Wa Municipality lays in the Savannah high plains, which generally, is gently undulating with an average height between 160 m and 300m above sea level. Low lying areas are found in the following localities; Charia, Zingu, Kperisi to the north and Piisi, Dapouha, Boli, Sing, Biihe and Busa to the south. Valleys in the low lying areas collect and retain water over long period during the rainy season.
They also constitute the two main drainage systems in the capital. These are the Sing-Bakpong and its tributaries to the south and Billi and its tributaries to the north. The streams are seasonal and thus dry up during the long dry season thereby reducing available water for agriculture and other uses such as domestic, industrial and construction (Wa Municipal, 2012).
Geology and soils
Underlying the Municipality are predominantly Pre-Cambrian, granite and metamorphic rocks that have seen lesser weathering than similar rock types elsewhere in the country due to low rainfall, high evapo-transpiration and less vegetation. Nevertheless, sourcing water from boreholes has been successful because the rocks have well-developed fracture systems.
This situation has created the opportunity for the development of a quarry on the Wa Busa road.
There are two main types of soil, the laterite and the savannah ochrosols. The others are clay found in the Charia community which is famous for pottery and sand found in Nakore.
The laterite soil occurs abundantly all over the Municipality and is excavated for roads and housing construction. The savannah ochrosols on the other hand are shallow but support the growth of a variety of crops including millet, sorghum, soya beans, groundnuts, rice and yams.
The vegetation is one of the guinea savannah grassland type, made up of short trees with little or no canopy and shrubs of varying heights and luxuriance, with grass ground cover in the wet season. Commonly occurring trees are shea, dawadawa, kapok and baobab. Cashew and mango are exotic species that grow well in the area.
Wa Municipality has two marked seasons, namely, the wet and dry seasons. The South-Western Monsoon winds from the Atlantic Ocean bring rains between April and October, while the North-Eastern Trade winds from the Sahara Desert bring the long dry season between November and March. The mean annual rainfall varies between 840mm and 1400mm.
Most of the rainfall occurs between June and September and it is not unusual to have very high rainfall figures concentrated in a few rainy days. One feature of the rainfall pattern is that it tends to occur in heavy downpours thus, that encourages run-off rather than soil moisture retention.
Erratic rainfall regime is clearly shown in the water balance, which is a reflection of the poor soil moisture condition in the area. It has been calculated that there are four humid months, in terms of soil moisture conditions and the period is only adequate for the cultivation of crops such as millet, guinea corn, yam, groundnuts and beans. The rainfall pattern is irregular and unreliable. Sometimes, it results as long period of no rain during the farming season which affects harvest.
Date Created : 11/17/2017 6:03:06 AM