D —4
B. OPERATION AND MAINTENANCE 1. Power-stations Coleridge. —Owing to favourable rainfalls the lake-level fell to 1,663-96 ft. only by the 24th September, this being a decided improvement on the previous year. Overflow level, 1,673-5 ft., reached by 12th December, was maintained until after 31st March, 1949. A new record maximum half-hourly demand of 42,440 kW. was recorded at 1200 hours on 7th March, 1949. This peak was an overload of 23 per cent, on the station rated capacity of 34,500 kW. Heavy expenditure was incurred on maintenance at the Harper intake, the work including fairly extensive repairs to the main diversion groyne and renewal of apron nets along east side of the long groyne. Willows were planted along the banks of the lake outlet channel. The new bridge built by the Ministry of Works over the Kyton River was opened for traffic in June.
Machine-running Times
Waitaki. —The average river flow during the year was 12,800 cusecs, compared with. 9,625 cusecs during the previous year. The highest river flow since the station commenced operating was recorded on 3rd November, 1948, when, with 6 ft. of water going over the crest of the dam, the computed total river flow at the peak of the flood was 75,500 cusecs. A second high flood occurred in February, when a peak flow of 43,000 cusecs was recorded on the 24th. The lowest weekly average flow was 4,479 cusecs during the week ended 19th September.
Machine-running Times
19
Time on Load. Time Idle. Time Under Repair. Percentage Generator No. rfemand j Remand (Hours). ( Hours >- Availability Hours. Percentage. Hours. Percentage. for Service. 1 5,723 65-3 2,996 34-2 41 99-5 2 5,285 60-3 2,604 29-7 . 871 90-0 3 4,995 57-0 2,756 31-5 1,009 j 88-5 4 1,895 21-6 6,647 75-9 218 97-5 5 1,743 19-9 5,878 67-1 1,139 1 87-0 6 1,468 16-8 5,348 61-0 1,944 1 77-8 7 1,786 20-4 6,650 75-9 324 96-3 8 3,242 37-0 5,491 62-7 27 99-7 9 3,465 39-6 5,163 58-9 132 98-5
Time on Load. Time Idle. Time under Repair. Percentage Generator No. Not in Demand (Hours). Availability Hours. Percentage. Hours. Percentage. In Demand (Hours). for Service. 1 7,570 86-4 1,172 13-4 18 99-8 2 7,362 84-0 1.395 15-9 3 99-9 3 5,749 65-6 3,008 34-3 3 99-9 4 5,520 63-0 3,210 36-6 30 99-6 5* 227 89-7 26 10-3 100-0 *N< ). 5 unit became available for routine full-load running on 21st March, 1949.