The Gezira irrigation scheme, in Sudan, stretches out south of Khartoum between the Blue Nile and the While Nile Rivers. For more than 95 years since its establishment in 1925, the scheme has been a significant asset to Sudan’s economy. It is considered one of the oldest and largest schemes in the world being served by one management body using surface gravity irrigation from a single source. For many years, the system has performed with high efficiency and was considered a good model example, both locally and internationally. In the last few decades the scheme has deteriorated. The water productivity records show declining trends, while more water is being withdrawn from Sennar dam. Farmers are complaining about water shortages and some fields are not reached at all. Authorities state severe damages in the system’s infrastructure, with about 85% of the system’s hydraulic works being damaged. The performance of operation is well below the required efficiency. The sedimentation issue has always been present in the system, especially in the minor canals, but has been severe in recent years. As a result, farmers tend to interfere in the operation of the system, as they are not satisfied with the management authorities. Therefore, the scheme’s operation situations changed accordingly, shifting from the original design approach into new – often undesired – situations. There have been many studies carried in the Gezira Irrigation scheme, in order to understand the reasons behind this deterioration and find sustainable solutions. Starting from the causes of the sedimentation issue and maintenance works, generating new methods of calculating the crop water requirements using remote sensing, influence of farmers’ practices on field level, change of management and institutions throughout the history, and many others. Yet, there is no sensible change seen on the ground. The main objective of this thesis is contribute to the researches done in the Gezira scheme by providing an understanding of how the canalization system’s respond to various water demands strategies. In recent years, there has been a noticeable improvement in methods used to determine crop water requirements using remote sensing. Coping with these improvements, a main question rises, to what extent these remote sensing approaches could be implemented in large irrigation schemes, taking the Gezira scheme as a case study. Determining water requirements is one thing, delivering the water through the canal system could be something else. In order to answer the above question, we first need to analyze the system we are studying. This step was carried through analyzing the current, general, performance of the Gezira scheme and comparing it to the initial design characteristics of the scheme using the MASSCOTE framework (FAO). Using the outcomes of the MASSCOTE evaluation, the thesis proceeded by generating a computer model of the canalization system, taking a major and minor canal as a representation for the water distribution system, and testing different water demands scenarios. This step provided insights into the operation of the canalization system on the level of major and minor canals. It was found that, within the boundaries of our model, implementing new remote sensing methods is practicable, assuming water is readily available at the offtake of the major canal. This conclusion takes into consideration the lengths of the canals and their locations regarding the overall scheme and the carrying capacity of each canals.

This report represents the baseline study of the Project "Cotton Water", a collaboration between Solidaridad Asia, TU Delft and other participating instututions to improve the livelihood of cotton farmers in the Vidarbha and Marathwada regions of Maharashtra, India. This baseline study was divided in three main steps: a desktop study, where high resolution maps of precipitation, potential evaporation, soil type and landuse were used in conjunction with a smallholder socio-hydrological model to identify 'hotspots' where farmers' capital falls below poverty lines; a field survey, in which farmers were extensively questioned on their financial situation and farming practices as well as their perception of water scarcity and irrigation schemes; and a final synthesis where interventions are analysed with the smallholder socio-hydrological model and a psycho-social analysis of farmer behaviour is delivered alongside a mapping of current water productivity of cotton in the study area. The main results found are that the proposed water harvesting and recharge interventions increase and stabilize yields, and the overall effect on capital are moderate. Other factors that do not impact water availability including fertilizer and labour were found to have notable impacts and should be well understood to accurately improve farmers' situations. Financial aspects including cotton sale prices and loan interest rates had strong impacts on farmers' capital development as well, particularly with high interest rates punishing some farmers. An analysis of good- and poor-performing farmers demonstrated that irrigation in general and micro-irrigation did improve probability of good farmer performance as did increased yields. Older men also showed higher rates of profit, demonstrating that the impact of experience may increase profit margins, even if it necessarily doesn't increase likelihood to adopt interventions. What was found to increase probability of adopting irrigation and irrigation technology was low promotion exposure. It is hypothesized that increased promotion may influence many farmers negatively, fostering an attitude of despair rather than informing them of opportunity. The psycho-social evaluation also found that solutions that are reasonably expensive but not too costly have higher chances of being adopted.
Four main recommendations were made to help improve farmer welfare with respect to the scope specified. It was recommended to: limit promotion and to be more selective and positive with the message; focus on localized water storage interventions to increase farmers' access to water; regulate cotton prices through government intervention or contracts with clothing companies to decrease vulnerability to price changes; and improve access to loans from the government and reduce the role of money lenders who often are the ones charging the greatest interest rates.