Assessment and Data Assimilation of Agriultural
Drainage Water for Reuse in Irrigation Purposes
drainage water (ADW) represented an excellent source for irrigation purposes
where the water quality in terms of pH, dissolved oxygen (DO), Turbidity, total
dissolved solids (TDS), chemical oxygen demand (COD), nitrate (NO3-N),
ammonia (NH4-N), total suspended solids (TSS), volatile suspended
solids (VSS), total organic carbon (TOC), inorganic carbon (IC) and total
carbon (TC) along El-Salam canal were assessed. The results revealed that all
parameters were in accordance for reuse in agricultural purposes except
dissolved oxygen. This was mainly due to dumping of pollutants into the canal. The
COD was varied from 4.66 to 32.6 mg/l. This is mainly due to discharge of
domestic wastewater which cause a serious depletion of dissolved oxygen
(DO=3.98 mg/l). The NO3 was quite low and varied
from 0.49 to 1.89 mg/l while the ammonia concentration along the canal was
largely varied from 1.43 to 6.33 mg/l. This indicates that the nitrification
–denitrification could be occurred along the canal resulting a deterioration of
water quality along the canal. However, the ammonia and nitrate are represented
a good soil conditioner and minimizing the usage of chemical fertilizers. Relative (10 % and 40%) and constant
standard deviations (0.10 and 4) for the discharge were applied in the MIKE 11 data assimilation for pump
stations no. 1 and 2 which was not significant at T-test value (p>0.05).
Keywords— Data assimilation; Drainage water; El-salam canal; MIKE
11; Reuse; Water quality.
Egypt produces approximately 17 BCM/year
agricultural drainage water (ADW) which mainly discharge into Mediterranean Sea.
However, the ADW represents an excellent source for irrigation in Egypt.
Therefore, the Egyptian government proposed El-Salam Canal to irrigate 620,000
feddans to increase the economy of the country and minimize the depletion of
the water in the sea. So far, water scarcity is a serious problem in various
countries including Egypt 1. The ADW is suffered from different sources of
pollution i.e. domestic and industrial wastewater 2. The pollutants could
affect negatively on the water quality. Therefore, a mixing of Nile river and
ADW with a proper ratio is existing. However, the huge amounts of pollutants
deteriorate the water quality of the canal.
Agricultural drainage water (ADW) is an
alternative option for reuse creating an economic value for the country where
the nutrients are presented 3,4. Egypt established El-Salam Canal for reuse
with a capacity of 2.11 Billion Cubic Meters (BCM)/year of the Nile water and 1.905
BCM/year of water from Bahr hadous drain and 0.435 BCM/year of El-serw drain
5. The canal water is mainly used for
reclamation of 251,000 hectare of the desert located along the Mediterranean sea
of Egypt (90,000 hectare of which extend west of Suez Canal and about 161,000
hectares east of Suez Canal) 6. Unfortunately, El-salam Canal receives a
large amount of pollutants which cause a severe problems for the beneficiaries
and stalk holders. Some of treated wastewater is discharged and others without treatment
and drained into water bodies 7. Additionally, the water of El-salam Canal is
temporally facing a great challenge due to the shortage of water irrigation
from the Nile. Therefore, an assessment for the water quality along El-salam
canal for direct reuse in irrigation is urgently needed.
MIKE 11 is the most widely hydrodynamic
simulation software providing features of computational stability, high
accuracy and reliability. The model can be easily used for the detailed design,
management and operation of both simple and complex channel systems 8.
Furthermore, MIKE 11 data assimilation module in this study was applied to
identify the contributions of uncertainties associated with the water discharges
of the boundary source.
The El-Salam canal is the main water irrigation
source to Sinai Peninsula. The water is used to cultivate approximately 620,000
feddans. The canal is located in the Eastern North region of the Nile Delta,
with a total length of 88 km (Fig.1). The canal receives Nile fresh water from the
Damietta tributary of which situated at upstream of Fraskour Dam. The major
portion of agricultural drainage water (ADW) are
received from Fraskour, El-serw and Bahr hadous drains. The ratio of Nile water
and ADW was 1:1. This ratio provided total dissolved solids (TDS) of the mixed
water to be less than 1200 mg/l for irrigation according to Egyptian standards
for reuse 9, 10,
and 11. The
ADW supply sites for El-salam canal are from Fraskour drain at (1.80 km),
El-Serw drain at the (17.85 km) and Bahr Hadous drain at the (54.0 km) 12, Fig. 2.
