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The basin of the small river studied here (the Vezelka River, Belgorod Oblast of European Russia) is located within an urban area (22% of the basin). This circumstance determines its specificity as an object of synergetic anthropogenic impact. The purpose of the work was to develop and test approaches to the integral assessment of the hydroecological situation both in the watershed and riparian zones based on hydrological, hydrochemical, and hydrobiological data and estimates of soil erosion, river water quality, and the pollution of river bottom sediments. The selection of the Vezelka River and its watershed for the study was due to the presence there of two water intakes for a town with a population of 2439 people per sq. km, repeated bottom deepening in the riverbed, and the fact that there is a single regional small-river hydrological station (although there are 567 rivers < 25 km long in Belgorod Oblast). Analysis for 1951–2021 showed a steady decline in water discharge since 1991; thus, over the past three decades, the discharge has decreased by 2.4 times. The reduction in the length of the river network of the study region by 38% over the past 250 years and the assignment of water (at 10 gauging stations) to 3–4 quality classes (extremely and heavily polluted) indicated the exhaustion of the possibilities for the self-purification of the river water. These estimates for large and medium rivers were clearly confirmed by the investigation of the water in the small river studied. In the summer low-water periods, the maximum allowable concentrations in fishery water bodies were exceeded by 2–10 times in terms of Cu, Fe, ammonium, oil, and biochemical oxygen demand. The reconstruction of the floodplain–channel subsystem of river–valley landscapes was substantiated as the final stage of the concept of basin nature management, replacing the continuous deepening of the channel without proper erosion control measures in the watershed area and the organization of buffer zones along the river banks.

Social distance memaksa semua sektor untuk berinovasi, salah satunya pada dunia pendidikan. Dimana pemerintah meminta sekolah untuk melaksanakan pembelajaran jarak jauh dengan menggunakan pembelajaran daring. Kegiatan pembelajaran daring jauh lebih sulit dilakukan daripada pembelajaran tatap muka dikarenakan harus memanfaatkan beberapa teknologi dalam penerapannya serta mampu menggunakan model, strategi, media, bahan ajar dan penilaian yang tepat. Keadaan ini menjadi tantang tersendiri terlebih pada guru. Maka perlu kesiapan yang optimal dalam pelaksanaan pembelajaran daring terutama di sekolah dasar yang berada di lingkungan DAS (Daerah Aliran Sungai). Penelitian ini menggunakan pendekatan kualitatif deskriptif yang bertujuan untuk mendeskripsikan dan menggambarkan kesiapan guru dalam pembelajaran daring. Subjek penelitian yang dilakukan ke 24 orang guru dari tiga sekolah dengan menggunakan teknik random sampling. Hasil penelitian yang didapatkan dari pelaksanaan pembelajaran dari di ketiga sekolah ini ialah masih kurang optimal persiapan yang dilakukan oleh guru, dikarenakan beberapa faktor, yakni lingkungan masyarakat dan orang tua/wali siswanya yang kurang mendukung, sarana dan prasarana di sekolah yang masih kurang dan SDM yang ada di sekolah yang ada beberapa belum mampu melaksanakan kegiatan pembelajaran daring dengan baik. Sehingga nanti diharapkan ada perbaikan dan solusi pemecahan masalah dari kurang optimalnya persiapan pelaksanaan pembelajaran daring ini di beberapa sekolah.

This study aims to assess Flood susceptibility and flood hazard levels and obtain the distribution of hazard levels and flood hazards in the Woyla watershed, Aceh Province. This research design generally uses a descriptive survey method and divide into several stages, such as data collection, data processing, data presentation, and delivery of research results. Each determinant of flood-prone areas includes a land slope, altitude, soil texture, drainage, land cover, and rainfall, analyzed spatially utilizing a map. Furthermore, based on the map, the regions are described based on the values that have been divided into classes. The results showed that the level of flood vulnerability in the Woyla watershed was divided into five classes, namely; the non-vulnerable class with an area of 14.88 Ha / 0.01%, low prone with an area of 90,731.62 Ha / 35.45%, medium with an area of 57,120.35 Ha / 22.32%, high with an area of 44,918.15 Ha / 17.55%, and very high with an area of 63,151.72 Ha / 24.67%. Also obtained a map of the distribution of flood hazard areas, the Woyla watershed area is divided into five classes, namely; the very light class with an area of 179,146.15 Ha / 70.00%, mild with an area of 32,868.84 Ha / 12.84%, moderate with an area of 20,129.93 Ha / 7.87%, danger with an area of 6.007. 29 Ha / 2, 35%, and very dangerous with an area of 17,784.51 Ha / 6.95%. The level of flood vulnerability in the Woyla watershed is dominant in West Aceh Regency, which is in the very high and high category classes with a total area of 56,876.65 Ha and 23,527.40 Ha. Meanwhile, the level of flood hazard in the Woyla watershed is also more dominant in West Aceh Regency than falls into the most dangerous and dangerous class category with a total area of 17,784.51 Ha and 6,007.29 Ha. With the largest part in the very light class at the flood hazard level of 179,146.15 ha.

