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Watercourses and riparian areas

Riparian areas are the wooded strips along watercourses and constitute specific ecosystems at the interface between terrestrial and aquatic environments.

Guadeloupe watercourses

Guadeloupe has a dense hydrographic network: 55 perennial watercourses, 4 canals, more than 350 gullies, 3,000 waterholes and a dozen ponds!

The vegetation along watercourses, or riparian area, enjoys remarkable biodiversity, and is home to more than 1,700 native species of trees, shrubs and herbaceous plants that play an essential role in maintaining the banks.

Learn more about Guadeloupe's aquatic environments >

The proper functioning of a watercourse depends in part on the good ecological condition of its riparian area. Unfortunately, Guadeloupe watercourses and their low-lying riparian areas are sometimes in an alarming state of degradation. Many species are threatened with extinction, for various reasons.

Invasive alien species

Under the pressure of numerous anthropic factors, watercourses and more particularly their riparian areas are affected by the massive invasion of alien species . During phase 1 of the project PROTEGER , 75% of Basse-Terre inventoried riverbanks are home to invasive alien species.

Some species, classified as invasive, threaten the balance of aquatic and riparian ecosystems.

Learn more about endangered flora in Guadeloupe >Learn more about endangered flora Overseas >

Break in ecological continuity

The functionality of some watercourses may be degraded due to structures across watercourses or along the banks.

These structures have harmful effects on the ecological continuity of ecosystems: bank artificialization modifies sediment transport, reduces riparian areas’ filtering functions , hinders the movement of migratory species, etc.

Pollution and water quality

Many watercourses are polluted by chemical substances, including pesticides - especially chlordecone and glyphosate. Fragmentation of riparian ecosystems and destruction or degradation of riparian areas along watercourses facilitate the transfer of chemical substances, passing directly from agricultural plots into the heart of watercourses. In addition, large amounts of waste worsen the situation: household waste, tires, domestic pollution, etc., clearly hampering the reconstitution of riparian areas and the good state of water environments.

More about water quality in Guadeloupe >

12 types of Guadeloupe's riparian areas

Phase 1 of the project " PROTEGER " has improved knowledge of the structure and functioning of ecosystems bordering watercourses.

Sections of watercourses
below 125 m in altitude

Type 1

Mangrove

Altitude: <5 m
Width of the watercourse (bottom width): Variable
Gradient: No or low gradient (0 to 1%)
Current:  Usually slow
Salinity: (>1g/L)

See document

Type 2

Watercourse in flood zone

Swamp forest or cleared flood zone
Altitude: <50 m (ici 1-28 m)
Width of the watercourse (bottom width): <10 m
Gradient: Low : 1% (0-6%)
Current:  Usually slow
Salinity: (<1 g>

See document

Type 4

Open watercourse

Wide watercourses with unconnected riparian areas and low to medium gradient
Altitude: <100 m (2-72 m)
Width of the watercourse (bottom width): >20 m
Gradient: Low to medium: 1.5% (0-3%)
Current:  Usually low to medium
Salinity: <1 g>

See document

Type 5

Semi-open watercourse

Fairly wide with partly connected riparian areas and medium gradient
Altitude: <100 m (ici : 50-100 m)
Width of the watercourse (bottom width): 10-20 m
Gradient: Average : 3.3% (1-11%)
Current:  Usually medium to fast
Salinity: <1 g>

See document

Type 6

Closed watercourse with medium gradient

Narrow, fully connected riparian areas
Altitude: <100 m (ici : 32-120 m)
Width of the watercourse (bottom width): <5 m
Gradient: Average: 4.9% (1-17%)
Current:  Usually low to medium
Salinity: <1 g>

See document

Type 7

Closed watercourse with a steep gradient

Narrow, fully connected riparian areas; gully type
Altitude: <100 m (ici : 10-116 m)
Width of the watercourse (bottom width): <10 m
Gradient: Steep: 7.9% (1-20%)
Current:  Usually fast (but very sporadic)
Salinity: <1 g>

See document

High altitude watercourse sections between
125m and 300m of altitude

Type 8

Open watercourse with medium gradient

Wide, with partially connected or unconnected riparian areas
Altitude: 125-300 m (ici : 230-235 m)
Width of the watercourse (bottom width): >20 m
Gradient: Average: 4% (1-8%)
Current:  Usually fast
Salinity: <1 g>

See document

Type 10

Closed watercourse with a steep gradient

Narrow, fully connected riparian areas; gully type
Altitude: 125-300 m (ici 116-245 m)
Width of the watercourse (bottom width): <10 m
Gradient: Steep: 15% (8-21%)
Current:  Very variable
Salinity: <1 g>

See document

Watercourse sections between 
altitude 300 m to 500 m

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