Due to the limited battery capacity of sensor nodes, a minimization of energy consumption is a potential research area in underwater wireless sensor networks (UWSNs). However, energy hole and coverage hole creations lead performance degradation of UWSNs in terms of network lifetime and throughput. In this paper, we address the energy hole creation issue in depth-based routing techniques, and devise a technique to overcome the deficiencies in existing techniques. Besides addressing the energy hole issue, the proposition of a coverage hole repair technique is also part of this paper. In areas of the dense deployment, sensing ranges of nodes redundantly overlap. Our proposed technique takes a benefit of redundant overlapping and repairs a coverage hole during network operation. Simulation results show that our two techniques cohesively conserve nodes' energy, which ultimately maximizes the network lifetime and throughput at the cost of increased delay.