Impact Assessment of Land-Use Changes on Nutrient Load in Song Cau Watershed Using Soil and Water Assessment Tool （SWAT） Model

The objective of this paper is to implement ＂Soil and Water Assessment Tool （SWAT）＂ model to assess the possible impact of land-use changes on nutrient yields from Song Cau watershed located in Northern Viet Nam. Organic nitrogen （N） as well as phosphorus （P） output due to nonpoint source erosion was estimated through SWAT. Parameters governing the mechanics of streamflow discharge, sediment yield, nitrogen, and phosphorus output in SWAT were calibrated in a distributed fashion. A five-year period of record for nutrient was used for model calibration, while a four-year period was used for model validation. Comparing measured versus simulated average monthly total N, and P loads for the calibration and validation periods; respectively, we found that SWAT model performed reasonably well for Song Cau watershed. Simulation results showed that monthly Nash-Sutcliffe coefficient of Efficiency （NSE） ranged from 0.65 to 0.83, observation＇s standard deviation ratio （RSR） and percent bias （PBIAS） ranged from 0.41 to 0.58 and -36.12 to 2.78, respectively. Additionally, SWAT simulation results also showed that land-use changes caused significant percentage of changes in sediment yield, total N, and P loads within Song Cau watershed.

Long Term Soil and Water Assessment Tool (SWAT) Calibration from an Ecohydrology Perspective

The performance on prediction by mathematical models which represent the conceived image of a system such as hydrology is oftentimes represented through calibration and verification processes. Oftentimes a best fit between observed and predicted flows is obtained through correlation coefficient (R2) and the Nash Sutcliffe model efficiency (NSE) by minimizing the average Root Mean Square Error (RMSE) of the observed versus simulated flows. However, these days, a new paradigm is emerging wherein accounting for the flow variability for the protection of freshwater biodiversity and maintenance of goods and services that rivers provide is paramount. Therefore, from an ecohydrology perspective, it is not clear if the existing method of model calibration meets the needs of the riverine ecosystem at its best. Thus, this study investigates and proposes a methodology using entropy theory to gage the calibration of Soil and Water Assessment Tool (SWAT) from an ecohydrology perspective characterized by the natural flow-regime paradigm: Indicators of Hydrologic Alteration.

Assessment of groundwater suitability for different activities in Toshka district,south Egypt

Globally,groundwater has globally emerged as a crucial freshwater source for domestic,irrigation,and industrial needs.The evaluation of groundwater quality in the Toshka region is imperative to ensure its suitability for the extensive agricultural and industrial activities underway in this promising,groundwater-dependent development area.This is particularly significant as Egypt increasingly relies on groundwater reserves to address freshwater deficits and to implement mega-development projects in barren lands.In this study,fifty-two samples were collected from the recently drilled wells tapping into the Nubian Sandstone Aquifer(NSA)in the Toshka region.Groundwater quality was assessed through hydrochemical analysis,Piper diagram,and various indicators such as Na%,SAR,RSC,KR,MH and PI.The hydrochemical analysis revealed improved groundwater quality characteristics,attributed to continuous recharge from Lake Nasser.The Piper diagram categorised most of the water samples as"secondary salinity"water type.Almost all wells proved suitable for irrigation with only two wells unsuitable based on MH values and six wells based on KR values.Considering Total Hardness(TH)values,all samples were classified as"Soft",indicating their suitability for domestic and industrial purposes.Water Quality Index(WQI)results concluded that all samples met WHO and FAO guidelines for drinking and irrigation,respectively.Spatial distribution maps,constructed using GIS,facilitate the interpretation of the results.Regular monitoring of quality parameters is essential to detect any deviation from permissible limits.

