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Words John Gray

Mohammad Tayy, Farid Abou Merhim, and Souhail Awad had always used water pumped from artesian wells to irrigate their farms in Lebanon. Mohammad and Farid operate coastal farms in Choueifat and Damour, while Souhail runs a farm in Kfarmashoun in the Mount Lebanon range. They use that water in their greenhouses, where they grow tomatoes, cucumbers, and strawberries year-round.

Well water no longer suffices

However, climate change has made such farming more difficult. December, January and February are usually Lebanon’s wettest months, and a crucial time for farmers, since rainfall and snowfall renews the water levels of wells. But in the last few decades, these months have seen marked decreases in precipitation and snow cover. Before the 1990s, an average of 2,280 square kilometers of mountainous areas had snow cover. This figure has since decreased to 1,925 square kilometers. The average time that the dense snow remains before it starts to melt has decreased from an average of 110 days before 1990 to an average of 90 days after 1990.   Wells are not being refilled as they used to be, forcing farmers to pump deeper and deeper. This is risky, as it not only means exploiting groundwater faster than it is being renewed, but it also risks digging too deep and introducing saltwater into the wells.

Mohammed says: “Things are the worst during the dry summer season. For the past three or four years, we have been forced to purchase cisterns of freshwater for irrigation at exorbitant prices because of chronic water scarcity and salinization.”

Harvesting rainwater

To counter this trend, UNDP partnered with the Lebanese Ministry of the Environment on a project to increase farmers’ climate resilience. Using funding from the Lebanon Recovery Fund, the project implemented rainwater-harvesting systems that sit on the top of greenhouses.  The installed technology is a direct pumping system, which consists of catchment half-pipe structures alongside the greenhouse tops that collect rainwater that is then held in a storage tank and pumped to the point of use when required. Water meters were also installed for monitoring water levels to track the technology’s progress.

Now Mohammad, Farid, and Souhail can collect the precipitation in large tanks and use the extra water to irrigate their crops in the dry months. During the last rainy season, the rainwater harvested from their 14 greenhouses reached 999,981.91 cubic meters. Mohammad says: “I am very satisfied. I did not need to purchase any freshwater tanks for irrigation this summer, thanks to the rainwater that I have been collecting and storing”. Mohamed plans on using the technology in another greenhouse site that he owns in southern Lebanon.

After monitoring the pilot sites during and after the rainy season, the volume of water collected at the Choueifat site was almost double the amount of water that was used to irrigate the selected greenhouses. The amount of water that is usually used to irrigate the greenhouses is 543.1 cubic meters, whereas the harvested water from the greenhouse tops amounts to 1,084.1 cubic meters. Therefore the farmer used the rainwater for his whole farm as an alternative to the saline groundwater. As for the Kfarmshoun farm, records showed a staggering collection of 999,840 cubic meters of water from the greenhouse tops, whereas only 1,204 cubic meters was needed. This in turn made possible the irrigation of the entire farm at Kfarmashoun. Farmers stated that the increase in water availability had enabled them to produce more at a reduced cost.

Vahakn Kabakian, UNDP project manager, says: “There are so many benefits. First, farmers are saving all the money that they used to spend on purchasing water for irrigation and for pumping. Second, the groundwater quality will be protected from pollution and salinization, since the pumping rate and depth will both decrease. Third, water quantity will be preserved, as natural recharge will be less disrupted by over-pumping. Finally, this initiative is an adaptation measure that has a great mitigation co-benefit, as CO2 emissions from energy consumed for pumping water will decrease.”

Harvesting rainwater from greenhouse roofs was one of the key adaptation technologies recommended in Lebanon’s Technology Needs Assessment. After the harvesting systems were installed, UNDP gathered the lessons learned from the installations and used them in guidelines that will provide information for similar initiatives throughout Lebanon. 

Samar Malek, head of the Department of Environmental Technology at the Lebanese Ministry of the Environment, says: “We are happy and relieved to see hints of solutions to the water crisis that has been putting the livelihoods of so many Lebanese farmers at risks. The positive feedback that we have been receiving from farmers is very reassuring.”

In order to replicate the success of the pilot project, a Rainwater Harvesting from Greenhouse Tops Manual has been prepared, based on the pilot experience, which will be distributed to local farmers. This initiative falls under the National Action Programme to Mainstream Climate Change into Lebanon’s Development Agenda. The main aim of this program is to build on the ongoing governmental projects, and the Rainwater Harvesting from Greenhouse Tops initiative fits into the Lebanese Ministry of Energy and Water’s strategy to reduce stress on groundwater resources, and the Ministry of Agriculture’s adaptation efforts.