Legacy sediment stored in sinkholes: a case study of three urban watersheds in Tennessee, United States of America

Abstract

As closed topographic depressions, sinkholes effectively divide karst regions into a series of subwatersheds, where swallets within each sinkhole define the downstream end of each subwatershed. Water and sediment are temporarily stored in sinkholes before continuing to underground streams. While pathways and travel times of water in karst terrain are commonly found using tracing techniques, such techniques do not provide information about the movement and travel time of sediment through these systems. This paper reviews the literature regarding sediment storage within sinkholes and presents a case study, the objective of which is to estimate the magnitude and timing of sediment deposition within three sinkholes in an urbanized area in Tennessee, United States of America. Sedimentation rates in sinkholes were estimated based on age determination of cultural artifacts (buried trash and coal fragments) and by 14 C dating. For the three study sinkholes, minimum deposition rates (maximum residence times) were 15 cm yr −1 (6 yrs), 1.5 cm yr −1 (81 yrs), and 0.2 cm yr −1 (640 yrs). The analysis revealed that sinkholes undergo fill and flush cycles at different timescales caused by changes in upland sediment supply and morphologic changes at swallet openings. Sinkholes that lack swallet openings, or with swallets that have become blocked by debris, are effectively disconnected from master streams with regard to sediment. Sediment stored in sinkholes may be released downstream when swallet conditions change.

Evaluating susceptibility of karst dolines (sinkholes) for collapse in Sango, Tennessee, USA

“…Flooding occurs when rain input is greater than the drainage capacity of the doline swallets, and the doline volume parameter identifies the amount of water that can be captured and stored by a doline when its swallet either does not exist (solution dolines) or drainage by the swallet is not sufficient often due to increasing amount of sediment input. The increase of sediments in dolines is a result of urbanization and residential development because urbanization causes changes in the vegetation, soil erosion and sediment transport; this has been documented in other parts of the Tennessee karst (Hart, 2014). …”

Paleoflood records from sinkholes using an example from the Ebro River floodplain, northeastern Spain

“…Sinkholes are enclosed depressions characteristic of karst regions that may result from the differential corrosional lowering of soluble bedrock (solution sinkholes) or from subsurface dissolution and the subsidence of the overlying sediments (subsidence sinkholes) by different mechanisms (i.e., collapse, sagging, and suffosion) (Gutiérrez, 2016 and references therein). Sinkhole sediments have been investigated for multiple purposes: (1) reconstructing paleoenvironmental and paleoclimatic variability (e.g., Laury, 1980; Whitmore et al, 1996; Hyatt and Gilbert, 2004; Morellón et al, 2009; Barreiro-Lostres et al, 2014); (2) investigating paleontological and archaeological sites (e.g., Carbonell et al, 2008; Calvo et al, 2013; Zaidner et al, 2014; Gutiérrez et al, 2016); (3) estimating erosion rates and their temporal variability in small catchments (e.g., Turnage et al, 1997; Hart, 2014); (4) inferring quantitatively the evolution of the subsidence phenomena using the trenching technique in combination with geochronological data (e.g., Gutiérrez et al, 2009, 2011, 2014; Carbonel et al, 2014, 2015; Gutiérrez, 2016); and (5) identifying the sedimentary signature of hurricanes recorded in bedrock collapse sinkholes, both onshore (cenotes) and offshore (blue holes) (Gischler et al, 2008; Lane et al, 2011; Brown et al, 2014). For example, Brown et al (2014) recognized two historical hurricanes (1967 Hurricane Beulah and 1991 Hurricane Gilbert) in the sediments of an 80-m-deep sinkhole lake located 10 km inland of the Caribbean coast on the Yucatan Peninsula, Mexico.…”