The Hydrography of the Suez Canal
51
hoped that more data on the past periods in the evolution of the Canal system
may still be available and awaiting publication. As it stands now, the picture of
the distribution and dynamics of the hydrographical parameters in the Canal,
over the seasons and during its 106 years of existence, is fragmentary.
Therefore, in tbis field of easily measurable facts, hypothetical assumptions
still prevail. A few of these, in more or less bistorical order are:
1. The hypothesis that the Canal waters were originally less saline and that it
took several years until they reached their high salinities.
2. The hypothesis of the silting up of the Canal, unless permanently dredged.
3. The belief that the high salinity of the Bitter Lake is due only to the
dissolution of the bottom layer of salt and that tbis lake will eventually reach
normal sea water salinities.
4. The belief that the high salinities measured in the northern Gulf of Suez
result from an outflow ofBitter Lake water.
5. The much repeated assumption that the minimum temperatures decrease
from the Gulf of Suez, northward through the Canal.
6. The assumption that there are throughgoing currents through the whole of
the Canal system.
7. The role ascribed to the Nile floods in generating the seasonal North-South
current in the northern Canal section.
8. The belief that there are seasons in the Canal which are especially propitious to the migration of animals through it.
The Currents. There are few measurements of the currents in the Canal. Fox
(1926) stated that up until that time the Canal Company had never made a
systematic study of the currents, because of the regularity of the tidal currents in
the southern Canal and the dependence on the permanent current in the northern
section.
Much of what is given in literature about "currents" is based on salinity
differences measured at different periods ofthe year, while changes in the horizontal and vertical value distribution were interpreted as indicative of water mass
movements (Wüst, 1935; Morcos, 1960). If temperature is not taken into account,
this assumption is very much weakened. The first author to give temperaturej
salinity relation (TjS) diagrams and density calculations, is EI Sabh (1969).
The old data about displacement of water masses in the Canal were based on
the assumption that the only source for the highly saline water body was in the
depth layer of the Bitter Lake. The possibility of an increase due to evaporation in
density in the shallow lagoons surrounding the Bitter Lake and Lake Timsah has
not been taken into account. However, it is now evident (see below) that with
maximum salinities in the Canal system being around 45%0, as at present, eva porative processes clearly prevail over dissolution processes-if they still occur at
all.
Three basic vectors influence the currents ofthe Suez Canal: (1) the water level
differences between the Gulf of Suez and the Mediterranean at Port Said, with the
addition of the evaporative level decrease in the lakes of the Canal; (2) the direction and the strength of the tidal waves; and (3) the direction and strength of the
winds.
51
hoped that more data on the past periods in the evolution of the Canal system
may still be available and awaiting publication. As it stands now, the picture of
the distribution and dynamics of the hydrographical parameters in the Canal,
over the seasons and during its 106 years of existence, is fragmentary.
Therefore, in tbis field of easily measurable facts, hypothetical assumptions
still prevail. A few of these, in more or less bistorical order are:
1. The hypothesis that the Canal waters were originally less saline and that it
took several years until they reached their high salinities.
2. The hypothesis of the silting up of the Canal, unless permanently dredged.
3. The belief that the high salinity of the Bitter Lake is due only to the
dissolution of the bottom layer of salt and that tbis lake will eventually reach
normal sea water salinities.
4. The belief that the high salinities measured in the northern Gulf of Suez
result from an outflow ofBitter Lake water.
5. The much repeated assumption that the minimum temperatures decrease
from the Gulf of Suez, northward through the Canal.
6. The assumption that there are throughgoing currents through the whole of
the Canal system.
7. The role ascribed to the Nile floods in generating the seasonal North-South
current in the northern Canal section.
8. The belief that there are seasons in the Canal which are especially propitious to the migration of animals through it.
The Currents. There are few measurements of the currents in the Canal. Fox
(1926) stated that up until that time the Canal Company had never made a
systematic study of the currents, because of the regularity of the tidal currents in
the southern Canal and the dependence on the permanent current in the northern
section.
Much of what is given in literature about "currents" is based on salinity
differences measured at different periods ofthe year, while changes in the horizontal and vertical value distribution were interpreted as indicative of water mass
movements (Wüst, 1935; Morcos, 1960). If temperature is not taken into account,
this assumption is very much weakened. The first author to give temperaturej
salinity relation (TjS) diagrams and density calculations, is EI Sabh (1969).
The old data about displacement of water masses in the Canal were based on
the assumption that the only source for the highly saline water body was in the
depth layer of the Bitter Lake. The possibility of an increase due to evaporation in
density in the shallow lagoons surrounding the Bitter Lake and Lake Timsah has
not been taken into account. However, it is now evident (see below) that with
maximum salinities in the Canal system being around 45%0, as at present, eva porative processes clearly prevail over dissolution processes-if they still occur at
all.
Three basic vectors influence the currents ofthe Suez Canal: (1) the water level
differences between the Gulf of Suez and the Mediterranean at Port Said, with the
addition of the evaporative level decrease in the lakes of the Canal; (2) the direction and the strength of the tidal waves; and (3) the direction and strength of the
winds.