the wet season is correlated with weaker trade winds off the ocean. The pH level of water becomes more balanced due to the charging of local aquifers during the wet season. Water also softens, as the concentration of dissolved materials reduces during the rainy season. Erosion is also increased during rainy periods. Arroyos that are dry at other times of the year fill with runoff, in some cases with water as deep as . Leaching of soils during periods of heavy rainfall depletes nutrients. The higher runoff from land masses affects nearby ocean areas, which are more stratified, or less mixed, due to stronger surface currents forced by the heavy rainfall runoff. Floods High rainfall can cause widespread flooding, which can lead to landslides and mudflows in mountainous areas. Such floods cause rivers to burst their banks and submerge homes. The Ghaggar-Hakra River, which only flows during India's monsoon season, can flood and severely damage local crops. Floods can be exacerbated by fires that occurred during the previous dry season, which cause soils which are sandy or composed of loam to become hydrophobic, or water repellent. In various ways governments may help people deal with wet season floods. Flood plain mapping identifies which areas are more prone to flooding. Instructions on controlling erosion through outreach are also provided by telephone or the internet. Life adaptations Humans The wet season is the main period of vegetation growth within the Savanna climate regime. However, this also means that wet season is a time for food shortages before crops reach their full maturity. This causes seasonal weight changes for people in developing countries, with a drop occurring during the wet season until the time of the first harvest, when weights rebound. Malaria incidence increases during periods of high temperature and heavy rainfall. Nonhuman animals Cows calve, or give birth, at the beginning of the wet season. The onset of the rainy season signals the departure of the monarch butterfly from Mexico. Tropical species of butterflies show larger dot markings on their wings to fend off possible predators and are more active during the wet season than the dry season. Within the tropics and warmer areas of the subtropics, decreased salinity of near shore wetlands due to the rains causes an increase in crocodile nesting. Other species, such as the arroyo toad, spawn within the couple of months after the seasonal rains. Armadillos and