Playa wetlands are widely distributed across the High Plains of the central United States, providing a range of ecosystem services, such as groundwater recharge, surface water storage, and wetland habitat. Although playas are essential resources, few studies have examined the variability and controls on playa water storage. The purpose of this project is to determine how playa and watershed morphology, watershed land cover, and precipitation patterns affect timing and duration of water storage in playas. This project focuses on 92 playas distributed throughout a 10-county region in western Kansas. Playa and watershed morphology were calculated in a GIS environment and classified into quartiles based on playa and watershed surface area. Watershed tilled index (i.e., percent cropland versus grassland) was determined using 2016, 2017, 2018, and 2019 Cropland Data Layers available from the National Agricultural Statistics Service and classified as either cropland (more than 75% cropland), grassland (more than 75% grassland), or mixed. Monthly precipitation data for 2016–2019 were compiled from the Oakley 22S High Plains Regional Climate Center weather station. Playa water status for 2016–2019 was classified monthly as either standing water or dry (i.e., no visible standing water) by visually examining four-band satellite imagery with 3.7 m resolution available from Planet Explorer (www.planet.com). Playa water status is influenced by a combination of factors, including playa and watershed morphology, watershed land cover, and precipitation patterns. Larger playas have larger watersheds and standing water more frequently and for longer periods than smaller playas. Playas in cropland watersheds store water more frequently and for longer periods than playas in grassland watersheds, though differences are not statistically significant. Standing water within playas is positively correlated with monthly precipitation and reflects a short-term response to precipitation patterns, regardless of playa size or watershed land cover. The strongest controls on playa water status are playa area, monthly precipitation, and watershed area. Playas are critical resources for the High Plains, providing a range of ecosystem services that are dependent upon the playa’s ability to store water. Playa functions are under continued threat from cropland expansion, climate change, and playa and watershed modifications. To sustain playa functions in Kansas, efforts should focus on conserving larger grassland playas and reducing sediment inputs to playas in cropland watersheds.

Anggomate River has ecological and economic value for the local community. Massive community activities in utilizing land in the Anggomate watershed area for plantation, inhabitation, and sand mining lands can cause the tree vegetation decline, even flood often occurs in Andowia region annually. The research method used was a quantitative method. Sampling was performed through a plot-transect method. The plots were placed on the downstream (Labungga Village river area), middle (Laronaga Village river area), and upstream (Andowia Village river area) regions. The study results showed that there are 35 tree species with the individual number of 64. The highest importance value index was obtained from Ficus benjamina L. at 29.38%, Anthocephalus cadamba (Roxb.) Miq) at 25.64%, and Lansium domesticum Corr. at 16.81%. The dominance index of the tree species in the Anggomate river area was 0.971, which indicates that one of the tree species dominated this area, namely, Anthocephalus cadamba (Roxb.) Miq) (Roxb.) Miq). The diversity index in the Anggomate watershed area includes in high category (H’= 3.402 atau H’ > 3). The distribution index includes in the evenly distribution category due to obtaining closely approaching the value of 1 (E= 0.818).

Land degradation resulting from soil erosion is a major problem in rain-fed agricultural areas in India. This study analyses the key determinants of farmers’ decisions to adopt on-farm soil and water conservation (SWC) measures in the rain-fed watershed areas of Siddipet district in Telangana. Here, SWC measures have been undertaken by the government and NGOs at the sub-watershed/community level and by individual farmers at the farm level. The study is based on a primary survey of over 400 farmers conducted in January–March 2018. In addition to estimating the influence of biophysical and market access variables on farmers’ decisions to undertake SWC practices, the study includes a logistic model that found a complementarity between community and individual plot-level interventions to improve soil health. The findings also highlight the influence of conservation measures practised in the neighbourhood on farmers’ decisions to implement SWC measures.

Water is an important resource of the earth’s surface and it is integral for all on this planet. The availability or the scarcity of water depends on the watershed characterizes that consider the basic, linear, and shape parameters of any waterbody. The objective of the study was to delineate 14 morphometric parameters in the Barind region (Dinajpur district, Bangladesh) for sustainable hydrological modeling. An ASTER-DEM of 30-meter resolution data, geographical information system (GIS), and Remote sensing technique were used for extracting drainage components of interest region. The whole study region was covered by the flow of the Purnovoba river, Jamuna river, Atrai river (part-1 and part-2). Research results found that the Purnovoba river had a high bifurcation ratio (0.9982) that defined hydrologically more disturbed than the other three watershed areas and it had a high stream frequency (0.8332) that denoted rocky having low infiltration capacity. Jamuna river had a low drainage density (0.7322) that defined more vegetation having higher permeability. Besides, the Jamuna river had the lowest no. of stream order that was insignificant in the steady runoff process and less prone to cause a flash flood. The research predicted that the availability of groundwater might decrease to Jamuna river in the future as it had the lowest basin area (217.42 sqr. km ) and perimeter (114.90 km) and the basin surface slope would become gentle to Atrai river part-1 for the lowest length of overland flow (0.6072). Purnovoba river experienced the lowest form factor (0.2351) which indicated the most possibility for erosion. The elongated ratio of all basins was greater than 0.5 which considered all the shapes were more elongated. These findings will help for further modeling of an integrated watershed for sustainable hydrological models in the Barind region.

The Benanain Watershed is located in East Nusa Tenggara with an area of 3,181 km2 and is divided into 29 sub-watersheds. The East Nusa Tenggara itself is an eastern region of Indonesia with a unique climate condition called semi-arid. The high rainfall intensity occurring in short duration results in large surface runoff and erosion. Floods and erosion in semi-arid areas due to sensitive soils to drought and heavy rainfall extremely. This paper presents the application of the Soil Conservation Services-Curve Number (SCS-CN) real-flood flows through a digital map of soil type, land use, topography, and the heterogeneity of physical condition, especially for ungauged watersheds. The method used is an approach empirical to estimate runoff from the relationship between rainfall, land use, and soil hydrology groups. This watershed has a large area that must analyze every sub-watershed. The land-use of the Benanain watershed is secondary dryland forest by 44.26% and the hydrological soil group on the B group classification with medium to high absorption potential by 46.502% from the total area. The curve number value of the Benanain Watershed ranges from 56.54 to 73.90, where the mean CN value of 65.32. The rainfall (mm) for the 29 sub-watersheds in the Benanain Watershed has decreased by about 74.65% when being surface runoff or only 25.35% of water becomes surface runoff. The relationship between rainfall depth and CN is classified as standard response and trend line (flat slope) equilibrium occurs when rainfall depth value of 56.71 mm and CN is close to 66.30. The high variability of intense rainfall between the rainy season and the dry season had a significant influence on the curve number value in a large watershed area. Further analysis will be more accurate if it is supported by long rainfall data and observation runoff data as a control. Doi: 10.28991/cej-2021-03091711 Full Text: PDF

