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Integrated assessment of the watershed is critical in arid and semi-arid areas due to the severe water stress in these regions. Data and information are an essential part of decision making and water governance to obtain integrated water resources management at the watershed scale. Water accounting is a helpful tool to organize information and present them as the standard indicators to achieve this goal. Therefore, the objective of this study is to implement the Water Accounting Plus framework (WA+) in the Ferizi watershed located in the Khorasan-e Razavi Province. In this study, water accounting indicators of the Ferizi watershed for a period of 28 years (1990-2017) and wet (1990-1997) and dry (1998-2009) periods were calculated using the SWAT model. The calculated indicators showed that the amount of manageable water and usefulness of consumption (transpiration) is low in the watershed and a large part of the share of irrigation in the watershed is provided by groundwater resources. Generally, the results of this study showed that the use of the SWAT model, WA+ framework, and analysis of water accounting indicators play a significant role in assessing the agricultural and hydrological conditions of the watershed. The proposed approach in this study can help managers make enlightened decisions to keep the sustainability of the watershed.

Forests, traditional gardens and green spaces play an important role in regulating the water flow of an area. Along with the high demand for land in Bali for agriculture and tourism, many forest areas have been converted into hotels and settlements. Forest conversion has caused many problems such as erosion, soil fertility decreased, flora fauna extinction, floods, drought, global warming and the disturbing watershed, especially rivers for springs. The purpose of this study is the development of watershed conservation in Bali based on traditional agroforestry. The method that used is vegetation analysis. Calculation of the erosion amount using the USLE formula. Sampling was done by ten plots. The results showed that traditional agroforestry vegetation consisted of vertical and horizontal structures. The characteristic of traditional agroforestry is that dominant plants are distributed irregularly, thus creating a miniature structure like a forest. The vertical structure consists of trees, horizontal structure filled with species of garden plants and agriculture. Trees have roots spread intensively in the soil and reduce nutrient leaching. Land cover by vegetation protects the soil and erosion. The agroforestry has a role as an act of soil and water conservation. Traditional agroforestry land cover has a relatively low C coefficient (0.05-0.25) compared to other lands. The level of erosion hazard is low and moderate. Average erosion value of 55.01 t.ha-1.yr-1. This indicates that traditional agroforestry makes the soil have a higher ability to absorb water, thereby reducing surface runoff. Likewise, organic material that improves the water content capacity. In addition, water quality can be improved through the humus filter function. During a long dry season, there is a drought due to low rainfall, but rivers and springs were able to supply water for the peoples daily needs. This condition occurs because of the tree retentions in traditional gardens. Conservation actions need to be taken, namely maintaining trees vegetation, increasing reforestation, bench terraces use, mounds and mulch use. This condition also places traditional agroforestry as a sustainable land management system.

Global warming influencing regional climate is playing a significant role in triggering recurrent drought. The current study demonstrates a PCA (Principal Component Analysis) driven watershed prioritization in a part of Koel river basin by runoff computation during monsoon season along with assessment of Vegetation Health Index (VHI) derived from MODIS satellite data during the period from 2000 to 2017. Koel river catchment area of 7,261 sq km was divided into 82 sub-watersheds based on drainage networks derived from a Survey of India (SOI) topographical map at scale 1: 50,000. High resolution satellite image of Sentinel-2 was used to prepare a land use land cover map. Soil conservation service curve number method (SCS CN) was used to estimate runoff. The result obtained from runoff estimation of 82 sub watersheds shows high runoff (50 to 60% of rainfall) with 290,000 m3 total runoff volume in the upper and middle parts of the catchment dominated by agricultural/fallow and barren lands, whereas low runoff was estimated (20 to 30%) with 29,467 m3 in the lower catchments where a large area is covered with forests. The value of satellite based VHI ranges between 23 to 53 with major parts of the area exhibiting values less than 30, reflecting poor vegetation health. Most of the sub-watersheds in parts of Ranchi, Lohardaga, Gumla and Khunti districts experienced high total runoff, with poor vegetation health index reflecting more proneness to drought. Watershed prioritization was done based on correlation among four parameters viz., rainfall, drought zones, direct runoff and total runoff through PCA. Strong correlation between total runoff volume and drought areas was used for watershed prioritization, which indicated 42 sub-watersheds (4,703 sq km) in the upper catchment required high prioritization. The outcomes of the study would help proper planning of water resources and soil moisture management to overcome the recurrent drought conditions at watershed level. HIGHLIGHTS Runoff estimation of 82 sub-watersheds has been done.; High runoff volume has been demarcated in the upper and the central part of the study area.; Areas with poor vegetation conditions have been highlighted by using drought indices.; Watershed prioritization using Principal Component Analysis by considering factors - rainfall, drought, direct runoff and total runoff - indicated that a major part of the study area is exhibiting high runoff and is severely affected by drought and therefore urgently needs watershed management based on prioritization.;

In this article, we develop a novel feature extraction method that combines two well-established mathematical morphology concepts: watersheds and morphological attribute profiles (APs). In order to extract spatial-spectral features from remote sensing data, APs were originally defined as sequences of filtering operators on inclusion trees, i.e., the max- and min-trees, computed from the input image. In this study, we extend the AP paradigm to the more general framework of hierarchical watersheds. Moreover, we explore the semantic knowledge provided by labeled training pixels during different phases of the watershed-AP construction, namely within the construction of hierarchical watersheds from the raw image and later within the filtering of the resulting hierarchy. We illustrate the relevance of the proposed method with two applications including land cover classification and building extraction using optical remote sensing images. Experimental results show that the new profiles outperform various existing features using two public datasets (Zurich and Vaihingen), thus providing another high potential feature extraction method within the AP family.

Abstract River networks are important features in surface hydrology. However, accurately representing river networks in spatially distributed hydrologic and Earth system models is often sensitive to the model's spatial resolution. Specifically, river networks are often misrepresented because of the mismatch between the model's spatial resolution and river network details, resulting in significant uncertainty in the projected flow direction. In this study, we developed a topological relationship‐based river network representation method for spatially distributed hydrologic models. This novel method uses (a) graph theory algorithms to simplify real‐world vector‐based river networks and assist in mesh generation; and (b) a topological relationship‐based method to reconstruct conceptual river networks. The main advantages of our method are that (a) it combines the strengths of vector‐based and DEM raster‐based river network extraction methods; and (b) it is mesh‐independent and can be applied to both structured and unstructured meshes. This method paves a path for advanced terrain analysis and hydrologic modeling across different scales.

