Floods cause many positives and negatives to the surrounding area on which they occur. Flooding is mainly a natural act. It replenishes the land by depositing silt on top of the old soil. By doing this it puts lost nutrients back into the soil. Once the flood has passed and the soil has settled this land is able to be utilised to grow crops on and farm animals. It is a fantastic place for farming. On the other hand floods cause a lot of damage to the surrounding area, washing away anything in its path i.e. houses, trees etc. If cities build on flood plains, flooding can cause billions of dollars damage and loss of lives. Flood plains, are not a great place to start a civilization unless the city is prepared for annual flooding.