AWA completed Probable Maximum Precipitation, Precipitation Frequency, and Climate change Assessments for the mining operations in central Bulgaria These outputs were utilized for all aspects of hydrologic analyses, water management activities, and engineering design decisions related to mining operations.
| Basin (10 km2) | 24-hour | |||
| ARI | AEP | 50% | 5% | 95% |
| 1 | 9.9-1 | 21.8 | 20.5 | 24.3 |
| 2 | 5.0-1 | 53.5 | 51.1 | 55.2 |
| 5 | 2.0-1 | 76.4 | 73.5 | 79.0 |
| 10 | 1.0-1 | 93.6 | 90.2 | 97.3 |
| 25 | 4.0-2 | 117.8 | 112.9 | 124.6 |
| 50 | 2.0-2 | 137.8 | 130.8 | 148.4 |
| 100 | 1.0-2 | 159.4 | 149.9 | 175.0 |
| 200 | 5.0-3 | 183.1 | 170.2 | 205.6 |
| 500 | 2.0-3 | 217.6 | 198.2 | 252.6 |
| 1,000 | 1.0-3 | 246.6 | 221.4 | 293.5 |
| 5,000 | 2.0-4 | 324.7 | 280.8 | 410.7 |
| 10,000 | 1.0-4 | 363.7 | 310.8 | 472.8 |
| 100,000 | 1.0-5 | 521.0 | 423.3 | 747.0 |
| 1,000,000 | 1.0-6 | 732.6 | 561.1 | 1169.6 |
| 10,000,000 | 1.0-7 | 1017.2 | 737.4 | 1811.9 |
| 100,000,000 | 1.0-8 | 1399.7 | 959.0 | 2794.3 |
| 1,000,000,000 | 1.0-9 | 1914.1 | 1232.4 | 4314.3 |
| 10,000,000,000 | 1.0-10 | 2605.8 | 1573.7 | 6628.3 |
