THE CITY’S WATER

Wanganui Chronicle, Volume LXXXIII, Issue 19919, 15 August 1927, Page 6

THE CITY’S WATER

IMPRISONED AT OKEHU NEW DAM COMPLETED Set in the picturesque surroundings of the Okehu Valley, a newly completed dam imprisons 15,000,000 gallons of water for the city’s needs. This new dam has been constructed according to the design of . the city engineer (Mr N. Crofton Staveley) and the work is a very creditable achievement. The old djam had a capacity of 5,000,000 gallons, and the new structure which is 50 feet in height and 26 feet through at the Case, has been built over it. Approximately 6000 tons of concrete (2200 cubic yards) were used in the construction of the wall. The catchment area is 2000 acres in extent and includes the Okehu and Mangahoropito valleys. No stock is permitted to graze on this water shed reserve. In 1918 a tunnel 25 chains in length was driven through to the Mangahoropito stream, and when necessary a daily flow of 500,000 gallons can be tiiverted through this tunnel to the dam. The Okehu stream has a daily flow of 1,000,000 gallons.

From the dam the water is taken down the Okehu Valley in a 16-inc'h main and through a tunnelled section to a break-pressure tank near Mr G. F. Moore’s Bushy Park estate. Thence a 12-inch main takes the flow to the reservoir at Westmere.

This stretch of pipe-line, 11 miles in length, has been duplicated by a 14inch main laid by the Wanganui Spiral Pipe Company, and the City Council expects to take it over from the contractors shortly. Some trouble has been experienced from washouts caused by heavy falls of snow and portions of the pipe-line 'nave had to bo built on concrete piers down the valley. The Westmere reservoir holds 5,000,000 gallons and the flow is carried to Wanganui by a 15-inch main. The principal point about Wanganui’s water-supply system is that it is a gravitational one, and no pumping is required. Water will have to be pumped up tho Bastia Tower, but this is principally to provide pressure for firefighting purposes on the higher levels of the city. The Okehu a-am is 1000 feet above sea level, the break-pressure tank at Bushy Park is at an altitude of 802 feet, and the reservoir fs 401 feet above sea level. By this means t'he pressure is brought down to one suitable for domestic purposesThe headworks are well cared for by the caretaker (Mr C. K. Knudson) and when the weather clears and scrubcutting and painting are completed the dam will bo filled to its capacity.