Ghana’s coast: where the sea could reach today and by 2050
At the 1-in-100-year sea level, about 132 km² of low ground along Ghana’s coast is connected to the sea today. With a 0.25 m sea-level rise scenario for 2050, that grows to about 182 km². Most of it lies around Ada and the Volta estuary. This is a screening of where water could reach, not a 2D flood model.
- 8 coastal districts with 3 km² or more connected to the sea in 2050
How to read this: the outlined districts hold most of the low ground the 1-in-100-year sea could reach with 0.25 m of sea-level rise, from Ahanta West in the west to Ada East at the Volta mouth. Static screening with provisional forcing.
- sections of coast, each about 10 km, each with 32 years of hourly sea levels
- 57
- the highest 1-in-100-year sea level of the 57 sections, tide, surge and waves together, above model mean sea level (the lowest is 1.06 m)
- 1.20m
- of low ground connected to the sea at that level today
- 132.3km²
- with a 0.25 m sea-level rise scenario for 2050
- 182.4km²
Is Ghana’s coast at risk from sea-level rise?
Yes, where the land behind the beach is low. At the 1-in-100-year sea level, about 132 km² of low ground is connected to the sea today. Adding 0.25 m of sea-level rise for 2050 raises that to about 182 km², more than a third more. The lagoons and deltas around Ada and the Volta estuary hold most of it.
I raised the extreme sea level over a 30 m terrain model and kept only the low ground water could reach from the sea, one neighbouring cell at a time. A lagoon basin behind a high sand bar stays dry unless a path connects it.
That rule matters. A simple “bathtub” that floods every low spot would put 709.8 km² under water today, more than five times as much, much of it lagoon basins the sea cannot reach at that level.
Along most of the coast the extreme sea level itself barely changes, by little more than a tenth of a metre. What changes is the ground behind it. Steeper stretches shrug off a level that floods a lagoon edge.
The sea level barely varies along the coast; the low ground it reaches varies a lot
How to read this: the coast runs west to east, Half Assini to Aflao. Top: the 1-in-100-year sea level in each 10 km section. Bottom: the low ground connected to the sea there. Switch to 2050 or the stress test, and tap the chart, or use the arrow keys, to move along the coast.
Static connected inundation at 30 m. Levels are relative to the tide-and-surge model’s mean sea level, with no local datum correction. Forcing is provisional.
Sources
My analysis (2026), independent consultancy, separate from my dissertation. Water levels: GTSM hourly reanalysis; waves: ERA5 (Copernicus Climate Change Service). Terrain: FABDEM v1-2 (Fathom and University of Bristol, CC BY-NC-SA 4.0).
| Scenario | Sea level added | Low ground connected to the sea at 1 in 100 years, km² |
|---|---|---|
| Today | 0 m | 132.3 |
| 2050 | +0.25 m | 182.4 |
| Stress test | +0.75 m (0.25 m sea-level rise + 0.5 m wave stress test) | 963.8 |
How high can the sea reach on Ghana’s coast?
Once in 100 years on average, about 1.06 to 1.20 m above the model’s mean sea level, depending on the stretch of coast. That counts the tide, the storm surge and the wave setup that breaking waves pile against the beach. Wave setup alone adds 0.09 to 0.16 m.
For each of 57 sections I built an hourly record from 1993 to 2024: tide and surge from a global model, plus wave setup worked out hour by hour from wave data. Then I fitted an extreme-value curve to the storm peaks.
Before trusting the model, I checked it against the tide gauge at Takoradi. Hour by hour they matched closely, with a correlation of 0.94 and a typical error of 0.135 m. In the biggest storms the model ran about 0.17 m low, so the true extremes may be a little higher.
The nine steps, from the Takoradi gauge to the 30 m maps: how the coastal screen works.
Which coastal districts flood first?
