Presentation on theme: "Water Delivery Systems for Horticulture Production in West Africa"— Presentation transcript:
1Water Delivery Systems for Horticulture Production in West Africa
2Israel is a lucky country as far as water delivery goes Mekorot, its national water company is obliged by law to deliver water at a 4 atm. pressure to the fields of its customers.All what the farmers needs to do it to connect its irrigation systems (sprinklers or drip) to the main valve and start irrigating.However in most of the world the farmer is the one who needs to carry out all operations (drilling, pumping, deliver of water to the field) to allow irrigation of his field
3Water supply is therefore a central issue on the development of irrigated horticulture in Africa The issue of sustainable water supply is more critical with TIPA than it is for private sector irrigation because in TIPA water supply is a communally managed undertaking and therefore there is less personal responsibility for maintenance of pumps and water delivery network.The sustainability of TIPA is strongly dependent on the rigidity of pumps. For this reason electric pumps (powered either from the electricity line of from solar collectors) are preferred over other pumps.
4Since the AMG can be operated at very low pressure it can use low energy water sources In Ghana and Benin TIPA projects are using the height differences (3-4 meters) between artificial dams and the fields that lay downstream of the dam (hydraulic energy). In this case the energy is free, no need for special reservoirs and no pumpsIn Niger TIPA is using the energy contained in a very vast artesian aquifer situated meters below ground level. The water in this aquifer is under pressure and water raises on its own energy ( no need for pumps) reaching the surface with a pressure ranging from 2-10 meters at ground level. The artesian borehole can be combined with concrete water reservoirs to capture the water that flows at night when the fields are not being irrigated.
5Golinga Dam. Three meters above fields Golinga Dam. Three meters above fields. Sufficient pressure for AMG operation
6Vegetables. Foundation seeds production Golinga AMG clustersNote pipe connection on bottom leftVegetables. Foundation seeds production
9Artesian borehole in Niger Artesian borehole in Niger. Free water flow 24 hours a day 365 days a year
10Yelou- Gaya Region (Niger) 5 ha Cluster AMG, 500 m²/producer Pressure provided by artesian borehole (4-5 m head, 60 m3/hr)
11Electricity is not available in most Sahelian villages Electricity is not available in most Sahelian villages. In these circumstances solar power is a substitute for electricity.The prices of solar panels are steadily decreasing. In 2010 the price of a solar panel is half the 2009 price. If this trend continues very soon it will be cheaper and safer to use solar rather then electric energy from electricity lines to power water pumps.The low pressure drip system is ideal for solar pumps as compared with pressurized drip or sprinkler irrigation because the latter require about 30 meters pressure to operate, meaning using a large costly battery of solar panels.The use of solar pumps must be accompanied by water reservoirs because clouds result in variable pumping rates and elevated (1.0m) reservoirs give a steady water delivery. A reservoir can be regarded as a substitute for the non sustainable and costly batteries
12Tanka (Niger) 3 ha, 600 m²/woman Pumping at 7m hydraulic head- 90m3/day– 1.5 ha/day9,000 US$ including three 20m³ reservoirs
13Tanka village women welcome solar pumped water. Notice adjacent concrete reservoir
14In Senegal many TIPA sites receive water from elevated (15-20 meters) water towers used for village water supply. The village authorities are responsible for maintenance of the water supply thus guaranteeing sustainability of the water supply systems. Farmers pay for the water used directly to the village water authoritySome American NGOs are aggressively promoting hand pumps and treadle pumps for water delivery. These pumps are relatively cheap but they require a significantly amount of effort to operate and for this reason are disliked by farmers particularly by women. They are manufactured in local workshops and are of low quality. They break easily and are discarded by farmers
15Broken and discarded hand pump Thousands of those are littering theSahelian landscape
16Village water supply tower, the most common water source for TIPA-Senegal
17All four options for water pumping are only good for lifting water from shallow aquifers (≈10meters deep) When water is situated at greater depths one must resort to diesel powered or electricity powered pumps.
18Cost of water supply for irrigation of 1 ha in Niger qtyunitcosttotalamortz$$/yearEquipment121012060370210531400806,000600Well303609010030020020Water distr. network752252340Maintenance45Fuel1,920$/manday2,22224,4445561,1115013$/manday256Total4,6061,2612,255709@Labor 2$/day2,3847062,205696@Labor 1$/dayTreadle pumpHand liftingMotor pumpSolar pumpapptechdesign.org/