scholarly journals Differences in Stream Water Nitrate Concentrations between a Nitrogen-Saturated Upland Forest and a Downstream Mixed Land Use River Basin

Hydrology ◽  
2017 ◽  
Vol 4 (3) ◽  
pp. 43 ◽  
Author(s):  
Ken’ichi Shinozuka ◽  
Masaaki Chiwa ◽  
Ichiro Tayasu ◽  
Chikage Yoshimizu ◽  
Kyoichi Otsuki ◽  
...  
2002 ◽  
Vol 6 (3) ◽  
pp. 497-506 ◽  
Author(s):  
L. Ruiz ◽  
S. Abiven ◽  
P. Durand ◽  
C. Martin ◽  
F. Vertès ◽  
...  

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


2019 ◽  
Vol 35 (3) ◽  
pp. 259-267 ◽  
Author(s):  
Evan M. Chua ◽  
Scott P. Wilson ◽  
Sue Vink ◽  
Nicole Flint

2002 ◽  
Vol 6 (3) ◽  
pp. 507-514 ◽  
Author(s):  
L. Ruiz ◽  
S. Abiven ◽  
C. Martin ◽  
P. Durand ◽  
V. Beaujouan ◽  
...  

Abstract. In catchments with impervious bedrock, the nitrate concentrations in streamwater often show marked seasonal and small inter-annual variations. The inter-annual trends are usually attributed to changes in nitrogen inputs, due to changes in land use or in nitrogen deposition whereas seasonal patterns are explained in terms of availability of soil nitrate for leaching and of seasonality of nitrogen biotransformations. The companion paper showed that inter-annual variations of nitrogen in streamwater are not directly related to the variations of land use. The aim of this study is to describe nitrate concentration variations in a set of very small adjacent catchments, and to discuss the origin of the inter-annual and seasonal trends. Data from four catchments at the Kerbernez site (South Western Brittany, France) were used in this study. Nitrate concentrations in streamwater were monitored for eight years (1992 to 1999) at the outlet of the catchments. They exhibit contrasting inter-annual and seasonal patterns. An extensive survey of agricultural practices during this period allowed assessment of the amount of nitrogen available for leaching. The discharges measured since 1997 show similar specific fluxes but very different seasonal dynamics between the catchments. A simple, lumped linear store model is proposed as an initial explanation of the differences in discharge and nitrate concentration patterns between the catchments. The base flow at the outlet of each catchment is considered as a mixture of water from two linear reservoirs with different time constants. Each reservoir comprises two water stores, one mobile contributing to discharge, the other, immobile, where nitrate moves only by diffusion. The storm flow, which accounts for less than 10% of the annual flux, is not considered here. Six parameters were adjusted for each catchment to fit the observed data: the proportion of deep losses of water, the proportion of the two reservoirs and the size and initial concentration of the two immobile stores. The model simulates the discharge and nitrate concentration dynamics well. It suggests that the groundwater store plays a very important role in the control of nitrate concentration in streamwater, and that the pattern of the seasonal variation of nitrate concentration may result from the long term evolution of nitrogen losses by leaching. Keywords: nitrate, diffuse pollution, groundwater, seasonal variations, agricultural catchment, simulation model


Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 532 ◽  
Author(s):  
Fritz Petersen ◽  
Jason A. Hubbart

The relationships between Escherichia (E) coli concentration, suspended particulate matter (SPM) particle size class, and land use practices are important in reducing the bacterium’s persistence and health risks. However, surprisingly few studies have been performed that quantify these relationships. Conceivably, such information would advance mitigation strategies for practices that address specific SPM size classes and, by proxy, E. coli concentration. To advance this needed area of research, stream water was sampled from varying dominant land use practices in West Run Watershed, a representative mixed-land use Appalachian watershed of West Virginia in the eastern USA. Water samples were filtered into three SPM intervals (<5 µm; 5 µm to 60 μm; and >60 μm) and the E. coli concentration (colony forming units, CFU) and SPM of each interval was quantified. Statistically significant relationships were identified between E. coli concentrations and size intervals (α < 0.0001), and SPM (α = 0.05). The results show a predominance (90% of total) of E. coli CFUs in the <5 μm SPM interval. The results show that land use practices impact the relationships between SPM and E. coli concentrations. Future work should include additional combined factors that influence bacterial CFUs and SPM, including hydrology, climate, geochemistry and nutrients.


2010 ◽  
Vol 44 (14) ◽  
pp. 4143-4157 ◽  
Author(s):  
Joo-Hyon Kang ◽  
Seung Won Lee ◽  
Kyung Hwa Cho ◽  
Seo Jin Ki ◽  
Sung Min Cha ◽  
...  

2008 ◽  
Vol 3 (No. 3) ◽  
pp. 98-112 ◽  
Author(s):  
P. Fučík ◽  
T. Kvítek ◽  
M. Lexa ◽  
P. Novák ◽  
A. Bílková

The ecological status of many surface waters in the Czech Republic is poor, mainly due to still relatively high discharges of N substances especially from agriculture. High nitrate values in the streams situated particulary in basins of drinking water reservoirs invoke the neccesity for the precise detection of diffuse pollution areas to enable the setting of the appropriate land management strategies or relevant measures. We introduce a simple method for estimating the changes of nitrate concentrations in surface waters regarding the land use modification. Stream and drainage water nitrate concentrations in prevailingly agricultural catchments of three different scales located in the Crystalline complex of the Czech massif were included in this study. Water quality samples were collected through the years 1992&ndash;2006 at monthly and bi-monthly intervals. For the catchment land use analysis, the satellite images LANDSAT 7 (CORINE Land Cover) and digitised cadastre maps of the land register were processed using ESRI ArcMap GIS; both sources corrected by field survey. We demonstrate on three different basin &ndash; scale studies a strong relation between the arable land ratio within a catchment and the coherent stream water nitrate concentration. The results acquired from all the evaluated catchments showed that every 10% decrease of ploughed land proportion in a catchment lowers the nitrate concentration C90 value (90% probability of non-exceedance) in average by 6.38 mg/l.


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