Ground catchment

#301Rainwater harvesting (cemented ground catchment)

also available for: Ethiopia, Uganda, Guatemala, Honduras, Tanzania

Applicable for:
Arabica, Robusta

301⸱AConcept

  • Saves water resources 
  • Provides water for irrigation 
  • Increases the coffee yield
  • Reduces coffee mortality 

Rainwater harvesting is a method of collecting and storing rainwater from the land surface or rooftops. Uses include water for irrigation on the coffee farm, livestock, and domestic use. The ground catchment technique that harvests rainwater from the land surface is mostly used for irrigation purposes while Rooftop catchment mostly serves domestic and household uses.

Rainwater harvesting is particularly helpful in dry environments. It can even facilitate farming where low and poorly distributed rainfall normally makes agricultural production challenging – provided additional factors such as favorable soils and crops are available.

But also in suitable coffee growing regions, climate change effects such as changing precipitation patterns, prolonged drought periods, and increasing extreme weather events are major risks for coffee production as they result in loss of yields and income. Irregularity in the timing and distribution of rainfall has placed a considerable strain on farmers who rely directly on rainfall to sustain their livelihoods.

Rainwater harvesting systems can provide enough water to supplement rainfall and thereby enable, increase, and stabilize coffee production.

It furthermore reduces the daily burden of women and girls who are often the ones fetching water from common water sources and carrying it over long distances. Rainwater harvesting relocates the water source directly to where the water is needed.

301⸱BTo be considered

There are various water harvesting designs. This tool uses a circular design because it is durable, gives maximum storage volume, is relatively simple to maintain, and leaks can easily be identified and sealed.

The storage structure can be of different sizes, depending on the expected water demand and the construction cost. The water demand should be assessed to plan the size of the water harvesting structure.

Unforeseeable events can occur, such as a miscalculation of the required material quantities, so that construction is delayed due to shortages. Or rain could interrupt the construction process. All of this should be taken into account in workforce and financial planning.

The harvested rainwater is a scarce commodity and should be used sparingly. In that way, irrigation with harvested rainwater is different from the conventional concept of irrigation farming, which is based on an adequate supply of water for the crop to maximize yield per unit area.

The water storage structure presents the risk of injury to children and livestock if it is not adequately secured. Therefore, a fence should be erected around the structure.

Evaporation can be high due to high temperatures and drought. Furthermore, the storage facility can be a breeding ground for mosquitoes. Therefore a roof or floating cover is recommended. One such floating cover is the Water Lily plant which absorbs unwanted oily substances and creams from the water, purifies the water surface of any dirt, and helps keep it clean.

Timing: The excavation of the pit should be done at the onset of the dry season. The plastering, and erecting of the wall and water inlet in the dry season, and before the onset of rains.

301⸱CImplementation

Materials

The circular rainwater harvesting tank described here can store about 15,000 liters of rainwater at a time. This is sufficient to irrigate 0.2 hectares / 0.5 acres of coffee for a dry period of up to 3 months.

301⸱1Preparation

301⸱2Procedure

Pit excavation:

Pit excavation for water storage construction

a photo of two men digging a hole
a photo of two men digging a hole
a photo of a hole in the ground
Tip

If termites are an issue in the region, the excavated pit can be treated with termite repellent before the next steps. It should be applied to the unplastered walls and bottom of the pit according to the recommendations of the selling point.

301⸱3

Plastering the inside walls:

Plastering the wall of excavated pit

People plastering the wall of excavated pit
People plastering the wall of excavated pit
a group of people are working on a large hole in the ground .

301⸱4

Erecting the protection wall:

Plastered and smoothened walls of the water harvesting structure

a large hole in the ground filled with water and bricks .
a large hole in the ground filled with water and bricks .
a large brick wall is being built in the middle of a field .
Attention

It is necessary for the water inlet to face it in the direction of the natural water flow.

301⸱5

Construction of the water inlet:

Water inlet on the water harvesting structure

a large concrete circular structure is being built in the dirt .

301⸱6

Inserting of mud filters into the inlet:

Waste items, as well as mud, sand, and gravel, are present in flowing water. If they enter the tank, they reduce its water storage capacity.

Mud filters constructed using bricks and mesh

a brick walkway is being built in the middle of a dirt field .
a brick walkway is being built in the middle of a dirt field .
there is a fence made of logs in the middle of the dirt .

301⸱7

Completed water storage structure left to set

Completed water storage structure left to set
Completed water storage structure left to set
a large circular hole in the ground with a concrete wall around it .

301⸱8

Water tank ready to use

a man is sitting on a rock next to a water tank .

301⸱9Application

Technician demonstrating how a flexi pump works

a man in a red shirt is working on a flexi pump
Tip

Drawn water can also be put in a mineral water bottle for Bottle irrigation.

301⸱10

For sustainability and durability, maintenance of the water collection and storage structure is necessary. The following tasks should be done occasionally:

Water Lily cover

an aerial view of a circular pond surrounded by banana trees .
an aerial view of a circular pond surrounded by banana trees .
a man is standing in front of a pond in a field .
Tip

It is recommended to establish a floating cover made of Water Lily plants, for example. It will absorb unwanted oily substances and creams from the water, purify the water surface of any dirt and help to keep the clean. Furthermore, it will reduce the breeding of mosquitoes.

301⸱DEconomic benefits

Lower renovation costs 

This tool increases the lifespan of the coffee trees. They need to be renovated less frequently which reduces the long-term production costs. 

Higher coffee yield

The effects of this tool can lead to a higher coffee yield and therefore a higher income.

Lower water costs

With this tool, less water needs to be purchased, reducing expenses. 

Time saving

This tool saves time and effort in day-to-day life.

301⸱EGreen benefits

Water saving 

This tool saves water as a scarce resource.

More water availability for irrigation 

This tool provides water for irrigation not only of coffee plants but of seedlings, vegetables, different companion trees and other vegetation types. 

Balances the local microclimate

This tool helps to grow diverse plants which help to balance the local microclimate. This helps mitigate several effects of climate change.

Higher biodiversity 

This tool helps form habitats for different plant and animal species to grow. This contributes to a healthy ecosystem.