Hydrologic Signature Analysis of Select Organic Hydric Soil Indicators in Northeastern Florida

Abstract

The magnitude, duration, and return intervals of surface water flooding and dewatering of the landward extent of the hydric soil indicators muck (LM), histic epipedon (LHE), and Histosol (LH) were quantitatively defined, providing a better understanding of the hydrologic conditions maintaining these hydric soil indicators. Land surface elevations were determined for the LM, LHE, and LH at 16 lakes with long‐term (30–60‐yr) modeled or gauged hydrologic data. The probability of flooding and dewatering of the elevations of the LM, LHE, and LH were determined from frequency analysis of hydrologic data from each lake. The resulting hydrologic signatures for the LM, LHE, and LH are composed of magnitude and return interval of 1, 30, 90, 183, 274, and 365‐d duration flooding and dewatering events. As an example, the LM, LHE, and LH were flooded for 30 continuous days with average annual probabilities of 42, 65, and 77%, respectively. As a second example, the LM, LHE, and LH were dewatered for 365 continuous days with average annual probabilities of 49, 24, and 16%, respectively. Probabilities of flooding and dewatering for the LM, LHE, and LH are presented for 1, 30, 90, 183, 274, and 365‐d durations. Mean hydrologic signatures reduce variability and may be considered representative of each soil characteristic. Quantitatively defining the hydrology associated with the presence of the LM, LHE, and LH as well as other soil characteristics is essential for environmental protection, assessment of hydrologic impacts, wetlands restoration, wetlands creation, and other environmental management applications.