Wireless underground sensor networks (WUSNs) are networks of wireless sensor nodes operating below the ground surface, which are envisioned to provide real time monitoring capabilities in the challenging underground environments comprising soil and water medium. Despite the potential advantages, the realization of WUSN is a very complex task. The main challenge in this area is the realization of efficient and reliable underground links to establish multi-hop underground communication and efficiently disseminate data for seamless operation. However, the hostile underground environments do not allow the direct usage of most, if not all, existing wireless communication and networking solutions, mainly because of the extremely high path loss, small communication range, and high dynamics of the electromagnetic (EM) waves when penetrating the soil, sand, water etc. medium. In this paper the possibilities and limitations of using wireless sensor networks that can effectively operate underwater are investigated. The objective of the paper is to address the unique and important issues related to the transmission in of wireless sensor networks in an underground environment especially in the water. In particular, the underwater communication channel is modeled considering not only the propagation of EM waves in water, but also other effects such as multipath, water type, and water depth. The propagation characteristics are investigated through simulation. Moreover, based on the proposed channel model, the resulting bit error rate is analyzed. The theoretical analysis and the simulation results prove the feasibility of wireless communication in the 300-700 MHz band in underwater environment and highlight several important aspects in this field.