Warm or cold water for a turtle?

All lizards are cold blooded so they don't have techniques to stay cool besides hiding in the shade, under something, or in a hole to hide from direct heat. They need the warmth given by the sun to live. This is why they brumate during the winter. They need heat to digest food and in the winter they eat much less for this purpose. So just avoided the sun to keep cool and basking and laying on warm surfaces to keep warm.