Hawke's Bay Herald. SATURDAY, JUNE 26, 1897. RIVER CONSERVATION.

Hawke's Bay Herald, Volume XXXII, Issue 10645, 26 June 1897, Page 2

Hawke's Bay Herald. SATURDAY, JUNE 26, 1897. RIVER CONSERVATION.

Now that the excitement of the record reign celebration has expended Itself It 1b time to attend to the serious business of the dally wants of the oommnnlty and the problems which affect the welfare of the district. Having aided in the loyal demonstrations, let us return to the most Important business which demand* attention. The recant flood disaster nooentnated the attloles whloh appeared in these columns before its ooonrrenco, and thongh the magnltnde of the power to be combattod was demonstrated beyond all anticipation, and in a measnre ealonlated to dishearten the confidence of settlers Id their ability to cope with it snooessfnlly, nevertheless the lessons to bo derived from the occurrence should be accurately reoorded and measures taken to mlnimlio the possibility of Us recurrence rb well as to reduce the evils to whloh it haß given rise. It mnst be evident to all the residents of the Hawke's Bay plains, as well as to the Inhabitants of Napier, that If floods ocour]again they will have to cover a higher level of ooantry, as the plain has been raised by the deposits of the last disaster, and with an equal amount of water the surfaoe must rite to a higher level in corresponding inorease to the rise of the ground over whloh the fbod will have to Bpread. Therefore there la an looreased menace to the townships, bridges, roadi, embankments, and .'dwellings whloh remain at their [former level. It is also evident that nnlees some process for scouring out the old beds of the rivers Is resorted to there will be no Beourity against the diversion of the ilvera into new channels of their own eeleotion, and they will not discriminate as to tltloß, ownership, or boundaries of the lands they tuko possession of, without the aid of nrbitratloa or oompens&tioa nader the Pabllo Worka Act. Apart from this, bnt along with it, Is harnessed the question of providing drainage to prevent the plains from reverting 10 the morass condition in whloh they were discovered by early Bettlers. Then we have the lnjaty to public works and the cost entailed by floods cm the malntenaeoe of roada and bridges, which Is only accessory to the preservation in onltlvable condition of our farm lands and security to the farmer against repetition ol dinastrouß losses of crops, It la nob tor us to enter Into suggestions of engineering methods for dealing with the difficulty, The preliminary meetingo of settlers have already appointed a committee to promote the formation of a oentral Elver Board to manage this matter, bub let us not forget how great has bean the loss to this district by abortive engineering woiks dealing with isolated areas. Experience has shown that the adoption of designs whloh may have proved successful ati come plaoes oiinnot be relied on to prodnce Buooess uuder different conditions, and many failures may be charged without doubt to the inauffioiency of engineering data In regard to the magnitude of the power of the waterß to ba plaoed under control, and of the numerous other elementary considerations whloh enter Into questions of large engineering works. All of these have to be weighed, measured, aud provided for with mathematical certainty to ensure the result) which tho works aro proposed to attain. Io a new oountry, with its limited resource!) of recorded information, its laok of population, and pressing needs for capital, it waa to bo expeoted that worka of large scope might be Imperfectly engineered from want of data, but in the advanced position of affairs at the present time, the command of labor, trained surveyors offering in all directions, and with more perfeot maps and scientific records of obaervatlom of ollmate and rainfall taken at numerous stations, it Is now posaible to acquire aoouracy ofi data about our rivers and their notion at a moderate expenditure! Let us point out that there should be no niggardliness In supplying an engineer with data, for on that will depend the whole of bis calculations t and the buoobbs or failnre of his work, and provided he has the mathematical genius to pnt his faots into figures he oould then properly adjust the strength of tha various parts of hits deeigna to the strain they wonld be put to, and there would be no need to think hereafter with sorrow of the proverb •• a chain is no stronger than its weakest link." Mnoh of the loss In the past haß been due to tampering with engineering designs which, like a rat hole in a river bank, may destroy the cohesion of the whole structure, and the difficulty of readjusting a design to balance all parts In correspondenca with some pettifogging variation may involve calculations as perplexing as the whole original work, and any neglect to apply them may act an the rat hole, The finance of the matter will be an affair for legislation. The area subjeot to flood oannot ba less than 40,000 acres on the plains of Hiwke'a Biy alone, and even throwing off halt this area, as either nse' less or fairly secure, ib 1b hardly too much to aay that on the remaining 20,000 acres there wonld be an average Inorease in annual rental value of £1 par note, an compared with what it is worth to-day, If it were rendered seoure from floods. To obtain this advantage of £20,000 per annum it is surely worth while to provide a scheme of works and rating powero even at an expenditure of several thousands a year. Although, If the money were borrowed at the low rates of interest now ruling the burden would be hundreds, not thousand!), of pounds, It U always interesting, If the Interest Is of a somewhat melancholy nature, to note how others laboring uuder similar misfortunes propose to grapple with their difficulties. The watershed of the Hunter river, in Now South Wales, h enbject to periodical floods, and there, as here, the work of protection has been dona plaoetneal, with the reverse of satisfactory results. In response to an appeal from the settlers tha Government eenb Mr Price, Assistant Engineer of the Pabllo Works Department, to report on a soheme of river conservation. His report emphasises what we have repeatedly contended for in these oolnmns — that any work, to be effactnal, mnst fltart with tho months of the rivers, It Is utterly useless to ereot i banks or Boonr out beds of rivers np oountry if tbe mouths are left like the neoks of bottles. Whether it would not also be advisable to shorten the ohannels, to allow the water to get away quioker, involve* a question ot expense with whloh only engineers can properly deal, and we do not presume to offer any opinion on that question. Bat Mr Prloe oame to the oonolußlon that no system of embankments, or of opening the mouths of the rlverß, would deal with the enormons rainfall whloh occasionally oooura in the West Moltland district. One soheme, Involving tho cutting of a large and deep oanal, he rrjeoted on aooouut of its cost, put down ab over £1,000,000. Tbe plan he favored was, in addition to embankments and clearing the mouths, an immensereservoiror catchment area in tbe upper reaob.es of tbe river, It will ba remembered that In a letter to the Herald after the late flood Mr Goodall, formerly engineer to tbe Harbor Board, suggested such a plan for Hawke's Bay. Without professing engineering skill, we venture to doubt whether any reservoir which could be constructed In Hawke's Bay would hold the extraordinary rainfall which had to be ooped with in April. Even if it conld the expense would be enormoun. In his report on the Hunter river and its tributaries Mr Prloe suggested a huge reservoir, or artificial lake, ab a suitable slbe ab Wood* lands, about ten miles below the Goulburn Junotion. The oolossal nature of the undertaking may bo judged by the faob that to raise the water level ab Woodlands by means of tho proposed dam to a height of 180 ft) above summer level would, writes Mr Piioe, "submerge over 33 square miles of plain, and would back np the Hunter and GouJbum fivers for ten aad

