From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Namu's Village (ナム の 村, Namu no Mura; FUNimation "Nam's Village") is a desert village and the home of Namu.
Water was very scarce and there were many droughts in the area of Namu's Village. Namu entered the Tenkaichi Tournament to gain money to buy water for his village. He lost in the tournament to Son Goku, however, but Turtle Hermit gave him a Capsule to store water for free to save the village.
The water was quickly used up and Goku helped Namu get more. It was found out that the lack of water was being caused by Giran's race blocking the river with a dam made of Merry-Go-Round Gum. This was later destroyed when Goku blasted the dam with the Kamehameha.
Dragon Ball Z