Effects Of Land Cover Change Research Articles

Tracking the global flows of atmospheric moisture and associated uncertainties

Abstract. Many processes in hydrology and Earth system science relate to continental moisture recycling, the contribution of terrestrial evaporation to precipitation. For example, the effects of land-cover changes on regional rainfall regimes depend on this process. To study moisture recycling, a range of moisture-tracking models are in use that are forced with output from atmospheric models but differ in various ways. They can be Eulerian (grid-based) or Lagrangian (trajectory-based), have two or three spatial dimensions, and rely on a range of other assumptions. Which model is most suitable depends not only on the purpose of the study but also on the quality and resolution of the data with which it is forced. Recently, the high-resolution ERA5 reanalysis data set has become the state of the art, paving the way for a new generation of moisture-tracking models. However, it is unclear how the new data can best be used to obtain accurate estimates of atmospheric moisture flows. Here we develop a set of moisture-tracking models forced with ERA5 data and systematically test their performance regarding continental evaporation recycling ratio, distances of moisture flows, and “footprints” of evaporation from seven point sources across the globe. We report simulation times to assess possible trade-offs between accuracy and speed. Three-dimensional Lagrangian models were most accurate and ran faster than Eulerian versions for tracking water from single grid cells. The rate of vertical mixing of moisture in the atmosphere was the greatest source of uncertainty in moisture tracking. We conclude that the recently improved resolution of atmospheric reanalysis data allows for more accurate moisture tracking results in a Lagrangian setting, but that considerable uncertainty regarding turbulent mixing remains. We present an efficient Lagrangian method to track atmospheric moisture flows from any location globally using ERA5 reanalysis data and make the code for this model, which we call UTrack-atmospheric-moisture, publicly available.

Impact of Land Use/Land Cover Change on Reservoir Sedimentation: The Case of Ribb Dam Reservoir, Lake Tana Sub Basin, Ethiopia

The land and water resources of the Lake Tana Sub Basin basin is in danger due to soil erosion, sediment transport, land degradation and storage capacity reduction. There is a need for sediment transport research of this basin that can improve catchment’s management programs.This study assesses the impact of land use and land cover change effects on reservoir sedimentation using SWAT model in Upper Ribb watershed. The land use and land cover change analyses for three different years of 1973, 1995 and 2016 were performed using ERDAS Imagine 2014 which was in turn used for estimation of sediment yield. In this study the bush/shrub land were changed to grazing and cultivated land. An increase of cultivated land by 29.947% over 43 years (1973 – 2016) period resulted in an increase of sediment yield by 343.25 t/km 2 /year respectively. Model calibration and validation for sediment yield were done at Abo Bahir. The performance of the model was also checked at this station. Both the monthly calibration and validation results showed good match between measured and simulated sediment yield data with the coefficient of determination (R 2 ) of 0.857, Nash-Sutcliffe efficiency (NSE) 0.832 for the calibration, and R 2 of 0.834 and NSE of 0.796 of the validation period.Spatial sediment distribution was done using the calibrated and validated sediment yield results of 2016 land use. High potential source areas were found at north-eastern part of the watershed which was a combined result of highly cultivated land, steep slope and erosive soil (Eutric Leptosols). Therefore, these critical sub- watersheds should preserve from further exposing of soil erosion through either forest resource development or uncultivated the steeply slope areas. And also the increasing/expanding bushes/shrub land should also be encouraged in the watershed first by applying for those most erosion prone sub watersheds. Keywords: Upper Ribb watershed, SWAT, sediment yield, spatial sediment distribution. DOI: 10.7176/JEES/10-3-02 Publication date: March 31 st 2020

Impact of Land Use/Land Cover Change on Reservoir Sedimentation: The Case of Ribb Dam Reservoir, Lake Tana Sub Basin, Ethiopia

