Water management might look different in Marin County as agencies partner to understand extreme weather better. The North Marin Water District, the Marin Municipal Water District and Marin County joined the Center for Western Weather and Water Extremes Water Affiliates Group in January. The group researches “atmospheric rivers” and other severe weather to improve water management, mitigate flood risk and increase water supply reliability. … The National Oceanic and Atmospheric Administration says atmospheric rivers are storms that move most of the water vapor out of the tropics. According to the Water Affiliates Group, heavy rainfall from these flows of condensed water is responsible for almost 85% of floods on the West Coast.