Vulnerability of water resources under a changing climate and human activity in the lower Great Lakes region     

Jenny T. Soonthornrangsan  Christopher S. Lowry 《水文研究》2021,35(12):e14440

Globally, the number of people experiencing water stress is expected to increase by millions by the end of the century. The Great Lakes region, representing 20% of the world's surface freshwater, is not immune to stresses on water supply due to uncertainties on the impacts of climate and land use change. It is imperative for researchers and policy makers to assess the changing state of water resources, even if the region is water rich. This research developed the integrated surface water-groundwater GSFLOW model and investigated the effects of climate change and anthropogenic activities on water resources in the lower Great Lakes region of Western New York. To capture a range of scenarios, two climate emission pathways and three land development projections were used, specifically RCP 4.5, RCP 8.5, increased urbanization by 50%, decreased urbanization by 50%, and current land cover, respectively. Model outputs of surface water and groundwater discharge into the Great Lakes and groundwater storage for mid- and late century were compared to historical to determine the direction and amplitude of changes. Both surface water and groundwater systems show no statistically significant changes under RCP 4.5 but substantial and worrisome losses with RCP 8.5 by mid-century and end of century. Under RCP 8.5, streamflow decreased by 22% for mid-century and 42% for late century. Adjusting impervious surfaces revealed complex land use effects, resulting in spatially varying groundwater head fluctuations. For instance, increasing impervious surfaces lowered groundwater levels from 0.5 to 3.8 m under Buffalo, the largest city in the model domain, due to reduced recharge in surrounding suburban areas. Ultimately, results of this study highlight the necessity of integrated modelling in assessing temporal changes to water resources. This research has implications for other water-rich areas, which may not be immune to effects of climate change and human activities.  相似文献   

Acidification recovery in a changing climate: Observations from thirty-five years of stream chemistry monitoring in forested headwater catchments at the Turkey Lakes watershed,Ontario     

Kara L. Webster  Jason A. Leach  Daniel Houle  Paul W. Hazlett  Erik J. S. Emilson 《水文研究》2021,35(9):e14346

Long-term ecosystem studies are valuable for understanding integrated ecosystem response to global changes in atmospheric deposition and climate. We examined trends for a 35-year period (1982/83–2017/18) in concentrations of a range of solutes in precipitation and stream water from nine headwater catchments spanning elevation and surficial geology gradients at the Turkey Lakes watershed (TLW) in northeastern Ontario, Canada. Average annual water year (WY, October to September) concentrations in precipitation significantly declined over the period for sulphate (SO₄²⁻), nitrate (NO₃⁻) and chloride (Cl⁻), while calcium (Ca²⁺) and potassium (K⁺) concentrations increased, resulting in a significant pH increase from 4.2 to 5.7. Trends in stream chemistry through time are generally consistent with expectations associated with acidification recovery. Concentration of many stream water solutes (SO₄²⁻, Cl⁻, calcium [Ca²⁺], magnesium [Mg²⁺] and NH₄⁺ generally decreased, while others (silica [SiO₂] and dissolved organic carbon [DOC]) generally increased. Increases were also observed for alkalinity (six of nine catchments), acid neutralizing capacity ([ANC]; six of nine catchments) and pH (eight of nine catchments), while conductivity declined (six of nine catchments). Variability in trends among catchments are associated with differences in surficial geology and wetland cover. While absolute solute concentrations were generally lower at bedrock dominated high-elevation catchments compared to till dominated lower elevation catchments, the rate of change of concentration was often greater for high elevation catchments. This study confirms continued, but non-linear stream chemistry recovery from acidification, particularly at the less buffered high and moderate elevation sites. The heterogeneity of responses among catchments highlights our incomplete understanding of the relative importance of different mechanisms influencing stream chemistry and the consequences for downstream ecosystems.  相似文献   

Isotope geochemistry of Swan Lake Basin in the Nebraska Sandhills,USA: Large 13C enrichment in sediment-calcite records     

