It is probable that this failure of the water supply had had much to do with the disappearance of Osman Digna's forces.
Graham's force had brought with it only three days' supply of water, and this failure of the wells at Tamaai rendered it dangerous to advance against Tamanieb, for should the wells there be found to be also waterless, the position of the army would become very serious.
Under these circumstances, and in view of the retirement of the enemy, and their evident inability or indisposition to meet the force, the General considered it best to withdraw, as it would have been fruitless to attempt to follow Osman Digna into the mountainous country with no water for the transport animals.
At 10.20 a.m. Graham ordered the withdrawal of the force, by alternate brigades, from the position which had been taken up. By 10.40 a.m. the troops had recrossed the khor, the movement being covered by two Horse Artillery guns on the ridge to the north, which fired a few rounds of shrapnel at detached parties of the enemy.
New Tamaai was ordered to be destroyed, and it was fired as the troops retired through it. Considerable quantities of ammunition were destroyed. Osman Digna's residence is believed to have been among the huts burnt.
At noon the force reached No. 2 zeriba at the Teselah Hill. As the troops fell back a handful of Arabs made their way, parallel to the line of march, along the distant hills to the right, keeping up a running fire on the British column. From zeriba No. 2 the force moved gradually back to the other zeriba, and thence to Souakim.
The total casualties were one man killed and six wounded. Only seven men fell out during the march.
It was a severe disappointment to the troops that, after all their exertions, the marches in the blazing sun to and from the zeribas, and the loss of life in previous engagements, the enemy should refuse to await the attack, and that the want of water should prevent the column following him up. The temporary occupation, followed by the destruction, of a wretched village, was a very inadequate result to show after such extensive preparation, and so much labour and effort.
From the 11th to the 20th April, Graham was occupied in making reconnaissances to Hasheen, Otao, Deberet, and Tambouk, taking a few prisoners, and capturing sheep and cattle.
The construction of the railway was at the same time pushed forward, till it was close to Otao, making altogether a total distance of eighteen miles.