During construction the observational method is a continuous, managed and integrated process of design, construction control, monitoring and review enabling appropriate, previously-defined modifications to be incorporated during (or after) construction. The objective is to achieve greater overall economy, without compromising safety.
Filter used on a skimmer for removing oil floating on water. It allows hydrocarbons of varying densities to pass through the filter whilst repelling water. However if the head of water acting on the filter becomes too high water will pass through it.