Nature-based solutions to protect Guyana from coastal flooding

Preventing the loss of vital mangrove forests

Much of Guyana’s population lives below sea level and coastal communities are vulnerable. With climate change causing higher sea water levels, the country has been facing increasingly frequent coastal flooding events. We developed an integrated management system that works with nature to regenerate mangroves and help Guyana combat the flooding. In so doing, we enabled Guyana to protect its coast, businesses and communities more effectively.

Challenge

Restoring Guyana’s coastal defences
Around 90% of Guyana’s population lives in an area that is below sea level, with many inhabiting flood-prone areas along the coast. The coastal plains are also home to about 75% of the country’s economic activities, including almost all of Guyana’s agricultural production. Mangroves protect about 60% of the Guyanese coast from floods, thereby playing a vital role in defending the people and businesses from rising sea levels.

However, over the years, degradation and loss of mangrove forests have resulted in increased coastal flooding and salt water inundation of agricultural land. The salt water inundation could also contaminate Guyana’s freshwater supplies, in addition to have a devastating effect on the country’s agriculture industry. To prevent this, the government has invested heavily in cost-intensive artificial sea defences.

Under the EU’s Global Climate Change Alliance (GCCA), the Guyana Mangrove Restoration Project (GMRP) supports Guyana’s policies on sea defence, climate change and mangrove management. As sea levels continue to rise, the GMRP is examining ways to shield its people and economy and improve flood protection using mangroves.

To assist with this, we seconded one of our experts to help the GMRP address the loss and degradation of mangrove forests. He served as team leader and mangrove specialist, developing an integrated management system to help the Government of Guyana:

Understand what causes the loss of mangroves in the country
Develop a suite of appropriate solutions such as mangrove protection, community interventions, mangrove restoration and coastal engineering
Develop a comprehensive monitoring system to examine the performance of selected interventions

With the National Agriculture Research and Extension Institute (NAREI) – under Guyana’s Ministry of Agriculture – we consulted with stakeholders to agree on priorities in terms of technical assistance for the project. We then worked with GMRP staff to implement project activities.

Solution

Improving mangrove protection
Over the course of the project, we conducted a detailed review of the GMRP’s mangrove restoration efforts. We completed an inventory of mangrove species and the distribution of Guyana’s coastal mangrove ecosystem. We also analysed the mangrove protection and restoration methods, survival rates and sustainability. In addition, we conducted an assessment of the impacts of illegal logging, grazing and infrastructure development on the coastal and estuarine mangrove areas of Guyana.

Based on this information, we helped the GMRP develop and implement a new strategy for rehabilitating mangroves. Previously, Guyana built artificial sea walls to protect the coast. These can be very costly to construct and maintain. As such, we suggested measures designed to increase the recovery of the mangroves along the Guyanese coast, including:

Introducing alternative restoration methodologies, such as planting coastal grass species
Constructing fences to control grazing
Hydrologic restoration

This would ensure the protection and conservation of the mangroves, providing protection for the coast in less time and at a lower cost than sea walls.

We also assisted with the development of a GIS-based monitoring and mapping system. To achieve a harmonised monitoring system for the coastal zone, we also helped integrate the mangrove monitoring with:

Sea defence monitoring
Monitoring, reporting and verification of forests under Reduced Emissions from Forest Deforestation and Degradation (REDD+) scheme. REDD+ allows countries to generate carbon credits from forest areas that are protected from degradation or cutting

We also conducted a biodiversity assessment of mangrove sites. This can be used as a baseline for future assessments and as the basis for future management plans for these areas.

During the course of the test campaign, modifications were introduced to the layout of the interior of the pump chamber to improve the hydraulic performance. This included baffle columns, which is vertical columns that slow down the flow and dissipate energy as water enters the pump chamber. Here, a calm and well distributed flow is achieved in the pump chamber, which ensured that all evaluation parameters were well within the acceptable limits according to international guidelines.

For this project, we made use of our expertise within physical scale model tests of hydraulic structures and pumping stations. At our model test facilities, we perform tests with pumping stations in a dedicated test bench, making sure all equipment is in place for a full hydraulic assessment. Thus, forming the basis for verification against relevant standards. In addition to physical model tests, we also have the expertise to perform detailed numerical CFD simulations of pumping stations, which is often a valuable approach in combination with physical model tests.

Results

Nature-based integrated management system re-establishes mangroves along the coast of Guyana, leading to improved flood protection and coastal resilience

About the client

Government of Guyana and the European Union (EU)

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