Impacts of 40 Years of Land Cover Change on Water Quality in Tampa Bay, Florida

Land cover changes in the Tampa Bay watershed (Florida) over the past four decades were examined along with precipitation and wind observations to help understand causes of long-term changes in turbidity and chlorophyll concentration within the Tampa Bay estuary. Water quality showed a statistically significant relationship to land cover fraction in the watershed compared to long-term precipitation or wind stress. Redundancy Analyses with Akaike’s Information Criterion and non-parametric multiple regressions determined that turbidity and chlorophyll concentration decreased bay-wide from 1974–2012 with increased developed land fraction (R2 > 0.75, p-value < 0.05). Various segments of the estuary showed different significant responses to developed land (R2 > 0.75, p-value < 0.05), agricultural land (R2 > 0.93, p-value < 0.02), bare land (R2 = 0.77, p-value = 0.001), and wind stress (R2 = 0.91, p-value = 0.04) at different times of year.