ABSTRACT Watersheds that supply residents with drinking water have the potential for contamination with Cryptosporidium oocysts. To evaluate any potential similarities between Cryptosporidium species previously found in the New York City (NYC) watershed and those causing disease in NYC, the species were identified in stool specimens from residents with cryptosporidiosis. Genetic analysis was performed on 628 positive stool samples collected from NYC residents between 2015 and 2018 to determine the species present. A total of 547 samples yielded positive results by real-time PCR. Of these samples, 512 (93.6%) were identified to the species level, with 94.7% positive for either Cryptosporidium hominis or Cryptosporidium parvum (56.4% and 38.5%, respectively), including one coinfection. Less common Cryptosporidium species identified included C. felis, C. canis, C. ubiquitum, C. meleagridis, and a Cryptosporidium sp. chipmunk genotype. Results were evaluated and compared to species and genotypes of Cryptosporidium previously identified from stormwater collected within the NYC watershed. While there was overlap with some of the rare species found in case specimens, the prevalence and distribution of species did not suggest a connection between sources previously identified in the watershed and the species causing human cases of cryptosporidiosis in NYC residents. IMPORTANCE It is important to identify the species causing human cryptosporidiosis in a population in order to investigate possible sources or routes of contamination. Many species of Cryptosporidium are host-adapted and therefore have the potential to be tracked back to specific sources that can subsequently be managed. There has been no evidence to suggest that the water supply has ever been a source of cryptosporidiosis cases in NYC, and since 2013, the New York City Department of Environmental Protection has further reduced the risk of disease through the use of ultraviolet treatment to inactivate any Cryptosporidium present in the source water. However, as one of the largest unfiltered water supplies in the country, it is important to evaluate watershed sources for potential impacts to public health. In this unique study, species of Cryptosporidium causing disease in NYC residents were identified and compared with previously identified species from the watershed.

We examined ice-nucleating particles (INPs) in the plumes of the Tocantins and Amazon rivers, which drain watersheds with different proportions of degraded land. The concentration of INPs active at −15°C (INP−15) was an order of magnitude lower in the Tocantins (mean = 13.2 ml−1; s.d. = 7.8 ml−1), draining the more degraded watershed, compared with the Amazon (mean = 175.8 ml−1; s.d. = 11.2 ml−1), where the concentration was also significantly higher than in Atlantic surface waters (mean = 3.2 ml−1; s.d. = 2.3 ml−1). Differences in heat tolerance suggest that INPs emitted by the Amazon rainforest to the atmosphere or washed into the river might originate from contrasting sources on top of and below the rainforest canopy, respectively. For the Amazon River, we estimate a daily discharge of 1018 INP−15 to Atlantic waters. Rivers in cooler climate zones tend to have much higher concentrations of INPs and could, despite a smaller water volume discharged, transfer even larger absolute numbers of INP−15 to shelf waters than does the Amazon. To what extent these terrestrial INPs become aerosolized by breaking waves and bubble-bursting remains an open question.

Escherichia coli (E. coli) level in streams is a public health indicator. Therefore, being able to explain why E. coli levels are sometimes high and sometimes low is important. Using citizen science data from Fall Creek in central NY we found that complementarily using principal component analysis (PCA) and partial least squares (PLS) regression provided insights into the drivers of E. coli and a mechanism for predicting E. coli levels, respectively. We found that stormwater, temperature/season and shallow subsurface flow are the three dominant processes driving the fate and transport of E. coli. PLS regression modeling provided very good predictions under stormwater conditions (R2 = 0.85 for log (E. coli concentration) and R2 = 0.90 for log (E. coli loading)); predictions under baseflow conditions were less robust. But, in our case, both E. coli concentration and E. coli loading were significantly higher under stormwater condition, so it is probably more important to predict high-flow E. coli hazards than low-flow conditions. Besides previously reported good indicators of in-stream E. coli level, nitrate-/nitrite-nitrogen and soluble reactive phosphorus were also found to be good indicators of in-stream E. coli levels. These findings suggest management practices to reduce E. coli concentrations and loads in-streams and, eventually, reduce the risk of waterborne disease outbreak.

Changes in climate are driving an intensification of the hydrologic cycle and leading to alterations of natural streamflow regimes. Human disturbances such as dams, land-cover change, and water diversions are thought to obscure climate signals in hydrologic systems. As a result, most studies of changing hydroclimatic conditions are limited to areas with natural streamflow. Here, we compare trends in observed streamflow from natural and human-modified watersheds in the United States and Canada for the 1981-2015 water years to evaluate whether comparable responses to climate change are present in both systems. We find that patterns and magnitudes of trends in median daily streamflow, daily streamflow variability, and daily extremes in human-modified watersheds are similar to those from nearby natural watersheds. Streamflow in both systems show negative trends throughout the southern and western United States and positive trends throughout the northeastern United States, the northern Great Plains, and southern prairies of Canada. The trends in both natural and human-modified watersheds are linked to local trends in precipitation and reference evapotranspiration, demonstrating that water management and land-cover change have not substantially altered the effects of climate change on human-modified watersheds compared with nearby natural watersheds.

Source apportionment is critical for guiding development of efficient watershed nitrogen (N) pollution control measures. The ReNuMa (Regional Nutrient Management) model, a semi-empirical, semi-process-oriented model with modest data requirements, has been widely used for riverine N source apportionment. However, the ReNuMa model contains limitations for addressing long-term N dynamics by ignoring temporal changes in atmospheric N deposition rates and N-leaching lag effects. This work modified the ReNuMa model by revising the source code to allow yearly changes in atmospheric N deposition and incorporation of N-leaching lag effects into N transport processes. The appropriate N-leaching lag time was determined from cross-correlation analysis between annual watershed individual N source inputs and riverine N export. Accuracy of the modified ReNuMa model was demonstrated through analysis of a 31-year water quality record (1980–2010) from the Yongan watershed in eastern China. The revisions considerably improved the accuracy (Nash-Sutcliff coefficient increased by ∼0.2) of the modified ReNuMa model for predicting riverine N loads. The modified model explicitly identified annual and seasonal changes in contributions of various N sources (i.e., point vs. nonpoint source, surface runoff vs. groundwater) to riverine N loads as well as the fate of watershed anthropogenic N inputs. Model results were consistent with previously modeled or observed lag time length as well as changes in riverine chloride and nitrate concentrations during the low-flow regime and available N levels in agricultural soils of this watershed. The modified ReNuMa model is applicable for addressing long-term changes in riverine N sources, providing decision-makers with critical information for guiding watershed N pollution control strategies.

