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Assessing Water Quality by Statistical Methods
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Assessing Water Quality by Statistical Methods

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Water Quality and Contamination".

Deadline for manuscript submissions: closed (15 December 2020) | Viewed by 51703

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editor

Prof. Dr. Alina Barbulescu

E-Mail Website
Guest Editor
Department of Civil Engineering, Transilvania University of Brașov, Brașov 500036, Romania
Interests: hydrology; applied statistics; mathematical modelling; time series analysis; water quality assessment
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Society's progress has resulted in increasing the quantity of pollutants emitted in the environment. Water is one of the natural resources most affected by economic activity, with pollutants reaching water bodies without proper treatment. Climate change impacts the water quality as well. Water pollution damages organisms living in the water and many ecosystems. In a world where over 4 billion people suffer from water scarcity, preserving the water resources, assessing the water quality, and remediation are essential.

This Special Issue will feature the latest advances and developments in statistical approaches for evaluation and forecasting of water resources quality. The development of new methodologies and improving the known methods are especially welcome.

The main topics of this  Special Issue include but are not limited to:

  • Water quality indicators
  • Parametric and nonparametric approaches for assessing the groundwater vulnerability
  • Spatial distribution and uncertainty in detecting the pollutants dissipation in water
  • Assessing pollutant transport in water
  • Quantitative and qualitative analysis of spatial and spatio-temporal hydrological data
  • Hazards and risks for hydrological series data
  • Impact of climate change on water resource quality
  • Hydrological drought
  • Methods for assessing the interaction between water quality and ecosystems.

Articles presenting new mathematical models that can be validated by statistical methods, for water resources modelling and forecast, are also welcome.

Dr. Alina Barbulescu
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Water quality indicators
  • Groundwater vulnerability
  • Pollutant
  • Statistical methods

Published Papers (13 papers)

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Editorial

Jump to: Research, Review

3 pages, 194 KiB  
Editorial
Assessing Water Quality by Statistical Methods
by Alina Bărbulescu and Cristian Ștefan Dumitriu
Water 2021, 13(8), 1026; https://doi.org/10.3390/w13081026 - 09 Apr 2021
Cited by 14 | Viewed by 2007
Abstract
Water is one of the natural resources most affected by anthropogenic activities, like industry, agriculture, and traffic [...] Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)

