Flood control was also a concern for cities located in flood prone areas. These areas were especially susceptible to flood and storm damage. Rainfall resulted in several rivers reaching major flood stage. As a result, surface runoff can quickly flood streams and rivers. In the early days, the river would frequently flood. Gates are raised and lowered depending on water levels in the reservoir and flood conditions. Remission was given to peasants when the harvest failed during times of flood or drought. It occurs in freshwater rivers and streams, which generally flood seasonally. Heavy rainfall is characteristic of Bangladesh causing it to flood every year. Some of the lakes present a danger of a glacial lake outburst flood. Threat management involves a wide variety of threats including physical threats like flood and fire. The dam succeeded in significantly reducing the damage done by the 1969 flood. The dam is expected to minimize the effect of even a "super" flood. Johnstown is home to the Flood City Water Polo team. They can also flood various ecosystems on land and may cause extinctions.