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1

Investigation of aquifer vulnerability and sensitivity analysis of modified drastic and sintacs models: a case study of Ovogovo Area, Eastern Nigeria

Omeje Emmanuel T., Obiora Daniel N., Okeke Francisca N., Ibuot Johnson C., Ugbor Desmond O., Omeje Victor D.

Acta Geophysica

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2023

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Vol. 71, no. 5

2439--2464

EN

Groundwater serves as a useful source of freshwater to man. Its protection and assessment of potential exposure to contamination are imperative, as its remediation when contaminated is extremely challenging. Vertical electrical sounding was carried out in twenty (21) locations of Ovogovo area with the aim to evaluate the vulnerability of groundwater to pollution, using four vulnerability indexed-based models. Results from DRASTIC AND SINTACS models delineated low and moderate vulnerable zones, while DRASTICLu and SINTACSLu, establishing an index range of 177 to 191 and 160 to 174, respectively, delineated eleven (11) locations as highly vulnerable to contamination. The four models characterized six locations as moderately vulnerable. Statistical summary of DRASTICLu and SINTACSLu models identified high risk of aquifer contamination to originate from recharge and soil media, with a very low risk of contamination, emanating from nature of vadose zone, aquifer nature, topography and land use. Results from single parameter sensitivity and map removal analysis for the modified models delineated depth to water table and land use as the most sensitive parameters in vulnerability assessment of Ovogovo area. Single or multiple map removal analysis identified an increment in sensitivity to vulnerability index as more parameters were being removed. The integration of these vulnerability models and sensitivity analysis enhanced good interpretation of the estimated vulnerable zones. These results will serve as a guide to governmental and non-governmental bodies in understanding the Ovogovo groundwater vulnerability characteristics and sensitization of habitants against indiscriminate disposal of waste and other harmful contaminants for preservation of its groundwater.

2

Determination of Groundwater Vulnerability Using the DRASTIC Method in Ouargla Shallow Aquifer (Algerian Sahara)

Satouh Adel, Boualem Bouselsal, Chellat Smaine, Benaabidate Lahcen

Journal of Ecological Engineering

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2021

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Vol. 22, nr 6

12--19

EN

Groundwater is the main source for many uses around the city of Ouargla. In this study, the DRASTIC method was used to assess the vulnerability of the groundwater aquifer. Seven hydrogeological parameters of the model (D water depth, R efficient charging, A aquifer type, S soil type, T topography, I unsaturated zone and C hydraulic conductivity) were measured and mapped. The intrinsic vulnerability map of the shallow aquifer, using the DRASTIC method, shows a high to very high vulnerability to pollution; 91.6% of the study area has high vulnerability, 8.4% of it has very high vulnerability. The comparison of the DRASTIC maps with the land use map illustrates that the agglomerations and irrigated areas are the most vulnerable areas to pollution, due to the low depth of the aquifer and the infiltration of significant domestic and irrigation wastewater. The results show that the relationship coefficient between the DRASTIC index and nitrate concentration is R = 0.73. This indicates that the groundwater vulnerability mapping by using the DRASTIC method can be applied for sensible groundwater resources management and land-use planning in the study area.

3

Assessment of Groundwater Pollution Vulnerability, Hazard and Risk in a Semi-Arid Region

Haied Nadjib, Khadri Samira, Foufou Atif, Azlaoui Mohamed, Chaab Salah, Bougherira Nabil

Journal of Ecological Engineering

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2021

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Vol. 22, nr 10

1--13

EN

The Mio-plio-quaternary aquifer of the Djelfa Syncline is part of a region in Algeria which is characterized by the lack of surface water resources and located in a semi-arid climate. Since alluvial aquifers, and among them our aquifer, are the most vulnerable because of thier direct exposure to the pollution caused by the infiltrated pollutants, this work focused on the assessement of groundwater pollution vulnerability, hazard and risk. Thus, several methods were used; for this purpose, such as the DRASTIC and WQI methods mapped using a GIS. The results obtained clearly show a low to moderate vulnerability. The DRASTIC model and its validation based on the correlation with WQI revealed a low correlation (WQIvs DI : 0.221). Since the vulnerability model does not match with the groundwater quality, pollution risk was assessed by combining vulnerabilty and hazard (i.e, water quality). The risk map illustrated three levels ranging from low to high risk. This map should be helpful in decision making and groundwater management through avoiding high risk areas.

