Plate XXVI.
Stanford Geog. Estab. London
SKETCH MAP OF THE GROUND BETWEEN HAWÂRAT-EL-MAQTA AND HAWÂRAH PYRAMID.
Note.—The ravines are not correctly mapped, but only sketched in to show generally how the ground is broken up.
I give this description to indicate what interesting problems there are to solve, or lose oneself in conjectures about, in various parts of the Fayûm Province, and especially in the neighbourhood of Hawârat-el-Maqta and the wonderful Labyrinth.
Given then the actual conditions of a considerable difference of level, continually increasing, between the water at its entrance to the Fayûm, and the lake surface, and, from an irrigation point of view, a steep surface slope to the country under irrigation, ravines would commence to form along the lines where drainage and the water, discharged by canal breaches, would collect to flow towards the lake. Wherever also an inundated area, surrounded by banks, effected the discharge of the water contained in the basin, there would be made the beginning of a ravine, which may afterwards have been utilised as an irrigation or drainage channel.
The main drainage lines of the north and south were naturally formed along the lines, where the rounded concentric contours of the central part of the Fayûm double back to run along the north and south sides of the depression, as shown in the diagram ([Plate XIX.]). At many points the rock being reached, further deepening of the channel was checked. The rock being close to the surface along the upper part of the course of the south main drainage line, a deep ravine has not been formed, until after the village of Miniet-el-Hêt is passed.
But the north drainage line has been scoured out and cut back to the banks of the Bahr Yûsuf itself, so that deep ravines exist within a short distance of and parallel to its present watercourse. Into these ravines a breach would precipitate all the main canal supply, if such were to occur from negligence or from rashly permitting irrigation to be conducted from heads roughly constructed by the fellahîn in the Bahr Yûsuf banks.
Probably some small village channel, allowed to take off directly from the Bahr Yûsuf without a proper head, and used to irrigate some low lands along the slopes of the main ravine, caused a minor ravine to commence and grow, until, cutting back as far as its head, it eventually gave rise to the breach of 1820, which resulted in a widening out of the branch ravine until it attained its present dimensions.