AKAROA COUNTY COUNCIL.

Akaroa Mail and Banks Peninsula Advertiser, Volume VI, Issue 599, 11 April 1882, Page 2

AKAROA COUNTY COUNCIL.

A meeting of this Council wag held on Saturday. Present —Messrs Baker (chairtniui), 11. R. Bradley, J. Gobbio, G. R. Joblin, J. Boleyn, and Pottigrew.

MINUTES, ETC.

Tlio minutes of the previous meeting , were read and continued, and leave of absence granted to Mr Fleming, on Mr Bradley's application.

REPORT OF LAKE ELLESMKKB COMMITTEE. The Chairman said the first businesawas the report of this committee. Mr Joblin said he had a little more cvi denoo to put before them, which would finish the record, lie would read it.

[Held over till next issue.] Mr Joblin then read the following report from Mr Watkins, the plans accompanying which wore laid on the table for membei'3 to examine :—

Duncdin, March 23. 1882, G-. R. Joblin, Esq., Chairman of Luke

Eliesmere Drainage and Kailway

Protection Committee

Sin,—l beg to present to you the following report and accompanying plans (four in number).

PLAN NO. 1.

A plan of the estuary of the lake, showing tho position of proposed works, and a few of tho natural features of the place, also position of district road to Leeston and liakaia. Tho mouth of tho lake is shown and position of shingle spit. From this it will bo seen where tho water from the ocean comes into the lake. This plan is made from observations taken with a, prismatic compass, by means of a very short base lino and very acute angles, but the distance along tho mouth of tho lako was chained.

SOUNDINGS,

This plan shows soundings taken across lake at Fisherman's Point, tho position of proposed work:.- , . The sound ings arc taken with accuracy, tho cliainagea by means of a prismatic compass, and aro therefore oidy approximate.

BORINGS.

On plan No. 1 are also shown borings as taken on the spit at mouth ol! lake by Air Hardy Johnston, M.I.U.M It is probable that tho borings after t'io iU'tft Hue would be tliO same, but that chiy would bo mot with at a level Kovoral tt;ot higher, as this part of tho laKo has not been subjected to the same scouring that has occurred at the mouth, and from observations taken and evidence adduced from fishermen and others, who say that there is hard clay a few feet below the bottom of the lake, cis they have driven stakes for the nets.

Shingle is met with for a few feet deep on the shore side of the lake.

CLAY BANK.

As there is a clay bank where the fishermen's houses are, and clay is observed several feet deep on the face of tho bank, which is exposed for about & mile, it is more than probable that clay would be found a few feet below bed of lake at Fisherman's Point and at proposed works. SECTIONS ALONG SPIT AT MOUTH OF LAKE.

No. 2 plan shows longitudinal and cross sections along the spit from tussock to tussock, distance over half a mile. The level of lake on sth February, 1882, is shown, also height the water was corning over the spit into the lake at high tide, with the wind blowing off the land. This was 12ft higher than the present level of lake, and about sft above the level of the railway rails. PLAN NO. 3. No. 3 plan shows proposed regulating weir, with self acting flood gates to allow the water from the lake to flow into the enclosure, and thence into the Ocean ; the gates dose as soon as the tide turns and runs into the enclosure. They are adapted to drain to low water of Pacific Ocean. The. top of the flood gates are 9ft 6in above low water line of Ocean. The height of high, and low water are taken from assuming level of lake at lowest to be about half tide ; and from borings by Mr Hardy Johnston who states high water mark at 10ft below shingle spit at the mouth of the lake (not at the tussocks). From the fishermen I gather that at the point I mention, the spit was generally the same height, seldom higher, this is about 11*3 feet above present level of lake. PLAN NO. 4. Plan No. 4 is fully described under beading—Works of Improvement. WATER IN LAKE ELLESMERE. I shall first refer to water from the ocean. I observed the water from the ocean flowing into the lake on the sth Feb., 1882, at a height of over 10ft above high water mark of sea, for half a mile wide at the mouth of the lake at Taumutu. I questioned several of the fishermen at Taumutu, two particularly, one of whom has been 16 years at the mouth of the lake ; they stated that the water from the ocean often flows into the lake, generally soon after the lake has run out; this is always the case when the mouth of the lake is again filled up with shingle and the spit reformed, then it comes over in suffi ciant quantities to raise the lake from a foot upwards. More water comes into the lake in south-west weather than at any other time, more in the winter than summer, and the longest time that has ever been known to elapse without the water coming over in large quantities, is five months. Observations taken when the lake has settled show it usually comes over at least four times a month in quantities equal to the amount on sth Feb., 1882, the day observations were taken. Mr McVinnie stated that he had known tho water from the ocean to raise the lake 2ft in 24 hours from observations taken when the water had settled. This evidence is confirmed by information collected by the committee of the Aksiroa County Conncil, which evidence it ia not necessary to repeat in this report.