Source apportionment is critical for guiding development of efficient watershed nitrogen (N) pollution control measures. The ReNuMa (Regional Nutrient Management) model, a semi-empirical, semi-process-oriented model with modest data requirements, has been widely used for riverine N source apportionment. However, the ReNuMa model contains limitations for addressing long-term N dynamics by ignoring temporal changes in atmospheric N deposition rates and N-leaching lag effects. This work modified the ReNuMa model by revising the source code to allow yearly changes in atmospheric N deposition and incorporation of N-leaching lag effects into N transport processes. The appropriate N-leaching lag time was determined from cross-correlation analysis between annual watershed individual N source inputs and riverine N export. Accuracy of the modified ReNuMa model was demonstrated through analysis of a 31-year water quality record (1980–2010) from the Yongan watershed in eastern China. The revisions considerably improved the accuracy (Nash-Sutcliff coefficient increased by ∼0.2) of the modified ReNuMa model for predicting riverine N loads. The modified model explicitly identified annual and seasonal changes in contributions of various N sources (i.e., point vs. nonpoint source, surface runoff vs. groundwater) to riverine N loads as well as the fate of watershed anthropogenic N inputs. Model results were consistent with previously modeled or observed lag time length as well as changes in riverine chloride and nitrate concentrations during the low-flow regime and available N levels in agricultural soils of this watershed. The modified ReNuMa model is applicable for addressing long-term changes in riverine N sources, providing decision-makers with critical information for guiding watershed N pollution control strategies.

Urbanization is thought to decrease riparian tree canopy cover, but this outcome may vary depending on geographic context. We examined changes in land cover and riparian tree canopy near Sacramento, California, a Mediterranean climate region impacted by agriculture before urbanization. We used aerial imagery to quantify changes in land cover and the area, width, and density of riparian tree canopy between 1937 and 2014 for the 85-km2 Arcade Creek watershed. While watershed land cover shifted almost entirely from pasture and crops to urban development, riparian forested area increased by 38 percent. The median width of riparian tree canopy more than doubled, and the density along smaller streams increased significantly (p < 0.0001). We used multiple data sources to examine potential drivers of these changes. Stream gage data and field observations indicated that the formerly intermittent Arcade Creek stream network receives spatially and temporally variable dry-season flow subsidies from urban runoff, but widespread channel incision may limit the impact of subsidies on riparian vegetation. Accordingly, sampling of riparian woody plants showed few hydrophilic species growing along these streams. Instead we found evidence of native oak regeneration and a high density of escaped horticultural species. The increase in riparian forest cover was thus likely due to changes in vegetation management and species composition from land use conversion, possibly augmented by increased dry-season water availability. The changes in canopy cover we quantified stand in contrast to the accepted pattern of riparian forest decline with urbanization, and are expected to affect ecosystem services.

To address present‐day issues with its water treatment facility while planning for operations and infrastructure that would endure, a Massachusetts water utility carefully designed a sustainability plan with true staying power. [ABSTRACT FROM AUTHOR]

The five watersheds of the Upper Jhelum Basin (UJB) in the Kashmir Himalaya, India has flood prone hydrographic features resulting in high-frequency of flooding in the basin. With this in mind, HEC-HMS was calibrated to estimate excess-runoff potential of five watersheds and the model results showed a good agreement with the observed streamflow. The study revealed that due to the presence of rocky-outcrops, precipitous-topography and impervious-surfaces, Vishav, Lidder and Sandran are the major contributors of the excess-runoff among the 5 watersheds as compared to Bringi and Kuthar. For the model-efficacy, the excess-runoff potential and the social-vulnerability of the region were compared to the floodwater-depth observed during the 2014-flooding event. The comparison reveals that the flood-vulnerability assessment of the UJB are well corroborated by the observed floodwater levels and the Vishav watershed is most vulnerable. The findings of this study are expected to inform flood management plans in the UJB. [ABSTRACT FROM AUTHOR]

Given the absence of soil loss indicators within the Land Degradation Neutrality (LDN) framework, this study integrates land cover suitability, soil erosion and sediment transport as complementary Mediterranean-tailored indicators. The 309km² Lebanese Nahr Ibrahim basin was chosen for this purpose. Land cover suitability was determined by combining land capability-land cover maps, while soil erosion and sediment transport were assessed using the CORINE and SWAT models, respectively. Under current conditions, the following was found: a 34.84% land cover suitability; 4% low, 39.55% moderate and 56.45% high soil erosion risks zones, and 2.85% low, 26% moderate and 68.15% high sediment yields zones. Through the LDN response strategy based land use plan, land cover suitability increased by 26.54%, while soil erosion risks changed by: -3.1% low, -10.85% moderate and -18% high risk zones. For sediment transport, changes were: 0% low, -10.85% moderate and -18% high risk zones, hence the multi-effectiveness of LDN. [ABSTRACT FROM AUTHOR]

Urbanization and agriculture increase the risk of water contamination in watersheds. A special concern arises when this water is used for public supply. Conventional hydrochemical methods have been applied to identify contaminants in bulk water; however, there is lack of investigation of their origins. Environmental isotopes can be used to address such knowledge gap by tracking the harmful substance back to its origins. This study evaluates the interference of urbanization as well as inorganic fertilizers in the suspended sediments of the tributaries of two impoundments, whose water supplies 72% of the municipality of Caxias do Sul, Southern Brazil. To achieve this goal, the isotopic ratios 87Sr/86Sr, 208Pb/204Pb, 206Pb/204Pb, 207Pb/204Pb, 208Pb/206Pb and 207Pb/206Pb were selected as geochemical tracers, showing promising results to evaluate sources of contamination in source water. The results of strontium isotopes showed two distinct groups, one marked by the geogenic origin of the sediment and the other by inorganic fertilizers. Lead isotopes indicated that suspended sediments have signatures compatible with the rocks that occur in the region and are in a range of isotopic ratios different from fertilizers or copper sulfate. [ABSTRACT FROM AUTHOR]

The present study undertakes to produce the land use/land cover map and to explore the change detection analysis of Noyyal watershed, Coimbatore, for a time period of 18 years. Based on the remote sensing and geographical information system for monitoring the temporal variations of land use/land cover, multi-temporal Landsat satellite 30-m spatial resolution images of Landsat 4/5 MSS and TM (1999), Landsat 7 ETM + (2008), and Landsat 8 Operational Land Imager (OLI) were obtained from the USGS website. The satellite images were geocoded into the universal transverse mercator (UTM) coordinate system zone 43 N. The unsupervised classification method was done by using an iterative self-organizing data analysis algorithm to compare the images and to classify the images into various land cover categories. Kappa statistics were used to assess the validation of the present study. The analysis suggests the total forest covered in 1999 was 22.69% and that of 2008 was 24.04% and reduced to 6.09%, in 2017. The agricultural land of 17.8% is reduced to 3.11% in 2008 and 0.86% in 2017. The settlements increased from 15.59 to 24.21% in 2008 and 27.14% in 2017. Increase in deforestation leads to increase in barren land. In 1999, the percentage of barren land was 17.2%; in 2008, it was 13.19%, and 50.93% in 2017. The overall accuracy estimation of the study is 73.19% and Kappa coefficient is 0.72. This study has proven a substantial strength of agreement for the map of 2017 from the result of validation rating criteria of Kappa statistics. [ABSTRACT FROM AUTHOR]

