Comparison of the event and seasonal hillslope-stream hydrologic connectivity in an agricultural headwater catchment

<p>In agricultural catchments, subsurface runoff is an important process for streamflow generation and the transport of nutrients and pollutants within and out of the catchment. Where and when subsurface runoff occurs is linked to the hydrologic connectivity in the catchment. This study compares spatial patterns of the connectivity between the hillslope and the stream on the event and seasonal scale. We analyse streamflow and groundwater responses to 53 precipitation events and their seasonal dynamics over two years in the Hydrologic Open Air Laboratory (HOAL), a small (66 ha) agricultural headwater catchment in Lower Austria. We quantify the connectivity in terms of Spearman correlation, hysteresis index and peak-to-peak time between streamflow and groundwater dynamics. It shows a clear spatial pattern, i.e. the connectivity is greatest in the riparian zone and diminishes further away from the stream where the groundwater table is deeper. This is reflected in the significant correlation of connectivity to the topographic indices and groundwater depth. Groundwater connectivity to the stream on the seasonal scale is higher than that on the event scale, indicating that groundwater contributes more to the baseflow than event runoff.</p>

Download Full-text

High-frequency measurements explain quantity and quality of dissolved organic carbon mobilization in a headwater catchment

Biogeosciences ◽

10.5194/bg-16-4497-2019 ◽

2019 ◽

Vol 16 (22) ◽

pp. 4497-4516 ◽

Cited By ~ 1

Author(s):

Benedikt J. Werner ◽

Andreas Musolff ◽

Oliver J. Lechtenfeld ◽

Gerrit H. de Rooij ◽

Marieke R. Oosterwoud ◽

...

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

High Frequency ◽

Riparian Zone ◽

Quality Parameters ◽

Riparian Zones ◽

Frequency Measurements ◽

Seasonal Scale ◽

Headwater Catchment

Abstract. Increasing dissolved organic carbon (DOC) concentrations and exports from headwater catchments impact the quality of downstream waters and pose challenges to water supply. The importance of riparian zones for DOC export from catchments in humid, temperate climates has generally been acknowledged, but the hydrological controls and biogeochemical factors that govern mobilization of DOC from riparian zones remain elusive. A high-frequency dataset (15 min resolution for over 1 year) from a headwater catchment in the Harz Mountains (Germany) was analyzed for dominant patterns in DOC concentration (CDOC) and optical DOC quality parameters SUVA254 and S275−295 (spectral slope between 275 and 295 nm) on event and seasonal scales. Quality parameters and CDOC systematically changed with increasing fractions of high-frequency quick flow (Qhf) and antecedent hydroclimatic conditions, defined by the following metrics: aridity index (AI60) of the preceding 60 d and the quotient of mean temperature (T30) and mean discharge (Q30) of the preceding 30 d, which we refer to as discharge-normalized temperature (DNT30). Selected statistical multiple linear regression models for the complete time series (R2=0.72, 0.64 and 0.65 for CDOC, SUVA254 and S275−295, resp.) captured DOC dynamics based on event (Qhf and baseflow) and seasonal-scale predictors (AI60, DNT30). The relative importance of seasonal-scale predictors allowed for the separation of three hydroclimatic states (warm and dry, cold and wet, and intermediate). The specific DOC quality for each state indicates a shift in the activated source zones and highlights the importance of antecedent conditions and their impact on DOC accumulation and mobilization in the riparian zone. The warm and dry state results in high DOC concentrations during events and low concentrations between events and thus can be seen as mobilization limited, whereas the cold and wet state results in low concentration between and during events due to limited DOC accumulation in the riparian zone. The study demonstrates the considerable value of continuous high-frequency measurements of DOC quality and quantity and its (hydroclimatic) key controlling variables in quantitatively unraveling DOC mobilization in the riparian zone. These variables can be linked to DOC source activation by discharge events and the more seasonal control of DOC production in riparian soils.