The land and water resources of the Lake Tana Sub Basin basin is in danger due to soil erosion, sediment transport, land degradation and storage capacity reduction. There is a need for sediment transport research of this basin that can improve catchment’s management programs. This study assesses the impact of land use and land cover change effects on reservoir sedimentation using SWAT model in Upper Ribb watershed. The land use and land cover change analyses for three different years of 1973, 1995 and 2016 were performed using ERDAS Imagine 2014 which was in turn used for estimation of sediment yield. In this study the bush/shrub land were changed to grazing and cultivated land. An increase of cultivated land by 29.947% over 43 years (1973 – 2016) period resulted in an increase of sediment yield by 343.25 t/km 2 /year respectively. Model calibration and validation for sediment yield were done at Abo Bahir. The performance of the model was also checked at this station. Both the monthly calibration and validation results showed good match between measured and simulated sediment yield data with the coefficient of determination (R 2 ) of 0.857, Nash-Sutcliffe efficiency (NSE) 0.832 for the calibration, and R 2 of 0.834 and NSE of 0.796 of the validation period. Spatial sediment distribution was done using the calibrated and validated sediment yield results of 2016 land use. High potential source areas were found at north-eastern part of the watershed which was a combined result of highly cultivated land, steep slope and erosive soil (Eutric Leptosols). Therefore, these critical sub- watersheds should preserve from further exposing of soil erosion through either forest resource development or uncultivated the steeply slope areas. And also the increasing/expanding bushes/shrub land should also be encouraged in the watershed first by applying for those most erosion prone sub watersheds. Keywords : Upper Ribb watershed, SWAT, sediment yield, spatial sediment distribution. DOI: 10.7176/CER/12-5-01 Publication date: May 31 st 2020

The impact of land-use/land cover changes on water balance of the heterogeneous Buzi sub-catchment, Zimbabwe

The nature of interactions between ecological, physical and hydrological characteristics that determine the effects of land cover change on surface and sub-surface hydrology is not well understood in both natural and disturbed environments. The spatiotemporal dynamics of water fluxes and their relationship with land cover changes between 2009 and 2017 in the headwater Buzi sub-catchment in Zimbabwe is evaluated. To achieve this, land cover dynamics for the area under study were characterised from the 30 m Landsat data, using the eXtreme Gradient Boosting (XGBoost) algorithm. After the land cover classification, the key water balance components namely; interception, transpiration and evapotranspiration (ET) contributions for each class in 2009 and 2017 were estimated. Image classification of Landsat data achieved good overall accuracies above 80% for the two periods. Results showed that the percentage of the plantation land cover types decreased slightly between 2009 (25.4%) and 2017 (22.5%). Partitioning the annual interception, transpiration and ET according to land cover classes showed that the highest amounts of ET in the basin were from plantation where land cover types with tea had the highest interception, transpiration and ET in the catchment. Higher ET, interception and transpiration were observed in the eastern parts of the catchment. At catchment level, results show that 2017 had a higher water balance than 2009, which was partly explained by the decrease in plantation cover type.

Effects of land cover change on atmospheric and storm surge modeling during typhoon event

Understanding the role of land cover changes on climate and hydrology during typhoon events is vital for coastal hazard mitigation, prevention, as well as the regulation of land cover. To investigate the effects of land cover changes, simulation studies using the WRF model to calculate the meteorological field combined with the Delft3D-FLOW model capable of accurately simulating storm surges were conducted. The accuracy of this modeling approach is guaranteed since the models were validated against available in-situ and satellite measurements during typhoon Rammasun (2014) period. Through comparing simulation results obtained with the MODIS 2001 and the GlobCover 2009 land cover data scenarios, it is found that land cover changes in the study region exert an apparent influence on the atmospheric and storm surge simulations. Notable disagreements exist between the selected two land cover data. Different types of land cover have disparate physical properties, such as roughness length that alters the typhoon-induced wind field simulation results, thus resulting in changes in storm surge simulation results. Determining the impact of land cover changes on atmosphere and storm surge provides clearer insight into the land cover impacts, which is of great benefit to the atmospheric and storm surge models improvement.

