J. T. THOMSON'S REPORT ON TAIERI FLOODS.

Mount Ida Chronicle, Volume II, Issue 75, 15 July 1870, Page 3

J. T. THOMSON'S REPORT ON TAIERI FLOODS.

(Communicated:)

.Tjie disastrous floods,on ...tbe Taieri Plains have, within" the last few-weeks, fad to a Ions: and interesting report from Mr. J. T. Thomson, Chief Engineer of the Province. In this .report Mr. Thomson unhesitatingly; .ascribes the: Hoods to the silting up', of the . bed of toe river, thereby diminishing th>e channel necessary to convey the flood w'ifer to its natural' outlet—the sea. Tbis-siltin'i-up of the river bed Mr. Thom : I soil in his report dogmatically'attribute?' I

to the inflow of itTje tailings produced bv the workings at the Hyde. Ha milt cD, ""'owburn, and the Serpentine, and offers yfirious as'to the ■ works which will be found necessarv dither entirely .to counteract the effect , of these floods, or re-' duce the damage to be apprehended from them to a minimum. Toe works, however! proposed by Mr, Thomson' are of su-h magnitude as to be entirely beyond the resources of the.. : Provjn e To consider this report .of the Pro-' vwinl lSn;:>,meer a .Select .'Committee of the Provincial Council was appointed,, who after havinsr taken a vast amountof evidence.' endorsed the opinion of j\fr. Thomson as to the ori^lr:

of the floods, they disapproved. • of various surest ions,of t);e Engineer as to thevbestreisedy for the evi~j. and failed to offer any of their* own to meet 'the difficulty. : . . ■ , . Adniitttpg, as I do, the-ability of Mr. " son's and • reeo:rnisin!>' the and. professional knowledgereport displays, T v cannot in an v \va.r 'agree - with tTie' r contusion. at which gentleman' arrives. Indeed 1 foe! necessitated, to talve- . except ion at the very premises upon whi; 4 ,h the report is based; and am v com pelled to cal 1 in fj uestion its! i eiitire

I ur© ;aiid the which lie arrives/ It must, I thiuk/be. evident to anyone ronversaiit with tt»e I subject;, an 4 acquainted withtbe localihties, that, however correct the interest' j iiiijf and elaborate caknilations which the report contains may bo, the' document must have been.drawn up bv. aoijie one wiio obtained Ms i nformation, not from personal inspection and knowledge, but •from; that most unreliable of all sources nearsay—or, wdrsc' still, salf-conveived opinions and foregone Ooni-iusions.' 1 In the first |'>iace, the assertion thai the floods are caused by the. tailing \vhieli .are discharged into the Taieri | river from, the workings at I Hy.de, Hamilton • and . other places | is simply' incorrect not one par-1 j tide of the tailings from either one oi' j these places having so far found its way i into the river. It is true that ti efertaiii | amount of earthy substance held in ' suspension by the water which has be< j n

used lor sluicing reaches the Taieri, but the tailings are deposited on the flat ground long before-the polluted ■ water reaches the river. In spite, therefore, of Mr. Thomson's theory that the Taieri river, fro;n its source to the s.ceue or the flood is a mountain torrent, which /would carry in suspension aud not deposit, auy substance contained in its water uutil 'its arrival at the Taieri Plain, where it becomes sluggish, I have no hesitation in asserting, that by far tiie least impetuous portion of the river is that w.hch receives the outflow of tail water from the principal workings, and. terminates in the Taieri Lake. So slight indeedis the eurrento: the river through tue lake as 10 be imperceptible, giving" it the appearance of a portion of the lake itself. W oiild 'it not, be reasonable to suppose "that the silt, in--stead of being carried down by the :

river, (which afier issuing from the lake resumes the character of a torrent) a distance of a hundred miles to the.TaieriPlain, would be deposited, and remain, uuder the placid, waters of the lake'.' • Admitting, however, for t' e sake of argument that a certain amount of si:l. produced by the workings, the polluted | water of yyhich finds its way into the Taieri—and taking into consideration the comparative amount of the polluted water so discharged auto the river, the depth of the river itself, and the le lgth of its course beibrc : reachingthe Plaius (the scene of the floods complained of); it must'be evident that the dissolved earthy substance which would be deposited along such a length of riverbed as 150 miles would be bat mfinitesimal and in the extreme, and not ouly not likely to produce, but abr solutely incapable of producing the immense amount (it any) of the damage and' mischief attributed to. it. Air.

Thomson .in bis report • further allude* of tbe Taieri and : Wauk>ri lakes and. ascribes their so doing to the «ame cause,as the flooding 7 of tlio Taieri Plain. Does Mr. Thomson not remember a. theory advanced by himself some years back, and .endorsed oy a number-of scientific genjlemen fhnt the Mauiototo and other large j plains were originally •inland•• Likes which-had gradually .been silted up, bv pluvial action, leaving the plains as t* e} now exist. ..If that .theory, we re correei i. con;ess 1 «-aun-1- see no reason why the same actum which caused thr" ;iisappear;tiice of the large iiiiaiiu -lakes, should not be si ill in operation, an v i riduaily ('ft'eetirig f a sirnikr-result bo ;■ a •■it VV.aij.ibri and the Taieri; far m« re probable do I co:.s : ier sued a solAiioh or thepresent ''phenomenon than in/ one which Mr. Thomson has thought fir to advance. As with Waihola and vVaipori so with the Taieri or Mauiototo Lake, where the same silting up process '.s plainly to be distinguished-r-a process which will, in-the course of a \evy few years, add a large amount..iof acreage.to -Ue terraJirmu ol' the .plains. Again. ;3 it Unrbasohable tojsuppose- that the •Lest ruction ;»y fire and euhiyaiion, nnc onsoliuailoii by tue feeding of stock of an immense amount of the vegetable '.natter which was formerly accumulated ■:>\\ the .earth, and led to the stagnation upon, and absorption.by, the ground of a huge quantity of snow and rain water which nowiiuds an outlet into the.river —carrying with it amass of earthy substance, not only from both banl-.s of the river along "the'lso miles of course towhich- I have referred, but along its entire kngtb (even to its very source) ;—much more likely to produce in ' the low country heavy floods than the nere polluted water of one, two, or three insignificant diggings ? I think ->o f and! think that reason and common .House will confirm me in my opinion. -C willingly admit that under either cirHimstiiuce the i\ suit is the same ; still unfair to attempt to important interest with causing evils with which it is not, unless in the most infinitesimal degree chargeable. Ido not say that no-, effort should be made to save the beautiful and fertile, plain of the Taieri from present danger and prospective annihilation; but I' do say that, if my hytaesis be correct, and the injury has arisen, not from the influx of tailings from the various diggings, but from the causes which I have enumerated, then ?ueli plans as those of Mr. Thomson for fhe damming up of the river at the outlet,of the Maniototo Lake, and regulating the supply in flood time, would be only adding another to th:- already too long list of useless public works, and casting where so much public money has gone before—into the water. I throw out these hints for the consideration of the Government, believing what I have asserted to be facts, which admit of absolute and ready proof, and 1 trust that the Government, before taking action either upon Mr. Thomson's report,,or that of the Select Committee,' will act with such caution arid prudence as will not only satisfy, them of the true tacts and state of the case, .but prevent them from the commission of an act which cannot fail to be useless to the public, but which will reflect dishonor and contempt upon themselves.