Project

Reducing Gambia’s vulnerability to sea level rise and associated impacts of climate change

Gambia Coastal Protection

Following the serious problem with coastal erosion on parts of the Atlantic coastline NIRAS developed a new coastal protection solution.

A wide-ranging coastal protecting programme necessitated by the mounting risk of damage to human and economic activities in the coastal areas of Gambia.

November 5, 2018
  • SDG: #13, #9
  • SECTORS: Infrastructure, Development Consulting
  • COUNTRIES: Gambia
  • CLIENT: The Gambia Government

Following the serious problem with coastal erosion on parts of the Atlantic coastline NIRAS developed a new coastal protection solution to stop the progress of the erosion in Gambia on different sites. Experience from more than 25 years in the country and several assignments in port, coastal protection and water sectors, NIRAS was well aware of the local conditions and technical challenges.

A programme highly linked to climate change

The programme is primarily necessitated by the mounting risk of damage to human and economic activities in the coastal areas of Gambia that is linked to climate change. NIRAS’ solutions are designed to achieve the objective of reducing Gambia’s vulnerability to sea level rise and associated impacts of climate change by improving coastal defences and enhancing adaptive capacities of coastal communities.

The objective is intended to be achieved through the implementation of pilot activities at Kolu, Tanji, Bintang, Illiasa and Tandaba that will lead to the following three outcomes:

  • Component 1: Policies and individual mandates to manage coastal areas strengthened to reduce the risk of climate change
  • Component 2: Vulnerability of coastal investments in climate risks reduced through design construction and maintenance of coastal protection measures
  • Component 3: Rural livelihoods in the coastal zone enhanced and protected from impacts of climate change through the demonstration and transfer of successful coastal adaptation technologies and the introduction of economic diversification.

The present project, which is part of Component 2, will according to the scope of work include installation of offshore breakwaters in combination with revetments supported by light beach nourishment along a 1.5 km long stretch of Kololi beach.

In addition, the work involves stabilisation of the mouth of the Tanji River with revetments protecting Tanji Bridge and the coastal road against erosion.

The project focuses on the long-term durability of the protective means taking into consideration the sea level rise and more rough weather conditions caused by climate change by posing the following question:

What information do we need to ensure the long-term durability of the proposed intervention at Kololi and Tanji?

The project included the detailed design of a coastal protection scheme at Kololi beach (1,000 m) and a stabilisation of the mouth of Tanji river near Tanji Bridge

A part of a more comprehensive programme:

Enhancing Resilience of Vulnerable Coastal Areas and Communities to Climate Change.

The Programme is implemented by National Environment Agency (NEA) on behalf of The Gambia Government in partnership with the UNDP Country Office (CO), which is the GEF implementing Agency for the project.

NIRAS provided the following key services:

  • Project management
  • Surveys
  • Detailed design and cost estimates
  • Stakeholder Workshops and Final reporting
  • Tender documents and assistance on tendering
  • Supervision of Stage 1
  • Project cost: USD 40,000,000

Client: UNDP

 

Phase I: Surveys and Studies

Review of previous and related coastal studies

Surveys:

  • Geotechnical conditions
  • Topographic survey
  • Bathymetric conditions
  • Studies
  • Sediment transport and longshore drift study Hydrographic study

Phase II: Design

Detailed engineering drawings and specifications for proposed protection

  • Detailed construction cost estimate
  • Detailed routine maintenance cost estimate

Phase III: Tendering of Construction of Stage 1 and Supervision

  • Preparation of tender documents for Stage 1 comprising revetment at Kololi and stabilisation at Tanji Bridge.
  • Assistance on contract negotiation and supervision of the implementation of the structures of Stage 1.
Jan Dietrich

Jan Dietrich

Senior Project Manager

+45 4810 4531

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