Assessment of Water Quality in High-Pressure Peruvian Anthropic Sectors of Lake Titicaca Using a Calibrated Index

The world’s lakes are in the process of degradation, with loss of water quality as a result of anthropic influences. This research aimed to evaluate water quality in high-pressure Peruvian anthropic sectors of Lake Titicaca using a calibrated index. The study considered ten important bays with influence from urban sectors. In each bay, surface waters were monitored for six years, considering physical, chemical and microbiological parameters. Water quality was assessed using the NSF Water Quality Index (NSF-WQI) and the one calibrated for Lake Titicaca (WQIT). Comparing the efficiency of these two indices, the WQIT showed a variation from moderately polluted bays to bad quality bays, such as Desaguadero and Yunguyo. These two bays were classified as hypereutrophic, therefore, the uses attributable to this condition are only irrigation and energy production. Applying the NSF-WQI, the results were not able to identify this significative difference, as all bays were classified as moderate quality waters. This result indicates that the WQIT calibration was adequate, as it allows inferring and estimating the water quality of Lake Titicaca with greater precision. According to Peru’s water quality standard for category 4, established for the conservation of the country’s lakes, the parameters that exceeded the standard values were PO4-P (0.035 mg∙L−1) and BOD5 (5 mg∙L−1) in all bays, and TC (1000 MPN mL−1) in Yunguyo bay. These high values indicate eutrophication processes, one of the main problems in the study area. The WQIT calibrated for Lake Titicaca can be used as an efficient tool to assess water quality in high Andean lentic waterbodies in South America.

Assessing the Impact of Petrol Service Stations on Selected Physico-Chemical Water Quality Parameters within Port Harcourt Metropolis, Nigeria

This study assessed the impact of petrol service stations on physico-chemical water quality in Port Harcourt metropolis, Rivers State. This threw light on the extent of damage and alteration of water quality in Port Harcourt metropolis as a result of the proliferation of petrol service stations especially the condition of ground and nearby surface water. This serves as a useful tool to government and regulatory authorities for planning especially due to lack of central water supply system in Port Harcourt metropolis. The parameters studied were sampled, measured and analyzed using in situ and other standard methods. Remarkable results above permissible limits of interest for physicochemical parameter analysis revealed pH values from 4.6 to 6.8, electrical conductivity from 0.002 µS/cm to 0.42 µS/cm, salinity from 3 ppm to 4050 ppm, and temperatures from 19.9˚C to 32.6˚C. Total dissolved solids (TDS) varied from 7 ppm to 1000 ppm, biochemical oxygen demand (BOD) from 0.167 mg/L to 2.167 mg/L, chemical oxygen demand (COD) from 0.257 mg/L to 3.253 mg/L, and dissolved oxygen (DO) concentrations from 1.70 mg/L to 4.30 mg/L. Specifically, water samples from NNPC Filling Station (Choba) and Eneka Pond displayed “Poor” water quality with WQI values of 112.003 and 112.076, respectively. Similarly, ALLTEC Filling Station (Eneka) and TOTAL Filling Station (Rumuomasi) had “Poor” water quality with WQI values of 173.707 and 180.946, respectively. In contrast, Excelsis Filling Station (Akpajo) demonstrated “Good” water quality with a WQI of 85.2072, while Total Filling Stations (Slaughter) and Choba River revealed “unsuitable for drinking” water quality with WQI values of 552.461 and 654.601, respectively. Slaughter River also indicated very poor water quality with a WQI of 442.024. The physicochemical and nutrient analyses of the water samples showed that activities of the filling stations within the study area may have polluted groundwater in the environment posing poor aesthetics and great health risk to consumers of the water bodies. The findings underscore the need for immediate remediation efforts and stricter regulatory measures to protect water quality. The study concluded that surface and groundwater near petrol service stations in Port Harcourt are unfit for drinking and irrigation purposes without adequate treatment.

Consistency of Tropospheric Water Vapor between Reanalyses and Himawari-8/AHI Measurements over East Asia

High spatiotemporal resolution radiances from the advanced imagers onboard the new generation of geostationary weather satellites provide a unique opportunity to evaluate the abilities of various reanalysis datasets to depict multilayer tropospheric water vapor(WV),thereby enhancing our understanding of the deficiencies of WV in reanalysis datasets.Based on daily measurements from the Advanced Himawari Imager(AHI)onboard the Himawari-8 satellite in 2016,the bias features of multilayer WV from six reanalysis datasets over East Asia are thoroughly evaluated.The assessments show that wet biases exist in the upper troposphere in all six reanalysis datasets;in particular,these biases are much larger in summer.Overall,we find better depictions of WV in the middle troposphere than in the upper troposphere.The accuracy of WV in the ERA5 dataset is the highest,in terms of the bias magnitude,dispersion,and pattern similarity.The characteristics of the WV bias over the Tibetan Plateau are significantly different from those over other parts of East Asia.In addition,the reanalysis datasets all capture the shift of the subtropical high very well,with ERA5 performing better overall.