Research

Jump to: Editorial, Review

13 pages, 1849 KiB  
Article
Computing the Beta Parameter in IDW Interpolation by Using a Genetic Algorithm
by Alina Bărbulescu, Cristina Șerban and Marina-Larisa Indrecan
Water 2021, 13(6), 863; https://doi.org/10.3390/w13060863 - 22 Mar 2021
Cited by 22 | Viewed by 2668
Abstract
This article proposes a new approach for determining the optimal parameter (β) in the Inverse Distance Weighted Method (IDW) for spatial interpolation of hydrological data series. This is based on a genetic algorithm (GA) and finds a unique β for the entire study [...] Read more.
This article proposes a new approach for determining the optimal parameter (β) in the Inverse Distance Weighted Method (IDW) for spatial interpolation of hydrological data series. This is based on a genetic algorithm (GA) and finds a unique β for the entire study region, while the classical one determines different βs for different interpolated series. The algorithm is proposed in four scenarios crossover/mutation: single-point/uniform, single-point/swap, two-point/uniform, and two-point swap. Its performances are evaluated on data series collected for 41 years at ten observation sites, in terms of mean absolute error (MAE) and mean standard error (MSE). The smallest errors are obtained in the two-point swap scenario. Comparisons of the results with those of the ordinary kriging (KG), classical IDW (with β = 2 and the optimum beta found by our algorithm), and the Optimized IDW with Particle Swarm Optimization (OIDW) for each study data series show that the present approach better performs in 70% (80%) cases. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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24 pages, 6327 KiB  
Article
Integrated Framework for Detecting the Areas Prone to Flooding Generated by Flash-Floods in Small River Catchments
by Romulus Costache, Alina Barbulescu and Quoc Bao Pham
Water 2021, 13(6), 758; https://doi.org/10.3390/w13060758 - 11 Mar 2021
Cited by 14 | Viewed by 2523
Abstract
In the present study, the susceptibility to flash-floods and flooding was studied across the Izvorul Dorului River basin in Romania. In the first phase, three ensemble models were used to determine the susceptibility to flash-floods. These models were generated by a combination of [...] Read more.
In the present study, the susceptibility to flash-floods and flooding was studied across the Izvorul Dorului River basin in Romania. In the first phase, three ensemble models were used to determine the susceptibility to flash-floods. These models were generated by a combination of three statistical bivariate methods, namely frequency ratio (FR), weights of evidence (WOE), and statistical index (SI), with fuzzy analytical hierarchy process (FAHP). The result obtained from the application of the FAHP-WOE model had the best performance highlighted by an Area Under Curve—Receiver Operating Characteristics Curve (AUC-ROC) value of 0.837 for the training sample and another of 0.79 for the validation sample. Furthermore, the results offered by FAHP-WOE were weighted on the river network level using the flow accumulation method, through which the valleys with a medium, high, and very high torrential susceptibility were identified. Based on these valleys’ locations, the susceptibility to floods was estimated. Thus, in the first stage, a buffer zone of 200 m was delimited around the identified valleys along which the floods could occur. Once the buffer zone was established, ten flood conditioning factors were used to determine the flood susceptibility through the analytical hierarchy process model. Approximately 25% of the total delimited area had a high and very high flood susceptibility. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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18 pages, 2605 KiB  
Article
Multivariate Statistical Analysis of Water Quality and Trophic State in an Artificial Dam Reservoir
by Md Mamun, Ji Yoon Kim and Kwang-Guk An
Water 2021, 13(2), 186; https://doi.org/10.3390/w13020186 - 14 Jan 2021
Cited by 32 | Viewed by 4550
Abstract
Paldang Reservoir, located in the Han River basin in South Korea, is used for drinking water, fishing, irrigation, recreation, and hydroelectric power. Therefore, the water quality of the reservoir is of great importance. The main objectives of this study were to evaluate spatial [...] Read more.
