Farmers in Tipitapa, Nicaragua, face arid farming conditions during the annual extended dry season due to the lack of reliable water supplies and irrigation technologies to sufficiently water crops. With limited well-water supply, the residents can only produce for sustenance. Smallholder farmers typically use flood-irrigation to water their fields since affordable irrigation technologies are limited. However, in the warm, dry climate and with fields characterized by clay soil, this leads to excessive amounts of wasted water due to evaporation and runoff.
In partnership with Winds of Change, a Toronto-based foundation, students carried out two projects aimed to design a more water-efficient irrigation system that could be tailored to different plant needs in order to increase crop yield, which also can easily be operated and maintained by the residents.
The first group looked at different irrigation processes, and drip irrigation network showed the most potential in rural applications. These constitutes multiple rows of tubing laid across the field. After extensive prototyping and in-soil testing, the final design was an efficient, easy-to-make emitter. Tubing is punctured at set intervals, threaded through reclaimed bottles, and buried shallowly in the soil. This design minimises evaporation loss and the half-bottle creates a cavity for the water to be stored. The plants then absorb the water at a slow rate over the day. This method merges several benefits of different traditional irrigation techniques, with added advantages of lower cost and labour.
The second group studied different irrigation emitter technologies and developed a software tool to affordably plan, design, and optimize these drip irrigation systems, maximize water efficiency, and increase crop yield.
The design process began by developing a thorough understanding of the local context, through which the primary design objectives of affordability, accessibility, and water efficiency were identified and prioritized for both a physical irrigation system and an associated configuration tool. The final solution is a software that local farmers can use to design their drip irrigation systems. To use this software, the user inputs details about their farm including water resources, field dimensions, desired crops, and water emitter type. The program then calculates the flow rates of water throughout the irrigation network, the water supplied by various emitter types to individual crops, and the duration of time the farmer should operate the system for optimal water usage. Microsoft Excel was chosen to be our software’s platform because it is the most locally accessible, affordable, and familiar platform for the partner NGO.
In February 2018, the capstone team visited the town of Tipitapa in Nicaragua and used the developed software to design and construct a drip irrigation system on a local farm in collaboration with community members. Water savings of 21% were projected on that farm, thus reducing the risk of running their well dry. The software was also shared with the client and local NGO so that it can be used on future farms to develop more systems. Using this software, farmers can predict the output of a system prior to construction, thus allowing designs to be re-evaluated and iterated upon at no cost. Additionally, it allows farmers to develop an optimal crop layout and watering pattern, reducing the traditional reliance on intuition, the associated risk of over-supplying water, and the potential to empty their wells unnecessarily.