<P> Construction of a hydroelectric plant requires a long lead time for site studies, hydrological studies, and environmental impact assessments, and are large - scale projects by comparison to traditional power generation based upon fossil fuels . The number of sites that can be economically developed for hydroelectric production is limited; new sites tend to be far from population centers and usually require extensive power transmission lines . Hydroelectric generation can be vulnerable to major changes in the climate, including variations in rainfall, ground and surface water levels, and glacial melt, causing additional expenditure for the extra capacity to ensure sufficient power is available in low - water years . </P> <P> Once completed, if it is well designed and maintained, a hydroelectric power source is usually comparatively cheap and reliable . It has no fuel and low escape risk, and as an alternative energy source it is cheaper than both nuclear and wind power . It is more easily regulated to store water as needed and generate high power levels on demand compared to wind power . </P> <P> Dam failures are generally catastrophic if the structure is breached or significantly damaged . Routine deformation monitoring and monitoring of seepage from drains in and around larger dams is useful to anticipate any problems and permit remedial action to be taken before structural failure occurs . Most dams incorporate mechanisms to permit the reservoir to be lowered or even drained in the event of such problems . Another solution can be rock grouting--pressure pumping portland cement slurry into weak fractured rock . </P> <P> During an armed conflict, a dam is to be considered as an "installation containing dangerous forces" due to the massive impact of a possible destruction on the civilian population and the environment . As such, it is protected by the rules of international humanitarian law (IHL) and shall not be made the object of attack if that may cause severe losses among the civilian population . To facilitate the identification, a protective sign consisting of three bright orange circles placed on the same axis is defined by the rules of IHL . </P>

What type of soil is formed in water dam