Paldang Reservoir, located in the Han River basin in South Korea, is used for drinking water, fishing, irrigation, recreation, and hydroelectric power. Therefore, the water quality of the reservoir is of great importance. The main objectives of this study were to evaluate spatial and seasonal variations of surface water quality in the reservoir using multivariate statistical techniques (MSTs) along with the Trophic State Index (TSI) and Trophic State Index deviation (TSID). The empirical relationships among nutrients (total phosphorus, TP; total nitrogen, TN), chlorophyll-a (CHL-a), and annual variations of water quality parameters were also determined. To this end, 12 water quality parameters were monitored monthly at five sites along the reservoir from 1996 to 2019. Most of the parameters (all except pH, dissolved oxygen (DO), and total coliform bacteria (TCB)) showed significant spatial variations, indicating an influence of anthropogenic activities. Principal component analysis combined with factor analysis (PCA/FA) suggested that the parameters responsible for water quality variations were primarily correlated with nutrients and organic matter (anthropogenic), suspended solids (both natural and anthropogenic), and ionic concentrations (both natural and anthropogenic). Stepwise spatial discriminant analysis (DA) identified water temperature (WT), DO, electrical conductivity (EC), chemical oxygen demand (COD), the ratio of biological oxygen demand (BOD) to COD (BOD/COD), TN, TN:TP, and TCB as the parameters responsible for variations among sites, and seasonal stepwise DA identified WT, BOD, and total suspended solids (TSS) as the parameters responsible for variations among seasons. COD has increased (R2 = 0.63, p < 0.01) in the reservoir since 1996, suggesting that nonbiodegradable organic loading to the water body is rising. The empirical regression models of CHL-a-TP (R2 = 0.45) and CHL-a-TN (R2 = 0.27) indicated that TP better explained algal growth than TN. The mean TSI values for TP, CHL-a, and Secchi depth (SD) indicated a eutrophic state of the reservoir for all seasons and sites. Analysis of TSID suggested that blue-green algae dominated the algal community in the reservoir. The present results show that a significant increase in algal chlorophyll occurs during spring in the reservoir. Our findings may facilitate the management of Paldang Reservoir. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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19 pages, 4588 KiB  
Article
Assessing Land-Cover Effects on Stream Water Quality in Metropolitan Areas Using the Water Quality Index
by TaeHo Kim, YoungWoo Kim, Jihoon Shin, ByeongGeon Go and YoonKyung Cha
Water 2020, 12(11), 3294; https://doi.org/10.3390/w12113294 - 23 Nov 2020
Cited by 8 | Viewed by 6348
Abstract
This study evaluated the influence of different land-cover types on the overall water quality of streams in urban areas. To ensure national applicability of the results, this study encompassed ten major metropolitan areas in South Korea. Using cluster analysis, watersheds were classified into [...] Read more.
This study evaluated the influence of different land-cover types on the overall water quality of streams in urban areas. To ensure national applicability of the results, this study encompassed ten major metropolitan areas in South Korea. Using cluster analysis, watersheds were classified into three land-cover types: Urban-dominated (URB), agriculture-dominated (AGR), and forest-dominated (FOR). For each land-cover type, factor analysis (FA) was used to ensure simple and feasible parameter selection for developing the minimum water quality index (WQImin). The chemical oxygen demand, fecal coliform (total coliform for FOR), and total nitrogen (nitrate-nitrogen for URB) were selected as key parameters for all land-cover types. Our results suggest that WQImin can minimize bias in water quality assessment by reducing redundancy among correlated parameters, resulting in better differentiation of pollution levels. Furthermore, the dominant land-cover type of watersheds, not only affects the level and causes of pollution, but also influences temporal patterns, including the long-term trends and seasonality, of stream water quality in urban areas in South Korea. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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21 pages, 5100 KiB  
Article
Sources, Influencing Factors, and Pollution Process of Inorganic Nitrogen in Shallow Groundwater of a Typical Agricultural Area in Northeast China
by Xinqiang Du, Jing Feng, Min Fang and Xueyan Ye
Water 2020, 12(11), 3292; https://doi.org/10.3390/w12113292 - 23 Nov 2020
Cited by 9 | Viewed by 2447
Abstract
