Mateves Rainwater Harvesting


Means to a Solution
A component of the Appropriate Technologies class was to have a focus project where, “students will work in groups of 3-5 on a particular challenge faced by a participant community.” A member of our group, Nicole, had spent a summer working at the Mateves village in Tanzania. After some deliberation on what we believed Tanzania could use help with, we learned that the amount of rainwater retention they have is low, and Tanzania has a long dry season because of it. Thus, a problem statement was created.

Problem Statement
The Mateves Village in Tanzania experiences flooding during the rainy season and droughts during the dry season. Due to scarcity of water in the dry season, crop yield is depressed leading to less food for the community. During the rainy season, the flooding causes nutrient leaching and soil erosion, leaving depleted soil. A system needs to be formed to help with water and nutrient retention for crops.

Background Information
The People of Tanzaniarainfall.jpg
The statistics of the people of Tanzania vary greatly from what we are used to in the United States and other more developed countries. The median age is 18.5 years old. With males at 18.2 years old, and females at 18.7 years old.
Tanzania does not have much in the way of usable land. In fact, only 4.23% of their land is arable, meaning that only 4.23% of their land is suitable for producing crops. And on top of that, less than 1% of their land is irrigated. From the land they do farm on, they produce many crops: coffee, sisal, tea, cotton, pyrethrum, cashew nuts, tobacco, cloves, corn, wheat, cassava, bananas, as well as other fruits and vegetables. They also have some livestock: cattle, sheep, and goats.
Overall, the work force in Tanzania is 80% in the agriculture business and 20% within industry and services. Since Tanzania has such an agrarian society, our group would like to help further promote these practices.

The Landscape of Africa
The landscape of Africa ranges from areas of stable soil to areas without any vegetation -like the Sahara Desert. For the country of Tanzania specifically, their soil is ranked as “Very Degraded Soil.” If our project were to succeed, we would hope that we could also improve the quality of Tanzania’s soil. Below is a map of the different levels of degraded soil of the world with Tanzania circled in blue.


Goal: Help People Help Themselves
The overall goal of our project is to help people help themselves. We plan to do this a few different ways including: providing on the ground skills and service training, extending their growing season, and educating the people of the Mateves Village on new farming practices and providing a service job to the people. We plan to achieve this by providing a simple, easily transferable solution to the Mateves Village.

The Case for Appropriate Technology
In the 70s and 80s, a serious drought caused crop failures and brought attention to this region. Accordingly, much research was put into rain water harvesting technologies. Unfortunately, most of these projects ultimately failed because they weren’t maintained by the local population.

There were a few examples of Rain Water Harvesting working, but these used traditional methods (e.g. stone lines in Mali, earth bunding – or swales – in eastern Sudan and Kenya.) It’s important to make sure that the technologies utilized are appropriate and that the locals are able to own the project – including maintenance down the road.

A Multifaceted Approach
To reach our goal, we have come up with three possible solutions.

  • Extend the Rainy Season
    • By extending the rainy season, we would reduce the dry season for the Mateves Village and hope to improve the quality of the soil. We would do this by increasing the water retention of the soil. The methods we would use for this solution would be swales and small depressions and weed control.
  • Protect Natural Resources
    • Protecting natural resources should help further with water retention and adding nutrients into the depleted soil. We would achieve this goal by using local, drought-tolerant plants to help control erosion.

  • Increase Soil Fertility
    • By increasing soil fertility we can also increase and prolong the growing season, producing more crops for the village. Which should help their agriculture industry as well. We plan to achieve this goal with biochar amended soil.

Weed Control
Weed control is an important aspect to our project because weed actually take water and nutrients out of the soil. So if there are less weeds overall, then there is more water for crops and more nutrients left in the soil.

From our own knowledge we know that a small amount of mulch -as much as 1.5 inches- depresses weed growth. The mulch could even be re-purposed agricultural waste (such as corn stalks). Manure is another option that would also create an increase in crop yield and weed control. It is an option that we would explore once getting on the ground in the Mateves Village.

Also, with either of these methods, we could even work towards an entrepreneurship project where locals could sell manure or agricultural waste for farmers to use.

Erosion Control and Permaculture
Swales are used to create a water harvesting ditch or contour that would prevent erosion and hold water. They are designed to capture and spread runoff horizontally across the landscape.
In arid climates, it is recommended to plant tress alongside swales. The trees will assist in rebuilding and creating more fertile soils. This would further assist in our overall goal of creating better soil for the Mateves Village.

Biochar Properties
Biochar helps with soil improvement in two main ways. It increases the soil’s capacity to hold nutrient and it increases water sequestration within the soil.Biochar also helps with waste management. To make biochar you can utilize agricultural and other organic waste. This helps because that waste, if not disposed of properly, has the possibility of polluting both ground and surface water which would not help the fertility of the crops.Biochar also uses syngas and biodiesel for energy production.

Biochar Amended Soil
“[Biochar] acts as a sponge in the soil, absorbing and retaining water, gases, and solutions…

biochar has no equal
-Morley, 1929

The Mateves Village requires a focus on Community.
Our solution must be community structured, so that one structure can service many families. It must be community built with resources such as mud or earthen bricks, and local materials. The community can assist in designing the brick casing and making the bricks. We can even implement a roof collection system for catching rain water. And our solution must be community serviced, supplying transport from the collector to the fields and community members that can patch the bricks.

The layout of our budge is as follows:
Meet with Users
travel ($1500/person)
lodging + food (TBD)
consult with experts (Bargain?)
Collaboration Partners
Re:Char (Biochar Company)
One Heart Source (Tanzania Aid organization)
Seeds + Seedlings (locally sourced)
Biochar Reactor (local materials)

Although we were unable to get verified prices for our budget, most of the money would be spent on transporting people to and from Tanzania so that we can lay out the ground work there.

Project development + proof of concept (20 weeks)
contact Mateves– One Heart Source
build Biochar reactor

Consultation + Collaboration (4 weeks) find local farmer to participate in pilot program community leader / entrepreneur to take ownership of biochar train and education community on agricultural system survey local experts on erosion control

Community Training (2 weeks) dissemination within the community
community ownership: locals teaching locals

Monitoring (5 years) quantify results + publication

Project Members
Scott Grandi-Hill– A graduate student in Soil Science with a focus on bioremediation and using vegetated waterways for waste and storm water treatment.
Leah Herbert— A Materials Engineering undergraduate student with career aspirations in renewable energy.
Nicole Esposito—A graduate student in Materials Engineering with a focusing on sustainability and renewable energy.
Amy Anderson— A sociology undergraduate student with aspirations to join a PhD program in the field of Engineering Education.