Mohammed Freeh Sahab*
| Mohammed Hatem Abdullah | Ghassan Abbas Hammadi | Noor Sami Hamad | Abuobaydah Ayad Abdulazez | Aymen Hameed Fayyadh | Duaa Jassim Ayed | Arkan Dhari Jalal | Khamis Naba Sayl | Majeed Mattar Ramal
© 2024 The authors. This article is published by IIETA and is licensed under the CC BY 4.0 license (http://creativecommons.org/licenses/by/4.0/).
OPEN ACCESS
This study was conducted during the summer season of 2023 to assess the groundwater quality in the Al-Wafaa region of Anbar Province western Iraq for irrigation purposes.18 water samples were collected from 18 wells Distributed in the study area. pH, EC, Total Dissolved Solid (TDS), main cations, and anions (Na+, K+, Ca2+, Mg2+, Cl-, HCO3-, NO3-) were measured. The main cations were used to calculate the Percent Sodium (%Na) and Sodium Adsorption Ratio (SAR). Additionally, Wilcox and United States Salinity Laboratory (USSL) diagrams were employed to evaluate the suitability of the groundwater for irrigation. The study found that based on the EC values; all groundwater in the research area is classified as having very high salinity and is therefore not suitable for irrigation. Based on the Wilcox diagram, 83% of the well water samples in the Al-Wafaa region are classified as unsuitable for irrigation, and 17% fall within a doubtful to unsuitable category. According to the USSL diagram, 22% of groundwater samples are in the C4S3 category, indicating very high salinity with high sodium. Additionally, 61% of samples fall into the C4S2 category, suggesting very high salinity with medium sodium, and 17% of samples fall into the (C4S1) category, indicating very high salinity with low sodium. Overall, the findings indicate that the samples are not suitable for crop watering.
assessment, irrigation, groundwater quality, hazard, percent sodium, electrical conductivity (EC), Wilcox, United States Salinity Laboratory
In many countries of the world, groundwater is an important source for irrigation of agricultural lands, so groundwater quality evaluation has become a necessary task for managing groundwater quality in the future. In Iraq, the water of the Tigris and Euphrates rivers is considered an important source of drinking water, crop irrigation, and other purposes, but in recent years many problems have appeared that affected the river water quality such as the lack of rainfall and increased pollution. Therefore, it is necessary to search for other sources of water and hydrological evaluation of the well water location. Well water is taken into consideration the high-quality source for irrigating agricultural lands, it is possible to drink, and it is supposed to be dependable and free of contaminants, suspended substances, and sickness-causing microorganisms [1]. Several factors impact the willpower of the suitability charge of water for irrigation, together with water fine, climate, plant capacity to tolerate excessive salinity, soil type, and water drainage [2]. Modern innovations and techniques were utilized to evaluate and observe groundwater for irrigation. Some of these innovations used included irrigation water indicators like sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) [3]. The Water Quality Index (WQI) is a very suitable and powerful approach to evaluate the appropriateness of water best [4]. Many researchers have investigated the valuation of groundwater to irrigate crops and human utilization, specifically in Iraq and comparable arid regions in the world. Allawi et al. [5] presented research to evaluate groundwater quality within the Alnekheeb basin in western Iraq to perceive an extra applicable and sustainable water delivery. In this research, three groundwater water first-rate signs, hardness, SAR, and salinity, are forecast by employing two primarily based on artificial intelligence fashions, the Radial Basis Neural Network (RBF-NN) and the Probabilistic Neural Network (PNN). Furthermore, this study focused on the impact of enters parameters on the overall performance of the advised models. According to the evaluation results, adding greater information variables may once in a while enhance the efficacy of the advised models in forecasting accuracy. The outcomes indicate that the PNN model has an amazing overall performance in forecasting groundwater water exceptional matrices, outperforming the RBF-NN version. Khudair et al. [6] presented a study in 2021 to assess the quality of groundwater in the Al-Qaim metropolis, western Iraq, to irrigate crops within the research area. The research tested seven places in the study location to determine the effectiveness of irrigation. The pH, electric conductivity (EC), important cations, and anions (K, Na, Mg2, Ca2, HCO3, Cl-, SO4), and CO3 have been determined. The effects revealed that the examined water is suitable for crop watering regarding pH cost and EC. The total hardness values have been modest and did now not represent trouble, and the main cations and anions have been in the acceptable degrees for the indicated classes. The SAR was determined to be in magnificence S1, indicating that the groundwater in the research district is suitable for crop watering. Ghalib [7] conducted research to estimate the quality of groundwater satisfaction in Wasit province, Iraq. The physicochemical traits, consisting of total