A sand dam is a rainwater harvesting structure built across seasonal river bends_ in arid and semiarid regions.The structures are made of a structural wall that traps the sand from water flowing downstream, a shallow well or sump can be used as the draining point, from where the filtered water is abstructed by use of a hand or solar powered pump.In other more basic sand dams, the communities can still draw water from the sand dams through the traditional scoop holes.
How the Sand Dams made
The sand dam structure(wall) is made of two basic parts,the spill way,and the two wings at each side.While the spill way allows for the natural flow of the river to continue,the wings serve to concentrate the flow on the river channel and protect the sides from erosion.The sand collects on the upper side of the dam wall, while the over flow continues down stream.Technical considerations are however critical to ensure the structural tenacity the wall needs inorder to bear the force of the water.
The sand dam structures are a multifaceted tool of addressing water shortage,food security and soil conservation.They are also having a positive impact on Education more so for the girls in the community,as they no longer have to spend hours fending for water.Other direct impacts include climate change resilience,disaster risk reduction,improved sanitaion and hygiene among many others.
Traditional scoop holes.
With the water nearer the surface,communities can now draw clean,sufficient water from the traditional scoop whole with a lot more ease than it used to be before the sand dams were constructed.
Along with the Sand dam,ASDF supports the community with the construction of the shallow well which is then fitted with a hand pump for easier access of the water.
Solar pumping system
In some sand dams,we have been asssting the community access the harvested water a lot more conveniently by installing solar powered water pump which pipes the water to more central poits and much closer to the beneficiary homes.