0. 4 A

Session 11. 1921. NEW ZEALAND.

LAND-DRAINAGE METHODS IN AMERICA AND RELATIVE MATTERS (REPORT ON), BY J. B. THOMPSON, CHIEF DRAINAGE ENGINEER, LANDS AND SURVEY DEPARTMENT, NEW ZEALAND.

Laid on the 'ruble of the House of Representatives by l t eave

CONTENTS. I'AOE p AaK Localities visited— Sedimentation Dominion of Canada .. .. .. .. Erosion of Ditches United States of America .. .. .. Erosion of Hill-land and Control of Hill-water The Drainage Movement in Canada and United Flood Protection States — Tide, Sluice, and Lock Gates Canada .. .. .. .. .. Concrete Overfalls, Flumes, and Spillways United States of America .. .. .. Highways Legal Machinery : Drainage Districts— Comparison of the Muck and Peat Soil of the United Petitions .. .. .. .. .. States with that of New Zealand Objections .. .. .. .. .. Comparison of Alluvial Swamp Lands of United Classification .. .. .. .. States and New Zealand Finance .. .. .. .. ■ ■ The Selection of Drainage Machinery and Supplies Comparison .. .. .. .. .. for New Zealand General Practice .. .. .. .. Contracts entered into .. (lasses of Drainage— Requisitions issued Gravity System .. .. .. .. Proposed Distribution of Machinery and Supplies— Salt marsh Drainage .. .. .. .. Consideration Drainage by Pumping .. .. .. Plant-distribution Tile Draining .. .. .. .. Office Excavation of Channels and Ditches — The Future of the Land drainage Movement in New Dipper Dredges .. .. .. .. Zealand— Clam-shell Dredges .. .. .. .. Past History Walking dredges .. .. .. ' .. The Future Drag-line Scraper Excavators .. .. .. Investigations necessary Hydraulic Suction Dredges .. .. .. Recommended Field of Investigation in New Operating-costs of Various Machines .. .. Zealand General .. .. .. .. .. Conclusion— Drainage Excavation Costs, Period 1919-20 .. General Annual Maintenance of Ditches .. .. Personal

I—C. 4a.