WATER FROM RAIN, RIVERS, ETC.

With reference to water from rain, rivers, creeks, and other sources. As I have not made- sufficient observations to speak definitely, I shall therefore refer to observations and reports from other sources. Mr Hardy Johnston, M.1.C.E., reports as follows:—'"The area of the basin drained into tho lake is about 750 square miles. The principal channels are the rivers Selwyn, Hart's creek, L 2, Halswoll, Irvvell, and Kaituna. The quantity of water discharged l>y these into the lake (excepting tho Selwyn) is continuous and almost uniform throughout the year. Although the drainage area of the Selwyn alone may be taken at nearly two-thirds of the whole basin, yet its discharge is not so great as that of Hart's creek, or even the L 2 river. Taking the flood line of the lake at four feet above high water of sea level the quantity of water accumulated in tho lake is 19,939 millions of cubic feet."

RESULTS

1 I wish to draw your attention to the following results :—l. Assuming the Selwyn to discharge one-third of the water from theso river sources into tho lake ; and secondly, assuming the Selwyn to discharge one-fourth of the water from the same sources. One-third of 19,939 millions of cubic feet from Selwyn is about G,G23 millions of cubic feet, leaving about 18,21)2 millions of cubic feet discharged into the lake from other sources, with a drainage area of 250 square miles. This is equal to 22 inches discharge over the drainage area ; being more than the discharge for the ruin fall (see rainfall and discharge). (2.) Secondly, one quarter of 19,939 millions of cubic feet for Selwyn discharge is about 4.984 millions of cubic feet, leaving about 1.4,954 millions of cubic foot to be discharged from these other rivers. This is equal to a discharge of 34 , 7f) inches, which is 21 more than the discharge from rainfall over this area. (See rainfall and discharge.) RAINFALL. fn the absence of observations by me, I shall refer to Meteorological observations at. Christchuroh. The mean average rainfall from 18G4 to 1877 was 25-72 inches, DIRECT EVAPORATION, ABSORPTION, SPRINGS AND DRAINAGE. On average ground it is usual to allow one-third of tho rainfall to (low off at once, one third to sink into the ground to reappear as springs to form watercourses, and one-third to soak into tho ground, to be absorbed and evaporated from the ground. Now, in tho case of the hills at Gobbie's Valley, K. ; ,:Luua, and there abouts, it ia probable that more than onethird flows off at once ; probably over a hn.lf, as tho ground is liilly ; the other half lo bo divided, part for otroams. arid the remainder for absoption and direct

evaporation. SKMViTN. On tho Solwyn it is probable that more than one-third disappears, to appear in springs and watercourses, as it runs over a voiy porous bottom of shingle, and it is a known fact that springs oil water about a mile away are affected by the river Sohvyn changing it:s coarse. It is exactly tho same with the liakaia and other rivers. There is an instance in Germany whore the water is known to appear four miles away, with a ridge intervening ; it wan proved by experiment. As the artesian supply on the lower ground is probably derived from such sources, and Haifa Creek, and perhaps several others, are said to be very little affected by the and to run

