LAND DRAINAGE.

Hauraki Plains Gazette, Volume XXXIII, Issue 4421, 31 May 1922, Page 3

LAND DRAINAGE.

NEW ZEALAND AND AMERICA!.

MR. .J, B. THOMPSON’S REPORT. ' No. 1. .

[Tie following is a reprint of the report of Mr. J. B. Thompson, Chief Drainage Engineer to the New Zealand Government, on his observations in the United States and Canada, anl comparisons with New. Zealand works. The information contained therein is very interesting, and should be filed for, future reference by all those interested in land drainage and reclamation works generally. The report will be published in sections. as space permits, until completed.—Ed.., "Gazette.”] Sir, —In accordance with your instructions to inquire into the latest methods of land drainage m practice in the above countries, and to select suitable up-to date plant for prosecuting work in this Dominion, I departed from Auckland on May 6y 1920, and returned on March', 1921, I have advised you from time to time of the several places '■ visited and my impressions of the works seen in progress, and now propose to as briefly as possible condense this matter, and also deal; with items coming under special headings. . ■ LOCALITIES Dominion of Canada.—l successively visited the Provinces of British Columbia, Alberta, Manitoba, and Ottawa, and got in touch with the various authorities controlling drainage. I found that these provinces were on the eve of embarking on very extensive operations, but that the greater portion of the land to be drained came within the category of periodically flooded lands. There did not appear to be any extensive aiea., Of the class of country I desired to see, such as muck and peat lands ; and, after discussing, the subject very fully with Mr. Dawson, Chief Irrigation Engineer, Calgary ; Mr. Bowman, Provincial Drainage Engineer; the Manitoba Drainage Commissioners. Winnipeg; and Mr. E. S. Drake, Director of Reclamation Service, Ottawa I decided that my best field of observation would be in the United States of America, seeing' that our conditions were more similar,

1,-however, took the opportunity of inspecting levee' works along the Fraser River, British Columbia; drainage of; irrigated lands in Alberta ; drainage of gumbo lands in Manitoba ; and operations being conducted on peaty country in Ontario. AU this work was being operated by dipper dredges,, w,alkingj-dippcrs, and drag-line excavators. Very.excellent work was being done, 'blit none of it under as wet conditions as usually prevail in New Zealand. Maintenance, I found,, was more or less a dead-.'etter, and this, the authorities informed me, was still an unsolved problem. With the exception of the machine ! maintenance of irrigation ditches near Calgary I saw no mechanical means for cleaning. For the construction of all classes of large ditches hand labour has been superseded by machinery of various classes, and of these walking-dippers and drag-lines ,are, much in favour, and doing excellent work. Special facilities were afforded me of seeing the work of several dipper and clam-shell dredges operating at Toronto and Montreal, but these machines were generally tori' large for our operations in this Dominion. In connection with river protection works, it was noted that rockfilled cribbing was in general use and proving very satisfactory. This form of protectibn owes much ofl its popularity to the nearness of lumber supplies.

United States of America.—l proceeded from -Montreal, Canada, to Washington, D.C., and- presented my credentials to His Excellency -.he British Ambassador and the Secretary of State, and was at once placed in touch with the officers of the Drainage Investigations branch, o" the Department of Agriculture. These gentlemen immediately prepared an itinerary, covering all the main drainage projects in several States, and either accompanied me thereto or else made arrangements for me to meet engineers at the several points Drainage, operations were .inspected in the following States: Minnesota, Wisconsin, Michigan, Illinois, lowa, Ohia, North Carolina, Missouri, Arkansas, Louisiana!, Indiana, Kentucky, Tennessee, Florida, and California The methods used for reclamation were closely observed, and much learned from the various eminent engineers .and authorities , met with. Very great importance is attached to the necessity for bringing to profit -ill flooded and- swamp lands, as it is recognised (as in New Zealand) that probably the . richest land is the swamp area. My observations as regards respective qualities convince! jne that there is rio better swamp area in America than can be found in New Zealand ; but the area in the former country is quite staggering. This, of course, is very obvious. In the United States the wet areas are ap proximately as fjollows : Swamp, 66, ■ 000,000 acres ; periodically overflowed, 31,000,000 acres; tidal marsh, 4,000.000 acres. Probably three-fourths Oif these lands are timbered, and in many instances cut over.