scholarly journals Technical Note: Monitoring streamflow generation processes at Cape Fear

2016 ◽  
Author(s):  
Flavia Tauro ◽  
Andrea Petroselli ◽  
Aldo Fiori ◽  
Nunzio Romano ◽  
Maria Cristina Rulli ◽  
...  
Keyword(s):  
Overland Flow ◽  
Measurement Techniques ◽  
Technical Note ◽  
Hydrological Response ◽  
Runoff Generation ◽  
Natural Systems ◽  
Natural Rainfall ◽  
Streamflow Generation ◽  
Cape Fear ◽  
Hillslope Processes

Abstract. Hillslope processes are fundamental for the comprehension of the hydrological response of natural systems. However, their complexity demands real time and continuous observations. In this paper, we assess the feasibility of studying streamflow generation processes at Cape Fear, a "hybrid" hillslope plot at University of Tuscia, Viterbo, Italy. Cape Fear is a 7 × 7 m2 confined soil-filled wood-sided plot, whose water fluxes can be continuously monitored. The plot design is simple, yet versatile to test hypotheses on the hydrological response of hillslope areas. The suitability of the plot for investigating runoff generation and hillslope processes is presented through a demonstrative experiment in the case of a natural rainfall event. A combination of traditional and innovative measurement techniques confirms that runoff onset is due to saturation overland flow. Future studies will address the influence of diverse land covers and spatial pathways evolution on the response at the hillslope scale.

scholarly journals The dominant runoff processes on grassland versus bare soil hillslopes in a temperate environment - An experimental study

2019 ◽  
Vol 67 (4) ◽  
pp. 297-304 ◽  
Author(s):  
Gabriel Minea ◽  
Gabriela Ioana-Toroimac ◽  
Gabriela Moroşanu
Keyword(s):  
Overland Flow ◽  
Bare Soil ◽  
Rainfall Runoff ◽  
Runoff Generation ◽  
Rainfall Events ◽  
Natural Rainfall ◽  
Antecedent Precipitation ◽  
Temperate Environment ◽  
The Relationship

Abstract This paper aimed to investigate the dominant runoff processes (DRP’s) at plot-scale in the Curvature Subcarpathians under natural rainfall conditions characteristic for Romania’s temperate environment. The study was based on 32 selected rainfall-runoff events produced during the interval April–September (2014–2017). By comparing water balance on the analyzed Luvisol plots for two types of land use (grassland vs. bare soil), we showed that DRP’s are mostly formed by Hortonian Overland Flow (HOF), 47% vs. 59% respectively. On grassland, HOF is followed by Deep Percolation (DP, 31%) and Fast Subsurface Flow (SSF, 22%), whereas, on bare soil, DP shows a higher percentage (38%) and SSF a lower one (3%), which suggests that the soil-root interface controls the runoff generation. Concerning the relationship between antecedent precipitation and runoff, the study indicated the nonlinearity of the two processes, more obvious on grassland and in drought conditions than on bare soil and in wet conditions (as demonstrated by the higher runoff coefficients). Moreover, the HOF appeared to respond differently to rainfall events on the two plots - slightly longer lag-time, lower discharge and lower volume on grassland - which suggests the hydrologic key role of vegetation in runoff generation processes.

scholarly journals Connecting hillslope and runoff generation processes in the Ethiopian Highlands: The Ene-Chilala watershed

2020 ◽  
Vol 68 (4) ◽  
pp. 313-327
Author(s):  
Meseret B. Addisie ◽  
Getaneh K. Ayele ◽  
Nigus Hailu ◽  
Eddy J. Langendoen ◽  
Seifu A. Tilahun ◽  
...  
Keyword(s):  
Overland Flow ◽  
Infiltration Rate ◽  
Water Levels ◽  
Runoff Generation ◽  
Valley Bottom ◽  
Ethiopian Highlands ◽  
Infiltration Rates ◽  
Water Tables ◽  
Perched Aquifer ◽  
Hillslope Processes

