| Abstract: |
The main conclusions drawn from the study carried out on the zone of mixing water between Blad EL Ayed drain and Wadi EL Sharky canal can summarized as follows:1- In Egypt, due to lack of integrated management, the drainage water reuse scheme are mostly operated based on the drainage water availability and the water demand downstream the mixing location. Blad EL- Ayed reuse scheme is selected to present how the appropriate mixing ratio can be defined.2- To identify the water quality characteristics of Blad EL Ayed reuse scheme, a monitoring program has been designed and carried out for three sites; before and after mixing sites at EL Wadi Sharky canal and the reused drainage water from Blad EL Ayed drain. The number of samples per year giving the appropriate design frequency is 12 samples while the mixing is estimated by 3.0 km along EL Wadi canal after the mixing point.3- Water quality assessment using the data generated from the monitoring program shows that there is no restriction on use the fresh water while there is a slight to moderate degree of restriction on the use of drainage water and mixing water. The water salinity for all sites is very satisfactory for livestock. Moreover, at any rate, the concentrations of the heavy metals for fresh, drainage and mixing water do not reach the value that could cause problems to soil or plants.4- To define the appropriate mixing ratio between fresh water of Wadi Sharky canal and Blad EL Ayed drain, a simple mass balance model using a spreadsheet macro-program for the load is developed. This model is applied for EC, TDS, Na and SAR for each month as a time step. Considering the maximum allowable limit for each of the water quality variables, mixing ratio can be defined.5- The mixing ratio for EC ~s very close to the TDS and has the same trend.The appropriate mixing ratio varies between ( 2.3 : 1 ) to ( 3.3 : 1 ) and the average is ( 2.9 : 1).6- The mixing ratio for Na is varied in wide range relative to the ones of the EC and TDS although they have the same trend. The appropriate mixing ratio for Na varies between ( 1.3 : 1 ) to ( 2.9 : 1 ) and the average ( 2.1 : 1 ) while no measures are needed for control the mixing ratio for infiltration rate problem .. 7- For operational management reason, a smooth ratio IS recommended which is varied between (3.5 : 1 ) to ( 3.1 : 1 ).8- No significant influences of trace elements from agricultural drainage water on the quality of fresh irrigation water.9- The estimated mixing ratio can be used to detect the number of hours of pump station working, in case of reuse of drainage water to mix with fresh irrigation water.It is recommended to considering the following before starting any drainage reuse project:1- The need to generally increase the efficiency of water use in agriculture, municipalities and industry. Improved efficiency in agricultural water use is required both to maintain productivity growth and to allow the reallocation of water from agriculture in the old lands to urban and industrial uses, as well as to new land developments2- The quality of Egypt’s restricted land and water resources must be sustained in the face of mounting pressure to degrade these resources through water-logging, salinization, groundwater mining, and water pollution.3- Pollution of water from industrial effluents, poorly treated sewage, and runoff of agricultural chemicals is a growing problem in Egypt and a challenge to all Egyptians. Fresh water is in Egypt a scarce resource, it is too valuable to be made unusable by pollution. It is too valuable to be used to dispose of wastes.
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