The suspension flow from the upper part of a volcano watershed, which has a very thick soil condition, is sensitive to landuse form. Agroforestry is the dominant landuse form in the volcanic landscape of Indonesia. There is a lack of detailed studies about suspension flow in the upper watershed where agroforestry is the land cover. This research, performed in agroforestry area, covered the correspondence between flow discharge and suspension flow discharge, the time lag of initial rain events and the formation of suspension flow; and the characteristics of the grain size of the suspensions during the flow. The suspension flow was measured at the outlet of a gully in key watershed areas, which yielded a total of 436 suspension data. The measurement analysis was conducted at every rain event in the field and in the laboratory. The crop characteristics in the rain catchment area were recorded in details during the field survey. The characteristics of the channels converging toward the gully system were observed during the field survey. There were three relationship patterns between the peak flow discharge and the peak suspension discharge, namely (1) the peak flow discharge corresponded to the peak suspension discharge, (2) the peak flow discharge preceded the peak suspension discharge, (3) the peak flow discharge occurred after the peak suspension discharge. The average time interval between the rain events and the occurrence of suspension flow was 17.7 minutes. The peak suspension content varied from 0.0016 g/L up to 4.71 g/L with an average of 1.03 g/L. The grain size of the suspension was dominated by 71-76% of clay fraction with an average of 73% at the rising phase and 68-71% of clay fraction with an average of 69% at the falling stage

Paddy is a staple food for most Indonesian people. A number of efforts were made to maintain the availability of paddy in the country. One of these efforts is to determine the beginning of the paddy planting season, especially lowland paddy in order to get maximum results and minimize crop failure. This study aims to determine the beginning of the growing season in the Limboto Bone Bolango watershed area. The beginning of the rainy season is the best time to be the beginning of the paddy planting season which requires sufficient irrigation in the vegetative phase. The data used in this study is rainfall time series data which is processed from TRMM 3B43 data: Monthly Precipitation Estimates (TRMM/3B43V7) and ERA5-Land monthly averaged - ECMWF climate reanalysis (ECMWF/ERA5_LAND/MONTHLY). Based on the time series data, the beginning of the rainy season is in February (DOY > 60) and October (DOY > 273). Based on this, it is expected that farmers in the Limboto Bone Bolango watershed can start the planting season in February and October.

This study aimed to assess land degradation sensitivity of an area contributing to desertification risk in Lam Ta Kong Watershed using Environmental Sensitivity Area Index (ESAI). Five risk factors comprised climatic, soil, geographical, land utilization and vegetation, and water resources factors together with fifteen sub-factors were used to analyze the sensitivity to land degradation. The spatial analysis was calculated using Geographic Information System (GIS) and Remote Sensing (RS) techniques. The key factors influencing land degradation risks in the watershed area were analyzed using the triangular fuzzy numbers (TFNs) method. The results showed that approximately 33% of Lam Ta Kong watershed was affected by a high desertification risk excluded the water bodies and around 24.64% of the area suffered from a moderate risk. This research pointed out that key factors causing land degradation and desertification in the watershed area were related to the soil factors, followed by climatic, geographical factors, water resources, and land utilization and vegetation, respectively. The results of this study can be used as a database for planning and implementing area-based mitigations and measures as well as for land use planning in the watershed area.

This research integrated easy-to-handle remote sensing data and geoinformatics techniques for erosion mapping and groundwater management in the River Amba watershed, central Nigeria. It is aimed at: (a) the determination of the erosion-prone areas and (b) the estimation of the groundwater potential contamination risk under current and future anthropogenic activities. Rainfall intensity was evaluated from monthly rainfall data (2001 - 2011) from the station located within the River Amba Watershed. Digital Elevation Model (DEM) for the terrain was created using the 3D Analyst tool (Surfer 14) and was used to determine the flow direction and lineament features in each raster cells. Remote sensing data (aerial photographs and LANDSAT imagery) were used to develop a land-use map, while geological mapping was used to determine the local geology of the watershed area. The contributions of the various factors to the erosion hazardous areas are: elevation 31.49 %, land use 21 %, slope 14 %, geology 12.52 %, rainfall intensity 10.5 % and flow accumulation 10.5 %. The combined influences of these factors to erosion susceptibility as either: very high, high, moderate, low, and very low with the south-western part characterized as high while other parts of the study area moderate to very low erosion vulnerability. The groundwater level is shallow (4.0 –28.5 m) and discharges through the Amba river and many springs. These springs along with boreholes and wells supply drinking water to Lafia and the environs.

The population in urban areas continues to increase while the land owned is limited which results in slum settlements in urban areas. Slum settlements in Medan City often appear in areas where buildings should not be allowed, such as in watersheds. Deli River as a large river that divides Medan City, there are still many slum settlements in the watershed. Management of slum settlements based on sustainable development is needed to provide a long-term impact, especially for the preservation and restoration of the function of the Deli River. This study aims to analyze the management of slum settlements based on sustainable development indicators in achieving sustainable development, namely ecological sustainability, economic sustainability, socio-cultural sustainability, political sustainability, and defense and security sustainability. The research method used is descriptive qualitative. Sources of research data by collecting primary data through interviews and secondary data through documentation and observation studies. The management of slum settlements based on sustainable development in the Deli watershed is still not optimal in terms of ecological sustainability, economic sustainability, and defense and security sustainability. Meanwhile, socio-cultural sustainability and political sustainability are quite optimal. The government must manage slum settlements based on sustainable development through an approach with the community and provide viable housing alternatives so that people do not live in watershed areas.

