Effects Of Land Cover Change Research Articles

Quantifying the Effect of Land-cover Change on the Endangered Farmland Green Treefrog (Zhangixalus arvalis) in an Agricultural Landscape: Implications for Conservation.

Habitat loss and fragmentation have a significant negative effect on amphibian species, particularly those with specialized habitat requirements. The endangered farmland green treefrog (Zhangixalus arvalis) primarily inhabits woodlands of agricultural landscapes in central Taiwan. Recently, due to increased demands for pineapple products, many woodlands, particularly bamboo plantations, were converted to pineapple fields. This study aimed to quantify the effect of habitat loss and fragmentation on Z. arvalis due to changes in land cover in an agricultural landscape. The study area contained 34,243 50 m × 50 m grids. In 2006 and 2014-2015, we used acoustic surveys to survey the occurrence of Z. arvalis in each grid. We obtained satellite images of the study area for 2006 and 2014, and we assigned the land-cover type of each grid to one of the following six types: woodland, brushland, cropland, bareland, manmade structures and water body. We examined whether Z. arvalis preferred a certain land-cover type by comparing the proportion of cover types available and the proportion of cover types used by the frogs. Furthermore, we used occurrence records for 2006 and 2014-2015 and applied the Maximum Entropy Model to predict suitable habitat for the respective years. We mapped the loss of suitable habitat and used six indices to quantify habitat fragmentation within the 8 years. We also tested the prediction that the occupancy rate of Z. arvalis in different-sized habitat patches was a function of patch size. Zhangixalus arvalis exhibited a strong preference for woodland, but avoided cropland and manmade structures. From 2006 to 2014-2015, the suitable habitat decreased 4.1%, and all six indices showed an increase in habitat fragmentation. The occupancy rate of different-sized woodland patches was positively correlated with patch size. Mapping suitable habitat and identifying the potential gaps in functional habitat connectivity can be used to guide effective measures for conserving Z. arvalis.

Quantifying the Landscape’s Ecological Benefits—An Analysis of the Effect of Land Cover Change on Ecosystem Services

The increasing pressure from land cover change exacerbates the negative effect on ecosystems and ecosystem services (ES). One approach to inform holistic and sustainable management is to quantify the ES provided by the landscape. Using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, this study quantified the sediment retention capacity and water yield potential of different land cover in the Santee River Basin Network in South Carolina, USA. Results showed that vegetated areas provided the highest sediment retention capacity and lowest water yield potential. Also, the simulations demonstrated that keeping the offseason crop areas vegetated by planting cover crops improves the monthly ES provision of the landscape. Retaining the soil within the land area prevents possible contamination and siltation of rivers and streams. On the other hand, low water yield potential translates to low occurrence of surface runoff, which indicates better soil erosion control, regulated soil nutrient absorption and gradual infiltration. The results of this study can be used for landscape sustainability management to assess the possible tradeoffs between ecological conservation and economic development. Furthermore, the generated map of ES can be used to pinpoint the areas where ES are best provided within the landscape.

Evaluation of spatial and temporal water and soil quality in the Buffalo and Brays Bayou watersheds of Houston, Texas

The Buffalo and Brays Bayous are two of the primary drainage channels in the city of Houston. Both the Buffalo and Brays Bayou Watersheds (BBW, BrBW) are impacted by frequent flooding, rapid urbanization and intense land cover changes. The goal of this research is to assess and compare the soil and water quality and land cover changes in the BBW and BrBW. The specific objectives of the study are 1) to monitor and assess the nutrient and metal concentrations in the water and soil samples along the Buffalo and Brays Bayou, 2) to map the long-term land cover changes within these urban watersheds, and 3) to assess the effect of land cover changes on the bayou discharge, water and soil quality of the watersheds. Water and soil samples from several locations along the Brays and Buffalo Bayous were collected during multiple seasons and processed for chemical analysis. Our water sample analysis revealed that the Cu, As and Pb concentrations were higher in the fall compared to the summer and exceeded the critical limit in both the bayous. The soil analysis indicated that the Zn and Pb concentrations were higher in the fall over summer season and exceeded the background concentrations in both BBW and BrBW. The remote sensing analysis revealed that there was a 145% and 140% increase in impervious surface and 34.8% and 34.5% decrease in the vegetative surface in the BBW and BrBW, respectively, due to urbanization during 1984–2019. The contamination of soil and water in BrBW is substantially higher than the BBW. The results of this study provide insights for adoption of best sustainable management practices in urban watersheds.