Lead, Zinc and Iron Pollutants Load Assessment in Selected Rivers in Southern Nigeria: Implications for Domestic Uses

The aim of the study is to comparatively assess the concentrations of lead, zinc and iron in Rivers Ase, Warri and Ethiope, in Nigeria. Monthly water samples were collected from six randomly selected sites along the rivers course. 72 water samples were collected from each river at 0 - 15 cm depths. Samples were analysed based on the standard methods recommended by the WHO for testing lead, zinc and iron. The assessment of the water quality was done using the Water Quality Index (WQI) of the Canadian Council of Ministers of the Environment (CCME-WQI). While hypotheses were tested using ANOVA. Findings indicated that CCME-WQI values were 47.3, 66.52 and 78.7. This meant that the water quality of River Ase is impaired and departed from desirable levels, while that of Warri and Ethiope were considered to occasionally be impaired and depart from desirable levels. The ANOVA model showed that there is a significant variation in heavy metal load in the selected rivers at P < 0.05. River water was put to domestic uses such as drinking (20.5%) preparing food (17.8%), bathing (19.8%), washing clothes and dishes (21.3%), brushing teeth (13.3%), and catering for domestic animals (7.5%). Poverty (49.5%) was the major reason for the use of river water for domestic purposes. The locals highlighted that they usually suffer from cholera (26.8%), diarrhoea (25.8%), dysentery (24%) and typhoid (23.5%) as a result of using the river water. The study recommended routine monitoring of anthropogenic and geologic activities, testing of the water regularly amongst others.

Sustainable Water Management Through Pani Panchayats: Stakeholder Perspectives from Angul and Dhenkanal Districts of Odisha

This study evaluates the impact of the Pani Panchayat initiative, a community-based water management program, in the Angul and Dhenkanal districts of Odisha. Utilizing a mixed-methods approach, we gathered qualitative and quantitative data through structured interviews with diverse stakeholders, focus group discussions, and surveys. The findings indicate that the Angul district exhibited higher levels of fair elections and improved water access due to better canal maintenance, while the Dhenkanal district faced challenges from industrial water usage. The study also examines the potential of technological advancements, such as real-time water monitoring, to enhance governance. By identifying synergies and gaps with existing water policies, the research provides policy recommendations to promote sustainable water management in alignment with the Sustainable Development Goals 2030.

Defining Soil and Water Assessment Tool(SWAT)hydrologic responseunits(HRUs)by field boundaries

The Soil and Water Assessment Tool(SWAT)is widely used to relate farm management practices to their impacts on surface waters at the watershed scale,yet its smallest spatial unit is not generally defined by physically meaningful boundaries.The hydrologic response unit(HRU)is the smallest spatial unit of the model,and the standard HRU definition approach lumps all similar land uses,soils,and slopes within a subbasin based upon user-defined thresholds.This standard method provides an efficient way to discretize large watersheds where simulation at the field scale may not be computationally feasible.In relatively smaller watersheds,however,defining HRUs to specific spatial locations bounded by property lines or field borders would often be advantageous,yet this is not currently possible within the ArcSWAT interface.In this study,a simple approach is demonstrated that defines HRUs by field boundaries through addition of uniquely named soils to the SWAT user soil database and creation of a field boundary layer with majority land use and soil attributes.Predictions of nitrogen,phosphorus,and sediment losses were compared in a case study watershed where SWAT was set up using both the standard HRU definition and field boundary approach.Watershed-scale results were reasonable and similar for both methods,but aggregating fields by majority soil type masked extremely high soil erosion predicted for a few soils.Results from field-based HRU delineation may be quite different from the standard approach due to choosing a majority soil type in each farm field.This approach is flexible such that any land use and soil data prepared for SWAT can be used and any shapefile boundary can divide HRUs.

