Caspian Sea water level is dropping

Marine infrastructure at risk

Not every country is struggling with rising sea levels. Instead, the countries around the Caspian Sea are experiencing a falling water level. Over the past decade, the water level has dropped by some 10 to 20 cm a year. This causes all kinds of complications in the shallow northern part of the Caspian Sea for keeping the current marine infrastructure, such as ports and navigation channels, accessible. An issue that is difficult to tackle as a locally active engineering firm.

For instance, the dropping sea level affects the way forces act on quay structures, especially when the sea floor is lowered to ensure boats can still reach the quay. We recently mapped the safety at certain water levels and future sea bottom levels of some of the quays.

Based on this, we have devised short, medium and long-term measures for a cost-effective extension of the lifespan of quays and thus delaying major investments for as long as possible. After all, there is always a chance that the water will rise again, as it has done before.

In reality, the Caspian Sea is not a Sea, but the world’s largest lake. It is not connected to any sea either. The water balance depends on the water supplied by rivers (Volga and Urals) and, additionally, the water that evaporates or is extracted. Throughout the centuries, the water level has always fluctuated. Many examples of this can still be found ‘in the field’. For example, along the beach, where the retreating water exposes ancient foundations, or in Baku, the capital of Azerbaijan, where the Qız Qalası ‘maiden tower’ is located on the edge of the old city, far from the current coastline. It used to be located in the water, to defend the city from attacks from the sea.

It is unclear exactly what causes these large fluctuations. The most obvious causes are a change in precipitation in the catchment area of the feeder rivers, or a different evaporation rate due to higher temperatures. There are even exotic explanations, such as movements of tectonic plates causing a changing volume of the Caspian Sea basin. However, no one has yet been able to find an explanation based on historical data as to what causes it, let alone predict how the situation will be in the coming years.