under no other restraint than that afforded by small marginal bunds. It is not suggested here that masonry works should therefore be built with the object of gaining control; the matter is merely put forward in this light in order to drive home the fact that to attempt the control of such an enormous quantity as 242,000 cusecs by means of earthen bunds is not of itself a prudent undertaking nor one to be persisted in. At the most, they are in the nature of a temporary but inefficient expedient and are as undesirable as they are necessary.'

Now for the remedy. To understand the prescription the reader should examine the accompanying sketch, in which are represented diagrammatically the conditions above described. For the sake of clearness all minor details have been omitted. It will be seen that, besides many places where the annual breaching of banks by the flood provides a ruinous relief, between Baghdad and Qal'at Salih the Tigris throws off five huge effluents. Of these the uppermost, the Hai, which is well above the region of the marshes, has a large sandbank across its mouth, which prevents it from flowing except at high flood. The other four are perennial, and each one of them takes, or until it was brought under control was accustomed to take, approximately half the water left in the river at the point of effluence. It was in the summer of 1916 that shortage of water in the Narrows compelled the military authorities, who were then solely dependent on the river for their line of communications, to take the first step. In the autumn of that year, amid the lamentations of the local Arabs and the headshakings of many cautious souls, they built a dam across the mouth of the Machariyah channel, with a bye-pass letting enough water down to give drinking water to the local Shaikh and his people and to make navigation by mashhuf (a light skiff used in navigating the marshes) possible. One result, generally expected, the raising of the surface level in the Narrows, did not follow, and therefore it was at first supposed by some that the experiment was a failure. Navigating officers, however, began to find that they could get through with more deeply laden barges, and soundings taken in cross-sections of the river bed confirmed their story. The surface level did not rise, because the river was scouring out its

channel. In point of fact the surface level has since been gradually falling; and, if the policy advocated by Major Walton be steadily adhered to, those who live may yet see the high banks spoken of by Chesney standing where they ought and confining the waters of the river to their proper bed.

In 1917, beyond systematic repair and restoration of the existing flood banks, nothing was done. The omission was deliberate. For if this policy, which aims at the restoration of what are believed to be natural conditions, is to succeed, it must work as nature works, gradually. The river must be given time to accommodate itself to one change, before another is attempted. It may not be out of place here to mention that the lugubrious predictions of the Arabs have been wholly falsified. It is true that in many areas where, before the Machariyah was dammed, rice was grown, that crop can no longer be cultivated. But, with the contraction of the marsh, new lands of at least equal value have emerged, and the Chahalah, the next effluent above the Machariyah, in spite of what was done to it in subsequent years, has proved fully equal to providing them with ample water. In addition, the area of lands suitable for wheat and barley has considerably expanded. So, on the whole, the balance, even of immediate advantage, is in favour of the experiment; and the local cultivators have been rewarded for their loyal acceptance of a measure which was wholly unpalatable to them. One drawback they do feel the restriction of navigation for boats of draught in the old waterways. But this can be arranged by the provision of more generous bye-passes, or rather by the construction of locks beside the regulators. For it will be many years before the closure of the barriers during the rising flood will be feasible; and till this can be done, although the marsh area will contract, there will still be enormous quantities of spill, and the face of the country will not be radically altered.

In 1918 again, great attention was paid to the flood banks, and temporary wooden barriers were erected across the mouths of the Majar Kabir and Chahalah effluents. These were not put into operation until late in September, and so did not affect the rice crop, which

does not require watering after that date. These barriers were very successful in improving navigation through the Narrows in the low-water season. In 1919, a permanent solid masonry regulator was built on the Majar Kabir, and a permanent timber-pile structure on the Chahalah. In 1920, the construction of a timber-pile regulator, similar to that on the Chahalah, had been planned for the mouth of the Butairah effluent. This huge waterway takes out on the right bank about 15 miles above 'Amarah and runs through little-known regions to the Hammar Lake, which, indeed, as we have seen, is largely fed by it. Of late years the Butairah has been gaining at the expense of the river, whose place it might at any time usurp. Owing, however, to the disturbed state of the country, the plan was deferred. Its necessity has, however, been recognised by the provisional administration, which in July last voted the sum required for its construction-two and a half lakhs of rupees. The cost of these works, except the original dam on the Machariyah, which was built entirely by military labour, has been defrayed out of Mesopotamian revenues, and they have not cost the British taxpayer anything. The results already secured are remarkable. Writing in 1919, the Director of Irrigation was able to say that the carrying capacity of the Narrows had already been increased by 200 per cent. and the river had sunk into its bed with a resultant lowering of surface-water levels.

Thus, on the Tigris at least, the heaviest part of the work is done, but no time should be lost in dealing with the Butairah. The problems offered by the Euphrates are certainly not less difficult; but the chances of success can be better gauged after the engineers have seen the effect of bringing under control the Butairah, which carries so much Tigris water into the Euphrates area. Unrelaxing vigilance on both rivers, together with sustained effort in the maintenance of flood-protection banks, will still be necessary until the lowering of surface levels shall render banks on their present scale superfluous. Besides this, the Government of the country must, in practice, as well as in theory, reserve to itself the sole control of the rivers. The promiscuous digging of effluents must not be allowed to begin again; and pari passu, as each existing effluent is brought under

control or stopped, arrangements must be made for the irrigation, under control, of the areas now dependent on it. Riparian cultivation cannot, of course, be checked. On the contrary, it should be encouraged; but encroachment below high-flood level must be sternly banned, and those who dig cross-channels in the river bed below that level must be compelled to scatter the spoil which they throw up in so doing. All this can be done without serious inconvenience to those concerned; but whether the autonomous administrators will have the foresight to take these measures and the power to enforce them, can scarcely be predicted at present.

These desiderata are pleasing to the soul of the irrigation engineer, but are not an end in themselves. For what tangible reward can the people of Mesopotamia look, if the precepts are duly observed? In the first place, until the rivers are brought to a stable regimen, no comprehensive scheme of irrigation can be worked out and no attempt made to conserve for the use of man the superfluity of water which the annual floods bring. On the policy of river control, therefore, hangs the future of irrigation; and so also, over a large area, does the improvement of agricultural methods. To this policy the Arab may look for relief from his present burden of work upon the flood banks, as well as for the maintenance of a navigable waterway in the Tigris, and perhaps for the restoration of one in the Euphrates. At the same time, this policy will give back to the plough millions of acres which are now covered by unprofitable marsh; and some future Amir at no very distant date may be able to rehearse, with truth, the boast of Lugal-Zaggisi, King of Erech, who records in an inscription, dated circa 2800 B.C., how he caused the lands to dwell in security, he watered the land with waters of joy.'

EVELYN HOWELL.