scholarly journals Improved Curve Number Estimation in SWAT by Reflecting the Effect of Rainfall Intensity on Runoff Generation

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 163 ◽  
Author(s):  
Dejian Zhang ◽  
Qiaoyin Lin ◽  
Xingwei Chen ◽  
Tian Chai
Keyword(s):  
Rainfall Intensity ◽  
Assessment Tool ◽  
Flow Simulation ◽  
Daily Rainfall ◽  
Curve Number ◽  
Base Flow ◽  
Data Sets ◽  
Rainfall Runoff ◽  
Runoff Generation ◽  
The Relationship

Determining the amount of rainfall that will eventually become runoff and its pathway is a crucial process in hydrological modelling. We proposed a method to better estimate curve number by adding an additional component (AC) to better account for the effects of daily rainfall intensity on rainfall-runoff generation. This AC is determined by a regression equation developed from the relationship between the AC series derived from fine-tuned calibration processes and observed rainfall series. When incorporated into the Soil and Water Assessment Tool and tested in the Anxi Watershed, it is found, overall, the modified SWAT (SWAT-ICN) outperformed the original SWAT (SWAT-CN) in terms of stream flow, base flow, and annual extreme flow simulation. These models were further evaluated with the data sets of two adjacent watersheds. Similar results were achieved, indicating the ability of the proposed method to better estimate curve number.

scholarly journals Rainfall-Runoff Modeling Using the HEC-HMS Model for the Al-Adhaim River Catchment, Northern Iraq

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 58
Author(s):  
Ahmed Naseh Ahmed Hamdan ◽  
Suhad Almuktar ◽  
Miklas Scholz
Keyword(s):  
Geographical Information Systems ◽  
Hydrological Model ◽  
Daily Rainfall ◽  
Curve Number ◽  
Geographical Information ◽  
Coefficient Of Determination ◽  
Rainfall Runoff ◽  
Time Step ◽  
River Catchment ◽  
Northern Iraq

It has become necessary to estimate the quantities of runoff by knowing the amount of rainfall to calculate the required quantities of water storage in reservoirs and to determine the likelihood of flooding. The present study deals with the development of a hydrological model named Hydrologic Engineering Center (HEC-HMS), which uses Digital Elevation Models (DEM). This hydrological model was used by means of the Geospatial Hydrologic Modeling Extension (HEC-GeoHMS) and Geographical Information Systems (GIS) to identify the discharge of the Al-Adhaim River catchment and embankment dam in Iraq by simulated rainfall-runoff processes. The meteorological models were developed within the HEC-HMS from the recorded daily rainfall data for the hydrological years 2015 to 2018. The control specifications were defined for the specified period and one day time step. The Soil Conservation Service-Curve number (SCS-CN), SCS Unit Hydrograph and Muskingum methods were used for loss, transformation and routing calculations, respectively. The model was simulated for two years for calibration and one year for verification of the daily rainfall values. The results showed that both observed and simulated hydrographs were highly correlated. The model’s performance was evaluated by using a coefficient of determination of 90% for calibration and verification. The dam’s discharge for the considered period was successfully simulated but slightly overestimated. The results indicated that the model is suitable for hydrological simulations in the Al-Adhaim river catchment.

Ingredients of German flood events

2020 ◽  
Author(s):  
Ralf Merz ◽  
Larisa Tarasova ◽  
Stefano Basso
Keyword(s):  
Soil Moisture ◽  
Snow Cover ◽  
Rainfall Intensity ◽  
Machine Learning Techniques ◽  
Rainfall Runoff ◽  
Flood Events ◽  
Runoff Generation ◽  
Regional Variability ◽  
Large Variability ◽  
Runoff Events

<p>Floods can be caused by a large variety of different processes, such as short, but intense rainfall bursts, long rainfall events, which are wetting up substantial parts of the catchment, or rain on snow cover or frozen soils. Although there is a plethora on studies analysing or modelling rainfall-runoff processes, it is still not well understood, what rainfall and runoff generation conditions are needed to generate flood runoff and how these characteristics vary between catchments. In this databased approach we decipher the ingredients of flood events occurred in 161 catchments across Germany. For each catchment rainfall-runoff events are separated from observed time series for the period 1950-2013, resulting in about 170,000 single events. A peak-over-threshold approach is used to select flood events out of these runoff events. For each event, spatially and temporally distributed rainfall and runoff generation characteristics, such as snow cover and soil moisture, as well as their interaction are derived. Then we decipher those event characteristics controlling flood event occurrence by using machine learning techniques.</p><p>On average, the most important event characteristic controlling flood occurrence in Germany is, as expected, event rainfall volume, followed by the overlap of rainfall and soil moisture and the extent of wet areas in the catchment (area with high soil moisture content). Rainfall intensity is another important characteristic. However, a large variability in its importance is noticeable between dryer catchments where short rainfall floods occur regularly and wetter catchments, where rainfall intensity might be less important for flood generation. To analyse the regional variability of flood ingredients, we cluster the catchments according to similarity in their flood controlling event characteristics and test how good the flood occurrence can be predicted from regionalised event characteristics. Finally, we analyse the regional variability of the flood ingredients in the light of climate and landscape catchment characteristics.</p>

