THE DRAINAGE ACT.

Marlborough Express, Volume III, Issue 112, 11 April 1868, Page 4

THE DRAINAGE ACT.

Ik accordance with the notice in our last, a public meeting was held in the Council Chamber on Monday last. For understood reasons it was adjourned from 2 o’clock (the advertised time) till 4 o’clock, when there was a full and orderly attendance. Mr. TTf.kry Dodsok proposed that Mr. Henry Redwood should take the chair, which was seconded by Mr. Moffitt. The Chaiemak, in opening the meeting, said they all; knew the object of their assembly that day,, and he -would read the advertisement. They were - well aware this was a very serious matter: —the overflow of the \gater of the Wairau. He himself was at a loss to offer any opinion as to the best r .measure that might be adopted for alleviatf ing the flow in the lower parts of the dis- : , .trict. He believed that something might be done that would have a beneficial: effect,, and he would be happy to have any suggestions from gentlemen better acquainted with the subject. Mr. Goman, as one of the promoters of that meeting, would inform them that they held a preliminary meeting, and came to the resolution- that it would be well to

provide that meeting with the opinions and advice of the best authorities they had, more immediately in connection with the breach. They asked the Superintendent if he would send Mr. Clark, in company with Mr. Dobson to the breach ; but, unfortunately, their notice to the Superintendent was too short to enable him to submit the matter to his Executive, without whose advice he could not comply. Receiving that reply, they had not thought it necessary to ask Mr. Dobson if he would proceed with Mr. Clark to the breach, and especially as Mr. Dobson already knew the levels and the locality well. He knew the lower part of the Wairau, and might give them a detailed idea what was best to be done to carry the water away. Their presence showed that no one doubted the advisability of something being done. What they did would never hinder a very large flood going over the land, only those usual floods. His own impression was they should keep the Wairau water in its own proper channel if they could. Plenty of people said that was impossible. He did not think that by cutting drains for the water after it had come down the Opawa, that it would preserve the lower lands. He considered the only way was to put themselves under the Drainage Act. Mr. Mopfitt, as one of those signing the requisition to assemble that day, would make a few remarks. At the preliminary meeting their object was to prepare some measure to lay before them for their consideration that day; but the shortness of the time prevented that. They would now get the statements of parties interested, and who desired action to be taken, if possible, to prevent the complete inundation of the country. Either they must continue to allow the Opawa river to go on as it was going, and render the land wholly useless for cultivation, or, they must take means to prevent it. To-day, they would consider the means necessary to prevent the overflow, and provide for the initiation of such means. They must take that matter into their own hands, as the provincial treasury was so low that they could expect no assistance from the Government. If the Government would provide any scheme for draining and for protecting the river banks, those people interested would take action for themselves. It appeared: to him there was nothing else could be done but to adopt the Drainage Act, of and the whole work would be in tEe handsof the Superintendent. In most places people assented to the application of money, and the Government saw to that application after. He would not express any opinion as to the course to he adopted for draining or dealing with the overflow of the rivers. He would leave persons who were more competent to deal with that part of the matter. Their first consideration- was to provide the money. They would have to be all assessed to provide a revenue. They would have to consider what extent of country should he included in the district. More or less all the land in the Wairau was affected by the floods. Lands at a distance were even affected, as their value for other purposes was diminished. If the town for instance were considerably submerged, and rendered unfit for general use as a town, the value of country lands would be disadaffected. But lands particularly benefited by improvements should pay in a greater proportion than lands benefited in a lesser degree. The Act provided for the •payment to be made, being in proportion to benefit conferred. The old Opawa Breach Act provided for payment first by the Government ; now they knew the Government were not in a position to give anymore, and they could not expect the half of the amount necessary. As he had heard farmers express that it would be almost better for them to pay a considerable sum of money, year by year, to keep the water back, thanhave things in the present state.

Mr. Henry Mears wished to ask Mr. Moffitt, as the Provincial Government were in such difficulties, if it failed, would their money be lost with it ? Mr. Moffitt could not say, as he did not come to answer any legal questions. Mr. N. Pritchard would like Mr. Alfred Dobson to give them his opinion, whether there would be sufficient fall by cutting through the rock, and the probable expense.

