1. A method of determining underground water content, comprising: receiving a first scan of an area at a first polarization, the first scan including first L band microwave reflections of the area; receiving a second scan of the area at a second polarization, the second scan including second L band microwave reflections from the area, the first and second scans being from a first sensor for detecting L band microwave radiation reflections, the sensor being attached to an object located at least 50 meters above the area; filtering electromagnetic noise from the first scan using the second scan; creating a water roughness map based on typical roughness values of a set of types of water sources and the filtered first scan; identifying a first type of water source using the water roughness map and the filtered first scan; and calculating the water content at locations in the area based on the identified first type of water sources.