Many ecosystem services (ES) are provided by watersheds to downstream populations at no cost to them. To ensure sustainability, those who benefit from these services should be engaged in the protection and management of the watershed. The Mt. Banahaw de Lucban (MBdL) provides non-market values that are not considered in management planning; thus, the underestimation of its ES adversely affects its provisioning capabilities. Adding to this shortcoming is the insufficiency of funds to sustain the current watershed conservation initiatives. This study assesses the value that domestic water users have for sustained water supply resulting from the improved conservation of the MBdL watershed through contingent valuation. The willingness to pay (WTP) of 500 respondents from Lucban, Pagbilao, and Lucena City was estimated using logit regression to develop the model. Results revealed that 95% of the respondents voted yes to the referendum and that about 65% support the improved watershed conservation program. Bid amounts, years of education, household size, occupation, and income have a significant influence on WTP. The mean WTP estimate is PHP 71.53/household/mo. The approximate present amount of improved MBdL conservation is PHP 21.50M/yr. The net present value is estimated at PHP 76 M for five years. The potential fund, if collected, may contribute to the sustainability of any watershed conservation program for MBdL. [ABSTRACT FROM AUTHOR]

This study determines the most cost‐effective selection and location of Best Management Practice (BMP) scenarios for farmlands to reduce soil erosion and the delivery of sediment and phosphorus to the Fort Cobb Reservoir watershed under current and future climate scenarios. Using the Soil and Water Assessment Tool, detailed conservation practices (conservation tillage, contour farming, no‐tillage, and terracing) are simulated to determine crop yields, sediment, nitrogen, and phosphorus loss of three crops (winter wheat, irrigated cotton, and pasture) by each land use unit (hydrologic response units) and location in the watershed. An economic model is used to determine the cost‐minimizing choice of BMP scenarios for each land‐use unit that meets 50%, 75%, and 90% reduction of sediment, nitrogen, and phosphorus loads and the impact of climate change on the net return to farmers. Results indicate that the effective spatial placement of BMP scenarios is not the same under different climatic conditions. The average optimal net return to farmers ranges from 170.39 to 316.32 $/acre for all the scenarios. The shadow prices vary from 2.36 to 17.78 $/ton/acre of sediment abated. Although individual BMP scenario is effective in reducing sediment loads, combined BMP scenarios achieve higher performance. This work will help guide policymakers and farmers in decision‐making for the future regarding water quantity used and water quality downstream in the recreation area of the Fort Cobb Reservoir. [ABSTRACT FROM AUTHOR]

This study is to establish a new approach to estimate river salinity of semi‐arid agricultural watershed and identify drivers by using hydrologic modeling and machine learning. We augmented the limitations of the Soil and Water Assessment Tool (SWAT) to model salinity by coupling with eXtreme Gradient Boosting (XGBoost), a decision‐tree‐based ensemble machine learning algorithm. Streamflow, precipitation, elevation, main reach length, and dominant soil texture of the top two layers were used along with NO3, NO2, and total phosphorus (TP) output from a calibrated SWAT model are used as predictors to Total Dissolved Solids (TDS) in the XGBoost algorithm. Then, the SWAT model simulations of streamflow, NO3+NO2, and TP from 2000 to 2015 are used as inputs of the XGBoost model to predict monthly water TDS distribution along the river. The predicted river water TDS showed a higher concentration as going downstream from El Paso (inlet) through the Hudspeth canal to Fort Quitman (outlet). Finally, this study carried out cause analysis focusing on soil physical characteristics. The soil salinity level is directly affected by the soil permeability and irrigation water. As a result, the highest TDS is shown in sites with silt loam, whereas the lowest TDS was shown in sites with very cobbly soil. Silt soils can hold more water and are slower to drain than soils of a sand type. These analyses can be used to better understand the mitigation of water salinity. [ABSTRACT FROM AUTHOR]

The Brazilian Cerrado biome provides relevant ecosystem services for Brazil and South America, being strategic for the planning and management of water resources as well as for agribusiness. The objective was to evaluate the water quality along the course of the Córrego da Formiga in a virgin portion of the Brazilian Cerrado, the relationship of land use with physical-chemical and biological parameters of the water, and the inflow of the tributary. Five water collection points were defined (between the source and mouth) and observed on a quarterly scale in 2015, water samples were collected and analyzed for physical-chemical and biological parameters in the laboratory, and flow measurements were performed at the same point and day of water collection. To identify and quantify land use and land cover (LULC) in the watershed, an image from the Landsat8-OLI satellite was obtained, and other geomorphological data from hypsometry (Topodata-INPE) were obtained to generate the slope, basin delimitation, and contribution area for each water collection point. The LULC percentages for each area of contribution to the water collection points were correlated with the physical-chemical and biological parameters of the water and submitted to multivariate analysis (PLS-DA) for analysis and grouping among the five analyzed points. Changes in water-quality patterns were more pronounced concerning the time when the first and last sampling was performed (rainy period) and may be influenced by the increase in the volume of water in these periods. The stream flow is highly variable over time and between points, with the lowest recorded flow being 0.1 L s−1 (P1) and the highest being 947.80 L s−1 (P5). Córrego da Formiga has class III water quality (CONAMA resolution 357), which characterizes small restrictions on the use of water for multiple uses. The soil cover with native vegetation is just over 12%, while the predominance was of the classes of sugar cane (62.42%) and pasture (19.33%). The PLS-DA analysis allowed separating the water analysis points between P1, P2, P3, and P5, while P4 was superimposed on others. It was also possible to verify that the parameters that weighed the most for this separation of water quality were pH, alkalinity_T, alkalinity_h, calcium, and hardness, all with a tendency to increase concentration from the source (P1) to the mouth (P5). As for water quality, it was also possible to verify that points P2 and P5 presented better water-quality conditions. [ABSTRACT FROM AUTHOR]

This research dealt with the topic of modeling the soil lost in a semi-arid desert area in the Ma'an watershed and its surroundings in Ma'an Governorate using the global equation model, GIS, and remote sensing technology. Erosion is one of the most important geomorphological processes, and its intensity varies according to its causative factors. Soil erosion risks were assessed by applying a mathematical model within the GIS environment based on six factors affecting soil erosion. To apply the RUSAL model to the study area, a number of variables and factors must be derived based on the data of rainfall rates, land uses, soil characteristics, slope values, and vegetation index (NDVI). Several layers were established for the previous factors and then combined to produce a map for evaluating the risk of erosion, which was divided into five degrees. The results showed that only 0.004% of the study area falls within the severe and very severe classes, and 99.29% of the study area falls within the very light class, which reflects a very low susceptibility to erosion. The results also showed that rainfall and the topographic factor, which includes the degree of slope, contribute effectively to the occurrence of water erosion in the studied area. The study also proved that geographic information systems and remote sensing technology are effective tools in mapping soil and its related problems, especially that of water erosion. [ABSTRACT FROM AUTHOR]