Fig. 2. Schematic diagram of
sites and measurements
Water samples were collected from the intake of
the canal (0.00 km) and at eastward sites up to 88 km at Suez Canal, (Fig. 2). The
water were sampled from Damietta branch at 0.00 km (location 1), before and
after mixing with Faraskor drain (1.76 km -location 2) (1.92 km -location 3), at 14.40 km (location
4), before mixing with El-serw drain at 18.00 (location 5), after mixing with
El-serw drain at 18.44 km (location 6), at 48.00 km (location 7), before mixing
with Bahr hadous drain at 53.90 km (location 8), and after mixing with Bahr hadous drain at 54.55
km (location 9), at 68.75 km (location 10) and up to Suez Canal at 88.00 km
(location 11). Eleven representative water samples were monthly collected
during the spring season (from March to July 2017). Water samples were preserved
for physio-chemical analysis using 2 ml H2SO4 13.
The measured parameters
in situ were temperature of surface water and air, pH, turbidity, dissolved
oxygen (DO) and TDS. The measurements were by HQ30D portable multi meter.
A portion of samples were
transferred to the environmental laboratory of Egypt-Japan University for
Science and Technology (E-JUST) for analysis. The chemical oxygen demand (COD),
nitrate (NO3), ammonia (NH4-N), total suspended solids
(TSS), volatile suspended solids (VSS), total organic carbon (TOC), inorganic
carbon (IC), and total carbon (TC) was measured according to APHA (2005).
III. MIKE 11
MIKE 11 model was applied
to simulate the hydrodynamic and data assimilation of El-salam canal for water reuse.
It was initially developed by Danish Hydraulic Institute, for simulating flows,
water quality and sediment transport in rivers, estuaries and irrigation
systems 14. The MIKE 11 hydrodynamic (HD) is a one-dimensional, unsteady,
non-uniform flow simulation model describing the water motion by Saint-Venant
equations. The implicit finite difference six-point Abbott-Ionescu scheme is
adopted in pursuit of a solution 15
The data assimilation is a powerful tool for assessment
of the effect of uncertainties on the boundary conditions of the canal 2. The analysis was applied based on
MIKE 11 data assimilation (DA). Monte Carlo simulation was implemented to diffuse uncertainties from the
boundary conditions to the model outputs 16.
Statistical performance analysis was selected for the
assessment of the selected standard deviations (T-Test) for the comparison.
Fig. 3 shows the water
quality parameters (pH, DO, Turbidity, TDS, COD, NO3-N, NH4-N,
TSS, VSS, TOC, IC and TC) along El-Salam canal. The COD values were highly
fluctuated along the canal (Fig. 3). The COD was varied from 4.66 to 32.6 mg/l.
This is mainly due to discharge of domestic wastewater which cause a serious
depletion of dissolved oxygen (DO=3.98 mg/l). However, the COD values are
complying for reuse in limited irrigation purposes based Egyptian standards of
the drainage water in agricultural purposes 9 10
and Table 1.
Likely, TOC values were ranged from 1.96 to 8.97 mg/l, these results are comparable
to those obtained by Hafez 17. The pH
values ranged from 7.29 to 7.98 which is acceptable for reuse. An alkaline pH
value give undoubtedly indication on the algal growth. Moreover, the pH value could be increased due
to the release of carbon dioxide where the nitrifiers use it for ammonia oxidation.
