Water Quality and Sediment Sources in the Bluefields River, Westmoreland, Jamaica

Bluefields Bay is located along the southwest coast of Jamaica and is threatened by poor water quality in runoff released from coastal communities and inland watershed areas. This study will determine water quality trends and polluting sediment sources of the Bluefields River and evaluate its influence on bay and coral reef conditions. Two approaches will be used: (i) short-term water quality monitoring program at multiple sites in the 5 km2 watershed; and (ii) sediment fingerprinting using similarities in soil and sediment geochemistry to match potential sediment source to active stream loads. This study supports the thesis research of two MSU graduate students and involves the PI and students in working with local environmental groups in Jamaica. Scientific contributions include being the first study to scientifically address water quality problems in Bluefields Bay and improving our understanding of the linkages between upland soil erosion and coastal sedimentation.

The specific objectives of the project are:

  1. Determine the concentrations and spatial patterns of nutrients and bacteria transport by implementation of short-term water quality monitoring program at multiple locations in the Bluefields River system;
  2. Use sediment fingerprinting techniques on soils/sediment deposits (potential sources) and active channel sediments and near-shore bay muds (current transport trends) to determine the source of excess sediment loads to the bay;
  3. Use geospatial data analysis and mapping technologies to classify land use and sediment sources within the watershed and quantify their relative influence on water quality and sediment delivery in the watershed (i.e. create a source map based on scientific results); and
  4. Produce two environmental educational posters for the BPCA that display “results summary and applications” of the research project.

A watershed monitoring approach is used to evaluate concentrations, identify sources, and quantify transport patterns of three contaminants that are recognized generally as causes of pollution in the area: nutrients (total phosphorus and nitrogen), bacteria (Ecoli, coliform), and sediment (fine-grained, suspended). Both nutrient and bacteria assessments involve water sampling along the Bluefields River and statistical evaluations of concentration measurements. Sediment sampling and analysis will be based on a sediment source finger-printing approach that compares the geochemical composition the different source materials in the watershed (e.g. upland soils, slope deposits, floodplain sediments) to similar characteristics in the active channel and bay sediments. The most important source materials for sediment inputs in the watershed will be those most closely related to the composition of present-day sediment loads to the bay.