IMPLICATIONS OF URBAN CANYON IN ACHARA LAYOUT OF ENUGU URBAN. SOUTH EAST NIGERIA

Abstract Urban climate is vital aspect in urban design that is influenced by density, human settlement and the physical properties of urban surfaces. An urban canyon is a basic urban surface unit that can be seen repeatedly throughout urban areas. It consists of the geometric combination of horizontal and vertical surfaces where the building arrangement acts as the walls and the streets is the ground. This paper discusses the theory and the implications of urban canyon in modern buildings highlighting the impacts of street geometry and wind flow, using Achara layout as a case study. The primary data is Achara Layout in Enugu, capital of Enugu State, Nigeria. Empirical research method was applied and climatic factors such as wind speed, air temperature, relative humidity, etc were measured for a period of 5 days between March and April, 2010 at different locations within Achara layout to determine the thermal comfort and microclimate situation of the study region. The results show that higher air temperatures existed for longer hours in point 16 compared to those in point 2 and this reflects the fact that a more open and exposed urban canyon will result in longer hours of high daytime air temperature within it. This study confirms that the best orientation for urban street canyons is N/S and that diagonal orientation (NW/SE or NE/SW) are a good compromise