scholarly journals Long-term assessment of floodplain reconnection as a stream restoration approach for managing nitrogen in ground and surface waters

2022 ◽  
Author(s):  
Paul M. Mayer ◽  
Michael J. Pennino ◽  
Tammy A. Newcomer-Johnson ◽  
Sujay S. Kaushal
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Stream Restoration ◽  
Specific Conductance ◽  
Data Set ◽  
N Transformations ◽  
Total N ◽  
Floodplain Reconnection ◽  
Over Time

AbstractStream restoration is a popular approach for managing nitrogen (N) in degraded, flashy urban streams. Here, we investigated the long-term effects of stream restoration involving floodplain reconnection on riparian and in-stream N transport and transformation in an urban stream in the Chesapeake Bay watershed. We examined relationships between hydrology, chemistry, and biology using a Before/After-Control/Impact (BACI) study design to determine how hydrologic flashiness, nitrate (NO3−) concentrations (mg/L), and N flux, both NO3− and total N (kg/yr), changed after the restoration and floodplain hydrologic reconnection to its stream channel. We examined two independent surface water and groundwater data sets (EPA and USGS) collected from 2002–2012 at our study sites in the Minebank Run watershed. Restoration was completed during 2004 and 2005. Afterward, the monthly hydrologic flashiness index, based on mean monthly discharge, decreased over time from 2002 and 2008. However, from 2008–2012 hydrologic flashiness returned to pre-restoration levels. Based on the EPA data set, NO3− concentration in groundwater and surface water was significantly less after restoration while the control site showed no change. DOC and NO3− were negatively related before and after restoration suggesting C limitation of N transformations. Long-term trends in surface water NO3− concentrations based on USGS surface water data showed downward trends after restoration at both the restored and control sites, whereas specific conductance showed no trend. Comparisons of NO3− concentrations with Cl− concentrations and specific conductance in both ground and surface waters suggested that NO3− reduction after restoration was not due to dilution or load reductions from the watershed. Modeled NO3− flux decreased post restoration over time but the rate of decrease was reduced likely due to failure of restoration features that facilitated N transformations. Groundwater NO3− concentrations varied among stream features suggesting that some engineered features may be functionally better at creating optimal conditions for N retention. However, some engineered features eroded and failed post restoration thereby reducing efficacy of the stream restoration to reduce flashiness and NO3− flux. N management via stream restoration will be most effective where flashiness can be reduced and DOC made available for denitrifiers. Stream restoration may be an important component of holistic watershed management including stormwater management and nutrient source control if stream restoration and floodplain reconnection can be done in a manner to resist the erosive effects of large storm events that can degrade streams to pre-restoration conditions. Long-term evolution of water quality functions in response to degradation of restored stream channels and floodplains from urban stressors and storms over time warrants further study, however.

scholarly journals Long-term Assessment of Floodplain Reconnection as a Stream Restoration Approach for Managing Nitrogen in Groundwater and Surface Water

2021 ◽  
Author(s):  
Paul Mayer ◽  
Michael Pennino ◽  
Tammy Newcomer-Johnson
Keyword(s):  
Surface Water ◽  
Watershed Management ◽  
Stream Restoration ◽  
Specific Conductance ◽  
Urban Stream ◽  
Source Control ◽  
Long Term Effects ◽  
N Removal ◽  
Over Time

