Deriving Wetland Stage-Storage Relationships from GIS Areas

A new approach to define wetland stage-storage relationships using a single shape parameter and a volume-depth (V-h) power-function model is introduced to account for the storage of multiple wetlands in a hydrologic study area. The relationship between the depression area (A), volume (V), and depth of water (h) must often be estimated due to a lack of detailed survey data. Area-depth and volume-depth relations are usually determined from detailed surveys and/or bathymetric maps that are costly and labor intensive to produce, and specific to each depression. The new approach defines wetland stage-storage relationships using a single dimensionless parameter, which defines the shape of the V-h relationship, in conjunction with the maximum wetland pool area and maximum wetland pool depth. Shape parameters were developed using an iterative process for 42 wetlands and subsequently used to generate V-h relationships for each wetland. The study findings are: (1) there is little variability in the dimensionless shape parameter, (2) the mathematical model adequately represents the V-h relations for all wetlands analyzed, and (3) general wetland shape parameters were tested and shown to approximately represent stage-storage relationships for all 42 wetlands in this study. The developed wetland storage equations could be useful in field studies, theoretical investigations and surface/groundwater modeling.