EcoStab

From 2012 to 2014 Dr. Koch was team leader of the ecological river bank stabilization program for the Niger in Mali.

At two different sites hybrid soil-bio-engineering measures have been tested for this purpose.

 

Koulikoro / interjacent horticultural strips

Vegetation cannot resist on the river banks because of divagating animals, playing children and an overall very high pressure on the strip of land. The site is used for transshipping sand from barges during the dry season.

The base of the installation is secured by a wall made from gabions or dry stone masonry. The rest of the slope is stabilized with traditional soil-bio-engineering measures. Adjacent fallow and eroded areas are treated and converted into horticultural land. Those sectors serve as an incentive to the local population. The income generated from these sites should in the long term ensure the preservation and the maintenance of the mechanical installations.

 

 

Kangaba / vegetative wing dams

Plants cannot spontaneously colonize the sand within the main stream bed because of the mechanical stress due to the annual inundations. You can find relicts of the former gallery forests still well anchored inside the river bed. The river construction matrasses are only 30cm above the natural surface. They only serve as a temporary means to install vegetation (planted and spontaneous). The actual dyking effect will be brought about by the vegetation.

The situation was particularly difficult because of annual flooding. The water stands up to 5m over the installations level for 6 month. Additionally the site is used for driving cattle during the dry season thus putting strong grazing pressure on all plants.