Abstract Stream restoration is a popular approach for managing nitrogen in degraded, flashy urban streams. Here, we investigated the long-term effects of geomorphic stream restoration on riparian and in-stream N transport and transformation in an urban stream in the Chesapeake Bay watershed. We examined relationships between hydrology, chemistry, and biology using a Before/After-Control/Impact (BACI) study design to determine how flashiness and N concentrations and flux changed after the restoration. We examined two independent surface water and groundwater data sets collected from 2002–2012 at our study sites in the Minebank Run watershed, modeled N flux, and compared our data to similar long-term data from the Baltimore Ecosystem Study LTER (BES) that served as reference sites. Restoration was completed during 2004 and 2005. Afterward, the monthly flashiness index, based on mean monthly discharge, decreased over time from 2002 and 2008. Groundwater nitrate (NO3−) concentrations trended slightly downward over time after the restoration at the restored site while dissolved organic carbon (DOC) concentrations trended upward whereas no trends were observed at the control site. Comparisons of NO3− concentrations with Cl− concentrations and specific conductance in both groundwater and surface water suggested that N reductions over time at the restored sites were not due to dilution. Similar patterns at BES sites suggested that declining NO3− was a function of restoration and watershed management, not larger regional factors such as decreased atmospheric inputs. DOC and NO3− were negatively related before and after restoration suggesting C limitation of N transformation. Long-term trends in surface water NO3− based on USGS data showed downward trends after restoration at both the restored and control sites while specific conductance showed no trend, suggesting that load reductions were not responsible for NO3− patterns. Modeled NO3− flux decreased post restoration in both the short and long-terms. Groundwater NO3− concentrations varied among stream features suggesting that some engineered features may be functionally better at creating optimal conditions for N removal. However, some engineered features eroded and failed post restoration thereby reducing efficacy of the restoration to reduce flashiness and NO3− flux. N management via stream restoration will be most effective where flashiness can be reduced, and DOC made available for denitrifiers. Stream restoration may be an important component of holistic watershed management including stormwater management and nutrient source control.

scholarly journals Investigating the Broken-Heart Effect: a Model for Short-Term Dependence between the Remaining Lifetimes of Joint Lives

2012 ◽  
Vol 7 (2) ◽  
pp. 236-257 ◽  
Author(s):  
Jaap Spreeuw ◽  
Iqbal Owadally
Keyword(s):  
Mortality Rates ◽  
Short Term ◽  
Numerical Work ◽  
Data Set ◽  
Multiple State ◽  
Multiple State Model ◽  
Insurance Data ◽  
Over Time ◽  
Assurance Contracts

AbstractWe analyze the mortality of couples by fitting a multiple state model to a large insurance data set. We find evidence that mortality rates increase after the death of a partner and, in addition, that this phenomenon diminishes over time. This is popularly known as a “broken-heart” effect and we find that it affects widowers more than widows. Remaining lifetimes of joint lives therefore exhibit short-term dependence. We carry out numerical work involving the pricing and valuation of typical contingent assurance contracts and of a joint life and survivor annuity. If insurers ignore dependence, or mis-specify it as long-term dependence, then significant mis-pricing and inappropriate provisioning can result. Detailed numerical results are presented.

scholarly journals Deeper waters are changing less consistently than surface waters in a global analysis of 102 lakes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rachel M. Pilla ◽  
Craig E. Williamson ◽  
Boris V. Adamovich ◽  
Rita Adrian ◽  
Orlane Anneville ◽  
...  
Keyword(s):  
Surface Water ◽  
Average Rate ◽  
Thermal Structure ◽  
Global Analysis ◽  
Regional Climate ◽  
Data Set ◽  
Water Column Stability ◽  
Temperature Trends ◽  
Lake Characteristics

AbstractGlobally, lake surface water temperatures have warmed rapidly relative to air temperatures, but changes in deepwater temperatures and vertical thermal structure are still largely unknown. We have compiled the most comprehensive data set to date of long-term (1970–2009) summertime vertical temperature profiles in lakes across the world to examine trends and drivers of whole-lake vertical thermal structure. We found significant increases in surface water temperatures across lakes at an average rate of + 0.37 °C decade−1, comparable to changes reported previously for other lakes, and similarly consistent trends of increasing water column stability (+ 0.08 kg m−3 decade−1). In contrast, however, deepwater temperature trends showed little change on average (+ 0.06 °C decade−1), but had high variability across lakes, with trends in individual lakes ranging from − 0.68 °C decade−1 to + 0.65 °C decade−1. The variability in deepwater temperature trends was not explained by trends in either surface water temperatures or thermal stability within lakes, and only 8.4% was explained by lake thermal region or local lake characteristics in a random forest analysis. These findings suggest that external drivers beyond our tested lake characteristics are important in explaining long-term trends in thermal structure, such as local to regional climate patterns or additional external anthropogenic influences.

