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Suspended sediment fluxes in an Indonesian river draining a rainforested basin subject to land cover change
F. A. Buschman,A. J. F. Hoitink,S. M. de Jong,P. Hoekstra
Hydrology and Earth System Sciences Discussions , 2011, DOI: 10.5194/hessd-8-7137-2011
Abstract: Forest clearing for reasons of timber production, open pit mining and the establishment of oil palm plantations generally results in excessively high sediment loads in the tropics. The increasing sediment fluxes pose a threat to coastal marine ecosystems such as coral reefs. This study presents observations of suspended sediment fluxes in the Berau river (Indonesia), which debouches into a coastal ocean that can be considered the preeminent center of coral diversity. The Berau is an example of a small river draining a mountainous, relatively pristine basin that receives abundant rainfall. Flow velocity was measured over a large part of the river width at a station under the influence of tides, using a Horizontal Acoustic Doppler Current Profiler (HADCP). Surrogate measurements of suspended sediment concentration were taken with an Optical Backscatter Sensor (OBS). Tidally averaged suspended sediment concentration increases with river discharge, implying that the tidally averaged suspended sediment flux increases non-linearly with river discharge. Averaged over the 6.5 weeks observations covered by the benchmark survey, the tidally averaged suspended sediment flux was estimated at 2 Mt y 1. Considering the wet conditions during the observation period, this figure may be considered as an upper limit of the yearly averaged flux. This flux is significantly smaller than what could have been expected from the characteristics of the catchment. The consequences of ongoing clearing of rainforest were explored using a plot scale erosion model. When rainforest, which still covered 50–60 % of the basin in 2007, is converted to production land, soil loss is expected to increase with a factor between 10 and 100. If this soil loss is transported seaward as suspended sediment, the increase in suspended sediment flux in the Berau river would impose a severe sediment stress on the global hotspot of coral reef diversity. The impact of land cover changes will largely depend on the degree in which the Berau estuary acts as a sediment trap.
Assessment of Climate Trends and Land Cover/Use Dynamics within the Somone River Basin, Senegal  [PDF]
Ndeye Yacine Barry, Vieux Boukhaly Traore, Mamadou Lamine Ndiaye, Osemwegie Isimemen, Hauhouot Celestin, Bienvenu Sambou
American Journal of Climate Change (AJCC) , 2017, DOI: 10.4236/ajcc.2017.63026
Abstract: This study was undertaken mainly to 1) investigate temporal trends in annual rainfall and temperature; 2) identify discontinuities in the time series; and 3) assess the Land Use/Land Cover Change (LULC) in the Somone coastal lagoon, within the river basin. The study examined temporal trends in rainfall (1931-2016) and temperature (1961-2016) datasets of Somone river basin, and breaks in time series using Mann-Kendall non-parametric test and other suitable statistical tools. Temporal evolution in LULC was assessed for the years 1954, 1978, 2003 and 2016. Analysis indicates a significant decreasing trend in precipitation over the basin. These trends are much more pronounced for minimum and average rainfall than for maximum and annual amplitudes. Contrary to precipitation, surface air temperature shows a significant increasing trend for its minimum and averages, and a decreasing trend for its maximum and amplitudes. A significant break in precipitation was observed in 1958, while surface air temperature presents much longer breaks within the years 1975 and 1977, and 1991 and 1993. A more direct implication of climate change on LULC patterns is increased in unproductive salt pans (Sabkhas). Increase in Sabkhas gave rise to conversion of forest lands to agricultural lands of local farmers in search for fertile soils to cater for the food needs of a growing population. Otherwise, the development of the settlements, favored by the tourism activity and agriculture crisis, is another cause of croplands decreasing. The findings of the present research clearly indicate that the impacts of climate change are exacerbated by rapid urbanization in the basin.
Characterization of land cover types in Xilin River Basin using multi-temporal Landsat images