4

Contribution of a Geographic Information System to Assess the Vulnerability to Groundwater Pollution of the Free Water Table from the Oued Souf Region (South-East Algeria)

Khelfaoui Faycal, Sayad Lamine, Attoui Badra, Bouselsal Bouualem, Ghezaili Salah

Civil and Environmental Engineering Reports

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2021

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Vol. 31, no. 3

1--17

EN

The Oued Souf free aquifer located in the South East of Algeria represents the main water resource used mostly for urban and agricultural activities. The intensive use of chemical fertilizers has led to serious environmental problems such as contamination of the free aquifer in the region. Thus, aquifer vulnerability has been assessed using several different methods (DRASTIC, GOD, and the Susceptibility Index ‘SI’) based on a geographic information system (GIS). For each method, two vulnerability maps have been developed in the years 2002 and 2012. These maps show that the study area is more exposed to urban, and especially agricultural, pollution. Two classes of vulnerability (moderate and high) have been identified by both DRASTIC and GOD methods. A combined analysis reveals that the moderate class showing 48% (for the GOD method), and the high class showing 57% (for the DRASTIC method) are the most dominant. However, the Susceptibility Index method (SI) revealed that the vulnerability varies from moderate to very high-level classes. In 2012, about of 53% of the study area was dominated by moderate vulnerability classes. The high vulnerability class also includes a considerable part of the land (41%) around urban or strongly agricultural areas, while only 6% is under very high vulnerability groundwater contamination. In addition, a marked decrease in the vulnerability level was noticed in 2012 compared to 2002. This decrease is mainly due to the lowering of the water table after the installation of a vertical drainage network to evacuate the surplus water to the depression and Chotts areas in the North of the region. These results provide a guide for decision-makers involved in the protection of groundwater pollution in such a vulnerable area.

5

Podatność wód podziemnych w warunkach suszy hydrogeologicznej w płytkich systemach hydrogeologicznych

Krogulec Ewa, Sawicka Katarzyna, Zabłocki Sebastian

Biuletyn Państwowego Instytutu Geologicznego

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2019

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nr 475, Hydrogeologia z. 16

101--108

PL

Badania podatności wód podziemnych przeprowadzono w dolinie Wisły, na obszarze płytkiego występowania wód podziemnych. Wykonano analizę zmian stanów wód podziemnych w celu identyfikacji wartości średnich oraz wartości najniższych w wieloleciu 1999–2013. Na modelu hydrodynamicznym określono wartości zasilania infiltracyjnego odpowiadające stanom średnim w wieloleciu oraz stanom najniższym w warunkach suszy hydrogeologicznej. Przeprowadzono wariantową ocenę podatności wód podziemnych na zanieczyszczenia przy zastosowaniu metody DRASTIC, przyjmując do obliczeń średnie i najniższe stany wód podziemnych i odpowiadające im wartości zasilania infiltracyjnego. Mapy podatności dla obu wariantów podatności: podatności średniej (A) oraz w warunkach suszy hydrogeologicznej (B), przedstawiają zróżnicowanie przestrzenne występowania poszczególnych klas podatności. W wariancie A największą powierzchnię zajmuje średniowysoka i średnia klasa podatności. W okresie suszy hydrogeologicznej największą powierzchnię zajmuje średnia klasa podatności. Wyniki badań potwierdzają potrzebę wariantowej oceny podatności, szczególnie w płytkich systemach hydrogeologicznych, w których objęte są ochroną zróżnicowane ekosystemy, w tym ekosystemy zależne od wód podziemnych.

