What is the fine-grained topic of the following text: In 2006, slightly more than 3,000 acre-feet of water -- nearly a billion gallons -- were released from Cedar Bluff, slowly creeping downstream along the Smoky Hill River to Pfeifer, where the city of Russell has its main wells. Only return the topic.
Water release from Cedar Bluff to Russell City via Smoky Hill River in 2006