As the winter months approach and settle in, so too comes the heavy rain and its familiar side effects—urban flooding, including instances of flooded streets obstructing traffic, and residents fleeing their flooded homes. Beyond the impact to residential areas, agricultural fields have also been affected more frequently in recent years thereby disrupting the livelihoods of the farmers and damaging the fruits and vegetables we all eat.
“When large areas of land are flooded, there is a danger of damaging crops that are susceptible to lack of soil ventilation or excess water,” says Dr. Roey Egozi of the Soil Erosion Research Station in the Department of Land Conservation and Drainage. “Trees may be uprooted, and crops may be torn apart.”
One major solution used by farmers to prevent the lack of aeration in soil and to protect the roots in the process is to create rows of artificially raised areas in the soil where crops or trees are planted. That way when it rains, the water does not weigh down on the roots, but instead flow to the furrows between the mounds where it can accumulate.
Beyond that, farmers are advised to take into account possible flooding when choosing what to sow in their field. “The type of growth needs to be adjusted to the potential risk of flooding in the area where they are planted,” says Egozi. “There are crops that are more susceptible to flooding, such as avocados or deciduous trees. So, if you plant a sensitive orchard near a stream that could overflow during rain periods and flood its surroundings, some trees may experience severe stress and mortality.”
In addition to the steps farmers take to limit flood damage, multiple drainage authorities operating through municipal runoff treatment channels work to prevent flood damage from taking a toll on cropland. Flooding usually begins as a result of heavy rainfall combined with the impermeable composition of asphalt and concrete, preventing rainwater from seeping into the ground.
“Migdal HaEmek, for example, is currently building a neighborhood that produces very large amounts of runoff, and as a result the agricultural areas down the neighborhood are flooded,” says Haim Hemi, director of the Kishon Drainage and Streams Authority. “However, today we are building a system to regulate floods in the area in collaboration with the Ministry of Housing. We are creating a kind of terrace and pool where the water accumulates as soon as it rains. The system slows the flow and even stops it, and as the storm passes, it automatically releases the water gradually so that no flooding will occur.”
Two Sides of the Same Coin
Other possible beneficial measures to prevent flooding in agricultural fields are not currently being carried out in Israel. One of them is the planting of natural vegetation to serve as a buffer between agricultural land and nearby streams. “When flooding occurs, the water flows into the buffer zone where the vegetation can slow its spread into the agricultural area, thereby absorbing most of the energy of the flow,” says Egozi. He and his team are currently promoting a pilot for the use of the method in Israel in Nachal Nahalal in collaboration with the Agricultural Research Center of the Volcanic Institute in Neve Ya’ar, the Kishon Drainage and Streams Authority, and the Information Center for Basins, Runoff, and Streams Management.
Creating such a buffer also works in favor of the stream by protecting it from pesticides, fertilizer, and soil grains—substances that can very easily damage its ecosystem. Another way to reduce flood damage to agriculture is to create vegetation strips within the agricultural area itself and increase the density of vegetation cover by sowing crops such as oats, wheat, or clover. Although this method serves as a way to weaken the flow of water running through a farm, it is hardly applied in Israel.
“The creek and the field feed each other,” Egozi says. “If there is a significant land drift in the agricultural field and the stream is blocked as a result, the chance of flooding will increase. These are two sides of the same coin.”
A Worsening Trend
The need to address the problem of flooding in agricultural fields is particularly critical in light of the fact that the phenomenon has become more frequent in recent years than in the past, and it is expected to worsen in the coming years. According to data from Kanat––the Insurance Fund for Natural Risks in Agriculture––25,000 dunams (6,177 acres) of agricultural land flooded in the last three years, and Kanat distributed about NIS 20 million to the affected farmers. In the three years prior to this, a total area of only about 3,500 dunams (864 acres) were flooded, and farmers were accordingly compensated with NIS 3 million.
One clear reason for the flood phenomenon’s intensification is the climate crisis. As the world warms, the amount of water evaporating from oceans, lakes, streams, and soils increases,
and as does the amount of humidity contained in the air, thus causing heavier and more frequent downpour events to occur. “The climate crisis is already hurting Israeli agriculture,” says Shmulik Turgeman, CEO of Kanat. “The various climatic events are becoming more powerful and unpredictable, and the expectation is that the situation will worsen in the coming years.”
Turning to the floods occurring within city boundaries, the acceleration of construction and development in cities are exacerbating the phenomenon of urban runoff because urbanization often means the installation of additional impermeable surfaces like pavements and asphalt roads. “There is no doubt that these are significant processes, which often progress even faster than the effects of climate change,” says Egozi.
“The agreed upon understanding across many institutions, is that certain changes need to be made in order to meet the challenges that are expected in the future, and that efforts must be made to continue the proper maintenance of open agricultural areas,” says Egozi. “Agriculture is very important and so is development, and we need to find ways to balance the different needs.”
According to him, transitioning to greener farming methods is one of the most important steps that can be taken regarding the issue of flood damage to field crops. “Although the percentage of agricultural land shifting towards areas of biodiverse conservation is presently growing, conventional farmland still vastly dominates the majority of agriculture. Instead, the future lies in environmentally sustainable agriculture, which includes the development of cultivation interfaces such that they effectively preserve the soil and the water within it,” he concludes.
This ZAVIT Article was also published in The Jewish Journal on 6 Jan. 2021