EN

The study of groundwater vulnerability was carried out in the Vistula river valley, in the area of shallow groundwater occurrence. An analysis of groundwater level changes was preformed to identify average values and the lowest values in the period of 1999–2013. On the hydrodynamic model, infiltration rate was determined corresponding to average groundwater levels and the lowest levels representing hydrogeological drought. A variant evaluation of groundwater vulnerability to pollutions was done using the DRASTIC method, assuming the average and the lowest groundwater levels and the corresponding infiltration rates for the calculation. The vulnerability maps for both vulnerability options: medium (A) and hydrogeological drought conditions (B), show the spatial diversity of individual vulnerability classes. In Variant A, the medium and medium high classes occupy the largest area. During the hydrogeological drought the medium class is the largest area. The research results support the need for a variant susceptibility assessment, especially in shallow hydrogeological systems in which diverse ecosystems are protected, including groundwater-dependent ecosystems.

6

Assessment of Pollution Risk Mapping Methods in an Eastern Mediterranean Catchment

Michalopoulos D., Dimitriou E.

Journal of Ecological Engineering

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2018

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Vol. 19, nr 1

55--68

EN

The protection and preservation of good groundwater quality is of critical importance worldwide, nowadays. Increasing urbanization, economic development and agricultural activities, combined with limited precipitation contribute to the quantitative and qualitative degradation of groundwater resources, especially in the eastern Mediterranean region. For this purpose, a series of actions are implemented including groundwater vulnerability mapping that can depict prone to pollution aquifers which need protection and/or restoration measures. In this study, the efficiency of two well-known methodologies (COP and DRASTIC) for groundwater vulnerability and pollution risk mapping was assessed in the Sperchios river basin. The vulnerability and pollution risk maps of the two methodologies were spatially compared to each other and the observed similarities and differences were discussed and explained. The output of the study shows that in the particular geoenvironmental conditions DRASTIC method performs better than the COP, particularly in the lowland, porous media aquifer.

7

Hydrogeochemical Characterization and Vulnerability Assessment of Shallow Groundwater in Basement Complex Area, Southwest Nigeria

Adewumi A. J., Anifowose A. Y. B., Olabode F. O., Laniyan T. A.

Contemporary Trends in Geoscience

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2018

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Vol. 7, iss. 1

72--103

EN

Thirty-five (35) groundwater samples from Owo area were analyzed for physicochemical parameters. Results show that the mean value of pH is 6.32, TDS is 208.92 mg/l, temperature is 28.77oC, EC is 545.16 μs/cm; TH is 111.09 mg/l, SO4 is 71.73 mg/l, Cl is 0.07 mg/l, HCO3 is 14.09 mg/l, Na is 25.06 mg/l, Ca is 37.07 mg/l, K is 24.36 mg/l and Mg is 4.41 mg/l. The results were compared to the WHO and NDSQW standards. All parameters were within the permissible limit except EC in well OW6 and K is above the stipulated standards in 69% of the total samples. The high concentration of K is linked to the use of NPK fertilizer in the area for agricultural purposes. The groundwater belongs to Ca-Na-K-SO4 and Na-Ca-SO4 water type respectively. The ionic concentration in the groundwater is due to the dissolution of the rock that makes up the aquifer. Plagioclase and silicate-bearing rocks are the sources of major ions in the water. SAR, PI, RSBC and KR reveals that groundwater in the area is good for irrigation purpose. DRASTIC model further revealed that groundwater in the area is less vulnerable to contamination under the current environmental conditions.

8

Niepewność oceny podatności wód podziemnych na zanieczyszczenia dla obszarów miejskich na przykładzie warszawskiej dzielnicy Bielany

Krogulec E., Trzeciak J.

Przegląd Geologiczny

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2017

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Vol. 65, nr 11/1

1090--1095

EN

Groundwater vulnerability assessment is an important environment management tool. In this study assessment of groundwater vulnerability to pollution was conducted by DRASTIC method in urban area, represented by the Bielany - district of Warsaw. The results of this study showed that 70% of the study area has medium or moderately high pollution potential and nearly 30% area has low and very low pollution potential. Two sensitivity tests were performed: the map removal sensitivity analysis and the single-parameter sensitivity analysis. Sensitivity analysis is defined as the evaluation of the effect of changes of input values on the output of the model, therefore, in order to reduce subjectivity of groundwater vulnerability assessment sensitivity analysis was performed for DRASTIC procedure. Both tests highlighted the role of the parameter „depth to water" in groundwater vulnerability assessment.