Mr. Alfred Dodsok said he was sorry that circumstances had prevented him accompanying those who lately went up to look at the river, that he might have known the recent course the channels had taken, to bo able to speak on the subject. But as to the actual course to be adopted for permanent benefit, he could not say that which had lately been the state of the breach would affect that. The Wairau river was liable to considerable floods from a rough mountainous country, bringing down a considerable amount of shingle, and from that circumstance the natural bed was in course of being materially altered from time to time. Large rivers in this country—whenever they come out of a mountainous, region—bring down shingle which: radiates

to form mounds or banks wider as it came lower down. The course of a stream varies from time to time by the raising of the bed by the shingle brought down. When the stream comes into the open flat country there is a tendency to the diversion of its course, and it overflows in various directions. Prom the overflow of the Wairau river, the land itself had been formed, and the height of the land depended upon the nearness of the channels at different times. The banks of the Opawa river were at a considerable height above the channel, and when channels broke out of the Opawa high ridges were on either side. It was difficult to retain the rivers in their channels, as the channels got raised, and from this cause there were diversions of the river from one course to another. In the course of 20 years ago, and afterwards, they found the Opawa not an active river, except in cases of high floods. The banks were so continuous with the adjoining land, there was no deep channel. About 1860 or 1861 a decided channel began to open at the Breach. When he visited it in 1861 it was about a chain and a half in width. Choking the channel then, by driving into it scrub, &c., would have caused shingle to close up, and would have prevented a deep cut from forming, but that was not done. Towards the end of 1861, the injuries to the deep channel became so serious that it was necessary to commence works more expensive than would have been necessary at first. He went up to commence some steps to stop the overflow of the river. It was not then suggested to close up the Opawa entirely, but simply to prevent ordinary freshes coming that way. There were two streams opposite the breach, as shown roughly in the plan he produced. He recommended a planked weir across the stream at the breach from 4 to 7 or 8 feet high, making it in a curve, that the first escape of the water should go over the middle. It was not practicable at that time to put it in as the river was too large. He had to attempt to push forward the Wairau stream so as, by increasing it to diminish the Opawa one, till he could get the work done. He tried to do that by two methods. The first was by cutting channels on the north side of the main stream, where there was a decided fall towards old channels of the Wairau. He had then cut as deep as would allow to afford relief. But though channels cut through clay or earth soon scour themselves out, in this different case disappointment was the result, as the water came down so fully charged with shingle that these channels in most cases filled up, that you could not tell where the channels had been. He attempted to produce the same result by jetties of manuka. Faggots were laid flat down, and secured by stakes driven some four or five feet into the shingle. The bushy part was loose at the top, to wave up or down with any stream coming over it. By the first jetty, which was two or three chains long, he gained a bank of sand for a chain aiid a half above and below the jetty, and nearly in height to the top of the brushwoik. The only part that was low was close to each side of'the brush. The effect of the brushwork enabled him to extend the jetty. In a very short time by that and other jetties, he has driven 1 the river so much to the north that the channel of the Opawa had only dead water in it two or three feet deep. He considered that the situation for the weir, to be of a permanent nature, should be lower down between grassy banks, and he proposed inviting tenders for sawn timber for the weir, which was to be put in with a floor below it to admit the flow of the water to pour on the’floor. The expense of the work (£1,800) was thought by the Government a considerable item, aiid it was considered desirable before going to: such expense to have further advice on the matter. The services of Mr. Fitz gibbon were secured, who examined the river for two or three miles, and he drew up plans. A scheme recommended by some then, is brought forward now, to put the Wairau river behind the rock above the Breach, with the idea of doing away with the difficulty. Those who entertain the idea should spend some time at the spot when the river was in flood, and they would then become aware that though the main channel of the river, which was an important one, abutted on the rock, yet to a great extent the water could not really be brought near it; but even if it were, there would not be the slightest guarantee to maintain the river in that course for two or three months at a time. Since 1861 he had known the main channel turn away from the hills a quarter of a mile. The river was a mile wide in parts about there,- and would require the same precautions-as below. In making the cutting, he believed the greater proportion would he through rock, as—judging from the appearance of the hills—there was on great coating of soil. Mr. Fitzgibbon considered it was quite undesirable, and that nothing would be gained by the attempt.