AbstractEffective watershed planning requires an understanding of the hydrology. In the humid tropical monsoon climates and especially in volcanic highland regions such as the Ethiopian Highlands, the understanding of watershed processes is incomplete. The objective is to better understand the hydrology of the volcanic regions in the humid highlands by linking the hillslope processes with the discharge at the outlet. The Ene-Chilala watershed was selected for this study. The infiltration rate, piezometric water levels and discharge from two nested sub watersheds and at the watershed outlet were measured during a four-year period. Infiltration rates on the hillsides exceeded the rainfall intensity most of the time. The excess rain recharged a perched hillside aquifer. Water flowed through the perched aquifer as interflow to rivers and outlet. In addition, saturation excess overland flow was generated in the valley bottoms. Perched water tables heights were predicted by summing up the recharge over the travel time from the watershed divide. Travel times ranged from a few days for piezometers close to the divide to 40 days near the outlet. River discharge was simulated by adding the interflow from the upland to overland flow from the saturated valley bottom lands. Overland flow accounted only for one-fourth of the total flow. There was good agreement between predicted and observed discharge during the rain phase therefore the hillslope hydrologically processes were successfully linked with the discharge at the outlet.

scholarly journals Physically-based modelling of hydrological processes in a tropical headwater catchment (West Africa) – process representation and multi-criteria validation

2006 ◽  
Vol 10 (6) ◽  
pp. 829-847 ◽  
Author(s):  
S. Giertz ◽  
B. Diekkrüger ◽  
G. Steup
Keyword(s):  
Soil Moisture ◽  
Rainy Season ◽  
Overland Flow ◽  
Soil Layer ◽  
Hydrological Processes ◽  
Runoff Generation ◽  
Field Investigations ◽  
Physically Based ◽  
In The Beginning ◽  
Headwater Catchment

Abstract. The aim of the study was to test the applicability of a physically-based model to simulate the hydrological processes in a headwater catchment in Benin. Field investigations in the catchment have shown that lateral processes such as surface runoff and interflow are most important. Therefore, the 1-D SVAT-model SIMULAT was modified to a semi-distributed hillslope version (SIMULAT-H). Based on a good database, the model was evaluated in a multi-criteria validation using discharge, discharge components and soil moisture data. For the validation of discharge, good results were achieved for dry and wet years. The main differences were observable in the beginning of the rainy season. A comparison of the discharge components determined by hydro-chemical measurements with the simulation revealed that the model simulated the ratio of groundwater fluxes and fast runoff components correctly. For the validation of the discharge components of single events, larger differences were observable, which was partly caused by uncertainties in the precipitation data. The representation of the soil moisture dynamics by the model was good for the top soil layer. For deeper soil horizons, which are characterized by higher gravel content, the differences between simulated and measured soil moisture were larger. A good agreement of simulation results and field investigations was achieved for the runoff generation processes. Interflow is the predominant process on the upper and the middle slopes, while at the bottom of the hillslope groundwater recharge and – during the rainy season – saturated overland flow are important processes.

Dominant drivers of runoff in a slash-and-burn affected catchment in upland Eastern Madagascar

2021 ◽  
Author(s):  
Bob W. Zwartendijk ◽  
H.J. (Ilja) van Meerveld ◽  
Ryan J. Teuling ◽  
Chandra P. Ghimire ◽  
L. Adrian Bruijnzeel
Keyword(s):  
Soil Moisture ◽  
Overland Flow ◽  
Quantitative Information ◽  
Forest Loss ◽  
Runoff Generation ◽  
Catchment Scale ◽  
Valley Bottom ◽  
Antecedent Soil Moisture ◽  
Slash And Burn ◽  
Slash And Burn Agriculture

