Jump to content
Toggle search
Toggle menu
  • 50 articles
  • 63 files
  • 3 users
  • 437 edits
Pwani 2050 Commons
Toggle preferences menu
Toggle personal menu
Not logged in
Your IP address will be publicly visible if you make any edits.

Tudor Creek Barrage: Difference between revisions

From Pwani 2050 Commons
More actions
[checked revision][checked revision]
VisualWikitext
New project page for Tudor Creek Barrage, with sources, uploaded documents and counterpoints
 
Express the energy estimate as a share of Mombasa use, per Jay
 
Line 18: Line 18:
}}
}}


The '''Tudor Creek Barrage''' is a project within the [[Energy]] theme. It is a proposal from the Pwani 2050 plan to close the mouth of Tudor Creek in [[Mombasa County]] with a barrage about 650 m long and 30 m wide, running from Fort Jesus on Mombasa Island to English Point on the Nyali shore. The barrage would carry a walking and cycling park on top, a four-lane road tunnel inside to relieve the Nyali Bridge, and tidal turbines with batteries below, which the plan says could supply 75 per cent of Mombasa's electricity. The plan cites Singapore's Marina Barrage as a model. It is a concept only: no study, budget or sponsor exists. A first check of the energy claim against published tidal data, set out below, suggests the turbines would supply a few per cent of the coast's electricity rather than three quarters of Mombasa's, and the southern landing would fall inside the Fort Jesus World Heritage property.
The '''Tudor Creek Barrage''' is a project within the [[Energy]] theme. It is a proposal from the Pwani 2050 plan to close the mouth of Tudor Creek in [[Mombasa County]] with a barrage about 650 m long and 30 m wide, running from Fort Jesus on Mombasa Island to English Point on the Nyali shore. The barrage would carry a walking and cycling park on top, a four-lane road tunnel inside to relieve the Nyali Bridge, and tidal turbines with batteries below, which the plan says could supply 75 per cent of Mombasa's electricity. The plan cites Singapore's Marina Barrage as a model. It is a concept only: no study, budget or sponsor exists. A first estimate from published tidal data, set out below, puts the turbines' output at roughly 3 to 10 per cent of Mombasa's electricity use, so reaching the plan's 75 per cent would need a much larger basin or additional generation; the southern landing would also fall inside the Fort Jesus World Heritage property.


== What it is ==
== What it is ==
Line 33: Line 33:
A rough estimate, calculated for this page from the standard formula (energy per tide of half the water density times gravity times basin area times range squared) and the KMFRI figures above, gives the following. Taking an average basin of about 14 km² and averaging the square of the range across spring and neap tides, the theoretical maximum is about 100 GWh a year. La Rance captures about 35 per cent of its own theoretical maximum, which would give Tudor Creek about 35 GWh a year, an average output of about 4 MW. Even the most generous case, the full high-water basin at the spring range all year round, gives about 95 GWh a year at La Rance's capture rate. These are order-of-magnitude figures, not a design.
A rough estimate, calculated for this page from the standard formula (energy per tide of half the water density times gravity times basin area times range squared) and the KMFRI figures above, gives the following. Taking an average basin of about 14 km² and averaging the square of the range across spring and neap tides, the theoretical maximum is about 100 GWh a year. La Rance captures about 35 per cent of its own theoretical maximum, which would give Tudor Creek about 35 GWh a year, an average output of about 4 MW. Even the most generous case, the full high-water basin at the spring range all year round, gives about 95 GWh a year at La Rance's capture rate. These are order-of-magnitude figures, not a design.


For comparison, the whole Coast region, of which Mombasa is the largest consumer, used 2,087.62 GWh of electricity in the year to June 2026.<ref name="standard-epra">[https://www.standardmedia.co.ke/business/article/2001559029/nairobi-mombasa-and-north-eastern-major-electricity-consumers Nairobi, Mombasa and North Eastern major electricity consumers], Patrick Vidija, The Standard, 30 September 2026.</ref> On these estimates the turbines would supply roughly 2 to 5 per cent of the coast's electricity. Supplying 75 per cent of Mombasa's would need a basin roughly ten times larger or a much greater tidal range than Tudor Creek has. Batteries can shift the output to the evening peak but cannot add to it.
Mombasa's own electricity use is not published separately; the Coast region as a whole used 2,087.62 GWh in the year to June 2026.<ref name="standard-epra">[https://www.standardmedia.co.ke/business/article/2001559029/nairobi-mombasa-and-north-eastern-major-electricity-consumers Nairobi, Mombasa and North Eastern major electricity consumers], Patrick Vidija, The Standard, 30 September 2026.</ref> Assuming Mombasa, the region's largest city and industrial centre, accounts for half to two-thirds of that, about 1,000 to 1,400 GWh a year, the barrage's estimated 35 to 95 GWh would meet roughly 3 to 10 per cent of Mombasa's needs (calculated on this page). Meeting the plan's 75 per cent, about 750 to 1,050 GWh, would need a basin roughly ten times larger or a much greater tidal range than Tudor Creek has, so the energy element would work best alongside other sources. Batteries can shift the output to the evening peak but cannot add to it.


