scholarly journals Nitrogen concentrations in a small Mediterranean stream: 1. Nitrate 2. Ammonium

2002 ◽  
Vol 6 (3) ◽  
pp. 539-550 ◽  
Author(s):  
A. Butturini ◽  
F. Sabater
Keyword(s):  
Hyporheic Zone ◽  
Nitrate Concentration ◽  
Stream Water ◽  
Rate Of Change ◽  
Ammonium Concentration ◽  
Precipitation Regime ◽  
Concentration Variance ◽  
N Concentration ◽  
Storm Flow ◽  
Nitrogen Concentrations

Abstract. The importance of storm frequency as well as the groundwater and hyporheic inputs on nitrate (NO3-N) and ammonium (NH4-N) levels in stream water were studied in a small perennial Mediterranean catchment, Riera Major, in northeast Spain. NO3-N concentrations ranged from 0.15 to 1.9 mg l-1. Discharge explained 47% of the annual NO3-N concentration variance, but this percentage increased to 97% when single floods were analysed. The rate of change in nitrate concentration with respect to flow, ΔNO3-N/ΔQ, ranged widely from 0 to 20 μg NO3-N s l-2. The ΔNO3-N/ΔQ values fitted to a non linear model with respect to the storm flow magnitude (ΔQ) (r2=0.48, d.f.=22, P<0.01). High values of ΔNO3-N/ΔQ occurred at intermediate ΔQ values, whereas low ΔNO3-N/ΔQ values occurred during severe storms (ΔQ > 400 l s-1). N3-N concentrations exhibit anticlockwise hysteresis patterns with changing flow and the patterns observed for autumnal and winter storms indicated that groundwater was the main N3-N source for stream and hyporheic water. At baseflow, NO3-N concentration in groundwater was higher (t=4.75, d.f.=29, P>0.001) and co-varied with concentrations in the stream (r=0.91, d.f.=28, P<0.001). In contrast, NO3-N concentration in hyporheic water was identical to that in stream water. The role of the hyporheic zone as source or sink for ammonium was studied hyporheic was studied comparing its concentrations in stream and hyporheic zone before and after a major storm occurred in October 1994 that removed particulate organic matter stored in sediments. Results showed high ammonium concentrations (75±28 s.d. μg NH4-N l-1) before the storm flow in the hyporheic zone. After the storm, the ammonium concentration in the hyporheic dropped by 80% (13.6±8 μg N4-N l-1) and approached to the level found in stream water (11±8 μg NH4-N l-1) indicating that indisturbed hyporheic sediments act as a source for ammonium. After the storm, the ammonium concentrations in the stream, hyporheic and groundwater zones were very similar suggesting that stream ammonium concentrations are sustained mainly by input from groundwater. The present study provides evidence that storm flow magnitude is an important source of variability of nitrate concentration and fluxes in Mediterranean streams subjected to an irregular precipitation regime with prolonged dry periods.

scholarly journals Nitrogen circulation in a Mediterranean holm oak forest, La Castanya, Montseny, northeastern Spain

2002 ◽  
Vol 6 (3) ◽  
pp. 551-558 ◽  
Author(s):  
A. Avila ◽  
A. Rodrigo ◽  
F. Rodà
Keyword(s):  
Hyporheic Zone ◽  
Nitrate Concentration ◽  
Stream Water ◽  
Rate Of Change ◽  
Ammonium Concentration ◽  
Precipitation Regime ◽  
Concentration Variance ◽  
N Concentration ◽  
Storm Flow ◽  
Discharge Regime

