The Rivers Question

Hawke's Bay Tribune, Volume XVI, Issue 7, 19 December 1925, Page 5

The Rivers Question

Diversion of the Ngararoro ADVANTAGES OF “THE PINES” SCHEME. OPEN LETTER TO SETTLERS. The following is written bv Mr J. A. Miller, a member of the Hawke’s Bay Rivers Board, for the information of settlers and others who ar© directly interested in the schemes for the diversion of the Ngaruroro river as a precaution against floods. Erom Fernhill the Ngaruroro has an almost straight course towards the sea in an easterly direction for three miles; it then bends in a southern direction towards Pakowhai. Adjacent to this bend are “The Pines,” and from this bend is the old course of the Ohewia stream (now banked across), a continuation of the almost straight line from Fernhill to the dip at the Waiohiki golf links (on Pakowhai-Waiohiki road). From this dip looking towards Fernhill, the bend (The Pines) is 1J miles distant, and in this 1J miles there is a fall of over 14 feet. Looking down the dip towards the sea there is a further fall, into Moari land, in 50 chains of another 8 feet, and, from this to the sea at the Washout, a further fall of 24 feet. In all a fall from The Pines to the sea of 46 feet 'is 6| miles. This course to the sea is miles shorter than the present course, or than Mr. Hay’s course. OVERFLOW AT THE PINES. Mr. W. Nelson suggested this route many years ago. In 1911 Messrs Laing, Mason, C. D. Kennedy and J. B. Thompson, reporting, recommended an overflow above Pakowhai bridge, but provided a'spillway or overflow at The Pines and one above. In 1919 Messrs Fulton. Furkert and Hay in their report commenting on the diversion of the Ngaruroro at The Pines (then joining with the Tutaekuri) stated: “This scheme is very tempting, if the plain could be considered in a virgin condition but when the actual channels necessary were considered in relation to the extremelv valuable land which would thereby he converted into a river bed we were reluctantly compelled to cast this out.” But later Mr George brought forward his scheme re diversion of the Ngaruroro river at The Pines taken past Alien’s, and joined with the Tutaekuri at the overflow, the combined rivers then being taken to the Waitangi. These channels were found not to be so costly, and the valuable land myth was blown out. The Board has 170 acres at Pakowhai which if sold would more than pay for any valuable land taken bv the new route. In 1923 Mr. Hav met the Harbour Board to discuss Mr. G. Nelson’s reclamation scheme and when Mr Nelson unrolled his plan showing the diversion of these rivers (Ngaruroro from The Pines!. Mr Hav pointing out this scheme on the plans said: “I consider this ideal engineering for the rivers. Everv engineer who has come to report of Hawke’s Bay rivers consider this the most ideal scheme; it is a question only of cost.”

A cheap criticism—cost. Mr. Hav states definitely he has never taken out the cost nop has he attempted to do so, approximately or otherwise. Mr. Hav has twice voluntary informed me that Nelson’s scheme was the only scheme to deal with the Ngaruroro, once on the Fernhill bridge and the second time on the Pakowhai bridge. ,

Now our suggestion is a modified Nelson’s scheme. That is. we take only an overflow from the Ngaruroro at The Pines, such overflow being the surplus flood waters that the present channel cannot be made to take in an abnormal flood which might happen sav once in 25 years. This overflow will be down a practicallv natural course (for most of the distance the channel is already there! through the lowest and least valuable land, and bv the shortest route to the sea, saving miles. Tn this scheme it is proposed to make use of the banks to be erected for the Tutaekuri diversion, but increasing t“ie distance between these banks to take the extra water. The Tutaekuri is to be diverted nearer the bridge than in the <f G” scheme. The point is a ouarter of a mile further from Taradale, and will be nearly 1? miles distant at the nearest point from Meeanee. The levels from The Pines to below the golf links show 46 feet down to 34 feet, then for about 20 chains un to 38 feet, a sudden fall then to 32 feet, a fall of 14 feet in 11 miles. On the south side of the dip and its continuation there is high country at a level of 43} feet, with a steen drop into the channel. This channel from the 43 feet level on the south side to 40 feet level on the north side is over 10 chains wide, and the depth is below the 32 feet level—thus showing an amnle depth of over 11 feet and with sufficient to take 80.000 cusecs. These figures are taken from Messrs Fulton, Furkert and Hay’s 1919 report, and. if correct they show Mr. Hay that there is no truth in his remark that the 43 feet land would have to be taken into the overflow. We propose usinm this 43 f<*et land to retain water in the channel.