== Rationale ==
== Rationale ==

Latest revision as of 07:46, 16 October 2026

AI-generated concept illustration of a low barrage with arched piers across the mouth of Tudor Creek at sunset, with a landscaped park and a glazed walkway on top, dhows on the water and Fort Jesus and Mombasa Old Town on the far shore
Tudor Creek Barrage (Fort Jesus to English Point)
Project
Statusproposed
ThemeEnergy
PillarInfrastructure
CountiesMombasa
Lead organisationPwani 2050
Funding sourceNot yet identified

The Tudor Creek Barrage is a project within the Energy theme. It is a proposal from the Pwani 2050 plan to close the mouth of Tudor Creek in Mombasa County with a barrage about 650 m long and 30 m wide, running from Fort Jesus on Mombasa Island to English Point on the Nyali shore. The barrage would carry a walking and cycling park on top, a four-lane road tunnel inside to relieve the Nyali Bridge, and tidal turbines with batteries below, which the plan says could supply 75 per cent of Mombasa's electricity. The plan cites Singapore's Marina Barrage as a model. It is a concept only: no study, budget or sponsor exists. A first estimate from published tidal data, set out below, puts the turbines' output at roughly 3 to 10 per cent of Mombasa's electricity use, so reaching the plan's 75 per cent would need a much larger basin or additional generation; the southern landing would also fall inside the Fort Jesus World Heritage property.

What it is

Tudor Creek bounds Mombasa Island on the north-west and runs about 10 km inland. A Kenya Marine and Fisheries Research Institute (KMFRI) study describes a single narrow, winding inlet with a mean depth of 20 m that opens into a shallow central basin of 6.37 km² at low spring tide and 22.35 km² at high spring tide, fringed by about 8 km² of mangrove forest. It gives the spring tidal range as 3.5 m and the neap range as 1.1 to 1.3 m.[1] The Kenya Ports Authority gives Mombasa's mean high water springs as 3.5 m and its highest astronomical tide as 4.1 m above chart datum.[2]

The proposal combines three functions in one structure. The road tunnel would offer a second crossing of the creek beside the Nyali Bridge, a six-lane bridge of about 392 m opened in 1980 that needed major structural repairs in 2005.[3] The park on top would follow the Marina Barrage in Singapore, whose green roof is used for events and kite flying.[4] The turbines would generate electricity from the tide flowing in and out of the creek, as the barrages at La Rance in France and Sihwa Lake in South Korea do.

The Singapore model

The Marina Barrage opened on 31 October 2008 across the 350 m mouth of the Marina Channel, at a cost of S$226 million for the structure. It serves flood control, water supply and recreation: nine crest gates and seven pumps keep the sea out and turn Marina Basin into a freshwater reservoir fed by a 10,000 ha urban catchment.[5][4] It generates no tidal power. A tidal power barrage works the other way, by letting the sea in and out through turbines, so the parts of the Singapore model that transfer to Tudor Creek are the park on top and the gate engineering, not its purpose.

Testing the energy claim

The energy a tidal barrage can capture grows with the area of the basin behind it and with the square of the tidal range. La Rance, with a basin of 22.5 km², about the same as Tudor Creek at high water, has an average range of about 8 m and produces about 500 to 600 GWh a year from 240 MW of turbines.[6][7] Tudor Creek's range is less than half of La Rance's.[1]

A rough estimate, calculated for this page from the standard formula (energy per tide of half the water density times gravity times basin area times range squared) and the KMFRI figures above, gives the following. Taking an average basin of about 14 km² and averaging the square of the range across spring and neap tides, the theoretical maximum is about 100 GWh a year. La Rance captures about 35 per cent of its own theoretical maximum, which would give Tudor Creek about 35 GWh a year, an average output of about 4 MW. Even the most generous case, the full high-water basin at the spring range all year round, gives about 95 GWh a year at La Rance's capture rate. These are order-of-magnitude figures, not a design.

