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 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.

Long-term effects of preplant liming on apple trees and soil cation levels

1991 ◽  
Vol 71 (4) ◽  
pp. 545-549
Author(s):  
G. H. Neilsen ◽  
E. J. Hogue ◽  
P. B. Hoyt
Keyword(s):  
Calcium Hydroxide ◽  
Apple Tree ◽  
Sandy Loam ◽  
Long Term Effects ◽  
Apple Trees ◽  
Orchard Soil ◽  
Lime Application ◽  
Over Time ◽  
Key Words Apple

Nine years after liming a sandy loam orchard soil to pH 6.0 with calcium hydroxide or dolomitic lime, pH and extractable Ca and Mg were still higher where limed than where unlimed. However, pH had decreased below 5.0 in the limed and N-fertilized plots. Delicious (Malus domestica Borkh.) apple tree nutrition benefited from the two soil amendments. Leaf Mg was increased by dolomite. Leaf Ca was increased by calcium hydroxide. Leaf Mn, although highest in unlimed soils, increased over time for both limed and unlimed soil. Key words: Apple, lime application, reacidification

scholarly journals The Long-term Effects of Instruction on EFL Learners' Use of Complaining Formulas

10.29007/5xsb ◽  
2018 ◽  
Author(s):  
Alicia Martínez-Flor ◽  
Esther Usó-Juan
Keyword(s):  
Foreign Language ◽  
Language Learners ◽  
Future Research ◽  
Long Term Effects ◽  
Positive Role ◽  
Efl Learners ◽  
Foreign Language Learners ◽  
Over Time

Studies analysing the positive role of pragmatic instruction in formal settings have increased over the last decades. Within this area of interventional pragmatics, some studies have particularly examined whether the effectiveness of the instruction implemented is sustained over time. In order to shed more light on the long-term effects of instruction, this research investigates English as a Foreign Language learners’ use of complaining formulas not only after immediately receiving instruction, but also two months later. Results show that learners keep using a variety of appropriate complaining formulas two months after having participated in the instructional period. These findings are discussed and directions for future research suggested.

China's Economic Growth and Innovation in Globalization

2019 ◽  
pp. 1-27
Author(s):  
Bryan Christiansen
Keyword(s):  
Economic Integration ◽  
Capital Flows ◽  
Direct Investment ◽  
Chinese Economy ◽  
Business Organizations ◽  
Long Term Effects ◽  
Critical Determinant ◽  
National Economies ◽  
Over Time

The purpose of this chapter is to investigate the potential long-term effects of contemporary globalization on the Chinese economy and innovation in an era of global hypercompetition. Globalization today is basically accepted as the process that removes geographical boundaries and enables the economic integration and interdependence of national economies into the international economy through trade, foreign direct investment, migration, and capital flows. Since productivity remains the critical determinant of long-term national growth and prosperity, the effects of today's globalism on productivity demands the need for business organizations in particular to sustain a competitive advantage and to remain profitable over time. Based on an integrative literature review, this chapter explores why China must continue to develop its innovation capabilities as well as to provide opportunities for foreign businesses over the long-term via responsible economic development that also benefits the nation's domestic population.

The Final Score

2020 ◽  
pp. 201-210
Author(s):  
Steven M. Ortiz
Keyword(s):  
Lived Experience ◽  
Longitudinal Research ◽  
Long Term Effects ◽  
Professional Athlete ◽  
The Past ◽  
Personal Empowerment ◽  
Final Score ◽  
Short And Long Term ◽  
Over Time

The conclusion provides some final observations about the longitudinal research itself and its short- and long-term effects on the women involved. It briefly touches on the few areas of the sport marriage that have seen improvement in the past few decades, discusses the conscious decisions the women make to continue normalizing the career-dominated marriage, and reports on how the marriages fared over time. It also describes the women’s personal empowerment as a result of their participation in the research. Finally, it summarizes the advice and suggested keys to a successful sport marriage that the wives in both studies offered, based on their lived experience. This overview essentially describes how and why the wife of a male professional athlete must adapt to realities if she wants her marriage to survive her husband’s career and retirement.

scholarly journals Nitrate leaching and N2-fixation in grasslands of different composition, age and management