Ada East and Ada West, around the Songor lagoon and the Volta estuary, hold about 85 km² of the 132 km² connected to the sea today, nearly two-thirds. The Densu delta at Weija Gbawe comes next with about 16 km². With the +0.25 m scenario for 2050, Ada East grows from 45 km² to 77 km². derived from the model
The shares are my own sums of the district results derived from the model. Ada East and Ada West hold 64% of the connected area today and 65% in 2050.
Some smaller places change faster. Shama, at the Pra estuary, goes from about 1.5 km² to 6.7 km², more than four times as much. Tema Metropolitan goes from 0.1 km² to 2.0 km²: a quarter of a metre connects low ground there that stays dry today.
Several of these districts are also Act districts for river flooding: Ada East, Ada West, Weija Gbawe, Shama and Ningo/Prampram. Where river and sea flooding meet, a local study needs both.
Ada holds most of the connected low ground, today and in 2050
How to read this: each bar is one district’s low ground connected to the sea at the 1-in-100-year level, in km². Switch between today and 2050 to see which districts grow.
Static connected inundation at 30 m; districts with 3 km² or more in 2050.
| District | Region | Today, km² | 2050, +0.25 m, km² | Stress test, +0.75 m, km² | River flood class |
|---|---|---|---|---|---|
| Ada East | Greater Accra | 45.13 | 77.08 | 133.63 | Act |
| Ada West | Greater Accra | 39.42 | 41.95 | 47.67 | Act |
| Weija Gbawe | Greater Accra | 15.94 | 18.66 | 22.94 | Act |
| Ekumfi | Central | 7.15 | 8.15 | 10.05 | Monitor |
| Shama | Western | 1.46 | 6.74 | 15.19 | Act |
| Ahanta West | Western | 4.00 | 4.36 | 5.49 | Monitor |
| Gomoa Central | Central | 3.58 | 4.20 | 5.26 | Monitor |
| Ningo/Prampram | Greater Accra | 2.51 | 3.28 | 5.93 | Act |
Also between 2 and 3 km² in 2050: Komenda-Edina-Eguafo-Abirem, Effutu and Tema Metropolitan. The river and sea together on the lower Volta: lower Volta flood risk.
What happens in the stress test?
The connected area jumps to about 964 km², over five times the 2050 figure. The stress test adds a further 0.5 m on top of the 2050 scenario, 0.75 m above today, as a check on wave processes. At that level the Keta lagoon connects to the sea: Keta and Anloga alone account for about 547 km². derived from the model
It is a sensitivity test, not a forecast or a design scenario. It asks how sensitive the answer is to a higher water level from wave processes the screen simplifies; it does not model overtopping. The answer is: very sensitive, in one place. The Keta lagoon is low and wide, and once water finds a way in, a static model floods all of it.
Part of the stress-test flooding runs far up the Volta channel. That is partly an artefact of the static method, which lets water travel along any connected low ground however long the path.
Is coastal flooding the same as coastal erosion?
No. Flooding is the sea rising over low ground for a few hours or days. Erosion is the shoreline itself moving or breaking through. My screen holds the shoreline fixed, so it does not show erosion, breaches, wave run-up or overtopping, all of which can change where the sea gets in.
Fuveme, on the sand bar between the Keta lagoon and the sea, shows why the two meet. In April 2026 the Ghana News Agency reported tidal waves breaking through there, and concern that the sea could cut a second estuary into the lagoon. A breach like that would change which land is connected to the sea, which is exactly what a static screen cannot predict.
That is one reason the next stage at Keta is a 2D model with surveyed sand bars, inlets and defences.
Is this a 2D coastal flood model?
No. It is a static screening of the low ground connected to the sea, with provisional forcing. Its job is to find the places that deserve a full 2D model: the Keta lagoon, the Songor lagoon at Ada and the Densu delta at Weija. No 2D coastal model has been run for Ghana yet; that is the next stage.
A 2D model at those sites would use the same hourly tide, surge and waves as boundary conditions, at 10–30 m, with surveyed defences, lagoon inlets and drains. TUFLOW and SFINCS are two tools that can do it. It would show how fast water arrives and how long it stays, which a warning service and a design team both need.