Abstract. The importance of storm frequency as well as the groundwater and hyporheic inputs on nitrate (NO3-N) and ammonium (NH4-N) levels in stream water were studied in a small perennial Mediterranean catchment, Riera Major, in northeast Spain. NO3-N concentrations ranged from 0.15 to 1.9 mg l-1. Discharge explained 47% of the annual NO3-N concentration variance, but this percentage increased to 97% when single floods were analysed. The rate of change in nitrate concentration with respect to flow, ΔNO3-N/ΔQ, ranged widely from 0 to 20 μg NO3-N s l-2. The ΔNO3-N/ΔQ values fitted to a non linear model with respect to the storm flow magnitude (ΔQ) (r2=0.48, d.f.=22, P<0.01). High values of ΔNO3-N/ΔQ occurred at intermediate ΔQ values, whereas low ΔNO3-N/ΔQ values occurred during severe storms (ΔQ > 400 l s-1). N3-N concentrations exhibit anticlockwise hysteresis patterns with changing flow and the patterns observed for autumnal and winter storms indicated that groundwater was the main N3-N source for stream and hyporheic water. At baseflow, NO3-N concentration in groundwater was higher (t=4.75, d.f.=29, P>0.001) and co-varied with concentrations in the stream (r=0.91, d.f.=28, P<0.001). In contrast, NO3-N concentration in hyporheic water was identical to that in stream water. The role of the hyporheic zone as source or sink for ammonium was studied hyporheic was studied comparing its concentrations in stream and hyporheic zone before and after a major storm occurred in October 1994 that removed particulate organic matter stored in sediments. Results showed high ammonium concentrations (75±28 s.d. μg NH4-N l-1) before the storm flow in the hyporheic zone. After the storm, the ammonium concentration in the hyporheic dropped by 80% (13.6±8 μg N4-N l-1) and approached to the level found in stream water (11±8 μg NH4-N l-1) indicating that indisturbed hyporheic sediments act as a source for ammonium. After the storm, the ammonium concentrations in the stream, hyporheic and groundwater zones were very similar suggesting that stream ammonium concentrations are sustained mainly by input from groundwater. The present study provides evidence that storm flow magnitude is an important source of variability of nitrate concentration and fluxes in Mediterranean streams subjected to an irregular precipitation regime with prolonged dry periods. Keywords: nitrate, discharge regime, hyporheic zone, groundwater, Mediterranean, stream, Riera Major

Nitrogen concentrations in flow separated river water

2020 ◽  
Author(s):  
Jørgen Windolf ◽  
Hans Thodsen ◽  
Henrik Tornbjerg ◽  
Brian Kronvang ◽  
Peter B. Sørensen
Keyword(s):  
Coastal Waters ◽  
Stream Water ◽  
Base Flow ◽  
Rate Of Change ◽  
Data Set ◽  
Flow Component ◽  
The Past ◽  
N Concentration ◽  
N Removal ◽  
The Impact

&lt;p&gt;Nitrogen (N) loads and concentrations have been successfully reduced in most Danish streams during the last 30 years. Thereby also reducing the impact of the main driver of marine eutrophication in Danish coastal waters. However, the trend in N-loads and concentrations vary substantially among the monitored streams. The understanding of this variation are of great importance and interest for the evaluation of measures implemented to combat N eutrophication and for forecasting of effects of further measures.&lt;/p&gt;&lt;p&gt;River hydrographs can be split into base flow and quick flow components and the N concentrations in these two components can, thereafter, be calculated. The N concentration in the two components varies over time showing both longer term and seasonal variation. The quick flow component typically having a high variation reflecting present days leaching of N from fields and this strata has been significantly reduced during the last 3 decades due to a more sustainable farming practices.&lt;/p&gt;&lt;p&gt;During base flow conditions, stream water typically holds less nitrogen due to N removal in groundwater. Reductions in agricultural nitrogen leaching over the past three decades has reduced concentrations in the quick flow component and reduced the load to ground water aquifers. As groundwater aquifers are often large with a capacity of several years of recharge, the response in base flow N-concentrations is expected to be slow compared to the response in quick flow. The low response of the N-concentrations in base flow have implications on the rate of change of the river concentrations and consequently riverine N-loads to coastal waters. In some cases, the base flow N-concentration might still be influenced by the larger N-leaching of the past (1960-1990).&lt;/p&gt;&lt;p&gt;We have analyzed a national data set for developments in N-concentrations during base flow and quick flow. The data set covers the in country range in catchment size, land use and geology. The data set spans 29 years covering the period 1990 &amp;#8211; 2018. In addition, measurements from a few streams monitored for a longer period have been included in the analyses&lt;/p&gt;

