Advantages and Disadvantages of ROR Hydroelectric Projects

HABITAT FRAGMENTATION

Habitat fragmentation refers to the emergence of discontinuities in a single habitat.
In other words, it refers to the division of a single large habitat into two or more smaller habitats.
It usually results from deforestation.
It can occur due to the following two reasons:

Natural reasons: floods, forest fires, volcanoes, etc.
Anthropogenic reasons: construction of roads, dams, forest land brought under cultivation, etc.

Implications of Habitat Fragmentation

Reduction of available habitat leads to the migration of animals into dense patches of forests.
Such migration creates competition among animals for prey, territory, water resources, etc., leading to the extinction of some species.
Moreover, there are greater chances of spread of disease among the concentrated population.
Small fragmentations with limited resources can support small amount of population only. Moreover, small isolated population is more vulnerable to fluctuations in climate.
The edges of fragmented habitats continue to expand due to human and natural activities.
Exterior portions of fragments become susceptible to the entry of exotic species. These exotic species may be invasive and may disrupt the existing ecosystem.

Solution to Habitat Fragmentation

A solution to habitat fragmentation is to leave a corridor or strip of forests connecting two fragments.
The corridors facilitate the movement of animals between fragmented patches.

RUN-OF-THE-RIVER (ROR) HYDROELECTRIC POWER PROJECTS

The ROR is a type of hydroelectric generation plant, whereby little or no water storage is provided.
The storage reservoir is referred to as pondage.
A plant without pondage has no water storage and is, therefore, subject to seasonal river flows.

Advantages of ROR Hydroelectric Projects

These projects involve minimal environment impact, because there is no large-scale storage of water. Storage of water leads to disruption in the aquatic ecosystem. Many plant and animal species submerge.
Water storage leads to the submergence of many villages. Thus, there is a need to rehabilitate large population. Such rehabilitation is not required in ROR projects.
The ROR projects do not obstruct river flow and are thus, permitted on international rivers.

Disadvantages of ROR Hydroelectric Projects

These projects are more suitable for perennial rivers and not seasonal rivers. During dry seasons, electricity cannot be generated in these projects. Advantages and Disadvantages of ROR Hydroelectric Projects
In India, these projects are more suitable on the Himalayan rivers which are perennial in nature and not on peninsular rivers which are seasonal in nature.
In these projects, adjustments cannot be made in the amount of electricity produced or plant load capacity, because flow of water is determined by nature.
ROR projects may cause habitat fragmentation, especially when transmission pipes are constructed to transport water over large distances.

DRAWDOWN TECHNIQUE OF DESILTING

Over a period of time, some of the silts brought by rivers from mountains are deposited in the water reservoirs and even on the river beds.
Thus, water reservoirs and river beds require regular desilting. Desilting refers to the removal of silt or sand deposits from water reservoirs, river beds, etc.
There are various techniques of desilting. The most frequently used technique is ‘drawdown’ technique of desilting. ‘Drawdown’ refers to the lowering of the water level in a man-made reservoir or tank (for the purpose of desilting). Advantages and Disadvantages of ROR Hydroelectric Projects
Drawdown technique is considered as an efficient technique of desilting. However, this technique obstructs the continuous flow of water.
Thus, this technique cannot be used, where minimal flow of river is essential to be maintained.

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