<p>In many tropical areas slash-and-burn agriculture is an important driver of forest loss. In areas where slash-and-burn agriculture has been practiced for decades, land cover is typically a mosaic of patches of remnant forest, fields under active cultivation, fallows in various stages of regrowth (ranging from young shrub to semi-mature), and degraded fire-climax grasslands. Although runoff generation mechanisms are expected to be different for these different patches, little quantitative information is available in this regard, particularly at the catchment scale and over longer time-scales (i.e., multiple slash-and-burn cycles).</p><p>We re-instrumented a 31 ha catchment in upland Eastern Madagascar, where slash-and-burn agriculture has been practiced for more than 70 years in 2015; it had been monitored between 1963 and 1972 as well<sup>1</sup>. We measured streamflow at two locations and overland flow and soil moisture for four hillside plots (0.05 – 1.93 ha): one plot under repeatedly coppiced and burned <em>Eucalyptus</em> and three plots under young shrub and tree fallows. One of the plots underwent rudimentary terracing in the past. We analysed the rainfall-runoff dynamics for 50 rainfall events (median 12 mm, maximum 71 mm).</p><p>For 60% of the events, the stormflow coefficient (minimum contributing area) was <3%, which is the proportion of valley-bottom wetlands and rice paddies in the catchment. Stable isotope sampling for five storm runoff events indicate a maximum total event-water contribution of 16%. However, instantaneous event-water contributions were as high as 66%. The hillside plot runoff response was dominated by saturation-excess overland flow and showed strong threshold behaviour in terms of the antecedent soil moisture storage in the upper 30 cm of the soil plus the event total rainfall amount (ASI + P). Average threshold values for overland flow occurrence ranged from 87 mm for the coppiced <em>Eucalyptus</em> to 137 mm for the young fallow plots (regardless of terrace presence). Stormflow also increased after an ASI+P-threshold was exceeded (100 mm based on the soil moisture sensors for the <em>Eucalyptus</em> plot and 150 mm for the sensors at the tree fallow plots).</p><p>These results indicate an increased hydrological connectivity between hillslopes and valley bottom under wetter conditions and that stormflow in the study catchment is strongly affected by variations in seasonal rainfall. The results will be used to validate a hydrological model to determine the net effect of concurrent changes in soil infiltrability and vegetation water use associated with forest loss and recovery on stormflow totals and the seasonal flow regime.</p><p><strong><sup>1</sup></strong>Bailly, C., de Coignac, G.B., Malvos, C., Ningre, J.M., and Sarrailh, J.M. (1974). Étude de l'influence du couvert naturel et de ses modifications á Madagascar. Expérimentations en bassins versants élémentaires. Cahiers Scientifiques, 4. Centre Scientifique Forestier Tropical, Nogent-sur-Marne, France, 114 pp.</p>

Understanding the role of different geographical features in the hydrological response of humid mountainous areas through a stepwise clustering scheme

2021 ◽  
Author(s):  
Yaqian Yang ◽  
Jintao Liu
Keyword(s):  
Bulk Density ◽  
Optimal Parameter ◽  
Soil Bulk Density ◽  
Model Parameters ◽  
Hydrological Response ◽  
Runoff Generation ◽  
Explanatory Variables ◽  
Hydrological Responses ◽  
Rainfall Patterns

<p>In the mountainous basins with less anthropogenic influence, the hydrological function is mainly affected by climate and landscape, which makes it possible to measure hydrological similarity indirectly by geographical features. Due to the mechanisms of runoff generation can vary geographically, in this study, a simple stepwise clustering scheme was proposed to explore the role of geographical features at different spatial hierarchy in indicating hydrological response. Research methods mainly include (1) Stepwise regression was used to quantitatively show the correlation between 35 geographical features and 35 flow features and identify the important explanatory variables for hydrological response; (2) 64 basins were divided by stepwise clustering scheme, and the overall ability of the scheme to capture hydrological similarity was tested by comparing the optimal parameters; (3) The hydrological similarity of basin groups was measured by the leave-one cross validation of hydrological model parameters. The results showed that: (1) Rainfall features, elevation, slope and soil bulk density are the main explanatory variables. (2) The NSE of basin groups based on stepwise clustering is 0.64, reaches 80% of the optimal parameter sets (NSE=0.80). The NSE of 90% basins is greater than 0.5, 80% is greater than 0.6, and 49% is greater than 0.7. (3) In humid areas, the hydrological responses of the basins with more uniform monthly rainfall and more abundant summer rainfall are more similar, e.g., the NSE of Class 4 is 0.77. Under similar rainfall patterns, the hydrological responses of the basins with higher average altitude, greater slope, more convergent of shape and richer vegetation are more similar, e.g., the NSE of Class 3-2 is 0.72 and that of Class 1-2 is 0.70. In the case of similar rainfall patterns and landforms, the hydrological responses of the basins with smaller soil bulk density are more similar, e.g., the NSE of Class 3-2-2 is 0.80. In conclusion, the stepwise clustering enhances the interpretability of basin classification, and the effect of different geographical features on hydrological response can show the applicability of hydrological simulation in ungauged basins.</p>

scholarly journals Technical Note: Updating procedure for flood forecasting with conceptual HBV-type models

2006 ◽  
Vol 10 (6) ◽  
pp. 783-788 ◽  
Author(s):  
Th. Wöhling ◽  
F. Lennartz ◽  
M. Zappa
Keyword(s):  
Flood Forecasting ◽  
Technical Note ◽  
Rainfall Runoff ◽  
Runoff Generation ◽  
Mountainous Catchments ◽  
Rainfall Runoff Model ◽  
Updating Procedure ◽  
Global And Local ◽  
Hbv Model ◽  
Runoff Model

Abstract. Flood forecasting is of increasing importance as it comes to an increasing variability in global and local climates. But rainfall-runoff models are far from being perfect. In order to achieve a better prediction for emerging flood events, the model outputs have to be continuously updated. This contribution introduces a rather simple, yet effective updating procedure for the conceptual semi-distributed rainfall-runoff model PREVAH, whose runoff generation module relies on similar algorithms as the HBV-Model. The current conditions of the system, i.e. the contents of the upper soil reservoirs, are updated by the proposed method. The testing of the updating procedure on data from two mountainous catchments in Switzerland reveals a significant increase in prediction accuracy with regards to peak flow.

