What do LDC and HDC mean?

What is LDC (Lowest Daily Clearance)?

LDC represents the minimum water safety level, also known as Lowest Daily Clearance. This is a critical threshold below which navigation on the Danube becomes dangerous or impossible for certain types of vessels. If the water level drops below LDC, there is a risk of grounding, collisions with underwater obstacles, or major navigational difficulties.

What is HDC (Highest Daily Clearance)?

HDC represents the maximum water safety level, known as Highest Daily Clearance. When the water level exceeds this threshold, there is a risk of flooding, loss of vessel control, or damage to infrastructure (dikes, banks, etc.). HDC is an important indicator for navigation safety and flood protection.

Why are LDC and HDC important?

The LDC and HDC levels are critical for safe navigation on the Danube and for the safety of riverside regions. Constant monitoring of these values helps prevent accidents and economic or environmental damage. Alert systems, such as the Danube Alert app, are essential to inform users when water levels approach these critical limits.

How dangerous are these levels?

Both dropping below LDC and rising above HDC can cause serious problems:

• LDC dangers: Navigation becomes hazardous, with risks of grounding or accidents where vessels may hit the riverbed or other underwater obstacles. Additionally, maritime transport may be halted, leading to significant economic losses.
• HDC dangers: The risk of flooding is very high. The water flow may become too strong, affecting vessel stability and causing damage to riverside infrastructure. In some cases, even homes and farms in low-lying areas may be affected by uncontrolled water level rises.