Entusi Model Farm

Acknowledgements

We would like to thank Tom Karrel, Raymond Bokua, Thomas Byonanebye, Nathan Davis, Anit Koirala, Kristoph Kinzli, Reza Hedayat, Beth Reddy, Alina Handorean, Global Livingston Institute, our donors, and the senior design advisors and teams for their continued support. Our project would not have been possible without their guidance and help along the way.

Video

Elevator Pitch

Farmers planting seeds on the Entusi Model Farm

The purpose of this project is to work with the Global Livingston Institute to develop irrigation and erosion solutions for the Entusi Model Farm near Lake Bunyonyi, Uganda. The solutions must not only work for the Entusi Farm; they should be easily reproduced on varied scales for neighboring farms in the region. Our team proposed four design solutions: check dams, semipermeable clay pots, a partnership with Volta Irrigation, and rainwater collection from roofs.

The check dams are the most feasible, cost-effective and safe solution to mitigating the erosion and irrigation problems on the farm. Check dams can be made of any local source material: stones, wood, concrete, or any recycled materials. These small dams store runoff from storms for a short period of time, increase infiltration, and redirect water towards crops. Additionally, check dams collect sediment that would otherwise be washed away, allowing farmers to collect this nutrient-rich soil and redistribute it to their crops.

The other three solutions (Volta irrigation, clay pots, and rooftop rainwater collection) are good alternatives for farmers that may not have the resources or manpower to create check dams.

Design Approach

Design Approach for the Entusi Model Farm Irrigation System

As part of the Engineering for Communities Design Studio the team emphasized the importance of satisfying the Bridger and Luloff criteria for sustainable community development in their design. These criteria focus on factors such as desirability, feasibility, and viability that are essential to consider in order to fully meet the needs of a community. Through conversations with GLI staff, the team developed a set of design criteria which was used to guide the design process. GLI also had conducted surveys from members of the farmer cooperative at Entusi and the feedback from the responses was also considered throughout the design process. 

Project design constraints include:

– Plot sizes of farms are 20 x 30 meters

– Cost to implement design per farmer: $15-$50 (per client request)

Project design criteria include:

– Robust and easily replicable

– Sustainable–farmers can maintain system on their own

– Meets water delivery needs for current crops

Initially, four concepts were considered in the preliminary design process: a system of check dams, a roof rainwater collection system, clay pots, and Volta irrigation. In deciding on a design, our team considered the design constraints and criteria provided by GLI. An assessment of how each design solution addressed these criteria is shown in Table 1. Each criteria was ranked on a score from 1-10, with 1 being the worst and 10 being the best. For example, under the Cost criteria, a lower score indicates a more expensive solution.

Table 1: Design matrix utilized to determine main irrigation concept

This analysis and decision to move forward with the check dam system design was approved by the client. This became the focus for the project with the hopes that future teams might also consider the other three design alternatives.

The validation process for the check dam system included researching case studies that had implemented similar check dam systems, reviewing calculations with our faculty advisor, and conducting extensive research on typical building regulations and guidelines for check dams. Case studies in Bamyan, Afghanistan and in the Sikar District, India showed an increase in irrigated farmland and subsequently, increased income after the implementation of check dams. There were also documented environmental benefits including flood mitigation and groundwater recharging. 

Design Solution

The team designed a system of check dams to store and distribute water throughout a given plot. The main goals of the check dams are to collect and store water and provide farmers with access to water for irrigation purposes. The system is designed to be adjustable for different sized plots, varying water requirements for different crops, and compatible with the addition of more robust irrigation methods for the future. 

Rendering of the channel and check dam system on the Entusi Model Farm, created by the team

Above is a rendering of the check dam system on the Entusi Model Farm site depicting the various components and showing the flow of water throughout the system. The check dams are able to be constructed from a mix of rock, soil, timber, and cement. In order to minimize risk, a maximum depth for each check dam was established to be 0.6 m (2 ft). Other risks such as mosquito growth in stagnant water and the coffee rust fungus were considered but our client informed us that they were not concerns in this region. For additional information about risk mitigation, reference the detailed risk analysis matrix attached to this website. The figure below also shows the dimensions for each individual check dam that would be installed on the ¼ acre plot. The sizing and layout of the check dam system are able to be altered to fit farm plots of various sizes, shapes, and slopes.

Drawing of the check dam structure, spacing, and calculations for the number of dams needed

Farmer relations are extremely important since the design will be on a model farm for learning the best techniques. A pamphlet, shown below, was created to communicate to the farmers what a check dam system is, how it will benefit their farms, and how they can implement it on their farms.  The pamphlet allows for quick communication of the design and initial feedback. Further testing with farmer feedback is necessary until the pamphlet can be finalized. The Swahili translations should be verified by a native speaker before publication. Additionally, rendering and drawings may be modified to more accurately fit farms outside of the model farm.

Click here to see our Risk Analysis.

Click here to see our Check Dams Instructional Pamphlet.

Rendering of Stone Check Dam

Next Steps

Further testing is needed to test infiltration of the soil and determine soil types. Infiltration rate will determine if additional design elements need to be implemented. Moving forward, calculations will have to be reviewed by a professional engineer to ensure that they are accurate. Further, all calculations will be compiled and archived to allow future teams to utilize the current designs. Additional farmer input also needs to be included to ensure that the final design is exactly what is wanted and needed by the community. Our hope is that with this information, the next team will be able to travel to Entusi to conduct the testing we were planning on doing, as well as any other necessary testing and complete one final design to be built at Entusi.

Meet the Team