Download Full-text

Event and seasonal hydrologic connectivity patterns in an agricultural headwater catchment

Hydrology and Earth System Sciences ◽

10.5194/hess-25-2327-2021 ◽

2021 ◽

Vol 25 (4) ◽

pp. 2327-2352

Author(s):

Lovrenc Pavlin ◽

Borbála Széles ◽

Peter Strauss ◽

Alfred Paul Blaschke ◽

Günter Blöschl

Keyword(s):

Soil Moisture ◽

Spatial Organization ◽

Groundwater Table ◽

Peak Time ◽

Spatial And Temporal Patterns ◽

Topographic Wetness Index ◽

Event Scale ◽

Soil Moisture Dynamics ◽

Moisture Dynamics ◽

Headwater Catchment

Abstract. Connectivity of the hillslope and the stream is a non-stationary and non-linear phenomenon dependent on many controls. The objective of this study is to identify these controls by examining the spatial and temporal patterns of the similarity between shallow groundwater and soil moisture dynamics and streamflow dynamics in the Hydrological Open Air Laboratory (HOAL), a small (66 ha) agricultural headwater catchment in Lower Austria. We investigate the responses to 53 precipitation events and the seasonal dynamics of streamflow, groundwater and soil moisture over 2 years. The similarity, in terms of Spearman correlation coefficient, hysteresis index and peak-to-peak time, of groundwater to streamflow shows a clear spatial organization, which is best correlated with topographic position index, topographic wetness index and depth to the groundwater table. The similarity is greatest in the riparian zone and diminishes further away from the stream where the groundwater table is deeper. Soil moisture dynamics show high similarity to streamflow but no clear spatial pattern. This is reflected in a low correlation of the similarity with site characteristics. However, the similarity increases with increasing catchment wetness and rainfall duration. Groundwater connectivity to the stream on the seasonal scale is higher than that on the event scale, indicating that groundwater contributes more to the baseflow than to event runoff.

Download Full-text

Event and seasonal hydrologic connectivity patterns in an agricultural headwater catchment

10.5194/hess-2020-372 ◽

2020 ◽

Author(s):

Lovrenc Pavlin ◽

Borbála Széles ◽

Peter Strauss ◽

Alfred Paul Blaschke ◽

Günter Blöschl

Keyword(s):

Soil Moisture ◽

Shallow Groundwater ◽

Groundwater Table ◽

Peak Time ◽

Spatial And Temporal Patterns ◽

Topographic Wetness Index ◽

Event Scale ◽

Soil Moisture Dynamics ◽

Moisture Dynamics ◽

Headwater Catchment

Abstract. Connectivity of the hillslope and the stream is a non stationary and non linear phenomenon dependent on many controls. The objective of this study is to identify these controls by examining the spatial and temporal patterns of the similarity between shallow groundwater and soil moisture dynamics and streamflow dynamics in the Hydrological Open Air Laboratory (HOAL), a small (66 ha) agricultural headwater catchment in Lower Austria. We investigate the responses to 53 precipitation events and the seasonal dynamics of streamflow, groundwater and soil moisture over two years. The similarity, in terms of Spearman correlation coefficient, hysteresis index and peak-to-peak time, of groundwater to streamflow shows a clear spatial organisation, which is best correlated to topographic position index, topographic wetness index and depth to the groundwater table. The similarity is greatest in the riparian zone and diminishes further away from the stream where the groundwater table is deeper. Soil moisture dynamics show high similarity to streamflow but no clear spatial pattern. This is reflected in a low correlation of the similarity to site-characteristics, however, the similarity increases with increasing catchment wetness and rainfall duration. Groundwater connectivity to the stream on the seasonal scale is higher than that on the event scale indicating that groundwater contributes more to the baseflow than to event runoff.

