HAWERA WATER SUPPLY

Taranaki Daily News, 4 December 1930, Page 12

HAWERA WATER SUPPLY

BOOSTER PLANT “COMPLETED RAISING PRESSURE IN THE TOWN. • ■! COST OF-DUPLICATION SA VED. Although the Hawera water tower safeguards the town from the aspect of fire fighting, the pressure in the borough for domestic consumption has been poor for some time. Duplication of the ten-inch main was first considered but the cost was so great as to bo almost out of the question. The problem was how to supply ratepayers at a- reasonable cost and the solution of providing a boosting plant was suggested by the engineer, Mr. J. Sturrock. The provision of the booster was discussed in November, 1929, and early this year it was decided to proceed with the proposal. The latest plant was imported from England and erected on the corner of Waihi and. Glover Roads. The installation has been completed as the booster will be in operation during the dry months of the summer and autumn.

Hawera’s water supply is derived from the Kapuni River at a point near the lower end of Palmer Road. From the: intake the water is taken to ;a settling tank, flowing thence by gravitation to the town. The borough has no reservoir other than , the water to wer, , which is used solely for fire prevention purposes. . In recent years the pressure has been gradually reduced during the periods when the draw-off is at its maximum. It has frequently fallen to 81b per square inch, which is close to the danger limit. The booster will raise the pressure in the middle of tiie town to about 401 b even when the draw-off is heavy.

During the night the main has been but little drawn upon and there has been, in consequence, a large surplus of water at this time. The purpose of the boosting plant is, briefly ..to store up the night surplus and pump it into tho borough reticulation during the day, when the main is unequal to the task. A large concrete storage tank, holding 50,000 gallons, has been built. This holds the night surplus and water enter?. it through a spring-loaded valve by means of which the quantity can be regulated. The boosters themselves consist of two electrically driven 40 horse-power- centrifugal pumps, one of which operates ■while the other acts as a stand-by. The power is obtained from the South Taranaki Power Board, whose engineers have attended to the electrical part of the installation.

An ingenious electrical system controls the pumps so that they automat-, ically shut themselves off when the normal pressure in the mains is sufficient and resume work when the town is being insufficiently supplied. Should a main burst anothei’ control, operated by a sudden fall in pressure, stops the engine and shows the pressure on a dial. The engine is also cut off when the storage tank empties or any fault occurs in the electric system. In connection with this electrical control gear there is a large steel cylinder, which is filled with compressed air and obviates shock to the plant permitting brief spells of rest between operations. A /

When the plant is operating the pressure is ■ raised to about 501 b at the 'booster site and close on 401 b in town. This represents an enormous improvement upon the old minimum of 81b and it is expected that the booster will help to postpone the cost of duplication for many years to come. The duplication of the main was estimated to cost at least £30,000 and, if the job was done in the best way possible, well over £40,000. The expenditure on installing the booster will be about £3OOO, No information as to running costs is yet available and no figures can be obtained until the plant has been. in operation for some time. The probability is that for every £lOOO that would have been spent on interest and sinking fund for a duplication loan, the booster - will cost £lOO.

It was recently reported to the borough council that every additional service to residents-of’the town outside the borough must affect the pressure, but to only what might be called, a microscopic degree, and the effect of 26 additional services would not be perceptible on a pressure gauge. The council was advised to decide that no further inight supplies beyond 20 should be granted until the full extent of the benefits of the booster were ascertained. Several night services have since been granted.