The Ghar el Melh lagoon and its territory covers 30 km². It is a 2800 years old city, with a very rich history. There are no major fresh water inputs, and the high water salinity is maintained by permanent exchanges with the sea. About 10500 inhabitants live around the lagoon, mainly from agriculture and fishing. Beaches receive the highest number of tourists in Tunisia per year. This project focuses on Nature Based Solutions dedicated for two issues to achieve the sustainability of the Ghar el Melh ecosystem: (1) increasing local natural biodegradation capacity of soils to trap polluted waters delivered by urban sewage systems; and (2) re-development of dunes ecosystems by fixing them with natural barriers in order to protect the coast line, to enhance the biodiversity and to save waters . The demosites are part of the OMELI observatory, under implementation by the INSTM (Observatory of the Ghar el Melh Littoral, National Institute of Marine Sciences and Technologies).
Fresh water: Ecosystems play a vital role in the global hydrological cycle, as they regulate the flow and purification of water. Vegetation and forests influence the quantity of water available locally.
Erosion prevention and maintenance of soil fertility: Soil erosion is a key factor in the process of land degradation and desertification. Vegetation cover provides a vital regulating service by preventing soil erosion. Soil fertility is essential for plant growth and agriculture and well functioning ecosystems supply the soil with nutrients required to support plant growth.
PPT(mm/yr): 582.0
T(ºc): 18.5
Elevation of demosite: | 1.0 meters above sea level |
Humidity: | Humid |
PETr (by year): | 0.92 |
As there are no significant surface water inputs to the GML, hydrological processes are mainly driven by the links between the sea and the lagoon waters, while little is known about the possible influence of groundwater in the nearby agricultural area to the West and Southwest, which are very flat areas (former Medjerda alluvial plain). The main source of pollution is the city of Ghar el Melh and few waste water small channels to the West, while agriculture activities bring some diffuse pollution along the northern and western shores of the lagoon.
* Quantification of the hydrological processes at lagoon and watersheds scale, mapping the risk impacts and territorial solutions * Identification of potential areas for enhancement of ecosystem sustainability (dunes, waste waters and soil/water productivity) * Managing biota to control hydrological and biogeochemical processes (ecological engineering)
Two dedicated solutions : (1) Pilot site for domestic waste water natural cleaning through constructed planted biofilters, with soil biodiversity enhancement, and REUSE for sustainable soil and water productivity (vegetable agriculture and fisheries). (2) Set-up of dune-fences on the sandy lagoon barrier to restore natural ecosystem services of the sand dunes, to stabilize and restore the foreshore, and the coastal aquifer and mitigate the sea level rise impact on coastal areas and human l.
Social ecohydrological system
EH Objectives
EH Methodology
Catchment Ecohydrological sub-system
Objectives
Stakeholders
Catchment Sociological sub-system
Activities