Download Full-text

High-frequency measurements of dissolved organic carbon quantity and quality in a headwater catchment

10.5194/bg-2019-188 ◽

2019 ◽

Author(s):

Benedikt J. Werner ◽

Andreas Musolff ◽

Oliver J. Lechtenfeld ◽

Gerrit H. de Rooij ◽

Marieke R. Oosterwoud ◽

...

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

High Frequency ◽

Riparian Zone ◽

Aridity Index ◽

Quality Parameters ◽

Riparian Zones ◽

Statistical Regression ◽

Seasonal Scale ◽

Headwater Catchment

Abstract. Increasing dissolved organic carbon (DOC) exports from headwater catchments impact the quality of downstream waters and pose challenges to water supply. The importance of riparian zones for DOC export from catchments in humid, temperate climates has generally been acknowledged, but the hydrological controls and biogeochemical factors that govern mobilization of DOC from riparian zones remain elusive. A one-year high-frequency (15 minutes) dataset from a headwater catchment in the Harz Mountains (Germany) was analyzed for dominant patterns in DOC concentration (CDOC) and optical DOC quality parameters SUVA254 and S275-295 (spectral slope between 275 nm and 295 nm) on event and seasonal scale. Quality parameters and CDOC systematically changed with increasing fractions of high-frequency quick flow (Qhf) and antecedent hydroclimatic conditions, defined by the following metrics: Aridity Index (AI60) of the preceding 60 days, mean temperature (T30) and discharge (Q30) of the preceding 30 days and the quotient T30/Q30 which we refer to as discharge-normalized temperature (DNT30). Selected statistical regression models for the complete time series (R² = 0.72, 0.64 and 0.65 for CDOC, SUVA254 and S275-295, resp.) captured DOC dynamics based on event (Qhf and baseflow) and seasonal-scale predictors (AI60, DNT30). The relative importance of seasonal-scale predictors allowed for the separation of three hydroclimatic states (warm & dry, cold & wet and intermediate). The specific DOC quality for each state indicates a shift in the activated source zones and highlights the importance of antecedent conditions and its impact on DOC accumulation and mobilization in the riparian zone. The warm & dry state results in high DOC concentrations during events and low concentrations between events and thus can be seen as mobilization limited, whereas the cold & wet state results in low concentration between and during events due to limited DOC accumulation in the riparian zone. We conclude that the high concentration variability of DOC in the stream can be explained by only a few controlling variables. These variables can be linked to DOC source activation by discharge events and the more seasonal control of DOC production in riparian soils.

Download Full-text

Colloidal catchment response to snowmelt and precipitation events differs in a forested headwater catchment

Vadose Zone Journal ◽

10.1002/vzj2.20126 ◽

2021 ◽

Author(s):

Dymphie J. Burger ◽

Johnny Vogel ◽

Annemieke M. Kooijman ◽

Roland Bol ◽

Eva de Rijke ◽

...

Keyword(s):

Precipitation Events ◽

Headwater Catchment

Download Full-text

Riparian zone flowpath dynamics during snowmelt in a small headwater catchment

Journal of Hydrology ◽

10.1016/s0022-1694(99)00102-x ◽

1999 ◽

Vol 222 (1-4) ◽

pp. 75-92 ◽

Cited By ~ 109

Author(s):

B.L McGlynn ◽

J.J McDonnell ◽

J.B Shanley ◽

C Kendall

Keyword(s):

Riparian Zone ◽

Headwater Catchment

Download Full-text

THE ROLE OF SUBSURFACE FLOW DYNAMIC ON SPATIAL AND TEMPORAL VARIATION OF WATER CHEMISTRY IN A HEADWATER CATCHMENT

Indonesian Journal of Agricultural Science ◽

10.21082/ijas.v8n1.2007.p17-30 ◽

2016 ◽

Vol 8 (1) ◽

pp. 17

Author(s):

Tadashi Tanaka

Keyword(s):