Characterising the airtightness of dwellings

2019 ◽  
Vol 38 (1) ◽  
pp. 89-106 ◽  
Author(s):  
Minnie M.A. Ashdown ◽  
Jenny Crawley ◽  
Phillip Biddulph ◽  
Jez Wingfield ◽  
Robert Lowe ◽  
...  
Keyword(s):  
Test Results ◽  
Reinforced Concrete Frame ◽  
Construction Technique ◽  
Data Set ◽  
Content Type ◽  
Timber Frame ◽  
Concrete Frame ◽  
Construction Methods ◽  
Over Time

Purpose The purpose of this paper is to investigate the distribution of dwelling airtightness test results for a developer, between 2007 and 2011. The changes in airtightness test results over time are discussed, and links between the airtightness test results and the construction technique are investigated. Design/methodology/approach A data set of airtightness test results was statistically analysed by applying probabilistic model of the distribution and using Bayesian parameter estimation techniques. Findings The inferred background distributions, those estimated to describe dwelling performance before secondary sealing, suggest an improvement in airtightness between 2008 and 2011, the mode decreases from 5.46±0.09 m3/m2h to 4.12±0.07 m3/m2h with a corresponding shift in practice towards a more target-driven approach. The most airtight dwellings are constructed from reinforced concrete frame, followed by “traditional” (dry lined masonry), timber frame and lightweight steel frame. Research limitations/implications This study is limited by the size of the available data set (901 dwellings), and by the fact that the data set contains a larger proportion of flats to houses; however, the metadata has enabled the exploration of the link between construction practices and airtightness. Practical implications Developers need better guidance surrounding how to meet more stringent airtightness requirements through improvements to the primary air barrier, with incentives and support to deliver changes in practice. Furthermore, if a large number of dwellings undergo secondary sealing, this may have implications for the long-term efficiency of the dwelling stock. Originality/value This analysis investigates two issues that have not previously been studied on a significant number of dwellings: the changes to the distribution of airtightness results over time and the link between construction methods and airtightness.

Empirical model for predicting a catchment-scale metric of surface water transit time in streams

2005 ◽  
Vol 62 (3) ◽  
pp. 492-504 ◽  
Author(s):  
Erwin E Van Nieuwenhuyse
Keyword(s):  
Surface Water ◽  
Transit Time ◽  
Longitudinal Velocity ◽  
Hydraulic Geometry ◽  
Catchment Scale ◽  
Data Set ◽  
Velocity Gradients ◽  
Average Water ◽  
Bivariate Regression

Estimates of average water velocity (vw) extracted from tracer dye studies (vdye) or calculated from velocity–discharge relationships at continuous-flow gauges (vgage) were combined with catchment area (A) and other readily available data for 111 streams throughout the conterminous United States. The resulting data set (n = 305) represented broad ranges of A (65 – 62 419 km2), mainstem length (Lmax, 15.6–867 km), slope (S, 0.14–11.5 m·km–1), and daily average discharge (Q, 0.09–634 m3·s–1). A catchment-scale metric of surface water transit time (Tw, Lmaxvdye–1) ranged from 0.3 to 40 days, averaging 7.2 days. A bivariate regression model using log10 A and log10 Q explained 83% of the variation in log10 Tw and predicted Tw with an average precision of ±49%. By contrast, a previously published model based on hydraulic geometry relationships overestimated Tw by 100%. Application of my model to five streams nested in a ninth-order (ω = 9) catchment indicated that under dry (September) and wet (March), long-term (1954–2001) median flow conditions, vw increased with Q (vw ∝ Q0.3) as far downstream as ω = 8 and then remained constant or declined. The slope of this longitudinal vw–Q relationship was three times greater than the expected value. Longitudinal velocity gradients in many streams may thus be much steeper than commonly assumed.