eight mllas respactlvely above the junotlon near Danman." This, unfoituaatoly, would flood the township of Denman, " whloh woald have to be removed to higher ground," observes Mr Piloe. ThU woald, however, be Rn ndvantage, a« the towniblp la now completely submerged daring high floods, whloh iweep honses away and oaune loss of life. The maximum oapaolty of the proposed dam is estimated at 40,000,000,000 oublo feet, and the greatest) depth of this Immense body, covering 35 aqaaie miles, would be 130 ft. As Mr Prloa remarks : "It is hard to realise suoh an Immense body of water as 40,000,000,000 oublo feet. No artlfiolal teaeivolr In the world at all approaches 111," In a word, the proposed reservoir would be 23J times larger than the Prospeot Reservoir, whloh supplies Sydney with wster. Mr Prloe sets down the estimated cosb of the woik at £550,000, and point n oab that as the whole country will benefit by tbo proteotlon afforded to the railways a large proportion of the cost of the work Bbonld be undertaken by the country at large, Tbls is a point that should not be lost sight of In dealing with liver conservation in Hawke'a Bay. We understand that it will coat the Railway Department some £30,000 to make good the damage In Hawke's Bay by the late flood, and the department) should contribute liberally to any plan whloh would proteob the line from future damage. We are not, of oouise, unseating any each eoheme heie as Mr Prloe propose! In New Sonth Wales, The cost would put lb utterly out ot the question, We merely mention it to show how others are prepared to grapple with the evils of excessive rainfall. Here, we believe, the problem will prove much timp'er tn solution. But when our settlers ace how othors similarly situated are prepared to fight against future disaster it thould give them heart to do likewise, and nob to bU down and saplnely give up the stinßßle.