Thermal unmixing based downscaling for fine resolution diurnal land surface temperature analysis

Due to the limitation in the availability of airborne imagery data that are high in both spatial and temporal resolution, land surface temperature (LST) dense in both space and time can only be obtained through downscaling of frequently acquired LST with coarse resolution. Many conventional downscaling techniques are only feasible in an ideal situation, where land surface factors as LST predictors are continuously available for downscaling the LST. These techniques are also applied only at large scales ignoring sub-regional variations. Based upon unmixing based approaches, this study presents an LST downscaling workflow, where only the coarse resolution of 1 km LST image at the prediction time is required. The conceptual backbone of the study is assuming that the LST patterns are governed by thermal behaviors of a fixed set of temperature sensitive land surface components. In operation, the study focuses on central Netherlands covering an area of 90 × 90 km. The MODIS and Landsat imagery acquired simultaneously are used as a coarse-fine resolution pair to derive downscaling mechanism which is then applied to coarse imagery at a time with missing fine resolution imagery. First, an optimal number of thermal components are extracted at fine resolution through the application of the non-negative matrix factorization (NMF). These components are assumed to possess unique temperature change patterns caused by combined effects of land cover change, radiance change, or both. Given the LST change and thermal components at coarse resolution, the LST change load of each component can then be obtained at the coarse resolution by solving a system of linear equations encoding thermal component-LST relationship. Such LST change load of thermal components is further unmixed to fine resolution and linearly weighted by the component distribution at fine resolution to obtain the fine resolution LST change. During the process, the coarse LST data is used directly without any resampling practice as shown in previous studies. Thus the technique is less time consuming even with a large downscaling factor of 30. The downscaled fine resolution LST represents an R-squared of over 0.7 outperforming classic downscaling techniques. The downscaled LST differentiates temperature over major land types and captures both seasonal and diurnal LST dynamics.

Effects of land cover change on hydrological responses of a large-scale basin in Brazilian Amazon

Conversion of tropical forests is considered a major environmental problem that has impacts on climate and hydrological regimes. The objective of this study was to analyse the effects of land cover changes on rainfall and streamflow of a large-scale catchment in the Brazilian Amazon. Using long time-series data, the statistical z-tests and t-tests were performed to verify the hydrological differences between two periods. The results confirmed an increase with high statistical significance in streamflow (p = 7 94E-05) and no significant variation in rainfall. The channel flow also showed an increase with high statistical significance during the high-flow and the low-flow seasons. The main achievement here is that the most previous studies that pointed to similar conclusions were developed through small catchments, controlled experiments, or theoretical hydrological models. Studies based on real data of large-scale basins like studies based on real data of large-scale basins mostly failed to detect the same trends.

The Effect of Land Cover Changes on Land Surface Temperature in Tangerang Selatan on 2005, 2008, 2013, and 2018

South Tangerang is the city with the highest population growth in Banten Province and one of the cities with the highest economic growth rate in Indonesia. Its causes higher land demand and forces land use/land cover change from non built-up area into built-up area in South Tangerang. Buildings and asphalt in urban areas contribute greatly to high surface temperatures. This study aims to look at changes in land cover that occurred in South Tangerang in 2005, 2008, 2013 and 2018, and the effect on land surface temperature. The data used in this study are Landsat TM (2005 and 2008) and Landsat OLI-TIRS images (2013 and 2018) were used to generate land cover, building density, vegetation density, and land surface temperature. This study uses the decision tree method to generate land cover classification, Normalized Difference Built-Up/Barren Index (NDBI), Normalized Difference Vegetation Index (NDVI), and Land Surface Temperature (LST). The results show that changes in land cover into built-up land are increasing land surface temperature around 0.4 - 0.70C each year in South Tangerang. Land surface temperature has a positive correlation with building density, and a negative correlation with vegetation density.

