Writte by Baltazar Montemor
Translated by Francisco Chuquela
It is known that saline intrusion is a reality, but the dimension of the phenomenon is unknown. The approaches are based on estimates, often by default, with some significant empiricism burden.
In the Xai-Xai zone, when the tide is high (high tide), a marked rise in water is clearly noticeable due to the penetration of the sea. This has no solution because it is a natural phenomenon. What we can do is find ways to mitigate impacts through both structural and non-structural measures. The dam building in the Mapai region, for example, may contribute more and more to pushing the salt wedge, but there may also be measures that go through the construction of defense dikes.
Although the magnitude of saline intrusion affecting Mozambican rivers is unknown, the phenomenon is significant and represents a problem to be taken into account. Actions are taken that take into account the perspective of mitigating the effects of saline intrusion. These actions should include the way in which reservoirs are managed in relation to the amount of water released to meet the demand, taking into account this delicate environmental phenomenon which threatens to engulf us.
It is recognized the country’s international efforts to find ways of guaranteeing an ecological flow with the countries with which it shares rivers, with the ultimate goal of containing salt-water intrusion. Studies carried out in partnership with South Africa, Swatini, former Swaziland and Zimbabwe already indicate the need to make a water reserve, first for ecological flows, second to contain saline intrusion.
It is exemplified by an agreement between Mozambique, South Africa and eSwatini (Incomat and Maputo Agreement), which establishes a specific basin water reserve for environmental issues.
As the magnitude of saline intrusion is not known, the speed of the phenomenon is not known either. It is only estimated that saline intrusion carries a considerable speed, to the despair of thousands of affected. There is a certain progression of the salt wedge, which can not be denied. Concrete situations can be mentioned, for example, from the Maputo River, where saline intrusion has already reached the Salamanga region, with a progressive increase in salt levels, resulting of the progression of the salt wedge to the interior.
The Mabalane District in Gaza is one of the extensive regions of the country crossed by the Limpopo River. At times, communities explored the river’s casualties, where they harvested considerable amounts of different agricultural products for family consumption and some surplus for sale, generating income to cover the rest of the needs, such as the acquisition of manufactured goods, health, education.
The effect of saline intrusion and salinization has transformed this potential into arid terrain. The communities were forced to change the Limpopo lowlands with high rainfed areas. Here the dependence on nature (rain) is quite strong, with production levels and productivity quite low.
“Now we are very hungry here in Mabalane District, because this year it rained only once. The seeds that had been thrown to the ground germinated, but they “burned” all, said Rosa Jorge Maphosse. This Mabalane villager regrets the fact that communities have grown from large food producers in the Limpopo valley to shoppers because they are no longer able to produce. “We buy flour and other products in Chókwè”.
Due to low production and agricultural productivity as a result of saline intrusion and salinization of Limpopo valley soils, many producers have been forced to switch agriculture with coal production, another source of environmental damage, through deforestation. Rosa Jorge Maphosse says that she also started producing coal that she sells in Maputo city.
Almost the entire northern province of Gaza has high levels of forest destruction as a result of the massive production of charcoal for commercial purposes, with the urban environment being the largest consumer market. “With this coal business I can do anything,” says Rosa Jorge Maphosse.
Like the Limpopo casualties, which lost production capacity due to saline intrusion and salinization, the Incomati basin is also affected by the phenomenon. João Palate, from the Union of Agricultural Cooperatives in Marracuene, said that the area that the producers failed to explore was extensive. More than five thousand producers are affected. “We have a large part, from the area of Macaneta, so far, where there is no longer anything! It is not possible to produce, because there was a lot of salinity and the terrains are affected “, laments Palate.
Before Marracuene, the Rio Incomáti crosses the region of Moamba. There are also areas affected by salinization. Joshua Sithoi, president of the Moamba Irrigation Peasants Association, said that the association was forced to stop exploring a considerable portion because it was affected. “We have about 85 hectares that are submerged in pockets of salinization.”
The solution to the problem is identified, but there is no capacity locally. “We need to revive or rehabilitate the drainage channels because they are totally blocked. They are channels that require the intervention of heavy machinery that we do not have. We tried manually, but we did not go far. The situation worsened with the floods of 2000. As you know, an irrigation system to operate in full must, every five years, undergo some maintenance intervention or small rehabilitation. However, it is more than 30 years that our irrigation does not benefit from any intervention required,” laments Joshua Sithoi. (to be continued)