Various regions of Thailand are prone to seasonal flash-flooding due to their tropical savanna climate. The floods often occur in the north and spread down the Chao Phraya River through the central plains, in the northeast along the Chi and Mun Rivers flowing into the Mekong, or in the coastal hillsides of the east and south. Remnants of tropical storms that strike Vietnam or the peninsular south commonly increase precipitation, resulting in further risk of flooding. Drainage control systems, including several dams, irrigation canals and flood detention basins, have been constructed,[8] but are inadequate to prevent flood damage, especially in rural areas. Much effort, including a system of drainage tunnels begun in 2001,[9] has been put into preventing the inundation of the capital city, which lies near the mouth of the Chao Phraya and is prone to flooding, with considerable success. Bangkok has seen only brief and minor flooding since the major flood of 1995. Other regions, however, had experienced severe flooding as recently as 2010.