Effects of riffle–step restoration on hyporheic zone chemistry in N-rich lowland streams

2006 ◽  
Vol 63 (1) ◽  
pp. 120-133 ◽  
Author(s):  
Tamao Kasahara ◽  
Alan R Hill
Keyword(s):  
Urban Areas ◽  
Hyporheic Zone ◽  
Stream Water ◽  
Ion Concentration ◽  
Hyporheic Exchange ◽  
Ecosystem Functions ◽  
Exchange Flow ◽  
Nutrient Inputs ◽  
Lowland Streams ◽  
Hyporheic Zones

Stream restoration projects that aim to rehabilitate ecosystem health have not considered surface–subsurface linkages, although stream water and groundwater interaction has an important role in sustaining stream ecosystem functions. The present study examined the effect of constructed riffles and a step on hyporheic exchange flow and chemistry in restored reaches of several N-rich agricultural and urban streams in southern Ontario. Hydrometric data collected from a network of piezometers and conservative tracer releases indicated that the constructed riffles and steps were effective in inducing hyporheic exchange. However, despite the use of cobbles and boulders in the riffle construction, high stream dissolved oxygen (DO) concentrations were depleted rapidly with depth into the hyporheic zones. Differences between observed and predicted nitrate concentrations based on conservative ion concentration patterns indicated that these hyporheic zones were also nitrate sinks. Zones of low hydraulic conductivity and the occurrence of interstitial fines in the restored cobble-boulder layers suggest that siltation and clogging of the streambed may reduce the downwelling of oxygen- and nitrate-rich stream water. Increases in streambed DO levels and enhancement of habitat for hyporheic fauna that result from riffle–step construction projects may only be temporary in streams that receive increased sediment and nutrient inputs from urban areas and croplands.

Periodic alterations of the hydrological exchange in hyporheic sediments: colmation, hyporheic fauna and abiotic parameters in a second order stream during one year 

2021 ◽  
Author(s):  
Heide Stein ◽  
Hans Jürgen Hahn
Keyword(s):  
Hyporheic Zone ◽  
Stream Water ◽  
Anthropogenic Activities ◽  
Second Order ◽  
Critical Periods ◽  
Order Stream ◽  
Fine Sediments ◽  
Stream Discharge ◽  
One Year ◽  
Hydrological Exchange

&lt;p&gt;In this study, the temporal variability of the hydrological exchange between stream water (SW) and groundwater (GW), colmation, hyporheic invertebrate fauna, organic matter (OM) and physicochemical parameters were examined for the period of one year. Sampling and measuring were conducted monthly from May 2019 to April 2020 at the Guldenbach river, a second order stream in Rhineland-Palatinate, Germany. All hyporheic samples were extracted from a depth of 15 cm below stream bottom. Colmation was measured quantitatively in the same depth.&lt;/p&gt;&lt;p&gt;Following the biotic and abiotic patterns found, three temporal stages of different hydrological conditions can be described:&lt;/p&gt;&lt;ul&gt;&lt;li&gt;1) Strong floods, in February and March 2020 caused hydromorphological alterations of the river bed, leading to a decolmation of the hyporheic zone, a wash out of OM and hyporheic fauna. Due to high GW tables the vertical hydrological gradient (VHG) was positive indicating upwelling GW.&lt;/li&gt; &lt;li&gt;2) In the months of Mai to August 2019 and April 2020, precipitation and stream discharge were lowest. Predominantly exfiltrating conditions were observed, while the amount of fine sediments (clay and silt) increased as well as colmation. High densities of hyporheic fauna, dominated by fine sediment dwelling taxa, were assessed.&lt;/li&gt; &lt;li&gt;3) From September 2019 to January 2020 stream discharge was low. The VHG became increasingly negative, indicating downwelling SW. In accordance, colmation increased continuously, while densities of hyporheic invertebrates decreased and sediment dwellers became more dominant.&lt;/li&gt; &lt;/ul&gt;&lt;p&gt;Precipitation, discharge events and GW table were found to be the driving factors for the annual dynamics of the hydrological exchange as well as for colmation, fauna and hydrochemistry. Electric conductivity seems a suitable indicator for the origin of water with high values in months of low precipitation and lower values after extensive precipitation events, respectively. Hyporheic fauna displayed a significant seasonality and the community structure was correlated with colmation and changes in the VHG.&lt;/p&gt;&lt;p&gt;This pronounced seasonality seems to be typical of many streams and should be considered for the monitoring of sediments and hyporheic habitats: Seasons with lower stream discharge are probably the most critical periods for sediment conditions.&lt;/p&gt;&lt;p&gt;We assume that the basic patterns of the dynamics observed basically reflect the natural situation in the catchment. However, the strength of surface run-off and the amount of fine sediments are mainly the result of anthropogenic activities and land use in the catchment.&lt;/p&gt;&lt;p&gt;These findings underline the significance of dynamical processes for the assessment and implementation of the Water Framework Directive.&lt;/p&gt;

