Currently, the classic hydrological mangrove Classifying Equipment of Watson (1928) is still applied and recommended. From extensive research in Malaysia, found that the species growing in the mangrove forests of Malaysia can be grouped into 5 classes based on three variables: tidal regime, elevation, and flooding frequency Areas in class 1 are inundated too often for mangrove species to survive, resulting in mudflats devoid of vegetation. In class 2 only pioneer species like Avicennia sp. and Sonneratia sp. can establish. Class 3 is the most diverse class, with hydrological conditions suitable for groups of species including Rhizophora sp., Ceriops sp. and Bruguiera sp‥ Class 4 is inundated by the tides only rarely and therefore allows other species groups to enter the mangrove vegetation composition, e.g. Lumnitzera sp., Bruguiera sp. and Acrosticum sp‥ The highest class, which is almost never inundated, is only suitable for mangrove species such as Phoenix paludosa Roxb.
Despite the wide application of Watson's classification outside Malaysia, pointed out some disadvantages of this classification for a more general application. The most important drawback is that Watson's classification is developed for regions with a regular tidal regime and a regular elevation profile. Found that due to an irregular tidal regime and micro-topography the inundation characteristics of a mangrove forest showed much higher spatial variability than expected. Inundation duration was, for example, longer than expected based on elevation and flooding frequency because water was ponding behind natural levees. Additionally, the tidal regime in the case study site in Vietnam was a mix of diurnal and semi-diurnal tides, making the variable "flooding frequency" unsuitable as a proxy for hydrological conditions.
With each year that passes Hydrometallurgy Equipment are being more widely used to recover base metals from ores and concentrates. Generally these processes involve liquid-solid separation of metal-bearing liquors from barren residues. This may be done by countercurrent decantation, thickening and filtration, or filtration or centrifuging only. Choice of method is governed by chemical and physical characteristics of the pulps; cost of labor, power, materials, and waste disposal; and even by the amount of capital available when building plans are under way. Since all these controlling factors change with time and location and with technological advances, the separation method must be re-evaluated when new plants or expansion programs are contemplated.