Surveys will be conducted to establish elevations in the areas representative of the water level recorders. Additional surveying will be conducted to identify the steepest gradients in the marsh. Leveling will entail use of either an optical or laser surveyor's level, a stadia rod and reflecting prism, and accessory equipment. Groundwater wells that have not already been surveyed will be leveled. Data will be analyzed to determine, at minimum, the sources of water responsible for rises in water table, and at what distance along the continuum tidal dominance yields to atmospheric control of water table fluctuations.