According to the pilot, he made a go-around after his first approach due to the aircraft traffic in the area. In diverting his attention to monitoring the traffic, he forgot to switch the fuel tank selection. As the airplane turned onto the crosswind leg of the traffic pattern, the engine began to sputter and subsequently experienced a total loss of power. The pilot switched to the other fuel tank in an attempted to restart the engine, but was unsuccessful. With the airplane's altitude decreasing, he decided to ditch in a lake to avoid a housing area. A postaccident inspection by a Federal Aviation Administration inspector revealed that the airplane incurred substantial damage to the left wing and fuselage; they found no evidence of preimpact mechanical anomalies. The pilot opined that the engine had a loss of power due to fuel starvation.