Modeling the Impact of Land Cover Changes on Soil Erosion Estimation in Yewa North and Yewa South, Ogun State, Nigeria

Soil erosion is becoming a serious problem in some communities in Yewa North and Yewa South because of rapid land use developments. This study was carried out to analyses the landcover change effects on soil erosion to determine the extent and trend of changes in the study area; estimate and characterize soil loss, and comparing the annual soil loss at different spatial scales. The extent and trend of changes in the landcover were estimated using Landsat Satellite Imageries for the year 2002 and 2017. RUSLE model was used to estimate soil loss and was characterized based on the expert description for tolerable soil loss concept. The results revealed the built-up area showed a consistent increase over time, from 349.5km2 in 2002 to 592km2 in 2017 of the total area. The vegetation covered about 933.4km2 in 2002 but decreased to 509km2 in 2017. Similarly, the area covered by bare ground increased from 243.7km2 in 2002 to 620.4 km2 in 2017 but the waterbody increased from 0.29km2 in 2002 to 0.72km2 in 2017. The areas covered by agriculture also decreased from 1088.5km2 in 2002 to 894km2 in 2017. The estimated soil loss values ranged from 0 – 420,276 t ha-1 yr-1 with the mean of 231 and standard deviation 2272 in 2002 while the soil loss estimated in 2017 ranged from 0 – 186,920 t ha/ yr. with the mean of 220 and the standard deviation 1312.3. Comparatively, low erosion is observed in a total area of 45.5% in 2002 and 44.4% in 2017 while extremely severe erosion is observed in a total area of 29.8% in 2002 and 34.3% in 2017 in the study area which matches the actual bareground and agricultural land which can be attributed to change in C and P factors. The study recommended that enlightenment and awareness of erosion control should include land use habit of the people in the agricultural practice and care of vegetation

Can We Detect Changes in Amazon Forest Structure Using Measurements of the Isotopic Composition of Precipitation?

AbstractLarge‐scale (>500 km) spatial gradients of precipitation oxygen isotope ratios (δ18Op) hold information about the hydrological cycle. They result from the interplay between rainout and evapotranspiration along air‐parcel paths, but these counteracting effects are difficult to disentangle, complicating quantification of the effect of land cover change on δ18Op. We show that disentangling can qualitatively be achieved using climate model simulations with a land‐derived precipitation tracer for tropical South America. We then either vary land cover as observed since 1870 or replace Amazon forests with bare land to determine the resulting signals. Our results indicate that effects of historically changing land cover on annual mean δ18O isotope‐ratio gradients are small and unlikely detectable, although there is a noticeable signal during the dry season. Furthermore, the effect of changes in water recycling on Amazon δ18Op in paleo‐records may have been overestimated and need reinterpretation.

ANALYZING THE EFFECTS OF LAND COVER CHANGE ON SURFACE TEMPERATURE IN MOUNT MAKILING FOREST RESERVE (MMFR) AND ITS NEIGHBORING MUNICIPALITIES USING LANDSAT DATA

Abstract. Land Surface Temperature (LST) is said to be affected by frequent changes in the land cover. Over the years, the immediate environs of Mount Makiling Forest Reserve (MMFR) have experienced such kind of change due to rapid economic growth of the area that also led to the expansion of urban centers. The study utilized Landsat imageries to determine the possible effects of land cover change on surface temperature using the integration of remote sensing and GIS technologies. Initially, the multispectral bands were radiometrically corrected using Dark Object Subtraction (DOS) while the thermal bands were corrected using Land Surface Emissivity (LSE). After these corrections were applied, the images were classified using supervised image classification technique where seven land cover types have been identified. The classified images were then validated using 200 reference data and this revealed an overall accuracy of 87.5% and 86.0% for the May 2003 and July 2015 images, respectively. Results showed that changes in land cover resulted to a significant change in Land Surface Temperature (LST). The LST in 2003 (16.49°C – 40.44°C) was found higher than that of 2015 which was observed between 13.35°C and 33.83°C only. The reason behind this is the increase in green spaces from 2003 to 2015. Among the major land cover types, forest lands exhibited the lowest mean surface temperature for both years having 27.27°C in 2003 and 21.35°C in 2015 while built-up areas had the highest surface temperature having 32.60°C in 2003 and 26.00°C in 2015.