《Chemie der Erde / Geochemistry》2014,74(4):681-690

This study presents isotope geochemical analyses conducted on water column samples and core sediments collected from the Swan Lake Basin. Water analyses include the dissolved methane (CH₄) content and the ratio of carbon-13 to carbon-12 (δ¹³C) in dissolved inorganic carbon (DIC). The core sediments – sandy muds containing inorganic calcite, organic matter, and opal phases ± ostracods – were examined by X-ray diffraction, dated by radiocarbon (¹⁴C), analyzed for wt% organic carbon, wt% organic nitrogen, wt% organic matter, wt% calcite, δ¹³C of bulk-sediment insoluble organic matter (kerogen), ¹⁸O:¹⁶O ratio (δ¹⁸O) and δ¹³C of bulk and ostracod calcite. Of particular significance is the large enrichment in carbon-13 (δ¹³C = +4.5 to +20.4‰ V-PDB) in the calcite of these sediments. The ¹³C-enriched calcite is primarily formed from DIC in the water column of the lake as a result of the following combined processes: (i) the incorporation of ¹³C enriched residual carbon dioxide (CO₂) after partial reduction to CH₄ in the sediments and its migration into the water column-DIC pool; (ii) the preferential assimilation of ¹²C by phytoplankton during photosynthesis; (iii) the removal of ¹³C-depleted CH₄ by ebullition and of organic matter by sedimentation and burial. The ¹³C enrichment was low between 3624 and 2470 yr BP; high between 2470 and 1299 yr BP; and moderate since 1299 yr BP. Low ¹³C enrichment was formed under low water-column carbon levels while higher ones were formed under elevated rates of biomass and calcite deposition. These associations seem to imply that biological productivity is the main reason for carbon-13 enrichments.  相似文献   

Holocene paleoclimates of India   总被引：4，自引：0，他引：4  

Sushma Prasad  Yehouda Enzel   《Quaternary Research》2006,66(3):442-453

We present a comprehensive summary of the available palaeoclimate records from India and compare the results from different proxies. The results indicate (i) fluctuating lake levels during the early Holocene. The period of relatively higher lake levels from increased precipitation efficiency was reached only 7.2–6.0 cal kyr BP, possibly due to increased contribution from winter rainfall; (ii) the onset of aridity in NW India could have begun as early as 5.3 cal kyr BP. Subsequently, there were multiple wet events but of shorter duration and smaller magnitude than during the mid Holocene; (iii) there is evidence of several short term climate events in the proxy record. However, in the absence of a rigorous chronological framework a detailed regional correlation is not possible at this stage. Finally, a comparison between marine and terrestrial records indicates that episodes of strongest and weakest monsoon winds were not always associated with wettest and driest episodes respectively in the NW Indian lakes.  相似文献   

Racetrack and Bonnie Claire: southwestern US playa lakes as analogs for Ontario Lacus, Titan     

Ralph D. Lorenz  Brian Jackson 《Planetary and Space Science》2010,58(4):724-731

We note the geomorphological and meteorological processes at Racetrack Playa, Death Valley National Park, as analogs for those at Ontario Lacus on Titan. Although Ontario is ∼50× larger, the planforms of the two features are nearly identical, both are extremely flat, and are in environments where infrequent rainfall occurs against a climate, where evaporation exceeds precipitation. While the famous moving rocks on the Racetrack Playa may be exceptional on the Earth, the lower gravity and thicker atmosphere may render wind-induced rock transport comparatively common on Titan. Nearby Bonnie Claire Playa also provides field insights into the interpretation of remote sensing data from Titan.  相似文献   

The dilution and dispersion of ballast water discharged into Goderich Harbor     

Wells MG  Bailey SA  Ruddick B 《Marine pollution bulletin》2011,62(6):1288-1296

Observations are presented on dilution and dispersion rates of ballast water discharged under normal operational conditions at the semi-enclosed port of Goderich, Ontario. The ballast water was tagged with Rhodamine-WT dye and microscopic magnetically-attractive tracer particles. Maximum concentrations of dye immediately after discharge were diluted to 1-5% of initial ballast tank concentrations, and within 3 days had decreased to less than 0.1% of initial concentrations. Inside the harbor, there was 10-20% of the ballast water still present after 2 days, consistent with a flushing rate of 0.8-1.15 day⁻¹. Magnetic particles were collected up to 7.5 km outside the harbor after one day, consistent with a dilution factor of order 10⁵ outside the harbor. The results of this study are discussed in the context of ballast water discharge standards proposed by the International Maritime Organization to minimize the introduction of aquatic nonindigenous species through ships’ ballast water and sediments.  相似文献   

