Assessment and possible adaptation on urban heat Island, Case study: Rwanda

Abstract

Urban heat island take place when a town experiences temperatures much warmer than its peri urban regions or rural areas. The difference between developed areas and rural areas belongs on how the land surface areas for each environment absorb and keep the heat due to land modification caused by anthropogenic activities on natural ground soil. Natural plants undergo a process called transpiration whereby they get water from soil through their roots and store it into their stems and their leaves. Then, water is lost by small holes underside of the leaves. From there, water is converted into water vapor and lost into the atmosphere. This cycle repeats itself and is seen as natural air conditioner or cooling process of the land surface. Firstly, this research work assessed if there were climate changes caused by UHI in City of Kigali precisely in Gitega Sector (Urban) in comparison to City of Rwamagana (rural) in The Eastern Province of Rwanda during the last 36 years period. With the help of on-site data or meteorologic data from Rwanda Meteorological Agency, we calculated the average mean temperatures for the two locations namely Gitega Sector and City of Rwamagana. Expectedly, we found that Gitega had (28.3°/16.3°C) whereas Rwamagana had (27.7°/16.1°C) for 36 years’ period respectively. It was found the maximum temperature for Gitega sector was high of a half degree Celsius over Rwamagana area and on minimum temperature Gitega was still high of 0.2 degree Celsius than Rwamagana. Generally, the main feature characterizing UHI are the structures for example complex buildings, roads, bridges and other infrastructures because they absorb and reflect solar radiations more than natural spaces for instance forests and water courses. In metropolitan zones, these buildings tend to be compacted into a small area and green space is limited. Thus, creating UHI with high temperatures than its peri urban regions. In Rwanda, the urbanization rate has been increasing from 2011 to 2022, Urbanization rate refer to the share of total population living in an urban setting. It has increased from 16.94% to 17.57%. The urbanization often results in deforestation, habitat loss, and the extraction of fresh water from the environment which can destroy the biodiversity, alter species ranges and interaction