scholarly journals Impact of urbanization on flood of Shigu creek in Dongguan city

2018 ◽  
Vol 379 ◽  
pp. 55-60
Author(s):  
Luying Pan ◽  
Yangbo Chen ◽  
Tao Zhang
Keyword(s):  
Hydrological Model ◽  
Peak Flow ◽  
Flood Mitigation ◽  
Distributed Hydrological Model ◽  
Small Watershed ◽  
Rapid Urbanization ◽  
Dongguan City ◽  
Physically Based ◽  
Impact Of Urbanization ◽  
The Impact

Abstract. Shigu creek is a highly urbanized small watershed in Dongguan City. Due to rapid urbanization, quick flood response has been observed, which posted great threat to the flood security of Dongguan City. To evaluate the impact of urbanization on the flood changes of Shigu creek is very important for the flood mitigation of Shigu creek, which will provide insight for flood planners and managers for if to build a larger flood mitigation system. In this paper, the Land cover/use changes of Shigu creek from 1987–2015 induced by urbanization was first extracted from a local database, then, the Liuxihe model, a physically based distributed hydrological model, is employed to simulate the flood processes impacted by urbanization. Precipitation of 3 storms was used for flood processes simulation. The results show that the runoff coefficient and peak flow have increased sharply.

scholarly journals Predicting floods in a large karst river basin by coupling PERSIANN-CCS QPEs with a physically based distributed hydrological model

2019 ◽  
Vol 23 (3) ◽  
pp. 1505-1532 ◽  
Author(s):  
Ji Li ◽  
Daoxian Yuan ◽  
Jiao Liu ◽  
Yongjun Jiang ◽  
Yangbo Chen ◽  
...  
Keyword(s):  
River Basin ◽  
Relative Error ◽  
Hydrological Model ◽  
Peak Flow ◽  
Coupled Model ◽  
Distributed Hydrological Model ◽  
Flood Simulation ◽  
Flood Prediction ◽  
Physically Based ◽  
Karst River

Abstract. In general, there are no long-term meteorological or hydrological data available for karst river basins. The lack of rainfall data is a great challenge that hinders the development of hydrological models. Quantitative precipitation estimates (QPEs) based on weather satellites offer a potential method by which rainfall data in karst areas could be obtained. Furthermore, coupling QPEs with a distributed hydrological model has the potential to improve the precision of flood predictions in large karst watersheds. Estimating precipitation from remotely sensed information using an artificial neural network-cloud classification system (PERSIANN-CCS) is a type of QPE technology based on satellites that has achieved broad research results worldwide. However, only a few studies on PERSIANN-CCS QPEs have occurred in large karst basins, and the accuracy is generally poor in terms of practical applications. This paper studied the feasibility of coupling a fully physically based distributed hydrological model, i.e., the Liuxihe model, with PERSIANN-CCS QPEs for predicting floods in a large river basin, i.e., the Liujiang karst river basin, which has a watershed area of 58 270 km2, in southern China. The model structure and function require further refinement to suit the karst basins. For instance, the sub-basins in this paper are divided into many karst hydrology response units (KHRUs) to ensure that the model structure is adequately refined for karst areas. In addition, the convergence of the underground runoff calculation method within the original Liuxihe model is changed to suit the karst water-bearing media, and the Muskingum routing method is used in the model to calculate the underground runoff in this study. Additionally, the epikarst zone, as a distinctive structure of the KHRU, is carefully considered in the model. The result of the QPEs shows that compared with the observed precipitation measured by a rain gauge, the distribution of precipitation predicted by the PERSIANN-CCS QPEs was very similar. However, the quantity of precipitation predicted by the PERSIANN-CCS QPEs was smaller. A post-processing method is proposed to revise the products of the PERSIANN-CCS QPEs. The karst flood simulation results show that coupling the post-processed PERSIANN-CCS QPEs with the Liuxihe model has a better performance relative to the result based on the initial PERSIANN-CCS QPEs. Moreover, the performance of the coupled model largely improves with parameter re-optimization via the post-processed PERSIANN-CCS QPEs. The average values of the six evaluation indices change as follows: the Nash–Sutcliffe coefficient increases by 14 %, the correlation coefficient increases by 15 %, the process relative error decreases by 8 %, the peak flow relative error decreases by 18 %, the water balance coefficient increases by 8 %, and the peak flow time error displays a 5 h decrease. Among these parameters, the peak flow relative error shows the greatest improvement; thus, these parameters are of the greatest concern for flood prediction. The rational flood simulation results from the coupled model provide a great practical application prospect for flood prediction in large karst river basins.

scholarly journals State updating of a distributed hydrological model with Ensemble Kalman Filtering: effects of updating frequency and observation network density on forecast accuracy

2012 ◽  
Vol 16 (9) ◽  
pp. 3435-3449 ◽  
Author(s):  
O. Rakovec ◽  
A. H. Weerts ◽  
P. Hazenberg ◽  
P. J. J. F. Torfs ◽  
R. Uijlenhoet
Keyword(s):  
Hydrological Model ◽  
Forecast Accuracy ◽  
Markov Property ◽  
Distributed Hydrological Model ◽  
Time Step ◽  
Observation Network ◽  
Physically Based ◽  
Spatially Distributed ◽  
Observation Uncertainty ◽  
The Impact

Abstract. This paper presents a study on the optimal setup for discharge assimilation within a spatially distributed hydrological model. The Ensemble Kalman filter (EnKF) is employed to update the grid-based distributed states of such an hourly spatially distributed version of the HBV-96 model. By using a physically based model for the routing, the time delay and attenuation are modelled more realistically. The discharge and states at a given time step are assumed to be dependent on the previous time step only (Markov property). Synthetic and real world experiments are carried out for the Upper Ourthe (1600 km2), a relatively quickly responding catchment in the Belgian Ardennes. We assess the impact on the forecasted discharge of (1) various sets of the spatially distributed discharge gauges and (2) the filtering frequency. The results show that the hydrological forecast at the catchment outlet is improved by assimilating interior gauges. This augmentation of the observation vector improves the forecast more than increasing the updating frequency. In terms of the model states, the EnKF procedure is found to mainly change the pdfs of the two routing model storages, even when the uncertainty in the discharge simulations is smaller than the defined observation uncertainty.