Study on the Effects of Landcover Changes on Surface Albedo and Surface Temperature in Bangladesh Using Remote Sensing and GIS

Dynamic changes in Earth’s land cover characteristics and associated temporally evolving biophysical surface properties, as well as their ultimate impacts on surface radiative (surface albedo) and climatic properties (land surface temperature), have been studied. The study area includes a part of southwestern Bangladesh covering a period of about twenty years from 1988 – 2011. The widely used Surface Energy Balance Algorithm for Land (SEBAL) has been applied in conjunction with satellite-derived radiative measurements. Relatively important land use types such as water, soil, sand, settlement, shrimp farm, forest and agricultural crop have been considered. Feature type conversion of parameters i.e Normalized Difference of Vegetation Index (NDVI), surface albedo and land surface temperature have been noticed over the area under the present study. The highest surface albedo as well as surface temperature value has been noticed over the sandy area. Analysis revealed increases of surface temperature by about 1 °C and 3 °C for land cover conversion from (i) crop to settlement and (ii) water to soil, respectively. All other categories of landcover conversion generally experience decreases in surface temperature. Spatial vegetation coverage and amount of soil moisture play a dominant role in the radiative as well as climatic properties.

Vegetation encroachment ratios in regulated and non-regulated Mediterranean rivers (Spain): An exploratory overview

Vegetation encroachment is an expected response of rivers to a decrease in their flow variability and flood magnitude and frequency. It frequently occurs together with channel narrowing and a decrease in braiding, both of which are likely associated with different human alterations but most frequently with river damming. Vegetation encroachment ratios display a wide range of values according to local hydrologic and geomorphic contexts and dam operation management, and thus, they are very site specific. As vegetation interacts with fluvial processes, understanding the mechanisms that promote encroachment is important for predicting river trends and designing proper management and restoration measures. Our research aimed to explore the causal relationship between flow regulation and vegetation encroachment in Mediterranean rivers in Spain. We quantified vegetation encroachment and channel changes over the last 50 years in 13 river reaches, 5 of which corresponded to non-regulated rivers and 8 of which were located in rivers regulated by large dams. We analysed aerial orthophotographs from 1956, 1977 and 2011 or later up to 2014, according to image availability. We considered 1956 conditions as a reference and quantified ratios of changes in riparian vegetation cover, active channel width and braiding index over two periods, 1956–1977 and 1978–2011. We quantified the changes in the flow regime and clustered rivers according to their hydrological pattern, looking for potential hydrological drivers of the observed changes over time.Vegetation encroachment, channel narrowing and braiding decreases occurred in all the studied rivers. Significant differences in annual ratios between the studied periods were found for both vegetation encroachment and channel narrowing, but no statistically significant differences were found between the regulated and non-regulated rivers or between the hydrological river groups previously clustered by flow variables. After discussing existing literature, we suggest a multi-scale approach to understanding river changes over time, encompassing larger historical perspectives. We hypothesize a generalized hydrologic decline since the beginning of the 20th century affecting rivers at the broad-regional scale would be overlapping the effects of land cover changes (i.e., renaturalization) at the catchment scale in reducing flood intensity and sediment supply. River damming would reinforce these patterns at river segment scale, in turn overlapping the influence of local geomorphic and ecological features. This hypothesis, which should be tested by further research, may explain the constancy of encroachment and channel narrowing regionally reported but with a wide variety of change ratios, determining converging trajectories of Iberian rivers that have also been found in other regions.

