Haiti; e-coli; groundwater; springs; satellite imagery; NDVI
Wampler, Peter and Sisson, Andrew, "Evaluation of Spring Flow, Bacterial Contamination, and Distribution of Fresh Water Resources in the Vicinity of Verrettes, Haiti" (2008). Student Summer Scholars Manuscripts. 5.
The purpose of this study was to gain a better understanding of fresh water springs used as the primary source of potable water in rural Haiti. Field data was collected during the summer of 2008 near Verrettes, Haiti, approximately 120 km north of Port au Prince. GPS locations of 29 springs were recorded within the 87 sq km study area. Two water samples at each spring were taken for bacterial analysis: one sample was submitted to a local hospital and a duplicate sample was cultured using Coliscan© Easygel© Kits. Both capped and uncapped springs were sampled to determine whether capping improves water quality. Field water quality parameters and flow volume were recorded at each spring to determine possible correlations with the presence of E-coli and total coliform. Water questionnaires were conducted using Haitian interpreters, regarding household water use, health, and public perception of the water.
A Normalized Difference Vegetation Index (NDVI), created from Landsat 7 imagery, was used to create a predictive map, highlighting areas with NDVI values greater than 0.232 and areas located more than 500 meters from a mapped spring. There is a strong correlation between high NDVI values, spring locations, and outcrops of northwest striking limestone. Spring flow volumes varied from 0.43 to 258.45 L/min. E-coli and total coliform colony counts from the local hospital and Coliscan© Easygel© Kits were very different. However, based on the World Health Organization (WHO) drinking water standard, 71 to 100% of the springs were unsafe to drink. Both capped and uncapped springs had bacterial counts in excess of the WHO standard, suggesting that water treatment from all sources is necessary to ensure clean and safe drinking water. Shallow karst aquifers with open flow paths and high spring temperatures, averaging 26.53° C., may be contributing to observed bacterial abundance.