On a global scale, population growth, changing food consumption patterns and climate change will severely impact the availability of water resources and are highly likely to exacerbate conflicts between "drinkable water" and "agricultural water". Etc Terra implements Integrated Resource Management projects (IWRM) to prevent such conflicts and to reconcile water security and food security.
- 88% of the water used worldwide is used for rainfed and irrigated agricultural production (IWMI 2007)
- Agricultural production must increase by 70% globally by 2050 to meet the growing food needs and it will double in developing countries (FAO-SOLAW 2011)
Etc Terra fully supports the definition proposed by the Global Water Partnership (GWP) which designs IWRM as "a process which promotes the coordinated development and management of water, land and related resources, in order to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems".
Etc Terra's action plan
Like the Zambazamba project, Etc Terra works preferentially in synergy with Safe Water Supply projects implemented by partners such as Decentralized Cooperation and Water Agencies.
On targeted watersheds, in order to be fully compatible with an IWRM approach, the first step is to gather all the local stakeholders around this concept and to implement this common approach by developing a management plan watershed.
Consecutively, two major types of perfectly complementary activities can be implemented:
Protection and increased upstream resources
Watershed management © FIBL/FTA
Watershed management © FIBL/FTA
On watersheds located upstream sources, every action limiting evapotranspiration of the ecosystem while promoting the infiltration of water at the expense of runoff acts positively on both volume and quality of the captured water.
From this point of view, it is a permanent cover which is clearly the most effective solution because:
- The foliage protects the soil from the impact of raindrops while the stems and superficial roots constitute obstacles to surface flow which reduces the speed of the water streams and hence erosion;
- The deeper roots of trees (or herbaceous) increase soil permeability. These plants favor the incorporation of organic matter from recycling plant debris fell to the ground (leaves, branches) which improves soil fertility.
Efficient use of water resources downstream
This is primarily to increase agricultural water productivity, ie the amount of seeds and/or leaves produced per m3 of water. "More crop per drop", is the goal through the promotion of various agro-ecological practices:
- Intensive Rice growin System (SRI): lining out widely spaced, alternating periods of irrigation and drainage, addition of organic manure and advice mechanized hoeing. Cconducted in eight countries in Asia, a recent study on SRI showed that the system allows an average water savings of 40% and a higher average yields of 47% compared to conventional systems (Africare et al. 2010);
- Drip-drop:systems: irrigation water supply at low pressure at the base of plants through distribution dropper with small pipes laid on the ground or buried;
- No-Till systems: direct seeding, soil cover by crop residues or plant, crop rotation;
- Zaï: digging a hole or planting hole in which organic fertilizer and seeds are deposited (on degraded and compacted land).
Depending on the project objectives and activities implemented, various hydrological measuring devices can be set up:
- Comparative measurement of rainfall and flows through instrumentation of sources and/or outflows;
- Measuring the reduction of runoff (and erosion) through the installation of lockers lysimetric downslope;
- Measuring the reduction of Evaporation and Transpiration calculated by empirical formulas mobilizing various climatic factors (average temperature, sunshine duration, relative humidity, average wind speed, etc.);
- Measuring improvement of useful water reserve in the soil.
Beyond the impact measurement in situ, the results of this scientific work should allow to build a concrete argument on Payment for Environmental Services (PES) linking the cost of the upstream watershed management with the profits derived from them by downstream users (agriculture and Supply of Drinking Water).