Prediction of sea level rise (SLR) in response to climate change has been the focus of worldwide research, most focusing on the impact by human development. The research has been limited to estuaries and tidal rivers near harbors dealing with the hydrodynamics of reversing tidal flows. This article focuses on the Waccamaw River National Wildlife Refuge in coastal South Carolina where freshwater unidirectional flow is common. We examined the record of water levels in the Waccamaw and Pee Dee Rivers over the period 2007–2019 and the length of record of the United States Geographical Survey (USGS) gauge at Pawleys Island on the Waccamaw River. The Atlantic Ocean, off the southeastern coast of the US, has experienced accelerated SLR since 2000. National Oceanic and Atmosphere Administration (NOAA) tide gauges from Fort Pulaski on Cockspur Island in Georgia to Beaufort, North Carolina, show significant increase in long-term SLR since then with an average since 2007 of approximately 10 mm y-1. Since the study period was less than the 18.6-year cycle of lunar precession, tidal ranges were expanding for much of the study period resulting in the rate of rise of Mean Higher High Water (MHHW; the average of the highest tide levels during each day) being greater than the rate of increase of Mean Lower Low Water (MLLW; the average of the lowest tide levels during each day) in all ocean stations. We examined water levels at NOAA and USGS gauges from Oyster Creek, in North Inlet to Conway on the Waccamaw River and Near Bucksport on the Pee Dee River. We found mean water levels increased more rapidly with distance from the ocean with an apparent SLR > 40 mm y-1 at Conway on the Waccamaw and Bucksport on the Pee Dee. In contrast to the ocean NOAA gauges, the estuary/river gauges showed more rapid increase of daily minimum water level (an approximation of MLLW) than daily maximum water level (an approximation of MHHW) with an extreme of apparent rise of minimum water levels of 58 mm y-1 at Bucksport on the Pee Dee. Nearly 50% of the increase in apparent SLR was due to an increase in the annual average freshwater flow of the Pee Dee and Waccamaw Rivers. Over the past 13 years the Waccamaw National Wildlife Refuge has experienced an apparent SLR that was more than double that observed at the edge of the ocean. The rise has been greater in the height of daily low water than in the height of daily high water. The increase was driven by both tidal hydrodynamics and an increase in the rate of flow in the Pee Dee and Waccamaw Rivers. These findings have important implications for land managers, policymakers, and homeowners in the region as people in the middle to upper estuaries need to plan for rates of relative SLR rise much greater than the frequently discussed rates in the ocean.

In 1989, Hurricane Hugo inflicted catastrophic damage on approximately 1.8 million ha of forested land in South Carolina. The purpose of this study was to monitor species compositional shifts and structural changes in several forest types following the hurricane's disturbance. The immediate consequences of hurricane damage are well documented, but there are few studies based on the long-term compositional and structural changes that may result from hurricane disturbance, especially in temperate forest ecosystems. Forty-two forested plots were monitored within four study areas that received varying degrees of hurricane damage. Inventories included species, damage class, tree diameter, and regeneration. The objectives of this study were (1) to compare the recovery speed of wetland forests (e.g., bottomland hardwood swamps and cypress-tupelo swamps) to that of upland pine and hardwood forests; (2) to discover how the degree of hurricane damage can affect the timing and the pattern of forest recovery in the coastal plain; and (3) to compare individual species response patterns across different forest types and at different levels of initial damage. Over the 27-year period following the hurricane, successional pathways have been variable among plots of different forest types and intensity of initial disturbance. We have observed an expected increase in basal area (BA) following the disturbance. Sapling populations in many species have increased dramatically, and some of these populations have begun to thin in recent years. In several forest types, loblolly pine (Pinus taeda L.-not a predominant species in these sites prior to the hurricane) responded quickly and overtook some dominant species in BA and tree/sapling abundance. Several other species that were not a major component of the tree strata (wax myrtle [Morella cerifera (L.) Small], green ash [Fraxinus pennsylvanica Marsh.], and the invasive Chinese tallow [Triadica sebifera (L.) Small]) showed a large increase in sapling population. Overall, recovery speed and species resilience were specific to forest types and damage severity. The intensity and frequency of hurricanes may increase in the future as sea surface temperatures rise. Understanding how coastal forests respond to major hurricanes in the short-term and the long-term will aid us in preparing for future hurricanes and for potential changes in disturbance regimes.

