top priorities, emphasizing the need for effective financial oversight and strict adherence to project schedules to ensure PPP success.

The researcher sought to inquire into whether CSFs at the planning stage influence the success of PPP in the Galana Kulalu irrigation project. The results are presented in Table 6 .

Table 6 summarizes respondents’ views on whether CSFs at the planning stage influence the success of PPPs in the Galana Kulalu irrigation project. Out of the 90 respondents, the majority, 46.6%, strongly agree that planning-stage CSFs significantly affect PPP success, while 20.5% agree, bringing the total positive responses to 67.1%. This suggests that most respondents recognize the importance of effective planning in achieving project success. A smaller percentage, 12.5%, remained neutral, indicating some uncertainty or lack of strong opinion on the matter. Meanwhile, 13.6% of respondents disagree and 6.8% strongly disagree, totaling 20.4% who do not believe planning-stage CSFs significantly impact success. These findings highlight the general consensus on the critical role of planning in PPP success. Respondents were asked to agree to an extent that CSFs at planning leads to success of Galana Kulalu irrigation based on Likert Scale of 1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree and 5 = strongly agree. The results are summarized in Table 7 .

Table 7 indicates that insufficient project financing was identified as the most critical factor, with 58.9% strongly agreeing and 35.6% agreeing on its significant impact. This resulted in a high mean score of 4.56 and a low SD of 0.60, indicating strong consensus. Lack of expertise also had a high impact, with 52.2% strongly agreeing and 34.4% agreeing, yielding a mean score of 4.34 and a slightly higher SD of 0.91, suggesting broader variation in opinions. Land conflicts followed closely, with 51.1% strongly agreeing and 34.4% agreeing, leading to a mean score of 4.28 and an SD of 0.99, reflecting slightly more diverse responses.

The overall mean of 4.12 confirms the importance of cost management, timely completion, and scope achievement in PPP success, while the low SD of 0.86 indicates strong agreement among respondents. These findings align with Okereke (2020) and Kamundia (2016), who identified poor planning, financial constraints, and political interference as key obstacles to irrigation projects in Africa. To enhance success, the study emphasizes better funding structures, capacity-building for technical expertise, and effective land conflict resolution mechanisms, ensuring financial sustainability and strategic planning in large-scale PPP irrigation projects like Galana Kulalu.

The identification of financing gaps and land ownership disputes as primary barriers aligns with the Theory of Constraints. These elements serve as systemic bottlenecks that disrupt the flow of resources and processes critical to project implementation. By focusing reform efforts on these constraints, such as increasing budget allocations and legal streamlining, project throughput can be significantly improved.

The researcher sought to know the influence of CSFs on success of PPP in Galana Kulalu irrigation projects. The result is presented in Table 8 .

Table 8 indicate that among the 88 respondents, the majority, 40.9%, strongly agree, and 33.0% agree, bringing the total proportion of positive responses to 73.9%. This indicates that most respondents acknowledge the crucial role of implementation-stage factors in determining the success of PPPs. A proportion of 6.8% of respondents remain neutral, suggesting some uncertainty or a lack of strong opinion on the matter. 13.6% disagree, and 5.6% strongly disagree, resulting in a total of 19.2% of respondents who do not believe that CSFs at the implementation stage significantly affect project success.

The high percentage of agreement (73.9%) indicates a strong agreement that the success of PPPs is significantly influenced by the quality of implementation. This aligns with the idea that even well-planned projects can fail if execution is poor, highlighting the need for efficient resource allocation, stakeholder coordination, and adherence to project timelines during implementation. The 6.8% neutrality suggests that a small fraction of respondents may perceive other stages, such as planning or monitoring and evaluation, as equally or more critical to success. Respondents were asked to indicate how the following indicators have influenced effect of CSFs at implementation stage on success of Galana Kulalu irrigation project based on Likert Scale of 1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree and 5 = strongly agree. The results are summarized in Table 9 .

Table 9 indicates that poor management emerged as the most critical challenge, with 58% strongly agreeing and 34.1% agreeing on its negative impact. A high mean score of 4.43 and a low standard deviation (SD) of 0.84 indicate strong consensus. Respondents emphasized the importance of effective leadership, project oversight, and managerial efficiency in ensuring smooth implementation.

Lack of technology was also seen as a significant factor, with 44.3% strongly agreeing and 37.5% agreeing on its impact. However, the mean score of 4.13 and the highest SD of 1.05 suggest greater variability in responses, indicating differing experiences with technological adoption. The findings align with [19] , who highlighted the role of modern technology in project success.

Stakeholder resistance was another major issue, with 43.2% strongly agreeing and 40.9% agreeing. The mean score of 4.14 and SD of 1.04 reflect moderate variability, suggesting that different stakeholders had varied experiences with opposition. Resistance stemmed from government agencies, private sector partners, and local communities, aligning with [10] , who highlighted stakeholder conflicts in Kenyan megaprojects.

