With an area at low tide of about 30 hectares, it is a low-lying area and mangrove forest, belonging to the development reserve mangrove land plan. Around Pearl Island, it is shielded by perennial tiger, parrot, and mangrove trees with wide canopy woven together like a wall to prevent waves. Inside, an earthen embankment about 500m long separates the sea water and the natural drainage system, and also serves as a walking path. Thanks to this embankment, the water level in the tank is always kept stable.