In this study, we calibrated and tested the Soil Conservation Service Curve Number (SCS-CN) based Modified Sahu-Mishra-Eldo (MSME) model for predicting storm event direct runoff (Q(tot)) and its soil saturation coefficient alpha as a threshold antecedent moisture condition for partitioning into overland surface and shallow subsurface runoff components. The model calibration was performed using 36 storm events from 2008 to 2015 on a 160-ha low-gradient forested watershed (WS80) on poorly drained soil. The model was further validated without cali-bration using data from 2011 to 2015 on two sites [115 ha (Conifer) and 210 ha (Eccles Church)] and from 2008 to 2011 on a third site, the 100-ha Upper Debidue Creek (UDC), all similar forested watersheds on the Atlantic Coastal Plain, USA. The calibrated MSME model was able to accurately predict the estimated Q(tot_pred) for the WS80 watershed, with calculated Nash-Sutcliffe efficiency coefficient (NSE), RMSE-standard deviation ratio (RSR), and percent bias (PBIAS) of 0.80, 0.44, and 16.7%, respectively. By applying the same calibrated alpha value of 0.639 from the WS80 to two other similar poorly drained watersheds, the MSME model satisfactorily predicted the estimated Q(tot_pred) for both the Eccles Church (NSE = 0.64; RSR = 0.57; PBIAS = 28.9%) and Conifer (NSE = 0.60; RSR = 0.58; PBIAS = 21.3%) watersheds, respectively. The MSME model, however, yielded un-satisfactory results (NSE =-0.13, RSR = 2.06, PBIAS = 616.3%) on the UDC watershed with coarse-textured soils, indicating the possible association of the alpha coefficient with soil subsurface texture. Based on the analysis of event rainfall and pre-event water table elevation, and linking them with the calibrated alpha coefficient that describes the proportion of saturated depth in a soil profile, it was found that rainfall was the main determining factor for overland runoff generation. These results demonstrate the MSME model's potential to predict direct runoff in poorly drained forested watersheds, which serve as a reference for urbanizing coastal landscapes in a changing climate.

Undeveloped forested wetlands in the valleys of coastal plain rivers can play a large role in storing floodwater and attenuating river flooding. In the lower Pee Dee, Little Pee Dee, and Lynches Rivers, these wetlands played a large role in mitigating downstream flooding following Hurricane Florence. Wetland forest flood mitigation was most effective for large flows in the Great Pee Dee River, where flooding on former river terraces determined the course of overbank flow and the potential storage of floodwaters. Floodwater storage and attenuation of water level were less effective if larger flows were limited to the Little Pee Dee River. Large rains prior to Hurricane Matthew, and to a lesser extent Tropical Storm Bertha, caused the forested wetland to be a source of additional flow, although with little increase in peak stage.

Over past years, extreme tropical storm events along the North and South Carolina coasts—and subsequent river flooding—have warranted the need for a better understanding of the hydrologic response to these events to protect life, property, businesses, and natural and cultural resources. Our focus in this study is the Pee Dee and Waccamaw River systems, which ultimately flow into Winyah Bay near Georgetown, South Carolina. River flows, coupled with the tidal nature of these freshwater systems, are complex and difficult to predict. The objective of the work is to analyze publicly available data from gauging stations along those river system as measured during Hurricanes Matthew and Florence and Tropical Storm Bertha—three uniquely different storm systems that produced varying rainfall depth, duration, and intensity across the Pee Dee Basin. The most important factor in tidal river analysis is the location of the stagnation point , where downstream river flow exactly balances upstream tidal flow. River flow only controls water level upstream of a tidal stagnation point, while ocean tide controls the water level downstream of a tidal stagnation point. An analysis of major flooding following Hurricanes Matthew, Florence, and Tropical Storm Bertha was used to determine the river flows associated with tidal stagnation at each stream gauge active during these storms. A major limitation of the analysis was a lack of flow data for the tidal channels in Georgetown County, which resulted in uncertainty in the flow associated with stagnation and uncertainty in the role played by each of the creeks that connect the Pee Dee and Waccamaw Rivers. Ignorance of the roles of these creeks most limited understanding of the relative importance of Pee Dee and Waccamaw flow to cause stagnation near Pawleys Island and Hagley gauges on the Waccamaw River and the Socastee gauge on the Atlantic Intracoastal Waterway.