The overall mean of 4.23 confirms strong agreement on the impact of CSFs at the implementation stage, while the SD of 0.98 reflects moderate variability. The study underscores the need for strong leadership, modern technology integration, and proactive stakeholder engagement to improve project execution in large-scale PPP irrigation projects like Galana Kulalu. Respondents indicated that machinery deliveries were delayed and scope reduced without penalties, a clear indication of weak principal-agent mechanisms. Principal-Agent Theory explains this as a product of asymmetric information and lack of enforceable performance metrics, where the private agent maximizes its utility at the expense of project goals.

The study revealed that insufficient financing was the most cited planning-stage constraint, mentioned by over 74% of respondents. This finding aligns with the broader literature. For instance, [2] reported that budget shortfalls were the leading cause of delays in Sub-Saharan Africa’s irrigation PPPs, specifically in Uganda and Zambia. Similarly, [7] emphasized that the financial viability of PPP projects depends on accurate upfront funding, particularly during the feasibility study and procurement stages. Land conflicts, identified by 65% of respondents, also mirror findings from [13] , where legal ambiguities on land ownership significantly delayed irrigation projects. This reinforces the idea that land security is a foundational determinant of infrastructure success, especially in arid and semi-arid regions. From a theoretical standpoint, these issues are well explained by the Theory of Constraints (TOC). The bottleneck created by erratic funding flows and unclear land tenure arrangements served as major constraints that stifled system throughput. Unless these constraints are elevated or removed, through legal reforms and financial planning PPPs, in agriculture will remain suboptimal.

Respondents ranked poor management (68%), lack of appropriate technology (59%), and stakeholder resistance (57%) as the most significant obstacles during the implementation phase. These findings resonate with the work of [25] , who argued that weak project governance structures in PPPs commonly lead to scope drift and inefficiency. In Galana Kulalu’s case, Green Arava’s failure to deliver promised infrastructure within the stipulated time and procurement bottlenecks mirror cases in the Bura

and Bakolori irrigation schemes (Nigeria), where weak performance monitoring led to misalignment between contractors and government entities. These problems are best interpreted through Principal-Agent Theory. The Kenyan government (principal) expected Green Arava (agent) to act in the project’s interest. However, the lack of enforceable performance metrics and poor oversight resulted in agent opportunism, evidenced by delayed deliveries, minimal stakeholder training, and underutilized land. As [26] suggests, such outcomes stem from misaligned incentives and information asymmetry between stakeholders. The absence of digital project management tools (e.g., ERP, BIM integration) and continued use of legacy irrigation technologies further reduced efficiency. According to [27] , incorporating digital tools improves scope accuracy by 17% - 25% in large-scale agricultural engineering projects.

This study examined the CSFs influencing the execution and performance of the Galana Kulalu Irrigation Project, a Public-Private Partnership (PPP) initiative in Kenya conceived under Vision 2030. The findings indicate that insufficient project financing, lack of technical expertise, and land conflicts significantly constrained project planning, while poor management, limited technology adoption, and stakeholder resistance hindered implementation. nAlthough the project was formulated as a PPP from the outset, bringing together the Government of Kenya, through the National Irrigation Authority, and the private contractor Green Arava, the arrangement did not follow the typical PPP funding structure. The government provided the bulk of the financing, land, and enabling infrastructure, while the private partner’s role was limited to supplying irrigation technology, developing the 10,000-acre model farm, and offering technical training. The private partner did not provide capital investment for large-scale implementation, meaning that critical risks and financial burdens remained primarily with the public sector.

This financing arrangement partly explains why insufficient funding emerged as a major constraint despite the PPP label, raising questions about whether the project’s structure met the standard definition of a risk- and investment-sharing partnership. The results highlight the importance of structuring PPP irrigation projects to ensure balanced contributions from both parties, financially, technically, and operationally. Addressing the identified CSFs through effective financial planning, robust contractual arrangements, strong leadership, modern technology adoption, and proactive stakeholder engagement can improve cost efficiency, timely completion, and scope adherence. The study recommends that future PPP irrigation projects incorporate clear, enforceable risk-sharing agreements, independent technical vetting, and equitable funding commitments from both public and private partners to enhance sustainability and developmental impact.

Given that the primary data source comprised self-administered questionnaires, the study acknowledges the inherent risk of response bias, where respondents may offer socially acceptable answers rather than factual accounts. This may particularly affect questions regarding project management efficacy and stakeholder satisfaction. To mitigate this, the questionnaire was pre-tested to enhance clarity and neutrality in question phrasing, and anonymity was guaranteed to reduce social desirability bias. Furthermore, the analysis emphasized cross-variable correlations to identify inconsistencies or inflated responses.

While triangulation and stratified random sampling were employed to improve reliability, some limitations persist. Self-reported data remains susceptible to bias, and complete documentation from private contractors was unavailable, limiting full triangulation. Although stratification helped reduce sampling bias, there is a possibility of residual selection bias due to potential non-responses or inaccurate contact lists from institutional databases.