Most waterfall enthusiasts are not looking for dry scientific data and complex indicators. For them, it is more important to understand characteristics that are easy to digest.
Bulgaria is a small mountainous country with thousands of short rivers and small associated watersheds. As a result, the seasonality of water flow is highly pronounced. Over the past 30 years, we have observed prolonged periods of drought. Even waterfalls traditionally considered to be perennial now experience periods of minimal surface flow, and the trend toward partial or total drying during the summer months is intensifying. An additional impact comes from the numerous water catchments along mountain rivers, which alter the natural flow regime and, consequently, the characteristics of the waterfalls.
Based on the conditions described above, we have selected a classification consisting of three types of waterfall status:
• Perennial
– the waterfall flows throughout the entire year, although the volume of water may vary significantly depending on the season.
• Seasonal
– the waterfall flows only during certain times of the year, most commonly during the colder half of the year, during the spring snowmelt or after periods of heavy and prolonged rainfall.
• Ephemeral
– the waterfall flows only for a few days immediately following heavy rain or rapid snowmelt, after which it dries up completely.
