On the Understanding of the Hydrodynamics and the Causes of Saltwater Intrusion on Lagoon Tidal Springs

Abstract

Springs are common features on the Yucatán coast. They can discharge either under the sea (submarine) or inland in coastal lagoons and wetlands. Previous observations of a coastal lagoon located on the northern Yucatán Peninsula (La Carbonera) reported sea water intrusion on a spring that discharge on a coastal lagoon (lagoon tidal spring). The saltwater intrusion occurs when the tide is at its lower level, which is the opposite to what has been reported for submarine springs in the Yucatán Peninsula. In this study, the hydrodynamics of the spring is analyzed and the driving forces controlling the seawater intrusion are identified and discussed. Time series of water levels, salinity, and velocity measurements in the lagoon, the aquifer, and the spring are analyzed by means of tide component decomposition and cross-correlations analysis of the tide signals. Results show that the main driving forces causing the intrusion are the density differences and pressure head gradients, and the mechanisms influencing the driving forces driving those differences are the tides, the friction in the lagoon, and the confinement of the aquifer; other mechanisms are discussed to present a complete idea of the complexity of the interactions between the coastal aquifer, the coastal lagoons, and the sea.

Changes in the Rhizosphere Prokaryotic Community Structure of Halodule wrightii Monospecific Stands Associated to Submarine Groundwater Discharges in a Karstic Costal Area

“…In this region SGD distribute in the area mixing seawater and groundwater, thus producing estuarine conditions in the sea [ 32 ]. X’Buya-Ha spring is located approximately 350 m from the coastline ( Figure 1 b) and is the most energetic discharge of the Yucatán coast, with water flow velocities up to 2 m s −1 depending on the tide, nutrient inputs and reductions in background salinity (36) to values ranging from 21 to 23 [ 30 , 33 , 34 ]. Despite other seagrass species develop in the area, only H. wrightii monospecific stands can be found near X’Buya-Ha spring with S. filiforme and T. testudinum dominance increasing with distance from the spring [ 30 ].…”

Characterization of the Morphological Behavior of a Sand Spit Using UAVs

“…The northern coast of Yucatan is a barrier island with a length of approximately 350 km. Freshwater is discharged to the coast via the confined aquifer groundwater in the form of submarine springs [29], as well as springs in coastal lagoons and wetlands [30]. The port of Sisal, located on the northwestern side of the Yucatan Peninsula (Figure 1b), was built with two jetties in 1987 [31] to maintain a ~66 m wide waterway (Figure 1c).…”