Efficient water use on the farm

Backgrounder

Key information

To make the most of what rain does fall, there are several strategies for collecting and managing water at home and on the farm, including harvesting rainfall, preparing land to control drainage, and irrigating crops.

Water tanks and irrigation
One easy technique for collecting rainwater is to add gutters under the eaves of a metal roof. The rain can flow down the gutters into a holding tank. It’s a good idea to add fine mesh before the water enters the tank to prevent leaves and other debris from entering the tank. Ensure the tank has a removable cover to reduce contamination, prevent mosquitoes from breeding, and allow easy access for cleaning. Consider also a first-flush diverter, which is a simple, low-cost device that discards the first few litres of runoff from each rainfall (which wash dust, bird droppings, and debris off the roof) before clean water enters the tank. This is a standard addition in most rainwater-harvesting guidance and further reduces contamination risk beyond the mesh filter. This water is great for washing and watering plants near the house, although it should be filtered and boiled well before drinking or cooking.

Farmers can also dig a pit to collect rainwater. The pit should be lined with heavy clay or plastic to prevent the water from soaking into the ground. This water can be used for irrigating crops, and if the pit is big enough, it can also be used for raising fish – as well as

irrigating crops. These irrigation pits should be cleaned before the rainy season, and the organic matter at the bottom makes an excellent fertilizer.

This interview script explains these water management practices and more in more detail.

Digging canals is another great way to help water drain from the soil, and to capture runoff water and groundwater. Farmers can dig long, deep canals diagonally across their sloped field, and set long, flat stones on both sides of the canal, as well as on top to cover. Adding more soil on top will bury the canal several metres under the soil. Have the canals lead to dug out pits. Learn more from an Ethiopian farmer in this issue pack

Farmers can connect these water tanks or wells to drip irrigation. Small pipes, called drip hoses, snake through the rows of the field, particularly for vegetables like tomatoes, beans, and cabbage. The pipes have small holes spaced every 30 centimetres or so. This allows water to slowly drip out of the hose into the soil. In this way the plants get enough water, but the farmer doesn’t use too much. Drip irrigation, however, can be a considerable investment and requires significant labour.

Alternatively, farmers can set up pitcher or clay pot irrigation. Farmers bury clay pots in the soil next to vegetable seedlings. When the pots are filled with water, the water slowly seeps through the walls of the pot into the soil. This reduces how much water is lost due to evaporation. Ensure the pot is covered to prevent mosquitos from breeding.

This host discussion describes both irrigation techniques. Access Agriculture also has good videos on both types of irrigation.

Irrigation can be supported by treadle pumps, hand, motor, or solar pumps. Farmers should also practice irrigation scheduling — using simple methods like the finger/soil-feel test, or low-cost soil-moisture indicators, to water only when and as much as the crop needs. This helps farmers avoid both waterlogging and the overuse problems described below.

Challenges with irrigation: Overuse of water through irrigation can deplete surface and ground water. Using fertilizers or agrochemicals can result in chemicals accumulating in reservoirs. Demand for water can be a source of conflict. Finally, irrigation with stagnant water can contribute to the development of water-related diseases such as cholera, diarrhea, or schistosomiasis.(2)

(2) How farmers can adapt to climate change in Burkina Faso. Farm Radio International. 2 December 2022. https://scripts.farmradio.fm/radio-script/farmers-can-adapt-climate-change-burkina-faso/

 

Surface water harvesting

There are several techniques that farmers can adopt to slow down rainwater as it runs off the fields.

Zai pits: Planting pits measuring approximately 20 x 20 centimetres with a depth of 10 centimetres, although pit dimensions can vary. The hole is filled with crop residues or manure, as well as seeds. Encourage farmers to adapt pit size to their own soil, rainfall, and labour capacity rather than treating one figure as the only correct size.

Half-moon ditches (demi-lunes): Semi-circles dug into the soil across the slope of the field measuring one to five metres. They should be constructed in staggered lines, so that when water fills one, it runs off the side of the ditch and it is captured by the next. Manure is mixed into the soil.

