PS 5-63 - Correlation of hydrological wells established at Biscayne National Park soil elevation table monitoring sites and stage gauge managed by the south Florida water management district report

Monday, August 7, 2017
Exhibit Hall, Oregon Convention Center
Ana Rojas1,2, Kevin Whelan3 and Andrea Atkinson3, (1)Florida International University, Miami, FL, (2)Student Conservation Association, (3)South Florida/Caribbean Network of the National Park Service, Palmetto Bay, FL

The South Florida/Caribbean Network (SFCN) is one of 32 Inventory and Monitoring networks within the National Park Service, specifically monitoring the state of natural resources (vital signs) in 7 parks located throughout South Florida and the U.S. Virgin Islands. An important vital sign within this network is the change of the coastal geomorphology in both regions. The purpose is to monitor long term trends in soil surface elevation relative to sea level rise. This sub-project focused on understanding the hydrology of the soil elevation table (SET) sites specifically the duration that each site is exposed to water. This in turn can explain the shrink-and-swell (contraction and expansion of the soil horizon), productivity, and decomposition that affect the overall soil elevation. The SFCN had established rudimentary wells with Ultra Sensus pressure sensors at both of the SET sites in Biscayne National Park (BISC). This project report describes an alternative using a nearby, permanently installed and maintained hydrology data box that records the water stage for Biscayne Bay and correlating it to the hydrological patterns of the BISC soil monitoring sites. Our overall approach was to first calculate on-site water depths based upon site pressure transducers, determine if there was a relationship between the BISC 1 Site water depth readings and the BBCW8 hydrology stage gauge (managed by the South Florida Water Management District) water depth data, determine if it was possible to relate water depth at BBCW8 to periods when the BISC 1 Site was flooded in order to estimate the relative amount of time in a 6 month period a site was flooded, determine if a relationship exists between maximum water depth at the BBCW8 and BISC, and finally take the steps and repeat them for BISC 2 Site.


While not providing a complete picture of the hydrology, at this point we are able to predict the duration of flooding (average hours per year of flooding presence is 1,439), and hydroperiod of the BISC sites using the BBCW8 stage data and that there is a strong correlation with a linear regression r2 values of .80-.95 between the maximum depths of each data set within 12 hr periods. These findings can potentially allow us to eliminate the wells at the BISC sites and only use the BBCW8 stage gauge to predict the hydrology at the sites with occasional use of sensors in wells to re-validate the relationship once every 3-5 years.