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 Relationship between Surface Temperature and Extreme Rainfalls: A Multi-Time-Scale and Event-Based Analysis*

2014 ◽  
Vol 15 (5) ◽  
pp. 1999-2011 ◽  
Author(s):  
Gérémy Panthou ◽  
Alain Mailhot ◽  
Edward Laurence ◽  
Guillaume Talbot
Keyword(s):  
Relative Humidity ◽  
Rainfall Intensity ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Limiting Factor ◽  
Coastal Regions ◽  
Dewpoint Temperature ◽  
Hourly Rainfall ◽  
Event Based ◽  
The Relationship

Abstract Recent studies have examined the relationship between the intensity of extreme rainfall and temperature. Two main reasons justify this interest. First, the moisture-holding capacity of the atmosphere is governed by the Clausius–Clapeyron (CC) equation. Second, the temperature dependence of extreme-intensity rainfalls should follow a similar relationship assuming relative humidity remains constant and extreme rainfalls are driven by the actual water content of the atmosphere. The relationship between extreme rainfall intensity and air temperature (Pextr–Ta) was assessed by analyzing maximum daily rainfall intensities for durations ranging from 5 min to 12 h for more than 100 meteorological stations across Canada. Different factors that could influence this relationship have been analyzed. It appears that the duration and the climatic region have a strong influence on this relationship. For short durations, the Pextr–Ta relationship is close to the CC scaling for coastal regions while a super-CC scaling followed by an upper limit is observed for inland regions. As the duration increases, the slope of the relationship Pextr–Ta decreases for all regions. The shape of the Pextr–Ta curve is not sensitive to the percentile or season. Complementary analyses have been carried out to understand the departures from the expected Clausius–Clapeyron scaling. The relationship between dewpoint temperature and extreme rainfall intensity shows that the relative humidity is a limiting factor for inland regions, but not for coastal regions. Using hourly rainfall series, an event-based analysis is proposed in order to understand other deviations (super-CC, sub-CC, and monotonic decrease). The analyses suggest that the observed scaling is primarily due to the rainfall event dynamic.

scholarly journals Comparison of Three Daily Rainfall-Runoff Hydrological Models Using Four Evapotranspiration Models in Four Small Forested Watersheds with Different Land Cover in South-Central Chile

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3191
Author(s):  
Neftali Flores ◽  
Rolando Rodríguez ◽  
Santiago Yépez ◽  
Victor Osores ◽  
Pedro Rau ◽  
...  
Keyword(s):  
Flow Simulation ◽  
Daily Rainfall ◽  
Hydrological Models ◽  
Rainfall Runoff ◽  
Hydrologic Models ◽  
Central Chile ◽  
South Central ◽  
Robust Model ◽  
Sensitive Parameters

We used the lumped rainfall–runoff hydrologic models Génie Rural à 4, 5, 6 paramètres Journalier (GR4J, GR5J and GR6J) to evaluate the most robust model for simulating discharge on four forested small catchments (<40 ha) in south-central Chile. Different evapotranspiration methods were evaluated: Oudin, Hargreaves–Samani and Priestley–Taylor. Oudin’s model allows the achievement of the highest efficiencies in the flow simulation. The more sensitive parameters for each model were identified through a Generalized Probability Uncertainty Estimation (GLUE) model. Our results demonstrate that the three hydrological models were capable of efficiently simulating flow in the four study catchments. However, the GR6J model obtained the most satisfactory results in terms of simulated to measured streamflow closeness. In general, the three models tended to underestimate peak flow, as well as underestimate and overestimate flow events in most of the in situ observations, according to the probability of non-exceedance. We also evaluated the models’ performance in a simulation of summer discharge due to the importance of downstream water supply in the months of greatest scarcity. Again, we found that GR6J obtained the most efficient simulations.

scholarly journals Hydrological modelling of the karst Ljubljanica River catchment using lumped conceptual model

2018 ◽  
pp. 87-100 ◽  
Author(s):  
Cenk Sezen ◽  
Nejc Bezak ◽  
Mojca Šraj
Keyword(s):  
Water System ◽  
Flow Simulation ◽  
Resource Planning ◽  
Base Flow ◽  
Low Flow ◽  
Flow Index ◽  
Rainfall Runoff ◽  
River Catchment ◽  
Simulation Performance

Modelling rainfall runoff is important for several human activities. For example, rainfall runoff models are needed for water resource planning and water system design. In this regard, the daily runoff was modelled using the Genie Rural, a 4-parameter Journalier (GR4J), Genie Rural, a 6-parameter Journalier (GR6J), and the CemaNeige GR6J lumped conceptual models that were developed by the IRSTEA Hydrology Group. The main difference among the tested models is in the complexity and processes that are considered in the various model versions. As a case study, the non-homogeneous mostly karst Ljubljanica River catchment down to the Moste discharge gauging station was selected. Models were evaluated using various efficiency criteria. For example, base flow index (BFI) was calculated for the results of all tested models and observed discharges in order to compare low flow simulation performance. Based on the presented results we can conclude that in case of the non-homogeneous and karst Ljubljanica catchment the CemaNeige GR6J yields better modelling results compared to the GR4J and GR6J models. Compared to the GR6J and GR4J model versions, the CemaNeige CR6J also includes the snow module and improved methodology for the low-flow simulations that are also included in the GR6J model version.

scholarly journals Aplicação do Modelo Soil And Water Assesment Tool (Swat) na bacia hidrográfica do Ribeirão Taquaruçu.

