الفهرس 
ACKNOWLEDGMENTSOnly 14 pages are availabe for public view
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Abstract
Southern Wadi Qena area extends between latitudes 26° 05’ and 26° 50’ N, and longitudes 32° 35’ and 33° 10’ is considered one of the most promising area in what’s called theʺ Golden Triangle ʺ in Eastern desert of Egypt. This is because it has natural resources (groundwater, soil, building material) infrastructural, and nearest to the Qena city. The highway that crossing the area is the main link between Qena, Sohag, Assuit, Luxor, and Red Sea Governorates. The dominant climate prevailing the area is a dry climate, with long hot summers and short warm winters.
The geology and geomorphology of the southern Wadi Qena are mostly covered by sedimentary rocks. Southern Wadi Qena is composed of Red Sea highland (basement rocks), a plateau of Cretaceous /Lower Tertiary Sedimentary sequence (Nubian sandstone, Qusier Shale,Duwi formation, Dkhala Shale, Tarwan Chalk, Esna Shale and Thebes formation) and Pliocene/ Pleistocene deposits with undivided Quaternary deposits that represents the most suitable area for the reclamation activities .
The area is covered by two aquifers, including Quaternary aquifer (shallow and deep aquifers) and Nubian sandstone aquifer.
The main objectives of this study is to investigate the quality of groundwater and the status of soil under the southern part of Wadi Qena conditions. The specific objectives of the study were:
1. To assess the chemical analysis of groundwaters of southern part Wadi Qena as well as to classify these waters according the standard suitability classes of irrigation water.
2. To study impacts of groundwater quality for drinking and domestic uses.
3. To study impacts of groundwater quality on soil properties.
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A total 24 groundwater samples (12 Quaternary aquifer samples, 4 Nubian sandstone aquifer samples and 8 shallow pits samples) were collected from different wells located in southern Wadi Qena. These wells are used for irrigation purposes.
from the area that the wells covered, two composite samples were collected one from the surface soil (0-30 cm) and the other from the subsurface soil (30-60 cm). A total of 48 soil samples were collected from the cultivated soil. Also, one composite sample was collected from 0 to 60 cm depth from uncultivated soil. All sampling points were geo-referenced and sampling dates were recorded by GPS.
The results of this study can be summarized as follow:
Groundwater chemistry and Quality for irrigation
Groundwater pH
Groundwater pH in southern Wadi Qena ranged from 6.70 to 8.09. The pH values of Quaternary aquifer samples range from 7.17 to 8.09 and 6.75 to 7.78 in shallow Quaternary groundwater. The pH values of Nubian sandstone aquifer samples range from 6.70 to 8.08 that indicate slightly alkaline nature of water.
Groundwater Electrical conductivity (ECw)
The ECw values fluctuated from 1740 to 15710 μS cm-1. The ECw of Shallow Quaternary aquifers samples range from 4690 to 15710 μS cm-1, 1740 to 7510 μS cm-1 in deep Quaternary aquifer and 2000 to 2720 μS cm-1 in Nubian sandstone aquifer. About 12.5 % of the collected groundwater samples fall in the third class of the high salinity hazard. Meanwhile, 87.5% of these samples showed a very high salinity hazard.
Total Dissolved Solids
The total dissolved solids (TDS) of the groundwater samples ranged from 1114 to 10054 with an average of 3659 mg/l. In a shallow pits, the total
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dissolved solids of groundwater samples ranged from 3062 to 10054 mg/l with an average value of 6560 mg/l. In a Quaternary aquifer, the TDS ranges from 1114 to 4806 mg/l with an average value 2439 mg/l, the TDS of the Nubian sandstone aquifer ranges from 1280 to 1741 mg/l with an average 1514 mg/l.
Soluble Cations
- In south Qena, sodium concentrations in shallow Quaternary aquifer ranges from 305.20 to 820.05 mg/l. In Nubian aquifer sodium concentrations of collected sample range from 283.22 to 512.37 mg/l. The lowest values of groundwater were found in Nubian aquifer, while the highest Na values were found in Shallow Quaternary aquifer. All of groundwater aquifers in the study area had restriction on the use of water for irrigation purpose, where the sodium concentration is basically more than 70 mg/l.