scholarly journals Effect on nitrate concentration in stream water of agricultural practices in small catchments in Brittany: I. Annual nitrogen budgets

2002 ◽  
Vol 6 (3) ◽  
pp. 497-506 ◽  
Author(s):  
L. Ruiz ◽  
S. Abiven ◽  
P. Durand ◽  
C. Martin ◽  
F. Vertès ◽  
...  
Keyword(s):  
Land Use ◽  
Nitrate Concentration ◽  
Stream Water ◽  
Agricultural Practices ◽  
Climatic Conditions ◽  
Nitrogen Budgets ◽  
Annual Variations ◽  
Nitrate Concentrations ◽  
The Mean ◽  
Small Catchments

Abstract. The hydrological and biogeochemical monitoring of catchments has become a common approach for studying the effect of the evolution of agricultural practices on water resources. In numerous studies, the catchment is used as a "mega-lysimeter" to calculate annual input-output budgets. However, the literature reflects two opposite interpretations of the trends of nitrate concentration in streamwater. For some authors, essentially in applied studies, the mean residence time of leached nitrate in shallow groundwater systems is much less than one year and river loads reflect annual land use while for others, nitrate is essentially transport limited, independent of soil nitrate supply in the short term and annual variations reflect changes in climatic conditions. This study tests the effect of agricultural land-use changes on inter-annual nitrate trends on stream water of six small adjacent catchments from 0.10 to 0.57 km2 in area, on granite bedrock, at Kerbernez, in Western Brittany (France). Nitrate concentrations and loads in streamwater have been monitored for nine years (1992 to 2000) at the outlet of the catchments. An extensive survey of agricultural practices from 1993 to 1999 allowed assessment of the nitrogen available for leaching through nitrogen budgets. For such small catchments, year-to-year variations of nitrate leaching can be very important, even when considering the 'memory effect' of soil, while nitrate concentrations in streamwater appear relatively steady. No correlation was found between the calculated mean nitrate concentration of drainage water and the mean annual concentration in streams, which can even exhibit opposite trends in inter-annual variations. The climatic conditions do not affect the mean concentration in streamwater significantly. These results suggest that groundwater plays an important role in the control of streamwater nitrate concentration. Keywords: nitrate, diffuse pollution, agricultural catchment, nitrogen budget, leaching, Kerbernez catchments

scholarly journals Assessment of Hydrologic Transient Storage of Three Streams

2003 ◽  
Vol 27 ◽  
pp. 79-80
Author(s):  
Michael Gooseff
Keyword(s):  
Porous Media ◽  
Hyporheic Zone ◽  
Stream Water ◽  
Stream Sediments ◽  
Hyporheic Exchange ◽  
Ecosystem Functions ◽  
Main Stream ◽  
Stream Channel ◽  
Ample Opportunity ◽  
Biogeochemical Transformations

Stream sediments are important locations of biogeochemical transformations upon which many stream ecosystem functions depend. Stream water is often exchanged between the stream channel and surrounding subsurface locations - this process is known as hyporheic exchange. While stream water is moving through the hyporheic zone, solutes and nutrients may undergo important chemical reactions that are not possible in the main stream channel. Further, because the hyporheic zone is composed of porous media (sand, sediment, alluvium, etc.), flow inherently slows down and the exchanging water has ample opportunity to interact with mineral grain surfaces and biofilms.

