scholarly journals Linking Changes in Land Cover and Land Use of the Lower Mekong Basin to Instream Nitrate and Total Suspended Solids Variations

2020 ◽  
Vol 12 (7) ◽  
pp. 2992 ◽  
Author(s):  
Kongmeng Ly ◽  
Graciela Metternicht ◽  
Lucy Marshall
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Land Cover ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Mekong River ◽  
Forest Land ◽  
Lulc Changes ◽  
Correlation Analyses ◽  
Forest Land Cover

Population growth and economic development are driving changes in land use/land cover (LULC) of the transboundary Lower Mekong River Basin (LMB), posing a serious threat to the integrity of the river system. Using data collected on a monthly basis over 30 years (1985–2015) at 14 stations located along the Lower Mekong river, this study explores whether spatiotemporal relationships exist between LULC changes and instream concentrations of total suspended solids (TSS) and nitrate—as proxies of water quality. The results show seasonal influences where temporal patterns of instream TSS and nitrate concentrations mirror patterns detected for discharge. Changes in LULC influenced instream TSS and nitrate levels differently over time and space. The seasonal Mann–Kendall (SMK) confirmed significant reduction of instream TSS concentrations at six stations (p < 0.05), while nitrate levels increased at five stations (p < 0.05), predominantly in stations located in the upper section of the basin where forest areas and mountainous topography dominate the landscape. Temporal correlation analyses point to the conversion of grassland (r = −0.61, p < 0.01) to paddy fields (r = 0.63, p < 0.01) and urban areas (r = 0.44, p < 0.05) as the changes in LULC that mostly impact instream nitrate contents. The reduction of TSS appears influenced by increased forest land cover (r = −0.72, p < 0.01) and by the development and operation of hydropower projects in the upper Mekong River. Spatial correlation analyses showed positive associations between forest land cover and instream concentrations of TSS (r = 0.64, p = 0.01) and nitrate (r = 0.54, p < 0.05), indicating that this type of LULC was heavily disturbed and harvested, resulting in soil erosion and runoff of nitrate rich sediment during the Wet season. Our results show that enhanced understanding of how LULC changes influence instream water quality at spatial and temporal scales is vital for assessing potential impacts of future land and water resource development on freshwater resources of the LMB.

scholarly journals Land Use Land Cover Changes and Their Effects on Surface Air Temperature in Myanmar and Thailand

2021 ◽  
Vol 13 (19) ◽  
pp. 10942
Author(s):  
Khun La Yaung ◽  
Amnat Chidthaisong ◽  
Atsamon Limsakul ◽  
Pariwate Varnakovida ◽  
Can Trong Nguyen
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Cover ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Forest Conversion ◽  
Land Use Land Cover ◽  
Forest Land ◽  
Lulc Changes ◽  
Average Maximum

Land use land cover (LULC) change is one of the main drivers contributing to global climate change. It alters surface hydrology and energy balance between the land surface and atmosphere. However, its impacts on surface air temperature have not been well understood in a dynamic region of LULC changes like Southeast Asia (SEA). This study quantitatively examined the contribution of LULC changes to temperature trends in Myanmar and Thailand as the typical parts of SEA during 1990–2019 using the “observation minus reanalysis” (OMR) method. Overall, the average maximum, mean, and minimum temperatures obtained from OMR trends indicate significant warming trends of 0.17 °C/10a, 0.20 °C/10a, and 0.42 °C/10a, respectively. The rates of minimum temperature increase were larger than maximum and mean temperatures. The decreases of forest land and cropland, and the expansions of settlements land fractions were strongly correlated with the observed warming trends. It was found that the effects of forest land converted to settlement land on warming were higher than forest conversion to cropland. A comprehensive discussion on this study could provide scientific information for the future development of more sustainable land use planning to mitigate and adapt to climate change at the local and national levels.

scholarly journals Multi-Scale Analysis of the Dependence of Water Quality on Land Use Using Linear and Mixed Models

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2618
Author(s):  
Johann Alexander Vera Mercado ◽  
Bernard Engel
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Suspended Solids ◽  
Spatial Scales ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Quality Parameters ◽  
Total Kjeldahl Nitrogen ◽  
Nitrate And Nitrite ◽  
Kjeldahl Nitrogen

Land use influences water quality in streams at different spatial scales and varies in time and space. Water quality has long been associated with agricultural and urban land uses in catchments. The effects of developed, forest, pasture, and agricultural land use on nitrogen, nitrate, and nitrite (NNN); total phosphorus (TP); total suspended solids (TSS); chemical oxygen demand (COD); dissolved oxygen (DO) and total Kjeldahl nitrogen (TKN) concentrations and their sensitivity were quantified to spatial pattern differences. The linear mixed modeling framework was used to examine the importance of spatial extent on models with water quality parameters as the response variable and land use types as the predictor variable. The results indicated that land use categories on different water quality parameters were significant and dependent on the selected spatial scales. Land use exhibited a strong association with total phosphorus and total suspended solids for close reach distances. Phosphorus is not highly soluble, and it binds strongly to fine soil particles, which are transported by water via runoff. Nitrogen, nitrate, and nitrite, dissolved oxygen, chemical oxygen demand, and total Kjeldahl nitrogen concentrations were better predicted for further reach distances, such as 45 or 50 km, where the best model of nitrogen, nitrate, and nitrite is consistent with the high mobility of NO3−.

