Saltwater intrusion: A looming threat to island communities' food security

Dar es Salaam. Communities living on islands are at risk of food insecurity due to saltwater intrusion's detrimental effects on agricultural output, particularly an alarming reduction of arable land.

Defined as the movement of saline water into freshwater aquifers, saltwater intrusion can lead to groundwater quality degradation, including drinking water sources.

Human activities, notably the felling of mangrove trees for timber, fuel, and other purposes, exacerbate its detrimental effects. The expansion of farms, driven by the misguided belief in higher yields from cleared areas, further worsens the problem.

During a recent visit to the Mafia, Unguja, and Pemba islands, The Citizen witnessed the alarming impact of seawater intrusion, which calls for immediate action.

The visit revealed stark evidence of its devastation, particularly in areas like the valley between Kibada and Kungwi villages in Baleni Ward, in the Northern Division of Mafia Island, where rice cultivation has been severely affected.

The governments and climate stakeholders must collaborate on implementing adaptation measures to ensure the sustainable livelihoods of island residents. Failure to act decisively could worsen food insecurity and amplify the plight of vulnerable communities.

Mr Mussa Mahadhi, a farmer, told The Citizen that saltwater has adversely affected rice production in the area following the salinisation of a large part of agricultural land.

“Arable land has greatly reduced, resulting in dismal annual yields,” he said.

Highlighting the severity of the situation, the Northern Division Executive Officer, Mr Paul Kiyeyeu, said that over 20 percent of fertile agricultural land has been engulfed by salt water.

“Agricultural activities in this area could come to an end, leading surrounding villages into a crisis of freshwater scarcity if immediate intervention measures are not taken,” he warned.

Mr Kiyeyeu fears that farmers might be forced to relocate or change farming methods to avoid the looming threat of food insecurity. He urged environmental institutions to step in promptly to aid farmers in averting further damage.

Mr Ally Masika, a resident of Kiongwe Kidogo in Zanzibar’s Unguja North Region, said farmers’ efforts to combat saltwater intrusion haven’t borne the anticipated results.

Despite the repeated construction of protective ridges, the relentless advance of seawater has rendered their defences futile. "The daily escalation in seawater intensity has rendered our defences inadequate," he shared.

According to Mr Masika, agricultural land has been diminishing by the day, forcing the worst-affected citizens to abandon their farms entirely, leading to food shortages.

Mr Masika’s concern was echoed by a colleague, Mr Rashid Makame Nchinji, who said the project to construct a wall to prevent saltwater intrusion has stalled and that the citizens have been left in the dark regarding the matter.

“No information has been issued so far, leaving farmers with suspicions. This is not right because the impact, especially food insecurity, has been gradually increasing,” he lamented.

The Mafufuni local government leader, Mr Mahadhi Mjumbe Haji, said many farmers have been displaced by saltwater intrusion from the area co-shared with their Kiongwe Kidogo counterparts.

“The situation has worsened in recent days due to the effects of both climate change and human activities. The construction of ridges to prevent saltwater intrusion has so far proved futile,” he noted.

At the Tondooni basin, in Mkoani District, South Pemba Region, Mr Mohamed Fakhi shares that there was a time when germinated rice seedlings dried due to salt water.

“The same thing happened when I replanted the seeds. I have repeatedly done so in vain,” he sadly shared.

Ms Faraja Mussa Makame, blames mangrove tree cutting for the dwindling crop yields in the basin. She calls upon authorities to consider introducing adaptation measures to reduce the impact and restore crop yields in the area.

Her sentiment was seconded by Ms Mtumwa Abdallah Mohamed, who said she used to harvest 10 bags of rice per acre in the past, an amount that has since declined to only one bag.

“This decline is subject to the decline in the size of cultivable land. We are forced to continue farming in these small areas because we have nowhere else to go. The government should come up with impactful corrective measures,” she pleaded.

For her part, Ms Fatuma Hamisi Salum said that despite their investments in agriculture in terms of labour, seeds, and fertiliser, harvests have been relatively low and worrying.

“The government and all stakeholders should support farmers by preventing saltwater intrusion from causing any further damage. They should help us so we can continue with our farming activities like we did before,” pleaded Ms Salum.

Human activities

Commenting on mangrove tree felling, Mafufuni local government leader, Mr Haji, said incidents of farm expansions and sand mining are on the increase in the area.

Unfortunately, the perpetrators never receive the appropriate punishment that might act as a deterrent to others. Mr Haji suggested that laws and regulations be sufficiently severe to deter offenders.