2021 ◽  
pp. 159-187
Author(s):  
FERNÁN VERGARA ◽  
◽  
FERNANDA NODA ◽  
DENER SOUZA ◽  
GIRLENE FIGUEIREDO MACIEL ◽  
...  
Keyword(s):  
Assessment Tool ◽  
Swat Model ◽  
Flow Simulation ◽  
Curve Number ◽  
Hydrological Models ◽  
Objective Functions ◽  
Object Of Study ◽  
Influential Parameters ◽  
Water Assessment ◽  
Soil And Water

The hydrological models are important tools to evaluate the hydrological behavior of watersheds, helping in the decision making. Thus, this study had the objective of evaluating the performance of the Soil and Water Assessment Tool (SWAT) model in the flow simulation in the Ribeirão Taquaruçu Hydrographic Basin. Flow data from two fluviometric stations were used from April 2013 to August 2015. The results of the sensitivity analysis indicated that the most influential parameters are the SOL_K (saturated hydraulic conductivity of the soil) and CN2 (curve number for the condition II). The Nash-Sutcliffe (NSE) objective functions and the determination coefficient (R2) indicated, in the calibration period, the following values: -0.05 and 0.55 (sub-basin 1); 0.51 (sub-basin 3), respectively. In the validation period, the following results were presented for NSE and R2: 0.44 and 0.54 (sub-basin 1); 0.24 and 0.29 (sub-basin 3), in that order. Considering that the object of study is responsible for a large part of the water supply of Palmas - TO and that the program was unable to simulate the minimum flows adequately, the results are considered unsatisfactory

Impact of land use/cover change on the relationship between precipitation and runoff in typical area

2018 ◽  
Vol 9 (2) ◽  
pp. 261-274 ◽  
Author(s):  
Bao-qi Li ◽  
Wei-hua Xiao ◽  
Yi-cheng Wang ◽  
Ming-zhi Yang ◽  
Ya Huang
Keyword(s):  
Land Use ◽  
River Basin ◽  
Assessment Tool ◽  
Forest Land ◽  
Runoff Generation ◽  
Dry Land ◽  
Unused Land ◽  
Land Use Types ◽  
The Impact ◽  
The Relationship

Abstract To study the impact of land use/cover change (LUCC), the relationship between precipitation and runoff was investigated. Our main objective was to ensure reasonable development, management, and sustainable utilization of water resources at a watershed scale. To investigate the relationship between precipitation and runoff, a SWAT (Soil and Water Assessment Tool) model was developed by analyzing LUCC in Naoli River basin. Then, runoff response was analyzed under different LUCC conditions. The contribution coefficient of different land use types to runoff was calculated. The results of this research study are as follows. From 1986 to 2014, dry land, forest land, paddy fields, and unused land were the major land use types, accounting for more than 93% of the total catchment. On the other hand, grass land, building land, and water bodies accounted for a small proportion. Among the four main land use types, the contribution coefficient of forest land was 3.10 mm·km−2. This indicates that forest land was suitable for runoff generation. The contribution coefficient of dry land, unused land (fluvial wetland in Naoli River basin), and paddy field are −0.11, −0.37, and −0.83 mm·km−2, respectively. This implies that these three land use types were adverse factors for runoff generation.

scholarly journals New baseflow separation and recession analysis approaches for streamflow

2014 ◽  
Vol 11 (6) ◽  
pp. 7089-7131 ◽  
Author(s):  
M. K. Stewart
Keyword(s):  
Driving Force ◽  
Water Storage ◽  
Separation Method ◽  
Rainfall Runoff ◽  
Runoff Generation ◽  
Linear Quadratic ◽  
Baseflow Separation ◽  
Recession Analysis ◽  
Different Origins ◽  
The Relationship

Abstract. Understanding and modelling the relationship between rainfall and runoff has been a driving force in hydrology for many years. Baseflow separation and recession analysis have been two of the main tools for understanding runoff generation in catchments, but there are many different methods for each and no consensus on how best to apply them. A new baseflow separation method is presented, which is justified by being based generally on the more objective tracer separation methods and by being optimised by fitting to the recession hydrograph. Using this baseflow separation method, the thesis is advanced that recession analysis should be applied to the separated components (quickflow and baseflow), because of their very different origins and characteristics, rather than to the streamflow itself because analysing the latter alone gives misleading results. Applying baseflow separation before recession analysis sheds new light on water storage in catchments and may resolve some current problems with recession analysis. It may also have implications for rainfall–runoff modelling. Among other things it shows that both quickflow and baseflow reservoirs have non-linear (quadratic) characteristics in the studied catchment (Glendhu, New Zealand).

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