Regionalization of Reservoir regulation parameters using physiographic and climatological predictors

2021 ◽  
Author(s):  
Pallav Kumar Shrestha ◽  
Stephan Thober ◽  
Luis Samaniego
Keyword(s):  
Water Level ◽  
Catchment Area ◽  
Hydrological Modeling ◽  
Transfer Functions ◽  
Global Scale ◽  
Rule Curves ◽  
Reservoir Regulation ◽  
Reservoir Parameter ◽  
Mathematical Relationships ◽  
Upstream Catchment

<p>Present regional and global scale hydrology has to account for man-made reservoirs that impart significant regulation signature into the downstream streamflow regime. Optimization of domains with large number of reservoirs would incur multitude of reservoir regulation parameters. Such parameter-set-per-reservoir approach not only results in excessive computational costs but also, by principle, lacks effective constraining of the parameter space. We propose an approach to derive single set of parameters for all the reservoirs and lakes in the modelling domain. The hypothesis is that reservoir regulation parameters can be regionalized using physiography and climatology at lakes and their catchments.<br><br>To test this hypothesis, we setup a modeling domain for the São Francisco basin of Northeast Brazil in the mesoscale hydrological model (mHM, www.ufz.de/mhm). The domain consists of climatology ranging from tropical (As) to semi-arid (BSh) and reservoirs with catchment area varying from less than 500 km<sup>2</sup> to greater than 500,000 km<sup>2</sup>. We carried out correlation analysis between selected physiographical and climatological predictors and the reservoir parameters of the multiscale lake module, mLM, of the mHM model (https://presentations.copernicus.org/EGU2020/EGU2020-6047_presentation.pdf). For an instance, the reservoir rule curves in mLM are estimated based on inflow and position of water level. The predictors here are inflow and water level which are normalized using catchment area and the shape of the reservoir, respectively. Similarly, the timing and shape parameters of rule curves were plotted against the climatological characteristics of the upstream catchment. The preliminary results reveal significant trends between the mLM parameters and the normalized predictors. These mathematical relationships, better known as transfer functions, can now be used to generate a single global reservoir parameter set.</p><p>The demonstrated hypothesis helps to optimize regulated hydrology using a single parameter set, irrespective of size, location and inherent climatology of reservoirs involved. This is inline with the pre-existing paradigm of multiscale parameter regionalization (MPR) of mHM. The findings contribute to the contemporary effort of hydrological modeling society towards improved global scale hydrological modeling.</p>

Using Sliding Mode Control to Adjust Drum Level of a Boiler Unit With Time Varying Parameters

2010 ◽  
Author(s):  
Hamed Moradi ◽  
Firooz Bakhtiari-Nejad ◽  
Majid Saffar-Avval ◽  
Aria Alasty
Keyword(s):  
Water Level ◽  
Transfer Functions ◽  
Sliding Mode ◽  
Operating Conditions ◽  
Model Parameters ◽  
Feed Water ◽  
Time Varying ◽  
Boiler Unit ◽  
Varying Parameters ◽  
Time Varying Parameters

Stable control of water level of drum is of great importance for economic operation of power plant steam generator systems. In this paper, a linear model of the boiler unit with time varying parameters is used for simulation. Two transfer functions between drum water level (output variable) and feed-water and steam mass rates (input variables) are considered. Variation of model parameters may be arisen from disturbances affecting water level of drum, model uncertainties and parameter mismatch due to the variant operating conditions. To achieve a perfect tracking of the desired drum water level, two sliding mode controllers are designed separately. Results show that the designed controllers result in bounded values of control signals, satisfying the actuators constraints.

scholarly journals Supplementary material to "Global-scale evaluation of 23 precipitation datasets using gauge observations and hydrological modeling"

2017 ◽  
Author(s):  
Hylke E. Beck ◽  
Noemi Vergopolan ◽  
Ming Pan ◽  
Vincenzo Levizzani ◽  
Albert I. J. M. van Dijk ◽  
...  
Keyword(s):  
Hydrological Modeling ◽  
Global Scale ◽  
Scale Evaluation ◽  
Supplementary Material

scholarly journals The Exact Groundwater Divide on Water Table between Two Rivers: A Fundamental Model Investigation

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 685 ◽  
Author(s):  
Peng-Fei Han ◽  
Xu-Sheng Wang ◽  
Li Wan ◽  
Xiao-Wei Jiang ◽  
Fu-Sheng Hu
Keyword(s):  
Water Level ◽  
Water Table ◽  
Catchment Area ◽  
River Basins ◽  
Two Dimensional ◽  
Local Flow ◽  
Fundamental Model ◽  
Through Flow ◽  
Flow Systems ◽  
Pass Through