Stone lines: Built across moderately- to steeply-sloped fields to slow down water runoff and protect against erosion.

Contour farming: Till, plant, and harvest along the natural elevation lines of a sloped field, rather than in straight rows. By following the contour of the land, the rows help to slow water runoff and promote deep soil infiltration.

Tera: A U-shaped earth bund is constructed with the top of the “U” facing upslope towards the catchment. The bund traps runoff after rainstorms from catchments which are usually about five to fifteen times the size of the cultivated land area. The most complicated part of building a tera is achieving the right “fit” between the slope, the catchment, the directional orientation and the size of the tera. Farmers spend a great deal of time fine-tuning their designs. Because of the labour required to build such embankments, the cropping area tends to be small – perhaps one hectare in size.

Fanya juu and fanya chini terraces: Widely practiced in Kenya, Tanzania, and elsewhere in East Africa, a ditch is dug along the contour and the soil is thrown either uphill (fanya juu) or downhill (fanya chini) to form a bund, often stabilised with napier grass or similar. Find more information on this practice.

Sand dams: In semi-arid areas with seasonal sandy riverbeds (common in Kenya, Zimbabwe, and parts of the Sahel), a low concrete or stone wall built across the riverbed traps sand during floods. Water stored within the sand is protected from evaporation and can be drawn out through a pipe or shallow well for months into the dry season. Excellent Development / Sand Dams Worldwide (excellentdevelopment.com) specializes in this technique.

For land preparation, farmers whose fields are moderately- to steeply-sloped should protect their soil against this erosion by building contours or bunds across their fields. These can also be soil banks, sandbags, or stone walls. Building these structures will slow down the rainwater as it runs off the fields. This means that the soil will stay moist for longer, and, crucially, it will allow farmers to direct all the water that would have been wasted into areas where water is needed, or to be stored for later use. Learn more about contour bunds.

If building half-moon ditches or demi-lunes, dig several across the slope in staggered rows. The earth bund downslope of each demi-lune must be tamped down. This helps the demi-lune better resist runoff. The earth bund downslope of the demi-lune should be 30 to 60 centimetres wide. You can reinforce the bunds by placing stones or perennial grass seedlings such as bluestem on with a line of stones or with perennial grass seedlings such as bluestem. This helps the earth bunds better resist water runoff.

For soils so badly degraded that water cannot penetrate, farmers can dig zai pits to catch and hold runoff water. During the dry season, farmers dig a hole that measures 20 x 20 centimetres to a depth of 10 centimetres. The hole is filled with crop residues or manure. These materials attract termites, which make holes in the pit. The termite holes increase the amount of water that can penetrate the soil when the rains come. Millet and other crops are planted in the zai holes. In Burkina Faso, farmers using this method have improved their yields several times over. The zai holes also protect seedlings from strong winds. Even when rainfall is much lower than normal, zai holes have worked well in most cases.

This interview script explains these land preparation practices in more detail, as does this two-host discussion on strategies for adapting to climate change. This interview script shares the experience of Ugandan farmers in the hilly region of Mt. Elgon.

Small-scale and community irrigation systems

This issue pack does not address collective water systems, including dams, pump schemes, and river diversion. These systems require collective action and significant construction, operation, and maintenance costs. Good community engagement and collective ownership is important for a successful project. Learn more about Water User Associations from IWMI.org.

Find more details in Irrigation Techniques for Small-scale Farmers: Key Practices for DRR Implementers.

Gender equality and inclusion considerations

When talking about farming in general, it’s important to consider the gender division of labour; control over resources and assets, including income; decision-making power; time use and unpaid care work; and gender positioning in the value chain. When discussing water harvesting, it’s important to consider whether women have access to the funds required to invest in collection systems, or a role in decision-making at the family or community level. When discussing land preparation practices, it’s important to consider how labour-intensive these practices are.