Lorem Along with climate change, natural disasters will occur more frequently such as floods. Floods that occur in watersheds which include various human activities, such as Mata Allo (Indonesia) will especially cause a large enough impact. The elongated shape of the watershed has a slow response to peak discharge and time lag. The Mata Allo watershed is dominated by slopes above 25%→45% (65%) and agricultural land use which accounts for 53% of the area, which has an obvious impact on the amount of runoff and erosion that occurs. The eroded soil will be carried away by surface runoff and deposited in the plains between mountains and river floodplains. Based on the results of the study, the Topographic Wetness Index (TWI) map indicates that the part between the mountains and the floodplain around the Mata Allo river had a high TWI value. A high TWI value indicates a high vulnerability to anticipate flooding in the event of overflowing from the Mata Allo River. River morphometry, land use, and hydrological behavior in a watershed are closely related to the TWI value in the Mata Allo watershed. [ABSTRACT FROM AUTHOR]

Advanced methods for flood susceptibility mapping are required to minimize hazards in the watershed. Here, Partial Least Square-Structural Equation Model (PLS-SEM) was introduced to analyze the impact of flood influencing factors. PLS-SEM integrated with four Machine Learning (ML) methods as Multi-Layer Perceptron Neural Network (MLPNN), K Nearest Neighbor (KNN), Support Vector Machine (SVM) and Radial Basis Function Neural network (RBFN). In addition, significant flood influencing factors from PLS-SEM analysis was taken as the input of ML models. Then SVM, MLPNN, KNN, and RBFN integrated with the PLS-SEM classifier to develop hybrid models for constructing FSM. The performance of models is assessed in terms of standard statistical methods. The performance of the achieved model is good having AUROC > 0.8 and PLS-SEM-SVM (AUROC = 0.978) perform superior than others. Thus, hybrid SVM model can be best utilized for flood susceptibility. This study provides the importance of mechanism for flood influencing factors and extends the application of proposed hybrid ML models to minimize flood risk. [ABSTRACT FROM AUTHOR]

In the decades leading up to the Civil War, American officials established multiple reservations on the west bank of the Missouri River and used it to delimit land for Indian Removal. They expected the wide Missouri to contain Indigenous peoples in the Great Plains to the west of the river, dividing them from white settlers on the east bank. Yet throughout this period, Siouan-speaking peoples in the central Plains—Omaha, Otoe, and Missouria peoples—fought to uphold their navigation rights on the river and preserve access to homelands on its east side. Enlisting Indigenous navigational technologies, they continued traveling on the river and landed repeatedly on its east bank, where they carried out hunting expeditions along eastern tributaries into northwest Missouri and western Iowa and confronted soldiers and settlers attempting to enforce the river boundary of Indian Territory. In doing so, Omahas, Otoes, and Missourias sustained their own deep histories of mobility and communication on Indigenous waterways that spanned American boundaries in the Great Plains. This article addresses how they resisted American authority across the Missouri watershed in the early to mid-nineteenth century. [ABSTRACT FROM AUTHOR]

Food availability and utilization are among the most critical factors influencing the distribution of free-ranging animals. Little is known about the feeding habit of the tiger (Panther tigris) outside the tiger reserves. We collected data on food habits of tigers in Dabka Watershed Area (DWA) of Kumaon Himalaya, Uttarakhand, India. Scats analysis was used to determine the food habit of the tiger. A total of 55 scats were collected and analyzed. The overall diet diversity of tigers in DWA (Shannon-Wiener Index H') was 2.923. Scat contents were analyzed in terms of both the relative frequency of occurrence and the relative prey biomass consumed. A minimum of 13 different prey species were identified, of which chital constituted 30.91% of the diet followed by sambar (21.82%). The wild prey constituted 77.36% of the diet, whereas domestic prey constituted 23.64% of the diet. Prey selectivity analysis indicated that selective predation by tigers was directed towards prey species with large body mass. This highlights the importance of adjacent forests around protected areas that helps large carnivores to disperse spatially and temporally during resource crunch, competition, and dispersal. [ABSTRACT FROM AUTHOR]

• New segmentation deals with intensity inhomogeneity within biological images. • Use of continuous formulation of B-spline level set with RSF active contour model. • Use of Watershed algorithm with a relevant choice of object markers. • The efficiency is proved in terms of qualitative and quantitative evaluation. Image segmentation plays an important role in the analysis and understanding of the cellular process. However, this task becomes difficult when there is intensity inhomogeneity between regions, and it is more challenging in the presence of the noise and clustered cells. The goal of the paper is propose an image segmentation framework that tackles the above cited problems. A new method composed of two steps is proposed: First, segment the image using B-spline level set with Region-Scalable Fitting (RSF) active contour model, second apply the Watershed algorithm based on new object markers to refine the segmentation and separate clustered cells. The major contributions of the paper are: 1) Use of a continuous formulation of the level set in the B-spline basis, 2) Develop the energy function and its derivative by introducing the RSF model to deal with intensity inhomogeneity, 3) For the Watershed, propose a relevant choice of markers that considers the cell properties. Experimental results are performed on widely used synthetic images, in addition to simulated and real biological images, without and with additive noise. They attest the high quality of segmentation of the proposed method in terms of quantitative and qualitative evaluation. The proposed method is able to tackle many difficulties at the same time: overlapped intensities, noise, different cell sizes and clustered cells. It provides an efficient tool for image segmentation especially biological ones. [ABSTRACT FROM AUTHOR]

Microfibers are small (<5 mm) fibers made of synthetic materials that are ubiquitous in the environment. The purpose of this observational study was to quantify the number of microfibers in marine sediments and determine which locations have the highest risk for this type of pollution. Sediment samples were taken from three locations in Southern California (Sycamore Watershed, Ventura State Beach Jetty, and Newport Beach Harbor) to determine which had the highest number of microfibers. It was hypothesized that microfibers would be found at each sample site and that the most microfibers would be found at Sycamore Watershed due to its proximity to a wastewater discharge point. The microfibers were separated from the sediment through a process of stratification and filtration and analyzed by a one-way ANOVA and Tukey s test. Per sample, there was an average of 111.5 (±99.3, n=14) microfibers found per sample at Sycamore Watershed, 59 (±17.4, n=18) at Newport Beach Harbor, and 53 (±14.4, n=18) at Ventura State Beach Jetty. A total of 3,590 microfibers were found from all three sample sites. Analysis revealed that Sycamore Watershed had significantly more microfibers than any other site (p<.05). It is likely that Sycamore Watershed had the most microfibers because of its proximity to a sewage-sludge disposal site that contains the polluted water from our washing machines. In conclusion, microfibers are polluting the sediments in harbors, open coastlines, and watersheds in California, negatively affecting the ecosystems in these areas. [ABSTRACT FROM AUTHOR]