dissolved strong, important cation and anions, pH, and EC, have been utilized to estimate groundwater high-quality for human use and crop watering by comparing them to World Health Organization and Iraqi standards. TDS, sodium adsorption ratio, residual sodium bicarbonate, permeability index (PI), and magnesium ratio were used to determine irrigation appropriateness. The examined groundwater samples have been oversaturated with carbonate minerals and lacking evaporated minerals. The effects found that almost all of the groundwater samples were hazardous for drinking and irrigation because of salt and salinity risks. The present study has evaluated the quality of groundwater in a 5119 km2 area in Babylon City, Iraq [8]. This research included well positions, maps, and data about the quality of groundwater provided by way of the special government. The WQI and IWQI were decided for groundwater samples using some characteristics such as EC, Cl-, HCO3-, Na, and pH. Furthermore, groundwater suitability for watering is assessed by the use of some Indicators which include Kelly's Ratio (KR), SAR, and PI. Water Quality Indicator graphs were made using the Geographical Information System (GIS) surroundings. The findings show that the groundwater inside the research region needs particular treatments to be appropriate for use. Awad et al. [9] focused on studying the hydrogeochemical properties of groundwater, consisting of ion change, salinization, and hydrochemistry in the Green Belt area in northern Najaf province, Iraq. Also targeted the research on the evaluation of the pleasant of groundwater for crop watering based on the IWQI for thirteen parameters and groundwater quality indices such as TDS, EC, SAR, overall hardness (TH), PI, KR, and magnesium hazard ratio (MHR). The results indicate that groundwater inside the research district is incorrect for crop watering. To ensure the sustainability of groundwater applications, a continuous tracking program and appropriate control techniques. Al-Tameemi et al. [10] assessed the quality of groundwater in Kirkuk province, northern Iraq, for human uses, crop watering, leisure activities, and animal uses from 2017 to 2019, using the Canadian Water Quality Index (CWQI) and GIS. The groundwater quality was tested using Iraqi and World Health Organization (WHO) suggestions as well. The Iraqi standards were utilized for drinking water, whereas WHO standards were applied for watering, leisure activities, and animal purposes. Based on the CWQI, groundwater samples were classed as medium in 2017 and 2018, while there was unsafe drinking water detected in 2019. Al-Kubaisi et al. [11] presented an article to assess the groundwater for irrigation in the Al-Dabdaba aquifer in Karbala - Najaf Plateau in Iraq. The research blanketed mapping of the water quality index and the outcomes labeled the groundwater inside the Al-Dabdaba layer as having moderate. Soren et al. [12] used Wilcox and USSL schemes to evaluate groundwater first-class for irrigation and drinking functions in South 24-Parganas in West Bengal, India. The results confirmed that 46% of the samples had been categorized under the coolest to the permissible category and 37% were categorized below the permissible to questionable class. Sadashivaiah et al. [13] applied the technique of SAR, RSC, salinity hazards, and USSL chart to evaluate water for irrigation purposes in Tukur Taluk. The findings from USSL charts showed that the samples are classified as suitable for irrigation purposes and are classified in the suitable range for irrigation from SAR or RSC values. Hydrochemistry of groundwater in the Ain Azel plain, Algeria was used to evaluate groundwater for irrigation and the results showed that most of the samples are located in the area (C3-S1), meaning the risk of salinity is high and the risk of sodium is low [14]. The groundwater quality for irrigation purposes was evaluated in the city of Acarão Basin in Brazil by developing an IWQI depending on several parameters such as (EC, CL, HCO3, Na) [15]. The study showed the risk of soil salinity and water venomousness in the crops. Siswoyo et al. [16] presented a study to evaluate groundwater to irrigate agricultural lands in the Jombang region, East Java, Indonesia. The study relied on IQWI techniques, and the results classified the groundwater quality between moderate restriction and low irrigation restriction. A study was presented to evaluate the groundwater quality for irrigation of agricultural lands in three villages in Iran using a combination of geographic information systems and the irrigation water quality index [17]. Ketata et al. [18] used IWQI as a device to manage groundwater nice within the El Khairat Deep aquifer inside the Tunisian Sahel. Nastos et al. [19] used artificial neural networks to forecast rainfall intensity for four months. The results simulations from the model showed decent forecasting of rainfall intensity values. Using artificial neural networks (ANN) for forecasting the water level of the Euphrates rivers in western Iraq and the result showed the artificial neural networks can valued water level (t+1) with a high grade accuracy [20]. Modeling approaches used in hydrological and hydraulic processes are required to provide accurate and sustainable water resource management [21].
