BOROUGH WATER SUPPLY

Bay of Plenty Beacon, Volume 08, Issue 91, 20 July 1945, Page 7

BOROUGH WATER SUPPLY

PROPOSED EXTENSIONS

MR R. P. WORLEY'S REPORT

The following report Avas submitted to the Whakatane Borough Council at its last meeting by Mr R. P Worley:— One scheme provides for a new gravitational supply from the Wainui Stream (Maraetotara) using the existing pumping scheme as an auxiliary. The reservoir would lie on the hill near the mouth of the gorge with a gravity filter plant about 15 feet higher elevation. With a 250 000 gallon resei'A'oir the preliminary estimate is £20,000. When the Wai- ! nui supply Avas not sufficient the existing pumps could be brought into pumping to the existing reservoir. The estimate provides for a 9" pipe to be laid from the existing 9" supply main at the intersection of Douglas and Alexander Streets, via Valley Roaf.l, to the new niter plant and reservoir. The connection Avould be on the upper side of the existing valve t . which Avould then be permanently shut. Water from the old. reservoir Avould gravitate to the neAV after passing through the filters. The reservoir capacity would then be the sum of the old and new say 150 000 gallons. Uscld as an auxiliary, there would be no sense in abandoning the old reservoir and building a new one of 500 000 gallons at; the gorge because the uneconomic pumping to a greater elevation than necessary would take place only in one quarter. The above estimate does not include the cost of the catchment area. The other scheme provides 10 1pumping from the. river, only Avitli new low lift pumps in triplicate. Ilocculation tank gravity filter, filtered water reservoir connected to existing pump 30'OUO gallons per and neAV 500,000 gallon reservoir at 240 feet elevation. If this source is retained for all the year pumping the above appears to be the minimum requirements. The preliminary estimated cost is also £20.ol>l> Avithout land. If 'the filter plant is omitted, in the meantime and the water ilocculatcd and settled only the cost could be reduced to £17,000. The settled water' Avould contain not more than 3 parts per KKMJOO of suspended solids, when . the river is at its, worst. Discoloura- : tion would be reduced to the same ( Idegree. That Avould equal about 4 petrol tins of silt from the 500,000 reservoir. The filtered water of , > 5 course, would have no sediment. s The gravity scheme appeals to me 1 for tlie I'olloAving reasons: (1) It Avill cost no more in capital cost; (2) It will cost very considerably less in annual cost; (3) it can be very simply extended Avhen required by installing another unit in the filter plant and pumping more frequently. The only apparent disadvantage is the low head about GOlbs •standing pressure. But in case of fire the old reservoir could be connected direct by opening the valve at Alexander Avenue. Until detail plans have been maiJe, it is not possible to make detailed estimates. The figures 1 have given above been prepared on the same data for both schemes and are therefore strictly comparable. If final estimates for one .scheme are higher or lower there would be the same difference in the other. 1 take it however that your Council does not wish to go to the expense of having both schemes worke'd out in Avitli Avorking draAvings from which exact quantities could be prepared. The comparative estimates given above are hoAvever, sufficiently accurate for the. Council to decide, which, scheme should be adopted.