One of the most important ways to improve quality and productivity in agriculture is to eliminate weeds, plant pathogens, and insects with pesticides. Although pesticides can effectively control agricultural quality and quantity, there are also lots of disadvantages due to their intensive usage resulting in degradation products. These products can accumulate in organisms and enter the food chain. Therefore, pesticides emanating from agricultural areas are agents that can affect the water quality of surface and groundwater sources. In this study, the presence of pesticides in the water and soil environment of the Borabey Pond and watershed which is situated north of Eskişehir, Turkey were determined by measurements. For this purpose, sediment and water samples from the pond and soil samples from the watershed were taken. The levels of organochlorine pesticides in the water, sediment and soil from Borabey Pond were determined between 0.5–13.8 ng/L, 0.03–1.02 μg/kg, and 0.54–52 μg/kg. Moreover, fugacity fraction has been measured that there is a transformation from water to sediment. Wilcoxon rank‐sum test is done to the seasonal measurements and there is no significant difference. Meanwhile, risk quotient (risk characterization ratio) estimates for DDTs and HCHs is below 1, so risk is acceptable. [ABSTRACT FROM AUTHOR]

Payment for Environmental Services (PES) is an effort and commitment of the world community in tackling the symptoms of global warming and damage to the ozone layer that will affect global climate change. Using field research methods, research data is collected through in-depth interviews with stakeholders in environmental services return programs in this research area. Research data is analyzed and described qualitatively for further conclusions. The concept developed upstream and downstream watershed relationships through the PES mechanism is based on the principle of voluntary agreement and awareness of maintaining the watershed ecosystem. The experience of implementing the PES Program in the Cidanau Watershed of Banten Province of Indonesia, managed by an independent institution. The PES program, in addition to its role as an environmental conservation program in the Cidanau watershed, also has socio-economical benefits for the community, environmental service (ES) users, and providers. [ABSTRACT FROM AUTHOR]

Brantas Watershed covers almost all regions of the Greater Malang (the Batu City, Malang City, and Malang Regency) and Blitar Regency in the East Java Province. These four cities/regencies are in one landscape so that several strategic sectors are interrelated. Global climate change impacts the form of environmental disasters in this region, which is even more significant in the future. This phenomenon has changed the development paradigm in this region. The research conducted descriptive analysis and observation in these four administrative areas to reveal the impacts on particular sectors, evaluate the preparedness of the four local governments, and formulate the strategies to integrate the development agendas in the landscape of Upstream Brantas Watershed. The study found that vulnerability and risk studies need to be carried out in an integrated perspective, then the local governments need to strengthen their adaptive capacity and include this agenda in the development programs. Likewise, the resolution of the problem needs to be done together across administrative boundaries, which is often a different challenge in Indonesia's administrative form of decentralization. [ABSTRACT FROM AUTHOR]

Managing water resources requires consideration of both environmental and socio-economic benefits to effectively balance the benefits and costs. This includes identifying ecosystem services (ES) of concern and how to evaluate the project or proposed changes effect on these ES. The purpose of this effort is to describe methods to evaluate ecosystem services to provide expanded irrigation to existing agricultural lands in Alabama and the potential application to other areas. A case study has been undertaken on the Middle Alabama watershed in central Alabama and methods have been developed and applied to evaluate ES in terms of how irrigated versus rainfed fields will affect sediment retention, fertilizer usage and the effect of the subsequent discharges of sediment and nitrogen from fertilizer on water quality. The results of case studies in the Middle Alabama watershed indicate positive ES benefits from sustainable agricultural practices and the irrigation of agricultural lands versus rainfed fields. We anticipate these methods will be applicable to other watersheds outside the southeast region too. [ABSTRACT FROM AUTHOR]

Benthic macroinvertebrates are widely used to assess the ecological quality of fresh waters. This is because they are in direct contact with the aquatic environment and respond differently to pollutants and changes in the watershed, which are difficult to assess by toxicological or chemical monitoring alone. This study used benthic macroinvertebrate parameters to assess the quality of the nearshore waters of lake Kivu. Twenty‐six metrics covering various aspects of the community were tested using whisker plots to compare their sensitivity in discriminating between reference and disturbed stations. Nine parameters (% EPT taxa, % Diptera taxa, % Chironomid taxa, % Insect taxa; % no Insects taxa, ratio EPT/Chironomid taxa, % moderate tolerant taxa, % very moderate tolerant taxa, Family Biotic Index) were found to be sensitive and were able to discriminate between reference and disturbed stations. All sensitive metrics, with the exception of the percentage of EPT taxa, were positively and/or negatively correlated with the physico‐chemical parameters affected by the changes in the littoral zone. The combined values of the three calculated biotic indices (ASPT, BMWP, and FBI) showed that the biological water quality varies from moderate to good in the reference stations and from average to poor in the disturbed stations. It is concluded that metrics based on benthic macroinvertebrates are effective for assessing water quality in the littoral zone of Lake Kivu in the context of the lack of historical water quality databases and specific tools for toxicological assessment. It is suggested to compare the performance of this approach with others currently used in bio‐indication. [ABSTRACT FROM AUTHOR]

Background: Snail control is critical to schistosomiasis control efforts in China. However, re-emergence of Oncomelania hupensis is challenging the achievements of schistosomiasis control. The present study aimed to test whether the amphibious snails can spread across watersheds using a combination of population genetics and geographic statistics. Methods: The digital maps and attributes of snail habitats were obtained from the national survey on O. hupensis. Snail sampling was performed in 45 counties of Sichuan Province. The cox1 gene of specimens was characterized by sequencing. Unique haplotypes were found for phylogenetic inference and mapped in a geographical information system (GIS). Barriers of gene flow were identified by Monmonier's maximum difference algorithm. The watercourses and watersheds in the study area were determined based on a digital elevation model (DEM). Plain areas were defined by a threshold of slope. The slope of snail habitats was characterized and the nearest distance to watercourses was calculated using a GIS platform. Spatial dynamics of high-density distributions were observed by density analysis of snail habitats. Results: A total of 422 cox1 sequences of O. hupensis specimens from 45 sampling sites were obtained and collapsed into 128 unique haplotypes or 10 clades. Higher haplotype diversity in the north of the study area was observed. Four barriers to gene flow, leading to five sub-regions, were found across the study area. Four sub-regions ran across major watersheds, while high-density distributions were confined within watersheds. The result indicated that snails were able to disperse across low-density areas. A total of 63.48% habitats or 43.29% accumulated infested areas were distributed in the plain areas where the overall slope was < 0.94°. Approximately 90% of snail habitats were closer to smaller watercourses. Historically, high-density areas were mainly located in the plains, but now more were distributed in hilly region. Conclusions: Our study showed the cross-watershed distribution of Oncomelania snails at a large scale. Natural cross-watershed spread in plains and long-distance dispersal by humans and animals might be the main driver of the observed patterns. We recommend cross-watershed joint control strategies for snail and schistosomiasis control. [ABSTRACT FROM AUTHOR]