Mr. Fitzgibbon—at the instance of the Government- —drew out a design to divert the river from the Opawa by crib work. A different method was recommended by him from what he (Mr. Dobson) proposed. Mr. Fitzgibbon considered it essential that no water should flow over the dam. The’ water was to he entirely diverted into the "Wairau. He was well aware that after the dam was made, difficulties would arise to keep it in operation. The river might undermine portions, and he mentioned methods to keep it in repair. But he (Mr. Dobson) considered these were so expensive. It was easy to put crib work up, hut after it was put up there was no more guarantee against the water undermining it than merely a shingle bank. As soon as the dam was well in operation, he succeeded in shutting up the Opawa, but it was found that the bed of the river itself was a great deal higher. As they earned the dam higher the bed of the river rose. The timber work being of a very sloping nature, when they reached a certain height there Was no more width and they could not go higher. As soon as the water got over the dam, the work was destroyed in that place. By preventing the overflow altogether, they made no provision for raising those banks in proportion to the rise of the bed. The argument he would draw from all this was in favour of those jetties ; he had always found them stand under considerable trial. If put in a heavy stream they might be washed away, but as a rule, almost all those put up had stood several floods, and accumulated a bank of considerable width, even if the jetty itself was undermined and carried away. It appeared to him they should have some sort of weir, a sufficient stop to the bottom part of the channel at all times, and to admit the water to flow over it. It should be made in a substantial manner, and secured by a weight of boulders, and every precaution. It would also require a moderate expense for the lighter channels till a belt of bushes or plantation was got along that part of the river. By choosing projecting points, they would extend the channel by running a jetty out, and after each flood lay down a few chains more; as fast as they extended the bank, the water would make way on the other side. The expense of those jetties would not be a heavy item like that of a timber construction', and the breadth of the bank would be so great that a single fresh would not cause such damage, and during that time they would be checking the course wherever the parts 1 were most suited to the purpose. If the' banks were planted with willows and scrub and protected from cattle, there would grow such a network of vegetation as would take a great force to destroy. It would at first have to be fenced from cattle, and it would require a shepherd to' look after it. With respect to the drainage to get rid of the water coming down the Opawa, by completing Kelly’s ditch, which runs on the other side of the Bush, at present about sixty chains, it would require a cutting of nearly two miles to carry it from the Wairau to a bend of the Opawa, a little below Gordon’s creek, and nearly at the back of the Plough Inn. Such a channel if only made the size of the ditch was at present, he considered would be a benefit to the whole of the land below the cutting' on the Opawa, and to the land through which the cutting came. That land was so low it was almost impossible to make use of it. Along its banks the overflow would raise the sand to a height as would render the land available. He did not at the same time consider this would give general relief to the districts in the higher parts. The Opawa channel above the proposed cutting was so contracted that only a limited supply of water would flow down it. The flow at the Opawa bridge rises to the level of its banks, and if the flow islarger, there is only a slight increase of height there, because the surplus escapes before it comes to Mr. Robinson’s, and such overflow would continue undirninished still, or nearly so. 28,000 or 30,000 acres of land were actually affected by the overflows, but some of that was flooded from the Wairau- only! But 20,000 acres might be calculated to be actually benefited by that operation; which would give an idea of the amount requiring to be raised ; that would give £I,OOO, at B£d. per acre. Mr. Moffitt moved the following resolution : “ That the lands within the following boundaries be brought under the operation of the Drainage Act, 1867—namely, North of the WairauEiver, East, by the sea; South by the Awatere River ; and on the West by a line running from the junction of the Waihopai, with the Wairau, to the Blarich.” Mr. G. Dodson would like to hear some observations as to the working of the Act. Mr. H.- Dodson would second the resolution, and in answer to his brother, would-

speak to the manner of working the Act. He had listened attentively to what had fallen from Mr. Dobson, and he was quite correct in what he had stated of the effect of the jetties described. In frequent visits when the works were in operation, he was struck with the increased quantity of shingle thrown up under Mr. Dobson’s exertions. When Mr. Fitzgibbon first visited the Breach, the bank had been raised three or four feet, and Mr. Fitzgibbon said he would propose putting the crib-work on the top of it. To do Mr. Dobson justice, he knew that he held that a better position would be lower down, and not too near the run of the river-. This would have held the shingle, and raised a bank. It was an act of justice to Mr. Dobson to say he believed the brush-work was of material benefit. He (Air. Dodson) thought they should go nearer the sea if they wanted to do anything. They should shorten the course of the water to let it run as quickly as possible to the BoulderBank. They all knew the bursting of the Boulder Bank lowered the water when it was rising upwards. It subsided because it got a ready outlet to the sea, and fell two or three feet in an hour or two. To throw the water- rapidly towards the Boulder Bank, they would plan to increase the scour of the river, rather than commence at the top. Carrying out KejlyA drain worrld relieve that part of the country.,, Mf ‘would- narry -little‘'watei-' f 6 the flood that came down here, but it would grow larger and wider. Any number of people could request the Superintendent to bring the Act into operation over a certain area. The requisition would then be submitted to the Council, and it determined the matter, and the quantity of land to be brought under the operation of the Act. The powers under the Act were considex--able. If a district was once brought undertime Act, there was scar-cely anything that could not be done afterwards in the way of drainage of a useful character. The Act provided for rating, but it also determined that it should not be an average or area rate, but at various rates according to the advantages derived under it. Mr. G. Dodson would ask some questions. If the Drainage Act were brought into operation, how about those lands in Spring Creek that were not affected 1 Mr. Dobson had said the bed of the river was always rising.

