Soil investigations by UNSRI students. in P8 12 S TC 11
On the way back.
Operation set on drainage.in TC 12 SDU side of P6 3N on 4 March 2005
The flapgate has been taken out.on 4 March 2005. P6 3N TC 12 SPD side.
This picture was taken in June 2004. P6 3N TC 5 SDU side
The same structure.
This P6 3N TC3 on SPD side on early February 2005
P6 3N TC 12 on 4 March 2005
This P6 3N TC 4 SDU side on 4 March 2005
Dam made by farmers in P19 2S Saleh in the SDU
Ths is the dam near P11 in the SDU of P10 2S Saleh on 26 Feb. 2005.
Some practical experience concerning : unripe soils, half ripe soils and ripe soils! Also the pyrite depth was investigated, using peroxide: noting the difference of oxidation for organic matter and pyrite: smell (SO2)and color (light yellow)
This area needs very urgent better water control. The pyrite layer was found below 70 cm and in many areas below 1 meter. By better water control, two times rice followed by maize in the peak of the dry season would be no problem. (no pyrite oxidation hazard by drainage and drier conditions).
This structure shows severe underflow under the box culvert according the farmers. Also some leakage is visible through the dam. Note that coconut trees have been cut in favour of rice cultivation.
According the farmers also this structure shows underflow under the box culvert.of the structure. Why the flapgate has been taken out is not clear.
This structure shows severe underflow under the box culvert, it is bending and farmers are afraid of collapse
On this picture severe side flow is also visible. Bags with soil have been washed away.here.
This structure was completely repaired in September 2003. Clearly the sideflow problem has not been solved.
This farmer has replanted already for the second crop and has put plastic sheets around his field to prevent rat attack later in the season.
The operation has been set on supply to enable pumping from the tertiary canal.(land preparation). This structure is withstanding a large water pressure. Main problem: side flow. and leakage through the dam. Note that also the connection of the pre-fab plates not completely fit anymore (irregular subsidence problem).Investigating the leakage problem we came to the conclusion that a sleeve on the bottom of the box culvert that fits the fibreglass flapgate would strongly reduce leakage through the flapgate.
The pipes in the dam have been set too high. But without flapgates set on supply, the pipes would show too much outflow during low tide when located deeper.
Also here the pipes are located too high and flapgates on the pipes are needed. The plan is that on 10 March the flapgates, using bags around the pipes (Bugis example) ,will be added and tried out.
.
|
Soil investigations by UNSRI students. in P8 12 S TC 11
Some practical experience concerning : unripe soils, half ripe soils and ripe soils! Also the pyrite depth was investigated, using peroxide: noting the difference of oxidation for organic matter and pyrite: smell (SO2)and color (light yellow)