- Potassium concentration (K+) of collected groundwater samples in shallow Quaternary aquifer ranges from 6.36 to 28.89 mg/l and in deep Quaternary aquifer is 2.03 to 11.08 mg/l. It’s value in Nubian aquifer is 2.80 to 6.21 mg/l. The highest values of K concentration were found in shallow pits, while the minimum one found in Nubian and deep Quaternary aquifer. All of groundwater aquifers are containing K greater than 2 mg/l.
- Calcium concentration of groundwater aquifer samples ranged from 80.14 to 2235.91 mg/l. Calcium concentration of collected groundwater samples in Shallow Quaternary aquifer ranges from 801.40 to 2235.91 mg/l and in deep Quaternary aquifer is 80.14 to 857.50 mg/l. In Nubian aquifer, Ca concentrations of collected samples range from 108.19 to 280.49 mg/l. The most groundwater aquifers (87.5%) are containg Calcium greater than 120 mg/l (FAO, 1994). Only 3 groundwater have
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Ca concentration less than 120 mg/l (2 samples in Quaternary aquifer and one sample in Nubian aquifer.
- Magnesium concentrations the studied groundwater samples ranged from 14.58 to 1020.60 mg/. Magnesium concentrations of collected groundwater samples range from 184.68 to 1020.60 mg/l in shallow Quaternary aquifer, in deep Quaternary aquifer are from 34.02 to 442.26 mg/l. The Nubian aquifer is 14.58 to 106.92 mg/l. The minimum values recorded in Nubian sandstone aquifer wells, while the highest values were found in water of shallow pits. 83.33% of groundwater samples have Mg content higher than FAO (1994) limit (50 mg/l), whereas, about 16.67% of groundwater samples have lower than FAO (1994) limit.
Soluble Anions
- Bicarbonate values in groundwater samples vary from 88 to 271mg/l. The value of bicarbonate is from 87.89 to 197.96 in Shallow Quaternary aquifer, in deep Quaternary aquifer are from 92.87 to 271.28. The Nubian aquifer is 127.09 to 256.62 mg/l. The lowest values of HCO3- were recorded by water in Shallow pits and deep Quaternary. Whereas, the highest one was found in Nubian sandstone aquifer. All the groundwater samples have bicarbonate levels lower than FAO upper limit (HCO3 >520mg/l).
- Sulphate concentration ranges from 165.14 to 3236.66 mg/l. The Sulfate value ranges from 165.14 to 1973.97 mg/l. in Quaternary aquifer. In Nubian aquifer, its value ranges from 228.72 to 400.74 mg/l. Meanwhile in shallow aquifer sulphate concentrations of collected samples range from 934.09 to 3236.66 mg/l. Based on the previous classification, about 66.67% of groundwater samples have SO4-2 more than 600 mg/l. This means that these waters can be not used for irrigation. Most of the
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groundwater (95.83% of study area) is bad for the infrastructures against the corrosion effect. They concentrations of more than 200 mg/l.
- Chloride content in the groundwater samples ranged between 389.95 and 4608.50 mg/l. The chloride concentration ranges from 389.95 to 1843.40 mg/l in Quaternary aquifer, but Nubian aquifer, its value is 496.30 to 709.00 mg/l. Meanwhile, chloride concentrations of collected samples in shallow Quaternary aquifer ranges from 1176.94 to 4608.50 mg/l. All the groundwater samples have chloride levels more than FAO (1994) upper limit (Cl -) 355 mg/l). This means that these waters are unsafe for almost all types of plants are dangerous for sensitive, moderate and tolerant crops. This groundwater has negative effect on moderately tolerant plants.
