Constructing the roadside farm pond

Ponds can be constructed using road-building equipment as part of the road construction or rehabilitation contract. Alternatively, they can be made by land users’ initiatives, using earthmoving equipment or manual or animal labor.

After the site selection and pond shape and dimensions are decided, the pond site should be cleared of all stones and woody vegetation. The selected site should be free from vegetation, bushes and other obstacles. The site should be leveled so that the demarcation line of the pond area can be drawn.

Before construction of the farm pond, the proper layout should be marked on the ground. This can be done with the help of rope and lines, with lime powder, or by making small cuts. The idea is that the demarcation lines must be visible for the equipment operator, thus enabling him or her to excavate earth from the pond area. Stakes are used to mark the limits of the excavation and spoil-placement areas. The depth of cut from the ground surface to the pond bottom should be indicated on the stakes.

The use of a bulldozer for excavation is usually for medium-sized ponds, due to its inefficiency in transporting the material. If the excavated material is placed near the pond, it can be used as a berm or dike. After the earth is excavated, the subgrade and banks should be compacted.

When landowners develop ponds, they often use manual labor or tractor-pulled wheeled scrapers. An alternative method for developing ponds is to make use of animal traction with the help of scoops. This method is less common than expected but has greater potential.

Developing a roadside pond with oxen scoop and compactor in Tanzania
Developing a roadside pond with oxen scoop and compactor in Tanzania

The following are the main do’s in using animal traction for farm pond development (see Annex 4):

  • For animal digging, use staged ramps and develop the pond in layers.
  • The area to be excavated is to be softened by plowing to a depth of 20-30 cms. This can be done by an ox-drawn plow attached to one or two oxen pairs using normal yokes. It is important to plan the space to enable easy turns for the animals.
  • The softened soil is removed with the ox scoop. To load the scoop, the operators simply raise the handles of the device to augment the incidental angle between the soil and the scoop. The forward movement of the animals will do the rest. Once the scoop is loaded, the handles are lowered again, and the scoop will be pulled until the disposal area is reached. To offload the soil, the operators need to raise the handles until the scoop topples together with its load. These scoops are not usually available but can be made in local workshops.
  • Excavated soil needs to be properly disposed of and is commonly used to build a berm around the pond. It is important to compact the berm to avoid erosion problems. A simple roll compactor can be built with secondhand bearings, scrap metal, and an old oil drum. The drum is filled with sand and rotates as the oxen pull it.
Farmer extracting water with a diesel pump
Farmer extracting water with a diesel pump