DRAINING THE PLAINS.

Hauraki Plains Gazette, Volume XXXVII, Issue 5008, 2 August 1926, Page 2

DRAINING THE PLAINS.

A SOLUTION FOUND.

ELECTRICALLY DRIVEN PUMPS.

CHEAP AND EFFECTIVE METHOD.

EVer since the complexity of the problem of draining the laaid p£ the Hauraki Plains has became fully realised two facetious suggestions, have frequently been made. One was to employ pumps; and the dther to employ boilers to convert the water into steam and blow it away. Until iecently one suggestion was taken as seriously as the other, bub with the coming df. electric pohver and the realisation that in some areas .where there is little or no tidal action, when it is, most required, the existing methods of dealing with the - water would never be entirely successful and the land inundated would have to remain in that state for several days or perhaps weeks until the water from the higher country had passed down the river, the question of pumping was given serious consideration. On investigation it was found to be a feasible proposition, and on tria.l a sound, economic, effective, and simple solution.

The credit for the scheme must be given to Mr L. C. Marchant, Whose, land on the island block between the Puhanga canal and Piako River was subject to s,erious flooding after heavy rain by water ifrom the other parts of the, block. His section being the lowest on the island, and there being little tidal action in the river when it is swollen with up-country water, the land becoines inundated for long periods. If a dairy Harm is, submerged for twelve hours the effect is apparent on the milk production throughout the season, and -if the water lies for a longer period the pasture is probably killed. Knowing this from past experience, seeing his land becoming submerged during the flood of last winter, Mr Marchant hurried to Auckland and purchased ■a, big centrifugal pump. However, by the. time it arrived the water had geine down and the plant was: not installed. . Neighbouring farmers, became interested in the scheme and a small company was formed to take o'ver and operate the pump. With the prospect of a serious flood at the beginning of last month a start was made tq instal the pump. This took four days., and in the meantime about 400 of the 1000 acres in the island block became covered with wate.r. The flood-gates were only operating about 'four hours a day. On the fifth day the pump was started, and it worked for twelve hours. The next day it was kept going continuously, and the water level in the drains of the whole 1000 .acres was reduced to. midsummer level, despite the fact that the flood-gates were then not operating at all on account . of the arrival of the, flood-water from the upper reaches qf the river. The result was astounding. So overjoyed, was Mr Marchant at seeing the water rushing off his land at a rate estimated at 3000 gallons a minute that he stayed up all night wa,tailing the pump work. The plant was placed where three, large drains, converged at a flood-gate, and they soon became incapable of bringing the water to the pump fast enough to keep the ten-inch intake pipe full.

Simple calculations show that the pump is capable of lowering the water lying on 100 acres,, at the rate of oine inch an hour. H'ad there not been a pump most of the, pasture on the island block would now be dead and the country still too wet for cattle, as the result of the downpour oft the last days, of June. Now the land near the pump is the driest on the Plains, for a short run dajly lowers the drains- to summer level. The whole block would get the .'same advantage if all the drains were in efficient order.

It is confidently asserted that the use of the pump will mean, .an increase of production of the 1000-acre block to 20,0001 b of butter-'fat next year, and that this will go on increasing, as, instead of tihere being about six inches of sweet on the surface, the tact that the water level will always be kept low will mean that two or three feet of land will sweeten, for the surface will crack deeply and thus facilitate natural drainage. That the land is of the best has been proved in past years, when there was. no flooding. One such year a settler pastured 65 grown cattle on 90- acres - all the year round without anj r hay or. supplementary crop. COST OF THE SCHEME. The installation of the pumping plant has proved to be economically very sound. The pump will discharge 3000 gallons of water aj minute for 24 hours a day, and its capital cost was less than that of qne small floodgate, which in that locality will normally only function for a few hours daily, and in flood time, wh,en most required', not at all. It is reckoned that even if only one inundation I s prevented by starting the pump at the commencement of a stonn the whole of the capital cost will be saved.

The. cost of the pump was £llO, and the electric motor, belting, housing etc., did not bring the total above £2OO. The actual cost’of operation is, not yet known, as different motors have been tried. Mr N. G, McLeod, Thames Valley Power Board engineer, has assured the settlers that the cost will not be 'Anything ta worry about. The 25-h.p, motor now used will, consume about 15 units- of current an hour if kept fully loaded. The. charge will be l%d per unit during the day .and %d per unit’during the night. A' time switch may be us.ed to eps-ure getting the current l at the time when it is cheapest, and with a differently designed pump it would be possible to instal fin automatic switch which woiuld start and stop the motor according to the water level. EXAMPLE FOLLOWED. The marked success, ofl the island block pump has so impressed settlers that it is confidently iasserted that the drainage schemes of the Plains

will be revolutionised. Already another group of settlers has decided to have a pump installed as quickly as possible. This will be near the Ngatea brigde, to eliminate the chances' of the land on the southern side of Orchard East Road becoming flooded by water from the higher land near the Kei'epeejii-Kopuarahi road. Although it is desired that the plant should be made available for work as quickly as possible, the settle! s are profiting by the experience- of the island block group, and intend living thorough inves,tigtaions made as to the size and capacity of the; plant before purchasing. It is here thqt considerable difficulty arises, as it is impossible to estimate how much water will have to be dealt with. The rahifall, soakage, capacity of drains., head, and amount of syphon effect are factors that have to be takep into consideration when choosing the pump. To get. the most efficient machine it is desirable to get it designed for the particular work. As the effect of the scheme can more or less only be determined by actual experiment, it is hot desired to spend more, money than is absolutely necessary. Centrifugal pumps of the design required are not easy to obtain, and a pump not actually designed 'for a similar job would be inefficient and expensive to run. Much investigation by a competent engineer is necessary to get the best respite, and the settlers are very fortunate in having Mr McLeod, the Thames Valley Power Board engineer, interested in the project.

POWER BOARD’S PART. Undoubtedly it is to the interest of the Power Board to encourage its engineer to interest himsejf in the matter, as not only will the pump require electricity for motive purposes, but, if it is. a success, it will undoubtedly be the forerunner of many other pumping stations on the Plains, and’these will consume electricity at other times than .at the peak load hours, thus tending to 1 reduce the cost of power to all consumers,. A much more important aspect is that the production of butter-fat by all the farms benefited will be greatly increased, and sections may be. cut up into smaller holdings l , thereby increasing the demand for 1 electric power.

Mr McLeod met the settlers at Ngatea on Friday and went into the proposition. Afterwards he inspected the pumping station on the island block. The Power Board will meet to-mor-row, and, if it is agreeable, the engineer proposes to ascertain the most suitable size of pump and motor. Possibly the board will undertake the installation and running oil the station.

DRAINAGE BOARDS INTERESTED.

The Horahia Drainage Boa.rd iSi also keenly interested in the proposed pump, as it realises, that pumping could be. very effectively employed at otlw points in the area under its administration, and should the Ngatea scheme be as effective .as is expected, other pumps will have to be installed. The question whether the Driapage Board or the settlers should administer the ..proposed pump at the Ngatea bridge will be considered at the next meeting bf the board, and an assurance has been given by some of the members that should the Ngatea settlers go ahead with their proposal and the board later instal pumps, the Ngatea group will come in on the same basis. The economic soundness of securing protection from flooding in a country which on an average is only six inches above, mean sea level by means of electrically driven pumfcs seems to 1 have been established. A ; new era will open for the Hauraki Plains if the claims are only half subtsantiated, for with efficient drainage. at all times the soil will be able to show its amazing fertility, and the one and only drawback to .the district will be removed. The. progress of the s.cheme of pumping will be closely watched by the whole of the Dominion.