scholarly journals Multi-objective regionalisation for lake level simulation, the case of Lake Tana in the Upper Blue Nile, Ethiopia

2010 ◽  
Vol 7 (5) ◽  
pp. 7341-7381
Author(s):  
T. H. M. Rientjes ◽  
B. U. J. Perera ◽  
A. T. Haile ◽  
P. Reggiani
Keyword(s):  
Water Balance ◽  
Lake Level ◽  
Ad Hoc ◽  
Relative Volume ◽  
Model Parameters ◽  
Lake Levels ◽  
Ungauged Catchments ◽  
Time Step ◽  
Lake Tana ◽  
Multi Objective

Abstract. The aim in this study is to simulate lake levels of Lake Tana by solving the water balance at daily time step. Since 42% of the basin is ungauged regionalisation procedures are applied. We examine the predictive capability of a regionalisation approach that combines multi-objective calibration of a simple conceptual model and multi regression analyses to establish relations between model parameters and catchment characteristics. Recently few studies are presented on lake level simulation of Lake Tana. In these studies the water balance of the lake is closed by estimation of runoff contributions from ungauged catchments. Studies partly relied on simple ad-hoc procedures of area comparison to estimate runoff from ungauged catchments. In this study a regional model is developed that relies on principles of similarity of catchments. For runoff modelling the HVB-96 model is selected while multi-objective model calibration is by a Monte Carlo procedure. Assessment of the lake water balance was established by comparing measured to estimated lake levels. Results of daily lake level simulation show a water balance closure term of 85 mm and a relative volume error of 2.17%. Results show runoff from ungauged catchments of 527 mm per year for the simulation period 1994 to 2003 that is approximately 30% of Lake Tana stream flow inflow. Compared to previous works this closure term is smallest.

scholarly journals Regionalisation for lake level simulation – the case of Lake Tana in the Upper Blue Nile, Ethiopia

2011 ◽  
Vol 15 (4) ◽  
pp. 1167-1183 ◽  
Author(s):  
T. H. M. Rientjes ◽  
B. U. J. Perera ◽  
A. T. Haile ◽  
P. Reggiani ◽  
L. P. Muthuwatta
Keyword(s):  
Water Balance ◽  
Model Calibration ◽  
Lake Level ◽  
Regional Model ◽  
Model Parameters ◽  
Ungauged Catchments ◽  
Time Step ◽  
Lake Tana ◽  
Multi Objective ◽  
Objective Model

Abstract. In this study lake levels of Lake Tana are simulated at daily time step by solving the water balance for all inflow and outflow processes. Since nearly 62% of the Lake Tana basin area is ungauged a regionalisation procedure is applied to estimate lake inflows from ungauged catchments. The procedure combines automated multi-objective calibration of a simple conceptual model and multiple regression analyses to establish relations between model parameters and catchment characteristics. A relatively small number of studies are presented on Lake Tana's water balance. In most studies the water balance is solved at monthly time step and the water balance is simply closed by runoff contributions from ungauged catchments. Studies partly relied on simple ad-hoc procedures of area comparison to estimate runoff from ungauged catchments. In this study a regional model is developed that relies on principles of similarity of catchments characteristics. For runoff modelling the HBV-96 model is selected while multi-objective model calibration is by a Monte Carlo procedure. We aim to assess the closure term of Lake Tana's water balance, to assess model parameter uncertainty and to evaluate effectiveness of a multi-objective model calibration approach to make hydrological modeling results more plausible. For the gauged catchments, model performance is assessed by the Nash-Sutcliffe coefficient and Relative Volumetric Error and resulted in satisfactory to good performance for six, large catchments. The regional model is validated and indicated satisfactory to good performance in most cases. Results show that runoff from ungauged catchments is as large as 527 mm per year for the simulation period and amounts to approximately 30% of Lake Tana stream inflow. Results of daily lake level simulation over the simulation period 1994–2003 show a water balance closure term of 85 mm per year that accounts to 2.7% of the total lake inflow. Lake level simulations are assessed by Nash Sutcliffe (0.91) and Relative Volume Error (2.71%) performance measures.