Water Chemistry ◽

Temporal Variation ◽

Random Process ◽

Riparian Zone ◽

Subsurface Flow ◽

Solute Concentration ◽

Spatial And Temporal Variation ◽

Flow Dynamic ◽

Headwater Catchment

Variation of water chemistry does not merely occur due to in situ chemical process, but also transport process. The study was carried out to address the role of subsurface flow dynamic on spatial and temporal variation of water chemistry in a headwater catchment. Hydrometric and hydrochemistry measurements were done in transect with nested piezometers, tensiometers, and suction samplers at different depths across hillslope and riparian zone in a 5.2 ha first-order drainage of the Kawakami experimental basin, Nagano, Central Japan from August 2000 to August 2001. Spatial variation of solute concentration was defined by the standard deviation and coefficient of variation of the seasonal observed concentrations. Autocorrelation analysis was performed to define temporal variation of solute concentration. The results showed that spatial variation of water chemistry was mainly influenced by the variation of subsurface flow through the hillslope and riparian zone. Solute concentration in the deep riparian groundwater was almost three times higher than that in the hillslope segment. A prominent downward flow in deep riparian groundwater zone provided transport of solutes to the deeper layer. Time series analysis showed that in the deep riparian groundwater, Ca2+, Mg2+, SO42- and HCO3- concentrations underwent a random process, Na+ concentration of a random process superimposed by a trend process, and SiO2 of a random process superimposed by a periodic process. Near the riparian surface, SO42- concentration was composed of a random process superimposed by a periodic process, whereas other solutes were mainly in a random process. In the hillslope soil water, there was no trend observed for the Na+ concentration, but there were for Ca2+ and Mg2+. The magnitude and direction of subsurface flow across hillslope and riparian zone created transport and deposition processes that changed solute concentration spatially and temporally.

Download Full-text

The influence of soil moisture on threshold runoff generation processes in an alpine headwater catchment

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-7-8091-2010 ◽

2010 ◽

Vol 7 (5) ◽

pp. 8091-8124 ◽

Cited By ~ 1

Author(s):

D. Penna ◽

H. J. Tromp-van Meerveld ◽

A. Gobbi ◽

M. Borga ◽

G. Dalla Fontana

Keyword(s):

Soil Moisture ◽

Overland Flow ◽

Riparian Zone ◽

Temporal Dynamics ◽

Runoff Generation ◽

Antecedent Conditions ◽

Antecedent Moisture ◽

Dry Conditions ◽

Strong Control ◽

Headwater Catchment

Abstract. This study investigates the role of soil moisture on the threshold runoff response in a small headwater catchment in the Italian Alps that is characterised by steep hillslopes and a distinct riparian zone. This study focuses on: (i) the threshold soil moisture-runoff relationship and the influence of catchment topography on this relation; (ii) the temporal dynamics of soil moisture, streamflow and groundwater that characterize the catchment's response to rainfall during dry and wet periods; and (iii) the combined effect of antecedent wetness conditions and rainfall amount on hillslope and riparian runoff. Our results highlight the strong control exerted by soil moisture on runoff in this catchment: a sharp threshold exists in the relationship between soil water content and runoff coefficient, streamflow, and hillslope-averaged depth to water table. Low runoff ratios were related to the response of the riparian zone, which was always close to saturation. High runoff ratios occurred during wet antecedent conditions, when the soil moisture threshold was exceeded. In these cases, subsurface flow was activated on hillslopes, which became major contributors to runoff. Antecedent wetness conditions also controlled the catchment's response time: during dry periods, streamflow reacted and peaked prior to hillslope soil moisture whereas during wet conditions the opposite occurred. This difference resulted in a hysteretic behaviour in the soil moisture-streamflow relationship. Finally, the influence of antecedent moisture conditions on runoff was also evident in the relation between cumulative rainfall and total stormflow. Small storms during dry conditions produced low runoff amounts, mainly from overland flow from the near saturated riparian zone. Conversely, for rainfall events during wet conditions, hillslopes contributed to streamflow and higher runoff values were observed.

Download Full-text