CHEN Siqing,LIU Jiyuan,ZHUANG Dafang,XIAO Xiangming,

地理学报 , 2003,
Abstract: This study conducted computer-aided image analysis of land use and land cover in Xilin River Basin, Inner Mongolia, using 4 sets of Landsat TM/ETM+ images acquired on July 31, 1987, August 11, 1991, September 27, 1997 and May 23, 2000, respectively. Primarily, 17 sub-class land cover types were recognized, including nine grassland types at community level: F. sibiricum steppe, S. baicalensis steppe, A. chinensis + forbs steppe, A. chinensis + bunchgrass steppe, A. chinensis + Ar. frigida steppe, S. grandis + A. chinensis steppe, S. grandis + bunchgrass steppe, S. krylavii steppe, Ar. frigida steppe and eight non-grassland types: active cropland, harvested cropland, urban area, wetland, desertified land, saline and alkaline land, cloud, water body + cloud shadow. To eliminate the classification error existing among different sub-types of the same gross type, the 17 sub-class land cover types were grouped into five gross types: meadow grassland, temperate grassland, desert grassland, cropland and non-grassland. The overall classification accuracy of the five land cover types was 81.0% for 1987, 81.7% for 1991, 80.1% for 1997 and 78.2% for 2000.
Mapping the Spatial Distributions of Water Quality and Their Interpolation with Land Use/Land Cover Using GIS and Remote Sensing in Noyyal River Basin, Tamil Nadu, India  [PDF]
Geetha Selvarani Arumaikkani, Sivakumar Chelliah, Maheswaran Gopalan
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.58017
Abstract: Noyyal River is historically, ecologically and culturally significant river in Kongu region of western Tamilnadu. More than 100 villages are situated along the banks of the Noyyal River and it’s the was the best site of inhabitation on both the sides of the river up to 3 km from the river before the emergence of the issue of industrial pollution. But now river Noyyal was highly polluted by domestic and industrial growth by discharging of both domestic and industrial are discharged without any treatment. So methodology was proposed to identify the suitable zone for groundwater quality by using land use/land cover data along with groundwater quality in analytic hierarchy process. Suitability of groundwater for drinking was identified in the study area by collecting 63 samples in both postmonsoon and premonsoon as per Indian standards. To evaluate the land use pattern of the study area, land use/land cover map was prepared from satellite images of LISS III by using supervised classification according to National Remote Sensing Agency (NRSA) using Erdas imagine 8.4 software. Using ArcGIS software, weighted overlay analyses were carried out to identify the suitable zones for groundwater quality in postmonsoon and premonsoon and finally these two thematic maps were integrated with land use/land cover map to identify the suitable zone for quality of water. The interpretation shows that groundwater in most of the locations were unsuitable for drinking purposes.
Land cover and conservation state of a region in the Southern limit of the Atlantic Forest (river Maquiné basin, Rio Grande do Sul, Brazil)
Becker, F. G.;Irgang, G. V.;Hasenack, H.;Vilella, F. S.;Verani, N. F.;
Brazilian Journal of Biology , 2004, DOI: 10.1590/S1519-69842004000400004
Abstract: the state of conservation of atlantic forest in the maquiné river basin was assessed using land cover data obtained from landsat tm 5 satellite imagery (october 1995). the initial analysis examined the distribution of the relative areas of each land-cover type according to landscape slope classes, potential vegetation zones, and a 90 m riparian buffer. land-cover classes were then regrouped into categories representing "low", "intermediate", and "high" degree of anthropogenic alteration. results indicate that about 70% of the land cover of the maquiné river basin has been highly altered as a consequence of replacement of natural forests by agriculture. presently, a recovery process seems to be underway, contrasting with the historical trend towards deforestation. there are large areas of secondary vegetation in intermediate (34.8%) and advanced successional stages (20.2%), particularly across the range of the montane forest and of forest formations that occur at elevations higher than 800 m (high-montane dense ombrophilous forest and mixed ombrophilous forest). the geographical location at the southern limit of the atlantic forest stricto sensu and comparison of the results with data on the state of conservation of the atlantic forest in rio grande do sul indicate that the maquiné river basin is an important area for conservation. some points regarding future research and conservation management are also discussed.
Study on hydrological response to land use and land cover change in Dali River Basin, Shaanxi Province