with about the same amount of water all the year round, it is more than probable that the rain from the drainage area of the Selwyn appears in the streams and artesians. One inch of rainfall over the whole drainage area of the lake is equal to 6£in rise in the lake. Suppose one-half of this water came into the lake, it would be less than 7ft in twelve months, and allowing 3ft for evaporation, would leave 4ft. (See Evaporation.) EVAPORATION. In the absence of observations at Ellesmere, I shall make a few remarks. The amount of evaporation from surfaces of water exposed to the natural effects of the open air is greater in summer than in winter, and is greater during winds than calms, The total amount of evaporation in several parts of England and Scotland is stated by reliable authorities to average from 22in to 38in ; at Paris 34in, Boston, Mass., 32in ; many places in the United States from 30in to 36in. The following is an extract from an article published by the Society for Promoting Useful Knowledge :—" Winda powerfully promote evaporation, because they bring the air into continual, as well as into closer and more violent, contact with the surface acted upon, and also, in the case of liquids, increase, by the agitation which they occasion, the number of points of contact between the atmosphere and the liquid. In the temperate zone, with a mean temperature of 52| degrees, the annual evaporation has been found to be between 36in and 37in. TEMPERATURE. The average temperature at Christchurch for the years 1864 to 1877 waa average 53*3 degrees. This is more than the temperature referred to for evaporation. WINDS. In the absence ot observations, I shall again refer to meteorological observations at Christchurch. The following gives the number of days from each point for the year 1877, the only record I have :—N. 4, N.E. 128, E. 28, S.E. 13, S. 7, S.W. 149, W. 11, N.W. 25, Calm 0. As the N., N.E., and N.W. are generally dry winds, they will greatly assist evaporation ; this gives 157 days from these three points. Of course all the winds are not dry winds, but, again, several of the others are dry winds. The south-west wind is often charged with moisture to a great extent, but winds unaccompanied with rain assist evaporation to a very great extent, even if charged with moisture. CATCHMENT BASIN, ARTESIAN SUPPLY. As there is artesian water in the vicinity of Lake Ellesmere there must necessarily be a catchment basin with pressure at the back so as to force the water above the level of the land ; it is known to appear at a height near the edge of the lake of at least 20ft above floci line of the lake, it is therefore probable that some of the water from this catchment appears as springs under tiie lake, this is near Tauinutu and elsewhere. Supposing this conclusion correct, it is again more than probable that a quantity of water finds its way into the sea in the same manner. IRRIGATION. As the ground about the Selwyn is of a nature that quickly absorbs water, it is probable that part of the water that comes from springs, arteslans and rivers is used for irrigation, and that in a few years the water of the Selwyn will be stored and used for that purpose. In the instance of the Selwyn, when the river has shifted its conrse, the crops on the side where the Selwyn flows are usually better than on the opposite side. Many settlers along the river have been known to complain about the water washing away the banks, but several have stated thut they prefer the river to run on the side where their property is. as they get better crops. Part of this information I got from Mr Lunn on my first visit. STORAGE OF SELWYN WATER. I enquired from Mr Lunn and others if it was probable that the Selwyn water could be easily stored for purposes of irrigation. He said he was of opinion that the nature of the ground where the river comes through the valleys and gorges, could be made available by means of an embankment for that purpose.

AMOUNT OF WATER IN LAKE.

There is at present three feet of water in the lake above the low water line of lake the last time it run out, and the top of the railway rails are 6£t 6in above present level. The lake is known for a certainty to have been more than a foot above the rails. The wash line at Tamutu carefully taken is eight feet above present level of lake, this is equal to from 10 feet 6 inches to 11 feet of rise of water in the lake above low water line of lake, and as the fresh water from rain, rivers, springs, etc., is estimated at 4 feet per annum after allowing 3 feet for evaporation ; there is therefore a rise of from 6 feet to 7 feet of water in the lake per annum, which must come from the sea. This entirely agrees with the evidence taken by the committee of the County Council, also with the information I collected during my visit at Tamuta and surrounding districts. The works proposed will have the- effect of keeping this water from getting into the lake, and at the same time provide means for the drainage of the lake to below high water mark of sea, or at least to as low as present level, probably several feet lower.

