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Although many climate predictions suggest that the frequency and intensity of large storm events might increase in the coming decades, few studies document the full impact of such events along their path. Here, we synthesize information on the impact of Hurricane Irene (formed August 21 2011) and Tropical Storm Lee (formed August 30, 2011) on erosion and sediment transport, lake metabolism, riparian hydrology and biogeochemistry, and stream water quality, from North Carolina to Maine. In almost all cases, these storms generated unprecedented changes in water quality (concentrations, loads), from tenfold increases in DOC and 100-fold increases in POC in Maryland, to 100-fold increases in TSS concentrations in Pennsylvania. Overbank flooding and up to 200-year streamflow events were recorded in New York and Vermont. In many cases, particulate loads (e.g. POC, PP, TSS) occurring during Irene and Lee represented more than 30% of the annual load. The dominance of particulate exports over solutes during Irene and Lee is consistent with the mobilization of normally immobile sediment pools, and massive erosion as reported at many locations across the Northeastern US. Several studies reported long lasting (> 1 year) effects of Irene and Lee on cyanobacterial blooms, erosion, or stream suspended sediment concentrations. However, this review also highlighted the lack of a consistent strategy in terms of methods, and measured water quality parameters. This strongly hinders our ability to fully assess the large-scale impact of such events on our environment, and ultimately their impact on our economy and society.

Nitrogen (N) inputs to coastal ecosystems have significant impacts on coastal community structure. In N limited systems, increases in N inputs may lead to excess productivity and hypoxia. Like many temperate estuaries, Long Island Sound (LIS), a major eastern U.S. estuary, is a N limited system which has experienced seasonal hypoxia since the 1800s. This study is the first effort to constrain the total N cycle in this estuary. The approach utilizes data collected over the last two decades in the LIS time series with hydrodynamic model results to generate both monthly and annual N budgets between 1995 and 2016. Of the total N that is delivered to LIS through rivers and atmospheric inputs, 40% is exported to the adjacent continental shelf on the order of 10.8 ± 8.9 × 106 kg N/year. Of this export, 41% is dissolved organic N, 29% is particulate organic N, 32% is nitrate + nitrite, and −3% is ammonium. The remaining 60% of the N delivered to LIS is either buried in sediments or lost through denitrification. This inferred internal loss rate is equivalent to 5.4 g N/(m2year). This study serves as an example of the significant inter-annual variations that estuarine budgets undergo as efforts to understand coastal biogeochemical cycles move forward.

Long Island Sound (LIS) is a relatively shallow estuary with a mean depth of 20 m (maximum depth 49 m) and a unique hydrology and history of pollutant loading. These factors have contributed to a wide variety of contamination problems in its muddy sediments, aquatic life, and water column. The LIS sediments are contaminated with toxic compounds and elements related to past and present wastewater discharges and runoff. These include nonpoint and stormwater runoff and groundwater discharges, whose character has changed over the years along with the evolution of its watershed and industrial history. Major impacts have resulted from the copious amounts of nutrients discharged into LIS through atmospheric deposition, domestic and industrial waste water flows, fertilizer releases, and urban runoff. All these sources and their effects are in essence the result of human presence and activities in the watershed, and the severity of pollutant loading and their impacts generally scales with total population in the watersheds surrounding LIS. Environmental legislation passed since the mid-to-late 1900s (e.g., Clean Air Act, Clean Water Act) has had a beneficial effect, however, and contaminant loadings for many toxic organic and inorganic chemicals and nutrients have diminished over the last few decades (O’Shea and Brosnan 2000; Trench et al. 2012; O’Connor and Lauenstein 2006; USEPA 2007). Major strides have been made in reducing the inflow of nutrients into LIS, but cultural eutrophication is still an ongoing problem and nutrient control efforts will need to continue. Nonetheless, LIS is still a heavily human impacted estuary (an “Urban Estuary,” as described for San Francisco Bay by Conomos 1979), and severe changes in water quality and sediment toxicity as well as ecosystem shifts have occurred since the European colonization in the early 1600s (Koppelman et al., 1976). The Sound has seen the most severe environmental changes over the last 400 years during its 10,000 year history (Lewis, this volume), suggesting that human impacts have overwhelmed the natural forces at play.

The hydrogeology and ground-water flow of the Muddy Brook riparian zone were investigated as part of a study to determine the effects of restoring agricultural riparian land to forest on water quality. Test-hole drilling, well installation, and slug-test analyses indicated that the part of Muddy Brook studied is underlain by thin stratified-drift deposits. These deposits are mostly less than 10 feet thick and have estimated horizontal hydraulic conductivities of 4 to 30 feet per day. Till deposits from 1 to 14 feet thick underlie the stratified-drift deposits and have estimated horizontal hydraulic conductivities of 0.1 to 4.3 feet per day. The water table in stratified drift is less than 10 feet below land surface during most of the year, and the horizontal hydraulic gradient varies seasonally and areally from 0.015 to 0.07 foot per foot. The horizontal hydraulic gradient in the till deposits is as great as 0.1 foot per foot. Vertical hydraulic gradients of as large as 0.4 foot per foot are present between the till and stratified drift and are predominantly upward from the till into the stratified drift but can reverse direction in response to recharge. Ground-water discharge to Muddy Brook comes mostly from the saturated stratified-drift deposits, and during April through September 1992, flowed at a rate of 0.015 to 0.027 cubic feet per second. Average ground-water velocity is about 1 feet per day in the stratified drift and about 0.2 foot per day through the till deposits. Discharge of ground water from the till can contribute as much as 0.006 cubic feet per second of water to the stratified drift. INTRODUCTION Nonpoint-source contamination of surface water and ground water has become a major water-quality issue in Connecticut. Nutrient loading is believed to be the cause of hypoxic conditions, which occur seasonally in some sections of Long Island Sound. It was estimated that 4,900 tons per year, or 24 percent, of the nitrogen input from rivers to Long Island Sound can be attributed to anthropogenic nonpoint sources (Long Island Sound Study, 1990). Recent studies have shown that high concentrations of nitrogen, in the form of nitrate, are present in the ground water beneath agricultural areas (Mullaney and others, 1991; Grady, 1994). The maintenance and restoration of forested riparian zones to filter or remove nutrients from surface runoff and ground water have been proposed by the Connecticut Department of Environmental Protection (DEP) as a method of decreasing nonpointsource contamination (Connecticut Department of Environmental Protection, 1989). A study of the effects of restoring agricultural riparian land to a native forest on water quality was initiated in 1992 by the University of Connecticut, College of Agriculture and Natural Resources. The study objectives were to (1) evaluate the effect of establishing a forested riparian zone on existing cropland on surface and ground-water quality and (2) demonstrate, in cooperation with Federal and State regulatory agencies, the effectiveness of restoring a forested riparian zone, thus showing it to be a Best Management Practice (BMP). The need to characterize the hydrogeology and the ground-water-flow system in the study area was identified by University of Connecticut researchers and the DEP. Consequently, the U.S. Geological Survey (USGS) entered into a cooperative agreement with the DEP to investigate the hydrogeology of the study site and to determine a simple method to estimate ground-water flow. As a result of this study, more information is now available on the hydraulic properties of stratified-drift and till deposits in central Connecticut, and there is an increased understanding of ground-water flow in riparian areas.