Al-Waffa area is a semi-desert region with no surface water, so groundwater is essential to meet the water needs for irrigation and drinking purposes. This research aims to assess the groundwater quality for irrigation purposes.
Al-Wafaa is an area located in western Iraq, west of Anbar province, 50 km west of Ramadi. The study area is located between latitudes (33°23'51" N) and longitudes (42°51'11" E) The area is about 100 km2 and has a population of about 8000 people. The Euphrates River flows east of the research region shown in Figure 1. The environment of the region is a very hot desert with and dehydrated summer with a high amount of evaporation and a cold season with a reduction in rainfall. It is characterized by simple slop and presence of the seasonal valleys such as Al-Asal Valley [22]. It is affected by the Abu Al-Jir area fault [23]. The area is also rich in bitumen and sulfates and the area is characterized by the presence of an unconfined aquifer consisting of sandstone with fine gravel and mudstone, covered with a layer of gypsum and sandy soil. Groundwater is extracted in this area by drilling wells [24].
Figure 1. The map of the study area
3.1 Collection of samples
Eighteen wells were selected in the study area shown in Figure 2. The wells' coordinates were determined via (GPS) and documented in Table 1. The samples were collected in August 2023 and kept in 2-liter clean and dry plastic bottles and transferred to the water quality control laboratory at the College of Engineering, Anbar University for the measurement of chemical parameters.
Figure 2. Location of the wells
Table 1. The coordinates of wells in the Al-Wafaa region
|
Wells No. |
The Coordinates |
Wells No. |
The Coordinates |
|
1 |
N 33° 17' 31.57" E 42° 37' 35.40" |
10 |
N 33° 15' 22" E 42° 53' 23" |
|
2 |
N 33° 20' 28" E 42° 47' 35" |
11 |
N 33° 26' 10" E 42° 43' 24" |
|
3 |
N 33° 23' 16" E 42° 50' 37" |
12 |
N 33° 25' 42" E 42° 49' 43" |
|
4 |
N 33° 25' 42" E 42° 43' 43" |
13 |
N 33° 17' 18" E 42° 51' 30" |
|
5 |
N 33° 25' 54" E 42° 49' 47" |
14 |
N 33° 23' 25" E 42° 51' 03" |
|
6 |
N 33° 26' 08" E 42° 46' 34" |
15 |
N 33° 25' 19" E 42° 50' 06" |
|
7 |
N 33° 25' 51" E 42° 49' 04" |
16 |
N 33° 25' 35" E 42° 49' 48" |
|
8 |
N 33° 23' 33" E 42° 51' 23" |
17 |
N 33° 16' 18" E 42° 46' 56" |
|
9 |
N 33° 15' 58" E 42° 53' 58" |
18 |
N 33° 25' 20" E 42° 50' 01" |
3.2 Lab analysis of samples
Water samples were analyzed for chemical parameters: pH, EC, TDS, Calcium (Ca2+), Magnesium (Mg2+), Sodium (Na+), Potassium (K+), Sulphate (SO4-2), Chloride (Cl-1) and Bicarbonate (HCO3-1). pH, EC, and TDS are important parameters for assessing groundwater for several purposes. All parameters were examined depending on the Standard Method for the Examination of water and wastewater following (APHA, 1998) American Public Health Association guidelines [25]. Conductivity and pH were measured by using a portable device pH/EC/ meter (HANNA HI9321). TDS, bicarbonate (HCO3−), chloride (Cl−), magnesium (Mg2+), and calcium (Ca2+) were analyzed by titration methods; potassium (K+) and sodium (Na+) were tested using the flame photometric method by flame photometer (Jenway PFP7); and sulfate (SO42−) were analyzed by spectrophotometer (DR 5000 HACH).
