Assessing the impact of Dhanmondi lake on it s surrounding environment in terms of relative humidity and temperature

Abstract

Dhaka is a city which was known by its canals and lakes, which were connected to the three main rivers that encircled it. In the frenzy of urbanization, Dhaka has seen a drastic reduction of its lakes and canals as well as wetlands resulting in the brutal transformation of urban tissue. Dwindling water bodies has an adverse impact on the urban environment of Dhaka which needs to be assessed. Systematic study on the micro climatic and ecological impact of the urban water bodies is rather scant. It is understood that water bodies have a therapeutic as well as ecological value and helps in regulating environmental balance. Water bodies also play the role of climate modifier by regulating the temperature, relative humidity and breeze. Dhaka's water bodies are still an integral part of the urban eco-system. They act as water retention basins during the Monsoon; and besides being the sources of biodiversity of the area, they are an important part of the scenic beauty and open space. The study is an attempt to assess the impact of Dhanmondi Lake on its surrounding environment in terms of Temperature and Relative Humidity. This paper describes a climatic analysis of efficiency and impact of water bodies for changing micro climatic behavior of an urban area adjacent to lake during the warm humid season in Dhanmondi, Dhaka. In this study, the Temperature and humidity regimes were observed at seven different tissues of Dhanmondi Lake. The observation procedure is then presented, followed by a comparison of the data obtained from seven different situations. The effects attributed to the water body are then analyzed and finally the significance of the findings is discussed and their implications summarized. The findings indicate that inclusion of water bodies in urban areas would reduce the air temperature and also can increase relative humidity under warm humid weather conditions. Temperature varied up to 6.74 ⁰c from the daily maximum temperature of Dhaka of that specific day from the average reading of a tissue. Variation in relative humidity is maximum 4.0% in the morning average and 5.3% in the evening average between the daily weather data of Dhaka and average relative humidity of a tissue on a specific day respectively. The study ended up with some specific recommendations like creating wind channels, variations in heights and maximum ground coverage in the master planning of an urban area, using heat proofing measures and green roofs as building design considerations thereby to create better living environment in the residential areas near lake by extending its climatic effect.