Excessive inputs of nitrogen from anthropogenic activities in watersheds can cause detrimental effects to aquatic ecosystems, but these effects can be difficult to determine based solely on nitrogen concentrations because of their temporal variability and the need to link human activities to ecological responses. Here, we (1) tested the use of stable isotopes of nitrogen (δ15N) and carbon (δ13C) in benthic organic matter (BOM) as proxies for isotope ratios of filter feeding bivalves in lakes and estuaries, which can be used as indicators but are harder to sample and often spatially sparse, and (2) evaluated if stable isotope ratios in benthic organic matter could be used to assess impacts from anthropogenic land development of watersheds. The δ15N in BOM isolated from surficial sediment (δ15NBOM) was significantly correlated with δ15N in filter feeding unionid mussels (Elliptio complanata, δ15NUN) from lakes and with hard-shell clams (Mercenaria mercenaria, δ15NMM) from estuaries. In lakes, δ13CBOM was significantly correlated with δ13CUN, but δ13CBOM was not significantly correlated with δ13CMM in estuaries. Values of δ15NBOM and δ15NUN were significantly and positively correlated with increasing amounts of impervious surface, urban land cover, and human populations in watersheds surrounding lakes. In estuaries, δ15NBOM was only significantly and positively correlated with greater percent impervious surface in the watersheds. Correlations of δ13CBOM in lakes and estuaries, δ13CUN, and δ13CMM with land use and human population were mostly non-significant or weak. Overall, these results show that δ15NBOM can serve as a proxy for δ15N of filter feeding bivalves in lakes and estuaries and is useful for assessing anthropogenic impacts on aquatic systems and resources. Our study area was limited in size, but our results support further studies to test the application of this sediment stable isotope-based technique for assessing and ranking aquatic resources across broad geographical areas. [ABSTRACT FROM AUTHOR]

Sidi Mohamed Ben Abdellah dam watershed is one of the most vulnerable areas of the risk of soil degradation due to its wide exposure, lithological heterogeneity and varying climatic factors. In this sense, the qualitative study of the spatial-temporal evaluation of ground-level occupancy from satellite visualisation data (acquired by the Landsat TM 5 and Landsat TM 8) device derives a land-use map that shows the areas at risk of degradation after the integration of a combination of multiple factors into a GIS geographic information system (climate, terrain, pedology, vegetation cover and human intervention (anti-erosive practice); The results require adaptive vision to better control the phenomenon, to reduce its severity in areas at high risk of soil degradation. [ABSTRACT FROM AUTHOR]

Coastal ecosystems in Alaska are undergoing rapid change due to warming and glacier recession. We used a natural gradient of glacierized to non-glacierized watersheds (0–60% glacier coverage) in two regions along the Gulf of Alaska—Kachemak Bay and Lynn Canal—to evaluate relationships between local environmental conditions and estuarine fish communities. Multivariate analyses of fish community data collected from five sites per region in 2019 showed that region accounted for the most variation in community composition, suggesting that local effects of watershed type were masked by regional-scale variables. Seasonal shifts in community composition were driven largely by the influx of juvenile Pacific salmon (Oncorhynchus spp.) in late spring. Spatiotemporal differences among fish communities were partly explained by salinity and temperature, which accounted for 19.5% of the variation in community composition. We used a multi-year dataset from Lynn Canal (2014–2019) to examine patterns of mean length for two dominant species. Generalized additive mixed models indicated that Pacific staghorn sculpin (Leptocottus armatus) mean length varied along site-specific seasonal gradients, increasing gradually through the summer in the least glacially influenced sites and increasing rapidly to an asymptote of ~ 150 mm in the most glacially influenced sites. Starry flounder (Platichthys stellatus) mean length was more strongly related to environmental conditions, increasing with temperature and turbidity. Together, our findings suggest that community compositions of estuarine fishes show greater variation at the regional scale than the watershed scale, but species-specific variation in size distributions may indicate differences in habitat quality across watershed types within regions. [ABSTRACT FROM AUTHOR]

The Great Wall is a world-famous World Heritage Site facing serious environmental and structural fragmentation problems. This study considered the watershed an essential basis for delineating the Great Wall cultural zone boundary. The relevant watersheds and their scope in the Beijing Great Wall cultural zone were determined, and a sub-watershed classification index system was constructed. The sub-watershed type conservation areas were classified using the k-means clustering method. The relationships among heritage, ecological, socioeconomic, and hydrological elements were analyzed to obtain the essential characteristics of the spatial differentiation of watershed types. Heritage had a promoting effect on urbanization; urbanization had a pressurizing effect on the ecological environment, whereas heritage had a binding effect on the ecological environment. The protected areas defined at the sub-watershed scale in this study have better connectivity and integrity. Not only does it help to monitor, prevent and control the various natural and human-related issues and hazards that occur at the watershed scale, but it also helps in informing the sustainable conservation and development of the Great Wall. [ABSTRACT FROM AUTHOR]

A rare dataset of in‐situ10Be from high‐resolution depth profiles, soils, rock outcrops, and stream sediments is combined with geochemical analysis and modelling of regolith evolution to understand the variability of denudation rates in a mountain watershed (Strengbach critical zone observatory). High‐resolution depth profiles are key to detect the presence of mobile regolith and to highlight how it affects the critical zone evolution. The modelling of regolith evolution and 10Be concentrations along depth profiles allow us to estimate both the cosmic ray exposure age (19 kyr) and the mean denudation rate (22 mm kyr−1) of the regolith without any steady‐state assumption on 10Be concentrations. Comparison with maximum denudation rates inferred from topsoil samples collected from the surface of the depth profiles and calculated using the temporal steady‐state assumption of 10Be concentrations highlights an overestimation of denudation by a factor of two. Maximum spatially averaged denudation rates determined from stream sediment samples also likely overestimate denudation rates by a factor of two. These biases are significant for investigating the geomorphological evolution and we propose a method to correct denudation rates using the inherited 10Be concentrations and the cosmic ray exposure age deduced from the high‐resolution depth profiles. A key result is also that a steady state of 10Be concentrations and a steady state of regolith thickness are two different equilibrium states that do not necessarily coincide. The comparison between locally corrected and spatially averaged denudation rates indicates that the watershed geomorphology is not in a topographic steady state but is modulated by regressive fluvial erosion. Nonetheless, our study demonstrates that even in a watershed where the steady‐state assumption of 10Be concentrations is not verified, the spatial variations of in‐situ10Be concentrations in sediments still carry qualitatively relevant information on the geomorphological evolution of landscapes. [ABSTRACT FROM AUTHOR]

