'Field notes: Mesopotamia. General Staff, India. February, 1917.' [‎36v] (79/350)

64
itself. The channel across the Lake is devious but there are
no difficulties for shallow-draught vessels in the flood-season;
in the low-water season all traffic is stopped except for heliums.
Off Beni Hoteit, and 8 miles east of Hokeika, there are two
more bars, but these and all other obstructions in the Lake
should be removed in three or four months from now by the
powerful dredger already at work, which will dredge a channel
150 feet wide and 6 feet deep below the water. Above Hokeika
the Euphrates presents a broad, deep easily navigable channel
for any river-craft and no difficulties remain but those due
to sand haze and wind which, in the form of the “ Shamal,”
blows particularly strongly on the Hamar Lake.
The prevailing winds in Iraq are from the north and north
west, and the Shamal comes from the latter direction. It
normally begins about the middle of June and blows more
or less continuously for about 40 days, although there are
occasional lulls of from 24 to 48 hours’ duration; its velocity
'occasionally reaches 40 miles per hour and it has the effect
of drying the atmosphere and of affording some relief from
the intolerable summer heat. Other winds in Iraq are the
“• Sharqi,” or east wind, which brings high temperatures with
it, and the south wind which is invariably oppressive and
accompanied by dust.
All the winds may produce shifting lakes and all affect
shipping to_ some extent, whilst the dust they raise increases
the^ difficulties of observation for airmen and adversely affects
their engines by choking them up.
The pulling for artillery teams is very heavy in places, and
even where the surface is good at first it soon cuts up and be
comes heavy, if a succession of vehicles attempt to make a
track. The same applies with even greater force to mechani
cal transport where such can be utilised at all, and anything
heavier than a 30-cwt. lorry will probably break through the
desert crust and get bogged in the mud beneath. Where the 1
ground is soft, solid tyres will cut in from the outset, so pneu
matic tyres are almost an essential. The consumption of
petrol is extraordinarily high (3 to 4 miles per gallon for Peer
less lorries) owing to the impossibility of using the higher gears
even in dry weather, and in wet weather it has been found
that mechanical transport is quite unable to move anywhere.
It will thus be seen that in Iraq, all military problems,