Lag Times as Indicators of Hydrological Mechanisms Responsible for NO<sub>3</sub>-N Flushing in a Forested Headwater Catchment
Understanding the temporal variability of the nutrient transport from catchments is essential for planning nutrient loss reduction measures related to land use and climate change. Moreover, observations and analysis of nutrient dynamics in streams draining undisturbed catchments are known to represe...
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| Format: | Article |
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MDPI AG
2020-04-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/12/4/1092 |
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| author | Klaudija Sapač Andrej Vidmar Nejc Bezak Simon Rusjan |
| author_facet | Klaudija Sapač Andrej Vidmar Nejc Bezak Simon Rusjan |
| author_sort | Klaudija Sapač |
| collection | DOAJ |
| description | Understanding the temporal variability of the nutrient transport from catchments is essential for planning nutrient loss reduction measures related to land use and climate change. Moreover, observations and analysis of nutrient dynamics in streams draining undisturbed catchments are known to represent a reference point by which human-influenced catchments can be compared. In this paper, temporal dynamics of nitrate-nitrogen (NO<sub>3</sub>-N) flux are investigated on an event basis by analysing observed lag times between data series. More specifically, we studied lag times between the centres of mass of six hydrological and biogeochemical variables, namely discharge, soil moisture at three depths, NO<sub>3</sub>-N flux, and the precipitation hyetograph centre of mass. Data obtained by high-frequency measurements (20 min time step) from 29 events were analysed. Linear regression and multiple linear regression (MLR) were used to identify relationships between lag times of the above-mentioned processes. We found that discharge lag time (LAG<sub>Q</sub>) and NO<sub>3</sub>-N flux lag time (LAG<sub>N</sub>) are highly correlated indicating similar temporal response to rainfall. Moreover, relatively high correlation between LAG<sub>N</sub> and soil moisture lag times was also detected. The MLR model showed that the most descriptive variable for both LAG<sub>N</sub> and LAG<sub>Q</sub> is amount of precipitation. For LAG<sub>N</sub>, the change of the soil moisture in the upper two layers was also significant, suggesting that the lag times indicate the primarily role of the forest soils as the main source of the NO<sub>3</sub>-N flux, whereas the precipitation amount and the runoff formation through the forest soils are the main controlling mechanisms. |
| first_indexed | 2024-03-10T20:31:21Z |
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| id | doaj.art-c69acfba668143d5aa31e152878e0f48 |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-10T20:31:21Z |
| publishDate | 2020-04-01 |
| publisher | MDPI AG |
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| series | Water |
| spelling | doaj.art-c69acfba668143d5aa31e152878e0f482023-11-19T21:23:38ZengMDPI AGWater2073-44412020-04-01124109210.3390/w12041092Lag Times as Indicators of Hydrological Mechanisms Responsible for NO<sub>3</sub>-N Flushing in a Forested Headwater CatchmentKlaudija Sapač0Andrej Vidmar1Nejc Bezak2Simon Rusjan3Faculty of Civil and Geodetic Engineering, University of Ljubljana, Jamova 2, 1000 Ljubljana, SloveniaFaculty of Civil and Geodetic Engineering, University of Ljubljana, Jamova 2, 1000 Ljubljana, SloveniaFaculty of Civil and Geodetic Engineering, University of Ljubljana, Jamova 2, 1000 Ljubljana, SloveniaFaculty of Civil and Geodetic Engineering, University of Ljubljana, Jamova 2, 1000 Ljubljana, SloveniaUnderstanding the temporal variability of the nutrient transport from catchments is essential for planning nutrient loss reduction measures related to land use and climate change. Moreover, observations and analysis of nutrient dynamics in streams draining undisturbed catchments are known to represent a reference point by which human-influenced catchments can be compared. In this paper, temporal dynamics of nitrate-nitrogen (NO<sub>3</sub>-N) flux are investigated on an event basis by analysing observed lag times between data series. More specifically, we studied lag times between the centres of mass of six hydrological and biogeochemical variables, namely discharge, soil moisture at three depths, NO<sub>3</sub>-N flux, and the precipitation hyetograph centre of mass. Data obtained by high-frequency measurements (20 min time step) from 29 events were analysed. Linear regression and multiple linear regression (MLR) were used to identify relationships between lag times of the above-mentioned processes. We found that discharge lag time (LAG<sub>Q</sub>) and NO<sub>3</sub>-N flux lag time (LAG<sub>N</sub>) are highly correlated indicating similar temporal response to rainfall. Moreover, relatively high correlation between LAG<sub>N</sub> and soil moisture lag times was also detected. The MLR model showed that the most descriptive variable for both LAG<sub>N</sub> and LAG<sub>Q</sub> is amount of precipitation. For LAG<sub>N</sub>, the change of the soil moisture in the upper two layers was also significant, suggesting that the lag times indicate the primarily role of the forest soils as the main source of the NO<sub>3</sub>-N flux, whereas the precipitation amount and the runoff formation through the forest soils are the main controlling mechanisms.https://www.mdpi.com/2073-4441/12/4/1092hydrological processessoil moistureprecipitationrunoffnitrate fluxforested catchment |
| spellingShingle | Klaudija Sapač Andrej Vidmar Nejc Bezak Simon Rusjan Lag Times as Indicators of Hydrological Mechanisms Responsible for NO<sub>3</sub>-N Flushing in a Forested Headwater Catchment Water hydrological processes soil moisture precipitation runoff nitrate flux forested catchment |
| title | Lag Times as Indicators of Hydrological Mechanisms Responsible for NO<sub>3</sub>-N Flushing in a Forested Headwater Catchment |
| title_full | Lag Times as Indicators of Hydrological Mechanisms Responsible for NO<sub>3</sub>-N Flushing in a Forested Headwater Catchment |
| title_fullStr | Lag Times as Indicators of Hydrological Mechanisms Responsible for NO<sub>3</sub>-N Flushing in a Forested Headwater Catchment |
| title_full_unstemmed | Lag Times as Indicators of Hydrological Mechanisms Responsible for NO<sub>3</sub>-N Flushing in a Forested Headwater Catchment |
| title_short | Lag Times as Indicators of Hydrological Mechanisms Responsible for NO<sub>3</sub>-N Flushing in a Forested Headwater Catchment |
| title_sort | lag times as indicators of hydrological mechanisms responsible for no sub 3 sub n flushing in a forested headwater catchment |
| topic | hydrological processes soil moisture precipitation runoff nitrate flux forested catchment |
| url | https://www.mdpi.com/2073-4441/12/4/1092 |
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