LI Li-juan,JIANG De-juan,YANG Jun-wei,LI Jiu-yi,

地理研究 , 2010,
Abstract: In recent years, the research on the hydrological response to Land Use/Land Cover Change (LUCC) has been an international frontier and a key problem. In Dali River Basin, LUCC, including soil and water conservation, have strong impacts on water cycle and water balance. Therefore, it is essential to study hydrological response to LUCC in this river basin. First, based on the land use data in 1990, 1995 and 2000, the spatial and temporal characteristics of LUCC were analyzed. And then, using the Time Series Analysis Method of characteristic parameters and the rainfall-runoff model, hydrological response to LUCC in Dali River Basin were studied. The results showed that farmland and grassland were the primary land use types in Dali River Basin. For recent 10 years, the area of farmland and grassland decreased and the area of forest and constructed land increased gradually. The mean annual and monthly runoff showed a distinct decreasing trend. LUCC and soil and water conservation distinctly decreased the mean annual runoff and the runoff during flood season, and increased the runoff during non-flood season. Furthermore, compared with precipitation variation, human activities were dominant factors for these hydrological responses, and for this reason, the decreased runoff reached 2616.6×104 m3 during 1990-2000, which accounted for 62.19% of the total amount of the decreased runoff.
Morphometric Analysis of a Tropical Medium River System: A Case from Bharathapuzha River Southern India  [PDF]
P. P. Nikhil Raj, P. A. Azeez
Open Journal of Modern Hydrology (OJMH) , 2012, DOI: 10.4236/ojmh.2012.24011
Abstract: Baseline morphometric information at a sub basin level is essential to develop appropriate strategy for sustainable, socially acceptable, ecologically benign and economically viable development of a river basin. The present study was carried out in one of the less studied Bharathapuzha river basin (BRB), the second longest river in the state of Kerala, India. The annual discharge of the river is 3.94 km3. Nevertheless the basin, which receives about 1828 mm of annual rainfall, in recent years has been facing dearth of water. We used GIS and RS tools to study the morphometric characteristics of the basin. The seventh order main river is formed by several lower order streams forming a dentritic flow pattern. Basin geology, slope and rainfall pattern in the basin determine the morphometric characteristics of the basin. The linear aspects of the basin including stream length ratio and bifurcation ratio indicate the role of relief in the basin while the areal ratios indicate the elongate nature of the basin.
Study on Land Use/Cover Change in Upper Reach of Yangtze River Basin Based on the DEM Data

LIU Ruimin,YANG Zhifeng,SHEN Zhenyao,DING Xiaowen,WU Xing,LIU Fang,
,杨志峰,沈珍瑶,丁晓雯,伍 星,刘 芳