Anthropogenic and Climate Effects on a Free Dam Tropical River: Measuring the Contributions on Flow Regime

The demand for freshwater resources and climate change pose a simultaneous threat to rivers. Those impacts are often analyzed separately, and some human impacts are widely evaluated in river dynamics—especially in downstream areas rather than the consequences of land cover changes in headwater reaches. The distinction between anthropogenic and climate on the components of the flow regime is proposed here for an upstream free dam reach whose watershed is responsible for the water supply in Rio de Janeiro. Indicators of hydrologic alteration (IHA) and the range of variability approach (RVA) combined with statistical analyses of anthropogenic and climate parameters indicated that (1) four river flow components (magnitude, frequency, duration, and rate of change) were greatly altered from the previous period (1947 to 1967) and the actual (1994 to 2014); (2) shifts in the sea surface temperature of the Atlantic correlated with flow magnitude; (3) the cattle activity effects on the flow regime of the studied area decreased 42.6% of superficial discharge; global climate change led to a 10.8% reduction in the same river component. This research indicated that climate change will impact the intensification of human actions on rivers in the southeast Brazilian headwaters.

Effects of Land Cover Changes on Net Primary Productivity in the Terrestrial Ecosystems of China from 2001 to 2012

The 2001–2012 MODIS MCD12Q1 land cover data and MOD17A3 NPP data were used to calculate changes in land cover in China and annual changes in net primary productivity (NPP) during a 12-year period and to quantitatively analyze the effects of land cover change on the NPP of China’s terrestrial ecosystems. The results revealed that during the study period, no changes in land cover type occurred in 7447.31 thousand km2 of China, while the area of vegetation cover increased by 160.97 thousand km2 in the rest of the country. Forest cover increased to 20.91%, which was mainly due to the conversion of large areas of savanna (345.19 thousand km2) and cropland (178.96 thousand km2) to forest. During the 12-year study period, the annual mean NPP of China was 2.70 PgC and increased by 0.25 PgC, from 2.50 to 2.75 PgC. Of this change, 0.21 PgC occurred in areas where there was no land cover change, while 0.04 PgC occurred in areas where there was land cover change. The contributions of forest and cropland to NPP exhibited increasing trends, while the contributions of shrubland and grassland to NPP decreased. Among these land cover types, the contributions of forest and cropland to the national NPP were the greatest, accounting for 40.97% and 27.95%, respectively, of the annual total NPP. There was no significant correlation between changes in forest area and changes in total annual NPP (R2 < 0.1), while the correlation coefficient for changes in cropland area and total annual NPP was 0.48. Additionally, the area of cropland converted to other land cover types was negatively correlated with the changes in NPP, and the loss of cropland caused a reduction in the national NPP.

Study of habitat quality assessment using geospatial techniques in Keoladeo National Park, India.

Wetlands are one of the most productive ecosystems on the Earth. They are generally considered a transitional state between terrestrial-aquatic habitats and provide numerous vital ecosystem services to mankind. Wetlands are under a tremendous pressure due to growing human interference, urbanization, conventional agriculture, industrial expansions, and overexploitation of ecological services. The Keoladeo National Park (KNP) is a manmade wetland, world heritage site and a designated Ramsar site in India, widely known for its avian biodiversity. Due to insufficient amount of water supply and widespread invasion of Prosopis juliflora, notable spatio-temporal changes are observed in the land cover affecting habitat quality of the park. The present study is designed to highlight the importance of very high-resolution satellite data for characterization of the wetland ecosystem. It assesses the spatio-temporal dynamics of land use/land cover (LULC) and habitat quality, a model built in the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) tool, is utilized to analyze the effect of land cover changes and increase in P. juliflora on habitat quality in the park. The study concludes that drastic changes in LULC and rampant spread of P. juliflora have deteriorated the quality of habitat for bird species. Furthermore, it highlights importance of geospatial tools in mapping, monitoring, and managing wetland ecosystems.