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

2010 ◽  
Vol 7 (5) ◽  
pp. 8091-8124 ◽  
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.

Driving factors of non-linearity rainfall-runoff relationships at different time scales in small Mediterranean-climate catchments

2020 ◽  
Author(s):  
Josep Fortesa ◽  
Jérôme Latron ◽  
Julián García-Comendador ◽  
Miquel Tomàs-Burguera ◽  
Jaume Company ◽  
...  
Keyword(s):  
Mediterranean Climate ◽  
Annual Rainfall ◽  
Land Uses ◽  
Hydrological Response ◽  
Rainfall Runoff ◽  
Runoff Generation ◽  
Event Scale ◽  
Annual Variability ◽  
Temporal And Spatial ◽  
Annual Scale

<p>The complexity of Mediterranean fluvial systems is caused by the multiple temporal and spatial heterogeneity in the relationships between the natural and human-induced abiotic and biotic variables. Accordingly, Mediterranean rivers are characterized by a large heterogeneity in hydrological regimes promoting significant temporal and spatial differences in the hydrological response.</p><p>This research investigates the non-linearity in the rainfall-runoff relationship at multiple temporal scales to achieve a better understanding of the hydrological response in representative small Mediterranean-climate catchments (i.e., < 10 km<sup>2</sup>). Rainfall-runoff was evaluated at annual and event scales. At annual scale, data from 43 catchments were collected to assess the influence of lithology on runoff response. At event scale, 203 events from 12 catchments were classified according to (a) seasonal occurrence (autumn, winter, spring or summer), (b) pervious or impervious lithology and (c) main land use (agricultural, agroforestry, forest or shrub). Besides, the inter- and intra-annual variability of the rainfall-runoff and the temporal downscaling (i.e., annual to event scale) was studied in Es Fangar Creek catchment (3.35 km<sup>2</sup>; Mallorca, Spain) during five hydrological years (2012-2017).</p><p>The assessment of rainfall-runoff relationships at annual scale in small Mediterranean-climate catchments showed a strong linearity in the hydrological response due to the importance of the annual rainfall amount. However, lithology effects on runoff generation explained an increase of the scattering in these relationships because pervious and impervious materials triggered larger and lower runoff contribution respectively. Although the significant correlation between rainfall and runoff, Es Fangar Creek dataset illustrated a huge intra-annual variability of the rainfall-runoff relationship as seasonal rainfall and evapotranspiration dynamics controlled the runoff response. These dynamics were observed in the average seasonal runoff coefficients, decreasing from winter to summer. These differences should be considered as a starting point of the non-linearity generation in the rainfall-runoff relationships at event scale.</p><p>At event scale, lineal and non-lineal performances were observed in the rainfall-runoff relationships in small Mediterranean-climate catchments suggesting that different factors conditioned the runoff response. Total rainfall was the most significant driver factor although the interaction between seasonality and the spatial diversity of lithology and land uses at catchment scale also played an important role on runoff generation. Thus, the highest correlations at seasonal scale were observed in those events occurred in winter and spring when the highest water reserves favoured the runoff response. Lithology caused higher dispersion in rainfall-runoff relationships at event scale in the set of small Mediterranean-climate catchments because pervious materials required higher antecedent wetness conditions. Agricultural land uses promoted the highest runoff generation. </p><p>These findings will improve the comprehension of hydrological processes as the temporal downscaling of rainfall-runoff linked to the driven factors with the linearity and non-linearity knowledge is needed for accuracy and precision into hydrological modelling at event scale.</p><p>This work was supported by the research project CGL2017-88200-R “Functional hydrological and sediment connectivity at Mediterranean catchments: global change scenarios –MEDhyCON2” funded by the Spanish Ministry of Science, Innovation and Universities, the Spanish Agency of Research (AEI) and the European Regional Development Funds (ERDF). </p>

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