scholarly journals Long-Term X-ray Variability of Circinus X-1 as Observed by the RXTE All Sky Monitor

2003 ◽  
Vol 214 ◽  
pp. 218-219
Author(s):  
Junfeng Wang ◽  
W. N. Brandt
Keyword(s):  
Timing Analysis ◽  
Period Change ◽  
Light Curves ◽  
Data Set ◽  
X Ray ◽  
Low Mass ◽  
Sky Monitor ◽  
Radio Band ◽  
Over Time

The luminous low mass X-ray binary Cir X-1 has been observed nearly continuously for about 5 years by the X-ray All Sky Monitor on board the RXTE satellite. We carried out a timing analysis on Cir X-1 with the RXTE data. We define the period from the X-ray data, comparing the period change over time with the best current ephemeris. with folded light curves of entire data set, characteristics of the system like long-term lightcurve changes, behavior of flares and dips and super-Eddington accretion were obtained. We also checked and identified the secondary flaring reported in radio band with X-ray data.

scholarly journals Long-term growth trends in northern Wisconsin walleye populations under changing biotic and abiotic conditions

2018 ◽  
Vol 75 (5) ◽  
pp. 733-745 ◽  
Author(s):  
Eric J. Pedersen ◽  
Daisuke Goto ◽  
Jereme W. Gaeta ◽  
Gretchen J.A. Hansen ◽  
Greg G. Sass ◽  
...  
Keyword(s):  
Growth Rates ◽  
Largemouth Bass ◽  
Average Length ◽  
Micropterus Salmoides ◽  
Ecological Factors ◽  
Ecological Change ◽  
Catch Per Unit Effort ◽  
Data Set ◽  
Over Time

Walleye (Sander vitreus) populations are declining in Wisconsin and neighboring regions, motivating broader interest in walleye biology amidst ecological change. In fishes, growth integrates variation in ecological drivers and provides a signal of changing ecological conditions. We used a 23-year data set of length-at-age from 353 walleye populations across Wisconsin to test whether walleye growth rates changed over time and what ecological factors best predicted these changes. Using hierarchical models, we tested whether spatiotemporal variation in walleye growth was related to adult walleye density (density-dependent effects), water temperature, and largemouth bass (Micropterus salmoides) catch per unit effort (CPUE; predator or competitor effects). The average length of young walleye increased over time, and as a result, time to reach harvestable size declined significantly. In contrast, average lengths of older walleye have remained relatively constant over time. Juvenile walleye length-at-age was positively correlated with largemouth bass CPUE and surface water temperatures, but negatively correlated with adult walleye density. Our finding of widespread and long-term changes in walleye growth rates provides additional insights into how inland fisheries are responding to environmental change.

Combining Ecohydrological Catchment Modelling and Water Quality Monitoring to Assess Surface Water Pollution in the Swist River Basin

2020 ◽  
Author(s):  
Alexander Ahring ◽  
Marvin Kothe ◽  
Christian Gattke ◽  
Ekkehard Christoffels ◽  
Bernd Diekkrüger
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
River Basin ◽  
Surface Waters ◽  
Water Quality Monitoring ◽  
Pollutant Emissions ◽  
Quality Monitoring ◽  
Monitoring Data ◽  
Quality Data