In general, when discussing drought, access to water, and water collection, it’s important to consider the amount of time that is spent collecting water for farm and household needs, and who is typically responsible for this work. In many places, it is generally women and youth who are responsible for these activities, meaning they will benefit most from improved water collection practices. A UNICEF / WHO report found that, worldwide, women and girls spend a combined 200 million hours every day collecting water. In rural sub-Saharan Africa, the average round trip takes about 33 minutes, and across 24 surveyed countries, an estimated 13.54 million women and 3.36 million children are responsible for water-collection trips exceeding 30 minutes each way. (3)

(3) “Progress on Household Drinking Water, Sanitation and Hygiene 2000 – 2022: Special Focus on Gender.” UNICEF/WHO. 2023. https://www.who.int/publications/m/item/progress-on-household-drinking-water–sanitation-and-hygiene-2000-2022—special-focus-on-gender

 

Water treatment and use

Because water plays a role in the transmission of many diseases, health is always a concern when using a rainwater collection system. Storage tanks and surface water reservoirs can host disease vectors: mosquitoes for malaria and dengue, snails for bilharzias. Hookworm spreads easily in muddy areas. Algae grow in nutrient-rich, still and shallow water exposed to sunlight. Excess standing water can lead to health hazards and be contaminated by livestock. Thus, it is important to take steps to ensure water safety. Rainwater collection surfaces must always be kept clean. Tanks should be designed to protect them from infestation by leaves, dust, insects, vermin such as rats, and other pollutants. Because algae grow with access to sunlight, it’s a good idea to keep storage tanks in a dark place, which also keeps the water cool.

All tanks should be carefully sealed, and all openings fitted with mosquito-proof screens.

If collected water is to be used for drinking and cooking, it is essential to monitor water quality, and water treatment is advised. It is recommended that a basic water quality test be carried out on collected rainwater during the first year following the completion of a harvesting system. Further testing, including for the presence of mosquito larvae, is necessary whenever the quality of the water is in doubt.

 

Program design

This is a suggestion for how you might plan an episode on this topic, and some information to research and include in the episode.

1. Episode introduction: Include information on how drought has impacted your local area. How much rainfall has fallen in the recent season? Did it fall when expected, or were there delays?
2. News (Farmer story): Share the farmer story below or your own interview inspired by the story. Capture the experience of one or more farmers, but also try to find a farmer who has found success and share more about their strategy. Ensure your intro and extro mention the strategy for success this farmer has used.
3. Radio spot: Share key information as a radio spot. This might be a summary of the steps of one practice to harvest or utilize rainwater, such as in the Key information section. Or a dramatized radio spot promoting the practice of water harvesting through the experience of a (fictional) farmer.
4. Information interview: Depending on time, select one or more people to interview.
   (a) Interview a farmer about how they are harvesting or utilizing rainwater. This could be about land preparation techniques, building rainwater harvesting systems, or irrigation techniques.
   (b) Interview an agricultural expert from a research centre or government about water management practices in this area. This should be on the same topic as the discussion with a farmer, and touch on best practices and supports available for the community.
   (c) Interview a community leader about how they manage shared water resources and what water management techniques are working best for people in their area.
5. Audience interactivity: Invite your audience to call in to share their experience during periods of low rainfall and what techniques they find most promising for managing water. Alternatively, invite your audience to share their challenges in accessing water, particularly water from shared sources. This can be done as a call-in or vox pop and can be shared with community leaders and local government to inspire change.
6. Extro: As you wrap up the episode, ensure you summarize key information from the farmer story and interview.

 

Radio spots

1) Rainwater harvesting #1

NARRATOR:                How can water from the rains be harvested so that farmers can use it during a dry spell? Here are three major ways.

One: Identify slopes on the farm and dig trenches along the slope to direct rainwater into a constructed reservoir or dugout.

Two: Create dugouts on the farm to trap the rains. If your soil does not contain a lot of clay, line the dugout with polythene sheet to hold the rainwater and prevent seepage.

Three: Collect rainwater from rooftops on farm structures in a cistern  or other appropriate vessel.