scholarly journals Analysis and Prediction of Land Use/land Cover Changes and Driving Forces by Using GIS and Remote Sensing in the Coka Watershed, Southern Ethiopia

2021 ◽  
Author(s):  
Tadele Buraka ◽  
Eyasu Elias ◽  
Alemu Lelago
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Water Body ◽  
Landscape Planning ◽  
Rural Settlement ◽  
Annual Rate ◽  
Southern Ethiopia ◽  
Forest Land ◽  
Lulc Changes ◽  
Bare Land

Abstract Land use and land cover (LULC) is among fundamental environmental and ecological factors for monitoring, resource management, police making, planning and facilitating the development of strategies to balance conservation, development pressures, and conflicting uses. This study aimed at analyzing LULC changes that have occurred during 1988–2018 and its prediction for 2040–2060 period in Coka watershed, southern Ethiopia. LULC changes were analyzed using geographic information system and predicted by CA-Markov model. Cultivated and rural settlement land, bare land, built up area and water body have increased at an annual rate of 23.1, 2.2, 0.8 and 1.1 ha/year but forest land, bushland and grassland have decreased at an annual rate of 14.4, 4.1 and 8.7 ha/year, respectively. It is projected that cultivated and rural settlement land, bare land, built up area and water body will expand but forest land, grassland and bushland will decrease. Expansion of agriculture and deforestation showed increasing trend on both previous and predicted LULC changes with upcoming expansion of bare land and eucalyptus tree plantation due to major driving factor of population growth. This study highlights the need for well integrated landscape planning, reliable predictions for future LULC and to reduce the deterioration of environment.

scholarly journals The Evaluation of Dissolved Oxygen (DO), Total Suspended Solids (TSS) and Suspended Sediment Concentration (SSC) in Terengganu River, Malaysia

2018 ◽  
Vol 7 (3.14) ◽  
pp. 44
Author(s):  
Noorjima Abd Wahab ◽  
Mohd Khairul Amri Kamarudin ◽  
Mohd Ekhwan Toriman ◽  
Frankie Marcus Ata ◽  
Hafizan Juahir ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Dissolved Oxygen ◽  
Suspended Sediment ◽  
River Basin ◽  
Suspended Solids ◽  
Suspended Sediment Concentration ◽  
Total Suspended Solids ◽  
Sediment Concentration ◽  
Quality Parameters

Terengganu River Basin is situated in the north eastern coastal region of Peninsular Malaysia. 29 sampling stations were selected. The water quality parameters were measured such as Dissolved Oxygen (DO), Total Suspended Solids (TSS) and Suspended Sediment Concentration (SSC). Results showed that the range of DO (2.11 mg/L – 8.07 mg/L), TSS (0.4 mg/L – 128.2 mg/L) and SSC (0.07 mg/L – 25.6 mg/L). The distribution of land use and land cover activities effected to the level of water quality in watersheds. The analyses of variance (ANOVA) was applied and provide a better understanding for the complex relationships among water quality parameters. Graphical data helps a better view of the overall analysis to appoint sources of pollutants to their effect. Terengganu River Basin is a shallow and has a sensitive ecosystem that responds to the land use changes and development activities of its surroundings. Water quality analysis showed that TSS and SSC were higher in the dry season but DO were higher in the wet season. Overall, the water in the Terengganu River Basin classified slightly contaminated especially the main sources of pollutants were possibly waste products and waste from development activities such as sand mining, farming, residential and agricultural.  

scholarly journals An analysis of forest land use, forest land cover and change at policy-relevant scales

2013 ◽  
Vol 87 (2) ◽  
pp. 267-276 ◽  
Author(s):  
J. W. Coulston ◽  
G. A. Reams ◽  
D. N. Wear ◽  
C. K. Brewer
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Forest Land ◽  
Forest Land Cover

scholarly journals Spatial Analysis of a Chesapeake Bay Sub-Watershed: How Land Use and Precipitation Patterns Impact Water Quality in the James River

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1592
Author(s):  
Kristina A. Delia ◽  
Christa R. Haney ◽  
Jamie L. Dyer ◽  
Varun G. Paul
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Land Cover ◽  
Chesapeake Bay ◽  
Quality Indicators ◽  
Assessment Tool ◽  
Residential Development ◽  
Forest Land ◽  
James River ◽  
Water Quality Indicators