The Kiongwe Kidogo resident in Unguja North Region, Mr Ally Masika, said the community has been mobilised to engage in mangrove tree planting to restore the lost vegetation cover. Also, the local government authority patrols the area to apprehend those who cut down trees.

Mr Rashid Makame Nchinji suggested that patrols should be intensified to control mangrove felling and that the culprits should be handed over to the judicial organs for the law to take its course.

Mr Makame said sand mining and farm expansions have been escalating saltwater intrusion trends in Pemba.

“While trees are cut for timber, firewood, and charcoal, farm expansion has also been depleting the vegetation cover. Sand mining is worsening the situation,” he said, calling on the government to quickly intervene.

Government initiatives

The environment director in Zanzibar’s First Vice President’s Office, Ms Farhat Ali Mbarouk, said her office conducted a study in 2019 to establish the impact of beach erosion, saltwater intrusion, and sea inundation in Unguja and Pemba.

The study, funded by the United Nations Development Programme, aimed to help the government come up with adaptation measures.

The areas surveyed in Unguja included Nungwi, Makoba, Mto wa Pwani, Kombeni, Pete, Michamvi, Pingwe, Michami Kae, Jambiani, Kikadini, and Jambiani Kibigija.

In Pemba, Msuka Mashariki, Majenzi, Gando, Wingwi, Kangani, Mjimbini, Wambaa, and Kisiwa Panza areas were surveyed.

The findings showed that the Nungwi, Mkokotoni, Bumbwini, Michanvi Kae, Michanvi Pingwe, Michanvi, Kisakasaka, Pete-Jozani, and Jambiani areas were severely affected by beach erosion and saltwater intrusion.

In Pemba, the affected areas were Msuka, Gando, Micheweni, Wingwi, Tovuni, Kwa Kingoji, Kwa Vunde, Kwa Tumbo, Wambaa, Kangani, Kwa Sharifu, Wakuungwe, Maotwe, and Kisiwa Panza.

According to Ms Mbarouk, a three-year climate change adaptation initiative is expected to take off next year in Kiongwe Kidogo.

“The ridge construction is among the projects slated to be implemented through the $1 million (Sh2.5 billion) project. Other activities include the construction of reservoirs, public education, and alternative livelihoods,” she said. The project will also be implemented in other affected areas.

According to Ms Mbarouk, most of these projects will be implemented in Pemba, which is mostly affected due to its geographical location.

The assistant environment director, Mr Mwalim Khamis Mwalim, said the department has embarked on a survey to establish the severely affected areas and the types of effects such as human settlement, income generation activities, and food production, after which it will suggest appropriate intervention measures.

“The findings will be used to establish a database that will ease access to climate change-related information. This information will enable the government to prepare climate change mitigation project write-ups to be used by various stakeholders.

Furthermore, Ms Mbarouk said the government has signed an agreement with Global Network Company to conduct a climate vulnerability assessment on the island after a similar assessment was conducted in the Jambiani Area under donors’ funding.

“Climate issues are sensitive on the island, and water authorities have also reported fresh, clean, and safe water turning saline due to escalating incidents of seawater intrusion,” she said, terming saltwater intrusion as a real challenge in Zanzibar.

According to Ms Mbarouk, the government is now requiring residents to participate in alternative livelihood schemes designed to lessen the strain of environmental deterioration in areas that are badly impacted.

The ecosystem-based adaptation project for rural resilience, which is being implemented in Zanzibar’s North Unguja and Mainland Tanzania, aims to provide citizens with alternative livelihood methods.

“Currently, citizens are provided with fishing boats as an alternative to engagement in environmental degradation activities. Women are trained in entrepreneurial activities such as handcraft and hairdressing, among others,” she said.

The environment department has also come up with the Green Legacy Initiative, to be launched next month, to adopt climate resilience through increased community involvement.

Both the public and private sectors and CSOs will be involved in the execution of adaptation programmes such as tree planting to reinstate the vegetation cover depleted by climate change on the island.

The department is currently mobilising citizens to engage in carbon trading. Ms Mbarouk said since saltwater intrusion affects crop production, it puts the island at serious risk of food insecurity.

Meanwhile, the environment department in the Vice President's Office of the Union government could not provide insights into mitigation projects and plans to protect islands on the Tanzanian mainland from climate change effects, especially salt intrusion as witnessed in Mafia.

This article is supported by the Bill & Melinda Gates Foundation.