scholarly journals Estimation of parameters in a distributed precipitation-runoff model for Norway

2003 ◽  
Vol 7 (3) ◽  
pp. 304-316 ◽  
Author(s):  
S. Beldring ◽  
K. Engeland ◽  
L. A. Roald ◽  
N. R. Sælthun ◽  
A. Voksø
Keyword(s):  
Land Surface ◽  
Distributed Model ◽  
Small Scale ◽  
Model Parameters ◽  
Estimation Of Parameters ◽  
Ungauged Catchments ◽  
Time Step ◽  
Landscape Characteristics ◽  
Average Annual Runoff ◽  
Scale Properties

Abstract. A distributed version of the HBV-model using 1 km2 grid cells and daily time step was used to simulate runoff from the entire land surface of Norway for the period 1961-1990. The model was sensitive to changes in small scale properties of the land surface and the climatic input data, through explicit representation of differences between model elements, and by implicit consideration of sub-grid variations in moisture status. A geographically transferable set of model parameters was determined by a multi-criteria calibration strategy, which simultaneously minimised the residuals between model simulated and observed runoff from 141 Norwegian catchments located in areas with different runoff regimes and landscape characteristics. Model discretisation units with identical landscape classification were assigned similar parameter values. Model performance was evaluated by simulating discharge from 43 independent catchments. Finally, a river routing procedure using a kinematic wave approximation to open channel flow was introduced in the model, and discharges from three additional catchments were calculated and compared with observations. The model was used to produce a map of average annual runoff for Norway for the period 1961-1990. Keywords: distributed model, multi-criteria calibration, global parameters, ungauged catchments.

scholarly journals Catchment modeling and model transferability in upper Blue Nile Basin, Lake Tana, Ethiopia

2008 ◽  
Vol 5 (2) ◽  
pp. 811-842 ◽  
Author(s):  
A. S. Gragne ◽  
S. Uhlenbrook ◽  
Y. Mohammed ◽  
S. Kebede
Keyword(s):  
Water Resources ◽  
Water Resource Management ◽  
Model Parameters ◽  
Hydrological Process ◽  
Runoff Generation ◽  
Time Step ◽  
Lake Tana ◽  
Blue Nile ◽  
Model Transferability ◽  
Catchment Modeling

Abstract. Understanding spatial and temporal distribution of water resources has an important role for water resource management. To understand water balance dynamics and runoff generation mechanisms at the Gilgel Abay catchment (a major tributary into lake Tana, source of Blue Nile, Ethiopia) and to evaluate model transferability, catchment modeling was conducted using the conceptual hydrological model HBV. The catchment of the Gigel Abay was sub-divided into two gauged sub-catchments (Upper Gilgel Abay, UGASC, and Koga, KSC) and one ungauged sub-catchment. Manual calibration of the daily models for three different catchment representations (CRs): (i) lumped, (ii) lumped with multiple vegetation zones, and (iii) semi-distributed with vegetations zone and elevation zones, showed good to satisfactory model performance (Nash-Sutcliffe efficiency values, Reff>0.75 and >0.6, respectively, for UGASC and KSC). The change of the time step to fifteen and thirty days resulted in very good model performances in both sub-catchments (Reff>0.8). The model parameter transferability tests conducted on the daily models showed poor performance in both sub-catchments, whereas the fifteen and thirty days models yielded high Reff values using transferred parameter sets. This together with the sensitivity analysis carried out after Monte Carlo simulations (1 000 000 model runs) per CR explained the reason behind the difference in hydrologic behaviors of the two sub-catchments UGASC and KSC. The dissimilarity in response pattern of the sub-catchments was caused by the presence of dambos in KSC and differences in the topography between UGASC and KSC. Hence, transferring model parameters from the view of describing hydrological process was found to be not feasible for all models. On the other hand, from a water resources management perspective the results obtained by transferring parameters of the larger time step model were acceptable.

scholarly journals Quantifying the Regional Water Balance of the Ethiopian Rift Valley Lake Basin Using an Uncertainty Estimation Framework

