Date of Award

2017

Document Type

Open Access Dissertation

Department

Art

Sub-Department

Geological Sciences

First Advisor

Claudia Benitez-Nelson

Abstract

Stormwater detention ponds are widely utilized as control structures to manage runoff waters during storm events. These sediments also represent significant sites of organic carbon and nutrient burial. Here, carbon (C) and nutrient sources and burial rates were determined in 14 residential stormwater detention ponds throughout coastal counties of South Carolina. Bulk sediment accumulation was directly correlated with catchment impervious surface coverage (R2 = 0.90) with sediment accumulation rates ranging from 0.06 to 0.50 cm y-1. These rates of sediment accumulation and subsequent pond volume loss are lower than expected indicating that required maintenance dredging schedules be reassessed. Strong, positive correlations between the Terrestrial Aquatic Ratio (TARHC) biomarker index and sediment accumulation rate (R2 = 0.77), in conjunction with high C:N ratios (16 – 33), suggests that terrestrial biomass drives this sediment accumulation, with relatively minimal contributions from algal derived material. Carbon and nutrient concentrations are consistent between ponds and differences in burial rates were therefore driven by rates of bulk sediment accumulation. Rates of C and nutrient burial (C: 8.7 – 161 g m-2 y-1, N: 0.65 – 6.4 g m-2 y-1, P: 0.238 – 4.13 g m-2 y-1) are similar to those observed in natural lake systems, but lower than those observed in reservoirs or impoundments. Though individual ponds are small in area (930 – 41,000 m2), they are regionally abundant and potentially capable of sequestering C and nutrients at environmentally significant rates.

Rights

© 2017, William Schroer

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