Land cover change effects on land surface temperature trends in an African urbanizing dryland region

Land use-land cover (LULC) association with land surface temperature (LST) is well known. Knowledge about land change effects on LST in urbanizing African drylands is very limited. We examined LST and vegetation variations in semi-arid Gaborone (Botswana's capital) using MODIS daytime and night-time LST (DNLST), and Normalized Difference Vegetation Index (NDVI) between 2000 and 2018. Significant land transitions were identified in the land cover change map using Change Vector Analysis of Landsat-based biophysical indices of vegetation, water and bare soil. Artificial surface and tree-covered areas were net gaining categories, whereas cropland and grassland were net losing categories. Detailed profiling of DNLST trends and breakpoints was conducted in five relatively homogenous sites representing land cover/transitions. Increasing NDVI and DNLST trends found were significant. Per class, LST change at daytime and night-time are as follows: built-up areas (1.8 K, 2.2 K), Gaborone dam (5.7 K, 0.2 K), settlement expansion areas (4.6 K, 2.2 K), and rural settlement (2.0 K, 1.5 K). The cooling effect of irrigation on daytime LST was higher than night-time LST as daytime LST trend as low as −0.4 K was found in areas of irrigated croplands. Validation with synoptic station temperature data and dam water levels provides empirical evidence that MODIS gave credible DNLST estimates in this urbanizing dryland area. Our results also suggest the role of climate variability in urbanizing drylands alongside land cover change in controlling the LST. Regardless, coupling DNLST and land cover changes can provide useful information for spatial planning of drylands to create smart cities that are resilient to climate change.

Floodplain land cover affects biomass distribution of fish functional diversity in the Amazon River

Land-cover change often shifts the distribution of biomass in animal communities. However, the effects of land-cover changes on functional diversity remain poorly understood for many organisms and ecosystems, particularly, for floodplains. We hypothesize that the biomass distribution of fish functional diversity in floodplains is associated with land cover, which would imply that fish traits affect behavioral and/or demographic responses to gradients of land cover. Using data from surveys of 462 habitats covering a range of land-cover conditions in the Amazon River floodplain, we fitted statistical models to explain landscape-scale variation in functional diversity and biomass of all fish species as well as subsets of species possessing different functional traits. Forest cover was positively associated with fish biomass and the strength of this relationship varied according to functional groups defined by life history, trophic, migration, and swimming-performance/microhabitat-use traits. Forty-two percent of the functional groups, including those inferred to have enhanced feeding opportunities, growth, and/or reproductive success within forested habitats, had greater biomass where forest cover was greater. Conversely, the biomass of other functional groups, including habitat generalists and those that directly exploit autochthonous food resources, did not vary significantly in relation to forest cover. The niche space occupied by local assemblages (functional richness) and dispersion in trait abundances (functional dispersion) tended to increase with forest cover. Our study supports the expectation that deforestation in the Amazon River floodplain affects not only fish biomass but also functional diversity, with some functional groups being particularly vulnerable.

Effects of landcover changes on net primary production (NPP)-based exergy in south-central of Chile

A new indicator for the accounting effect of landcover is defined based on the integration of thermodynamics (exergy analysis) and ecology (net primary production (NPP)). The indicator NPPEX allows quantifying and assessing the impacts of landuse changes, in spatial and temporally dimensions. This study is focused on the effect of landuse changes on NPP-based exergy for the south-central of Chile from 2000 to 2014. The exergy-based spatially characterization factor (NPPEX) was estimated based on the time series of NPP extracted from MODIS and exergy conversion factor. Finally, the dynamic of NPPEX changes by the transition of each landuse type was studied for identifying the driver force influencing on biomass productivity. Results confirmed the important influence of forestry policy on land use changes, in particular, the forest transitions during the two last decade, which exhibit a cover increase of 28% between 1994 and 2014 established mainly on land destined to crops, native forest, and shrubs. In consequences, the highest land efficiency (NPPEX) was obtained for exotic tree plantations (88.25–91.4 MJex m−2yr−1) during all studied period, due to high carbon stock per square meter associated to its intensive forest management. From the transition of landcover changes point of view, there was produced a positive effect on NPPEX, being the exotic tree plantation expansion the main driver of gains of NPPEX. Nevertheless, this expansion has carried out severe local environmental impacts (i.e., ecosystem fragmentation, biodiversity loss, topsoil compaction, losses of Biobío Basin's morpho-sedimentary regulation capacity, etc.).

