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APPENDIX III.—LAND DRAINAGE OPERATIONS. (R. G. MacMorban, Chief Drainage Engineer.) As usual, the main operations of this Branch have been connected with the major land-drainage works, and, as laid down by statute, separate reports have been prepared covering Hauraki Plains, Rangitaiki, Kaitaia, Hikurangi, Waihi, and Poukawa drainage-works. Inspections and reports on general drainage matters have been made in several cases, the principal being at Wellsford, Taupo, Tatarariki, Tikinui, Shines Outlet, Kuku, Tauhei, Muir's Swamp, Jed River, Aotea Harbour Reclamation, and Oreti Peat Bog. Works carried out by local authorities under Government grants and subsidies have been supervised and inspected, with a total amount of £16,660 passed for payment in this connection. Hereunder is a short summary of general work carried out by this Branch : — Flax-planting, Hauraki Plains. —As a means of providing relief works for unemployed, a low-lying alluvial area of 568 acres on the Hauraki Plains, near Kaihere, was planted in flax in the previous year. This work was continued during the past planting-season on adjoining area. Approximately one-third of the area selected was alluvial, the balance being peat with a surface-elevation ranging from high spring-tide level to about 12 ft. above that mark, whilst the elevation of the clay subsoil varied from spring-tide level to some 8 ft. below that level. About twenty men were engaged from June until September in clearing, draining, gathering, and planting flax-plants. In all, 319 acres were dealt with, entailing the collecting and planting of some 242,800 flax-plants. Later in the year the work of cutting and poisoning blackberry in the area under flax was undertaken. It is too early to give any definite result of poisoning with arsenic spray. The total area of flax-plantations is now 887 acres, of which 700 acres is alluvial swamp and the balance is peat. On the alluvial land the planted flax is flourishing, but on the peat area the results are not so satisfactory. It is anticipated that the flax on the former area should be ready for milling in the summer of 1931-32. Motutangi Block. —During the year 1 mile 7 chains of outlet drain was constructed, but the main outfall constructed in April, 1928, is at present in bad order owing to silt-deposits and growth of weeds. This drain is of flat grade and of little practical use unless cleared at least once every year. The settlers concerned have formed a drainage district under the jurisdiction of the Mangonui County Council so this matter of maintenance is one for the settlers themselves. Taupiri Drainage and River District. —A report on the southern portion of this area was prepared in 1925 under the heading of " Woodlands Swamp " and dealt with the area in the Mangawara River basin approximately within, the triangle bounded by Hamilton, Morrinsville, and Taupiri, an area of approximately 57,000 acres of flat land. During the last year the field data was extended over the balance of the flat lands of approximately 20,000 acres in the Mangawara basin. This work entailed the following : — Miles eh. Miles eh. Traverse .. .. 69 12 Cross-sections (drain) .. .. 2 14 Levels .. .. .. .. 95 58 Watershed definition .. .. 40 0 Check levels .. .. .. 27 67 Swamp-edge .. .. .. 30 0 Scrub-cutting . . .. 3 13 Current-meter gaugings .. 29 0 Peat-soundings .. . . .. 3 11 Staff gauges installed .. .. 6 0 Cross-sections (river) .. .. 3 56 Upon the completion of the field-work, plans and a report were prepared and copies of these have been forwarded to the amalgamation committee, which is working with the object of amalgamating all the Boards —both Drainage and River —in the Mangawara watershed. During last session of Parliament, statutory authority was provided by the passing of the Taupiri Drainage and River District Act for the control under one Board of the area on the Mangawara Basin. Proposed external boundaries of the new district, as well as ward boundaries, have been demarcated and forwarded to the committee. In order to further enhance the data obtained, arrangements have been made for the staff gauges erected in the Mangawara to be read by settlers in the vicinity, and results forwarded here for use by the new Board at a later date. Ngatea-Kaihere Road, Hauraki Plains. —The work of metalling the gap in the road along the Puhanga Canal and Piako River from Puhanga Canal to the Kaihere Landing was completed. Two-thirds of the cost was found by the Public Works Fund, the Hauraki Plains County Council finding the remaining one-third. A through metal surface was provided prior to last winter, but the metalling was not actually completed until October, 1929. During the year 32 chains of road was re-formed, and 3,519 cubic yards of metal laid, covering 1 mile 33 chains. Kerepeehi Block Roads Metalling, Hauraki Plains. —In view of the opening for selection in May, 1930, of the Crown sections in the Kerepeehi Block it was desirable to proceed with the metalling of the access roads for which a pound-for-pound subsidy was provided from the Public Works Fund. The work was commenced in October, and by the end of the period under review 2 miles 14 chains of Awaiti Canal Western Embankment Road had been re-formed, also 1 mile