This station has a series of experimental and spawning ponds. Within recent years (1971, 1973 and 1974) it suffered from flooding. The following suggestions are being offered to help solve this problem:
(a) Earth fill with dirt the roadbed halfway from the main highway to the eastern corner of the pond complex (Figure 16 a-1).
(b) Raise (earth fill by hauling using dump trucks) the eastern dike, mainly inside fence (Figure 16 a-2).
Note that it is not necessary for the fill by trucks to reach the end of the dike. Its farther end can be filled from dredge spoils from the creek as indicated (Figure 16 a-3).
(c) The earth fill for the southern dikes (Figure 16 a-4) should be taken from the creek spoils and mainly placed on the dike outside the fence.
(d) The vacant lot (Figure 16 a-5) should not be allowed to be diked for impounding otherwise the northeastern corner of the station will be eroded by velocity of water from the creek along the road.
(e) The main creek and contributory creeks east of project should be cleaned and dredged.
(f) If possible, have a regulation enacted to prevent encroaching into existing creeks which tend to constrict original waterways. No regulation to this effect seems to be in existence at present.
(g) The chicken wire installed within the ponds seems to be ineffective because the top portion of the wire is lower than the present perimeter dikes or bunds. Hence any flooding over the perimeter dikes will necessarily be also over this wire fence. It is also observed that the bottom of the wire fence is not securely anchored through its whole length thus allowing entrance, and exit or mixing of stock. If screen wire is to be used, it should be installed so that its top portion will be higher than the highest observed floodwater. This can prevent fish faom getting out or coming in but the station stock will mix.
Using nets over the ponds does not seem advisable due to expense and operations and maintenance involved. Modifications of the dikes as suggested are deemed better to provide more permanent solution to the flooding problem.
(h) It is further recommended that a large enough sluice gate be installed to allow water rapidly into the pond system during high floods. This will provide quick balancing of water pressure on both sides of the dike.
(i) A long-reach hydraulic excavator, dragline or clamshell can be suitable equipment to use in the excavation of the creek and raising of the southern dikes. The equipment may be barge mounted if necessary.
FIGURE 16 a
AU TAU FISHERIES RESEARCH STATION
FIGURE 16 b
CROSSECTIONAL VIEWS OF DIKES
AU TAU STATION-HONGKONG