As one of the largest agricultural areas, the Sanjiang Plain of Northeast China has faced serious inorganic nitrogen pollution of groundwater, but the sources and the formation mechanism of pollution in the regional shallow groundwater remain unclear, which constrains the progress of pollution [...] Read more.
As one of the largest agricultural areas, the Sanjiang Plain of Northeast China has faced serious inorganic nitrogen pollution of groundwater, but the sources and the formation mechanism of pollution in the regional shallow groundwater remain unclear, which constrains the progress of pollution control and agricultural development planning. An investigation on potential nitrogen sources, groundwater inorganic nitrogen compounds (NH4+, NO3−, NO2−), and topsoil total nitrogen concentration (TN) was conducted in a typical paddy irrigation area of Sanjiang Plain. Multivariate statistical analysis combined with geospatial-based assessment was applied to identify the sources, determine the governing influencing factors, and analyze the formation process of inorganic nitrogen compounds in shallow groundwater. The results show that the land use type, oxidation-reduction potential (Eh), groundwater depth, NO2− concentration, and electrical conductivity (EC) are highly correlated with the NO3− pollution in groundwater, while DO and Eh affected the distribution of NH4+ most; the high concentrations of NO3− in sampling wells are most likely to be found in the residential land and are distributed mainly in densely populated areas, whereas the NH4+ compounds are most likely to accumulate in the paddy field or the lands surrounded by paddy field and reach the highest level in the northwest of the area, where the fields were cultivated intensively with higher fertilization rates and highest values of topsoil TN. From the results, it can be concluded that that the NO3− compounds in groundwater originated from manure and domestic waste and accumulated in the oxidizing environment, while the NH4+ compounds were derived from N fertilization and remained steady in the reducing environment. NO2− compounds in groundwater were the immediate products of nitrification as a result of microorganism activities. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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25 pages, 5242 KiB  
Article
A Novel Approach to Harmonize Vulnerability Assessment in Carbonate and Detrital Aquifers at Basin Scale
by Leticia Baena-Ruiz and David Pulido-Velazquez
Water 2020, 12(11), 2971; https://doi.org/10.3390/w12112971 - 23 Oct 2020
Cited by 8 | Viewed by 2127
Abstract
The DRASTIC (D: Depth to water; R: Net recharge; A: Aquifer media; S: Soil media; T: Topography; I: Impact of vadose zone; C: Hydraulic conductivity) index is usually applied to assess intrinsic vulnerability in detrital and carbonate aquifers, although it does not take [...] Read more.
The DRASTIC (D: Depth to water; R: Net recharge; A: Aquifer media; S: Soil media; T: Topography; I: Impact of vadose zone; C: Hydraulic conductivity) index is usually applied to assess intrinsic vulnerability in detrital and carbonate aquifers, although it does not take into account the particularities of karst systems as the COP (C: Concentration of flow; O: Overlying layers above water table; P: precipitation) method does. In this paper we aim to find a reasonable correspondence between the vulnerability maps obtained using these two methods. We adapt the DRASTIC index in order to obtain reliable assessments in carbonate aquifers while maintaining its original conceptual formulation. This approach is analogous to the hypothesis of “equivalent porous medium”, which applies to karstic aquifers the numerical solution developed for detrital aquifers. We applied our novel method to the Upper Guadiana Basin, which contains both carbonate and detrital aquifers. Validation analysis demonstrated a higher confidence in the vulnerability assessment provided by the COP method in the carbonate aquifers. The proposed method solves an optimization problem to minimize the differences between the assessments provided by the modified DRASTIC and COP methods. Decision trees and spatial statistics analyses were combined to identify the ranges and weights of DRASTIC parameters to produce an optimal solution that matches the COP vulnerability classification for carbonate aquifers in 75% of the area, while maintaining a reliable assessment of the detrital aquifers in the Basin. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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Graphical abstract