<p>Inland surface waters like rivers, streams, lakes and reservoirs are subject to anthropogenic pollutant emissions from various sources. These emissions can have severe negative impacts on surface water ecology, as well as human health when surface waters are used for recreational activities, irrigation of cropland or drinking water production. In order to protect aquatic ecosystems and freshwater resources, the European Water Framework Directive (WFD) sets specific quality requirements which the EU member states must meet until 2027 for every water body.</p><p>Implementing effective measures and emission control strategies requires knowledge about the important emission pathways in a given river basin. However, due to the abundance of pollution sources and the heterogeneity of emission pathways in time and space, it is not feasible to gain this knowledge via water quality monitoring alone. In our study, we aim to combine SWAT ecohydrological modelling and long term water quality monitoring data to establish a spatially differentiated nitrogen emission inventory on the sub-catchment scale. SWAT (short for Soil and Water Assessment Tool) is a semi-distributed, dynamic and process-driven watershed model capable of simulating long term hydrology as well as nutrient fluxes on a daily time step.</p><p>The study area is the Swist river basin in North Rhine-Westphalia (Germany). Belonging to the Rhine river system, the Swist is the largest tributary of the Erft River and drains a basin area of approximately 290 km². As part of its legal obligations and research activities, the Erftverband local waterboard collects a large variety of long term monitoring data in the Swist river catchment, which is available for this study. This includes operational data from the wastewater treatment plants in the watershed, discharge data from four stream gauging stations, river water quality data from continuous and discontinuous monitoring, groundwater quality data as well as quality data from surface, sub-surface and tile drainage runoff from various land uses.</p><p>Our contribution will be made up of two equal parts: First, we will present our water quality monitoring activities in the catchment and the related data pool outlined above, with special emphasis on recent monitoring results from agricultural tile drainages. Apart from nutrients and other pollutants, the data suggests considerable inputs of herbicide transformation products like Chloridazon-Desphenyl (maximum concentration measured: 15 µg/l) via this pathway. Second, we will explain how we integrate the monitoring data into the SWAT simulations and how we tackle related challenges like parameter equifinality (meaning that multiple parameter sets can yield similar or identical model outputs). The overall goal is to take all possible emission pathways into consideration, including those often neglected in past SWAT studies, like tile drainages and combined sewer overflows (CSO). As the Swist catchment is affected by groundwater extraction due to lignite mining in the Lower Rhine Bay area, we will discuss how this is considered during SWAT model setup and calibration, and will present first simulation results concerning catchment hydrology.</p>

scholarly journals P220 An updated safety profile of baricitinib for the treatment of RA up to 7 years

Rheumatology ◽  
2020 ◽  
Vol 59 (Supplement_2) ◽  
Author(s):  
David Walker ◽  
Ilias Kouris ◽  
Thorsten Holzkämper ◽  
Marco W Wu ◽  
Ricardo Xavier ◽  
...  
Keyword(s):  
Safety Profile ◽  
Opportunistic Infections ◽  
Janus Kinase ◽  
Major Adverse Cardiovascular Events ◽  
Integrated Analysis ◽  
Data Set ◽  
Serious Infections ◽  
Geographical Regions ◽  
Over Time

