Total renewable water resources in Ghana 2020, by source

The release date is the date of access.

The source notes that External Renewable Water Resources (ERWR) is that part of the country's long-term average annual renewable water resources that are not generated in the country. This includes inflows from upstream countries (groundwater and surface water), and part of the water of border lakes and/or rivers.
The source further explains that ERWR consider the quantity of flow reserved by upstream (incoming flow) and/or downstream (outflow) countries through formal or informal agreements or treaties. This signifies that, it may vary with time, and in extreme cases, it may be negative when the flow reserved to downstream countries is more than the incoming flow.

Internal Renewable Water Resources (IRWR) is the long-term average annual flow of rivers and recharge of aquifers generated from endogenous precipitation. The source notes that the double counting of surface water and groundwater resources is avoided by deducting the overlap from the sum of the surface water and groundwater resources.