Mombasa's own electricity use is not published separately; the Coast region as a whole used 2,087.62 GWh in the year to June 2026.[8] Assuming Mombasa, the region's largest city and industrial centre, accounts for half to two-thirds of that, about 1,000 to 1,400 GWh a year, the barrage's estimated 35 to 95 GWh would meet roughly 3 to 10 per cent of Mombasa's needs (calculated on this page). Meeting the plan's 75 per cent, about 750 to 1,050 GWh, would need a basin roughly ten times larger or a much greater tidal range than Tudor Creek has, so the energy element would work best alongside other sources. Batteries can shift the output to the evening peak but cannot add to it.

Rationale

The plan's case is that one structure could relieve traffic on the Nyali Bridge, give the city a new public waterfront park and generate clean power. The traffic pressure is real: a second Nyali bridge of about 520 m, 500 m east of the present one, was being planned in 2018, when the existing bridge was about 38 years old and the county said at least 70 per cent of vehicles heading for the city centre came from Links Road.[9] The county's current plan still lists a "Nyali second Bridge" among the projects envisaged by the Mombasa Gate City Master Plan.[10] A 2021 review from the Technical University of Mombasa suggested that tidal barrages "can be very useful, especially in creeks along the Kenya coast, such as Mida, Kilifi, Tudor and Mtwapa creeks", while warning of their potential to harm plants and animals.[11]

Status and timeline

The barrage exists only as a proposal in the Pwani 2050 plan. No feasibility study, environmental assessment, heritage impact assessment or official proposal for a barrage, tunnel or tidal plant at the mouth of Tudor Creek has been found. No government tidal resource assessment for the creek has been published. The second Nyali bridge has no reported progress since about 2020.

How the project would be procured

There is no Terms of Reference or budget. A structure combining a national road crossing, a power plant and a World Heritage setting would involve the Kenya National Highways Authority or Kenya Urban Roads Authority, the energy regulator, the National Museums of Kenya and the National Environment Management Authority, and could only proceed after a heritage impact assessment reviewed by the UNESCO World Heritage Centre (see below).

Who is involved

The proposal comes from the Pwani 2050 plan. The County Government of Mombasa plans the city's crossings and waterfront.[10] The National Museums of Kenya manages Fort Jesus. The Kenya Ports Authority publishes the tidal data,[2] and KMFRI has studied the creek's hydrography and mangroves.[1]

Concerns and counterpoints

No one has commented in public on this proposal. The points below come from the official record on the site and from experience with tidal barrages elsewhere.

Heritage

ICOMOS's 2011 evaluation of Fort Jesus for the World Heritage List records that the property and its buffer zone were "expanded to include part of the seawaters in front of Fort Jesus and Mombasa Old Town", and that the property includes underwater archaeological remains; it named "possible future development pressures on the urban buffer zone and the erosion of the Fort's coral rock foundations" as the two main threats.[12] Kenya's nomination places the wreck of the Portuguese frigate Santo Antonio de Tanna, sunk in 1698, "just at the entrance to old Port", protected by gazette notice since 1977.[13] A barrage landing at the Fort would sit within the protected setting and would change the tidal currents at the Fort's foundations, for better or worse. UNESCO has acted against large crossings at other sites: Germany's Dresden Elbe Valley was removed from the World Heritage List in 2009 over a four-lane bridge,[14] and for Kenya's own Lamu Old Town the World Heritage Committee has repeatedly asked for heritage impact assessments of LAPSSET development.[15]

Water quality, mangroves and fish

Tudor Creek is already under strain. It lost 86.9 per cent of its mangrove forest between 1992 and 2009, the highest rate recorded in Kenya.[16] Raw sewage from Mikindani, Tudor and Old Town runs through the mangroves into the creek "every tidal cycle",[1] and a 2011 study found Tudor the most polluted of Mombasa's sewage-impacted creeks.[17] Any operation that holds water behind a barrage reduces the flushing that now dilutes that sewage. At Sihwa Lake in South Korea, water quality "drastically deteriorated" after a seawall closed the bay in 1994; the government later spent more than US$1.5 billion on sewage treatment, and the tidal plant built into the wall in 2011 improved circulation but not enough for the upper lake.[18] At La Rance, the barrage caused progressive silting and the loss of marine life during construction, though by 1976 the estuary was again "richly diversified".[6] The UK's Severn feasibility study predicted local extinctions of migratory fish and the loss of saltmarsh and mudflat.[19]

Mombasa has a local lesson. The 1929 Makupa Causeway blocked the free flow of water between Tudor and Port Reitz creeks, which maritime consultant Andrew Mwangura said had harmed marine life for years; the county reopened it with a bridge in 2022.[20] Fishermen at Shimanzi expected better catches once water flowed freely again.[21] A barrage would constrain the creek's other, seaward end.