Tambakbayan is one of the watersheds in Yogyakarta, Indonesia that is experiencing changes in land use. The research aims to analyze the distribution of intrinsic and specific groundwater vulnerability in the watershed that was influenced by land-use changes from 2006 to 2017. The data used are the RBI maps (containinh topographic and land-use information, 2006 and 2017), SRTM imagery, rainfall recorded at the Kambil, Prumpung, Bronggang, Santan, Gemawang, and Karang Ploso stations (2006-2017), soil map, and aquifer map. Land-use change was analyzed by comparing the RBI maps of 2006 and 2017; while the groundwater vulnerability was assessed with the Susceptibility Index a development of the DRASTIC method. The intrinsic groundwater vulnerability was generated based on physical conditions, including depth to the water table, aquifer media, groundwater recharge, and topography, while the specific groundwater vulnerability was a function of these attributes added with one anthropogenic parameter : land-use. Then, all of these parameters were analyzed with map ovelay. The results showed two levels of intrinsic vulnerability : low (2.18% of the watershed area) and medium (97.8%); and three classes of specific vulnerability : low (0.02%), medium (5.06%), and high (94.92%)in 2006. From 2006 through 2017, the areal percentage of the medium vulnerability increased, while that of the high vulnerability decreased due to the conversion of agricultural land to a reservoir in 2009.

In this paper, we focus on the assessment of land-use and land-cover change detection mapping to the effective planning and management policies of environment, land-use policy and hydrological system in the study area. In this study the soil and water conservation project has been applied during the five years and after five years what changes have been found in the land-use and land-cover classes and vegetation. In this view, this land-use and land-cover mapping is a more important role to decide the policy for watershed planning and management project in the semiarid region. In an emerging countries, fast industrialization and urbanization impose a significant threat to the natural atmosphere. The remote sensing and GIS techniques are crucial roles in the study of land-use and land-cover mapping during the years of 2007, 2014, and 2017. The main objective of this is to prepare the land-use and NDVI maps in the years of 2008, 2014 and 2017; these maps have prepared from satellite data using the supervised classification method. A normalized difference vegetation index map (NDVI) was done by using Landsat 8 and LISS-III satellite data. NDVI values play a major role in monitoring the vegetation and variation in land-use and land-cover classes. In these maps, four types of land are divided into four classes as agriculture, built-up, wasteland, and water body. The results of study show that agriculture land of 18.71% (158.24 Ha), built-up land of 0.62% (5.31 Ha), wasteland of 40.33% (341.02 Ha), and water body land of 17.39% (147 Ha) are increased. Land-use and land-cover maps and NDVI values show that agriculture land of 22.97% (194.29 Ha), 5.46% (14.59 Ha), and 0.08% (0.22 Ha) decreases during the years of 2008, 2014, and 2017. The results directly indicate that the supervised classification method has been the accurate identified feature in the land-use map classes. This classification method has been given the better accuracy (95%) from spatiotemporal satellite data. The accuracy was also tally with ground-truth and Google earth information. These results can be a very useful for the land-use policy, watershed planning, and management with natural resources, animals, and ecological systems.

Due to the intensive human activities and rapid economic development during the past few decades, the anthropogenic sourced nitrogen (N) input into coastal waters has increased dramatically. In this study, the net anthropogenic nitrogen input (NANI), including the deposition of atmospheric N, the application of N fertiliser, the fixation of biological N, and the net N inputs from food and feed, into the Zhanjiang Bay watershed from 1978 to 2018 were estimated using statistical data, and the driving forces were analysed using the Logarithmic Mean Divisia Index (LMDI) factor decomposition approach. The results show that the NANI dramatically increased from 5269 to 20 639 kg N km−2. The cause of this increase was related to high input from N fertilisers and the net food and feed N input (with average contributions of 56.45% and 41.42%, respectively), which was accompanied by rapid economic development in Zhanjiang Bay. The output from the LMDI illustrates that the cause of the changes in the NANI was a shift in the dietary structure instead of an increase in the human population, which suggests that the impact of human population on the increase in the NANI using simple relational analysis may be overestimated. Remarkably, we found that the N from aquatic protein and animal protein comprised a significant proportion of the total N consumption in this coastal city, which differs from previous studies of inland cities. This is likely due to the fact that aquaculture is significantly developed in this coastal city.

In environmental management, land cover change is a crucial aspect. The area of tropical savanna environments is vulnerable to land degradation. This study aimed to rapidly detect land cover changes in a tropical savanna environment based on remote sensing data. Conditional change detection was performed using the Change Vector Analysis (CVA) with input parameters such as the Enhanced Vegetation Index (EVI) and Normalized Difference Soil Index (NDSI). The results showed that during the period 2015 to 2019, changes were detected in the Moyo watershed every year. From 2015 to 2016, the Moyo River Basin was dominated by changes with a change magnitude of less than 0.088, which was 63% of the Moyo River Basin area. From 2016 to 2017, the changes were dominated by the change magnitude value of 0.063, which was 58.6% of the Moyo River Basin area. From 2017 to 2018, changes were dominated by the change magnitude value of 0.084 of 55.26% of the Moyo watershed area. From 2018 to 2019, the change was dominated by the change magnitude value of 0.057, which was 47.57% of the Moyo watershed area. The direction of land cover change was dominated by Q2 in 2016, Q4 in 2017 and 2018, and Q2 and Q4 in 2019. These changes generally occurred in the Moyo watershed middle and downstream parts, which are grasslands. The use of the Conditional Change Vector Analysis (CCVA) approach in a tropical savanna environment can detect changes and the direction of change with an accuracy of about 70%.