Sodium Adsorption Ratio (SAR)
The Sodium adsorption ratio (SAR) values of the groundwater samples in the studied area varied from 4.46 to 14.17 with an average of 8.67. The SAR values ranged between 5.15 to 12.89 in Quaternary aquifer groundwater samples, but in Nubian aquifer, its value is 5.16 to 13.09. Meanwhile, SAR values of collected samples in shallow Quaternary aquifer ranges from 4.46 to 14.17. About 62.5% of the groundwater samples have SAR values less than 10, while 37.5% of groundwater in the study area have SAR values ranges between 10-18. The low SAR value result from the dominant Calcium in the water samples. Based on USSL (1954) the water samples of the study area classified into S1 and S2. It is clear 62.5 % of the total groundwater samples fall under S1 i.e. low sodium hazard, while, the groundwaters in the remaining area (37.5 %) occurs S2 category indicating medium Na hazard.
Soluble sodium percentage (SSP)
Soluble Sodium percentage values ranged between 37.20 and 83.21 % with an average of 56.22 %. The soluble sodium percentage values in shallow
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Quaternary aquifer ranges from 37.20 to 57.21 %, deep Quaternary aquifer 44.58 to 83.21 %. In Nubian sandstone aquifer, SSP values of collected sample range from 52.15 to 82.58%.
About 12.50, 16.67 and 70.83% of the investigated groundwater samples (24 samples) have permissible to doubtful, doubtful to unsuitable and unsuitable irrigation water qualities, respectively. It means most of these samples are unsuitable for irrigation
The ECw and SAR Diagram of the studied groundwater samples in South Wadi Qena
It clear that 15 groundwater samples (62.5%) fall under C4S1 category suggesting low sodium and very high salinity hazards conditions. Moreover, 3 samples (12.5%) occurs in the C3S2 category indicating medium sodium and high salinity hazards and only 6 samples (25%) take place in the C4S2 type suggesting medium sodium and very high salinity hazards.
About 70.83 % of these waters (17 samples) showed very low quality (unsuitability). Meanwhile the rest samples (12.5, 16.67%) showed a low quality (permissible to doubtful, doubtful to unsuitability), respectively.
Residual Sodium carbonate (RSC)
Residual sodium carbonate values ranged between -96.36 and 1.04 (well nos.19 and 9) in Sallow and Quaternary groundwater samples, respectively. The calculated values range from -96.63 to 26.24 meq/l in Sallow Quaternary aquifer, and from -37.12 to 1.04 meq/l in deep Quaternary aquifer, and from -9.00 to -0.18 meq/l in Nubian aquifer. So, groundwater samples analysis showed that RSC of all samples within the safe quality category for irrigation.
Corrosivity Ratio (CR)
Corrosivity ratio values fluctuated from 1.43 to 54.04 with an average 11.91. Corrosivity ratio values from 9.21 to 54.04 in shallow aquifer, and from
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1.43 to 14.63 in deep Quaternary groundwater samples and from 2.39 to 4.90 in Nubian aquifer. Nubian aquifer gave the lowest values CR, While the highest one of CR were found for shallow aquifer.
Chloro–Alkaline Index (CAI)
Chloro- alkaline index values from -0.28 to 0.52 with an average of 0.20. It values varies from 0.27 to 0.52 in Shallow aquifer, and -0.28 to 0.41 in deep Quaternary aquifer, and from -0.22 to 0.24 in Nubian aquifer. It is obvious that about 75% of groundwater samples gave negative values of CAI, while 25% of samples displayed negative values. This indicates that partially exchange between Na+K in the groundwater with Ca+Mg in the host rock concentrated in 75% of the study area. on the contrary, the exchange between Ca+Mg in the groundwater with Na + K in the host rock covers about 25% of study area aquifer.
Magnesium Ratio (MR)
Magnesium ratio (MR) of the studied groundwater samples varies from 10.71 to 48.28 with an average of 33.48.In Quaternary aquifer ranged from 25.33 to 45.96 with an average 36.62, but in shallow aquifer varied from 17.54 to 42.94 with an average of 30.17.Meanwhile , it ranged from 10.71to 48.28 with an average of 30.65. All of Groundwater samples (100%) showed lower than permissible limit (MR<50). This means that all groundwaters in study area have not magnesium hazard.