Assessment of Domestic Water Sources Safety: Application of the Micro Biological Survey Method and Microbiological Profile of the Contaminating Bacteria

Water is essential for human life and it’s expected to be clean and safe. In Cameroon, government efforts to improve access to drinking water are mitigated. Many households are suffering from chronic water shortages leading to the majority of people using doubtful water sources. This study was carried out in accordance with guidelines produced by the STARBIOS2-EU funded project on Responsible Research and Innovation and aimed to assess the microbiological quality of water samples collected from domestic water sources in 3 divisions of the West region of Cameroon. 22 water samples from well water, stream, water pump and river were aseptically collected. At each sampling point, 50 mL of sample was taken aseptically and immediately transported to the laboratory for analysis. The detection of Coliforms bacteria was done using Micro Biological Survey (MBS) method. 1 mL of each sample was inoculated in the Coliforms MBS (Coli MBS) vial initially rehydrated with 10 mL of sterile distilled water. The Coli MBS vials were closed, shaken for homogenization, and then incubated at 37°C. From the initial red color of the Coli MBS vials, changes in color to yellow of the reaction vials were monitored at three different time intervals (12 h, 19 h and 24 h), corresponding to three levels of bacterial concentration. All positives samples on MBS method were selected to determine the presence of E. coli Loop full broths of Coli MBS vials were taken;streaked into the eosin methylene blue (EMB) agar plate and incubated at 37°C for 24 hours. E. coli was confirmed by observing green metallic sheen on EMB agar plate. The biochemical indole, methyl red, Voges-Proskauer and citrate (IMViC) test was performed to determine the complete microbiological profile of the water samples. Almost all the water samples were contaminated with Total Coliforms (TC). A high concentration of TC (>103 CFU/mL) was found in 8 samples (36.4%), a medium concentration (10 < x < 103 CFU/mL) was observed in 10 samples (45.5%) and 2 samples (9.1%) were low concentrated (1 < x < 10 CFU/mL). 8 samples were positive for the presence of E. coli by observing the green metallic sheen on EMB agar plates. The IMViC test confirmed the presences of 5 bacteria species: Enterobacter spp., Klebsiella spp., E. coli spp., Salmonella spp. and Shigella spp. We recommend integrating sanitary assessment in the design and implementation of water supply projects. Regular water purification using proper methods and maintenances of the water point. Regular microbiological quality assessment of water intended for human consumption should be planned and carried out.

Projection pursuit cluster model and its application in water quality assessment

One of the difficulties frequently encountered in water quality assessment is that there are many factors and they cannot be assessed according to one factor, all the effect factors associated with water quality must be used. In order to overcome this issues the projection pursuit principle is introduced into water quality assessment, and projection pursuit cluster(PPC) model is developed in this study. The PPC model makes the transition from high dimension to one-dimension. In other words, based on the PPC model, multifactor problem can be converted to one factor problem. The application of PPC model can be divided into four parts: (1) to estimate projection index function Q(); (2) to find the right projection direction ; (3) to calculate projection characteristic value of the i th sample z-i, and (4) to draw comprehensive analysis on the basis of z-i. On the other hand, the empirical formula of cutoff radius R is developed, which is benefit for the model to be used in practice. Finally, a case study of water quality assessment is proposed in this paper. The results showed that the PPC model is reasonable, and it is more objective and less subjective in water quality assessment. It is a new method for multivariate problem comprehensive analysis.

Recommending the IHACRES model for water resources assessment and resolving water conflicts in Africa

The International Association of Hydrological Sciences （IAHS） recognized the lack of hydro- logical data as a world-wide problem in 2002 and adopted the Prediction of Ungauged Basins （PUB） as a decadal research agenda during the period of 2003 to 2012. One of the objectives is to further develop methodologies for prediction in ungauged basins and to reduce uncertainties in model prediction. Estimation of stream flows is required for flood control, water quality control, valley habitat assessment and water budget of a country. However, the majority of water catchments, streams and valleys are ungauged in most developing countries. The main objective of this paper is to introduce the IHACRES （Identification of Hy- drographs and Components from Rainfall, Evaporation and Stream） model into African hydrological plan- ning as a methodology for water resources assessment, which in turn can be used to resolve water conflicts between communities and countries and to study the climate change issues. This is because the IHACRES model is applied for the estimation of flows in ungauged catchments whose physical catchments descriptors （PCDs） can be determined by driving variables （i.e. rainfall and temperature）; and also in gauged streams but whose gauging stations are no longer operational but historical data are available for model calibration. The model provides a valuable insight into the hydrologic behaviour of the upper water sources for valleys as well as provides a useful methodology for water resources assessment in situations of scarce financial resources in developing countries. In addition, it requires relatively few parameters in its calibration and has been successful applied in previous regionalization studies. It will also make possible the equitable distri- bution of water resources in international basins and rivers＇ catchments. This paper does not apply the model anywhere, but recommends it as a methodology for water resources assessment in order to cure water conflicts on the African continent.