The groundwater divide within a plane has long been delineated as a water table ridge composed of the local top points of a water table. This definition has not been examined well for river basins. We developed a fundamental model of a two-dimensional unsaturated–saturated flow in a profile between two rivers. The exact groundwater divide can be identified from the boundary between two local flow systems and compared with the top of a water table. It is closer to the river of a higher water level than the top of a water table. The catchment area would be overestimated (up to ~50%) for a high river and underestimated (up to ~15%) for a low river by using the top of the water table. Furthermore, a pass-through flow from one river to another would be developed below two local flow systems when the groundwater divide is significantly close to a high river.

scholarly journals Significant uncertainty in global scale hydrological modeling from precipitation data errors

2015 ◽  
Vol 529 ◽  
pp. 1095-1115 ◽  
Author(s):  
Frederiek C. Sperna Weiland ◽  
Jasper A. Vrugt ◽  
Rens (L.) P.H. van Beek ◽  
Albrecht H. Weerts ◽  
Marc F.P. Bierkens
Keyword(s):  
Hydrological Modeling ◽  
Global Scale ◽  
Precipitation Data ◽  
Data Errors

scholarly journals Hydrological Characteristics of Kaligarang Watershed

2004 ◽  
Vol 14 (1) ◽  
Author(s):  
Soewarno Soewarno ◽  
Srimulat Yuningsih
Keyword(s):  
Return Period ◽  
Catchment Area ◽  
Water Volume ◽  
Runoff Coefficient ◽  
Central Java ◽  
Flood Discharge ◽  
Yearly Average ◽  
Time Of Travel ◽  
Upstream Catchment ◽  
Rising Time

This paper is a result of research concerning hydrological characteristic in the Garang Catchment Area. At present tha catchment area is often facing the problem of flooding in the dense populated area with cause a lot of loos in Semarang City. This research is aimed at studying hydrological harateristic in the Garang Catchment Area. Hydrological data are obtain from direct measurement at the stream gauging stations in the Garang Catchment Area and collected from Balai Hidrologi Office at Pusat Litbang Teknologi Sumber Daya Air in Bandung and from Hydrological Unit of Central Java Province. From this research were known the rainfall depth, their distribution and their return period; runoff coefficient; streamflow volume; dependable flow; flood discharge characteristi; and minimum discharge. From the some occuring flood indicates of the runoff coefficient is about 0.70. The water volume wasted to the sea is about 195 million m3/year. Yearly average of the dependable flow at stream gaunging stations: Garang – Pajangan  is about 2.28 m3/sec; Garang – Patemon is about 0.92 m3/sec and Kreo – Pancur is about 1.26 m3/sec. Yearly mean of annual flood discharge at Garang – Pajangan is about 435 m3/sec. The maximum capacity of river channel is about 485 m3/sec. The flood discharge characteristic are as follows: time of travel of flood is generally one km/hour approximately, rising time is about 3 hours and time of recession is about 6 – 11 hours. The floods, they are generally occur at the night. Flush flood of 1022 m3/sec occured on January 26, 1990 is estimated on 50 year return period, with 15 year return period of rainfall. The range of minimum discharge is about 0.43 – 3.15 m3/sec. The maximum discharge is about 47.2 – 1118 times of the minimum discharge. Design of the dam in Kreo River at Jatibarang and Kripik River at Mundingan, also increasing of the reforestation area in the upstream catchment are an alternative to reduce the Garang River peak flood.

scholarly journals Value of river discharge data for global-scale hydrological modeling

2007 ◽  
Vol 4 (6) ◽  
pp. 4125-4173 ◽  
Author(s):  
M. Hunger ◽  
P. Döll
Keyword(s):  
Correction Factor ◽  
River Discharge ◽  
Hydrological Modeling ◽  
Model Performance ◽  
Flow Characteristics ◽  
Global Scale ◽  
The Other ◽  
Station Correction ◽  
Discharge Data