3.3 Calculation of water quality indices for irrigation
There are several key parameters to consider when evaluating the quality of irrigation water. These include pH, salinity levels, bicarbonate concentration (which is related to calcium and magnesium levels), and the presence of components such as sodium and chloride, which can be harmful to plants. To assess the suitability of groundwater for irrigation, water quality indices like the SAR and %Na are commonly used. In addition, graphical methods like the Wilcox diagram and USSL diagram are frequently employed to confirm the suitability of groundwater for irrigation purposes.
3.3.1 SAR
The Sodium Adsorption Ratio is considered an important factor to assess the groundwater quality and it was calculated using the equation given by Raghunath [26]. The ion concentration was measured in (meq/l).
$\mathrm{SAR}=\frac{{Na}^{+}}{\sqrt{\left({Ca}^{2+}+{Mg}^{2+}\right) / 2}}$ (1)
3.3.2 %Na
%Na was calculated by the equation given by Todd and Mays [27]. The ion concentration was measured in (meq/l).
$\% \mathrm{Na}=\frac{{Na}^{+}+{K}^{+}}{{Ca}^{2+}+{Mg}^{2+}+{Na}^{+}+{K}^{+}} \times 100$ (2)
3.3.3 USSL diagram
Proposed chart for classification of groundwater quality for irrigation purposes. The classification depends on values of SAR and EC [28]. The irrigation water quality is classified as follows (Table 2).
Table 2. Classification of groundwater for irrigation purposes
|
Classification of Groundwater for Irrigation Purposes |
|
|
EC (ms/cm) |
SAR (mg/l) |
|
C1 - low salinity risk |
S1 - low sodium (alkali) risk |
|
C2 - medium salinity risk |
S2 - medium sodium (alkali) risk |
|
C3 - high salinity risk |
S3 - high sodium (alkali) risk |
|
C4 It means very high salinity risk |
S4 - very high sodium (alkali) risk |
3.3.4 Wilcox diagram
Proposed chart for classification of groundwater for irrigation purposes. The classification depends on values of %Na and EC [29]. The chart is classified into five categories such as: Excellent to Good, Good to permissible. Permissible to doubtful, Doubtful to unsuitable, and Unsuitable.
4.1 Water quality based on the absolute ions
The concentration of cations in the study region ranges from 179 to 429 mg/l for Ca2+, 72 to 283 mg/l for Mg2+, 251 to 708 mg/l for Na+, and 4 to 128 mg/l for K+ (Table 3). The allowed levels for Ca2+, Mg2+, Na+, and K+ in irrigation water are 80, 35, 200, and 30 mg/l, respectively [26]. Based on these acceptable levels, 0% of groundwater samples were suitable for Ca2+, Mg2+, and Na+, while 72% were suitable for K+, and 28% were not suitable.
