Water and sediment analysis in the pilot site of Pripris de Yiyi in French Guiana


The Pripris de Yiyi site extends over 2,471 acres, and presents a variety of environments: bodies of water with aquatic plants, wet grassland, savannas, forests with sand barriers, coves. This site is recognized as being of international importance (Ramsar site). Acquired by the Conservatoire du littoral in 1996, it was co-managed by the town of Sinnamary and SEPANGUY (environmental protection association).

The Pripris de Yiyi

The Mang program aims to define a future management plan (2016-2021), namely by providing new data on the hydrological function and environmental quality of the body of water.
Impact Mer represents a group of companies (Impact Mer, Hydreco, Bios), and was selected to complete this study.  The first assignment was conducted in French Guiana from December 3 to 10, 2014.

A launch meeting was organized on December 4, uniting a number of environmental stakeholders (institutions, associations, users). This made it possible to define the methodology behind the elaboration of the management plan, and to suitably adapt the protocol for assessing the area’s environmental quality.

Monitoring stations were installed, as decided by expert stakeholders in the field of water and those proficient in site hydrology. Their location was chosen (i) to identify and characterize water input and output, (ii) to assess the impact of users and human development, and (iii) to get an overall idea of the environmental quality.

Monitoring and measurements carried out within the framework of the MANG program
prpris 3
Field measurments

In-field visits were organized (discovering the site, observing how the weed-cutter works, observing the fauna and flora), and an initial sampling campaign was completed. Ten monitoring stations were installed, from which a team made up of Impact Mer and Hydreco workers characterized the site’s currentology and conducted water and sediment analyses. Each station was positioned and characterized (type of environment, flow, depth, substrate). In each station, a Doppler-like current meter was used to measure the speed and direction of the flows at varying depths of the water column. Physico-chemical parameters were measured on-site (dissolved oxygen, pH, temperature, salt levels). This data will help map water circulation in the marshes and thus assess the areas with high or low renewal rates. Water and sediment samples were taken for further laboratory analysis, with a view to determining the presence and concentration of over 180 substances (mercury, other metals, phytosanitary and industrial products, hydrocarbons, micro-pollutants). These analyses are conducted 4 times a year, to assess the contamination variations in the environment according to the season. The marshes’ hydrodynamics and corresponding data on environmental quality was then used to create links with other environmental management concerns such as the presence of certain plant or animal species.

Meetings with the site’s major stakeholders were also held. These made it possible to collect data on the site’s history, and on the various visions and purposes of the site as seen by each stakeholder.


Félix Bompy, research officer – Impact Mer