The analysis of the watershed gives the surface area of land that rain streamed arrived in the river. The modern method to analyze the catchment is the ArcGIS program based on the Digital Elevation Model (DEM). The study area is An Najaf province, which area equaled about 27675 square kilometers. The HECGeoHMS (Hydrologic Engineering Center's Hydrologic Modeling System) is the link program on the ArcMap software that abled by serious steps to analyze the specific watershed. The auto analysis of the watershed area gives four basins for each outlet points located on the distributary Euphrates river. These four basins consisted of multi sub-basins and streams of rain flow. Basin 4 has the most significant volume, about 11.4% of the total case area of the basin, and the average slope is 3.2%. According to the amount of accumulative rainwater, basin 4 is essential when any obstruction is constructed at the end of the outlet point in the stream. This location of the construct is used to prevent the sediment in the Euphrates river and to avoid surface soil degradation. The arrangement of importance basin based on the advantage of water using to give maximum discharge and low evaporation is basin four at the first, basin two at the second.

We surveyed herpetofauna along the poorly-explored region of two watersheds of Kumoan Himalaya, Dabka and Khulgarh. Adaptive cluster method was used to collect forest floor reptiles, and stream transect was used for stream reptiles and amphibians. In total, 18 species of reptiles were recorded in two watersheds, with 15 and nine species recorded in Dabka and Khulgarh, respectively. Forest floor density of reptiles was 87.5/ha in Dabka and 77.7/ha in Khulgarh. In terms of species, Asymblepharus ladacensis and Lygosoma punctatus density were highest in Dabka and Khulgarh, respectively. Eight species of amphibians were recorded in Dabka with a density of 9.4/ha and four species in Khulgarh with density of 5.2/ha. In both watersheds, density of Euphlyctis cyanophlyctis was highest. Reptilian and amphibian diversity of Dabka was 1.52 and 1.23, respectively, and in Khulgarh 0.43 and 0.23, respectively. In both watersheds reptile density, diversity and richness decreased with increasing elevation. Reptile density showed a weak correlation with microhabitat features such as litter cover, litter depth, and soil moisture in both watersheds. Amphibian density was positively correlated with soil moisture, litter cover, and litter depth. Comparison showed that Dabka is richer and more diverse than Khulgarh, presumably because of the undisturbed habitat, broad and slow stream, and deeper forest litter of the former.

Daihai Lake (DL), the third largest inland lake in Inner Mongolia, has shrunk severely given the conditions of no significant decrease in annual precipitation. On the basis of field surveys and Landsat remote sensing images, this study analyzed land use and land cover (LULC) changes in six periods of the DL watershed area during 1986–2019. Then, with the combination of the LULC results and the Soil Conservation Service–Curve Number method, we discussed the change characteristics and influence factors of the surface runoff in the watershed and the reason for DL shrinkage. From 1986 to 2019, the water area of DL decreased rapidly at a rate of −2.22 km2/year, and the area of farmland and grassland in the watershed changed strongly along the opposite trend. The surface runoff in the DL watershed was reduced by approximately 513.6 million m3 during the last 34 years. In addition to local rainfall, groundwater is also an important water supply to the lake and accounts for a greater proportion. The average recharge rate of groundwater to the lake is approximately 64.55 million m3 per year in the past 34 years. The area change of the DL is related to the runoff reduction, huge evaporation, and lake water use in thermoelectric power generation. The local precipitation cannot enter the groundwater in DLW. Large-scale exploitation of external groundwater for agricultural irrigation and industrial production is another important cause of lake degradation.

A sense of concern for the environment, one of which is by planting tree seeds. On this community service activities this time, we planted tree seedlings in the Citarum Watershed (DAS), in Jelegong village, West Bandung. The location selection was based on the condition of the area which was damaged by human activities, including the conversion of land into a trash can. This tree planting activity has a negative impact on the surrounding environment. This activity was carried out before the pandemic, on November 24-25, 2019 involving the Budi Luhur University Academic Community as a form of concern for the environment. This activity also involves Jelegong Village Community and Officials as well as the TNI who served as the Sector 8 task force. The tree seedlings planted were fruit tree species such as mango, rambutan, jackfruit and others.The number of trees that planted spread across the watershed totaling 150 trees. The one, who is responsibility for the maintenance of this plant is a shared responsibility between the Budi Luhur University Community, this activity is expected to increase the awareness of the people of Jelegong Village about the importance of maintaining and conserving the balance of nature, especially in the watershed area in Jelegong Village.

Observations and modeling are used to assess potential impacts of sediment releases due to dam removals on the Hudson River estuary. Watershed sediment loads are calculated based on sediment-discharge rating curves for gauges covering 80% of the watershed area. The annual average sediment load to the estuary is 1.2 Mt, of which about 0.6 Mt comes from side tributaries. Sediment yield varies inversely with watershed area, with regional trends that are consistent with substrate erodibility. Geophysical and sedimentological surveys in seven subwatersheds of the Lower Hudson were conducted to estimate the mass and composition of sediment trapped behind dams. Impoundments were classified as (1) active sediment traps, (2) run-of-river sites not actively trapping sediment, and (3) dammed natural lakes and spring-fed ponds. Based on this categorization and impoundment attributes from a dam inventory database, the total mass of impounded sediment in the Lower Hudson watershed is estimated as 4.9 ± 1.9 Mt. This represents about 4 years of annual watershed supply, which is small compared with some individual dam removals and is not practically available given current dam removal rates. More than half of dams impound drainage areas less than 1 km2, and play little role in downstream sediment supply. In modeling of a simulated dam removal, suspended sediment in the estuary increases modestly near the source during discharge events, but otherwise effects on suspended sediment are minimal. Fine-grained sediment deposits broadly along the estuary and coarser sediment deposits near the source, with transport distance inversely related to settling velocity.