Table 3. Analysis results of water sample
|
Well No. |
pH |
EC (ms/cm) |
TDS (mg/l) |
Ca2+ (mg/l) |
Mg2+ (mg/l) |
K+ (mg/l) |
Na+ (mg/l) |
HCO3-1 (mg/l) |
SO4-2 (mg/l) |
Cl-1 (mg/l) |
|
1 |
7.19 |
4220 |
2734 |
320 |
161 |
29 |
430 |
510 |
674 |
636 |
|
2 |
7.25 |
5080 |
1600 |
191 |
121 |
12 |
684 |
164 |
592 |
305 |
|
3 |
7.21 |
5310 |
3440 |
216 |
146 |
16 |
708 |
435 |
1223 |
651 |
|
4 |
7.23 |
5210 |
3380 |
206 |
136 |
14 |
698 |
425 |
1211 |
641 |
|
5 |
7.18 |
5640 |
3661 |
387 |
168 |
30 |
533 |
332 |
1298 |
759 |
|
6 |
7.22 |
4100 |
2664 |
212 |
145 |
35 |
458 |
136 |
1033 |
602 |
|
7 |
7.19 |
5670 |
3682 |
389 |
170 |
33 |
535 |
336 |
1402 |
761 |
|
8 |
7.20 |
2470 |
3296 |
188 |
72 |
5 |
251 |
412 |
1200 |
627 |
|
9 |
7.14 |
6720 |
4370 |
429 |
283 |
128 |
495 |
543 |
1608 |
811 |
|
10 |
7.15 |
6660 |
4324 |
424 |
278 |
120 |
490 |
538 |
1602 |
806 |
|
11 |
7.16 |
5680 |
3690 |
389 |
170 |
36 |
535 |
336 |
1404 |
761 |
|
12 |
7.17 |
5620 |
3645 |
338 |
172 |
26 |
601 |
508 |
1237 |
711 |
|
13 |
7.26 |
2970 |
1925 |
185 |
127 |
9 |
270 |
212 |
555 |
540 |
|
14 |
7.20 |
2680 |
1740 |
179 |
110 |
7 |
255 |
223 |
530 |
408 |
|
15 |
7.15 |
5150 |
3344 |
199 |
129 |
10 |
691 |
420 |
1211 |
634 |
|
16 |
7.18 |
3830 |
2486 |
249 |
138 |
4 |
367 |
488 |
619 |
584 |
|
17 |
7.24 |
3360 |
2182 |
192 |
103 |
12 |
364 |
380 |
690 |
406 |
|
18 |
7.20 |
3240 |
2102 |
181 |
92 |
12 |
352 |
369 |
674 |
392 |
|
Maximum |
7.26 |
6720 |
4370 |
429 |
283 |
128 |
708 |
543 |
1608 |
811 |
|
Minimum |
7.14 |
2470 |
1600 |
179 |
72 |
4 |
251 |
136 |
530 |
305 |
|
Average |
7.19 |
4645 |
3014.72 |
270.77 |
151.16 |
29.88 |
484.27 |
375.94 |
1042.38 |
613.05 |
The HCO3- and Cl- levels in the groundwater samples ranged from 136 to 543 mg/L and 305 to 811 mg/L, respectively (Table 3). The acceptable limit for HCO3- and Cl- in irrigation water is 250 mg/L [26]. Based on these acceptable levels, 0% of groundwater samples were suitable for HCO3-, 16% for Cl-, and 84% were not suitable.
4.2 Irrigation water quality assessment depends on pH
The term pH refers to a solution that is either acidic or alkaline. The acidity or basicity of irrigation water is measured by its pH, with a pH below 7.0 being acidic and above 7.0 being basic. The impact of pH on hydraulic conductivity, regardless of SAR, has been proven [30]. Typically, irrigation water has a pH range of 6.5–8.4 [31, 32]. Water with a low pH can be corrosive, while water with a high pH may cause scaling [33]. The pH values of the samples ranged from 7.14 to 7.26, with an average value of 7.19, falling within the typical ranges for irrigation water.
4.3 Irrigation water quality assessment depending on EC values
EC measures the capacity of a material or solution to carry an electric current. The electrical conductivity of groundwater increases as temperature rises and fluctuates with TDS concentration. EC is a valuable indicator of the risk of salinity in agriculture, as it mirrors TDS levels in groundwater. When EC rises, plants have limited access to water [34].