2021 ◽  
Author(s):  
Tesfalem Abraham ◽  
Yan Liu ◽  
Sirak Tekleab ◽  
Andreas Hartmann
Keyword(s):  
Water Balance ◽  
Rift Valley ◽  
Model Parameters ◽  
Lake Basin ◽  
Climatic Data ◽  
Ungauged Catchments ◽  
Regional Regression ◽  
Validation Parameters ◽  
Global Precipitation ◽  
Regional Water

Abstract. In Ethiopia more than 80 % of big freshwater lakes are located in the Rift Valley Lake Basin (RVLB), serving over 15 million people a multipurpose water supply. The basin covers an area of 53,035 km2, and most of the catchments recharging these lakes are ungauged and their water balance is not well quantified, hence limiting the development of appropriate water resource management strategies. Prediction for ungauged basins (PUB) has demonstrated its effectiveness in hydro-climatic data-rich regions. However, these approaches are not well evaluated in climatic data-limited conditions and the consequent uncertainty is not adequately quantified. In this study we use the Hydrologiska Byråns Vattenbalansavdelning (HBV) model to simulate streamflow at a regional scale using global precipitation and potential evapotranspiration products as forcings. We develop and apply a Monte-Carlo scheme to estimate model parameters and quantify uncertainty at 16 catchments in the basin where gauging stations are available. Out of these 16, we use the 14 most reliable catchments to derive the best regional regression model. We use three different strategies to extract possible parameter sets for regionalization by correlating the best calibration parameters, the best validation parameters, and parameters that give the most stable predictions with catchment properties that are available throughout the basin. A weighting scheme in the regional regression accounts for parameter uncertainty in the calibration. A spatial cross-validation is applied multiple times to test the quality of the regionalization and to estimate the regionalization uncertainty. Our results show that, other than the commonly used best-calibrated parameters, the best parameter sets of the validation period provide the most robust estimates of regionalized parameters. We then apply the regionalized parameter sets to the remaining 35 ungauged catchments in the RVLB to provide regional water balance estimations, including quantifications of regionalization uncertainty. The uncertainties of elasticities from the regionalization in the ungauged catchments are higher than those obtained from the simulations in the gauged catchments. With these results, our study provides a new procedure to use global precipitation and evapotranspiration products to predict and evaluate streamflow simulation for hydro-climatically data-scarce regions considering uncertainty. This procedure enhances the confidence to understand the water balance of under-represented regions like ours and supports the planning and development of water resources.

scholarly journals A conceptual model of daily water balance following partial clearing from forest to pasture

2006 ◽  
Vol 10 (3) ◽  
pp. 321-337 ◽  
Author(s):  
M. A. Bari ◽  
K. R. J. Smettem
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Soil Depth ◽  
Groundwater Depth ◽  
Balance Model ◽  
Model Parameters ◽  
Stream Length ◽  
Time Step ◽  
Moisture Balance ◽  
Soil Moisture Balance

Abstract. A simple conceptual water balance model representing the streamflow generation processes on a daily time step following land use change is presented. The model consists of five stores: (i) Dry, Wet and Subsurface Stores for vertical and lateral water flow, (ii) a transient Stream zone Store (iii) a saturated Goundwater Store. The soil moisture balance in the top soil Dry and Wet Stores are the most important components of the model and characterize the dynamically varying saturated areas responsible for surface runoff, interflow and deep percolation. The Subsurface Store describes the unsaturated soil moisture balance, extraction of percolated water by vegetation and groundwater recharge. The Groundwater Store controls the baseflow to stream (if any) and the groundwater contribution to the stream zone saturated areas. The daily model was developed following a downward approach by analysing data from Ernies (control) and Lemon (53% cleared) catchments in Western Australia and elaborating a monthly model. The daily model performed very well in simulating daily flow generation processes for both catchments. Most of the model parameters were incorporated a priori from catchment attributes such as surface slope, soil depth, porosity, stream length and initial groundwater depth, and some were calibrated by matching the observed and predicted hydrographs. The predicted groundwater depth, and streamflow volumes across all time steps from daily to monthly to annual were in close agreement with observations for both catchments.