scholarly journals Managing pollutant inputs from pastoral dairy farming to maintain water quality of a lake in a high-rainfall catchment

2013 ◽  
Vol 64 (5) ◽  
pp. 447 ◽  
Author(s):  
Robert J. Wilcock ◽  
Ross M. Monaghan ◽  
Richard W. McDowell ◽  
Piet Verburg ◽  
Jonny Horrox ◽  
...  
Keyword(s):  
Stream Water ◽  
Most Probable Number ◽  
Deep Drainage ◽  
Probable Number ◽  
E Coli ◽  
High Rainfall ◽  
Flow Monitoring ◽  
Storm Flow ◽  
Outlet Flow

A study (2004–11) of a dairy catchment stream entering an oligotrophic lake in an area of very high rainfall (~5 m year–1) yielded median concentrations of total nitrogen (TN), total phosphorus (TP), suspended sediment (SS) and Escherichia coli (E. coli) of 0.584, 0.074 and 3.7 g m–3, and 405/100 mL (most probable number method), respectively. Trend analysis indicated significant (P < 0.01) decreases for TN (–0.08 ± 0.02 g m–3 year–1), TP (–0.01 ± 0.005 g m–3 year–1) and SS (–0.45 ± 0.14 g m–3 year–1) and were partly attributable to improved exclusion of cattle from the stream. Water balance calculations indicated that approximately one-half the rainfall left as deep drainage that by-passed catchment outlet flow recorders. Estimates of catchment yields for TN were improved by taking into account groundwater hydrology and concentrations from well samples. Storm-flow monitoring inflows exceeding the 97.5th percentile contributed ~40% of total loads leaving the catchment so that specific yields for SS, TN and TP augmented by groundwater inputs and storm flows were ~960, 45 and 7 kg ha–1 year–1, respectively. These compared well with modelled results for losses from dairy farms in the catchment of 40–60 kg N ha–1 year–1 and 5–6 kg P ha–1 year–1 and indicated that attenuation losses were relatively small.

scholarly journals Integrated Nitrogen CAtchment model (INCA) applied to a tropical catchment in the Atlantic Forest, São Paulo, Brazil

2007 ◽  
Vol 11 (1) ◽  
pp. 614-622 ◽  
Author(s):  
M. Ranzini ◽  
M. C. Forti ◽  
P. G. Whitehead ◽  
F. C. S. Arcova ◽  
V. de Cicco ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
Atlantic Forest ◽  
Stream Water ◽  
N Deposition ◽  
Sao Paulo ◽  
N Leaching ◽  
São Paulo ◽  
Intensive Farming ◽  
N Concentration ◽  
Se Brazil

Abstract. Stream-water flows and in-stream nitrate and ammonium concentrations in a small (36.7 ha) Atlantic Forest catchment were simulated using the Integrated Nitrogen in CAtchments (INCA) model version 1.9.4. The catchment, at Cunha, is in the Serra do Mar State Park, SE Brazil and is nearly pristine because the nearest major conurbations, São Paulo and Rio, are some 450 km distant. However, intensive farming may increase nitrogen (N) deposition and there are growing pressures for urbanisation. The mean-monthly discharges and NO3-N concentration dynamics were simulated adequately for the calibration and validation periods with (simulated) loss rates of 6.55 kg.ha−1 yr−1 for NO3-N and 3.85 kg.ha−1 yr−1 for NH4-N. To investigate the effects of elevated levels of N deposition in the future, various scenarios for atmospheric deposition were simulated; the highest value corresponded to that in a highly polluted area of Atlantic Forest in Sao Paulo City. It was found that doubling the atmospheric deposition generated a 25% increase in the N leaching rate, while at levels approaching the highly polluted São Paulo deposition rate, five times higher than the current rate, leaching increased by 240%, which would create highly eutrophic conditions, detrimental to downstream water quality. The results indicate that the INCA model can be useful for estimating N concentration and fluxes for different atmospheric deposition rates and hydrological conditions.

