Our hydro rank indicates the areas throughout the world that are most rainy and least rainy. Areas with the most rain have ranks of 70% or above and drier areas have ranks of 30% and below. However, the amount of rain a location receives does not necessarily correlate with a high hydropower production potential.

The Amazon Basin, for example, has an incredibly high rank of nearly 100% across a large, flat area. However, the lack of constraining topography, such as narrow valleys, results in expansive flood plains. This makes building a hydro facility in this area impractical since the structure would have to stretch across such a wide area.

For this reason, areas that have narrow constrictions for water to flow through are better for hydropower development. In some cases, the area where a dam is constructed may actually receive very little precipitation. For example, the Aswan Dam in Egypt has a hydro rank of 0% and the Hoover Dam in the southwest US has a rank of 14%. What makes these areas perfect for hydro development is the way the terrain has constrained the movement of water from a large drainage basin.

3TIER’s hydro rank is truly a measure of atmospheric precipitation, to use this information to derive a hydro rank based on power requires combining this precipitation dataset with a digital terrain model. Our hydro rank can, however, be used in concert with our other ranks to investigate general climatological conditions at a site. For example, is your concentrating solar plant located where there is adequate water to drive your steam turbine? Using these ranks together is a powerful way to investigate weather driven renewable energy in different locations around the globe.