Thrust Areas Ecosystem Water Institute Classification Level
Water, Land Use and Ecosystems Water and Climate Water and Society Water Resources Sustainability Springs Wetlands Watersheds Aquifers Lakes Coastal Zone  Water Institute Classification 1  Water Institute Classification 2  Water Institute Classification 3  Water Institute Classification 4

Analysis of Soil Moisture and Salinity in the Floodplains of the Loxahatchee River Watershed.
Contract No:  64234
Goals and Objectives
Floodplain forests provide unique ecological structure and function, which are often degraded or lost when watershed hydrology is modified. Restoration of impacted ecosystems requires an understanding of surface water, groundwater, and vadose (unsaturated) zone hydrology in the floodplain, however most wetland restoration efforts focus on monitoring and modeling only surface water processes. Soil moisture and porewater salinity are of particular importance for seed germination and seedling survival in systems impacted by saltwater intrusion, but are difficult to monitor! And often overlooked. This study contributes to the understanding of floodplain hydrology in one of the last bald cypress (Taxodium distichum [L.] Rich.) floodplain swamps in southeast Florida (USA) by investigating groundwater, soil moisture, and porewater salinity dynamics in the floodplain of the Loxahatchee River, where reduced freshwater flow has led to saltwater intrusion and a transition to salt-tolerant, mangrove-dominated communities. Twenty-four dielectric probes measuring soil moisture and porewater salinity every 30 minutes were installed along two transects - one in an upstream, freshwater location; the other in a downstream tidal area. Additionally, a network of twelve groundwater wells was developed along five transects that encompass a gradient of floodplain conditions from upstream freshwater areas downstream to the estuary. Data collected over four years quantified the spatial variability and temporal dynamics of groundwater and vadose zone hydrology and showed that soil moisture can be closely predicted based on river stage and topographic elevation (coefficient of efficiency = 0.83). Porewater salinity rarely exceeded tolerance thresholds for bald cypress upstream, but did so in some downstream areas, fully explaining observed vegetation changes for the first time. Dynamic factor analysis (DFA), a multivariate times series analysis technique, proved useful for studying interactions among experimental times series and other hydrological variables in the watershed and helped us develop dynamic factor models (DFMs) of groundwater level, salinity, and soil moisture. The results offer a methodological and analytical framework for floodplain monitoring in locations where restoration success depends on groundwater and vadose zone hydrology and provide relationships for evaluating proposed management scenarios for the Loxahatchee River.
Available Outputs

Title: Calibration of a combined dielectric probe for soil moisture and porewater salinity measurement in organic and mineral coastal wetland soils. Geoderma 161(1-4):50-62.
Authors: Mortl, A., Muñoz-Carpena, R., Kaplan, D. and Y. Li

Title: Complementary Effects of surface water and groundwater on soil moisture dynamics in a degraded coastal floodplain forest. Journal of Hydrol 398(2011):211-234.
Authors: Kaplan, D. and R. Muñoz-Carpena

Title: Growth of bald cypress [Taxodium distichum (L.) Rich.] seedlings in the tidal floodplain of the Loxahatchee River. Biological Sciences 2(74):84-99.
Authors: Liu, G.D., Li, Y.C., Muñoz-Carpena, R., Hedgepeth, M., Wan, Y.S., and R. Roberts

Title: Linking River, Floodplain, and Vadose Zone Hydrology to Improve Restoration of a Coastal River Impacted by Saltwater Intrusion. J. Environ. Qual. 39:1570-1584.
Authors: Kaplan, D., R. Muñoz-Carpena, Y. Wan, M. Hedgepeth, F. Sheng, R. Roberts, R. Rossmanith

Authors: Mortl, Amanda

Title: Untangling complex shallow groundwater dynamics in the floodplain wetlands of a southeastern U.S. coastal river. Water Resources Research 46, W08528.
Authors: Kaplan, D., R. Muñoz-Carpena and A. Ritter, A
Project Lead
Munoz-Carpena, Rafael
Project Participants
Munoz-Carpena, Rafael
Additional Participants
Marion Hedgepeth
David Kaplan
David Kaplan
Yuncong Li
Amanda Mortl
R. Roberts
Rob Rossmanith (FPS)
Yongshan Wan
Fawen Zheng (SFWMD)
Level 1: WI Affiliated Faculty Project
Water, Land Use and Ecosystems
Partner Name(s)
Florida Park Service
Grant Award Dates
1/19/2007 to 12/31/2007