Sustainable management of forested wetlands requires an understanding of water Table (WT) dynamics affected by rainfall and evapotranspiration (ET) and management practices, designed to sustain water quality, quantity, and ecosystem functions and productivity. In this paper analysis of long-term data from four drained and six undrained sites on coastal forested wetlands showed that their growing season WT dynamics depends upon ET as affected by vegetation stand age, with undrained sites yielding deeper WT than the drained young sites but shallower than the mature ones. Wetland hydrology criterion was not met on any of the drained sites including with controlled drainage and one unditched site with moderately well-drained sandy soil, where the WT was within 30 cm of the surface for <8% of the time compared to 31% or greater on undrained sites. WT response was similar on both drained and undrained watersheds soon after vegetation removal compared to the baseline level. Similarly, the WT dynamics on all soil types and vegetation behaved similarly during extreme storms. No trend was found in limited annual mean WT data. These results may have implications for coastal wetland forest restoration and modeling studies relating wetland hydrology as affected by anthropogenic and natural disturbances.

This paper examines data from 18 USGS gauges in the lower Pee Dee Basin in an effort to explain the behavior of the flooding following Hurricane Florence (2018) in Georgetown County, South Carolina. Despite record or near-record flooding in all the tributaries to the Winyah Bay estuary, water levels near the city of Georgetown were well below predicted heights. Floodplain storage in the lower Great Pee Dee, Lynches, and Little Pee Dee River valleys stored over 1.2 million acre-feet of floodwaters, delaying peak stage near Bucksport for five days and reducing peak flow into the Winyah Bay tidal river/estuary system by nearly 50%. An unknown amount of flow from the Winyah Bay tidal river/estuary system flowed through the Atlantic Intracoastal Water Way to Little River rather than through Winyah Bay. The resulting freshwater flow to Winyah Bay only moved the point of tidal stagnation (where upstream tidal flow balances downstream freshwater flow) to near Georgetown. Since the city of Georgetown was near the point of stagnation, water level there was driven by ocean tidal height rather than river flood stage. The lack of discharge data from the tidal rivers in Georgetown County prevents evaluation of the importance of each of these factors and will limit efforts to make quantitative predictions of future flooding in the county.

Tidally influenced coastal forested wetlands can be divided into two broad categories, mangroves and freshwater forested wetlands. These forested wetlands perform valuable ecosystem services, and both are endangered by threats of sea level rise and land use. Understanding the mechanisms that control the distribution of tidal forests has been greatly enhanced by innovation in measurement and modeling of tidal forcing brought about by satellite observation of sea level. Oceanographic hydrodynamic models can now be merged with riverine hydraulic models to address forcing functions in the upper estuary and tidal river. There are new opportunities to study these unique forested ecosystems in a context of (a) the physical driving mechanisms that control their distribution and (b) the anthropogenic and natural disturbances that impact these ecosystems. Remote sensing and geographic information system technology and hydrodynamic, hydraulic, and hydrologic modeling can and must be combined to understand the functioning of these dynamic systems and their interactions with the environment. This chapter summarizes the tidal process and ecosystem characteristics of tidal forested wetlands, with examples from eastern China and the Southeastern United States. The first example demonstrates the need for hydrodynamic modeling to correctly interpret a time series of satellite images in order to evaluate the impact of human management on tidal wetlands. The second examines both empirical data on tidal dynamics and geospatial modeling to examine effects of sea level rise on freshwater forested wetlands. A short review of two widely used large-scale hydrologic models is also provided for describing the flow transport in intertidal rivers, a transition between tidal estuaries and freshwater nontidal wetlands.