scholarly journals Water balance modeling of Upper Blue Nile catchments using a top-down approach

2010 ◽  
Vol 7 (5) ◽  
pp. 6851-6886 ◽  
Author(s):  
S. Tekleab ◽  
S. Uhlenbrook ◽  
Y. Mohamed ◽  
H. H. G. Savenije ◽  
S. Ayalew ◽  
...  
Keyword(s):  
Water Balance ◽  
Model Complexity ◽  
Model Parameters ◽  
Nile Basin ◽  
Top Down ◽  
Ungauged Catchments ◽  
Blue Nile ◽  
Blue Nile Basin ◽  
High Flows ◽  
Upper Blue Nile Basin

Abstract. The hydrological behavior and functioning of twenty catchments in the Upper Blue Nile basin have been analyzed using a top-down modeling approach that is based on Budyko's hypotheses. The objective is to obtain better understanding of catchment response for prediction in ungauged catchments. The water balance analysis using Budyko-type curve at annual scale reveals that the aridity index does not exert a first order control in most of the catchments. This implies the need to increase model complexity to a monthly time scale to include the effects of seasonal soil moisture dynamics. The dynamic water balance model used in this study predicts the direct runoff and other processes based on limit concept. The uncertainty of model parameters has been assessed using the GLUE (Generalized Likelihood Uncertainty Estimation). The results show that the majority of the parameters are reasonably well identifiable. Moreover, a multi-objective model calibration strategy has been employed within the GLUE framework to emphasize the different aspects of the hydrographs on low and high flows. The model has been calibrated and validated against observed streamflow time series and it shows good performance for the twenty catchments of the upper Blue Nile. During the calibration period (1995–2000) the Nash and Sutcliffe coefficient of efficiency for monthly flow prediction varied between 0.52 to 0.93 during high flows, while it varied between 0.32 to 0.90 during low flows (logarithms of flow series). The model is parsimonious and it is suggested that the resulting parameters can be used to predict monthly stream flows in the ungauged catchments of the Upper Blue Nile basin, which accounts about 60% of total Nile basin flow.

scholarly journals Modeling on naturalization of inflow and outflow nutrients sources of Blue Nile River at the Lake Tana in Basaltic Plateau of Ethiopia

2020 ◽  
Author(s):  
Asimamaw Nigusie Asitatikie ◽  
Endalkachew Diress Nigussie
Keyword(s):  
Water Balance ◽  
Water Level ◽  
Lake Level ◽  
Maximum Amplitude ◽  
Nile River ◽  
Data Sets ◽  
Regression Analyses ◽  
Lake Tana ◽  
Different Seasons ◽  
Natural Characteristics

Abstract Lake Tana is the largest natural reservoir in Ethiopia and the head water of Abbay basin. However, after building of an irrigation weir and further lying Tunnel to Tana Belles, Lake Tana maximum amplitude of water level canges from 2.18 to 3.56 m that differ substantially in 1.38 m from amplitude of natural water level fluctuation. Understanding the natural characteristics of the Lake is important to know its water balance and for sustainable development. But it is difficult to study the natural characteristics of the Lake and its water balance using the regulated water level and outflow data sets. Thus it is evident that the regulated water level and outflow data sets have to be first naturalized before they are used for any analysis and modeling. Lake level and outflow data that have been collected since 1976 were considered to assess the regulation effect and then for naturalization. Inflows to the Lake from the main tributaries have also been collected to find if there are any correlations with either the Lake Level and/or the outflow. Regression analyses were used to develop the naturalization models. The regression analyses of flows from Gilgel Abay and Gummar with Lake Level shows that there is a very good correlation between them in different seasons. Besides, same has also been observed between Lake Level and out flow. These relationships can be used to naturalize the regulated outflow and water level.

scholarly journals How does climate change affect mesoscale catchments in Switzerland? – a framework for a comprehensive assessment