The EC of samples ranges from 2470 µS/cm to 6720 µS/cm, with an average value of 4645 µS/cm as shown in Table 3. According to the results in Table 4, all groundwater samples are classified as very high salinity and cannot be used for watering.
Table 4. EC classification of groundwater [35]
|
EC ms/cm |
Class Salinity |
Well No. |
% of Samples |
Remarks |
|
0-250 |
Low |
Nil |
Zero |
Safety for irrigation. |
|
250-750 |
Medium |
Nil |
Zero |
Can be used for moderate leaching. |
|
751-2250 |
High |
Nil |
Zero |
Can be used for irrigation with proper management. |
|
>2250 |
Very High |
1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18 |
100 % |
Cannot be utilized for irrigation. |
4.4 Irrigation water quality assessment depends on Total Dissolved Solid values
TDS refers to the solids remaining in a filtered water sample after evaporation. These solids include minerals, nutrients, and important ions such as Ca2+, Mg2+, K+, Na+, HCO3-, SO42-, Cl-, etc., found in natural water. TDS levels below 450 mg/l are ideal for irrigation, while levels between 450 and 2000 mg/l are considered moderate. TDS concentrations over 2000 mg/l are not suitable for agricultural purposes [36]. In the study area, groundwater samples had TDS levels ranging from 1600 mg/l to 4370 mg/l, with an average of 3014.72 mg/l. According to Carroll's (1962) classification shown in Table 5, the groundwater in the research area is considered brackish water.
Table 5. Groundwater Classification based on TDS Carroll's (1962) classification
|
TDS (mg/l) |
Classification |
Well No. |
% of Samples |
|
0-1000 |
Fresh water |
Nil |
Zero |
|
1000-10000 |
Brackish water |
1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18 |
100% |
|
10000-100000 |
Salty water |
Nil |
Zero |
|
> 100000 |
Brine |
Nil |
Zero |
4.5 Irrigation water quality assessment depends on SAR
Table 6. Water quality indexes
|
Well No. |
SAR (meq/l) |
Na% |
|
1 |
4.89 |
39.91 |
|
2 |
9.52 |
60.62 |
|
3 |
2.7 |
57.75 |
|
4 |
2.82 |
58.81 |
|
5 |
5.69 |
41.9 |
|
6 |
5.94 |
48 |
|
7 |
5.7 |
41.88 |
|
8 |
3.95 |
41.85 |
|
9 |
4.55 |
35.66 |
|
10 |
4.54 |
35.6 |
|
11 |
5.7 |
41.96 |
|
12 |
6.64 |
64.31 |
|
13 |
3.74 |
37.77 |
|
14 |
3.69 |
38.46 |
|
15 |
9.38 |
59.56 |
|
16 |
4.63 |
40.27 |
|
17 |
5.27 |
47.14 |
|
18 |
5.31 |
48.41 |
SAR is an important measure of groundwater quality for irrigation. High concentrations of sodium ions can reduce soil permeability, decrease water and air content, and disrupt soil structure by displacing calcium and magnesium ions. The SAR values of groundwater samples ranged from (2.7 to 9.52) meq/l as shown in Table 6. Based on the SAR classification in Table 7, all groundwater samples are classified as excellent and suitable for most crops and soil types, except those sensitive to sodium.
Table 7. Classification of groundwater samples based on sodium adsorption ratio SAR [37]
|
SAR (meq/l) |
Class of Water |
Well No. |
Percentage of Sample in the Study Area |
|
<10 |
Excellent |
1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18 |
100% |
|
10 to 18 |
Good |
Nil |
Zero |
|
10 to 26 |
Doubtful |
Nil |
Zero |
|
>26 |
Unsuitable |
Nil |
Zero |
4.6 Irrigation water quality assessment depends on %Na
Sodium is an essential ion for plant growth at low concentrations, but it can be toxic to crops at high concentrations. The recommended ranges for sodium ion concentration in irrigation water are as follows: below 20% (excellent), 20–40% (good), 40–60% (permissible), 60–80% (doubtful), and greater than 80% (unsuitable). In the present study, the percentage of sodium in the samples as shown in Table 6 ranged from 46.49% to 69.04%. According to Table 8, 28% of the groundwater samples are classified as good, while 61% are permissible, and 11% are doubtful.