River sedimentation is an important indicator for ecological and geomorphological assessments of soil erosion within any watershed region. Sediment transport in a river basin is therefore a multifaceted field yet being a dynamic task in nature. It is characterized by high stochasticity, non-linearity, non-stationarity, and feature redundancy. Various artificial intelligence (AI) modeling frameworks have been introduced to solve river sediment problems. The present survey is designed to provide an updated account of the latest and most relevant AI-based applications for modeling the sediment transport in river basin systems. The review is established to capture the subsequent developments in the advanced AI models applied for river sediment transport prediction. Also, several hydrological and environmental aspects are identified and analyzed according to the results produced in those studies. The merits and constraints of the well-established AI models are further discussed in much detail, particularly considering state-of-the art, modeling frameworks and their application-specific appraisal, and some of the key proposed future research directions. Together with the synthesis of such information to drive a new understanding of models and methodologies related to suspended river sediment prediction, this review provides a future research vision for hydrologists, water scientists, water resource engineers, oceanography and environmental planners.

Constructed agricultural treatment wetlands are key tools for removing nitrate (NO3–) from surface waters. Due to limited funds for NO3– removal practices, investments need to be in the most cost-effective practices. Furthermore, NO3– removal practices that take less land out of production may be more appealing for farmers. Therefore, three types of wetlands were compared to determine NO3– removal effectiveness and cost effectiveness across a watershed. The three wetland types included large wetlands with drainage areas greater than 60 ha; small, edge-of-field wetlands with drainage areas covering fewer than 60 ha; and small, edge-of-field wetlands with a dual treatment system of surface treatment and subsurface treatment following infiltration. The Agricultural Conservation Planning Framework (ACPF) toolbox model was used to determine best placements for each wetland type in the Elm Creek watershed in southern Minnesota, United States. The Soil and Water Assessment Tool (SWAT) model was used to estimate the volume of tile discharge and nitrate-nitrogen (NO3-N) concentration into each wetland over a 10-year period. A spreadsheet model was used to estimate the reductions of NO3– in each wetland over the same 10-year period. Small, edge-of-field wetlands with a saturated hydraulic conductivity (Ksat) of 0.17 m d–1 were more effective at removing NO3– for the area removed from crop production in order to create the wetland (kg ha–1 y–1) and as cost effective (US$ kg–1 NO3-N removed) as the large wetlands. When the small wetlands had a low Ksat (8.64 × 10–5 m d–1), they were more effective for each area removed from crop production (p = 0.06) but not as cost effective (p = 0.003). This study suggests that constructing many small, edge-of-field treatment wetlands with high conductivity, dual-treatment systems to reach nutrient reduction goals would cost the same as constructing large wetlands but would remove fewer hectares of cropland from production. If landowners are interested in removing only a few hectares from crop production at a time, the wetland restoration would possibly still be beneficial. Minimum hectares should not be a limitation for restoration program enrollment as long as the wetland to watershed area ratio is still viable.

The Urban Agglomerations of Middle and Lower Reaches of the Yangtze River Economic Belt (UAMLYREB) have experienced rapid and intense urbanization over the past decades with natural ecosystems being converted to impervious surfaces. Thus, impervious surfaces are recognized as critical parameters when considering the effect of urbanization on water quality. While understanding how the threshold of impervious surfaces affects water quality has been a hot topic, there has been little quantitative analysis on how such thresholds change during rapid urbanization periods across large urban areas. To remedy this deficiency, this article made use of remotely-sensed impervious surface area data and in situ water quality monitoring observations for the period 2000 to 2018 to quantitively derive the temporal variation in the thresholds of the percentage of the impervious surface area (PISA) when inferring the relationship between PISA and a set of water quality indicators for a selection of watersheds within the UAMLYREB. We employed segmented regression model to derive the nonlinear relationship between PISA, the water quality indicators, and the PISA-related thresholds. Our results indicate that PISA may be considered a useful water quality indicator over watershed spatial scales. We also found that the threshold effects differed between water quality indicators (DO, CODMn, NH3-N), where, except for NH3-N, the indicators showed a PISA threshold of 30.08 to 42.34%, with slight variations over the study period. These results imply that maintaining PISA to be around 30% in watershed areas may be sufficient to mitigate against water quality degradation during the urbanization process.

Yarehalli micro-watershed lies between 750 51' 37.58'' to 750 53' 29.93'' East longitudes and 130 58' 59.95'' to 140 1' 3.72'' in Davanagere district of Karnataka. The drainage networks of micro-watershed were delineated from the Survey of India topographical map of 1:50,000 scale. ArcGIS software was used for evaluation of linear, areal and relief as pects of the micro- watershed. The present study reveals that, drainage pattern of the study area is dendritic with trunk order 4th. The watershed area, perimeter, maximum length and width of the watershed was 977 ha, 10.00 km, 4.40 km and 2.20 km respectively. The mean value of bifurcation ratio is 3.23, the micro-watershed have been suffered less structural disturbance and drainage pattern has not been distorted. The value of drainage density is 2.31 km km-2 which indicated that, the region is having permeable subsoil material and good vegetative cover. The value of form factor indicates micro-watershed is approaching towards elongated shape of watershed. The present study reveales that, GIS based approach in evaluation of geo-morphological characteristics is more appropriate than conventional techniques. Over all study suggests that the micro-watershed should be treated with soil and water conservation measures.

The landslide is one of the natural disasters which claim human lives and incur huge economic losses, especially in the mountainous area. The main aim of this study is to develop different zones of landslide-prone area using the index of entropy (IOE) at the Ossey watershed area in Bhutan. During the landslide inventory, 164 landslides were identified of which 115 locations were used for the training dataset while the remaining 49 locations were used for the validation dataset. A total of ten causal factors were used for this study including elevation, slope, aspect, slope curvature, stream power index, normalized difference vegetation index (NDVI), distance from the road, distance from the river, lithology, and rainfall. The IOE was used to obtain the relationship between the landslide events and the causal factors. The most influential causal factors were NDVI, slope, and rainfall with the weightage of 0.377, 0.347, and 0.175 respectively as per the IOE. The final landslide susceptibility map was classified into five classes using the geometrical interval classification. The validation was done using the receiver operating characteristic (ROC) curves and the kappa index. The area under the curve (AUC) for the success rate and prediction rate was 0.7821 and 0.8377, respectively. The kappa index using the training dataset and validation dataset were 0.4111 and 0.4898, respectively. The final landslide susceptibility map is accurate enough for the future references by the decision-makers and the engineers.

