The Sirbonic Lagoon (Sabkhat el Bardawil)
35
openings respectively designated as Boghaz 1 and Boghaz 2 are marked on the
map in Figure 12.
It seems that before 1927 the whole basin was a "Sabkha" (meaning in Arabic
a "salt swamp"). During the winter storms, the gales flooded the swamp (as they
do today) and towards the summer the whole area or the majority of it evaporated and turned into a "playa". Before the building of the Suez Canal, which cuts
through Lake Menzaleh between two earthen banks, the waters of this lake
probably communicated at high Nile floods with the Sirbonis. It can be presumed
that the basin became areal lagoon several times during the centuries, carrying
water all the year round. It is of interest to give at some length the references of
Strabo (1st Century of Christian Era) to the Sirbonis. In his words "when the sea
retired, these regions (northern Egypt, author's note) remained bare except that
the Lake Sirbonis remained; then the lake also broke through to the sea and thus
became a bog" (1, 50). In V olume XVI, 760, Strabo gives the dimensions of the
lake: 200 stadia in length and 60 stadia maximum breadth, i.e. some 34 km by 11
km, one-third of the present length and half of the present maximum width. The
lake communicated with the sea through an opening called Ecregma ("the outbreak") somewhat east of Mons Cassius. But in Strabo's time "the Ecregma has
become filled up with earth". At the time of Plinius, about half a century after
Strabo, the "Sirbonis Lacus" was already a medium-sized marsh lake ["nunc est
palus modica" (5, 68)]. Both Strabo and Diodorus of Sicily reported occasional
gales invading the Sirbonis from the sea.
On several old maps such as the 15th Century Weimar map, the 16th Century
map of Tileman Stella and the 18th Century map of Tirion and Loveringh in
Amsterdam, there appears adefinite gulf, called even on the earlier map "Sirbonis
Lacus".
Schleiden (1858) used the example of the Sirbonic lake to predict that a future
canal through the isthmus would similarly be clogged by sand. In short, conditions in the Sirbonis were not different from the present ones, at least for the last
two millenia: temporary contact with the sea and successive periods of isolation
with occasional storm gales flooding the marshes.
The Sirbonis is the best actualistic example of an old isthmic hypersaline basin
which existed prior to the building ofthe Suez Canal. For this reason, a chapter in
this book is dedicated to the Sirbonis.
Nothing was known in the scientific literature concerning the hydrography
and the biota of the Sirbonis before 1967. In 1967 the lagoon was in contact with
the sea through three openings. The main opening was closed by sediment during
1969-1970 and only in 1971 was the opening again established and deepened, and
former conditions returned. Therefore, on a short time-scale, one could follow to
some extent the presumably normal and cyclic changes in the Sirbonis.
Salinity data are based on Oren (unpublished) Ben-Yami (unpublished), and
Roth (1972,1973). The main sea water influx occurs through Boghaz 1 in the west
and the other openings are chiefly outlets. Lowest salinities are near the openings
and they increase southward to Mitzfaq or towards_ the dead waters in the gulf or
the isolated pools. The annual range of fluctuation is 10-20%0 with a peak in
September-October and a low in March-April (Por, 1971a) (Fig. 12a, b). Absolute
values fluctuate geographically and seasonally between 40-73%0 (Roth, 1973).
When the western opening was closed in the summer of 1970 the salinity in most
35
openings respectively designated as Boghaz 1 and Boghaz 2 are marked on the
map in Figure 12.
It seems that before 1927 the whole basin was a "Sabkha" (meaning in Arabic
a "salt swamp"). During the winter storms, the gales flooded the swamp (as they
do today) and towards the summer the whole area or the majority of it evaporated and turned into a "playa". Before the building of the Suez Canal, which cuts
through Lake Menzaleh between two earthen banks, the waters of this lake
probably communicated at high Nile floods with the Sirbonis. It can be presumed
that the basin became areal lagoon several times during the centuries, carrying
water all the year round. It is of interest to give at some length the references of
Strabo (1st Century of Christian Era) to the Sirbonis. In his words "when the sea
retired, these regions (northern Egypt, author's note) remained bare except that
the Lake Sirbonis remained; then the lake also broke through to the sea and thus
became a bog" (1, 50). In V olume XVI, 760, Strabo gives the dimensions of the
lake: 200 stadia in length and 60 stadia maximum breadth, i.e. some 34 km by 11
km, one-third of the present length and half of the present maximum width. The
lake communicated with the sea through an opening called Ecregma ("the outbreak") somewhat east of Mons Cassius. But in Strabo's time "the Ecregma has
become filled up with earth". At the time of Plinius, about half a century after
Strabo, the "Sirbonis Lacus" was already a medium-sized marsh lake ["nunc est
palus modica" (5, 68)]. Both Strabo and Diodorus of Sicily reported occasional
gales invading the Sirbonis from the sea.
On several old maps such as the 15th Century Weimar map, the 16th Century
map of Tileman Stella and the 18th Century map of Tirion and Loveringh in
Amsterdam, there appears adefinite gulf, called even on the earlier map "Sirbonis
Lacus".
Schleiden (1858) used the example of the Sirbonic lake to predict that a future
canal through the isthmus would similarly be clogged by sand. In short, conditions in the Sirbonis were not different from the present ones, at least for the last
two millenia: temporary contact with the sea and successive periods of isolation
with occasional storm gales flooding the marshes.
The Sirbonis is the best actualistic example of an old isthmic hypersaline basin
which existed prior to the building ofthe Suez Canal. For this reason, a chapter in
this book is dedicated to the Sirbonis.
Nothing was known in the scientific literature concerning the hydrography
and the biota of the Sirbonis before 1967. In 1967 the lagoon was in contact with
the sea through three openings. The main opening was closed by sediment during
1969-1970 and only in 1971 was the opening again established and deepened, and
former conditions returned. Therefore, on a short time-scale, one could follow to
some extent the presumably normal and cyclic changes in the Sirbonis.
Salinity data are based on Oren (unpublished) Ben-Yami (unpublished), and
Roth (1972,1973). The main sea water influx occurs through Boghaz 1 in the west
and the other openings are chiefly outlets. Lowest salinities are near the openings
and they increase southward to Mitzfaq or towards_ the dead waters in the gulf or
the isolated pools. The annual range of fluctuation is 10-20%0 with a peak in
September-October and a low in March-April (Por, 1971a) (Fig. 12a, b). Absolute
values fluctuate geographically and seasonally between 40-73%0 (Roth, 1973).
When the western opening was closed in the summer of 1970 the salinity in most