Estimating possible bumblebee range shifts in response to climate and land cover changes

Wild bee decline has been reported worldwide. Some bumblebee species (Bombus spp.) have declined in Europe and North America, and their ranges have shrunk due to climate and land cover changes. In countries with limited historical and current occurrence data, it is often difficult to investigate bumblebee range shifts. Here we estimated the past/present distributions of six major bumblebee species in Japan with species distribution modeling using current occurrence data and past/present climate and land cover data. The differences identified between estimated past and present distributions indicate possible range shifts. The estimated ranges of B. diversus, B. hypocrita, B. ignitus, B. honshuensis, and B. beaticola shrank over the past 26 years, but that of B. ardens expanded. The lower altitudinal limits of the estimated ranges became higher as temperature increased. When focusing on the effects of land cover change, the estimated range of B. diversus slightly shrank due to an increase in forest area. Such increase in forest area may result from the abandonment of agricultural lands and the extension of the rotation time of planted coniferous forests and secondary forests. Managing old planted coniferous forests and secondary forests will be key to bumblebee conservation for adaptation to climate change.

Spatial Assessment of the Effects of Land Cover Change on Soil Erosion in Hungary from 1990 to 2018

As soil erosion is still a global threat to soil resources, the estimation of soil loss, particularly at a spatiotemporal setting, is still an existing challenge. The primary aim of our study is the assessment of changes in soil erosion potential in Hungary from 1990 to 2018, induced by the changes in land use and land cover based on CORINE Land Cover data. The modeling scheme included the application and cross-valuation of two internationally applied methods, the Universal Soil Loss Equation (USLE) and the Pan-European Soil Erosion Risk Assessment (PESERA) models. Results indicate that the changes in land cover resulted in a general reduction in predicted erosion rates, by up to 0.28 t/ha/year on average. Analysis has also revealed that the combined application of the two models has reduced the occurrence of extreme predictions, thus, increasing the robustness of the method. Random Forest regression analysis has revealed that the differences between the two models are mainly driven by their sensitivity to slope and land cover, followed by soil parameters. The resulting spatial predictions can be readily applied for qualitative spatial analysis. However, the question of extreme predictions still indicates that quantitative use of the output results should only be carried out with sufficient care.

Effects of Land Cover Changes on Sediment and Nutrient Balance in the Catchment with Cascade-Dammed Waters

It is commonly believed that changes in the use of the catchment area have a direct impact on the quality of the water environment. Rivers with dams and reservoirs are characterized by a disturbed outflow of sediments and nutrients from the catchment area. The research was based on indicating the variation in time and space of loads of selected parameters of the water quality of the Brda River (Northern Poland) against the land cover changes based on the CORINE Land Cover (CLC) data for the 1990–2018 period. In the lower part of the Brda catchment area, there are three hydropower dams with reservoirs in the form of a cascade, whose work clearly affects the hydrological regime of the river. The analysis of the dependence of the dynamics of water quality changes on the usage of CLC was based on indicators such as sediments (suspended sediment load) and nutrients (total phosphorus load and total nitrogen load). The use of hydrological data on the Brda discharge above and below the reservoirs made it possible to calculate sediment and nutrient trapping efficiency. Linking the CLC data with the indices responsible for the mechanical denudation of the catchment area made it possible to show the strength of changes taking place in the catchment area. The results of the research do not indicate any direct correlation between land cover changes and the dynamics of the denudation process and matter transport in the Brda catchment area. As our research shows, the strong influence on the hydrological regime of the catchment points out the necessity to search for still other research methods supporting the decision-making cycle in the field of water management in the face of climate change.