Surface water quality and potential health risk assessments in Changsha-Zhuzhou-Xiangtan section of Xiangjiang River, China

The Changsha-Xiangtan-Zhuzhou City Group is a heavy industrial district and accepted as the serious pollution area in the Xiangjiang River basin.In this study,7 metals(Pb,Hg,Cd,As,Zn,Cu and Se)and the river water quality parameters including pH,dissolved oxygen(DO),Escherichia coli(E.coli),potassium permanganate index(CODMn),dichromate oxidizability(CODCr),five-day biochemical oxygen demand(BOD5),ammonia nitrogen(NH4+-N),total nitrogen(TN),total phosphorus(TP)and fluoride(F)in 18 sampling sites of the Changsha-Xiangtan-Zhuzhou section are monthly monitored in 2016,which is the year to step into the second stage of the“Xiangjiang River Heavy Metal Pollution Control Implementation Plan”.It is found that E.coli,TN and TP are the main pollutants in the Changsha-Zhuzhou-Xiangtan section,and the pollution of heavy metal is not serious but As with potential risk to local people especially children should be concerned.In addition,Xiangtan city is mainly featured with heavy metal pollution,while Zhuzhou and Changsha city are both featured with other pollutants from municipal domestic sewage.

Assessment of Soil Water Content in Field with Antecedent Precipitation Index and Groundwater Depth in the Yangtze River Estuary

To better understand soil moisture dynamics in the Yangtze River Estuary （YRE） and predict its variation in a simple way, a field monitoring experiment was carried out along the north branch of the Yangtze River, where seawater intrusion was strong and salt-water variation is one of the limiting factors of local agriculture. In present paper, relation between antecedent precipitation index （API） and soil water content is studied, and effects of groundwater depth on soil water content was analyzed. A relatively accurate prediction result of soil water content was reached using a neural network model. The impact analysis result showed that the variation of the API was consistent with soil water content and it displayed significant correlations with soil water content in both 20 and 50 cm soil layer, and higher correlation was observed in the layer of 20 cm. Groundwater impact analysis suggested that soil moisture was affected by the depth of groundwater, and was affected more greatly by groundwater at depth of 50 cm than that at 20 cm layer. By introducing API, groundwater depth and temperature together, a BP artificial network model was established to predict soil water content and an acceptable agreement was achieved. The model can be used for supplementing monitoring data of soil water content and predicting soil water content in shallow groundwater areas, and can provide favorable support for the research of water and salt transport in estuary area.

Assessment of Drinking Water Quality in Umoja Innercore Estate, Nairobi

Water quality is one of the main indicators of the quality of service provided to consumers. Quality has an impact on both the public health and aesthetic value of water as a consumable product. Kenya is classified as a water-scarce country with only 647 cubic meters of renewable freshwater per capita. Water distributed in Nairobi is faced with a myriad of challenges leading to a compromise to its quality. This study focused on evaluating quality of drinking water since human health depends on adequate, clean, reliable water. Analyses were carried out at National Environmental Management Authority (NEMA) accredited Jomo Kenyatta University of Agriculture and Technology (JKUAT) laboratories to determine the chemical, bacteriological and physical characteristics of consumed water in Umoja Innercore Estate in Nairobi. In the study area, 7 HH and 6 BH sites were randomly distributed. pH, turbidity and temperature measurements were analyzed in-situ while bacteria and chemicals were analyzed in laboratories. The study found that 100% of boreholes recorded unsatisfactory water with up to 1100 of Escherichia coli (E. coli) showing high contamination with faecal coliforms and 83% of boreholes recording pH of up to 9.53. Dissolved oxygen was 5.08 mg/L below recommended 12.0 mg/L, salinity of 0.47 mg/L and 0.03 mg/L for boreholes and households respectively. The study reveals the deprived quality of water available to the residents of Umoja Innercore, Nairobi. The study recommends the use of biosand filtration methods for septic tanks, digging of deeper boreholes and lining septic tanks with impermeable materials to prevent contamination of ground water with raw water from septic.

