Storage Capacity Curves

The relationship between elevation and volume of storage is referred to as the storage capacity curve.  It is determined by calculating the volume of water stored for incremental elevations.  In reservoir routing the incremental volume of water between time steps is determined from the input hydrograph, and then from the storage capacity curve a new water surface elevation is determined.

Surveys conducted at the time of a dam construction are used to develop a storage capacity curve as part of the overall design.  This information is generally available for existing, larger dams.  For smaller detention basins geometric shapes (rectangular dimensions) can be used to estimate the storage capacity curve.  Providing digital elevation data are accurate and current they can be used to estimate elevation - volume relationships.