2) Rainwater harvesting #2

FARMER 1:                  Ah my dear! Look at that sky. Not a cloud to be seen. And it should      be the start of the rainy season. Tsk. I am so worried about my crops. What will we do without rain?! Nothing will grow if it doesn’t get water.

FARMER 2:                  I know what you mean. Each year it’s so uncertain when we should      plant and will we get enough rain. But that is why I’m getting a tank for collecting water.

FARMER 1:                  Really? How will that help?

FARMER 2:     When it does rain, the rain will pour from my roof through the gutters  and downspouts into a huge water tank. It can hold 100,000 liters of water or more. Then I can use it to water my garden at least. That way I am sure to get some vegetables for dinner.

FARMER 1:                  That is good, so at least your family will be fed. But what about your  field? We need the maize too.

FARMER 2:                  Yes, I am hoping to get an irrigation system too that connects to the  water tank.

FARMER 1:                  Aaah. I hope for the best. I should look into this idea as well, because  when it does rain, it will pour.

3) Rainwater harvesting #3

NARRATOR:                Harvesting rainwater helps when the rains fail or when there’s not enough rain to meet crop demand. It can also help you grow lucrative out-of-season crops with big market demand. And harvesting rainwater reduces the time you spend fetching water for the household.Here are three ways to harvest water.

First, you can catch rain in gutters that redirect water into tanks.

Second, you can collect rain and groundwater run-off in water pans, ponds, or earth dams.

Third, in semi-arid areas, you can dig holes such as zai pits that catch water and hold crops. Also, runoff water from roads can be diverted to the nearest farm.

Don’t waste precious rainwater. Store it and use it when you need it.

4) Land preparation to manage the water #1

NARRATOR:                Farmers, make the most of the rain when it does fall! If your field is         moderately- to steeply-sloped, protect your soil from washing away with the rains. Build contours or bunds across your fields. These can be soil banks, sandbags, or stone walls. Building these structures will slow down the rainwater as it runs off the fields. This means that the soil will stay moist for longer, and, crucially, it will allow the water to  be directed where it is needed.

5) Land preparation to manage the water #2

NARRATOR:                Farmers! Consider your soil when you are preparing your land!

If your field is sloped and hilly, plough across the slope or along the contour, creating steps in the slope. This will reduce erosion during heavy rains. Running water will gather less speed and wash away less soil. You can also build bunds from soil or stones to slow water runoff.

If your soil is easily compacted, avoid heavy machinery like tractors. This will make the soil more compacted, which doesn’t allow rainwater to be absorbed. Incorporate organic matter to break apart compacted soil.

For light soils, use conservation agriculture practices such as minimum or no tillage, instead of ploughing. This is because light soil can be washed away after ploughing. Organic matter can also help  light soils.

And do not build bunds at land preparation unless your soil is more than 75 centimetres deep. Bunds are also generally not recommended for deep, black clay soils (vertisols), because they drain poorly and can make the bund unstable

When land is poorly prepared, farmers may sow unevenly, resulting in low density plantings and low yields. So pay attention to the nature and type of soil for improved yields.

 

Farmer stories

Burkina Faso: Farmers build rainwater collection basins to cope with droughts
By Ouabouè Bakouan, published June 19, 2025

Rainwater can be a great source of water, if it can be stored. While the first rains have begun to fall, Mwintio Somda waits for the rainy season to be in full effect. But his yam field already has fresh green leaves, as he has been able to water his plot with water he collected in a rainwater collection basin.

Built with support from a local project, the 200 m³ basin stores enough water for him to water his crops for up to 21 days. The basin measures 8 by 13 meters and is 2 meters deep. To prevent seepage, he lined the bottom with a plastic tarp. It’s fitted with drainage channels that direct rainwater into the basin, and a layer of stones at the entrance helps filter out plant debris.

Mr. Somda, like other farmers, received free materials through the partner organization’s project, including a plastic tarp, motor pump, 60-meter roll of wire mesh, tar, shovels, wheelbarrows, digging bars, and 60,000 CFA francs ($103 US) to cover labor costs. He estimates that constructing a basin—including soil studies—costs between one and two million CFA francs ($1,730 to $3,460 US), depending on its size.