Effects of land cover changes and slope gradient on soil quality in the Gumara watershed, Lake Tana basin of North\u2013West Ethiopia

This study evaluated land cover change and slope gradient on selected soil quality parameters in the Gumara watershed, northwestern Ethiopia. 36 soil samples were collected from 0- to 20-cm depth under four land cover types across three slope gradients. The collected soil samples were analyzed for selected soil quality parameters. Result indicated that the bulk density of the soil is different (P < 0.001) in the watershed because of land cover change and slope gradient. Cultivated land and steeper slopes have the highest bulk density and lowest total porosity. On the other hand, the forestland and gentler slopes have lowest bulk density and high total porosity. Intensive cultivation accompanied by continuous conversion of forestland to cultivated land caused high bulk density and low total porosity. Cation exchange capacity, exchangeable magnesium total nitrogen, available phosphorus and potassium negatively correlated with slope gradient. Conversion of forestland to cultivated land contributed to changes in pH (P < 0.05) exchangeable calcium (P < 0.01), potassium (P < 0.001), available phosphorus (P < 0.01) and nitrogen (P < 0.01) content. The soil degradation index results showed that soil organic carbon, nitrogen, available phosphorus and exchangeable potassium contents declined and bulk density increased because of the land cover change. This negative effect on agricultural development and environmental health of the watershed makes an integrated land resource management approach vital for sustaining agricultural productivity and the environment health of the Gumara watershed.

Correction to: Modeling the effects of land cover change on sediment concentrations in a gold-mined Amazonian basin

The article which was recently published contained error. The second given names “Andrade” and “de Lucia” were captured as particles. Given in this article is the correct naming of authors.

Modeling the effects of land cover change on sediment concentrations in a gold-mined Amazonian basin

Land use/land cover change (LUCC) combined with gold mining activity (GMA) have reportedly affected the water quality of Amazonian rivers by intensifying surface soil erosion and increasing rivers’ sediment concentration (SC). However, the role of LUCC on river siltation in comparison to that caused by GMA has not been assessed, and predictions of SC in the rivers accounting for future LUCC are scarce. This study applied a sediment modeling approach on Crepori Basin, located at eastern Amazon Basin, to simulate the impacts of past and future LUCC on SC in the river, comparing their impacts to those caused by GMA. Between 1973 and 2012, the expansion of deforested areas in the region had increased sheet erosion-driven SC in the river, especially during the high-water season, by up to 73.3%. LUCC projections for 2050 suggest future increases in sheet erosion-driven SC during the high-water season by more than three times of that caused by the land cover scenario of 1998–2012. Comparison between SC driven by sheet erosion to that caused by GMA has also shown that during the high-water and the low-water seasons, respectively, only about 14% and 6% of the total SC in the Crepori River resulted from laminar soil erosion, with the remaining proportion resulting from GMA.

Impact of Land Use/Land Cover Change on Hydrology of the Catchment: The Case of Upper Ribb Catchment, Lake Tana Sub Basin, Ethiopia

Land use/land cover dynamics has been recognized as one of the factors responsible for altering the hydrologic response of watersheds. Various extent of water resources projects planning and implementation will require knowledge of these changes on catchment hydrology. This study assesses the impact of land use and land cover change effects on stream flow using SWAT model in Upper Ribb Catchment. The analysis of stream flow was done for three different years of 1973, 1995 and 2016 using SWAT model. During the study period of over 43 years (1973 – 2016) stream flow was increased to 6.143m 3 /s due to an increase of cultivated land by 29.947%. Model calibration and validation for stream flow were done at Upper Ribb gauging station. The performance of the model was also checked at this station. Both the monthly calibration and validation results showed good match between measured and simulated stream flow data with the coefficient of determination (R 2 ) of 0.85, Nash-Sutcliffe efficiency (NSE) of 0.824 for the calibration, and R 2 of 0.829 and NSE of 0.814 of the validation period. Keywords : Upper Ribb, Catchment, SWAT, stream flow. DOI : 10.7176/JEES/9-6-02 Publication date :June 30 th 2019