Table 8. Classification of groundwater samples based on sodium adsorption ratio %Na [38]
|
%Na |
Class of Water |
Well No. |
Percentage of Sample in the Study Area |
|
<20 |
Excellent |
Nil |
Zero |
|
20 to 40 |
Good |
1, 9, 10, 13, 14 |
28% |
|
40 to 60 |
Permissible |
3, 4, 5, 6, 7, 8, 11, 15, 16, 17, 18 |
61% |
|
60 to 80 |
Doubtful |
2, 12 |
11% |
|
>80 |
Unsuitable |
Nil |
Zero |
4.7 Irrigation water quality assessment based on the Wilcox diagram
Based on the Wilcox diagram, 83% of water samples were classified as unsuitable for irrigation purposes, and 17% of water samples were classified as doubtful to unsuitable for crop irrigation as Figure 3.
Figure 3. Wilcox diagram to classify ground water quality for irrigation
4.8 Irrigation water quality assessment based on the USSL diagram
Based on Figure 4, the results show that 4 of the samples belong to the (C4S3) class, indicating very high saltiness with high sodium content. Additionally, 11 of the samples from the study region belong to the (C4S2) class, suggesting very high saltiness with medium sodium content. Furthermore, 3 of the samples in the study region are categorized under the (C4S1) class, indicating very high salinity with low sodium content. This implies that the samples are unsuitable for irrigation purposes.
4.9 The potential impact of high salinity and sodium levels on crop yield and soil health
The quality of water is significantly affected by the type and amount of dissolved salts present. Elevated levels of salt in irrigation water can lead to salt deposition in the root region, causing salinity issues and reducing the amount of water available for root absorption [39]. If the soil isn't flushed with low-salt water, the excessive levels of salt in irrigation water can avert plant growth and cause wilting [31]. Salinity damage is a very important aspect in choosing the satisfactory water used for crop watering as a result of its influence on the osmotic strain of the soil [40]. Soil permeability is primarily prompted by the aid of soil salinity and the SAR [41]. High ranges of sodium in water, can impact soil shape and texture. Sodium can disrupt soil aggregates and disperse first-class particles, leading to the clogging of soil pores [41]. The presence of sure ions which include sodium and chloride in high concentrations in irrigation water can result in toxicity issues in vegetation, resulting in reduced boom and output. The quantity of toxicity relies upon the plant range and its rate of absorption.
Figure 4. USSL diagram to classify Groundwater quality for irrigation
4.10 Comparison with similar studies
The permeability and water filtration in the soil are mainly influenced by salinity and SAR. In the study area, Table 3 shows a high EC value ranging between 2470-6720 µS/cm. These values are higher than those obtained by Hussain et al. [42] in their study of the groundwater of the Dammam aquifer in the western part of Iraq, which ranged between 1531-3460 µS/cm. The increased values EC is most likely owing to the study area's geological formations, which contain evaporated salts, gypsum, and dolomite. This deteriorates the water quality that travels through it. Table 6 reveals that SAR values in the research region were between (2.7-9.52) meq/l, which is consistent with the findings reported by Hussain et al. [42] in their investigation of groundwater in the Dammam aquifer in western Iraq, which ranged between (3.10 - 6.43) meq/l. These comparatively low results are the result of increased calcium and magnesium ion concentrations in the research region.
GIS is a specialized tool to generate spatial distribution maps that indicate acceptable and unsuitable zones based on water quality metrics [43]. This study created spatial distribution maps for EC, pH, TDS, SAR, and %Na.
Figure 5. Spatial distribution map of pH
The spatial distribution map of pH shown in Figure 5 indicates that each study area falls within the permissible limits for irrigation. It also shows that the largest part of the study area has a pH ranging from 7.16-7.20.
