Hydrological and Geomorphological Controls on the Water Balance Components of a Mangrove Forest During the Dry Season in the Pacific Coast of Nicaragua

Hydrological and geomorphological processes are key to mangrove forest growth and development. However, few mangrove hydrology studies exist in Central America. A 0.2 km2 mangrove forest on the Pacific coast of Nicaragua was investigated to determine the water balance dynamics during the dry season. The used multi-methods approach combined hydrology, hydrochemistry and geophysics. Precipitation is the main freshwater input. Beach ridges are the key geomorphologic features which allowed an increase in water storage of 351 m3d−1 during a 22 day period. Large precipitation events cause breaking of the beach ridges by excess water, suddenly emptying the system. Grey water and pit latrines from the nearby town influence shallow groundwater quality, but also provide extra nutrients for the mangrove forest. Groundwater chemistry is also affected by calcite dissolution and seawater. Refreshening and salinization processes are controlled by the general groundwater flow direction. Hydraulic and hydrochemical influence of seawater on coastal piezometers seems to be controlled by the elevation of the water table and the tidal amplitude. These conditions control forest subsistence during the dry season, which is essential for the mangrove forest to provide ecological and economic benefits such as protection against flooding, habitat for numerous species, and tourist attraction.