The Four Dragons
Once a great drought had spread across the land. Four dragons from the sea noticed the plight of the people and traveled to beseech The Jade Emperor in the Heavenly Palace to bring the rains to the people. He was very busy ruling the heavens, earth, and sea and distractedly agreed to the send the rains on the next day if they would return to the sea, but soon after the dragons departed, he forgot his promise.
After ten days, the rains still did not come and the people began to die of starvation. The dragons could not simply stand by and do nothing, and so they decided to use their bodies to capture great masses of water from the sea, taking it upon themselves to bring the rain. The people were grateful and prayed their thanks to the Jade Emperor, who soon discovered what the dragons had done, and became angry that they intervened without his blessing.
The Jade Emperor ordered Mountain God to trap the four dragons. However, from each mountain that trapped a dragon there sprung a new river. From Yellow Dragon came the Yellow River, from Long Dragon the Yangtze River, from Black Dragon the Amur River, and from Pearl Dragon the Pearl River. The rivers thereafter flowed from west to east and north to south, the dragons ensuring that the peoples of China would never be without water again.