Road water harvesting


Road runoff water is often speeding down the drain, quickly concentrating into erosion gullies taking the soils along. Instead of giving it a speeding ticket, you can also redirect the water. Away from the road, within the adjacent area. Not letting it go, but also not letting it affect your road and landscapes. A new type of road water management. 

The concentrated water along roads and road catchment can be harvested. This harvesting can be done with simple structures on and along the road. Think of trenches, mitre-drains, cross-culverts, storage ponds and the like. A combination of techniques can channel water from roads into retention/infiltration areas. Benefits include groundwater recharge, landscape restoration, increased road infrastructure longevity, and increased water availability for agricultural and domestic use. 

This presentation attached is held at the 2nd IRF Africa Regional Congress in Windhoek, Namibia. On July 11-13, 2017. It is on the beneficial use of road water for climate resilience and asset management. Sand-dam as road crossingRoad side diversion from drain to harvest water

Friso Vos de Wael's picture

Thank you for the articles and great pictures. One question, what technique would be the easiest for a person to apply without having any heavy equipment and hardly any manpower?

Valentin MUCYOMWIZA's picture
Thank you for this idea of road water management and I can tell you that the majority of people do not pay attention to this. Road water can be a solution to water scarcity problem (house hold use such as construction, irrigation, etc) instead of being a problem.Erosion and soil slide is mainly caused by road water if there is no appropriate drainage along the roads. In Rwanda, the capital of Kigali is hilly and new roads are being constructed. This may increase the quantity of water which was essentially from house roofs leading to excessive erosion as well as soil slide in the city. Good drainage,road water catchment and road maintainance can help in avoiding accident from people exposed to this. But the idea of collecting and using this available water is greater.
Luwieke Bosma's picture

Hi Friso,

In that case I would say a small lead-out ditch from the road drain into a farm trench can work well. This does not require much work, and if you make your trench a bit deep and shallow, it can store water for a longer time. Often a mitre-drain or side drain is in place as part of roadworks, which you can use to direct your water. Also making small (stone/soil) bunds to divert the water for example from a cross-culvert can do a great job, without much work/digging. 

I attach a brief technical hand-out with some examples.

Luwieke Bosma's picture

Hi Valentin,

Thanks for your reply, would be very interesting also to discuss on the opportunities for Rwanda. Let's discuss further! My email is