C— 8.

For some years past the Department's operations have been equally divided between land development and construction connected with drainage, flood-control, and roading. As increase! farm production is the ultimate object of all these activities, they must be adjusted to the wai situation without impeding progress. Equal in importance to active new development is the problem of maintaining that which has already been created, and in this connection I have to direct attention to two matters of importance. These are the maintenance of the tidal stop-banks on the foreshore and river-mouths, and the maintenance of the improved river and stream channels. Two years ago a phenomenon having the characteristics of a tidal bore caused extensive damage to the stop-banks on the Hauraki Gulf and inundated thousands of acres ol land. The damage done to these stop-banks was not entirely repaired, and past experience has shown that the stop-banks must be periodically raised because they sink into their mud foundations. Overflow of these banks by a high spring tide this summer indicates that they require immediate attention. These stop-banks should at least be restored to, and maintained at," their original dimensions. Graphical comparison of the ~ 1939 flood stages with prior floods indicates some deterioration ol the recently improved river-channel. There is evidence of shoaling at bends and bank accretion, and the time has arrived when financial arrangements must be made for maintenance dredging. The rainfall at Kerepeehi in 1939 was 45-15 in. The average rainfall over a period of twenty-four years is 44-257 in. The wettest month was June, with a fall of 7-66 in., and the driest March, with a -fall of 0-46 in. . Rainfall records of daily precipitation at Kerepeehi, Hauraki Plains, since 1916 are as follows .—

Records of Daily Precipitation, Kerepeehi, Hauraki Plains.

Average rainfall over twenty-four years is 44*257 in. The following is a general review of the works carried out during the year : — Dkedges. One floating dredge and three bank-operating excavators have been in commission during the y No. 15 Bucyrus Brag-line Excavator completed Piako River improvement work 011 the reach between 12 miles 40 chains and 13 miles 15 chains in April, 1939. After an extensive overhaul carried out at the Kerepeehi depot, the machine redredged the Mangawhero Stream for a distance ol 65 chains from the Piako River. Since February this plant has been operating on a punt and constructing a stop-bank along the southern side of the Kaihere Road, where, owing to continuous subsidence of the road embankment, further protection against flood overflow is now required. In 1251 working-days the machine excavated 31-564 cubic yards of material at cost of is. 9-2 d. per cubic yard. The high unit cost is due to heavy expenditure on the complete overhaul of the plant. No. 16 Bucyrus Drag-line Excavator has been continuously employed widening the WaitakaruruMaukoro Canal, and during the year completed the reach between the State Highway bridge and the mouth and also, working upstream again, has partially completed the canal-construction between pegs om. and Im. Using a fyard bucket on 50 ft. boom, the machine handled 64,607 cubic yards of material in 224 working-days at unit cost of 7-3 d.

2

Number of Bays, with given Daily Precipitation in Inches. S § S S S § 5 | is § S § 9 Total Wettest Month. Driest Month. Year. m«'«'o > '- Days. Fall. s sssss°s\sssss 8 gSSSgS§'SS§§§ O i 6 O rH tH tH TH (N|(N CO -rf w o lqifi 100 12 9 7 2 3 1 .. i .. 1 .. .. 144 52-10 Nov. 6-65 | Feb. 1-05 9 7 " 131 11 4 4 3 1 1 1 156 45-61 Feb. 6-26 Jan. 0-65 9 8 ' 145 14 6 t . i - -- 1 "I 44-06 Oet. 7-47 May 2-24 \i\l " m 9 1 3 2 137 27-36 July 4-52 Pec. 0-89 mo 85 7 10 3 1 i 3 2 U2 43-16 Feb. 6-10 July 1-73 190? " 93 12 5 3 2 1 "6 34-43 Oct. 5-89 Feb. 0-72 ]IH •• ioi 17 9 3 'i l .. 1 133 42-81 Feb. 6-62 April 1-73 99I ■■ 151 6 5 4 1 1 1 169 47-04 April 9-76 March 1-72 1094. 100 8 10 5 2 5 1 1 •• 2 166 60*37 April 8*55 July 1*87 M2B 15 4 2 - 1 164 37-64 June 6-67 April 0-84 " 149 15 6 4 '5 2 2 183 55-53 May 8-86 Feb. 1-79 1W " 159 10 6 5 4 184 45-33 July 6-29 April 2-01 qIs 125 7 9 2 '3 2 2 1 151 47-30 May 7-52 Jan. 0-01 IWQ " m 19 8 3 1 155 41-05 April 5-09 Feb. 0-74 '• 4 9 2 3 " '2 '2 146 37-72 Jan. 6-87 Dee. 0-80 93? ' ill 10 7 4 " . . 2 167 43-23 July 7-80 March 0-98 " 126 7 5 'i 1 I 43 32 ' 05 Fek 4 " 95 N0V " °' 93 " \io io '1 4 '3 1 174 38-93 Feb. 6-54 March 1-20 ]lll ■ 1,8 n 6 5 22 " 1 .. 1 166 43-23 June 6-15 Oct. 2-05 1935 ' 163 15 6 4 2 2 .. 1 194 53-42 July 9-56 Jan. 0-93 1MB " 127 11 6 3 1 -.2 150 40-62 Feb. 5-83 May 1-63 " 7fi 21 8 5 'i 1 i i 114 45-51 May 5-89 Feb. 0-51 •' I4 19 13 6 4 2 1 2 101 58-43 Feb. 9-42 Oct. 0-84 \lll ■■ 9! 19 6 4 6 1 123 45-15 June 7-66 March 0-46 mo* :: 10 1 1 5 . : . 26 10.74 .Tan. 7-00 March 0.70 I I _J — * First three months of year only.