Although collective action is needed to address many environmental challenges, it cannot proceed in the absence of collective identity, that is, evidence of group belongingness expressed in or via communicative behavior. This study looked for evidence of a collective identity in newspaper articles that referenced the Chesapeake Bay Watershed. The data were drawn from local papers published in municipalities located at the headwaters of the Susquehanna River, midway down the Susquehanna, and where the river meets the Bay. Computerized content analysis assessed the frequency with which the Chesapeake Bay and watershed were mentioned alongside a set of keywords thought to represent different facets of identity (e.g., agriculture, fishing, swimming). The results showed substantial variation in frequency across time and place but low absolute levels of coverage of the Bay and the watershed. Multidimensional scaling revealed different structures to collective identity as a function of place. These differences in content may be attributable to varying demographic and environmental characteristics along with proximity to the Bay. But, to the extent that media contribute to collective identity among residents of the watershed at all, they do so in a complex and heterogeneous manner. [ABSTRACT FROM AUTHOR]

Freedom came to India along with violence. The joy of independence was overshadowed by the painful partition of the great land along religious lines as India and Pakistan. In the process, thousands were slaughtered, a great number of women were raped, abducted and mutilated and millions were rendered homeless. Thus, the Partition of India remains a painful, watershed moment in the Indian freedom struggle. The events which led to the partition, the partition itself and its aftermath have captured the imagination of quite a few creative writers. These writers have given faithful and artistic accounts of the partition of the great land of India in their creative works. This has given birth to the genre of 'The Partition Novel.' The present article is a critical study of Manohar Malgonkar's A Bend in the Ganges, based on the Partition theme. [ABSTRACT FROM AUTHOR]

The present study aimed to analyze the spatial–temporal variation of water streams using Quality Indexes of the Minas Gerais Institute of Water Management (WQI-IGAM), compared with physical–chemical and biological variables established by the CONAMA Resolution 357/2005 employed for water classification. A water stream in the city of Cachoeira-Alta, State of Goiás, Brazil was used as a case study. Four sampling points along the water course were planned; at each point, the variables of dissolved oxygen (DO), temperature (T) and hydrogen potential (pH) were analyzed, using portable equipment, and samples were collected for laboratory analyses of the variables total phosphorus (TP), biochemical oxygen demand (BOD), total nitrogen (TN), turbidity (Turb), total residues (TR) and thermotolerant coliforms (TC). The waters were classified as of poor quality in relation to the variables TP and TC. The water course was classified as class 3 for the results of TP, class 2 for the results of BOD and TC and class 1 for the results of the other variables, according to CONAMA Resolution 357/2005. It is expected that the watershed management bodies will have a greater concern in the supervision of these resources, requiring greater protection of riparian forests and adequate management of watersheds. [ABSTRACT FROM AUTHOR]

The Cikapundung Watershed is part of the Citarum watershed, which functions as the main drainage of the center of Bandung City. High exploitation of space and water resources can trigger flooding, as is often the case in the Cikapundung watershed. Flooding can be caused by rapid population growth, land degradation, and climate change. In this study, four types of methods were used to analyze rainfall frequency, and the type III Log Pearson distribution method was found to meet the requirements for use. A match test was carried out using the chi-squared method and the Smirnov-Kolmogorov method. Hydraulics analysis was carried out by the HEC-RAS method with different return periods to calculate the depth of flooding. HEC-RAS was used because it is considered highly compatible and relevant to geatographic information systems. The return periods modeled with HEC-RAS were 2, 5, 10, 25, 50, and 100 years. Based on the calculation results, the Cikapundung watershed runoff coefficient in 2020 was.43. The increased return period suggests that the area of flood inundation is becoming wider. The downstream impacts of wider flood inundation include all sectors that are more affected by flooding. This causes losses to increase as the flood payback period increases. The total estimated loss for the 25 return periods of flood events in the Cikapundung watershed is around 1,124 million rupiah, and the affected population is around 700,000 people. [ABSTRACT FROM AUTHOR]

Remote sensing and GIS technology were very helpful to determine an appropriate location of freshwater storage in Amhara, Ethiopia. The techniques were used to investigate the impact of lithology, surface geomorphology, slope parameters, drainage flow, drainage density, lineament density, land cover parameters on relief, and aerial and linear features and to understand their interrelationships. Morphometric parameters such as mean stream length (Lsm), stream length ratio (RL), bifurcation ratio (Rb), mean bifurcation ratio (Rbm), relief ratio (Rh), drainage density (Dd), stream frequency (Fs), drainage texture (Rt), form factor (Rf), circularity ratio (Rc), and elongation ratio (Re) were calculated. Spatial maps of morphometric parameters were produced by using AHP (analytical hierarchy process) of ArcGIS 10.3. Final priority map was generated by the overlay of those parameters with five categories of poor (16.6%), low (41.63%), moderate (29.61%), high (8.88%), and very high (3.28%) storage locations. The map showed that this study area belonged to the low to moderate storage location. The results exhibit precision-based assessment of the suitability for the dam construction sites of 6, 7, and 9 sub-basin zones. The outcome of this study strengthens the knowledge of geospatial analysis for water resources vulnerability and also allows policymakers in this drought-prone area to sustainably manage water supplies. [ABSTRACT FROM AUTHOR]

Water availability in lakes must be studied in order to better manage ecosystems within lake basins and meet economic development needs. Despite being Iran's largest lake, Lake Urmia's water level and surface area have declined dramatically over the past two decades. During the same period, Lake Van in Turkey maintained a relatively stable water level and surface area. As a result, comparing factors related to water level and surface area in these lakes, which have similar geographical and climate conditions but different management policies, can be an appropriate way to identify the causes of water declines in Lake Urmia. Comparing these variables may help explain observed differences in lake behavior between 2000 and 2016. Hydrometric and climatic parameters, as well as the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Water Index (NDWI), were used to achieve this goal. Changes in precipitation, temperature, and evapotranspiration in both lakes show essentially identical trends, but this is not a convincing explanation for Lake Urmia's water surface changes. The results revealed that dam construction and water diversion projects, the expansion of irrigated agriculture, and the lake's shallow depth in most parts were the primary causes of Lake Urmia's shrinkage compared to Lake Van. [ABSTRACT FROM AUTHOR]

Riparian vegetation on river borders can affect the riparian ecosystem of the watershed related to its function as a buffer zone and ecotone between water and land. A high diversity of riparian vegetation can indicate that the ecosystem of a river border is in good condition. Therefore, it is helpful to inventory the diversity of vegetation in the riparian zone, which was done in this study using the Shannon-Wiener diversity index. In this research, four plots measuring 5m x 5m, spread across upstream, middle, and downstream areas were used to analyze the types of vegetation, including trees, shrubs, and herbs. The diversity index (H') results revealed four vegetation species at the tree level, twelve species at the shrub level, and six species at the herb level. The range of H' values in all sample plots was 1< H' <3, so the river border was shown to have moderate diversity, which indicated that the ecosystem in the Sampean watershed is relatively balanced. It is necessary to preserve the riparian buffer zone through riparian vegetation restoration management to improve the ecosystem balance of the Sampean watershed. [ABSTRACT FROM AUTHOR]