17 pages, 20839 KiB  
Article
Assessing the Groundwater Quality in the Liwa Area, the United Arab Emirates
by Alina Barbulescu, Yousef Nazzal and Fares Howari
Water 2020, 12(10), 2816; https://doi.org/10.3390/w12102816 - 10 Oct 2020
Cited by 9 | Viewed by 3047
Abstract
Last period groundwater quality raises big concerns all over the world since it is a limited source of drinkable water and for agricultural and industrial use. While the suitability of the groundwater of Liwa aquifer (Abu Dhabi Emirate) for agricultural use has been [...] Read more.
Last period groundwater quality raises big concerns all over the world since it is a limited source of drinkable water and for agricultural and industrial use. While the suitability of the groundwater of Liwa aquifer (Abu Dhabi Emirate) for agricultural use has been previously partially studied, not all the water parameters have been taken into account. Therefore, in this paper, we propose the study of 42 concentrations series of 19 groundwater parameters. We test the hypothesis that the water parameters series recorded at different locations are similar and group the samples in clusters. The main parameters that determine the differences between the clusters are determined by Principal Component Analysis (PCA). Finally, we use a quality index for assessing the water suitability for drinking. The conclusions emphasize the necessity of using more than one technique to evaluate water quality for different purposes and to cross-validate the results. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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23 pages, 2890 KiB  
Article
Assessment of Water Quality Using Chemometrics and Multivariate Statistics: A Case Study in Chaobai River Replenished by Reclaimed Water, North China
by Yilei Yu, Xianfang Song, Yinghua Zhang and Fandong Zheng
Water 2020, 12(9), 2551; https://doi.org/10.3390/w12092551 - 12 Sep 2020
Cited by 20 | Viewed by 2851
Abstract
Dry rivers could be effectively recovered by reclaimed water in North China, while river water quality would be an important issue. Therefore, it is important to understand the spatiotemporal variation and controlling factors of river water. Water samples were collected during March, May, [...] Read more.
Dry rivers could be effectively recovered by reclaimed water in North China, while river water quality would be an important issue. Therefore, it is important to understand the spatiotemporal variation and controlling factors of river water. Water samples were collected during March, May, July, September, and November in the year 2010, then 20 parameters were analyzed. The water environment was oxidizing and alkaline, which was beneficial for nitrification. Nitrate was the main nitrogen form. Depleted and enriched isotopes were found in reclaimed water and river water, respectively. Total nitrogen (TN) and total phosphorus (TP) of reclaimed water exceed the threshold of reclaimed water reuse standard and Class V in the surface water quality criteria. Most river water was at the severe eutrophication level. The sodium adsorption ratio indicated a medium harmful level for irrigation purpose. Significant spatial and temporal variation was explored by cluster analysis. Five months and nine stations were both classified into two distinct clusters. It was found that 6 parameters (chloride: Cl−, sulphate: SO42−, potassium: K+, sodium: Na+, magnesium: Mg2+, and total dissolved solids: TDS) had significant upward temporal variation, and 12 parameters (dissolved oxygen: DO, electric conductivity: EC, bicarbonate: HCO3−, K+, Na+, Ca2+, TDS, nitrite-nitrogen: NO2-N, nitrate nitrogen: NO3-N, TN, TP, and chlorophyll a: Chl.a) and 4 parameters (Mg2+, ammonia nitrogen: NH3-N, and the oxygen-18 and hydron-2 stable isotope: δ18O and δ2H) had a significant downward and upward spatial trend, respectively. The Gibbs plot showed that river water chemistry was mainly controlled by a water–rock interaction. The ionic relationship and principal component analysis showed that river water had undergone the dissolution of carbonate, calcite, and silicate minerals, cation exchange, a process of nitrification, photosynthesis of phytoplankton, and stable isotope enrichment. In addition, gypsum and salt rock have a potential dissolution process. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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13 pages, 2855 KiB  
Article
The Impact of Human Interventions and Changes in Climate on the Hydro-Chemical Composition of Techirghiol Lake (Romania)
by Carmen Maftei, Constantin Buta and Ionela Carazeanu Popovici
Water 2020, 12(8), 2261; https://doi.org/10.3390/w12082261 - 12 Aug 2020
Cited by 8 | Viewed by 2633
Abstract
The aim of this study is to establish the potential effect of changes in climate and anthropic interventions made over time on the hydro-chemical properties of the Techirghiol Lake. Located in the littoral region of the Black Sea, Techirghiol Lake is the most [...] Read more.
The aim of this study is to establish the potential effect of changes in climate and anthropic interventions made over time on the hydro-chemical properties of the Techirghiol Lake. Located in the littoral region of the Black Sea, Techirghiol Lake is the most hypersaline lake of Romania—well-known for the therapeutic properties of the saline water and sapropelic mud. Long-term time series of salinity and water level were investigated in relation to the lake water inputs (precipitation, overland flow and groundwater), to chemical parameters (pH, DO and BOD5) and also to the hydraulic works designed and built in the region. The obtained results reveal a degradation of this ecosystem in the period of 1970–1998, when the extensive irrigation practice in the proximity of the lake had a negative effect on the water budget of Techirghiol Lake (an increased freshwater input through runoff and seepage), followed by a major decrease of the lake’s salinity. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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17 pages, 2088 KiB  
Article
Evaluation of the Gulf of Aqaba Coastal Water, Jordan