Assessment of the impact of land-cover change on water quality: case study of the Chiba watershed, Nabeul, Tunisia

Water scarcity and water quality degradation are important problems that can affect human well-being. Population growth, unplanned urbanization, land-cover change, and the intensification of agricultural and industrial activities are the main reasons for water resource issues. The main aim of this work was to evaluate the effect of land-cover change on groundwater quality in the Chiba watershed, Nabeul, Tunisia. A remote-sensing technique was used to identify the principal transitions in land cover between 1998 and 2018. Additionally, four water quality indicators (electrical conductivity, chloride concentration, nitrate concentration, and sodium absorption ratio) were utilized to investigate variations in water quality in the study area. It was found that most of the watershed was covered with agricultural land in 1998 (87.5%) and 2018 (88.6%). Based on a comparison of these two periods, various types of land-cover transitions were observed. Moreover, the water quality indicators revealed that the salinity hazard and nitrate contamination in the watershed were high. The spatial relationship between water contamination level and land-cover transition category indicated that barren land to built-up land transitions had the strongest negative effect on water quality among all of the main land-cover transitions. Demonstrating the impact of land-cover change on water quality should encourage local decision makers and water managers to implement strategies for sustainable urban planning and periurban agriculture.

A methodology to assess the future connectivity of protected areas by combining climatic representativeness and land-cover change simulations: the case of the Guadarrama National Park (Madrid, Spain)

Protected areas are fundamental in conservation, but their intactness is increasingly threatened by the effects of climate and land-cover changes. Here, a methodological procedure is proposed able to determine the representative climatic conditions of a protected area in central Spain (Guadarrama National Park) pinpointing the natural areas that will host future analogous conditions, but also assessing the effects of land-cover changes on the connectivity of these areas. Future conditions provided by two 2050 IPCC climatic change scenarios and land-cover change simulations were jointly used for this purpose. According to the results obtained, climate change will produce notable effects, displacing its representative climatic conditions as well as modifying the land cover in the neighboring localities. Three areas appear as fundamental for the future maintenance of this reserve: two within the Iberian Central System (Gredos Mountains and Ayllón Mountains) and one in the Iberian System (Urbión Mountains). The proposed approach can be implemented in any protected area to examine its capacity to represent in the future the environmental conditions for which it was created.

Land use intensification rather than land cover change affects regulating services in the mountainous Adige river basin (Italy)

Land Cover (LC) and Land Use (LU) changes are usually considered as one change, limiting the understanding of their individual effects on Ecosystem Services (ESs). The aim of this study is to investigate the different effects of LC change and LU intensification on four regulating ESs (carbon storage, water regulation and supply, nitrogen retention) using the InVEST model in the mountainous Adige river basin (Northern Italy) during 1960–2012. The role of establishing protected areas (PAs) in the four regulating ESs was also investigated. The results showed that pasture abandonment and agricultural intensification were the most important LC and LU changes, respectively. The total value of crops’ production raised four times, mainly due to agricultural intensification (increase of fertilization rates), while nitrogen losses increased threefold during 1960–2012. Significant changes on carbon storage and water balance components were not observed due to LC and LU changes at basin scale. The results highlighted the tradeoff between crop production and nitrogen losses that affect water quality regulation. PAs establishment was not enough to mitigate nitrogen losses. The results of the study highlighted that LC change and LU intensification should be considered separately to better understand the consequences of anthropogenic impact on regulating ESs.

Cropland expansion outweighs the monetary effect of declining natural vegetation on ecosystem services in sub-Saharan Africa