This article compares the short-term and long-term hydrology of two typical forests in the humid Atlantic Coastal Plain, including a relatively undisturbed forest with natural drainage in South Carolina (SC) and a drained pine plantation in North Carolina (NC), using monitoring and modeling approaches. Highly dynamic outflow (O) from both of these systems is driven by the water table (WT) position, as influenced by rainfall (R) and evapotranspiration (ET). The annual runoff coefficient (ROC) varied from 5% in dry years to 56% in wet years, depending on the soil water storage (SWS), with a significantly higher average value for the NC site despite its deeper WT, on average, than the SC site. Although both sites behaved similarly in extreme climate conditions, the change in SWS above the WT influenced the annual RO, ROC, and ET. The 17-year average annual ET of 1114 mm (R - O, assuming annual balanced SWS) for the SC site was significantly higher (p = 0.014) than the ET of the drained NC site (997 mm) despite the SC site's lower mean annual R of 1370 mm, compared to 1520 mm for the NC site. This may be due to both the higher potential ET (PET) and soil water-holding capacity of the SC site. The SC site had higher frequency and duration of WT near the surface during winter, deeper summer WT, and higher correlation of annual ET to annual R (r(2) = 0.90 vs. 0.15), suggesting that the SC site was often moisture-limited, particularly during the growing season. Most of the streamflow in these systems occurred during winter, with low ET demands. However, summer periods with tropical storms also resulted in large RO events, generally with higher frequency and longer durations at the drained NC site. These results are similar to an earlier short-term comparison with an unstable behavior period at the SC site after Hurricane Hugo (1989). This study highlighted (1) the differences in hydrology between coastal forests drained for silvicultural production and undrained natural forests managed only for restoration, (2) the importance of long-term monitoring and the effects of regeneration as well as vegetation management on flow regime, and (3) the application and limitations of two widely used models (MIKESHE and DRAINMOD) in describing the hydrology of these forests. Long-term studies can be a basis for testing new hypotheses on water yield, stormwater management, wetland hydrology, vegetation restoration, bioenergy production, and climate change, in addition to applications of proper models for assessing the eco-hydrologic impacts of land use and climate change on freshwater coastal forests linked with downstream riparian rivers and estuaries affected by tidal fluxes and sea level rise.

This article compares the short-term and long-term hydrology of two typical forests in the humid Atlantic Coastal Plain, including a relatively undisturbed forest with natural drainage in South Carolina (SC) and a drained pine plantation in North Carolina (NC), using monitoring and modeling approaches. Highly dynamic outflow (O) from both of these systems is driven by the water table (WT) position, as influenced by rainfall (R) and evapotranspiration (ET). The annual runoff coefficient (ROC) varied from 5% in dry years to 56% in wet years, depending on the soil water storage (SWS), with a significantly higher average value for the NC site despite its deeper WT, on average, than the SC site. Although both sites behaved similarly in extreme climate conditions, the change in SWS above the WT influenced the annual RO, ROC, and ET. The 17-year average annual ET of 1114 mm (R – O, assuming annual balanced SWS) for the SC site was significantly higher (p = 0.014) than the ET of the drained NC site (997 mm) despite the SC site’s lower mean annual R of 1370 mm, compared to 1520 mm for the NC site. This may be due to both the higher potential ET (PET) and soil waterholding capacity of the SC site. The SC site had higher frequency and duration of WT near the surface during winter, deeper summer WT, and higher correlation of annual ET to annual R (r2 = 0.90 vs. 0.15), suggesting that the SC site was often moisture-limited, particularly during the growing season. Most of the streamflow in these systems occurred during winter, with low ET demands. However, summer periods with tropical storms also resulted in large RO events, generally with higher frequency and longer durations at the drained NC site. These results are similar to an earlier short-term comparison with an unstable behavior period at the SC site after Hurricane Hugo (1989). This study highlighted (1) the differences in hydrology between coastal forests drained for silvicultural production and undrained natural forests managed only for restoration, (2) the importance of long-term monitoring and the effects of regeneration as well as vegetation management on flow regime, and (3) the application and limitations of two widely used models (MIKESHE and DRAINMOD) in describing the hydrology of these forests. Long-term studies can be a basis for testing new hypotheses on water yield, stormwater management, wetland hydrology, vegetation restoration, bioenergy production, and climate change, in addition to applications of proper models for assessing the eco-hydrologic impacts of land use and climate change on freshwater coastal forests linked with downstream riparian rivers and estuaries affected by tidal fluxes and sea level rise.

Large floodplain forests, such as the area preserved by Congaree National Park in South Carolina, are among the most dynamic terrestrial ecosystems known on earth. Flooding and migration of river meanders constantly disturb, create, and erode forest habitats. This provides abundant opportunities for new primary succession. Like many long-term processes, meander evolution is primarily understood from extrapolation of short-term measurements (events or 1-2 year campaigns), decadal-scale rates from comparison of mid- to late 20th century aerial photographs, or millennial-scale trends from geological and geomorphic analysis. There is often a gap in detailed analysis of century -scale geomorphic trends without excessive and expensive radiometric dating techniques. A unique opportunity to examine more than 100 years of channel change on the Congaree River is presented by an 1885 map. This 1:6,000 scale map was prepared from a survey conducted by the US Army to determine the cost of removing snags and rocks impeding steamboat traffic. Using modern GIS techniques maps from that survey were scanned from the National Archives, georeferenced to a modern datum, and used to create a shapefile of the riverbank position in 1885. This project demonstrated problems substantially different from similar efforts georeferencing antique maps, primarily caused by the linear feature and landform changes associated with an alluvial river. A LiDAR based DEM was critical to achieving reasonable river positions and the RMS error was 23 m (75 ft) compared to average bank migration of 155 m (500 ft) over the 114 -year period.