2010 ◽  
Vol 27 ◽  
pp. 111-119 ◽  
Author(s):  
N. Köplin ◽  
D. Viviroli ◽  
B. Schädler ◽  
R. Weingartner
Keyword(s):  
Water Balance ◽  
Climate Models ◽  
Peak Flow ◽  
Regional Climate ◽  
Quantitative Information ◽  
Model Parameters ◽  
Flow Conditions ◽  
Ungauged Catchments ◽  
Entire Area ◽  
Alpine Catchments

Abstract. Within the framework of this study we identify mesoscale catchments in Switzerland that exhibit sensitivity towards a change in climate with a focus on alterations of the water balance and peak flow conditions. For this study, the hydrological modelling system PREVAH is used, which is a semi-distributed and conceptual yet process-oriented model forced with hourly meteorological input on basis of a spatial resolution of 500×500 m2. We calibrate the model where measured discharge records are available and transfer the calibrated model parameters to ungauged catchments through regionalisation, to arrive at a comprehensive set of model parameters for the entire area of Switzerland. To assess future changes, we apply an extensive set of 16 Regional Climate Models (RCMs) to the catchments. The RCM data are downscaled to a dense network of meteorological stations for the period from 2021 to 2050 using the Delta Change Approach. This downscaling method incorporates a bias correction of the RCM output and provides change rates and values for precipitation and temperature. In the present paper we describe the application of a calibration and regionalisation procedure developed previously for Northern Alpine catchments to Southern catchments. The necessity to differentiate between a Northern and a Southern Alpine region, with their distinct climatologic and physiogeographic features, has proved true as the calibrated parameter sets show systematic differences between those regions, e.g. for the runoff forming parameters percolation rate (PERC) or storage time for quick runoff (KOH). For the Southern Alpine area, we calibrated two thirds of the available catchments, i.e. 23 out of 36, successfully for standard and flood conditions according to a combined model score of a linear and logarithmic Nash-Sutcliffe-Efficiency (NSE, NSEln) and a mean annual volumetric deviation (VDa). The rate of successfully calibrated catchments is rather small in comparison with the results for the Northern Alpine catchments, where 140 out of 159 calibrations have been successful, and the distribution of the Southern catchments is more irregular. However, as the median NSE and NSEln as well as the range of VDa show an overall good model fit, a successful regionalisation may be expected. Next steps are the regionalisation of the Southern Alpine model parameters and the application of climate scenarios to the complete set of catchments, i.e. about 200 Swiss mesoscale catchments with an average area of 150 km2. Thus we can identify process-based relationships between climate sensitivity and catchment characteristics and provide quantitative information on future water balance and peak flow conditions of Swiss mesoscale catchments.

DWBmodelUN: an R-package for the hydrological model Dynamic Water Balance

2020 ◽  
Author(s):  
Camila García-Echeverri ◽  
Nicolás Duque-Gardeazabal ◽  
Carolina Vega-Viviescas ◽  
Pedro Arboleda-Obando ◽  
David Zamora
Keyword(s):  
Water Resources ◽  
Water Balance ◽  
Water Resources Management ◽  
Hydrological Model ◽  
R Package ◽  
Tropical Region ◽  
Model Parameters ◽  
Mountain Range ◽  
Time Step ◽  
Resources Management