Figure 6. Spatial distribution map of EC
The spatial distribution map of EC is shown in Figure 6. This indicates that all study areas have high salinity. It also shows that the largest part of the study area has an EC ranging from 4001-5000 ms/cm.
The spatial distribution map shown in Figure 7 indicates that the TDS in the study area is very high. It also shows that the largest part of the study area has a TDS ranging from 2501-3000 mg/l, and the south part has a TDS ranging from 3501-4000 mg/l.
The spatial distribution map shown in Figure 8 indicates that the SAR in the study area is within the excellent zone. The values SAR ranges between (3.6–9.5) meq/l.
Figure 9 shows the geographical distribution map of %Na, which shows that the eastern half of the research region has very low %Na values when compared to the western sections of the study area.
Figure 7. Spatial distribution map of TDS
Figure 8. Spatial distribution map of SAR
Figure 9. Spatial distribution map of %Na
The use of groundwater is one of the strategic and main solutions in the desert and semi-desert regions such as the Western Desert in Iraq. The surface water quantities decrease significantly, particularly in times of water lack. The current study is a qualitative assessment of groundwater quality in the Al-Wafaa area in western Iraq. In this study, two diagrams were utilized to evaluate the quality of groundwater for irrigation. Below are the summary results of the assessment.
-The research found that most chemical standards exceeded permissible limits for irrigation. Na, Mg, Ca, and HCO3 ions exceeded acceptable levels for irrigation, while the chloride ions showed low suitability.
-pH values of the groundwater samples are within the normal levels for irrigation water.
-EC of the groundwater is very high salt, ranging from 2470 to 6720 (ms/cm), with an average of 4645. This suggests that samples are improper for watering and pose a health hazard.
-The high salinity levels may be due to the significant dissolution of rock minerals or ion exchange processes, which introduce chloride (Cl), sodium (Na), and bicarbonate (HCO3) ions into the groundwater in those specific areas. Further studies are required to evaluate the groundwater quality for different purposes.
-The water samples were classified as brackish water due to the values of TDS ranging from 1600 to 4370 mg/l, with a mean of 3014.72 mg/l.
-The Wilcox diagram indicates that most water samples are classified as unsuitable for irrigation, while few water samples are classified as doubtful to unsuitable.
-USSL diagram suggested that the groundwater samples belonged to C4S3, C4S2, and C4S1 categories, indicating high saltiness and high to medium to low sodium hazard. The findings show that the samples are not suitable for crop watering.
-This research recommends conducting multiple studies in the study area to assess the groundwater quality for drinking and domestic use.
-This research recommends conducting multiple studies in the research area to analyze heavy and toxic metals. It also suggests using geographic information systems and modeling techniques to rate the groundwater quality for watering.
-This research suggests growing salt-resistant plant species and utilizing modern scientific methods in irrigation operations.
-The findings of this study can assist policymakers in implementing measures to support sustainable agriculture in the research region.
-The proposed practical steps to address groundwater quality problems in the study area, especially high salinity and sodium levels, include the use of ion exchange filters and reverse osmosis filters. Additionally, chemicals such as sodium hydroxide or calcium hydroxide can be used to remove salts by reacting with them.
The authors are thankful to the University of Anbar College of Engineering – Dams and Water Resources Engineering Department and the general commission for Groundwater Department of Geology in Anbar for their support of this research as well as the people of the Al-Wafaa region who guided us to the sites of the wells water and helped us.
|
USSL |
United state salinity laboratory diagram |
|
EC |
Electrical conductivity |
|
WQI |
Water quality index |
|
SAR |
Sodium adsorption ratio |
|
RSC |
Residual sodium carbonate |
|
IQWI |
Irrigation water quality index |
|
ANN |
Artificial neural networks |
|
GPS |
Global positioning global |
|
%Na |
Percent sodium |
|
PNN |
Probabilistic neural network |
|
RBF-NN |
Radial basis neural network |
|
PI |
Permeability index |
|
KR |
Kelley ratio |
|
MHR |
Magnesium hazard ratio |
|
WHO |
World health organization |
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