Permeability Index (PI)
The permeability index of the groundwater in the study area varied from 39.38 to 92.87 with an average of 60.41. In Quaternary aquifer varies from 47.78 to 92.87 with an average of 62.43, and from 39.38 to 58.24 with an average 47.84 in shallow aquifer samples, but in Nubian aquifer ranged between 58.47 to 91.50 with an average of 79.49. Based on permeability index, 4.17% of
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the groundwater samples are good ( PI<40), 75% are injurious (PI =40 -80) and 20.83% are unsatisfactory (PI more than 80) according to Deneen’s guideline.
Kelley’s Ratio (KR)
Kelley’s ratio (KR) ranged from 0.59 to 4.94 with an average of 1.70. In Quaternary aquifer; KR value varies from 0.80 to 4.94 with an average of 1.76, and 1.08 to 4.72 with an average of 3.16 in Nubian aquifer, meanwhile, it ranged from 0.59 to 1.33 with an average of 0.88 in the shallow aquifer. The lowest value of KR was observed in shallow aquifer, whereas the highest one was recorded in Nubian and Quaternary aquifers. About 37.5% of groundwater samples are suitable, while 62.5% of samples are unsuitable for irrigation.
Potential Salinity (PS)
The potential salinity of studied groundwater samples ranged from 11.86 to 142.81 with an average of 48.14. In Quaternary aquifer varied between 11.86 and 62.27 with an average 31.17, and from 39.06 to 142.8 with an average of 88.46 in sallow aquifer. Meanwhile, it ranged from 15.19 to 21.75 with an average 18.42 in Nubian aquifer groundwater samples. The highest values of PS were found in shallow aquifer waters, whereas the lowest one was recorded in Nubian aquifer groundwater samples. Based on Hwang et al. (2017) classification, all groundwater samples (100%) have injurious to unsatisfactory water, which can be used for irrigation under medium to high permeability soils.
Effect of Well Depth on Groundwater chemistry
Correlation analysis reveals that positive and high significant (P ≥ 0.01) correlation is detected between well depth and groundwater pH with correlation of 0.296. This mean that pH of groundwater is increasing due to the increase of well depth.
There was negative correlation between well depth and ECw, Na, K, Ca, Mg, Cl, SO4 with significant correlation coefficient of -0.697, -0.599, -0.599, -
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0.773, -0.577, 0.664, and-0.756, respectively. But there was positive correlation between well depth and HCO3.
Data also reveal that increasing well depth caused a reduction in the studied parameters.
Effect of irrigation with groundwater on chemical soil properties:
Soil Salinity (ECe)
Generally, in most locations, ECe values ranged from 1.60 to 271.59 dS/m. In addition, the surface layer was more saline than subsurface layer. The salinity of the studied soils significantly increased with increasing the salinity of groundwaters.
There are relationship between ECe and ECw as well as Na, K, Ca, Mg, Cl, HCO3 and SO4 of groundwaters and chemical properties of these soils irrigated with these waters.
Soil pH
The pH values in the surface cultivated soil samples ranged from 7.26 to 8.48 with an average value of 7.81. Meanwhile, the pH values in the subsurface cultivated soil samples ringed from 7.36 to 8.40 with an average value of 7.88. There are non significant positive correlation (r=0.136) between soil pH values and pH values in irrigation water and non significant negative correlation (r = -0.295) between soil pH values and ECe values in surface soil sample.
Sodium adsorption ratio (SARe)
Sodium adsorption ratio (SARe) values in the surface soil samples ranged from 1.74 to 57.49 with an average of 11.54. While, the values of SARe in subsurface soil samples between 0.60 to 29.86 with an average of 5.70.
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Whereas, it ranged from 0.25 to 43.19 with an average value of 8.16 in the uncultivated soil samples (0-60 cm depth). Non significant positive correlation between the sodium adsorption ratio (SARe) of the saturated soil paste extract and ECw, SARw and soluble sodium concentration in irrigation water (r = 0. 396 and 0. 0.106) respectively.
