ASSESSING THE IMPACT OF WEATHER AND ANTHROPOGENIC FACTORS ON WATER QUALITY IN THE HOPE RIVER, JAMAICA (Invited Presentation)

The Hope River, Jamaica was classified in 2000 as being in a state of deterioration due to increased concentration of faecal coliforms and nitrates over the previous decade. Subsequently, additional data were collected up to 2014. These historical data on water quality from the Hope River watershed were obtained from the local environmental regulatory agency for: Total Suspended Solids (TSS), Total Dissolved Solids (TDS), pH, Nitrates, Ortho-phosphates, Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) and were subjected to statistical analyses. Meteorological data were also acquired and assessed. Analysis of these data revealed that the weather pattern within the study area has cycled twice within the study period with a rainy period from 2000-2007 and a dry period from 2008-2014, and air temperatures within the study area have increased by 1.6% since 2008-2014. Water quality parameters assessed within the Hope River respond to rainfall with several significant statistical correlations.

A Water Quality Index was determined for each year of the study period using the parameters found in the local ambient water quality monitoring standard. The index was generally higher in the 2001-2007 rainy period with an increasing trend towards 2007; it remained constant for the dry period 2008-2014 and was also generally lower than the previous period assessed. These findings suggest that the weather pattern, potentially influenced by climate change, is the major impactor of water quality in the Hope River and not anthropogenic activities as previously concluded. During the rainy period, rainfall can be used as a good predictor of surface water quality in the Hope River and in the period of lower rainfall, water quality measured using the Water Quality Index seems to be greatly affected by pH.

Parametric and non-parametric tests reveal that pH, BOD, Nitrates, TDS and TSS correlate very strongly with rainfall. TDS and BOD were negatively correlated while the others were positively correlated with rainfall. Only nitrates and TDS showed significant correlations with land use on a scale basis. Nitrate was positively correlated and TDS was negatively correlated with the urbanization of the Hope River watershed.