Water plays a critical role in supporting life and ecosystems. However, a combination of ever-growing demands on water resources and low water use efficiency has caused severe water and environmental stresses, increasing the risk of contamination. An interdisciplinary, integrated and balanced approach is required to secure the safety of the water supply and water environmental management systems.

The development of a sustainable, multifaceted and multilevel water cycle system is a new and fast-growing focus in the field of water. The water cycle has traditionally referred to the natural circulation system, where water evaporates, condenses and falls to the ground in a continuous cycle. However, attention is shifting to the water meta-cycle, where water has multiple interactions with the environment, ecology, hydrology, hydraulics, civil engineering, meteorology and topography under different scales and dimensions. Understanding this water meta-cycle, the processes involved, and their potential impact is a scientific challenge of enormous importance. Progress is needed to advance our knowledge and to inform sustainable development.

Water Cycle is an interdisciplinary open access journal that publishes top-tier original research in all areas of water cycles, including meta-cycles. It examines their relationship to science, technology, society, economics, health, culture, policy, regulation and strategy. It also offers water academics, engineers and practitioners the opportunity to exchange knowledge and experience.

Papers will report significant advances in a wide range of categories including (but not limited to):

• The different dimensions of water cycles: natural cycle, social cycle, ecological cycle, engineering cycle, cascading cycle and process cycle.
• The different scales of water cycles: water meta-cycle, local cycle, regional cycle, watershed cycle and environmental cycle.
• Water conservation in agricultural, industrial, domestic and municipal applications.
• Water treatment, recycle and reuse for different water resources, including wastewater, industrial wastewater, drinking water, reclaimed water, rainwater, seawater, mine water and brackish water.
• The water cycle-environment-ecosystem nexus.
• The water-waste-soil-atmosphere nexus.
• How water cycles interlink and interact with elements, materials and energy flows.
• Water mediated material transformation, element cycle and energy flow.
• The interactions, synergies and coordination between water conservation, reuse and the water cycle.
• Water system analysis, water policy and water management.