Soluble cations:
Soluble Sodium (Na+)
In most locations of the studied surface sample , soluble Na+ concentration were more than 20 mmol/l , we observed 54.17% of locations have soluble sodium concentration in surface soil samples more than 20 mmol/l , while about 29.17% of locations in the subsurface soil samples have soluble sodium concentration more than 20 mmol/l .
The data found that a significant positive correlation between the soluble sodium concentration of the saturated soil paste extract and ECw of groundwater ( r =0.508* ) and non significant positive correlation between the soluble sodium concentration of the saturated soil paste extract in surface soil sample and SARw and sodium concentration in irrigation with groundwater ( r = 0..031 and 0. 369 ,respectively).
Soluble potassium (K+)
Generally, among all soluble cations, the soluble K+ has the lowest values. In most locations, Soluble K+ has the decreased with depth. This coincides well with the ECe value.
Soluble Calcium (ca2+)
The highest value of soluble Ca2+ concentration was found in the reclaimed or desert soil in spite of the soil in this area having sand or sandy loam texture. This could be attributed to the increase in the saline of groundwater in this
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location’s comparison with another locations as well as dissolution of the limestone Plateau near this area.
Soluble Magnesium (Mg2+)
The data showed that soluble Mg2+ concentration increase with increasing Mg2+ concentration in the irrigation with groundwater. High Significant positive correlation was found the soluble Mg2+ concentration of the saturated soil paste extract and Mg2+ in irrigation with the groundwater (r = 0.574**) Table (20). In addition, positive correlation was found between the soluble Mg2+ concentration in the saturated soil paste extract and ECw of irrigation with the ground water (r =0.401).
Soluble Anions
Soluble Chloride (Cl-)
There is positive correlation between the soluble Cl- concentration in the saturated soil extract and ECw of irrigation with the groundwater (r =0.505*). In addition, soluble Cl- concentration increase with increasing Cl- concentrations in the irrigation with the groundwater. Significant positive correlation was found between the soluble Cl- concentration of the saturated soil past extract and Cl- concentration in irrigation with groundwater (r= 0.540 **).
Soluble Sulphate (SO42-)
The non significant positive correlation was found between the soluble SO42- concentration in the saturated soil paste extract and ECw of irrigation with the groundwater (r = 0.077). Moreover, the significant positive correlation was found between the soluble SO42- concentration in the saturated soil paste extract and SO42- concentration in irrigation water with the groundwater (r = 0.092).
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Soluble bicarbonate (HCO3-)
In the surface of the cultivated soil samples, soluble bicarbonate was less than 10 mmol/100gs, while the concentration of bicarbonate (HCO3-) in the subsurface of the cultivated soil samples, it ranged from 0.76 to 1.92 mmol/l with an average value of 1.39 mmol/l. In most farms (locations, in the subsurface soil samples, the concentration of bicarbonate was less than 10 mmol/l (100 % of total studied area). However, the concentration of soluble bicarbonate (HCO3-) in the studied of uncultivated soil sample (0-60 cm depth) have bicarbonate ranged between 1.04 and 3.88 mmol/l with an average value of 1.64 mmol/l, and it was found that 100% of samples less than 10 mmol/l.
The groundwater quality for drinking purposes was evaluated by comparing its hydrochemical values to the World Health Organization (2004) and Egyptian standards for drinking water (EHCW, 1995). This comparison found that all groundwater samples of the study area are not acceptable for drinking purposes.
The recommendation from this study
Finally, it can be recommended that the assessment of groundwater and soil qualities is necessary to choice the suitable management practices for the soil and groundwater of wadi Qena as well as exigency for periodic analysis of soil and groundwater wells to determine the change taking place in the salinity.
Also, bradding a data base of soil properties and groundwater quality for soils of Wadi Qena and generally for Eastern desert and update it continuously. It was be useful for sustainable, development and monitoring the degradation of soils. Also, cultivating and selecting the appropriate crops, which are resistance to salinity, especially in the areas suffer from the problem of increasing salinity.
References