Water Security-based Hydrological Regime Assessment Method for Lakes with Extreme Seasonal Water Level Fluctuations：A Case Study of Poyang Lake,China

Extreme seasonal water level fluctuations characterize natural floodplain lakes in monsoon regions, which are crucial for ensuring lake water security, including flood prevention water supply and health of aquatic ecosystem. In order to achieve this goal, we established a hydrological regime assessment method based on a set of hydrological indicators for lakes with heavy seasonal water level fluctuations. The results suggest that time-sensitive hydrological indicators and specific time scales for various water security aspects must be considered. We discovered that it is more practical and meaningful to combine the water level classification derived from statistical analyses with characteristic hydrological values linked to water security. The case study of Poyang Lake results show that there are no discernable trends of Poyang Lake water regime status over the last 35 years, and the two periods of poor status are in accordance with climate variation in the lake basin area. Scholars and policy makers should focus on both floods and droughts, which are the main water security problems for Poyang Lake. It is hoped that this multi-scale and multi-element hydrological regime assessment method will provide new guidelines and methods for other international scholars of river and lake water assessment.

Assessment on the pollution of nitrogen and phosphorus of Beijing surface water based on GIS system and multivariate statistical approaches

This paper presented the characteristics of nitrogen and phosphorus pollution in Beijing surface water during the survey. A significant difference was found out in concentration distribution of various parameters of nitrogen and phosphorus. Most water bodies in five water systems were polluted by total nitrogen with the content even up to 120 mg/L which was higher than exceeded the fifth class standard of national surface water quality standard GB3838-2002 except for several segments of Chaobaihe and Yongdinghe. Ammonia and phosphorus showed a similar tendency of distribution with higher content in Daqinghe, Beiyunhe and Jiyunhe water systems, but with relatively low concentrations in Chaobaihe and Yongdinghe water systems. Meanwhile, nitrate was found at comparatively low content(mostly less than 10 mg/L) and could fit for corresponding water quality requirements. Totally, the water quality of Daqinghe, Jiyunhe and Beiyunhe river systems as well as the lower reaches of Yongdinghe and Chaobaihe was contaminated seriously with high content of total nitrogen and phosphorus. Through multivariate statistical approaches, it can be concluded that total nitrogen, ammonia and total phosphorus was highly correlated to chemical oxygen demand, biochemical oxygen demand, dissolved oxygen and electrical conductivity, which explained the same pollution source from anthropogenic activities.

Assessment and utilization of soil water resources

Based on the analyses of water interactions and water balance, this paper discusses the issues on the assessment and regulation of soil water resources, which lays the scientific basis for limited irrigation and water-saving agriculture.

Fuzzy Complex Index in Water Quality Assessment of Municipalities

Donghu Lake in Wuhan is a multipurpose complex water body. However, its eutrophication phenomenon becomes increasingly serious. By making use of detailed and accurate contamination monitoring data and several mathematics models, we probe into the dynamic state of water quality. The year’s average value of major contamination index in Donghu Lake from 2001 to 2008 and fuzzy complex index are used to assess its short-term state of water quality. The results show that its water quality is basically stable in the 4th class of water quality standard GB3838-2002.

Ecological service assessment of human-dominated freshwater ecosystem with a case study in Yangzhou Prefecture, China

Freshwater ecosystems provide a host of services to humanity. These services are now rapidly being lost, not least because of the inability of making the impacts measurable. To overcome this obstacle, assessment frameworks for freshwater ecosystem services are needed. A simple water equivalent framework to assess the ecological services provided by freshwater ecosystems was developed in this study. It translated the occupation of freshwater ecosystem services into biologically freshwater volumes and then compares this consumption to the freshwater throughput, that is, the ecological capacity available in this region. In this way, we use the example of Yangzhou Prefecture, to account the main categories of human occupation of water ecosystem services. The result showed that there is a huge gap between the consumption and the supply of freshwater ecosystem services. This must encourage local government to make land-use and water management decisions both economically rational and environmentally sound.