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(b) Technical Committee, Hydrological Data. —While there was no need for a meeting of this Committee during the year, members have been kept informed of progress to date by correspondence between themselves. . (c). Information and Educational Advisory Committee. —This Committee is comprised of representatives of the Council, its staff, and the Catchment Boards Association, and has done valuable work in preparing plans for the Information Service to suit the Council's and Catchment Board's needs. ' (d) Advisory and Co-ordinating Committee on the Aerial Distribution of Fertilizer and Seeds. —This Committee has been very active, and the team-work of those concerned—Federated Farmers, fertilizer-manufacturers, and Departments of State (Lands, Forestry, Works, Agriculture, Air, and Scientific and Industrial Research) —has made the considerable progress possible. HYDROLOGY Further progress has been made by Meteorological Services of Air Department in intensifying, in accordance with Council's request in May, 1946, the national skeleton network of rainfall stations. At the beginning of the year there were, in the national network some 830 manual and 45 automatic rain-gauges, whereas by March, 1950, thesenumbers had been increased to 870 manual and 61 automatic rain-gauges. Again, most of these increases have been made in sparsely populated areas, the increase being made possible by landholders agreeing to care for the instruments and volunteering to take observations. There are still, however, vast unpopulated areas in the headwaters of nearly every river catchment where the Council desires further rain-gauges to be installed, but until a reasonably cheap and reliable recording rain and snow gauge is available it will not be possible to obtain an adequate and complete first cover for themore important river catchments. Some progress has been made by the Director of Meteorological Services in the further complete analysis of past rainfall records, as required by engineers who are concerned with the safe hydraulic design of new hydraulic structures, but inadequate staffs and the necessity to concentrate on day-to-day forecasting means that only a very limited amount of data can be provided at present. The tabulation of all excessive past rainfalls at manual rain-gauge stations is completed, while analysis of past automatic rain-gauge records to determine excessive falls in intervals of time from five minutes, upwards is almost complete. The heaviest rainfall recorded during the year was at New Plymouth on Bth January, when 0-38 in. fell in five minutes, 0-51 in. in ten minutes,, and 1-01 in. in twenty minutes. During the year Meteorological Office Note No. 33, " The Frequency of Heavy Rainfalls in New Zealand," by Dr. C. J. Seelye, has become available for general distribution. To assist in the establishment of values for mean sea-level in the Bay of Plenty, an automatic tide-gauge installation was completed at Mount Maunganui, and a recorder is under construction at Ohope, Whakatane. The Waimana, Rangitaiki, and Tarawera Rivers automatic recording-stations are in hand. In the Gisborne district the improvement of the reaches for automatic gauging-stations on the Waikohu, Wharekopae, and Waipaoa Rivers have been completed. A water-level recorder was installed at Foxton to establish tidal effects. Proposals are complete for a recording-station at Maoribank on Hutt River, while construction is in hand for automatic stations on Horokiwi Stream at Porirua, Upper Wairau River (Marlborough), Buller River at Lake Rotoiti, and twomore recorders on Lake Bllesmere. A recording anemometer has been installed at Lake Ellesmere in order to relate wind velocities to water-levels. The Ahuriri River gaugingstation is completed, while that on Lake Hauroko is in hand. Some 29 staff gauges have been placed in the Invercargill district for flood-warning purposes.

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