9

Ocena podatności na zagrożenia wód podziemnych metodą DRASTIC we wschodniej części Drawieńskiego Parku Narodowego

Stańczak E.

Przegląd Geologiczny

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2015

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Vol. 63, nr 10/2

1074--1079

EN

In article shown question vulnerability to contamination, natural characteristic of groundwater, for the eastern part of Drawa National Park (DNP). To vulnerability assessment used usually known range DRASTIC method. Based on input data determined pixel size of map Δx = Δy = 50 m. The DRASTIC parameters were exactly checked. One of the most important recharging infiltration (162.5 mm/year), compared with result of hydrological method. It shown similar value and this data are reliable. By means of GIS analysis calculated the DRASTIC index. Visualization superficial distribution of classes of vulnerability is shown as map of groundwater vulnerability. The results indicate that more than 90% study area is located high vulnerability class.

10

Praktyczne aspekty oceny podatności wód podziemnych na zanieczyszczenie metodą drastic

Kondratiuk P.

Ekonomia i Środowisko

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2013

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nr 4

87--95

PL

Wody podziemne są jednym z ważniejszych abiotycznych elementów środowiska przyrodniczego, w stosunku do którego prowadzi się działania ochronne. W większości kraju są one bowiem podstawowym źródłem wody pitnej i na potrzeby gospodarcze. Coraz większą uwagę zwraca się na procedury pozwalające zminimalizować zagrożenie zanieczyszczenia tych wód. W praktyce, w wyraźny sposób, znajduje to odzwierciedlenie w raportach oddziaływania na środowisko sporządzanych przy realizacji inwestycji zagrażających środowisku. Często istotnym, a w wielu przypadkach niezbędnym elementem takiego raportu jest ocena podatności wód podziemnych na zanieczyszczenia.

EN

Assessment of groundwater vulnerability to pollution is important for its utilization and the resources protection. The DRASTIC model is one of the mostly often used models for groundwater vulnerability assessment. The model uses seven environmental parameters. The model can be modified, basing on local hydrogeological conditions, in order to obtain more reliable results. In this study two variants of the model were tested. It was found that the DRASTIC model in the environmental conditions of NE Poland gives correct, sensible results and should be recommended for practical use. However, standardization of the method would be a good idea and would make the method more widely applicable.

11

Podatność naturalna i specyficzna wód podziemnych na zanieczyszczenia w dolinie rzecznej

Krogulec E.

Biuletyn Państwowego Instytutu Geologicznego

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2011

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nr 445 Hydrogeologia z. 12/1

337--343

PL

Badania podatności wód podziemnych na zanieczyszczenia zostały przeprowadzone dla obszaru Kampinoskiego Parku Narodowego (KPN) i jego otuliny. Ocenę podatności naturalnej przeprowadzono przy zastosowaniu metody DRASTIC, natomiast do oceny podatności specyficznej wykorzystano rozszerzoną formułę DRASTIC uwzględniającą potencjalne ryzyka związane z zagospodarowaniem terenu oraz wskaźnik określający potencjalne zagrożenie zanieczyszczeniem wód podziemnych azotanami. Obszar badań charakteryzuje się średnio wysoką (51% obszaru) i średnią (37% obszaru) podatnością naturalną na zanieczyszczenie. Pozostałe klasy podatności występują na znacznie mniejszym obszarze. Ocena podatności specyficznej wskazuje, że na obszarze badań występuje głównie średnio wysoka (55% obszaru) i średnia (33% obszaru) podatność specyficzna, po uwzględnieniu potencjalnego zagrożenia wód podziemnych związanego z zagospodarowaniem terenu, oraz niska (68% obszaru) i średnia (22% obszaru) podatność po uwzględnieniu wskaźnika określającego zagrożenie zanieczyszczeniem azotanami.