SCOUR. The flood tido in bringing the shingle from the ocean, has to raise it from a lower to a higher level, or in other words, has to work against gravity, while the ebb in dragging the shingle from a higher to a lower level is assisted by gravity. The largest amount of back water will be in operative if it has less than what may be called the effective velocity, or that required for acting on the material which forms the bottom. A sudden flood could remove what the same or a much greater quantity of water would never affect if liberated more slowly. The following table will explain what I mean, it is calculated from Sir John Leslie's formulse (proved by experiment by him. 3in per second—o'l7o miles per hour, will just begin to work on fine clay Gin per sccond=O34l miles per hour, will lift fine sand ♦ Bin per 0*4515 miles per hour, will lift sand as coarse as linseed 12in per second=o'6Bl9 miles per hour, will sweep along fine gravel 2£t per second—to 1 3638 miles per hour, will roll along small pebbles lin diam, 3ft per second=to 2"045 miles per hour, will invcep along angular stones the

size of an egg ( G's6ft per second—to 4*472 miles per bour, [ required to scour gravel. ' This is the result supposing the stream to be lin in depth. If the mouth of the

estuary be open, the quantity of water passing into the enclosure would be about two millions of cubic feet each tide. The area Ido not know exactly. The following table shows pressure and velocity of water from enclosure through the shingle spit, from low water to level of embankment :—

Pressure in Height Velocity in feet cwts per in feet. per second. square foot. 1 8 -55 2 11-3 Ml 3 13-9 1-67 4 16 2-23 5 18 2-78

6 19-7 3-34 8 23 4-45 10 25 5-57 12 28 6-86 15 31 8-36 20 36 11-14 From this it will be clearly seen that the water passing over the spit would easily scour a channel. It will probably be the sea that will start the channel, and the water from enclosure will soon scour it out, SHINGLE SPIT AT MOUTH OF LAKE. I am of opinion, after carefully considering the subject, that a channel between the sea and enclosure will be kept open sufficiently to drain the water in the lake, bo that it will never rise above high water mark of ocean, as every time the mouth or channel is open, for even two or three tides, it will drain to several feet below high water mark, and as the lake will only rise 4ft in 12 months by the fresh water if it were all confined in the lake (see rainfall and evaporation), and as the sea will break over the spit at the mouth of lake and flow into the enclosure, from whence it must escape into the sea again as it cannot get into the lake ; when it escapes it will open a channel through the spit and the water from the lake will drain out by every tide when the mouth is open. With reference to the success of the scheme it is only necessary for the month to be opened for 14 tides during the 12 months. Of course when the mouth is open the higher the water is in the lake the quicker it will flow out. as all the water above high water mark will flow whether the tide is high or low, but when the water in the lake is below high water mark of sea, then it will only be able to flow when the sea is below high water mark, The lake has been known to lower several feet in 24 hours, when the mouth was first opened, but when it flows so quickly it is beoause it is above the level of the sea. Thus some 4ft of water in the lake which I say would run out in 14 tides, would run out in about a quarter of the time if it was four feet of water above the high water mark of sea. WAIKEWAI CREEK. The Waikewai stream that flows into the proposed enclosure will, in my opinion, fill the enclosure several times while the other waters would fill the lake once. This alone would be sufficient to break a channel through the shingle bank, and act as a means of draining the lake. So that as there are two forces at work to keep a channel clear, it is only reasonable to suppose that the lake will be drained to the very lowest, by utilising the ways and means that nature has provided. Whereas these two sources, the Waikewai stream and the sea, have greatly assisted in filling the lake, they can now be utilised to drain the lake, so that what was once a source of danger will be made use of as a means of protecting the low lands of the lake, by providing means to assist the drainage. WORKS OF IMPROVEMENT—EMBANKMENT. The proposed embankment is shown on plan No. 4. I recommend that it be made acoording to the drawing ; this shows it to consist of piles and sheet piling as a protection to the embankment, which is to be made of cl?iy ; the sheet piling will prevent the water in the enclosure from scouring a channel under the embankment and where there are piles, there will be bracing through the embankment _to strengthen and hold it firmly in position. : The embankment is to be made to keep the water from the sea from getting into the lake, and to an approach for the roadway over the Weir. It is to be clear of water at low water mark of lake, so aa to have the whole area of waterway available for flood gates; but it will have to contend with pressure of water from the sea. It is made strong enough to contend with all the waves that are ever likely to affect it. The full force of the ocean waves will never reach the embankment, and this will be seen by reference to plan No 1. Supposing the mouth of the lake to be clear of shingle for half a mile, even then the waves would break against the high clay bank and not against any of the proposed works, co it is entirely free from any direct action of the waves.

