There are many (1) factors that cause floods in Vietnam, including natural factors and human factors. Rainfall, the influence of tides, storms, and tropical depressions (2) are natural factors. Because Vietnam has "An average annual rainfall of (3) between 1,500 to 2,000 mm", heavy (4) rain often causes floods in cities which have poor drainage systems. In Vietnam, (5) especially in the Central area, each flood is a nightmare for residents. According to a student in Phu Hoa city (Phu Yen province), "Flood occurs on the rainy (6) season from October to November every year (7) because of heavy rain or Ba Ha's hydropower plant discharges the (8) water."