Life’s gain to earth’s drain: Flooding in Santorini

Water is necessary for all life, yet if not properly prepared for; it can, in excess be destructive, both physically and economically.

When most people think about flooding they picture houses and cars partially submerged after a massive event. While this does happen, flooding on a smaller scale happens on a daily basis all around the world. In Santorini specifically, abundant rainfall during the winter of 2018 overwhelmed the natural paths for water dispersal which caused the excess water to destructively carve its own path. The examples of flooding in this blog will be from excess rain, focusing on what happens in urban and natural environments.

In urban environments the ground surface is primarily composed of concrete, asphalt, and rock slabs. These materials are very impermeable, which is very good for supporting transportation and structures; however, this leaves no place for rain water to go but pool up and work it’s way down to the lowest areas. Unless drainage systems are designed and implemented in urban areas, the excess water will continue to accumulate until rain stops long enough for water levels to go down.

In this situation once the water gets to the low area it pools up until there is a new method of dispersal or it drys up.

This is a problem for Santorini since in most cities the shops, restaurants, and homes are located right next to the street with entrances lower, even, or in the best case slightly above the hight of the roads. In a flooding scenario water can easily enter into these places damaging goods, appliances, and furniture which throughout the city can add up to a significant monetary burden.

This is along the road in Fira where an entrance to a building is much lower than the road above it. The black and blue arrows show the direction of water flow. The solid blue highlighted area shows where water would pool up. The dashed white line separates higher ground from lower ground.

Flooding in natural environments is a little bit different as the material the the ground is composed of varies between impermeable, semipermeable, and permeable characteristics. In this case the more permeable materials actually get washed away as the excess water runs over and through the material.

As water naturally flows along the lowest path and permeates through the softer material it actively digs deeper and carries away the material with it.

A good example of flooding due to excessive rain in a natural environment is a trail located just west of Megalochori that winds down along the edge of the island to a rocky shore. The upper part of the trail is almost entirely composed of loose pumice which made for a nice even path a year ago. Unfortunately due to extremely heavy rain during the winter the trail is almost unrecognizable as it was so washed out.

The extreme rutting and loosening of the trail results in a much more treacherous and difficult trail which will limit it’s accessibility to hikers and be much more prone to flooding in the future since a pathway for water already exists. With continued use in poor conditions the trail will become much harder to repair.

The black lines mark the position of the trail in good condition where it would be filled in and smooth. Due to rain water flooding much of the material was washed down trail, making the current conditions very rutted and uneven.

In Arizona my favorite place to be is outdoors and on the trails either mountain biking or hiking. As a result I am interacting with trails multiple times a week and I can see places where the trail has been washed away which makes for a dangerous path or could close down the trial until it is properly repaired. Flooding on trails is not specific to Santorini as this happens all over the world; however, many of the trails on Santorini are built on extremely permeable material that will erode very easily.

Flooding on a trail is one thing, but if a road becomes inaccessible than many people and companies feel the effects. The time and money to fix the road alone are substantial before you factor in the extra time and effort to get past the effected area, or the complete halt of work. This winter Santorini was witness to all of these factors in various parts of the island.

On May 29th, 2019 after torrential rain, the road leading to the Santorini Animal Welfare Association became impassible as it was deeply washed out. The animal sanctuary itself was severely damaged with the rain as huge trenches were formed all around the complex. This was a devastating event which has caused the need to relocate to a new area, but before they can make the move it will be much harder to get necessary supplies brought in for the animals.

Yellow arrow points to location of trail near Megalochori. Green arrow points to the Santorini Animal Welfare Association near Emporio.

While flooding due to rain isn’t as catastrophic as a hurricane or tsunami it is still very much a concern that should be accounted for. On a dry island that normally welcomes rain with open arms, too much can result in massive damage both physically on the terrain itself, and put major strain on the economy as products are ruined and money is spent to repair damages in order to continue normal life.

Even though I see flooding on trails in Arizona, the risks aren’t as high as the trails on Santorini. With the massive tourism year-round there isn’t time to close down the trails to be fixed properly, which leads to treacherous hiking conditions that will only get worse with time.

After observing results of flooding in urban and natural environments and determining why it happened, I am excited to see what can be done to prevent and mitigate flooding in the future that will specifically cater to Santorini’s unique composition and demands.