Pariwisata adalah sektor yang masih menjadi andalan penggerak pengembangan suatu kawasan. Kegiatan pariwisata ini akan menjadi primadona penggerak peningkatan ekonomi khususnya bagi kawasan yang memiliki potensi unik dan sumber daya langka. Kriteria kepemilikan potensi keunikan dan kelangkaan dapat ditemukan di Desa Cikoang Kecamatan Mangarabombang Kabupaten Takalar. Perpaduan suasana muara sungai dengan keasrian lingkungan dalam balutan temperatur udara yang nyaman didukung oleh ritual tahunan Maudu Lompoa dan hasil tangkapan ikan segar nelayan adalah potensi wisata yang sulit dilupakan bagi pelancong yang bercita rasa tinggi. Kondisi seperti ini tentunya patut untuk dibagi kepada seluruh masyarakat pencinta wisata dunia. Potensi tersebut sangat disayangkan karena lingkungannya telah menunjukkan adanya gejala penurunan kualitas lingkungan dan kurangnya fasilitas pendukung untuk membantu menampakkan keunggulannya. Penurunan kualitas lingkungan dan kekurangan fasilitas penunjang adalah permasalahan pengabdian ini. Sedangkan upaya untuk memunculkan potensi emas wisata desa muara tepi sungai adalah tujuan pengabdian. Metode yang digunakan untuk menyelesaikan masalah adalah pendekatan deskripsi arsitektural dengan pertimbangan kesatuan antara unsur budaya, wisata, pendidikan dan kuliner. Hasil kajian melahirkan gagasan tata ruang kawasan yang terintegrasi antara kegiatan budaya, pendidikan dan rekreasi. Penyelesaian kawasan tepi air muara sungai dengan konstruksi penahan erosi sebagai tempat wisata adalah solusi bernilai tambah gabungan. Peningkatan kawasan wisata tambak penggaraman sebagai gabungan wisata dan pendidikan. Peningkatan kawasan wisata budaya maudu lompoa sebagai gabungan wisata budaya. Penataan rancangan desa Cikoang berbasis wisata menghasilkan tatanan ruang dan rancangan arsitektural yang menggabungkan wisata budaya, pendidikan, kuliner, dan pemandangan muara sungai sebagai satu kesatuan yang terintegrasi akan mengantarkan Desa Cikoang menjadi kawasan wisata desa yang berkualitas tinggi.

One of the priority activities in Forest and Land Rehabilitation (FLR) program conducted by the Ministry of Environment and Forestry since 2010 is People’s Nursery Program/Kebun Bibit Rakyat (KBR). Jembrana Regency as one of the districts that participated in this program is an area with a diverse physical conditions and represents each watershed zone consisting of upstream, middle, and downstream, so it becomes interesting to study. This study aims to describe the KBR program in terms of changes in land use at the KBR location. The method used in this research was a qualitative descriptive approach referring to data on changes in land cover in 2009, 2013, and 2016 as an analysis material that represents the year before the program, the year when the program began, and the year when the program was harvested. The results of the study showed that there was a change in land cover at the locations during the implementation of the KBR program in Jembrana Regency, namely an increase in dry land forest area of 44.2 ha and mixed gardens of 252.5 ha. This shows that the KBR program has contributed to the RHL program in terms of increasing the area of vegetation and has involved the community in its implementation.

Artificial oasis could be supported by the trapping and retaining rainfall water by impermeable layer of artificial material. In case of average annual rainfall in Arabian or Pakistani Deserts of 100 mm the watershed area must be at least 1000 ha to ensure rainfall water supply for consumption and irrigation in the artificial oasis of 100 ha area. Minimum cost for the sealing of 1000 ha of the sand slopes with 1 mm geosynthetic liner is about 112 mln Saudi Arabian Riyal, which could be not acceptable price for 100 ha of artificial oasis land. However, this cost could be diminished to 17 mln Saudi Arabian Riyal if to coat watershed slopes with 1 mm of biocemented sand crust using a low viscosity solution of biocement. Conventional cementation is cheaper but it cannot be used to make 1 mm sand crust because of a high viscosity of the cement suspension. The novel biotechnological method is based on the formation of the sand surface crust for water collection and transportation on the surrounding slopes. Most environmentally friendly biotechnology for this biocementation is aerobic biooxidation of cheap calcium formate or calcium acetate. Biocementation of the sand crust could be used to make a low-cost artificial desert oasis fed by rainfall.

The Abuan watershed had experienced deforestation due to illegal deforestation, poaching and land conversion. This has resulted to the loss of its ecosystem services. In the watershed area, restoration efforts showed encouraging results where secondary forest is flourishing. Secondary forest growth provides tremendous potential for large amounts of carbon sequestration.This study aimed to determine the carbon sequestration potential of the secondary growth forest along Abuan watershed in Ilagan, Isabela. Specifically, it was conducted to identify the tree species present in the area and estimate the amount of carbon sequestered annually by the above ground carbon cover of the trees in the study area. Ten (10) sampling points measuring 20m x 20m were established using Point center quarter method (PCQM). Tree census was conducted and identification was done up to its species level. The amount of carbon sequestered by the trees was measured.Twenty six (26) species was documented. The above ground carbon by the trees in the watershed is calculated at 18,452 kg. The species Shorea concorta (White lauan) has the highest amount of carbon sequestered while Dipterocarpus validus (Hagakhak) species sequestered the lowest. The age, height and DBH are directly proportional to the amount of carbon sequestration. Thus, the younger the tree, the higher the amount of carbon sequestered and the older the tree, the lower the amount of carbon sequestration. In addition, the taller and wider the tree, the higher carbon sequestration potential per year. It is recommended that below ground potential including the carbon-sink function of the soil be included in estimating the carbon sequestration potential of the secondary growth forest to understand fully this ecosystem function.