EN

The research of groundwater vulnerability to contamination has been conducted in the area of Kampinoski National Park (KNP) and its buffer zone. The assessment of the intrinsic vulnerability has been carried out using a method of DRASTIC while to assess the specific vulnerability an extended formula of DRASTIC has been used. The extended formula considers the potential risks associated with land development and an indicator quantifying the groundwater potential risk of nitrate. The study area is characterized by medium-high (51% of the area) and average (37% of the area) of intrinsic vulnerability to contamination. Other classes of vulnerability occur on a much smaller area. The assessment of specific vulnerability indicates that on the study area, after taking into account the potential risk of groundwater associated with land development, there is mainly medium-high (66% of the area) and medium (33% of area) vulnerability, however after taking into account an indicator quantifying the groundwater potential risk of nitrate, the vulnerability is low (68% of the area) and medium (22% of the area).

12

Zasięg zruszenia górotworu jako element oceny podatności wód podziemnych na zanieczyszczenie wywołane zatapianiem KWK „Grodziec”.

Góra W.

Bezpieczeństwo Pracy i Ochrona Środowiska w Górnictwie

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2011

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nr 4

16-22

PL

W artykule przedstawiono propozycję sposobu oceny jednego z czynników zagrożenia jakości wód podziemnych poziomów wodonośnych w nadkładzie karbonu w GZW związanego z zatapianiem zlikwidowanych zakładów górniczych, zbliżonego konstrukcyjnie do sposobu oceny podatności wód podziemnych na zanieczyszczenie metodą DRASTIC. Proponowany sposób oceny czynnika górniczego, jakim jest zasięg zruszenia górotworu, opiera się na określeniu prawdopodobnego zasięgu stref deformacji górotworu ponad wyrobiskami w pokładach węgla oraz nadaniu im odpowiedniej rangi zależnie od ocenionej przepuszczalności w związku z powstawaniem sieci szczelin poeksploatacyjnych.

EN

The article presents a proposal of assessment of one of the threat factors to the quality of waters of underground water-carrying levels in the surplus of carbon in the Upper-Silesian Coal Basin connected with flooding of abandoned mining plants, which is similar in construction to the assessment of underground waters susceptibility to contamination with the DRASTIC method. The proposed assessment of mining factor, which is the rangę of rocks disturbance, is based upon the determination of the probable rangę of orogen deformation zones over the excavations in the coal deposits and assigning them to the appropriate rank depending on the assessed permeability in connection with the formation of post-exploitation cracks.

13

Wpływ skali rozpoznania na ocenę podatności wód podziemnych na zanieczyszczenia na przykładzie badań w Kampinoskim Parku Narodowym

Krogulec E., Trzeciak J.

Biuletyn Państwowego Instytutu Geologicznego

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2009

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nr 436, z. 9/1

289-293

PL

Mapy podatności naturalnej wód podziemnych na zanieczyszczenia stanowią wizualizację oceny podatności wód podziemnych na zanieczyszczenia. Są one jednym z najważniejszych elementów uwzględnianych przy podejmowaniu decyzji odnośnie zagospodarowania terenu i obiektów potencjalnie uciążliwych dla środowiska. Badania podatności wód podziemnych na zanieczyszczenia zostały przeprowadzone na obszarze Kampinoskiego Parku Narodowego (skala regionalna) oraz na wytypowanym poligonie w pobliżu Wiktorowa w Kampinoskim Parku Narodowym (około 30 km2) w skali lokalnej. Ocenę podatności naturalnej przeprowadzono przy zastosowaniu zmodyfikowanej metody DRASTIC oraz na podstawie szacunku czasu przesączania się zanieczyszczeń konserwatywnych. Uzyskane rezultaty wskazują, że rezultat oceny zależy od wykorzystanej metody, stopnia rozpoznania warunków hydrogeologicznych, zastosowanych uproszczeń oraz wyznaczonego celu badań.

EN

Maps of natural groundwater vulnerability to contamination illustrate the assessment of natural groundwater vulnerability. They are also one of the important components that are taken into consideration while making a decision as regards the site management and objects potentially troublesome for the environment. The researches of natural vulnerability were conducted for the area of the Kampinoski National Park (on a regional scale) and for the area (about 30 km2) near Wiktorów (part of the Kampinos National Park) on a local scale. The assessment of vulnerability has been performed with the use of the modified DRASTIC method and calculations of the time migration method of a contaminant through the unsaturated zone. The results of the study indicate that the evaluation of natural groundwater vulnerability to contamination depends on the following factors: research methodology, degree of area recognition, applied simplifications and the purpose of research.