My own 2D modelling experience is on rivers. At Hamstall Ridware in England I built a linked 1D–2D river model jointly with an Environment Agency modelling colleague, after doing the hydrology myself.
Where does the 2050 sea level come from?
It is one screening scenario: 0.25 m of sea-level rise by 2050, added to today’s extreme levels. It shows which places are sensitive to a modest rise. It is not a design standard; a design study would take its allowance from current sea-level projections for Ghana’s coast and test a range of them.
What are the limits of the coastal screen?
Provisional forcingAll 57 sections’ links to the tide and wave models are provisional and await review; 43 are flagged because the nearest model point is more than 15 km away.
No common datumThe model’s mean sea level, the tide-gauge zero and the terrain’s datum have not been reconciled, so absolute levels carry an offset uncertainty.
Static, not hydrodynamicNo flow, timing, overtopping, run-up, breaching or drainage. Connectivity along the Volta channel under the stress test is partly an artefact.
Hazard onlyCoastal exposure and damage have not been finalised and are not shown here.
Terrain licenceFABDEM 30 m (CC BY-NC-SA 4.0), shown partially and for illustration, with the owner’s agreement. Commercial use needs a FABDEM licence.
Not officialIndependent consultancy, separate from my dissertation. Not official figures of the Government of Ghana or the World Bank.
Questions people ask
Will Accra flood from the sea by 2050?
In this screen, very little of central Accra: districts such as Krowor and La Dade-Kotopon have under 0.1 km² connected to the sea even with +0.25 m of sea-level rise by 2050. Accra’s floods mostly come from rain and drains. The Densu delta at Weija and parts of Tema are the coastal exceptions near the city.
How many people live where the sea could reach?
Those figures are not published yet. The screen maps where the sea could reach; its counts of people and damage come from a preliminary run and are not published.
What is a 1-in-100-year sea level?
A sea level with a 1% chance of being reached or exceeded in any year. Here it combines the tide, the storm surge and the wave setup at the shore.
Can I see the flood maps?
Three illustrative windows are on the Ghana coast case study: Accra from Weija to Tema; Ada, the Volta estuary and the Keta lagoon; and Shama and the Pra estuary. The full national map is not published, under the terrain data’s licence.
Is this part of your Oxford dissertation?
No. The river flood work was also my Oxford MSc dissertation; the coastal screen is separate independent consultancy and was not part of the examined dissertation.
Sources
- Nuhu, H. (2026). Ghana national coastal flood hazard: total water level, extreme-value analysis and connected inundation. Independent consultancy. Method and results.
- Copernicus Climate Change Service. Global sea level change time series from 1950 to 2050, including hourly tide and storm surge levels from the Global Tide and Surge Model (GTSM). Climate Data Store.
- Copernicus Climate Change Service. ERA5 hourly data on single levels (waves). Climate Data Store.
- University of Hawaii Sea Level Center. Takoradi tide gauge, research-quality hourly data. UHSLC.
- Fathom and University of Bristol. FABDEM v1-2, 30 m terrain with forests and buildings removed (CC BY-NC-SA 4.0). Data record.
- Muis, S. et al. (2020). A high-resolution global dataset of extreme sea levels, tides, and storm surges, including future projections. Frontiers in Marine Science 7, 263. doi:10.3389/fmars.2020.00263.
- Ghana Statistical Service / OCHA. Ghana subnational administrative boundaries (COD-AB). Humanitarian Data Exchange.
- Ghana News Agency (29 April 2026). President Mahama visits tidal waves hit Fuveme in Volta Region. Article.
Work with me
Planning work on a lagoon, an estuary or a stretch of coast?
I can estimate extreme sea levels with their uncertainty, screen where the sea could reach today and with sea-level rise, and scope the 2D modelling for the sites that need it. Remote or in-country.