Physical Characteristics

Physical Characteristics a) Geology The geology of the LEKMA is broadly made up of Precambrian Dahomeyan Schists, Granodiorites, Granites Gneiss and Amphibolites to late Precambrian Togo Series comprising mainly Quartzite, Phillites, Phylitones and Quartz Breccias.

Apart from these formations Palaeozoic Accraian Sediments – Sandstone, Shales and Interbedded Sandstone-Shale with Gypsum Lenses are also found in the area. Soils found in the area are categorised into four main groups namely: drift materials resulting from deposits by wind blown erosion; alluvial and marine motted clays of comparatively recent origin derived from underlying shales; residual clays and gravels derived from weathered quartzites, gneiss and schist rocks, and lateritic sandy clay soils derived from weathered Accraian sandstone bedrock formations.

The coastline is characterised at certain portions by a series of resistant rock outcrops and platforms. There are however sandy beaches near the mouth of the lagoons. There is also severe coastal erosion because strong coastal and wind action brought about by the exposed coastline and close proximity of the continental shelf. Apart from the issue of coastal erosion, it is also observed that the lagoon systems are relatively narrow and flushing has been impeded by siltation or the construction of embankments, which have restricted tidal flow. b) Climate LEKMA lies in the Savannah zone which experiences a double maxima rainy season pattern.

The average annual rainfall is about 730mm, which falls primarily during the two rainy seasons. The first season begins in May and ends in mid-July while the second season begins in mid-August and ends in October. Rainfall is usually characterised by quick and short intensive storms and causes flooding in areas of poor drainage. The predominant wind direction in the LEKMA area is from the WSW to NNE sectors with speeds normally ranging between 8 to 16 km/hr. High wind gusts are characterised by thunderstorm activity, which pass in squall along the coastal portions. The maximum wind speed record in the district is 107.4 km/hr (58 knots) and such winds associated with thunderstorm activity often cause damage to property by removing roofing material.

The annual temperature figures are also relatively stable with very little variation in annual temperature figures. August, the coolest month, usually comes with a mean temperature of 24.7°c while the hottest period is found in March with a mean of 28°c. With an annual average of 26.8°c in temperature and the proximity of the area to the equator, the daylight hours are practically uniform during the year. Relative humidity in the area is also generally high varying from 65% in the mid-afternoon to 95% at night. c) Vegetation i. Terrestrial Vegetation The vegetation of the municipality was believed to have been covered by dense forest but currently only a few remnant trees have survived due to a multiplicity of factors relating to rapid urbanisation and limited enforcement of laws protecting the terrestrial vegetation. The three key vegetation zones are made up of shrub lands, grassland and coastal lands.

The grasses comprise a combination of species found in the undergrowth of forests which are usually short, and rarely grow beyond one metre. There is however a small green belt near the Teshie Coastal area which is seriously under threat of encroachment. Part of Green Belt Encroachment on Green Belt The coastal zone is also under two broad classification namely, wetland and dunes. The coastal wetland zone is very productive and provides an essential ecosystem for marine and terrestrial life-mainly bird life which have an important primary production role in providing nutrients for prawns and juvenile fish in the lagoon systems. In recent times, wetlands are however being encroached upon. Protection of the coastal wetland zone is very important to the long-term sustainability of the fishing industry which is common among the indigenes. Mangrove Swamps along the coastal zone The dune lands which are formed through a combination of wave and windaction are very unstable and extend several hundred metres in certain portions of the coastline. Coconuts and palms are examples of species that grow well in the area and provide protection of the coast as well as an economic crop.

The coconuts were planted in the 1920s but it is estimated that over 80% of those plantations have disappeared as a result of felling, disease and coastal erosion. The loss of these trees is one of the principal reasons for the severity of erosion in some areas. It is also worth mentioning that apart from the above natural vegetation, a number of introduced trees and shrubs also thrive in the area such as neem trees, mangoes, cassias, avocados, palms and bouganvilia. ii. Terrestrial Fauna Due to urbanisation of the landscape of the municipality, different categories of animals have been pushed further inland or northwards. There are however many species of snakes (some venomous) and lizards found throughout the area and large numbers of domestic animals such as donkeys, sheep, goat, chicken etc.

A wide range of indigenous, migratory and exotic bird species are also found in the lagoon regions but the dangers posed by pollution threatens the sustainability of such species. However bird life is generally diverse in the area and in spacious residential areas it is found to be prolific. iii Aquatic Vegetation Apart from mangroves and salt marsh grasses, which are found in the intertidal zone, sea grasses or attached algae are also very common in rocky areas and wave cut platforms which facilitate the sustainability of the coastal ecosystem for the survival of shrimps, prawns and many species of fin fishes.

The ocean floor regime is however too unstable to support large areas of sea grass. iv Aquatic Fauna The open lagoon systems is home to a wide range of crustacean, mollusks, gastropods, predatory and bottom feeding fish. These areas are important breeding grounds due to adequate protection against large predator species and a continual supply of nutrients and organisms for food. Such areas have however been modified by development and increasing levels of pollution. In this regard, some species in the lagoons are no longer suitable for human consumption. Protection of the water quality and vegetation in the lagoons is therefore important for the long-term sustainability of aquatic fauna along the coastline.

The common species of fish that dominate the local fishing industry are grouper, mackerel, cassava fish, African lookdown, sole shark and tiger fish. Stocks of off shore species have not been depleted mainly because fishing techniques result in a significant loss of smaller fish from nets. Evidence suggests that on-shore species are nearing exhaustion caused by excessive catches of juvenile and small fish. The loss of this resource will have a substantial impact on the indigenous population of the area whose livelihood is dependent on fishing. Apart from harbouring a variety of important commercial fish species like tilapia and catfish, the lagoons also provide very breeding grounds for animals, which are adapted to the characteristic coastal Savannah vegetation. v. Drainage

The drainage catchment area of the municipality is found within the Songo-Mokwe area which covers about 50km2, draining the area of Teshie to the ridgeline with the Sakumo II catchment. Two main streams drain the area flowing into the Mokwe and Songo Lagoons. Much of this catchment is undergoing illegal residential development leading to extensive flooding during the rainy season. General factors leading to flooding in the LEKMA Area. • Natural Features Natural features such as the underlying geology, soil conditions and localised topographic features create some drainage problems. The majority of the problems are created by the growing urbanisation of the area and the impact that this has on increase surface water runoff and flooding in low lying areas. As the municipality expands and surface water runoff increases there will be a corresponding increase in siltation and more severe floods downstream, especially in areas surrounding the lagoons.

If this situation is to be avoided engineering and conservation measures will need to be applied to reduce the rate of runoff. There is also the need to introduce measures to protect the upper catchment areas and streams where development may take place. • Physical Development within water ways. In recent time there has been unauthorised development along water ways due to ineffective development control mechanisms thereby causing severe floods in such areas. This calls for proactive measures at enforcement to ensure sanity in the system. • Siltation of drains Most channels are also heavily silted and choked with refuse thereby hampering the smooth flow of storm water. A well-organised public health and environmental enhancement programme for seasonally clearing drains is required to ensure they remain free flowing to help address the problems of flooding.