Mr. Dobson had to thank Mr. Dodson for corroborating his remarks as to the success of those jetties, Mr. Dodson had said there were advantages in beginning below rather than above. Such a course depended upon the relation of the country. Those lands about the town were only 14 feet above the level of the sea, so that the inclination from here to the Boulder Bank was trifling. Between here and the Opawa Breach there was a rise of 80 to 100 feet above the level of the water here, so that any arrangement of that kind would not afford the same relief. The roughness of the channel above was a sufficient obstruction. The bed of the river did rise on an average, but if the highest floods were allowed to overflow the banks, the banks would rise in greater proportion than the bed of the river. Even if a constant expense were incurred, it would be well to go to that moderate expense in keeping a constant watch on the channel.

Mr. Collie said he ought to be competent to speak upon the subject of floods, for he had had general experience of them, (Laughter.) He had also given his thoughts to the matter years ago. It was utterly impossible for the town to do anything against the floods without the co-operation of the country, and he was glad to find farmers coming forward in favor of some general action. The plans proposed by previous speakers might be excellent in their way, but they were quite insufficient for grappling with the evil. He would give his general opinions. When a physician was called in to a patient, he first administered an emetic or a purge to clear the course before he attempted to work a cure. In this case too, it was useless doing anything to the banks unless they first cleared out the channel more or less. Whenever he had propounded a plan, he has been met with the reply, “ Oh, yes, but what a lot of money it would cost ?” Now, who that has ever achieved great things— Mr. Peabody, for instance—was ever deterred from making a start, by thinking on the ultimate greatness, and the ultimate expense venture 1 They had to get one general plan and carry it out gradually, to the amounts at their disposal -If they watched the course of our rivers, they would see that as they did not naturally run straight, whenever there was a bend or au inclination to one, the river had a tendency to deposit on one side a

quantity of sand of shingle, in gold-diggers’ phraseology, a bar. This had always driven the water over to the other side of the stream, causing a continual undex-mining of the banks and the breaking and washing away of the land. This was the great secret for the management of these rivers. The bars gradually increased, raising thenheads with each flood further above the water, and all kinds of vegetation grew on them till what was once part of the bed of the river was really now dry land. At the time of the Breach undertaking, our Govex-nment was raising up useless barriers on one side of the Wairau, when they ought to have been x-emoving bodily the bar at the other side of the river, which was shooting the water across. He laid great sti-ess upon this matter, as being the great px-inciple to be recognised in the management of all rivers like ours with banks of sand or gravel. It had been often said to him that thousands ot tons of shingle came rolling down in a flood ! How could it be otherwise, he would ask, when no attempt had ever been made to clear away any of the shingle, the deposit of ages, and each flood from the tendency already explained was scooping out fresh shingle from every bend of the stream. The banks of the Wairau were too low, and the bed of a liver in its natural state was never sufficient to carry away a flood ; therefore, after adopting the above precaution, an artificial embankment would .have to be made, but at a certain distance from the natural banks. He believed this was the best engineering opinion that could be got; it was that of the engineers whom the French Emperor sent to visit the Rhone and other rivers after some gx-eat inundations. In times of veiy great flood, if the water rose over the natural banks, it would have mox-e room by being able to spread as far as the artificial embankment. These artificial boundaries .would have to be raised along the whole course of the river, wherever from the lowness of the ground it was necessary. The whole of the distx-icts would therefore be px-otected indiscriminately, and no one would be aggrieved. Before they took any further steps to put the money into the same hands as had squandered away £13,000 before, they should know that some permanent and xxniversally beneficial plan was to be carried out. He held that they ought to do nothing, therefore, till some competent plan was decided upon. Mx-. Gorrie thought they ought to apply the Drainage Act. He would back Mr. Collie’s plan, provided the embankment was made of timber—(laughtex-)—as that interested him. Some had said they were not affected by floods, but what use would their grain be of, if the townspeople were swept out to sea. He approved of adopting the Act.

The Chairman said he did not think the Wairau would ever progress unless this Drainage Act was brought into operation, but it required to be nicely handled before being brought into operation. With the judicious expenditure of a few thousand pounds, great benefit might accrue. If they opened a free coui’se for the lower waters, they would not overflow us as they did now, A good canal might be cut out by tapping the OpaWa, and perhaps another neai’er Blenheim. They would then be relieved of those half floods, which did as much damage as larger ones. He thought the Superintendent would lay out the money in the best possible manner. The Chairman then put the resolution to the meeting, which was carried with one dissentient. Mr, Moffitt then proposed that the following gentlemen form a committee, to take the necessary steps towards having the Act brought into operation ; “Messrs. Henry Redwood, Henry Dodson, W. Collie, R. Matthews, Charles Eyles, J. E. Hathaway, R. Beatson, E. Paul, C. Redwood, and the mover.” With a vote of thanks to the chairman, the meeting terminated.