scholarly journals The influence of riparian-hyporheic zone on the hydrological responses in an intermittent stream

2002 ◽  
Vol 6 (3) ◽  
pp. 515-526 ◽  
Author(s):  
A. Butturini ◽  
S. Bernal ◽  
S. Sabater ◽  
F. Sabater
Keyword(s):  
Groundwater Level ◽  
Mediterranean Climate ◽  
Hyporheic Zone ◽  
Stream Water ◽  
Wide Spectrum ◽  
Groundwater Hydrology ◽  
Dry Period ◽  
Intermittent Stream ◽  
Hydrological Responses ◽  
Runoff Variability

Abstract. Stream and riparian groundwater hydrology has been studied in a small intermittent stream draining a forested catchment for a system representative of a Mediterranean climate. The relationship between precipitation and stream runoff and the interactions between stream water and the surrounding riparian groundwater have been analysed under a wide spectrum of meteorological conditions. The hypothesis that the hydrological condition of the near-stream groundwater compartment can regulate the runoff generation during precipitation events was tested. Stream runoff is characterised by a summer dry period, and precipitation input explained only 25% of runoff variability over the study period (r2 =0.25, d.f.=51, p<0.001). The variability of precipitation v. stream runoff is explained partly by the hydrogeological properties of the riparian near-stream zone. This zone is characterised by high hydrological conductivity values and abrupt changes in groundwater level in summer. The summer dry period begins with a rapid decrease in near-stream groundwater level, and ends just after the first autumnal rain when the original groundwater level recovers suddenly. Within this period, storms do not cause major stream runoff since water infiltrates rapidly into the riparian compartment until it is refilled during the subsequent winter and spring; then the precipitation explains the 80% of the stream runoff variability (r2=0.80, d.f.=34, p<0.001). These results suggest that the hydrological interaction between the riparian groundwater compartment and the stream channel is important in elucidating the hydrological responses during drought periods in small Mediterranean streams. Keywords: riparian zone, groundwater hydrology, runoff, intermittent stream, Mediterranean climate

scholarly journals Widespread detection of human- and ruminant-origin Bacteroidales markers in subtidal waters of the Salish Sea in Washington State

2015 ◽  
Vol 13 (3) ◽  
pp. 827-837 ◽  
Author(s):  
Zack S. Oyafuso ◽  
Anne E. Baxter ◽  
Jason E. Hall ◽  
Sean M. Naman ◽  
Correigh M. Greene ◽  
...  
Keyword(s):  
Transport Mechanism ◽  
Nitrate Concentration ◽  
Impervious Surface ◽  
Washington State ◽  
Marine Water ◽  
Ammonium Concentration ◽  
Mean Flow ◽  
Salish Sea ◽  
Coastal Systems ◽  
Marker Detection

Rising populations around coastal systems are increasing the threats to marine water quality. To assess anthropogenic fecal influence, subtidal waters were examined monthly for human- and ruminant-sourced Bacteroidales markers at 80 sites across six oceanographic basins of the Salish Sea (Washington State) from April through October, 2011. In the basins containing cities with individual populations &gt;190,000, &gt;50% of sites were positive for the human marker, while in the basins with high densities of dairy and cattle operations, ∼30% of sites were positive for the ruminant marker. Marker prevalence was elevated in spring (April and May) and fall (October) and reduced during summer (June through September), corresponding with seasonal precipitation. By logistic regression, the odds of human marker detection increased with percentage of adjacent catchment impervious surface, dissolved nitrate concentration, and abundance of low nucleic acid bacteria, but decreased with salinity and chlorophyll fluorescence. The odds of ruminant marker detection increased with dissolved ammonium concentration, mean flow rate for the nearest river, and adjacent shoreline length. These relationships are consistent with terrestrial to marine water flow as a transport mechanism. Thus, Bacteroidales markers traditionally used for identifying nearby sources can be used for assessing anthropogenic fecal inputs to regional marine ecosystems.

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