Deltares: Spotlight on Guayaquil Flood Issues
Guayaquil, a city situated on the Guayas River and the most important port in Ecuador, has often suffered flooding due to its location and urban growth.
With a tidal range of 3.5 meters and severe squalls, water management of the city is one of the authorities’ biggest worries.
Sedimentation in the Guayas River is considered the culprit. It leads to higher water levels and hinders the drainage of water and the passage of ships.
As a result, an island has formed in the middle of the river. Increasing numbers of birds on the so-called Islote del Palmar form a danger for the nearby airport.
It also causes the river banks of the Samborondón neighborhood to erode faster.
Originally, people in Guayaquil assumed that deforestation upstream was the primary cause of the increased sedimentation.
Before implementing effective measures, it was decided to carry out a broader analysis first using the new program Delft3D Flexible Mesh from Deltares. It revealed that the cause of the increased sedimentation did not lie upstream, but rather downstream in the estuary.
This was confirmed when primarily sea sand rather than river sand was dredged up.
The presence of sea sand in the river can be explained by the asymmetry of the tide, amplified by earlier land reclamation, and by upstream dams reducing the washing-out of the river. The upstream deforestation did have some effect as well.
In calm waters, silt and clay (fine material) was found.
The authorities now want to determine what measures to take using the Delft3D Flexible Mesh.
Deltares staff are giving a training course for this purpose in Guayaquil. This is done in collaboration with the Spanish consultant Intecsa-Inarsa.
The total project is commissioned by EMAPAG (Guayaquil water company) and CAF (financier).
The problems and possible solutions for Guayaquil were also discussed during the Habitat III conference in Quito, Ecuador, during a public session in the Netherlands pavilion.