Assessing landscape change in Waterton Lakes National Park,Canada, using multitemporal composites constructed from terrestrial repeat photographs     

Dawna L. Cerney  J. Ronald Eyton  David R. Butler 《国际地球制图》2013,28(5):347-371

The objective of this paper is to investigate landscape level changes that have occurred in Waterton Lakes National Park (WLNP), Canada between the years 1914 and 2005 using digital image processing techniques usually associated with satellite image analysis. Multitemporal colour composites, image classification, and principal components analysis were used to process registered images of the montane ecotone from photographic pairs of Bellevue Hill, Horseshoe Basin and Lakeview Ridge. The resulting digital images offered insight into the spatial nature of the vegetation changes that have occurred over the last 90 years at these sites. Changes observed included increased forest cover through vertical migration and the infill of conifers and aspen both on the slopes and the valley bottoms of WLNP.  相似文献   

THE MOST PERFECT EXAMPLE OF AN ALIEN ECOLOGY EVER CONSTRUCTED     

《The Professional geographer》2013,65(4):471-477

Much science-fiction literature is based upon the creation and exploration of alternative environments. Stanley G. Weinbaum's short story, “Parasite Planet,”introduces an unusual environment that may be wrong in the light of recent evidence on Venus but still stimulates the geographical imagination.  相似文献   

Impacts of projected climate change on sediment yield and dredging costs          下载免费PDF全文

Travis A. Dahl  Anthony D. Kendall  David W. Hyndman 《水文研究》2018,32(9):1223-1234

Changes in climate may significantly affect how sediment moves through watersheds into harbours and channels that are dredged for navigation or flood control. Here, we applied a hydrologic model driven by a large suite of climate change scenarios to simulate both historical and future sediment yield and transport in two large, adjacent watersheds in the Great Lakes region. Using historical dredging expenditure data from the U.S. Army Corps of Engineers, we then developed a pair of statistical models that link sediment discharge from each river to dredging costs at the watershed outlet. Although both watersheds show similar slight decreases in streamflow and sediment yield in the near‐term, by Mid‐Century, they diverge substantially. Dredging costs are projected to change in opposite directions for the two watersheds; we estimate that future dredging costs will decline in the St. Joseph River by 8–16% by Mid‐Century but increase by 1–6% in the Maumee River. Our results show that the impacts of climate change on sediment yield and dredging may vary significantly by watershed even within a region and that agricultural practices will play a large role in determining future streamflow and sediment loads. We also show that there are large variations in responses across climate projections that cause significant uncertainty in sediment and dredging projections.  相似文献   

Synoptic and meteorological conditions during extreme snow cover ablation events in the Great Lakes Basin     

Zachary J. Suriano 《水文研究》2020,34(8):1949-1965

Snow cover ablation in the Great Lakes basin is a common and hydrologically important process during the cold season, contributing to a majority of the basin's runoff, and less frequent, extreme ablation events are highly impactful due to an increased flooding risk and warrant specific investigation. A brief climatology of extreme ablation events is presented, where extreme is considered within the top 5% of the distribution. Using synoptic classification techniques, individual weather patterns associated with extreme snow ablation in the Great Lakes basin are isolated. A single pattern deemed the most influential in generating extreme ablation events, southerly flow-1, is examined in detail, and three case studies are presented to determine the meteorological conditions and surface energy fluxes responsible for ablation. Over 75% of extreme events are associated with southerly flow patterns that predominantly ablate snow with sensible heat fluxes, while rain-on-snow patterns induce the remaining extreme events from 1980–2009. Type southerly flow-1 is responsible for 45% of the extreme events and is characterized by strong southerly advection of warm air into the basin, where sensible heat fluxes of 45–125 Wm⁻² are responsible for the majority of energy transfer into the snowpack. When compared with an average ablation event, an extreme ablation event for southerly flow-1 exhibits air temperatures, dew point temperatures, and wind speeds that are 3.8°C, 3.0°C, and 1.2 ms⁻¹ warmer and faster than an average event, indicating a greater potential for larger ablation.  相似文献