RANGITAIKI DRAINAGE

Bay of Plenty Beacon, Volume 4, Issue 156, 17 September 1941, Page 5

RANGITAIKI DRAINAGE

RIVER MOUTH PROBLEM SETTLERS CONCERNED OVER FLOODING

Settlers at Thornton, whose several thousand acres of farm land l are drained by the Kopeopeo Deviation by dredge canalls leading into the Rangitaiki River, are at preslent much concerned! over the inability of the Land Drainage Department to reduce the waiter level at the mouth of the river by cutting a new channel through the sandl- - Representations are to be made to the chief drainage engineer at Auckland to have a further attempt made to open up a new channel. It is contended by these settlers that much of their land has been water-logged and rendered completely or partially useless in recent months because the dredge canal and its tributary, the Massey Drain, have been running almost bank high, thus giving very little "freeboard" for the drainage of adjacent lands. Heavy rain in July, August and September has filled up the low places on these farms, and surface water lias not been able to get away to sea, because of the unduly high level: of the Rangitaiki . River near its mouth. ' Where electric flood pumps are discharging water from farm drains into the dredge canal, it has been noted that there is a considerable seepage of water back from the canals. Attempt to Cut Through Sandspit In July tlie Land Drainage Department raised the hopes of these: Thornton settlers by transferring to the river mouth one« of its Ruston B'ucyrus dredges. This dredge commenced cutting through the sandspit with a view to giving the pentup Avater of thei river a quick getaway to sea. Unfortunately, weather conditions, did not favour this work.

A cut about a hundred yards long was made fro,lll the river to highwater mark. Everyone waited for rain in the back country and, a consequent "fresh" in the river as a means of sending the water through the new outlet straight to sea. Nothing happened. There has been no "fresh" in the river. The Rangitaiki still turns at right angles and wanders down the beach, for a mile before it meets the! sea.. The water in this lagoon or estuary backs, up the dredge canals with every tide, and drainage of adjacent land is thereby made impossible. Apparently Abandoned Apparently the Land Drainage Department has given up the task of opening up the Rangitaiki River mouth for the time being. The dredge has been sent back to its previous work on the Eastern Drain, which drains into the Orini Creek and the Wliakatane River. While settlers at Thornton realise the difficulties at present facing the Land Drainage Department they do not consider that the Department has tackled the serious problem of keeping the Rangitaiki River mouth open. Elver since the Rangitaiki outlet was dredged in 1914 the departmental engineers have had.ideas fca keeping the river mouth open. Small, groynes of piles and willow] posts have been constructed to confine the river to* the. straight and narrow way through the sand-hills. In spite of this the river has swung away along the coast, and the mouth has been blocked by a sand-spit. Silted Up Two, years ago thei Department dredged a cut through the sandspit, but almost immediately the new entrance silted up and the river turned towards Whakatane and built up another sandspit.

It is recalled that the 1 late Mr F. J. Reynolds, whose Thornton farms drain into a dredge canal, took measurements in his drains to show the considerable difference 1 in the water level caused by thei opening up of the river mouth. Mr Reynolds used to advocate that settlers should make representations to the Minister of Public Works to have the river mouth improved by the construction of groynes.

This, he contended, was a work of national importance, and one that ought to be carried out by the Public Works Department and be paid for out of the Consolidated Fund, rather than be carried out by the: Land Drainage Department and be paid for by the drainage ratepayers of the Rangitaiki Plains. Earlier Scheme Recalled 1 A settler who worked for the Land Drainage Department when the Ran-

(Continued in next column)

gitaiki Outlet was being made 27 years ago, relates that the last quarter mile or so through the sandhills was cu,t away with scoops, as the Prestman dredge coukl not excavate in sand. Part of the engineering scheme w r as to confine the river through the sandhills by means of wooden piles and a timber wall or

sheathing. Riles and timber reached the site, but only a few piles were driven. For some reason, or for no reason at all, the scheme was not completed. The river was left to its ctwn vices, and the piles and timber used up for bridges on the Plains. It was a costly blunder, for the river has eaten into the sandhills, and evaded away until it has formed a wide shallow estuary. A similar problem exists at the mouth of the Tarawera River, where groynes of rock had to be built to prevent the river from returning to its old course in front of the township of Matata. A Job for the Future It is probable that when the war is over the Government will have to tackle the job of doing something permanent to make the Rangitaiki go straight out to sea. This will certainly be a costly business, but the whole future otf the drainage of the Rangitaiki Plains depends on keeping the entrance of the river clear. Settlers state that the the water at the Thornton and Edgecumbe bridges is now higher on the bridge piles than in former years, shoAving how the river has silted up at the mouth, causing Avater to back up for some miles. One settler Avent so far as. to declare that much land near Thornton has been Avetter this Avinter than it was 20 years ago>. This is not surprising, seeing that in those days the riA-er went straight out to sea, and scoavs Aver© able to enter the riA-er and load cargo at the ThornIton bridge. Now even small boats cannot enter the river. ;