2004 ◽  
Vol 142 (2) ◽  
pp. 141-151 ◽  
Author(s):  
J. ERIKSEN ◽  
F. P. VINTHER ◽  
K. SØEGAARD
Keyword(s):  
Perennial Ryegrass ◽  
Nitrate Leaching ◽  
Dry Matter ◽  
Grazing Intensity ◽  
Dry Matter Production ◽  
Leaching Losses ◽  
N Removal ◽  
Matter Production ◽  
Over Time

Grass-legume associations may offer a way of improving the N efficiency of dairy farming, but may also have an adverse impact on the environment by increasing leaching losses. Nitrate leaching from four cropping sequences with different grassland frequency and management (long-term grazed, long-term cut, cereals followed by 1 and 2-year grazed leys) were investigated on a loamy sand in central Jutland for both unfertilized grass-clover (perennial ryegrass (Lolium perenne L.)/white clover (Trifolium repens L.)) and fertilized perennial ryegrass (300 kg N/ha) swards during 1997–2002. Furthermore, 1 year (2001) of N2 fixation in 1-, 2- and 8-year-old grass-clover pastures was determined. Nitrate leaching from grazed unfertilized grass-clover was always considerably lower than from grazed fertilized ryegrass. The effect of grassland age on nitrate leaching was insignificant in grass-clover but clear in grazed ryegrass, where levels increased dramatically with sward age. In production years 6–8, leaching from grass-clover was only 9–13% of the comparable losses from ryegrass. Under the cutting regime grass-clover showed a significant reduction in both yield and N-removal with increasing sward age, whereas for ryegrass these figures did not show any decreasing trend. N2 fixation was lower in 8-year-old swards compared with fully established 2-year-old swards as a consequence of lower dry matter production, lower clover content and a lower proportion of clover-N derived from the atmosphere. The results from the present study indicate that the higher leaching losses observed in fertilized grass compared with unfertilized grass-clover systems were caused by (1) a reduction in N2-fixation in grass-clover over time and (2) a reduction in dry matter production in grass-clover over time, lowering the grazing intensity and the recycling of grassland N via animal excreta.

scholarly journals UAV Monitoring of Stream Restorations

Hydrology ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 29 ◽  
Author(s):  
Jakub Langhammer
Keyword(s):  
Spatial Data ◽  
Stream Restoration ◽  
Riparian Zone ◽  
Qualitative Assessment ◽  
Urban Stream ◽  
Stream Channel ◽  
The Czech Republic ◽  
Restoration Monitoring ◽  
Unique Source

This study examines the potential and limits of the unmanned aerial vehicles (UAVs) applicability for the monitoring of stream restoration in an urban environment. UAV imaging was used for long-term post-restoration monitoring of an urban stream. The monitoring was aimed to track the stream changes significant for the assessment of the restoration success, such as the compliance of the restoration to the plan, stability and evolution of the stream channel, or changes in stream and riparian habitats. The recurrent imaging campaigns in the restored segment of Hostavicky brook in Prague, The Czech Republic, were undertaken for three years since the restoration using the DJI Inspire 1 Pro platform. The UAV monitoring revealed that the new stream pattern substantially differs from the proposed restoration plan. Despite this, the new channel has proved stability, supported by intense grassing of the floodplain, resulting in only marginal evolution of the restored channel. The new channel proved the ability to mitigate the course of a significant flood event without significant flood spills outside the riparian zone. The UAV monitoring also revealed intense eutrophication in newly created shallow ponds with insufficient drainage. The research proved that UAV imaging is a unique source of spatial data, providing reliable information for quantitative and qualitative assessment of the stream restoration progress and success.

