Data visualization, time-series analysis, and mass-balance modeling of hydrologic and water-quality data for the McTier Creek watershed, South Carolina, 2007-2009

Abstract

The McTier Creek watershed is located in the headwaters of the Edisto River Basin, which is in the Coastal Plain region of South Carolina. The Edisto ecosystem has some of the highest recorded fish-tissue mercury concentrations in the United States. In an effort to advance the understanding of the fate and transport of mercury in stream ecosystems, the U.S. Geological Survey, as part of its National Water-Quality Assessment Program, initiated a field investigation of mercury in the McTier Creek watershed in 2006. The initial efforts of the investigation included the collection of extensive hydrologic and water-quality field data, along with the development of several hydrologic and water-quality models. This series of measured and modeled data forms the primary source of information for this investigation to assess the fate and transport of mercury within the McTier Creek watershed. The visualization of data is an important tool for understanding the trends and influencing variables of an ecosystem. One of the initial efforts for evaluating the hydrology and water quality in the McTier Creek watershed was the development of a digital spreadsheet for systematically visualizing and interrogating selected hydrologic, water-quality, and model data. This report briefly describes the development and application of the McTier Creek Data Viewer. The extensive database incorporated into the data viewer also provides a means for analysis and the development of analytical tools that may provide insights into the water quality within the McTier Creek watershed. One such application was the development of a simple water-quality load model that utilized a massbalance equation in conjunction with the topography-based hydrological model (TOPMODEL) developed to simulate flow in the McTier Creek watershed. Several variations of this simple load model were developed and are presented in the report.

Characterizing mercury concentrations and fluxes in a Coastal Plain watershed: Insights from dynamic modeling and data

“…Therefore, we developed a mass balance algorithm and applied it to the surface and subsurface flow components simulated by TOPMODEL, resulting in a load model that assesses the daily mass fluxes for a given constituent (Hg T ). Details of the TOPLOAD model are also available elsewhere [ Benedict et al , 2011]. In this investigation, we apply the TOPLOAD‐H variation of our TOPMODEL load model, which utilizes simulated surface and subsurface flow components from TOPMODEL and assigns each flow component a Hg T concentration.…”

HydroQual: Visual analysis of river water quality

“…Some approaches are enriched with statistics and charts (e.g. see [9,10] or ArcGIS Geostatistical Analyst 1 ). Techniques based on more sophisticated plots [27,33] or self-organizing maps [38] have also been studied.…”

Climate change and watershed mercury export: a multiple projection and model analysis

“…The TOPLOAD‐Hg (herein referred to as TOPLOAD) model is an empirical load model that quantifies the daily mass‐loading rates for a given constituent (in the present study, THg) at an assessment point within the stream and identifies flow components from which THg loads originate using the hydrological structure from the TOPography based hydrology MODEL (TOPMODEL) a physically based, semidistributed watershed model that simulates the hydrological fluxes (i.e., runoff) from the landscape to the stream . The TOPMODEL was previously calibrated and validated in the McTier Creek Watershed , and each flow component was assigned a uniform THg concentration (5 ng L −1 THg) . This assigned value reflects the average THg concentration under a variety of flow conditions (i.e., low, high, and base flow), insights from field measurements between 13 June 2007 and 30 September 2009, and studies by Hornberger et al and Robson et al that provide suggestions on how to assign these values.…”