The DO values ranged from 3.98 to 8.33 mg/l, which violated the allowable limit
mg/l). This could be attributed to the negative impact of the pollution of
El-Serw and Bahr Hadous drains which receives a significant amount of domestic wastewater
18. The most of oxygen is mainly consumed due to
the degradation of organic matter. The TDS values were highly fluctuated from 288.5
to 1094.5 mg/l resulting an average value of 528 mg/l, which complied for reuse
(<1200 mg/l). The high values of TDS was mainly due to the seepage of salty water from El-Manzala Lake which increased the salinity of the canal. The NO3 was quite low and varied from 0.49 to 1.89 mg/l while the ammonia concentration along the canal was largely varied from 1.43 to 6.33 mg/l. This indicates that the nitrification –denitrification could be occurred along the canal resulting a deterioration of water quality along the canal. However, the ammonia and nitrate are represented a good soil conditioner and minimizing the usage of chemical fertilizers. The water of the canal was mainly turbid (3.7-32.41 NTU) due to the presence of suspended solids which affect negatively on the quality where TSS values ranged from 11.15 to 42.85 mg/l. the TSS values are complying for reuse however, the precipitation of coarse suspended would be accumulated in the canal causing serious problems such as anaerobic condition in the bottom. Moreover, a high turbidity would reduce the penetration of oxygen from the air to the water resulting a low dissolved oxygen. Based on these results, the water quality of El-salam canal is reasonable for direct reuse for irrigation according to the Egyptian standards. TABLE I. the measured water quality parameters along El-salam canal and the Egyptian standards for reuse of ADW in irrigation. parameters range average Law 48/1982 Standards Water temp. (°C) 22.40 – 25.60 23.30 5 above prevailing T pH value 7.29 – 7.98 7.68 6.5 – 8.5 DO (mg/l) 3.98 – 8.33 5.80 > 5
3.70 – 32.41
288.50 – 1094.50
4.66 – 32.59
0.49 – 1.89
0 - 10
1.43 – 6.33
0 - 5
11.15 – 42.85
4.00 – 15.50
1.96 – 8.97
17.24 – 50.78
22.62 – 58.34
*NA, not available.
Fig. 3. Water quality parameters distribution
along El-Salam canal.
B. MIKE 11
The HD model calibration and validation were performed
for two years' data (2012-2014) previously described by Assar 19. The model successfully
proved its reliability to simulate the water quantity along the canal. The discharge inflow for the intake
boundary of El-salam canal was assumed to be inaccurate using DA module. Different
values of relative (10 % & 40%) and constant (0.10 & 4.0) standard
deviations for the discharge were applied to estimate the uncertainty of model prediction
outputs. Two locations namely pump stations no. 1 and 2 at 22.0 and 53.0 km
were selected for analysis their results in terms of the relative and constant
The comparison between the observation and
the predicted discharges data at pump station no.1 for the relative standard
deviations of 10 and 40 % were not significant at T- values of 0.06 (p>0.05) and 0.07 (p>0.05), respectively. Furthermore,
at pump station no.2 the comparison between the observation and the predicted
discharges for the relative standard deviations of 10 and 40 % were not
significant where T-test values were 0.66 (p>0.05) and 0.38 (p>0.05),
respectively. Moreover, the T- value for the prediction of SD of 10 and 40 %
was not significant at pump station No.1 and 2, where T-test values were 0.01
(p>0.05) and 0.00 (p>0.05) respectively, Figs. 4 & 5.
Fig. 6 shows there no significant results
for pump station 1 and 2 for the constant standard deviations of 0.10. The
T-test values were 0.08 (p>0.05) for pump station 1 and 0.68 (p>0.05) for
pump station 2. Fig. 7 displayed the results for pump station 1 and for the
constant standard deviation of 4.0 was not significant at T-test values of 0.07
(p>0.05) for pump station 1 and 0.68 (p>0.05) for pump station 2. The
T-values the prediction of SD of 0.1and 4.0 was not significant at pump station
No.1 and 2, where T-test values were 0.01 (p>0.05) and 0.00 (p>0.05)
Fig. 4. The observed and predicted
discharge data for SD 10% at pump station no. 1 (a) and 2 (b) of El-salam canal
for the period (October 2013 – July 2014).
Fig. 5. The observed and predicted
discharge data for SD 40% at pump station no. 1 (a) and 2 (b) of El-salam canal
for the period (October 2013 – July 2014).
Fig. 6. The observed and predicted
discharge data for SD 0.10 at pump station no. 1 (a) and 2 (b) of El-salam
canal for the period (October 2013 – July 2014).
Fig. 7. The observed and predicted
discharge data for SD 4.0 at pump station no. 1 (a) and 2 (b) of El-salam canal
for the period (October 2013 – July 2014).
quality parameters of El-Salam canal in terms of organics and nitrogen
compounds is reasonable for direct reuse in irrigation purposes in the areas
suffering from lack of water resources. Moreover, the current mixing ratio
between the ADW and the Nile fresh water (1:1) is quite sufficient to produce
an acceptable water quality. A shortage of the Nile water supply to El-Salam
canal would seriously effect on the quality and accordingly needs a proper
treatment process. Relative (10
% and 40%) and constant standard deviations (0.10 and 4.0) for
the discharge were applied for pump stations no. 1 and 2 which was not