Many projects were headed by loyal party leaders with no technical skills, which is another reason the canals were not more effective. Teachers, technicians, and other skilled (usually urban) professionals—hated by the Khmer Rouge as corrupting urban influences—were executed. Thus, primarily inexperienced and unskilled citizens, including the evacuated city-dwellers, were forced to work in the countryside growing rice and building these irrigation works, with rigid work quotas and hard, slave-like conditions. The lack of experience led to inefficient canals that occasionally collapsed in the rain.
Not only were the canals poorly constructed, but they also were built in straight lines, regularly spaced, at right angles along the 1-km gridlines of their military maps, ignoring hills, villages, and other topography. Some claim that many of the canals actually did more harm than good, disrupting natural water supplies and encouraging erosion. This pattern can be seen in most of these images. In more recent years, the irrigation system built during the Khmer Rouge regime is much less defined in satellite imagery.
It appears in the images that each district had to dig a certain amount of ditches, whether needed or not. Indeed, workers had rigid daily quotas, so that some finished early and some could never finish. There were strict decisions about which varieties of rice were acceptable, diminishing the diversity of varieties which had adapted to local conditions.
Though it is likely that by the end of the Khmer Rouge regime canal construction expertise had improved, the post-Khmer Rouge government had to devote considerable resources to repairing irrigation works. One official said 80% of the projects had been poorly constructed, though it varied by region.
Although many of the canals were poorly built, some of them can still be used. The Cambodian Prime Minister Hun Sen started supporting the re-digging of the canals in 2005, and now that the people who are rebuilding them are no longer under the Khmer Rouge, they get paid a small amount, and the crops that are harvested aren't taken away by the government.