Estimation of infiltration rates of saturated soils at selected sites in the Caloosahatchee River basin, southwestern Florida

Soil infiltration measurements were made at 23 sites in the Caloosahatchee River Basin in Glades, Hendry, and Lee Counties in southwestern Florida. The sandy soils of the basin are characterized by high infiltration rates limited in some areas by a high water table during the wet season. Because soil characteristics are similar within the basin, soils are classified by landscape group based on landscape cover and associated drainage. In accordance with this designation by the South Florida Water Management District, 11 sites are classified in the rock landscape group, 7 in the flatwoods landscape group, 4 in the slough landscape group, and 1 in the depression landscape group. Data for 16 sites were fit to Horton's equation by using a regression analysis to estimate the infiltration rates of saturated soils. For some sites, an outlier value was removed prior to the regression analysis. Seven of the sites did not yield data that fit Horton's equation. The flatness of the plotted data suggests that saturated conditions may have been reached early in the test. The infiltration rate of saturated soils for these sites was estimated by averaging the data collected after the first 20 minutes of the test. For all sites, the estimated infiltration rates of saturated soils ranged from 9.8 to 115 centimeters per hour in flatwoods, 3.4 to 66 centimeters per hour in rock, and 2.5 to 55 centimeters per hour in slough. The estimated soil infiltration rate at the one site in the depression was 181 centimeters per hour. Five sites were located on irrigation control berms where infiltration rates of the highly compacted and rocky soil may not represent the rates of less disturbed soils at sites within the same landscape groups.