When the Rich Don't Get Richer: Equalizing Tendencies of Creative Networks

Leonardo ◽  
2011 ◽  
Vol 44 (3) ◽  
pp. 260-261 ◽  
Author(s):  
John Bell ◽  
Jon Ippolito
Keyword(s):  
Online Environment ◽  
Long Term Effects ◽  
The Rich ◽  
User Ratings ◽  
Over Time

Analysis of the collaborative online environment The Pool suggests that inequalities in some creative networks may level out over time due to the long-term effects of user ratings.

scholarly journals Анализ навигационной аварии с использованием аппарата современной теории катастроф

2020 ◽  
Author(s):  
I.A. Yanchin
Keyword(s):  
Dynamic Characteristic ◽  
Catastrophe Theory ◽  
Evolutionary Dynamics ◽  
Geometric Interpretation ◽  
Estimation Technique ◽  
Long Term Effects ◽  
The Future ◽  
Over Time

В работе рассматривается метод оценки маршрута судна с точки зрения безопасности и оптимальности. Оценка выполняется за счёт вычисления характеристических коэффициентов, которые описывают свойства маршрута, важные для оценки этих качеств. Также в работе даётся описание метода прогнозирования дальнейшего маршрута судна на основе предписанного маршрута рейса и информации о существующем отклонении фактического маршрута от предписанного. На основе прогнозирования дальнейшего маршрута, и с использованием характеристических коэффициентов, становится возможным анализ долгосрочного влияния отклонения фактического маршрута от предписанного. Маршрут рассматривается как динамическая характеристика судна, эволюционирующая с течением времени. Обсуждаются особенности развития маршрута судна при стремлении к стабильному либо катастрофичному состоянию с позиций современной теории катастроф. Геометрическая интерпретация эволюционной динамики предусматривает использование когнитивных образов. В работе приводится анализ произошедшей аварии круизного судна Costa Concordia с использованием предложенного метода с целью исследования влияния изменения маршрута на безопасность рейса. Выполняется сравнение предписанного маршрута с фактическим.The paper presents a method to analyze a ships route in terms of safety and optimality. The route is examined using the characteristic coefficients that represent routes properties essential for assessment of these aspects. The paper also presents a method to estimate the future route based on the prescribed route and the existing discrepancy between the actual route and the prescribed one. With such estimation technique and using the characteristic coefficients it is possible to determine the long-term effects of the discrepancy. The route is considered as a dynamic characteristic of the ship, evolving over time. Peculiarities of the development of the ships route when striving for a stable or catastrophic state from the standpoint of the modern catastrophe theory are discussed. A geometric interpretation of evolutionary dynamics involves the use of cognitive images. As an example, the paper provides analysis of the Costa Concordias accident using the described method in order to determine the effects of the route discrepancy. A comparison is made of the prescribed route with the actual one that the crew planned to move.

scholarly journals Long-term watershed management is an effective strategy to reduce organic matter export and disinfection by-product precursors in source water

2019 ◽  
Vol 28 (10) ◽  
pp. 804 ◽  
Author(s):  
Hamed Majidzadeh ◽  
Huan Chen ◽  
T. Adam Coates ◽  
Kuo-Pei Tsai ◽  
Christopher I. Olivares ◽  
...  
Keyword(s):  
Organic Matter ◽  
South Carolina ◽  
Watershed Management ◽  
Management Practices ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Long Term Effects ◽  
Pyrolysis Gas ◽  
Water Extracts

Watershed management practices such as prescribed fire, harvesting and understory mastication can alter the chemical composition and thickness of forest detritus, thus affecting the quantity and quality of riverine dissolved organic matter (DOM). Long-term effects of watershed management on DOM composition were examined through parallel field and extraction-based laboratory studies. The laboratory study was conducted using detritus samples collected from a pair of managed and unmanaged watersheds in South Carolina, USA. Results showed that dissolved organic carbon (DOC), total dissolved nitrogen (TDN) and ammonium (NH4+-N) concentrations were higher in water extracts from the unmanaged watershed than from the managed watershed (P<0.01). Pyrolysis gas chromatography–mass spectrometry analysis showed that water extracts from the unmanaged watershed contained more aromatic compounds than extracts from the managed watershed. For the field study, monthly water samples were collected for 1 year (2015) from the paired watersheds. DOC and TDN concentrations, as well as DOM aromaticity, were significantly higher in the unmanaged watershed than in the managed watershed for most of the year (P<0.05) and were linked to detrital thickness, precipitation and flow patterns. The formation potential of two regulated disinfection by-products was lower in the unmanaged watershed for most of 2015 (P<0.05). From this study, it appears that long-term watershed management practices may alter detrital mass and chemistry in ways that improve water quality.

Sign in / Sign up

Export Citation Format

Share Document