SOLOMON’S KNOB DAM

New Zealand Times, Volume XXXII, Issue 7048, 9 February 1910, Page 5

SOLOMON’S KNOB DAM

CITY COUNCILLORS’ VISIT OF INSPECTION. THE PRESENT STATE OF WORK. -MAIN DUPLICATION ADVOCATED. The city .fathers paid their annual visit of inspection to the Wainul-o-mata, waterworks yesterday. Although rain threatened in tho morning it was doomed expedient to proceed and a party consisting of about seventy ladies and gentlemen left tho Town Hall at a little after D o’clock in cabs and brakes. In addition to councillors and their wives most of tho heads of tho various corporation departments made tho trip. / On tho way oat a deviation was made at Petone, the opportunity .being takon to inspect the new pipe and traffic bridge over tho Hutt river which is now in course of construction. AYaimii was reached at about half past 12 ; and the rain which had kept off until then or no down in torrents. Happily dinner was ready and the largo marquee, where a firstclass luncheon was provided, proved a welcome haven. LARGE CTTY WORKS.

After lunch had been partaken of, tho Hon. T. W. Hislop, who had been specially invited, proposed the health of tho Mayor (Dr A. K. Newman). Ho said ho‘appreciated tho manner in which the large works of tho city were being carried out. It was most satisfactory to those who- had taken an active interest in such matters. Ho thanked tho Mayor for the hearty welcome extended and reminded tho company that there were always persons ready to take tho place of those who retired' from civic life.

In response, Dr Newman harked back to over twenty years ago when tho council was in a “mess” over its waterworks, but that had all been remedied now and the public had nothing to fear while Mr IV. H. Morton was in charge of the engineer’s department. One of tho most important works which tho council would soon have to face was the construction of another main to Wellington. The work would cost about £150,000. He hoped councillors would resist all demands for other loans and concentrate their energies on the work he had just mentioned.

Mr J. Smith, the senior councillor present, proposed the toast of the contractors —Messrs Martin, Hurrell and Snaddon.

In tho course of a short reply Mr Q. Snaddon mentioned that the Solomon’s Knob dam would be completed in six or nine months’ time. THE NEiW DAM.

Although rain was still falling heavily .at half-past 3, most of the councillors, accompanied by the city engineer and several other officers of the council, proceeded to the site of the construction works at Solomon’s Knob, Mr Morton explaining the position. The dam is not of the old-time solid variety, but Is being constructed on American lines of reinforced concrete, which exports , state 'presents far less risk of accident than Is tho case with, the solid wall dam. The rew stylo of construction consists of tho face wall ijhree feet in thickness, lessening to two feet, and sloping -upstream at an angle of 45 degrees, having for its support a series ■ of vertical reinforced concrete walls twelve feet apart for the entire length! of the dam. The walls are being erected at right angles to the face and extend ■ed down-stream for a distance that, when the, pressure of water bb calculated mathematically, - the centre pressure is in the middle third of the wall. ' 'ln Bomo instances the downstream side of the dam is simply a row of wall ends /or buttresses, either sloping sligjbtly or vertical. In the ease of Solomon’s .Knob that side of the dam is walled half-way 'up and the earth that .has been removed' in sinking the foundations, oto., has been thrown against this wall to act as an extra stiffener. When completed the, dam will have a length of 540 ft, 107 ft of which will he a by-wash situated onodihird the way a'croSs (in which section the back of the dam will be walled to the top). This is a further innovation in dam construction. The height of the sloping face will Ibe 64ft and the perpendicular height from tho ground to the orevvt of the dam 47ft, and to the torest of the by-wash 43ft. The supporting walls are being constructed two feet thick, so that though they occur at intervals of 12ft tho structure compared with the old style dam is hollow. . THE PRESENT POSITION. The Work has now reached a . Very interesting stage. The Whole of the out off -wall now - extendh between the two banks on either side of the valley ; and the permanent reinforced concrete floor of the dam is completed. The vertical diaphium walls which will support the deck or apron of the reservoir are now being .brought vertically upwards. The apron of the wall whnlch supports the water in the reservoir is also advanced with its vertical supports. AH tho henlvy work has been .completed and tho remainder will be (Straight slatting. Scour pipes are all built ;in position and no serious danger is now to-be .feared by breaks owing (to flood water. One of the (conditions of the contract is that all bush and scrub—whether alive' or dead—in the urea to be submerged shall be felled. !Ab the area is over twenty-six acres in extant And tho land bos had to bo cleared for eighteen- feet horizontally above'high Water (mark the task has been exceedingly heavy. Provision has also been made for the raising of (the dam several feet should the necessity arise fin the future. THE CAPACITY. The maximum depth of water when the now dam is filled will be 50£t. The Capacity of tho reservoir will be about 140 -millicm gallons. It has been computed that when the reservoir is (full there will be a pressure pf 1035 tons on tho icentro of oaoh vertical wall (and two (tons pressure on every foot of fthe foundlaiticta.

Riafin .ceased at 4 o’clock, .and a start was then made for home, the city being (reached at about half-past six.