Changes in land cover and land degradation alter natural ecosystems, thereby affecting the services these ecosystems provide. However, there have been few attempts to estimate the effects of land cover change and land degradation on ecosystem services at large spatial scales and under the strong influence of human activities. Here, we used the European Space Agency Climate Change Initiative land cover maps (1992–2015) and the value transfer valuation method to estimate the changes in ecosystem services value (ESV) in response to land cover change in sub-Saharan Africa (SSA). Moreover, we estimated the loss of ESV due to land degradation by using the long-term (1992–2015) trend in the annual normalized difference vegetation index as a proxy for long-term biomass productivity decline. Our results revealed that, between 1992 and 2015, cropland increased by about 20 million ha, largely at the expense of forest and shrubland. The total estimated ESV of SSA was about US$9 trillion year−1, of which 55% was derived from cropland and deciduous forest, with comparable contributions. Land cover change resulted in a net increase in the total ESV by US$125 billion year−1 (1992–2015), albeit with an ESV loss of US$60 billion year−1 from the conversion of evergreen forest and shrubland. Overall, cropland expansion accounted for about 60% of the increase in the total ESV (US$125 billion year−1), thereby outweighing the decrease in ESV due to the decline in natural vegetation. Land degradation hotspots covered about 5% of SSA, resulting in a total ESV loss of about US$56 billion year−1, of which nearly 65% was due to the degradation of forests and croplands. Changes in ESV varied across sub-regions, climate zones, and countries, depending on the dominant land cover change and the extent of land degradation. Our results provide useful insights for making informed decisions towards sustainable use and management of ecosystems.

Effect of Land Cover Change on Discharge in Pangkajene Watershed

Land cover changes that occur impact on the hydrological conditions in a watershed. The hydrological condition referred to as the output quantity of the watershed is discharge which describes the quantity of water. This study aims to determine the effect of land cover change on streamflow in the Pangkajene Watershed. The results showed that there was a decrease in average peak discharge in January of 213.73 m3/s to 95.79 m3/s in the same month in 2017. Land cover changes that occurred were mixed dryland farming of bushes into paddy fields, shrubs, and settlements while forests was experienced a slight change to open land by 0.69 ha. The increase in the area of paddy fields and shrubs as large as it causes the average discharge to decrease. A decrease in the average monthly discharge in the Pangkajene watershed due to rainfall on its way into the rice irrigation water experienced process begin from, is accommodated, evaporates, so that the flow up to the river becomes small. In addition, rainfall in 2009 which is the input of the Pangkajene watershed is higher than in 2017.

Sustainable Development in Nasser Lake using the Integration of Multi-Temporal Remote Sensing Imagery and GIS

Water is considered one of the most essential elements for life on the earth. Egypt is one of the countries in the world suffering from the water shortage because of the global temperatures increase, decreased precipitation levels due to the climate changes. Furthermore, the misuse of water resources and inefficient irrigation techniques are additional factors worsen the water security in Egypt. Nasser Lake was created as a result of the construction of the Aswan High Dam (AHD) in 1960s to control flooding, store the increased water and produce hydroelectricity.The objective of this research was to monitor and detect the changes in Nasser Lake using integrated techniques of satellite images and GIS. Two Landsat images acquired in 2000 and 2019 are used to investigate land cover changes in the lake and its surroundings. The findings indicated that Nasser’s Lake total area decreased from 5887.7 km2 in 2000 to about 5364.4 km2 in 2019. Five classes are obtained from classifying satellite images, namely: deep, shallow water, bare soil from type 1 and 2 in addition to quarries. Post classification change detection showed that deep water was 5485.4 km2 in 2000 and decreased to be 4490.9 km2 in 2019. The shallow water increased from 402.4 km2 in 2000 to 573.5 km2 in 2019. Markov chains is applied to predict and simulate the future land cover changes from 2019 to 2050 to safeguard against the adverse effects and negative consequences of land cover changes and consequently achieve goals of sustainable development