Abstract. This paper investigates the value of observed river discharge data for global-scale hydrological modeling of a number of flow characteristics that are required for assessing water resources, flood risk and habitat alteration of aqueous ecosystems. An improved version of WGHM (WaterGAP Global Hydrology Model) was tuned in a way that simulated and observed long-term average river discharges at each station become equal, using either the 724-station dataset (V1) against which former model versions were tuned or a new dataset (V2) of 1235 stations and often longer time series. WGHM is tuned by adjusting one model parameter (γ) that affects runoff generation from land areas, and, where necessary, by applying one or two correction factors, which correct the total runoff in a sub-basin (areal correction factor) or the discharge at the station (station correction factor). The study results are as follows. (1) Comparing V2 to V1, the global land area covered by tuning basins increases by 5%, while the area where the model can be tuned by only adjusting γ increases by 8% (546 vs. 384 stations). However, the area where a station correction factor (and not only an areal correction factor) has to be applied more than doubles (389 vs. 93 basins), which is a strong drawback as use of a station correction factor makes discharge discontinuous at the gauge and inconsistent with runoff in the basin. (2) The value of additional discharge information for representing the spatial distribution of long-term average discharge (and thus renewable water resources) with WGHM is high, particularly for river basins outside of the V1 tuning area and for basins where the average sub-basin area has decreased by at least 50% in V2 as compared to V1. For these basins, simulated long-term average discharge would differ from the observed one by a factor of, on average, 1.8 and 1.3, respectively, if the additional discharge information were not used for tuning. The value tends to be higher in semi-arid and snow-dominated regions where hydrological models are less reliable than in humid areas. The deviation of the other simulated flow characteristics (e.g. low flow, inter-annual variability and seasonality) from the observed values also decreases significantly, but this is mainly due to the better representation of average discharge but not of variability. (3) The optimal sub-basin size for tuning depends on the modeling purpose. On the one hand, small basins between 9000 and 20 000 km2 show a much stronger improvement in model performance due to tuning than the larger basins, which is related to the lower model performance (with and without tuning), with basins over 60 000 km2 performing best. On the other hand, tuning of small basins decreases model consistency, as almost half of them require a station correction factor.

scholarly journals A framework to regionalize conceptual model parameters for global hydrological modeling

2020 ◽  
Author(s):  
Wenyan Qi ◽  
Jie Chen ◽  
Lu Li ◽  
Chong-yu Xu ◽  
Jingjing Li ◽  
...  
Keyword(s):  
Water Resources ◽  
Conceptual Model ◽  
Hydrological Modeling ◽  
Global Scale ◽  
Spatial Proximity ◽  
Model Parameters ◽  
Hydrological Models ◽  
Physical Similarity ◽  
Similarity Method ◽  
Global Water

Abstract. To provide an accurate estimate of global water resources and help to formulate water allocation policies, global hydrological models (GHMs) have been developed. However, it is difficult to obtain parameter values for GHMs, which results in large uncertainty in estimation of the global water balance components. In this study, a framework is developed for building GHMs based on parameter regionalization of catchment scale conceptual hydrological models. That is, using appropriate global scale regionalization scheme (GSRS) and conceptual hydrological models to simulate runoff at the grid scale globally and the Network Response Routing (NRF) method to converge the grid runoff to catchment streamflow. To achieve this, five regionalization methods (i.e. the global mean method, the spatial proximity method, the physical similarity method, the physical similarity method considering distance, and the regression method) are first tested for four conceptual hydrological models over thousands medium-sized catchments (2500–50000 km2) around the world to find the appropriate global scale regionalization scheme. The selected GSRS is then used to regionalize conceptual model parameters for global land grids with 0.5°×0.5° resolution on latitude and longitude. The results show that: (1) Spatial proximity method with the Inverse Distance Weighting (IDW) method and the output average option (SPI-OUT) offers the best regionalization solution, and the greatest gains of the SPI-OUT method were achieved with mean distance between the donor catchments and the target catchment is no more than 1500 km. (2) It was found the Kling-Gupta efficiency (KGE) value of 0.5 is a good threshold value to select donor catchments. And (3) Four different GHMs established based on framework were able to produce reliable streamflow simulations. Overall, the proposal framework can be used with any conceptual hydrological model for estimating global water resources, even though uncertainty exists in terms of using difference conceptual models.

scholarly journals Simulating river flow velocity on global scale

2005 ◽  
Vol 5 ◽  
pp. 133-136 ◽  
Author(s):  
K. Schulze ◽  
M. Hunger ◽  
P. Döll
Keyword(s):  
Flow Velocity ◽  
Cross Sections ◽  
Hydrological Modeling ◽  
River Flow ◽  
Simple Algorithm ◽  
Global Scale ◽  
Limited Information ◽  
Data Set ◽  
Measured Velocity ◽  
Test Flow

Abstract. Flow velocity in rivers has a major impact on residence time of water and thus on high and low water as well as on water quality. For global scale hydrological modeling only very limited information is available for simulating flow velocity. Based on the Manning-Strickler equation, a simple algorithm to model temporally and spatially variable flow velocity was developed with the objective of improving flow routing in the global hydrological model of WaterGAP. An extensive data set of flow velocity measurements in US rivers was used to test and to validate the algorithm before integrating it into WaterGAP. In this test, flow velocity was calculated based on measured discharge and compared to measured velocity. Results show that flow velocity can be modeled satisfactorily at selected river cross sections. It turned out that it is quite sensitive to river roughness, and the results can be optimized by tuning this parameter. After the validation of the approach, the tested flow velocity algorithm has been implemented into the WaterGAP model. A final validation of its effects on the model results is currently performed.

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