Since building his basin, Mr. Somda has expanded his production area and improved his yield. He now grows maize, rice, yams, and vegetables on nearly five hectares. He says, “My crops no longer suffer from erratic rainfall.”

Read the full story.

Burkina Faso: Farmer improves soil fertility with stone lines, zaï pits, and half-moons
By Harouna Sana, published June 11, 2023

In the village of Mogtédo, as elsewhere in Burkina Faso, the land is degraded and impoverished due to climate change and poor agricultural practices. But many farmers are using stone lines, zaï pits, and half-moon ditches to enrich the soil and get the most from their field. Saydou Pacéré has a four-hectare field. He says “It is difficult to produce now if we do not adopt agricultural techniques of enrichment and water retention.”

Mr. Pacéré digs holes on parts of his plot that are lined with stone barriers. These are called zaï pits. The holes are in a line or staggered and spaced at least 50 centimetres apart. They are 40 centimetres in diameter and 20 centimetres deep, and are designed to collect and hold rainwater. Farmers add compost or other organic fertilizer and then plant seeds in the pits with the first rains.

Mr. Pacéré also uses half-moon ditches. These are large, semi-circular holes, four metres in diameter and 25 centimetres deep. They are oriented in the field in the same way as zaï pits, and filled with soil mixed with organic fertilizer.

Mr. Pacéré produces his own composted manure by mixing crop residues, grasses, and animal droppings in a pit dug in the ground. He waters and stirs the mixture for at least 10 weeks to obtain finished compost.

These techniques have helped farmers recover at least 46% of the degraded soil in Burkina Faso.

Read the full story.

 

Suggested interview questions

Ask farmers in your area:

• Do you collect rainwater? What methods do you use?
  • How did you set this up : What equipment did you purchase? How much did it cost? How much water do you typically collect? How do you use this rainwater?
• Has changing rainfall patterns affected your farming practices?
• How do you water your crops: Do they rely only on rainwater, or do you irrigate in some way? Do you feel you have sufficient water for your crops?
• How do you ensure you use water efficiently?
• What are the challenges for setting up irrigation or water collection ponds? Is this a strategy you have considered, why or why not?
• What did it cost to set up your water harvesting or irrigation system?
  • Did you get support from government, an NGO, or a savings group (e.g. a village savings and loan association) to afford it?

Ask local leadership / government representatives:

• What activities are being undertaken to collectively manage common water sources, like a local river? How is the community ensuring that everyone can benefit?
• Is there any effort to protect water sources from pollution?
• Are there any supports for farmers looking to set up water collecting systems or irrigation systems?

Ask agricultural officers:

• What water harvesting techniques do you recommend for farmers in this area?
  • Are there certain land preparation practices that work best in this area? What are key steps of this practice?
  • What are key points that farmers should remember to be successful with this practice?
  • Do you know of any farmers being successful with this practice?
• Are there any supports / funding for farmers looking to invest in irrigation systems or water collection?
• What action is being undertaken to collectively manage and protect local water sources, like rivers?

 

For more information

Africa Water Facility    | africanwaterfacility.org

Established in 2004, the African Water Facility seeks to support projects for water security and safe sanitation.

AGRA                          | https://agra.org/

AGRA is a proudly African-led institution focused on scaling agricultural innovations that help smallholder farmers towards increased incomes, better livelihoods, and improved food security.

Email: info@agra.org
Phone: +254 703 033 000

AidEnvironment          | aidenvironment.org

This not-for-profit has a few water harvesting projects in Sudan, Benin, Burkina Faso, and other places in the Western Sahel.

