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INTERNATIONAL COOPERATION ON WATER SCIENCES AND RESEARCHtial for dynamic development. The fundamental opportunitiesare resources: fertile soils, a long growing season and humanpotential. However, major threats in many regions are created bythe limited and poor quality of water resources due to progressivedeforestation and urbanization. This process is causing seriousmodification of the hydrological and nutrient cycles, which inturn determine soil productivity. Therefore, the key challenge forthe sustainable future of Ethiopia and Africa is the restitution ofwater and soil resources.Pilot ecohydrological research at a demonstration area in theBiofarm Centre in Asella (CentralEthiopia), where the water from the reservoir was not used bylocal people due to negative impacts on human health, demonstratedthree major impacts on the functioning of this ecosystem:• a decrease in reservoir capacity due to erosion and siltation• toxic algal blooms in the reservoir, mostly due to nutrientoverload by livestock• elevated concentrations of dioxins in reservoir sediments.All these impacts have been reduced by the implementation ofecohydrological systemic solutions.The first element of the system is the use of biodegradablegeotextiles for land erosion control and the reduction of lakesiltation. Geotextiles enhance the early stages of the plants’growth by stabilizing the soil and it moisture. After the two-yeardevelopment of the root system the geotextiles decay, enhancingthe ecological functions of the catchments and ecosystemservices for society.The second element is an infiltration dam. Thisenforces sedimentation in the impoundment and transferof water through the gravel fundaments to the rootsystem of vetiver grass at the wetland, helping to reducenitrogen and phosphorus concentrations and preventingthe occurrence of toxic algal blooms in the reservoir.Sediments deposited in the sedimentation zone, whichare supposed to contain high levels of nutrients, arerecommended to be used as fertilizer for restoring erodedland and for food and bioenergy production.The high rate of insolation and the interactionbetween plants and soil microorganisms in the wetlandarea also allow a reduction in dioxin-induced toxicityby accelerating photo- and rhizodegradation processes.Another part of the system is the construction of acow-watering system some distance from the river,where the manure is collected and digested for furtheruse as fertilizer. This reduces the direct nitrogen inputof cows into the river and reservoir.The proposed ecohydrological holistic approach wasbased on earlier experiences in the Pilica and SokołówkaRiver catchment in Poland. 25 The above solutions arefocused on the sustainable use of environmental potentialand the enhancement of ecosystem services forsociety, including health aspects (reducing the dioxinconcentration in the environment and foodstuffs) andimproving opportunities for income generation fromthe production of food and bioenergy.Use of ecohydrology based systemic solutions for reduction of sedimentation, eutrophication and dixin-induced toxicitySource: ERCE[ 303 ]