by Ahmed A. Al-Taani, Maen Rashdan, Yousef Nazzal, Fares Howari, Jibran Iqbal, Abdulla Al-Rawabdeh, Abeer Al Bsoul and Safaa Khashashneh
Water 2020, 12(8), 2125; https://doi.org/10.3390/w12082125 - 27 Jul 2020
Cited by 13 | Viewed by 5455
Abstract
(1) Background: The Gulf of Aqaba (GoA) supports unique and diverse marine ecosystems. It is one of the highest anthropogenically impacted coasts in the Middle East region, where rapid human activities are likely to degrade these naturally diverse but stressed ecosystems. (2) Methods: [...] Read more.
(1) Background: The Gulf of Aqaba (GoA) supports unique and diverse marine ecosystems. It is one of the highest anthropogenically impacted coasts in the Middle East region, where rapid human activities are likely to degrade these naturally diverse but stressed ecosystems. (2) Methods: Various water quality parameters were measured to assess the current status and conditions of GoA seawater including pH, total dissolved solids (TDS), total alkalinity (TA), Cl−, NO3−, SO42−, PO43−, NH4+, Ca2+, Mg2+, Na+, K+, Sr, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn. (3) Results: The pH values indicated basic coastal waters. The elevated levels of TDS with an average of about 42 g/L indicated highly saline conditions. Relatively low levels of inorganic nutrients were observed consistent with the prevalence of oligotrophic conditions in GoA seawater. The concentrations of Ca2+, Mg2+, Na+, K+, Sr, Cl−, and SO42− in surface layer varied spatially from about 423–487, 2246–2356, 9542–12,647, 513–713, 9.2–10.4, 22,173–25,992, and 317–407 mg/L, respectively. The average levels of Cd, Co, Cr, Cu, Fe, Mn, Pb and Zn ranged from 0.51, 0.38, 1.44, 1.29, 0.88, 0.38, and 6.05 µg/L, respectively. (4) Conclusions: The prevailing saline conditions of high temperatures, high evaporation rates, the water stratification and intense dust storms are major contributing factors to the observed seawater chemistry. The surface distribution of water quality variables showed spatial variations with no specific patterns, except for metal contents which exhibited southward increasing trends, closed to the industrial complex. The vast majority of these quality parameters showed relatively higher values compared to those of other regions. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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17 pages, 8567 KiB  
Article
Characteristics and Causes of Long-Term Water Quality Variation in Lixiahe Abdominal Area, China
by Chenjuan Jiang, Jia’nan Zhou, Jingcai Wang, Guosheng Fu and Jiren Zhou
Water 2020, 12(6), 1694; https://doi.org/10.3390/w12061694 - 13 Jun 2020
Cited by 5 | Viewed by 2192
Abstract
The Lixiahe abdominal area is a representative plain river network in the lower reaches of the Huai River, being an upstream section of south-to-north water diversion from the Yangtze River in Jiangsu Province, China. The assessment of long-term water quality variation and the [...] Read more.
The Lixiahe abdominal area is a representative plain river network in the lower reaches of the Huai River, being an upstream section of south-to-north water diversion from the Yangtze River in Jiangsu Province, China. The assessment of long-term water quality variation and the identification of probable causes can provide references for sustainable water resources management. Based on the monthly water quality data of 15 monitoring stations in the Lixiahe abdominal area, the periodic characteristics and tendency of water quality variation were studied by combining wavelet analysis, the Mann–Kendall trend test, and Sen’s slope estimator, and the correlation between water quality variation, water level, and water diversion was discussed with cross wavelet transform and wavelet coherence. The results show that the comprehensive water quality index (CWQI) included periodic fluctuations on multiple scales from 0.25 to 5 years. The CWQI of 7 out of 15 monitoring stations has a significant decreasing trend, indicating regional water quality improvement. The trend slope ranges from −0.071/yr to 0.007/yr, where −0.071/yr indicates the water quality improvement by one grade in 15 years. The spatial variation of water quality in the Lixiahe abdominal area was significant. The water quality of the main water diversion channels and its nearby rivers was significantly improved, while the improvement of other areas was not significant or even became worse due to the increasing discharge of pollutants. The CWQI of the main water diversion channels and its nearby rivers was inversely correlated with the amount of water diversion. The greater the amount of water diversion, the better the water quality. The water diversion from the Yangtze River has played an important role in improving the regional water environment. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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Review

Jump to: Editorial, Research

22 pages, 1397 KiB  
Review
Assessing Groundwater Vulnerability: DRASTIC and DRASTIC-Like Methods: A Review
by Alina Barbulescu
Water 2020, 12(5), 1356; https://doi.org/10.3390/w12051356 - 11 May 2020
Cited by 86 | Viewed by 11105
Abstract
Groundwater vulnerability studies are sources of essential information for the management of water resources, aiming at the water quality preservation. Different methodologies for estimating the groundwater vulnerability, in general, or of the karst aquifer, in particular, are known. Among them, DRASTIC is one [...] Read more.
Groundwater vulnerability studies are sources of essential information for the management of water resources, aiming at the water quality preservation. Different methodologies for estimating the groundwater vulnerability, in general, or of the karst aquifer, in particular, are known. Among them, DRASTIC is one of the most popular due to its performance and easy-to-use applicability. In this article, we review DRASTIC and some DRASTIC-like methods introduced by different scientists, emphasizing their applications, advantages, and drawbacks. Full article
(This article belongs to the Special Issue Assessing Water Quality by Statistical Methods)
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