WEIR WITH FLOOD GATES AND BOADWAY. On plan No. 3 is shown regulating Weir with flood gates in 20ft spans with two rows of floodgates each sft by 4ft 6in; six in each 20ft span, giving 135 square feet area. The piers to consist of a row of three piles 18in in diameter, driven into the ground equal to the length out, the pier to have a stay pile at the back, also 18in in diameter, and the span of 20ft to have two extra piles 6ft Bin apart. Sheet piling to be driven along front of flood gates, the top of sheet piling to be on a level with low water mark of sea—in front of the bags of concrete —to be laid to prevent a hole being scoured. Sheeting to be placed above the floodgates to top of roadway." The roadway will be at a height of about 15ft above high water mark of sea, protected by a handrail on either side. PROTECTIVE WORKS LAKE SIDK OF BANK. On plan Ho. 4 is shown the proposed protective, works to keep the surf from the ocean from coming into the lake across the spit for a few chains not enclosed by other proposed works. The greatest distance northwards from the proposed enclosure that the surf has been known to come over is about one mile, and only in a very few places over this, as the tussocks are growing most of the way. Past this mile the surf has never been known to come over the spit and it widens out from a quarter of a mile to over a mile. The proposed works along shingle bank are to be erected at a height of about 16ft above high water mark of sea, and for half a chain to over a chain back from high water mark along bank, so that they will not have to counteract the force of the waves but only the surf, also to stop the water from percolat-" ing through the shingle into the lake. The shingle from the sea will gradually form a bank nearly to the top of the proposed works, or at least to the top of the highest surf line ; the waves will always break before reaching these works, and will therefore soon run into the sea v again.

The works are to consist of two rows of fjpiles sft apart and spaced every sft, the sea side of the back row is to have sheeting for 'half the length of the pile and the front row to be only partially closed ; - the piles are to be cross braced. It will probably be necessary to fill in between the piles, but this will be allowed for in the estimate. These works to be erected as shown on plan No. 4. POSITION OF WORKS. I recommend the position of woi*ksto be at Fishermans , Point, in a southeasterly direction, across the estuary, so that the prevailing winds may be taken advantage of to assist in draining the lake. The floodgates will take up the whole «€ the water area of the estuary and the embankment will be placed at both ends of the * weir with floodgates, as shown on plana No. 1. ... I am of opinion that the scheme will I be a great success if carried out according ■k $o the plans herewith. BR* ESTIMATE. .

Charles Edwin Watkins, engineer. Mr Joblin spoke in support of the report. He thought the greatest credit was due to Mr Watkins for the trouble he had taken. Hart's Greek could be led into the 200 acres, if'there were not sufficient scour. Mr Hardy Johnston© had estimated the cost of keeping the sea out at £88,000, but he bad calculated on making the embankment where it would have to resist the full force of the waves. He had been told by *» Mr Montgomery that Sir J. Coode had recommended an embankment as the way to drain the lake. The speaker spoke at some further length on the scheme, and alluded to the " letters of Mr !F. Gread, saying he had no wish to rob him of any credit in the matter, for, as he had alredy stated in that Council. Mr Gread had suggested the place where the embankment should be placed. Mr Gebbie said a great deal of what w4s in the report and evidence they had known previously. He did not believe that Hart's Creek brought down more water than the * Selwyn. The main question to his mind, however, waa, Would the water in the 200 acres be sufficient to keep the channel to the sea open? Without the channel to « the sea being kept open, the flood-gates were useless. The Chairman saw no reaeon to believe that there would not be quite sufficient scour from the 200 acres, aided perhaps by leading in Hart's creek, to keep the SHOuth open.. Mr Gebbie Raid the Council were greatly indebted to the committee and Mr Watkins ** for the trouble they had taken. The next step he supposed would be to submit the project to-the Government, for the Council had no money to spend. Mr Joblin said that the Council should "" appoint a deputation to wait on Government, to urge upon them the importance of the scheme, If it were merely forwarded it would be no use, as it would probably be she' ved. The land that would be drained would repay the Government a hundred fold if the scheme were successful. If the Government were not prepared to undertake the scheme, he was in favor of » asking them to give the Council the land .and let them do it. He thought it was the Council's duty to endeavor to rescue such a large area from the sea, and so add to the counties prosperity. Such a * scheme should have a fair trial. Mr Gebbie objected to the Council undertaking the work. To do it they might have to sell the land before it was drained, at one-tenth of its value. The Government should undertake the work. Mr Joblin said the Government might make a mistake as they had before. For two successive years the railway works had been injured,. showing how ignorant the Government were as to the proper course to be pursued, and he declined to entirely trust to their mercies. The Chairman then proposed " That a deputation, consisting of the Chairman and Messrs Joblin, Maeefield, and Boleyn, wait on the Minister for Public Works, to lay before him the evidence collected by *. the Lake Ellesmere Committee, together with the plans, report and estimates prepared by Mr Watkine, and to request that if the Government think favorably of Ihe project, the work may be undertaken with '**■ as little delay as possible." Seconded by Mr J. Gebbie.

