An alternative method for long-term land cover change detection: a case study of Hasanlar Dam

Abstract

Dams which needed to drinking and irrigation water supply, flood control etc. at first have undertaken an another task with hydroelectric power which emerged from the increasing energy demand due to population growth, technological developments and changes in consumption habits in recent years. This process has accelerated from the 1980s which was the beginning of the increasing trends in renewable energy sources due to the environmental impacts of fossil fuels. However, even though dam type hydroelectric power plant project is a renewable energy, it has some adverse effects on ecosystems. The changing flow regime with the intervention to the river generally results in destruction and fragmentation in the riparian ecosystem. This change in the land cover can lead to modification on the microclimate, thus it can change the hydrological cycle of the basin. For this reason, the monitoring of the change in the land cover at the dam and its surroundings is important for revealing the effects of the project. In this context the Hasanlar Dam in Düzce province was examined in the scope of this study. The land cover change has been determined in two temporal periods through 1:25000 scale topographic maps date on 1960, 1982 and 2013. The land cover which is consist of 4 classes was obtained by visual classification method. The amount of change was determined as the unit by grid method. It was observed that forest areas showed a decreasing tendency after the dam construction during the first temporal period but an increase was shown later. On the other hand it has been determined that non-vegetated areas are transformed into orchard predominantly. As a result, it has been seen that the proposed method can provide an effective analysis for the land cover change detection when old dated aerial photos or satellite images can not be reached.