Lake Chad is an endorheic lake located along the international borders of four countries - Niger, Nigeria, Cameroon, and Chad. Over the past four decades, Lake Chad has shrunk from about 25,000 sq km in the 1960s to only ~3,000 sq km in the 2000s. As the severe drying pattern of the Lake has been observed through comparisons of satellite images since the 1960s, many studies have been conducted to find potential causes of the shrinkage. However, due to difficulties of accessing the site, these studies were mostly based on remotely-sensed data and computational modeling. In 2008 and 2009 we performed an extensive field survey along the Komadugu Yobe River in the southwest of Chad Basin toward the Lake. During the field expedition, we observed important changes that are hardly detected from the remotely sensed data such as: increase of groundwater near the Lake, land conversion with loss of vegetation, increase of wetland and farming area around the Lake, and even increase of rainfall near the Lake. The present talk will show what observation we can have from the ground, what challenge we can expect in the collection of ground-truth data, and how we can fill the gap of understanding the fate ofLake Chad with remotely-sensed data.