DRAINAGE OPERATIONS.

Hauraki Plains Gazette, Volume XXXIV, Issue 4537, 9 March 1923, Page 8

DRAINAGE OPERATIONS.

SUCCESSFUL UNDERTAKING. The Piako Swamp, as the Plains were originally called, was at one time thought to be useless for agricultural purposes owing to its swampy nature and its frequent flooding. However, a scheme of drainage was devised, and for that purpose the “Hauraki Plains Act” was z passed by Parliament in 190’8. Work was commenced immediately,

and has proceeded' without interruption ever since. It is proposed to drain an area pf 90,000 acres, and up (to the present just over 45,000 acres have been completed and opened up for settlement. The job has been a unique one, owing to the curious formation of the land, and many stiff engineering problems have had to be solved. Practically all of the land is below high spring tide level, and the fall is away from the sea. All that is, draining the land is the fall of the tide. The river has had to be stopbanked and 'flood-gates have had to be erected to prevent the tide coming in.

One of the next big jobs to be done is that of improving the bed of the river so as to lower the low tide level in the upper reaches. To this end three dredges are to work in the river from Ngatea southwards. The river has already been very greatly improved. It has been widened and deepened, and horseshoe bends have been removed.

The Waitakaruru-Maukoro canal, which, when completed, will drain an enormous area of land, is a job presenting some peculiar engineering difficulties. Six miles from the sea the country is 30ft. above mean sea level, and consists of 25ft of peat on liquid clay. The method of dredging adopted has been to dig as deep as the nature of t,he country would allow and pass on, to return when the peahad consolidated sufficiently. To construct a dam in the peat to hold the water in which the dredge floats has been another problem. When the canal is completed it will be 15 miles long, and the peat will have consolidated to four or five feet. The Awaiti canal, which is to be 10 miles long, will not present much difficulty, but the work is at present hung up pending an adjustment with the Elstow Drainage Board. Two-and a half miles have been done, and when work is recommenced it will be by a new type of steam-driven dipper- dredge. All this work, including roading, stop-bank f construction, bridge and wharf building, etc., is being proceeded with at the sa,me time, and an enormous plant is necessary.

The Department has seven dredges, including four land dredges, in operas tion at present, and three more are in different stages of construction. They have an extensive road-making plant, including motor trucks, tractors, tramline and rail tractors, scoops, graders, etc., besides steanaers, launches, punts, private wharves, metal' tips, etc. At Kcrepeehi there are extensive fitting shops, with machinery driven by electricity, and a slip on which a poujtoon 80ft by 20ft by 6ft is in course of construction. One feature of the work is that in many cases it is only possible to carry on during the summer months.

When the work will be completed it is impossible to say, but it is safe to assume that there will always -be something to do, as drains will have to be kept cleaned out. An amendment to the Hauraki Plains Act provides that all land that has been occupied for five years prior to March 31, 1923, becomes liable for county rates. On that date the Government is handing over to the Hauraki Plains County Council 38% miles of metalled roads and 27% miles of formed roads, and to the Piako County Council 27% miles of formed ijoads.