This chapter examines the hydrology of forested areas that are subject to soil saturation by precipitation, groundwater or surface flooding. They include mangroves and other tidal forests, the forested portions of peatlands and tree-dominated wetlands defined by the Ramsar Convention. They also include estuarine tidal forests, palustrine forested wetlands and the portions of palustrine scrub-shrub which are made up of immature tree species of the Cowardin et al. classification. A broad outline of the ecology of all wetlands is described, wetlands specifically with tidal influence are described, while descriptions of northern and southern forested wetlands can be found in previous publications.

This chapter provides the future directions in forest hydrology. Challenges include changes in forests and water yield associated with climate change, land-use change, resistance of the public to forest modification, and the ever-present effects associated with disturbances such as fires, the age distribution of forests, insects and diseases, and forest regeneration impacts besides the natural ones. As the world demands more clean water supply, wood, energy and carbon storage from forests, forest hydrology becomes equally critical to sustainably providing services while protecting water resources.

Compared to Sanger sequencing, next-generation sequencing offers advantages for high resolution HLA genotyping including increased throughput, lower cost, and reduced genotype ambiguity. Here we describe an enhancement of the Roche 454 GS GType HLA genotyping assay to provide very high resolution (VHR) typing, by the addition of 8 primer pairs to the original 14, to genotype 11 HLA loci. These additional amplicons help resolve common and well-documented alleles and exclude commonly found null alleles in genotype ambiguity strings. Simplification of workflow to reduce the initial preparation effort using early pooling of amplicons or the Fluidigm Access Array™ is also described. Performance of the VHR assay was evaluated on 28 well characterized cell lines using Conexio Assign MPS software which uses genomic, rather than cDNA, reference sequence. Concordance was 98.4%; 1.6% had no genotype assignment. Of concordant calls, 53% were unambiguous. To further assess the assay, 59 clinical samples were genotyped and results compared to unambiguous allele assignments obtained by prior sequence-based typing supplemented with SSO and/or SSP. Concordance was 98.7% with 58.2% as unambiguous calls; 1.3% could not be assigned. Our results show that the amplicon-based VHR assay is robust and can replace current Sanger methodology. Together with software enhancements, it has the potential to provide even higher resolution HLA typing.

The landscape of the coastal plain of the southeastern United States is rapidly changing due to urbanization and climate‐change‐related impacts. In addition to the forecasted population increase, this region could experience significant changes in precipitation patterns making watershed management very challenging. In order to establish baseline data, storm‐event flow pathways were studied in three lower coastal plain (LCP) forested lowland watersheds of the southeastern United States between 2010 and 2011. Two of the watersheds had clay loam subsoils while the third had sandy soils throughout the profile. Stream flow and water samples from water‐table wells, piezometers, lysimeters, and rain gauges were analyzed for ion concentrations; ion trends were assessed using principal components analysis; and chemical hydrograph separation was performed for nine storm events using end‐member mixing analysis. End‐members consisted of lower concentration rainwater; a near‐stream source (riparian or streambed groundwater); and a distant or deep groundwater source. Storm‐event stream water on the clayey sites was composed primarily of rainwater (45–67% by volume) and shallow groundwater (21–55%), with small inputs from deep (below the clay‐rich soil horizon) groundwater (0.2–21%). At the sandy site, a greater proportion was groundwater (56–61%), with smaller inputs from rainwater (28–33%) and soil water (6–16%). Dry antecedent soil moisture (ASM) conditions and larger storms resulted in greater rainwater contribution at the clayey sites. Shallow groundwater was an important contributor even in dry ASM conditions, perhaps due to the high specific retention of the soils. The results from this study will inform researchers about stormwater routing in forested, shallow water table watersheds and provide land managers with baseline data as they plan stormwater mitigation practices.

Recent major wildres may result from a combination of climate change and fuel buildup due to re exclusion policies of the last century. Are such