Land use change and classification in Chaohu Lake catchment from multi-temporal remotely sensed images

Abstract

Chaohu lake and its surrounding have received considerable attention in terms of water and sediment pollution investigations. In this study, the trend of changes in four key land uses in the catchment area was examined. Maximum Likelihood Supervised Classification (MLC) in ESRI© ArcGIS was applied to subsets of Landsat MSS, TM, ETM and OLI/TIRS images of 1979 to 2015. The results showed that the water bodies' position remained relatively stable, while the portions of land used for urban activities and agriculture consistently increased. The built-up areas increased from 3.5% in 1979 to 25.1% in 2015. Similarly, the agricultural land use increased from the area coverage of 29.8% in 1979 to 45.2% in 2015. Forested/vegetated land of the catchment substantially decreased during this period, from 59.8% in 1979 to 22.9% in 2015. Decades of improper land use activities and resource utilisation have led to ecological degradation of the basin which has manifested in serious eutrophication of the lake. The conflict between the economic development and the need to protect the ecosystem of Chaohu catchment has now become a management issue. Deliberate planning should be made to reduce the rate of conversion of the forested land area to agriculture and urban use.

Perubahan Tata Guna Lahan Sekitar Danau Galela

“…Seiring meningkatnya pertumbuhan penduduk, kegiatan pembangunan yang tidak berkelanjutan, urbanisasi yang tidak terencana, ekspansi pertanian yang agresif, perubahan iklim, dan perubahan terkait dalam penggunaan lahan dan tutupan lahan menyebabkan tekanan terhadap tata guna lahan berdampak pada penurunan keanekaragaman di sekitar danau Perubahan tata guna lahan mempengaruhi perubahan lingkungan global yang memiliki dampak terhadap kelangsungan hidup manusia (Lasanta et al, 2006;Bryan, 2013;Costanza et al, 2014). Meningkatnya pembukaan lahan untuk aktivitas pertanian, urbanisasi yang luas, deforestasi dan aktivitas sehari-hari umat manusia menghasilkan perubahan temporal dan spasial dalam penggunaan lahan yang akan mempengaruhi Danau Galela seperti regulasi hidrologi dan erosi tanah (Rawat & Kumar, 2015;Oyodetun, 2019). Pada skala lokal, perubahan penggunaan lahan mempengaruhi Daerah sekitar danau, sumber daya iklim mikro, tabel air tanah, proses degradasi lahan dan keanekaragaman hayati (Gong et al,2015).…”

Quantitative assessment of the drainage morphometric characteristics of Chaohu Lake Basin from SRTM DEM Data: a GIS-based approach

“…Landsat Satellite data: Multi-Spectral Scanner (MSS) and Operational Land Imager (OLI) -Thermal Infrared Sensor (TIRS) for the year 1979 and 2015 of spatial resolution f 79 m and 30 m, respectively, were sourced from the US Geological Survey (USGS) depository (https://earthexplorer.usgs.gov) and these were used for Land Use/Land Cover (LULC) classification. These imageries were registered in the same projection, the Universal Transverse Mercator (UTM) projection World Geodetic System (WGS) 1984 Zone 50 N and the Spectral Bands Green (0.5-0.6 µm), Red (0.6-0.7 µm), and Near Infrared (0.8-1.1 µm) as composite images were used for the classification (Oyedotun, 2019). Landsat images are known to be very vital in the classification of different landscape categories and components at a larger scale (Butt et al, 2015).…”

“…Image classification is the mostly-used conventional method in land-use change observation, especially for any Land Use/Land Cover (LULC) delineation activities because of its ability to create series of land cover maps (El Garouani et al, 2017). Here, the Maximum Likelihood Classification (MLC) supervised method in ArcGIS was applied to classify Landsat bands for 1979 and 2015 images, after they have been pre-processed, geo-referenced, mosaicking and sub-setting to the Area of Interest (AoI) (from Oyedotun, 2019). This classification method (MLC) is based on the likelihood of a pixel (Picture element) that belong to a class is assumed (in theory) to be the representative of the classes that are evenly and equally distributed with the certainty of maximum likelihood of the distribution (El Garouani et al, 2017).…”

“…Lake Chaohu, the fifth largest freshwater lake in China, is a shallow eutrophic lake with catchment areas of 13,350 km 2 and it major inflowing rivers in the basin accounting for over 80% total runoff that feeds the lake with only one outlet (Jiang et al, 2014;Oyedotun, 2019;Xue et al, 2017). The importance of the Lake and its basin area to the ancient and recent civilizations have made it to be the subject of diverse academic studies and investigations.…”

“…The focus of these studies varied but most are on the impact of land-use activities, especially agricultural activities, on the pollution of sediments and Rivers of the basin (e.g., Jiang et al, 2014;Kong et al, 2013;Shau et al, 2016;Wen et al, 2012;Zan et al, 2011). Other studies examined the outbreak of cyanobacteria bloom (Shang & Shang, 2005); Spatio-temporal variations of the bacterioplankton community composition of the lake (Wei et al, 2008); and the implication/benefits of land-use changes and human activities on the Lake Chaohu and its environment (e.g., Chen et al, 2013;Huang et al, 2013;J-H. Wang et al, 2012;Kang et al, 2016;Li et al, 2009;Liu et al, 2012;Oyedotun, 2019;J. Tang et al, 2015;Wu et al, 2010;Xue et al, 2017;Yang et al, 2011;Yu et al, 2011;W.…”