+256 (0)393 20 88 17
eastafrica@aidenvironment.org

Biovision Africa Trust.             | biovisionafricastrust.org

Biovision Africa Trust (BvAT) is a not-for-profit organization established in Kenya in 2009 by the Biovision Foundation for ecological development in Switzerland and supported by the International Centre of Insect Physiology and Ecology (ICIPE) in Nairobi.

info@biovisionafricatrust.org
+254 719 052 113

Kenya Rainwater Association            | kenyarainwater.org

This national membership organization is working to provide safe, reliable, and sustainable water supplies to Kenyans. They promote water harvesting education, community engagement, and implement water harvesting projects.

info@kenyarainwater.com
+254 737 916077

The Muonde Trust      | muonde.org

The Muonde Trust is a community-based organization in Zimbabwe dedicated to development in the Mazvihwa and neighbouring areas.

Ugandan Water Project          | ugandanwaterproject.com

This non-profit is working to build infrastructure to relieve immediate water insecurity. This includes rainwater collection systems, borehole wells, and solar-mechanized solutions.

info@ugandanwaterproject.com
+256 0759 037 674

International Water Management Institute (IWMI) | iwmi.org
A CGIAR research organization with practical resources on small-scale irrigation, water storage (including sand dams), and community water governance across Africa.

Landscape Alliance, formerly World Agroforestry (ICRAF) | worldagroforestry.org
Researches and promotes agroforestry practices that improve soil moisture retention and reduce erosion, complementing the land-preparation techniques in this pack.

Excellent Development / Sand Dams Worldwide | excellentdevelopment.com
Specializes in community-built sand dams in semi-arid East Africa, particularly Kenya, with practical construction guidance.

IGAD Climate Prediction and Applications Centre (ICPAC) | icpac.net
Regional centre providing seasonal climate forecasts and drought early warning for the Greater Horn of Africa.

Famine Early Warning Systems Network (FEWS NET) | fews.net
USAID-funded network providing food-security and drought early-warning analysis across many African countries.

 

Sources of information

Key resources from Farm Radio:

1. Burkina Faso: Farmers build rainwater collection basins to cope with droughts. Ouabouè Bakouan. Barza Wire. 19 June 2025.
2. Burkina Faso: Farmer improves soil fertility with stone lines, zaï pits, and half-moons. Harouna Sana. Barza Wire. 11 June 2023.
3. Stone Lines Reduce Erosion. Farm Radio International. Erik Nielsen. 1 January 1997.
4. Use half-moon ditches to prevent soil erosion. Erik Nielsen. Farm Radio. 1 October 1996.
5. Water harvesting: Issue pack. Vijay Cuddeford. Farm Radio International. 30 April 2012.
6. Community mobilization around water. Harouna Sana. Farm Radio. 11 September 2024.
7. Farmers improve yields with traditional soil-building practices that restore and fertilize damaged soils. G. Adama Zongo. Farm Radio International. 24 March 2015.
8. Guardians of the green: Tackling invasive alien plants to address water scarcity in South Africa. Lungi Langa. Farm Radio International. 3 October 2024.
9. Water-efficient gardens: Water is life. Paddy Roberts. Farm Radio. 23 September 2016.
10. Farmer strategies for adapting to climate change in Niger. Vijay Cuddeford. Farm Radio International. 2 December 2022.
11. How farmers can adapt to climate change in Burkina Faso. Ouaboué Bakouan. Farm Radio International. 2 December 2022.

Other key resources:

• Manual: Irrigation Techniques for Small-scale Farmers. Martin Smith, Giovanni Munoz, and Javier Sanz Alvarez. UN Food and Agriculture Organization. 2014.
• Poster: Water harvesting techniques. Biovision Africa Trust. March 2020.
• Manual: A construction documentation for the promotion of 3R (recharge, retention and re-use). Paito Obote, Ronald Ssebuliba. Uganda Rainwater Association. 2013.
• Video: Farming in Zambia: Drip Irrigation Systems. Mondo Farms. 2024
• Video: Half-moons: The Maasai secret weapon. BBC Africa. 21 November 2023.
• Video: Rainwater harvesting empowering women and building climate resilience in Zimbabwe: Muonde Trust. UNDP Climate. February 2026.
• Video: Rainwater harvesting: Stone lines and Zai planting pits. Access Agriculture.