Abstract Background Baricitinib (BARI) is a selective inhibitor of janus kinase (JAK) 1 and JAK2, approved for the treatment of moderately to severely active rheumatoid arthritis (RA) in adults in over 50 countries. Objective: To evaluate the long-term safety of BARI in patients with RA with a specific focus on malignancies, major adverse cardiovascular events (MACE), serious infections and herpes zoster (HZ) events. Methods Data from nine completed studies (5 Phase 3, 3 Phase 2, 1 Phase 1b) and 1 long term extension (LTE) study were pooled for this analysis (data cut-off date: 13-Feb-2018). The all BARI data set included all patients exposed to any BARI dose. Results A total of 3,770 patients with RA were treated with BARI (10,127 patient years [PY]) with a maximum exposure of 7 years. Of these, 2,938 (78%) and 1,754 (47%) were on concomitant methotrexate or corticosteroids (CS; mean dose 6.2 mg/day), respectively. The incidence rates (IR) of malignancy (excluding non-melanoma skin cancer) were 0.8 (2-mg) and 1.0 (4-mg; as-randomized analysis) in the LTE. The IRs for MACE were similar between the all BARI and PBO group; however, the IR for DVT/PE were numerically higher in the BARI 4mg group during the PBO-controlled period. IRs for MACE remain stable over time. The IR of serious infections were numerically higher in the PBO group; the IR of tuberculosis and other opportunistic infections were similar between the all BARI and PBO group. During the PBO-controlled period, HZ IR was significantly higher for BARI 4-mg versus PBO (4.4 vs 1.1) (Table 1). Amongst 323 HZ patients, 11 (4%) had received prior HZ vaccination. Twenty-six [8%] cases were multidermatomal, and no visceral disease was reported. Multivariate analyses showed that older age and some geographical regions (Asia, especially Japan, Taiwan and South Korea) were associated with a higher risk of HZ. Conclusion This integrated analysis in patients with active RA exposed to BARI for up to 7 years shows that the safety profile of BARI is like that reported previously. The IRs of malignancies, MACE (including DVT/PE), serious infection, and HZ did not increase over time. Disclosures D. Walker: Honoraria; Lilly, Pfizer, Giliad, Novartis, Roche. Member of speakers’ bureau; Lilly, Pfizer, Roche. I. Kouris: Other; Lilly employee. T. Holzkämper: Shareholder/stock ownership; Lilly. Other; Lilly employee. M.W. Wu: Other; Lilly employee. R. Xavier: None. J. Smolen: Consultancies; Abbvie, Amgen, Astra Zeneca, Astro, BMS. Grants/research support; Abbvie, Eli Lilly, Novartis, Pfizer, Roche, Samsung, Sanofi-Aventis, UCB. P. Durez: Member of speakers’ bureau; Abbvie, BMS, Celltrion, Eli Lilly. Y. Chen: None. J. Zhong: Corporate appointments; Eli Lilly Contractor. R. Liao: Other; Lilly employee. M.C. Genovese: Consultancies; Eli Lilly. K. Winthrop: Consultancies; Pfizer, UCB, Eli Lilly, Gilead, Abbvie, Roche, BMS.

Comparaison du climat marin de Grande-Rivière (baie des Chaleurs) avec celui d'autres stations de la côte atlantique

1965 ◽  
Vol 22 (6) ◽  
pp. 1321-1334 ◽  
Author(s):  
Par L. M. Lauzier ◽  
A. Marcotte
Keyword(s):  
Nova Scotia ◽  
Surface Water ◽  
Water Temperature ◽  
Surface Waters ◽  
East Coast ◽  
Surface Water Temperature ◽  
Temperature Variations ◽  
Marine Climate ◽  
Long Term Variations

Temperature variations of surface waters at Grande-Rivière have been studied in order to describe the marine climate of the region and to show anomalies between 1938 and 1962. Monthly averages of surface temperatures at Grande-Rivière vary between −1.5 and 14.0 C from February to August, respectively, yielding an annual mean of 5.0 C. Temperatures of surface waters are lower than 4.0 C during approximately 6 months of the year. Monthly averages are always higher at Entry Island than at Grande-Rivière and higher at Borden than at Entry Island. Summertime difference in temperature reaches 3.0 C between Entry Island and Grande-Rivière and 5.0 C between Borden and Grande-Rivière. Warm or cold years at Borden and at Entry Island are not necessarily warm or cold at Grande-Rivière.Heat exchanges at the surface and between layers and advection of heat are taken into consideration to explain the local variations of the marine climate at various parts of the Gulf of St. Lawrence. Long-term variations of surface water temperature at Grande-Rivière are compared with those observed at other points along Canada's east coast. Such variations at Grande-Rivière are similar to those of the waters off Nova Scotia. However, they seem to be different from those of other areas of the Magdalen Shallows where warming continues over a longer period than at Grande-Rivière.

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