**2. Water resources planning and conservation**

Currently, we are concerned about the potential water scarcity in the face of increasing, primarily population-driven, water demands and its impact on energy and food production and food security [5]. In addition, the combined pressures of population growth and climate change significantly increased water demand [6]. Therefore,

water resource planning and conservation are critically important globally. The effective planning and conservation of water resources provide water resource security, which is important for agricultural, municipal, and industrial water demands.

Water resource planning and conservation are strongly connected because both processes complement each other. For example, the best and most effective planning is needed to conserve water resources. The best management practices in any watershed, whether agricultural, urban, or forested watersheds, help conserve water resources. For example, if farmers practice climate-smart farming for an agricultural watershed, they can conserve water resources and increase food production.

This section includes three highly diverse chapters focusing directly and indirectly on water resources planning and conservation. For example, while one chapter focused on approaches to improve water productivity, the other discussed the multiscale perspective for the conservation planning of riverine fishes. Further, this section focused on multiscale environmental relationships, which are important for water resource conservation and river basin planning. This section also discussed potential approaches to improve migration routes for aquatic animals, which are critical for biodiversity and the ecosystem.
