Long‐term hydro‐meteorology and water quality data from low‐gradient catchments of varying scales on the Santee experimental Forest, South Carolina

Abstract

The forest landscape of the Southeastern Atlantic coastal plain of the United States is experiencing increased threats from extreme precipitation events, tropical storms, flooding, droughts, and growing urbanization impacting on vegetation, road infrastructure, water extraction and other related ecosystem processes (e.g., storm runoff, nutrient and carbon cycling) and functions (e.g., flood protection, aquatic habitat). We describe ongoing hydro‐meteorologic monitoring on two first—(1.6 km2 each), the second—(5 km2), and the third—(52.5 km2) order catchments. The catchments are located on the Santee Experimental Forest at the headwaters of the Cooper River that drains into Charleston Harbour, South Carolina. Monitoring started in 1946, with a gap between 1982 and 1989, includes precipitation, weather, streamflow, water table, and water quality (anions, cations, and physical parameters) at varying temporal scales. The catchments are forest ecosystems dominated by loblolly (Pinus taeda) and longleaf pine (Pinus palustris) (LLP) mixed hardwood stands on the uplands and bottomland hardwoods on well‐drained to poorly‐drained soils characteristic of the low‐gradient Atlantic Coastal Plain. These data support multiple field and modelling studies, ranging from water and carbon budgets to hydrologic and biogeochemical processes to effects of microtopography and extreme climate on hydrology and water quality of these coastal catchments withstands regenerated since Hurricane Hugo (1989). One significant finding from the long‐term data was a reversal of the pre‐Hugo flow pattern between the paired watersheds 3 years after Hugo. This reversal persisted for 10 years and was attributed to change in forest vegetation due to hurricane damage to older pine and larger hardwood stands followed by delayed regeneration before full forest recovery. These publicly available data serve as a reference within a rapidly developing landscape and also for addressing potential impacts of extreme climate and forest disturbance on ecohydrology, biogeochemistry, habitat, water supply and infrastructure using validated models and tools.

Hydrometeorological Trends in a Low-Gradient Forested Watershed on the Southeastern Atlantic Coastal Plain in the USA

“…Because the manual rain gauges overflowed during the extreme rain event of 3-4 October 2015, the TC manual/tipping bucket ratio from 28 September 2015 to 2 October 2015 was used to estimate rainfall totals from 2-8 October 2015. After the freezing rain and snow event of 3 January 2018, TC meltwater totals and data from a Pluvio weighing bucket gauge at the distant SEF location [62] were used to estimate precipitation during the 3-8 January 2018 period. Data from each of the automatic rain gauges were verified and calibrated using an adjacent manual rain gauge.…”

“…Data from each of the automatic rain gauges were verified and calibrated using an adjacent manual rain gauge. Breakpoint event rainfall data from the loggers were processed to obtain daily, monthly, and annual totals for each of the three gauges [62,63].…”

“…Flow rates were calculated by the USGS using a stagedischarge relationship. The 15 min flow rates were integrated to obtain the daily, monthly, and annual totals [62,63]. Missing daily data in early 2005 were extrapolated using a calibration relationship with nearby watershed (WS80) [30].…”

“…The second station on a 27 m tall tower also measures air temperature, relative humidity, net radiation, wind speed and direction on a 15 min basis above a forest canopy on nearby WS80 watershed. Details of the stations are provided elsewhere [62][63][64].…”

“…It was measured using water table wells, shallow piezometers (2.5 m depth below ground), and also deeper piezometers (up to 20 m depth) placed into the top of the Gordon Aquifer (Santee Limestone), an important groundwater resource in the region [51]; see Table 2. Time series data for groundwater dynamics at four sites in the watershed were collected on an hourly basis starting in June 2006 on areas representing four major categories of soils (Rains, Goldsboro, Lenoir, and Lynchburg series) in the uplands on the left (south) bank of the watershed and in a fifth well in an area with Wahee soil (on the right bank) starting in January 2011 (Figure 1) [62,63]. Automatically recorded data collection at all sites was discontinued in May 2019.…”