MR. HAY’S SCHEME

This scheme provides for an overflow between Pakowhai and Whakatu bridges on the Napier side, running into th© Tutaekuri through most valuable country with dwellings. It crosses a main road, and requires 640 chains of new and very high banks. It means a further 360 chains on the south side of the Ngaruroro and the raising of the present short bank at Whakatu. It also means th© raising of the Twyford and Raupare banks from The Pines to Pakowhai, a further 280 chains, and the balance of the increased distance on the north side of the Ngaruroro from Pakowhai to the sea, making in all 1480 chains, while “The Pines’’ route will only require at the most 400 chains of banking, having on each side high land and a channel in existence for most of the way. with no disturbance to a main road. LAND REQUIRED. .Mr. Hav requires 600 acres in addition to the valuable land he disturbs in erecting banks on the south side of the Ngaruroro, through closely settled, built on country through Clive township. The Pines route, including extra land for the additional width of the Tutaekuri requires 575 acres, less 126 acres owned by the Board, leaving a total of 449 acres to be acquired. The land required for Mr. Hay’s scheme is th© highest and most valuable in the locality, and on it are several residences. and it is the only safety zone for stock in time of flood. The hind required for “The Pines” scheme, though a small part is good farming land, is low-lying wet country. A comparison in values of land would he roughly 600 acres Mr. Hay’s route £32,000. 449 acres Pines route E 17.000. Mr. Hay’s course is around the high rim of the saucer. The Pines route takes a shorter cut from the rim to the bottom of the saucer. Mr. Hay says the whole Ngaruroro river will come through at The Pines, yet states that the whole river will not go through his overflow. Why ? The land is as solid at The Pinos as al Pakowhai. and if a scour would take nlaee at one place it will at the other. In The Pines scheme it is suggested to construct concrete sluices i«> save such erosion. Mr. Hav provide- for none at Pakowhai. The Pines overflow will lollow a gentle curve dirr< Ito sen. Mr. Hay’ • overflow run into th.- new Tul.i.(Continued 6 m xt column).

kuri (unless it breaks its 10 feet banks on the Whakatu side and sweeps through Clive) at an angle and impign on the north bank of the overflow with the danger of breaking it and both rivers sweeping down to Aleeanee and Napier. Air. Hay’s scheme brings the flood waters down to the congested part of the river at Pakowhai with banks on high ground on the Pakowhai side with danger to Twyford. Ran pare and Pakowhai on the Hastings side;

The Pines route relieves the river of much flood water before it arrives at the congested part, and thus no need for further banking on the Ngaruroro from The Pinos ro the sea, which is the shorter route.

QUESTION OF SHING LT

If shingle will accumulate at The Pines, is it not more likely io do so on lower levels with less veloeitv with all its obstructions; as at Whakatu and Pakowhai? We know that the accumulation at Whakatu is rapidly increasing, whereas at The Pines residents sav the river bed is lowering. The Pines scheme allows for 80.000 cusecs to travel down the present river channel, this, with the fall there, will give sufficient velocity to prevent shingle from depositing in any quantity. It is only an overflow in times of abnormal floods that is to bo provided.

Another great danger under Air. Hay’s scheme is the trapping of shinele above Fernhill. The river there is 90 feet above Hastings with only about 9 feet between land and water level. If the shingle is trapped surely the bed must rise. Air. Hav contradicted the chairman when he suggested these groins would deepen the river, yet he said thev would not do so and acknowledged that the river bed would build up. Concluding Air. Aliller says; “I strondv advise the ratepavers of Twyford. Raupare and Clive to voice their opinions on Air. Hay’s scheme, and let Hastings as well as Napier and Aleeanee give it their most careful attention. So that mv constituents of No. 3 ward know where I stand, T definitely state that I will oppose it to mv utmost ability.”