Mr Joblin proposed as an amendment the addition of the words "or that the work may be delegated to this Council," The amendment was not seconded and the resolution was then put and carried. Hβ „ MR COOP'S SCHEME, w Mr Gebbie laid on the table some plans proposed by Mr Coop of a barrier formed of piles, timber and planking, to be placed on the same site as the proposed embank

inent, the cost to be £2608 10s. It was decided to acknowledge tho m receipt of Mr Coop's plans. MB BARNETT'S NOTICE OF MOTION. Mr Barnett's notice of motion,— ,. That the following resolution passed at a meeting of tho Council, held on Nov 26,1879 :- *' * That at any time any money is allocated to the Okain's Bay Eoad Board, that the cost of regrading the Summit Road as described in the last resolution be charged against that Board , be rescinded, lapsed through his absence. CORRESPONDENCE. A letter from the Solwyn County Council was read re best means of lowering water in the Ahuriri lagoons and asking what wf lands would be benefited. After discussion, it was moved by Mr Gebbie—"That, in reply to the letter from the Selwyn County Council, the Clerk be instructed to write lo the Little River * Road Board for the necessary information as to what lands would be benefited^ etc. . Seconded by Mr Boleyn and carried. From the same, recommending new boundary between the counties, as suggested by the Chief Surveyor. Proposed by Mr Gebbie, seconded by

boundary between the Selwyn and Akaroa Counties, as recommended by the Selwyn County Council in their letter of Ist April, 1882, as follows,' That instead of the creek from Cooper's Knob, the northern boundary of sections 1060, 1452, 1267,1268, 1046, and 18,810 be adopted.'" ACCOUNTS. Accounts amounting to .£42 9s 6d were passed for payment. EXPENSES. Mr Gebbie proposed: "That the sum of £9 be voted to defray the expenses of the deputation appointed to wait on the Minister for Public Works." Seconded by Mr Pettigrew. Mr Joblin moved as an amendment: -" That the deputation appointed to interview tho Minister for Public Works on the iLake Ellesmere Reclamation and Railway Protective Works, be paid their travelling 'expenses. Seconded by Mr Bradley. The amendment on being put was lost, Messrs Joblin, Boleyn and Bradley voting for, and Messrs J. Gebbie, Pettigrew and the Chairman agciinst, the latter also giving his casting vote against it. The resolution was then put and earned, the members voting in exactly the same manner.

ADJOURNMENT. The Council then adjourned to Tuesday, 23rd May, at 11 a.m.

[Description of Work. Quantity. Rate per foot. Total. i — w Begulatingweir, with roadway and floodgates Embankment, with roadway Protecfionworks along shingle spit * •Feet ; & a £ ■ 660 10 0 6,600 ■ 660 i I 3 0 1,980 ] 1760 I 1 15 3,080 1$ per cen >r cent.,..., 11,660 Contingencies, 7 neering 2J pei it, engi1,166 Grand 1 total 12,826