Navigation

Dhows, fishing boats, tour boats and the English Point marina all use the creek mouth that the barrage would cross. The proposal would need a navigation lock or opening span; La Rance has had a lock since 1962.[6] No study of boat traffic through the Old Port has been found.

Cost and value

Tidal barrages are expensive for the power they produce. The UK government rejected the 320 MW Swansea Bay tidal lagoon in June 2018, with the Business Secretary saying it would supply about 0.15 per cent of the country's electricity and that offshore wind could provide the same power for about £400 million instead of £1.3 billion.[22] The Severn study concluded that other renewables and nuclear power generally offered better value.[19] Kenya's grid already draws about 83 per cent of its power from clean sources, mainly geothermal, hydro, wind and solar,[23] so a small, costly tidal plant would compete with cheaper clean options. The road tunnel, by contrast, answers a real traffic problem, and could be assessed on its own merits alongside the long-planned second Nyali bridge.[9]

Sources

References

  1. ↑ 1.0 1.1 1.2 1.3 Mangrove linkages to coral reef and seagrass ecosystem services in Mombasa and Takaungu, Kenya, J. O. Bosire, G. Okemwa and J. Ochiewo, Kenya Marine and Fisheries Research Institute, 2012, printed page 6.
  2. ↑ 2.0 2.1 Tide Tables and Port Information 2026, Kenya Ports Authority, December 2025, printed page 5.
  3. ↑ Nyali Bridge, Wikipedia, read 15 October 2026.
  4. ↑ 4.0 4.1 A Singapore icon turns 10!, PUB, Singapore's National Water Agency, 13 February 2018, pages 1, 7 and 8.
  5. ↑ Marina Barrage, Wikipedia, read 15 October 2026.
  6. ↑ 6.0 6.1 6.2 Annex IV metadata form: La Rance tidal barrage, OES-Environmental, hosted by Pacific Northwest National Laboratory, 27 June 2012, page 1.
  7. ↑ Rance Tidal Power Station, Wikipedia, read 15 October 2026.
  8. ↑ Nairobi, Mombasa and North Eastern major electricity consumers, Patrick Vidija, The Standard, 30 September 2026.
  9. ↑ 9.0 9.1 Plans for second Nyali bridge takes shape, Mohamed Ahmed, Business Daily, 3 October 2018.
  10. ↑ 10.0 10.1 Mombasa County Integrated Development Plan 2023-2027, County Government of Mombasa, 2023, printed page 84.
  11. ↑ A Review of Tidal Power Potential in Kenya, Aron Oronyi Ohuru, Multidisciplinary Journal of the Technical University of Mombasa, May 2021, page 2.
  12. ↑ Fort Jesus, Mombasa (Kenya), No 1295rev, ICOMOS evaluation, 2011, printed pages 17, 21 and 23.
  13. ↑ Fort Jesus nomination dossier, Government of Kenya and National Museums of Kenya, 2010, PDF pages 17 and 253.
  14. ↑ Dresden dropped from UN World Heritage List owing to new bridge, UN News, 25 June 2009.
  15. ↑ Decision 42 COM 7B.45, Lamu Old Town, UNESCO World Heritage Committee, 2018.
  16. ↑ Mangroves in peril: unprecedented degradation rates of peri-urban mangroves in Kenya, J. O. Bosire and others, Biogeosciences 11, 2623 to 2634, 16 May 2014.
  17. ↑ Sewage pollution in the coastal waters of Mombasa City, Kenya: a norm rather than an exception, E. O. Okuku and others, International Journal of Environmental Research 5(4), 2011, printed page 865.
  18. ↑ Environmental and ecological effects of Lake Shihwa reclamation project in South Korea: a review, Chang-Hee Lee and others, Ocean and Coastal Management, 2014, page 1.
  19. ↑ 19.0 19.1 Severn Tidal Power Feasibility Study: Conclusions and Summary Report, Department of Energy and Climate Change, October 2010, printed pages 4 and 5.
  20. ↑ Mombasa regains island status as bridge is ready, Patrick Beja, The Standard, 12 October 2022.
  21. ↑ Fishermen to benefit from Mombasa's restored island status, The Star, 10 October 2023.
  22. ↑ Proposed Swansea Bay tidal lagoon, Greg Clark, oral statement to Parliament, 25 June 2018.
  23. ↑ Kenya National Energy Compact 2025-2030 (draft), Ministry of Energy and Petroleum, July 2025, PDF page 7.
Retrieved from "https://wiki.pwani2050.jayshapiro.com/index.php?title=Tudor_Creek_Barrage&oldid=415"