ANALISIS PENGARUH PERUBAHAN TUTUPAN LAHAN TERHADAP HIDROLISIS DAS PAMUKKULU SULAWESI SELATAN

The Pamukkulu watershed is one of the Jeneberang-Kelara Sub-watersheds, which is one of the 108 Priority Watersheds in Indonesia determined based on the 2017 Ministry of Environment and Forestry Performance Report which is prioritized as a location for Forest and Land Rehabilitation activities. The purpose of this study was to analyze changes in land cover in the Pamukkulu watershed in 2008 and 2017, the effect of land cover changes in the Pamukkulu watershed on fluctuations in major river flows and analyze the health level of the Pamukkulu watershed based on analysis of major river discharge and changes in land cover. The study was conducted in February to April 2018. Data collection was carried out by taking secondary data in the form of land cover data in 2008 and 2017, climate data and Pamukkulu River discharge data. The results showed that based on the results of the analysis of the Land Cover Index (IPL), the condition of Pamukkulu watershed land cover in 2008 was at 19.38% and 16.96% in 2017 so that it was categorized as bad. The results of the hydrological analysis (river water discharge) on the River Regime Coefficient in 2008 were 125 and in 2017 amounted to 119.6 so that the KRS is also categorized as bad. While the results of the analysis of the Variant Coefficient (CV) in 2008 amounted to 144.90% and in 2017 amounted to 87.5% then the CV was categorized as poor. Based on the analysis of the value of the Land Cover Index, River Regime Coefficient and River Regime Coefficient in the Pamukkulu Watershed in 2008 and 2017 which are in the poor category, the performance of the Pamukkulu Watershed is in the poor category.

Effect of Land Cover Change on Atlantic Forest Fragmentation in Rio Largo, Al, Brazil

This study's objective was to analyze the effect of land cover change, between 1965 and 2018, using statistical metrics and geoprocessing tools. And consequently, to provide information of area (ha) and spatial fragmentation of the Atlantic Forest in the municipality of Rio Largo/AL, Brazil. The samples were collected and transferred by CECA, CADEH, and INCRA, between November 2019 and April 2020. The basic materials used in this work were multi-temporal aerial images in digital format, derived from the 1965 aerophotogrametric survey on the scale 1:25000, belonging to the collection of the Engineering and Agrarian Sciences Campus - UFAL, and images of Landsat satellites (5 and 8) processed and made available by the Mapbiomas Project. The statistic landscape metrics were calculated using Landscape ecology Statistics (LECOs), a QGIS plugin. The analysis of forest fragmentation areas over the 53 years showed a reduction between 32.17% (1965) and 12.04% (2018) concerning the total extension of the municipality. In 1965, the average area obtained from 49 fragments was 201.13 ha. The values show a higher distance of forest fragments between 1965 and 1989, and disappearance by 2018.The Pearson correlation coefficient for 1965 and 2018 presented the value of r = -0.525, indicating a moderate and negative correlation between the mean values of areas (ha) of forest fragments and the number of forest fragments. The worst-case scenario for the maintenance of native forests occurred in 1989, where the reduction of continuous forest areas had 10.87 ha for forest area average, being spaced in 327 fragments. In the period 1986 and 1996, there was a decrease in fragmentation, reaching 200 fragments. In 1996 and 1997, there was an imbalance in forest maintenance, again increasing the number of fragments to 250 areas, and being explained by the loosening of surveillance in previous years, followed by deforestation.

Impact of Forest Disturbance on InSAR Surface Displacement Time Series

As interferometric synthetic aperture radar (InSAR) data improve in their global coverage and temporal sampling, studies of ground deformation using InSAR are becoming feasible even in heavily vegetated regions such as the American Pacific Northwest (PNW) and Sumatra. However, ongoing forest disturbance due to logging, wildfires, or disease can introduce time-variable signals which could be misinterpreted as ground displacements. This study constrains the error introduced into InSAR time series in the presence of time-variable forest disturbance using synthetic data. For satellite platforms with randomly distributed orbital positions in time (e.g., Sentinel-1), mid-time series forest disturbance results in random error on the order of 0.2 and 10 cm/year for 1-year secular and time-variable velocities, respectively. If the orbital positions are not randomly distributed in time (e.g., ALOS-1), a biased error on the order of 10 cm/year is introduced to the inferred secular velocity. A time series using real ALOS-1 data near Eugene, OR, USA, shows agreement with the bias estimated by synthetic models. Mitigation of time-variable land cover change effects can be achieved if their timing is known, either through independent observations of surface properties (e.g., Landsat/Sentinel-2) or through the use of more computationally expensive, nonlinear inversions with additional terms for the timing of height changes. Inclusion of these additional terms reduces the potential for misinterpretation of InSAR signals associated with land surface change as ground deformation.

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