14

Możliwości zastosowania wybranych metod oceny podatności na zmiany w środowisku gruntowo-wodnym w północno-wschodniej części Górnośląskiego Zagłębia Węglowego

Góra S., Szczepański A.

Biuletyn Państwowego Instytutu Geologicznego

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2009

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nr 436, z. 9/1

115-119

PL

Wieloletnia działalność górnictwa na obszarze Górnośląskiego Zagłębia Węglowego spowodowała znaczne przekształcenia środowiska naturalnego, włączając środowisko wód podziemnych. Kopalnie węgla likwidowane poprzez częściowe lub całkowite zatopienie stwarzają zagrożenie dla jakości wód podziemnych nieuwzględniane dotąd w ocenach podatności wód podziemnych na zanieczyszczenie. W artykule przedstawiono wpływ górniczych przekształceń środowiska na możliwość zastosowania wybranych metod oceny podatności w obrębie północno-wschodniej części GZW.

EN

Long-term mining activity in the USCB caused significant transformation of the environment, including the groundwater environment. Coal mines abandoned by partial or total flooding generate hazard for groundwater quality that has not been so far taken into consideration in groundwater vulnerability assessment methods. The authors present the above-mentioned issue for the hydrogeologically out-ropped sub-region of the USCB, including consideration of coal mine abandoning and partial flooding.

15

Evaluation of intrinsic vulnerability of an Upper Jurassic karst-fissured aquifer in the Jura Krakowska (southern Poland) to anthropogenic pollution using the DRASTIC method

Różkowski J.

Geological Quarterly

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2007

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Vol. 51, No 1

17-26

EN

This paper demonstrates the evaluation of in trinsic vulnerability of karst-fissured waters in an Upper Jurassic aquifer by applying modified DRASTIC method. The area investigated is the Jura Krakowska (South Poland) - an area of upland merokarst (or relictkarst), where the Upper Jurassic aquifer is mainly unconfined. The method applied is a combination of a simulation model of the ground water aquifer (factors: netre charge, hydraulic conductivity, ground wa ter flow velocity in the aquifer) and a geographical in formation system - GIS model (depth of ground water table, lithology of vadosezone, thickness of Upper Jurassic aquifer), and additionally a soil factor was taken into account. In the area of the Jura Krakowska, 5 classes of intrinsic vulnerability to pollution were distinguished according to the values of vulnerability factors. These classes range from extremely high to low vulnerability (IP 200-50). Based on the synthetic map of vulnerability it emerges that high vulnerability indices cover 54% of the area studied while medium and low vulnerability indices cover 46% of this area. The modified DRASTIC method presented seems to be a useful tool to evaluate the intrinsic vulnerability of karst-fis sured aquifers of "Torcal" type with a scattered system of recharge and discharge, and a thick vadosezone of variable permeability. This is consistent with the method developed with European programme COST ACTION 620. All rating methods recommended for karst have limitations, there fore the method applied is constantly updated. Many of them are particularly use ful for areas of bare karst, mountain systems of "Aliou" type and in ar eas of complete karst develop ment (holokarst).

16

Methods and results of groundwater vulnerability evaluation to contamination in the Kampinoski National Park, central Poland

Krogulec E.

Acta Geologica Polonica

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2006

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Vol. 56, no. 3

349-359

EN

Aquifer vulnerability maps are valuable tools for communicating concerns about the level of groundwater pollution hazard to local landuse planners and to the general public. Groundwater vulnerability to contamination in the Kampinoski National Park (KNP) area in central Poland was evaluated as a basis for developing appropriate protection strategy for the groundwater resources and management in recreation areas located near Warsaw. Assessment was accomplished using U.S. EPA DRASTIC and the residence time in the unsaturated zone of a conservative pollutant. The final DRASTIC values have been grouped into medium (37 % of area) and medium high (52 %) intrinsic vulnerability categories. The residence time in the unsaturated zone is classified in 11 intervals, ranging from 30 days to 30 years, but nearly 75 % of the study area is characterized by intervals from 1 to 3 years.