Effects of Urban Land Use/Cover Dynamics on Peri-urban Natural Environmentin Nekemte City, Oromia, Ethiopia
Tolera Megersa,
Taffa Tulu,
Mekuria Argaw
Issue:
Volume 3, Issue 3, May 2018
Pages:
51-60
Received:
12 April 2018
Accepted:
14 May 2018
Published:
4 June 2018
Abstract: The urbanization process has led to the steady growth of cityat the expense of peri-urban natural environment. This study was conducted in the Nekemte city, Oromia Region at Western part of Ethiopia. The research was aimed to assess the effects of urban land use/ cover dynamics on natural environment through the interpretation of three years’ time series images and psycho-chemical analysis of surface water quality of the study site. Land use classification maps were developed by using geos patial methods, remote sensing and Geographic Information System (GIS). Study area land use/ cover mapping and change detection analysis was conducted by Arc-GIS software. Urban land use and cover dynamic analysis revealed that built-up areas have been increased during 1996 to 2016 resulting in substantial reduction of forest area, cultivated land, grazing land, wetland and riparian forest. Forest and wetland, which are the focuses of this research, have been continuously decreased from 17%, and 14% in 1996 to 5.1% and 2.7% in 2016, respectively, with an average annual urban growth rate of 3.65% within 20 years, resulted in an increased mean annual local temperature, variability of rainfall and relative humidity and surface water quality reduction. Projected values indicated that built up areas will be increased continuously for the coming 10 years. Continuous conversion of forest, wetl and land and other land cover type to urban land had resulted into varied and extensive natural ecosystem disturbances; local climate change biodiversity loss and surface water quality reduction. Population growth, migration and economic development are the main identified factors contributing for urban land expansion. Impacts of urban expansion on peri-urban environment can be reduced through controlling population growth and incorporating environmental issues in any urban and economic development program.
Abstract: The urbanization process has led to the steady growth of cityat the expense of peri-urban natural environment. This study was conducted in the Nekemte city, Oromia Region at Western part of Ethiopia. The research was aimed to assess the effects of urban land use/ cover dynamics on natural environment through the interpretation of three years’ time ...
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Network Temperatures and Flow Rate: Case Study of District Heating in Canberra, Australia
Stanislav Viktorovich Chicherin
Issue:
Volume 3, Issue 3, May 2018
Pages:
61-68
Received:
6 July 2018
Accepted:
16 July 2018
Published:
9 August 2018
Abstract: The purpose of this paper is to highlight the relevance of district heating (DH) in the country where, in general, there is no such system and, specifically, to develop and implement a helpful approach for designing a DH network combining thermal and hydraulic considerations to simulate the energy behaviour of such network. The nonlinear model of the supply and return temperatures describes the dynamics of a DH system with an appropriate accuracy. The results of the generated scenarios are partial load values obtained for each category. The data on the daily heating power demand was transformed into an outdoor temperature dependence curve used to compute the flow rate for each of the scenario. Under the designed condition, the flow is determined and regulation approaches are elaborated. The resulting flow is quite stable. Taking into account the deficiencies of conventional evaluation for DH networks, this study excludes the hypothesis of constant outdoor temperature, and analyzes the influence of outside temperature on the heat losses and electricity consumption for DH networks based upon the state-space method. The obtained results are achieved without significant investments into a DH system just by adjusting and controlling temperatures and flow rates of a heat radiator circulating in the network.
Abstract: The purpose of this paper is to highlight the relevance of district heating (DH) in the country where, in general, there is no such system and, specifically, to develop and implement a helpful approach for designing a DH network combining thermal and hydraulic considerations to simulate the energy behaviour of such network. The nonlinear model of t...
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