Rainfall-runoff relationship in arid regions is unique and challenging to study. Studies for bridging the hydro-meteorological knowledge gap for planning, designing and managing water resources is therefore vitally important. The objective of this study is to develop a method for estimating unit hydrograph at reasonably finer time resolutions (10-min and 1-h) which can be easily adaptable by practitioners at sub-catchment levels, especially when the focus area is ungauged. Observed wadi-flow at 5-min interval and tipping bucket rainfall measurements at 1-min interval were obtained to cover 10 major watersheds in Oman. The deconvolution method was applied to derive the unit hydrographs (UHs) from wadi-flow and excess rainfall. Key catchment characteristics such as the watershed area, length of the main wadi and the length to the centroid of the catchment area were derived from digital elevation model (DEM) data. The whole study area was then divided into 515 sub-catchments with various shapes and sizes. A strong relationship was found between the wadi length and the length to the centroid of the catchment area (R2>0.89). This relationship was then adopted to simplify the classical Snyder method to determine UHs. Moreover, several parameters of the Snyder method were calibrated to the arid environment by matching the peak-flow, lag-time and three time-widths (75%, 50% and 30% of the peak-flow) of 10-min and 1-h UHs with physical characteristics of the watersheds. All developed relationships were validated with independent rainfall and wadi-flow events. Results indicate that the calibrated parameters in these arid watersheds are quite distinct from those suggested for other regions of the world. A marked difference was found between the 10-min UHs estimated by the S-hydrograph method and the deconvolution method. Therefore, it is concluded that a method depends on natural hydro-meteorological conditions would be more practical in arid region. The proposed methodology can be used for water resources management in arid regions having similar climate and geographical settings.

Wildfires are landscape scale disturbances that can significantly affect hydrologic processes such as runoff generation and sediment and nutrient transport to streams. In Fall 2016, multiple large drought‐related wildfires burned forests across the southern Appalachian Mountains. Immediately after the fires, we identified and instrumented eight 28.4–344 ha watersheds (four burned and four unburned) to measure vegetation, soil, water quantity, and water quality responses over the following two years. Within burned watersheds, plots varied in burn severity with up to 100% tree mortality and soil O‐horizon loss. Watershed scale high burn severity extent ranged from 5% to 65% of total watershed area. Water quantity and quality responses among burned watersheds were closely related to the high burn severity extent. Total water yield (Q) was up to 39% greater in burned watersheds than unburned reference watersheds. Total suspended solids (TSS) concentration during storm events were up to 168 times greater in samples collected from the most severely burned watershed than from a corresponding unburned reference watershed, suggesting that there was elevated risk of localized erosion and sedimentation of streams. NO₃‐N concentration, export, and concentration dependence on streamflow were greater in burned watersheds and increased with increasing high burn severity extent. Mean NO₃‐N concentration in the most severely burned watershed increased from 0.087 mg L⁻¹ in the first year to 0.363 mg L⁻¹ (+317%) in the second year. These results suggest that the 2016 wildfires degraded forest condition, increased Q, and had negative effects on water quality particularly during storm events.

Flooding is one of the problems that often occurs in the DKI Jakarta area, which one of the causes is the change of land use in watersheds that were originally into development areas. Whereas, its often the cross section of the river will be disrupted due to the loss of the riverbanks and the narrower cross section of the river. In order to overcome this, the Jakarta Provincial Government in 2013 normalized several rivers that crossed the DKI Province and one of them was the Pesanggrahan River which will be further investigated. The purpose of this study is to analyze the effect of river normalization on erosion and sedimentation which will result in changes in the longitudinal and cross section of the river. To get an accurate map of the Watershed Area, Arc-GIS software is used while identification of river flow before and after normalization was carried out based on data from Central Office of River Region Ciliwung-Cisadane, Ministry of Public Works. Sediment samples were taken at 3 points on the river, upstream, middle and downstream, that were reviewed to determine the gradation of the sediment grains. The HEC-RAS application is used to simulate sediment transport on the river section before and after normalization. The simulation results are used to determine the cross section changes due to erosion and sedimentation and to determine the water level in the river. From the water level, the hydraulic radius can be calculated and then carried out sediment transport calculation using Ackers-White equation since the equation using grain distribution from range 0.02 – 4.94 mm. The results it was found that the sediment transport in the upstream point increased 155.11 tons / year, at the midpoint increased 89.64 tons / year and the downstream point decreased 0.28 tons / year.

Debris flow activity increased after the Wenchuan earthquake, and many debris flows continue to occur. Recently, a catastrophic debris flow event was triggered by strong rainfall on 20 August 2019 in Wenchuan County, China. The main purposes of this article are to analyse the activity characteristics of this disaster and further to analyse the long-term activity of debris flow in Wenchuan County based on the analysis results of this disaster. According to a field survey and remote sensing image interpretation, this strong rainfall triggered 15 debris flows that occurred simultaneously in the large watershed in northern Wenchuan County, and they were characterised by strong channel erosion and a disaster chain effect. The activity and sediment supply capacity of landslides have decreased significantly, and the landslides that provided materials for this debris flow event are mainly distributed on both banks of tributaries. The amounts of triggering rainfall and antecedent accumulated rainfall for this debris flow event were 13.7 mm and 47.1 mm, respectively. In addition, the channel runoff formed by strong short-duration rainfall eroded the channel deposits, and temporary check dams failed due to slope failures; these are the main causes for debris flows in the next period. Analyses of the debris flow volume versus watershed area and the maximum erosion modulus prove that the debris flow activity in Wenchuan County is decreasing with time, but more than 5~10 years will be required to recover to the pre-earthquake level.