<p>Evapotranspiration (ET) is one of the most important factors for the water budget and physical processes in the tropical region. This variable affects the atmospheric water and it is important for its capacity to control precipitation, including its influence on absorption and reflection of solar and terrestrial radiation. In the tropical context ET is a relevant process, where the condensation of large amounts of water vapor leads to the release of latent heat energy. In order to understand ecohydrological and climatic synergies and interactions in the tropical basins, different models have tried to represent the hydrological processes in time and space. But most of these models depend on variables that should be measured in situ and are rarely available or limited in the tropical countries. This inevitably requires the model to be simple enough and the parameters can be estimated from climate and basin characteristics. In this regard, Zhang et al. (2008) developed a hydrological model Dynamic Water Balance (DWB). DWB is a semi-distributed model supported in the Budyko framework, which uses partition curves to distribute water to a number of components based on water availability and demand concepts. In general, the model assumes the control over the water balance is mostly dominated by the precipitation (P) and potential evapotranspiration. </p><p>The hydrologic structure of DWB consists of two tanks, soil moisture store and groundwater store, and adjust its mathematical relations through the optimization of four parameters. Due to its simplicity and strong concepts, DWB had been implemented successfully in several types of basins around the globe (Rodriguez et al., 2019).</p><p>This work presents DWBmodelUN, a hydrological R-package with the implementation of DWB in a regular mesh at a monthly time step. DWBmodelUN contains 12 functions related to data entry pre-processing, mathematical development of DWB, calibration algorithm Dynamical Dimension Search and an interactive graphical  module. In overall terms, DWBmodelUN requires: (i) basin geographic data (defines the spatial resolution of the modelling), (ii) hydro-meteorological entry data (P, Temperatute, Streamflow) in raster format, (iii) initial values for the model parameters and (iv) setup data such as warm up, calibration and validation periods. </p><p>In addition, this package includes a practical example of application in Sogamoso River Basin, located at the Oriental mountain range of Colombia.  Therefore, data sets with hydrological, meteorological and setup information were incorporated within the package.</p><p>This tool intents to spread  the DWB model and facilitate its implementation in more basins. In this context, to execute DWBmodelUN users do not need extensive programming skills and the R-package was thought for easily adaptability.</p><p><strong>References</strong></p><p>Rodríguez, E., Sánchez, I., Duque, N., Arboleda, P., Vega, C., Zamora, D., … Burke, S. (2019). Combined Use of Local and Global Hydro Meteorological Data with Hydrological Models for Water Resources Management in the Magdalena - Cauca Macro Basin – Colombia. Water Resources Management. </p><p>Zhang, L., Potter, N., Hickel, K., Zhang, Y., & Shao, Q. (2008). Water balance modeling over variable time scales based on the Budyko framework – Model development and testing. Journal of Hydrology, 360(1–4), 117–131. </p>

scholarly journals Reconciling Simulated Moisture Fluxes Resulting from Alternate Hydrologic Model Time Steps and Energy Budget Closure Assumptions

2006 ◽  
Vol 7 (3) ◽  
pp. 355-370 ◽  
Author(s):  
Ingjerd Haddeland ◽  
Dennis P. Lettenmaier ◽  
Thomas Skaugen
Keyword(s):  
Energy Balance ◽  
Water Balance ◽  
Surface Temperature ◽  
Hydrologic Model ◽  
Model Parameters ◽  
Energy Balance Closure ◽  
Infiltration Capacity ◽  
Time Step ◽  
Effective Surface ◽  
Moisture Fluxes

Abstract Hydrological model predictions are sensitive to model forcings, input parameters, and the parameterizations of physical processes. Analyses performed for the Variable Infiltration Capacity model show that the resulting moisture fluxes are sensitive to the time step and energy balance closure assumptions. In addition, the model results are sensitive to the method of spatial and temporal disaggregation of precipitation. For parameter estimation purposes, it is desirable to do parameter searches in water balance mode (meaning that the effective surface temperature is assumed equal to the surface air temperature; hence no iteration for energy balance closure is performed) at daily time steps. However, transferring these parameters directly to other model modes (e.g., energy balance, in which an iteration for effective surface temperature is performed, and/or different model time steps) results in changes in the simulated moisture fluxes. The simulated differences in moisture fluxes are mainly a result of the parameterization of evapotranspiration at different time steps and model modes. A simple scheme that calculates correction factors for some model parameters is developed. The scheme is used to match simulated moisture fluxes in hourly and 3-hourly energy balance mode to the daily water balance simulation results, and to match hourly energy balance runs using spatially and temporally disaggregated precipitation to 3-hourly energy balance runs using uniformly disaggregated precipitation. For both approaches, the corrected simulations match the baseline simulations quite closely, both over transects across much of the continental United States and for test applications in the Ohio and Arkansas–Red River basins.

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