SPATIAL VARIATION OF DAILY RAINFALL AND NETWORK DESIGN

A high-density pilot network of 10 rain gauges was implemented in the Everglades Nutrient Removal (ENR) Project to quantify areal rainfall o ver the site for accurate computation of wafer budget. The ENR Project , located in south Florida, is a 1500 ha wetland that was constructed to reduce phosphorus loads in agricultural runoff from the Everglades Agricultural Area (EAA) that enters the Water Conservation Areas (WCAs ). The first 158 days of wet season daily rainfall data were used to e valuate the adequacy (or redundancy) of the network. A spatial correla tion function was developed to characterize the spatial variation of w et season rainfall over the site. An exponential spatial correlation m odel was fitted to the data with an R(2) value of 0.74. A method that compares relative error to rain gauge density was applied to determine the required minimum gauge density. It was determined that a five rai n gauge network with uniform distribution was the most efficient desig n.