Changes in land cover throughout the Chesapeake Bay watershed, accompanied by variability in climate patterns, can impact runoff and water quality. A study was conducted using the Soil and Water Assessment Tool (SWAT) for the James River watershed in Virginia, the southernmost tributary of the Chesapeake Bay, from 1986 to 2018, in order to evaluate factors that affect water quality in the river. This research focuses on statistical analysis of land use, precipitation, and water quality indicators. Land cover changes derived from satellite imagery and geographic information system (GIS) tools were compared with water quality parameters throughout that timeframe. Marked decreases in forest land cover were observed throughout the watershed, as well as increased residential development. Our findings suggest strong links between land cover modification, such as residential development, and degraded water quality indicators such as nitrogen, phosphorus, and sediment. In addition, we note direct improvements in water quality when forest land areas are preserved throughout the watershed.

scholarly journals Use of principal component analysis, factor analysis and discriminant analysis to evaluate spatial and temporal variations in water quality of the Mekong River

2008 ◽  
Vol 10 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Sangam Shrestha ◽  
Futaba Kazama ◽  
Takashi Nakamura
Keyword(s):  
Water Quality ◽  
Principal Component Analysis ◽  
Factor Analysis ◽  
Discriminant Analysis ◽  
Suspended Solids ◽  
Nitrate Nitrogen ◽  
Principal Component ◽  
Total Suspended Solids ◽  
Component Analysis ◽  
Mekong River

Multivariate statistical techniques, such as principal component analysis (PCA), factor analysis (FA) and discriminant analysis (DA), were applied for the evaluation of temporal/spatial variations and the interpretation of a large complex water quality dataset of the Mekong River using data sets generated during 6 years (1995–2000) of monitoring of 18 parameters (16,848 observations) at 13 different sites. The results of PCA/FA revealed that most of the variations are explained by dissolved mineral salts along the whole Mekong River and in individual stations. Discriminant analysis showed the best results for data reduction and pattern recognition during both spatial and temporal analysis. Spatial DA revealed 8 parameters (total suspended solids, calcium, sodium, alkalinity, chloride, iron, nitrate nitrogen, total phosphorus) and 12 parameters (total suspended solids, calcium, sodium, potassium, alkalinity, chloride, sulfate, iron, nitrate nitrogen, total phosphorus, silicon, dissolved oxygen) are responsible for significant variations between monitoring regions and countries, respectively. Temporal DA revealed 3 parameters (conductivity, alkalinity, nitrate nitrogen) between monitoring regions; 3 parameters (total suspended solids, conductivity, silicon) in midstream region; and 2 parameters (conductivity, silicon) in upstream, lower stream and delta region which are the most significant parameters to discriminate between the four different seasons (spring, summer, autumn, winter). Thus, this study illustrates the usefulness of principal component analysis, factor analysis and discriminant analysis for the analysis and interpretation of complex datasets and in water quality assessment, identification of pollution sources/factors, and understanding of temporal and spatial variations of water quality for effective river water quality management.

scholarly journals Integrated Approach to Quantify the Impact of Land Use and Land Cover Changes on Water Quality of Surma River, Sylhet, Bangladesh

Water ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 17
Author(s):  
Abdul Kadir ◽  
Zia Ahmed ◽  
Md. Misbah Uddin ◽  
Zhixiao Xie ◽  
Pankaj Kumar
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Land Cover ◽  
Agricultural Land ◽  
Regression Result ◽  
Barren Land ◽  
Lulc Changes ◽  
The Impact ◽  
Surma River

This study aims to assess the impacts of land use and land cover (LULC) changes on the water quality of the Surma river in Bangladesh. For this, seasonal water quality changes were assessed in comparison to the LULC changes recorded from 2010 to 2019. Obtained results from this study indicated that pH, electrical conductivity (EC), and total dissolved solids (TDS) concentrations were higher during the dry season, while dissolved oxygen (DO), 5-day biological oxygen demand (BOD5), temperature, total suspended solids (TSS), and total solids (TS) concentrations also changed with the season. The analysis of LULC changes within 1000-m buffer zones around the sampling stations revealed that agricultural and vegetation classes decreased; while built-up, waterbody and barren lands increased. Correlation analyses showed that BOD5, temperature, EC, TDS, and TSS had a significant relationship (5% level) with LULC types. The regression result indicated that BOD5 was sensitive to changing waterbody (predictors, R2 = 0.645), temperature was sensitive to changing waterbodies and agricultural land (R2 = 0.889); and EC was sensitive to built-up, vegetation, and barren land (R2 = 0.833). Waterbody, built-up, and agricultural LULC were predictors for TDS (R2 = 0.993); and waterbody, built-up, and barren LULC were predictors for TSS (R2 = 0.922). Built-up areas and waterbodies appeared to have the strongest effect on different water quality parameters. Scientific finding from this study will be vital for decision makers in developing more robust land use management plan at the local level.

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