地理科学进展 , 2006,
Abstract: Today, more and more research has focused on the issues of Global Environmental Change(GEC) and sustainable development(SD), and the study of land use/ cover change is a hot subject and front issue among all the researches. The serious eco-environment problems have been an obstacle to the economic and social development in upper reach of Yangtze River Basin, and the natural degradation also restricts the sustainable development for upper reach and all regions of Yangtze River Basin. Based on the DEM data, this paper analyzed the relationship of land use with elevation, slope and aspect in 2000. It is discovered in the result that the types of land use in upper reach of Yangtze River Basin in 2000 changed with different grade of elevation, slope and aspect. It is also indicated that these topographical factors have important influence on land use in upper reach of Yangtze River Basin. In order to protect the e-co-environment and to promote the sustainable development in the upper reach and all regions of Yangtze River Basin, land use management should be enhanced based on the local condition. And further research should be developed to optimize land use and improve land cover with the influenced factors such as elevation, slope and aspect.
Assessing the Impacts of Land Use and Land Cover Changes on Hydrology of the Mbarali River Sub-Catchment. The Case of Upper Great Ruaha Sub-Basin, Tanzania  [PDF]
Edmund Mutayoba, Japhet J. Kashaigili, Frederick C. Kahimba, Winfred Mbungu, Nyemo A. Chilagane
Engineering (ENG) , 2018, DOI: 10.4236/eng.2018.109045
Abstract: Intensification of agricultural land use and population growth from 1990-2017 has caused changes in land cover and land use of the Mbarali River sub-catchment which is located in the Upper Great Ruaha Sub basin, Tanzania. This has affected the magnitude of the surface runoff, total water yield and the groundwater flow. This study assesses the impacts of the land cover and land use changes on the stream flows and hydrological water balance components (surface runoff, water yield, percolation and actual evapotranspiration). The land use and land cover (LULC) maps for three window period snapshots, 1990, 2006 and 2017 were created from Landsat TM and OLI_TIRS with the help of QGIS version 2.6. Supervised classification was used to generate LULC maps using the Maximum Likelihood Algorithm and Kappa statistics for assessment of accuracy. SWAT was set up and run to simulate stream flows and hydrological water balance components. The assessment of the impacts of land use and land cover changes on stream flows and hydrological water balance component was performed by comparing hydrological parameters simulated by SWAT using land use scenarios of 2006 and 2017 against the baseline land use scenario of 1990. Accuracy of LULC classification was good with Kappa statistics ranging between 0.9 and 0.99. There was a drastic increase in areal coverage of cultivated land, for periods 1990-2006 (5.84%) and 2006-2017 (12.05%) compared to other LULC. During 2006 and 2017 surface runoff increased by 4% and 9% respectively; however, water yield increased by only 0.5% compared to 1990 baseline period. This was attributed to increased proportion of cultivated land in the sub-catchment which has a high curve number (59.60) that indicates a higher runoff response and low infiltration rate.
Land Use/Cover Change and Its Influence on the Evapotranspiration in Taoer River Basin

LIU Qiang,HE Yan,CUI Bao-shan,

资源科学 , 2007,
Abstract: Under the influence of the global change and human activity,the water cycle shows two-dimensional hydrological characteristic in the watershed.The evapotranspiration is one of the key taches of the water cycle,which embodiments the balance of the substance,energy and the information system.The evapotranspiration is closely related to the land use and land cover change.In this paper,the authors first give the dynamic characteristics of the land use and land cover change;and then,the tempo-spatial characteristics of the potential evapotranspiration by means of the Penman-Monteith equation.By interpreting Landsat TM images,dynamic information of land use in Taoer river basin in 1986,1996 and 2000 is obtained.The area of paddy field increased most,with a rate of(5 425.71) hm~2 per year,then the glebe and saline-alkali field followed,with a ratecof(3 983.56) hm~2 per year and(2 028.35) ha per year,respectively.The area of grassland and water decreased most,with a rate of(-8 571.30) hm~2 per year and(-3 952.25) hm~2 per year,respectively.Using Penman-Monteith equation,we get the evapotranspiration of Taoer river basin in growing season.Then, in the environment of ARC/INFO 8.3,crop potential evapotranspiraiton is obtained based on the analyses of land use.Monthly crop potential evapotranspiraiton shows as an inverse "U" curve in a year,and reaches its maximum in July.Yearly totals show an increment in 15 years,from 455 mm in 1986,507 mm in 1996 to 571 mm in 2000.Generally evapotranspiration increased obviously along the river from upper reach to lower reach,and its high values distribute in low plain of lower reach every year.Hemeroby in Taoer river basin is-0.0327 in 1986,-0.0122 in 1996 and 0.0394 in 2000.Hemeroby shows that the land use and land cover change in this region has amplified the effect of climatic change and reduced the regulation of land use and land cover pattern on evapotranspiration.Locally increasing evapotranspiration intensified soil salinization and induced a series of eco-environmental problems.
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