THE BAR BEACH SHORELINE OF LAGOS AND COASTAL FLOODING

agos is a metropolitan area (6°27′11″N 3°23′45″E) which originated on islands separated by creeks, such as Lagos Island and Victoria Island fringing the southwest mouth of Lagos Lagoon while protected from the Atlantic Ocean by long sand spits such as Bar Beach, which stretch up to 100 km east and west of the mouth. This is the main beach on Victoria Island, alongside Ahmadu Bello Way and one of the more popular beaches in Lagos State. Bar Beach is the main (inner city) beach and runs from the Institute of Oceanography in the west to the Eko Hotel in the east.
Bar Beach is named after the sand spits/bars (moles) that characterized the coastline of Lagos, not because of the myriad of bars that run along the beach itself.
Lagos has a shoreline of about 181.71 km, which stretch from the water front of Kweme in Badagry LCDA to Ode Omi in Ibeju LCDA. By nature/location it is a coastal state bordered by the Atlantic Ocean on the south, Ogun State on the north and east, and Benin Republic on the west.
The Atlantic Ocean which borders the state on the south is driven by Long Shore Currents that constantly depletes the sediments and resources of the beaches. The Lagos shore line is populated predominantly by sands, wetlands and bits of vegetation.
Longshore drift consists of the transportation of sediments (clay, silt and sand) along a coast at an angle to the shoreline, which is dependent on prevailing wind direction, swash and backwash. This process occurs in the littoral zone, and in or within close proximity to the surf zone. The process is also known as longshore transport or littoral drift.
Longshore drift is influenced by numerous aspects of the coastal system, with processes that occur within the surf zone largely influencing the deposition and erosion of sediments. Longshore currents can generate oblique breaking waves which result in longshore transport.
Over the years Lagos has experienced a loss in its beaches and shore lines as a result of factors which could be attributed to climate change and abandoned vessels along the coastline.
Within the Lagos metropolitan area are four lagoons (Lagos, Lekki, Ologe & Magbon). The Lagos lagoon is more than 50 km long and 3 to 13 km wide, separated from the Atlantic Ocean by long sand spit 2 to 5 km wide, which has swampy margins on the lagoon side. Its surface area is approximately 6,354.7 km² (Obafemi, 2008). Lagos Lagoon empties into the Atlantic via Lagos Harbour, a main channel through the heart of the city, 0.5 km to 1 km wide and 10 km long also known as Commodore Channel. While Lekki Lagoon sometimes spelled Leeki, is a lagoon located in Lagos and Ogun states in Nigeria. The lagoon lies directly to the east of Lagos Lagoon and is connected to it by a channel. It is surrounded by many beaches.
SHORELINE PROTECTION MEASURES
As of May 2009 the project was still in its dredging phase. The power and potential violence of the Atlantic Ocean is expected to be tamed by a new offshore sea wall. A century of accelerating land loss that once threatened Lagos is expected to be reversed. Ships are taking sand from outside the reclamation area and repositioning it to recover the natural coastline. A new sea wall would safely deflect the threat of flooding from an unpredictable ocean. It would protect Lagos and the new city of Eko Atlantic. In certain parts of Bar Beach the land being reclaimed can already be seen.

A seawall is a form of coastal defense constructed where the sea, and associated coastal processes, impact directly upon the landforms of the coast. The purpose of a seawall is to protect areas of human habitation, conservation and leisure activities from the action of tides and waves (Kampuis, 2010).  As a seawall is a static feature it will conflict with the dynamic nature of the coast and impede the exchange of sediment between land and sea (Shipman et al, 2007).
The coast is generally a high-energy, dynamic environment with spatial variations occurring over a wide range of temporal scales (Allan et al, 1997).The shoreline is part of the coastal interface which is exposed to a wide range of erosional processes arising from fluvial, aeolian and terrestrial sources, meaning that a combination of denudational processes will work against a seawall (Fletcher et al, 1997).

A seawall works by reflecting incident wave energy back into the sea, thereby reducing the energy and erosion which the coastline would otherwise be subjected to (Kajenra, 2011). In addition to their unsightly visual appearance, two specific weaknesses of seawalls exist. Firstly, wave reflection induced by the wall may result in scour and subsequent lowering of the sand level of the fronting beach (Massenlink et al, 2003). Secondly, seawalls may accelerate erosion of adjacent, unprotected coastal areas because they affect the littoral drift process (NOAA, 2007). This point is true as evidence shows the Kuramo beach has been destroyed by the waves of the Atlantic Ocean reflected by the sea wall.
CONSEQUENCES OF SEAWALL ON SHORELINE
Last year we witnessed an Ocean surge that claimed many lives at the Kuramo beach. Just in January, 2013 from satellite pictures seen above the Atlantic Ocean has broken through the beach into the Kuramo Waters. These are facts and not fiction I believe it is very likely the seawall has been compromised. That is, the strength of the wall is in question. Its power of erosion would increase along the Lagos shoreline and would affect states like Ondo, Delta and Bayelsa as time goes on. Last year we warned at a forum organized by Heinrich boll foundation in Lagos that the Kuramo and its environs would be affected but, the contractors handling the project rejected our suspicion. The rate at which the coastline is being lost is alarming. From
research findings, if nothing concrete is done we may have the Atlantic Ocean break into the Lagos Lagoon and that may be the end for the State.
The rate at which the coastline is being lost is alarming. From research findings if nothing concrete is done we may have the Atlantic Ocean break into the Lagos Lagoon and that may be the end for the State.
Sea level rise creates an issue for seawalls worldwide as it raises both the mean normal water level and the height of waves during extreme weather events, which the current seawall heights may be unable to cope with (Allan et al. 1999). The International Panel on Climate Change (IPCC) (1997) suggested that sea level rise over the next 50 – 100 years will accelerate with a projected increase in global mean sea level of +18 cm by 2050 AD. This data is reinforced by Hannah (1990) who calculated similar statistics including a rise of between +16-19.3 cm throughout 1900–1988.
It is advisable that the project be halted pending when unbiased assessors from international agencies assisted by local experts in Oceanography and geomorphology would be able to suggest a way around this disaster that has already claimed many lives.