Flood

Floods, which result from pluvial, fluvial, and oceanic factors which eventually cause the submergence of land not usually covered by water and where “stream flow is characteristically turbulent” can help us define what a flood is and the visual features that we should expect with a flood. Visually speaking, we should expect one of two situations when observing a waterbody that will be labeled as a flood. The first one is the case of a waterbody with a “muddy looking appearance and being brown or red in color” due to “particles, carried by the stream, are called the stream’s load." Within the steam, “in the main part” the particles are larger and are responsible for this color and are known as the “suspended load” [1].

When a stream or flood loses the velocity to carry these particles, these particles are deposited, meaning that the murkier floods are more powerful and able to carry particles further. When viewed in a natural setting, floods appear to be either a larger, murkier rapids when the flood is taking place, or after the flood as a river that has overtopped and inundated nearby buildings, objects, transportation and other infrastructure, leaving the infrastructure “often damaged, and creating specific challenges for emergency response” [2].

Another flood case is one where flooding is less intense, and water, while moving quickly, does not move quickly enough to carry sediments. Many images of flooding that we view are pictures taken in urban settings, and oftentimes in these photos, floodwater will not be opaque and act more like a thick film that appears to move at moderate speeds over these settings, particularly roads. This is not to say that this less opaque, lighter flooding cannot happen in more rural settings, as it can, but that it is more common and relevant to our project to view flooding that occurs near infrastructure.

References

[1] Tulane University. (2016, October 17). River Systems and Causes of Flooding. Retrieved (2021, July 21), from https://www.tulane.edu/~sanelson/Natural_Disasters/riversystems.htm

[2] International Federation of Red Cross and Red Crescent Societies. (2021). Hydrological Hazards: General Floods and Flash Floods. Retrieved (2021, July 21), from https://www.ifrc.org/en/what-we-do/disaster-management/about-disasters/definition-of-hazard/floods/