Evaluation of a Distributed Hydrological Model for the Guishui River Basin

2013 ◽  
Vol 353-356 ◽  
pp. 2511-2514
Author(s):  
Jing Zhang ◽  
Zhen Zheng ◽  
Hui Li Gong
Keyword(s):  
River Basin ◽  
Surface Runoff ◽  
Hydrological Model ◽  
Scientific Basis ◽  
Scale Model ◽  
Distributed Hydrological Model ◽  
Mike She ◽  
Structural Principle ◽  
Physically Based ◽  
The Impact

At present, the application of various hydrological model provides scientific basis for the realization of the water resources management. MIKE SHE model is a classic physically-based watershed-scale model with great advantages in the coupling of surface water and ground water. In the paper, the development history and the present study situation of the distributed hydrological model MIKE SHE and the structural principle of the model is summarized. Furthermore, the ability and applicability of MIKE SHE model was preliminary evaluated for simulating surface runoff in the Guishui river basin in Beijing, China. The impact of different land use practices (the year of 1980 and 2005) on the hydrological response of the selected basin was initially assessed. Overall, the model was able to simulate surface runoff reasonably on annual intervals, representing all the hydrological components adequately.

scholarly journals Inverse distributed hydrological modelling of Alpine catchments

2006 ◽  
Vol 10 (3) ◽  
pp. 395-412 ◽  
Author(s):  
H. Kunstmann ◽  
J. Krause ◽  
S. Mayr
Keyword(s):  
Parameter Estimation ◽  
Hydrological Model ◽  
Model Performance ◽  
Horizontal Resolution ◽  
Nonlinear Parameter ◽  
Model Complexity ◽  
Distributed Hydrological Model ◽  
Nonlinear Parameter Estimation ◽  
Estimated Parameters ◽  
Physically Based

Abstract. Even in physically based distributed hydrological models, various remaining parameters must be estimated for each sub-catchment. This can involve tremendous effort, especially when the number of sub-catchments is large and the applied hydrological model is computationally expensive. Automatic parameter estimation tools can significantly facilitate the calibration process. Hence, we combined the nonlinear parameter estimation tool PEST with the distributed hydrological model WaSiM. PEST is based on the Gauss-Marquardt-Levenberg method, a gradient-based nonlinear parameter estimation algorithm. WaSiM is a fully distributed hydrological model using physically based algorithms for most of the process descriptions. WaSiM was applied to the alpine/prealpine Ammer River catchment (southern Germany, 710 km2 in a 100×100 m2 horizontal resolution. The catchment is heterogeneous in terms of geology, pedology and land use and shows a complex orography (the difference of elevation is around 1600 m). Using the developed PEST-WaSiM interface, the hydrological model was calibrated by comparing simulated and observed runoff at eight gauges for the hydrologic year 1997 and validated for the hydrologic year 1993. For each sub-catchment four parameters had to be calibrated: the recession constants of direct runoff and interflow, the drainage density, and the hydraulic conductivity of the uppermost aquifer. Additionally, five snowmelt specific parameters were adjusted for the entire catchment. Altogether, 37 parameters had to be calibrated. Additional a priori information (e.g. from flood hydrograph analysis) narrowed the parameter space of the solutions and improved the non-uniqueness of the fitted values. A reasonable quality of fit was achieved. Discrepancies between modelled and observed runoff were also due to the small number of meteorological stations and corresponding interpolation artefacts in the orographically complex terrain. Application of a 2-dimensional numerical groundwater model partly yielded a slight decrease of overall model performance when compared to a simple conceptual groundwater approach. Increased model complexity therefore did not yield in general increased model performance. A detailed covariance analysis was performed allowing to derive confidence bounds for all estimated parameters. The correlation between the estimated parameters was in most cases negligible, showing that parameters were estimated independently from each other.

scholarly journals The impact of urbanization expansion on agricultural land in Ethiopia: A review

2020 ◽  
Vol 8 (4) ◽  
pp. 73-80
Author(s):  
Assefa Ayele ◽  
Kassa Tarekegn
Keyword(s):  
Urban Areas ◽  
Agricultural Land ◽  
Urban Expansion ◽  
Rural Livelihoods ◽  
Vital Role ◽  
Rapid Urbanization ◽  
Economic Resource ◽  
House Construction ◽  
Impact Of Urbanization ◽  
The Impact

AbstractIn a country like Ethiopia where the vast majority of the populations are employed in agriculture, land is an important economic resource for the development of rural livelihoods. Agricultural land in peri-urban areas is, however, transformed into built-up regions through horizontal urban expansion that has an effect on land use value. In recent years Ethiopia has been experiencing rapid urbanization, which has led to an ever-increasing demand for land in peri-urban areas for housing and other nonagricultural activities that pervades agricultural land. There is a high demand for informal and illegal peri-urban land which has been held by peri-urban farmers, and this plays a vital role in the unauthorized and sub-standard house construction on agricultural land. This urbanization has not been extensively reviewed and documented. In this review an attempt has been made to assess the impacts of rapid urbanization on agricultural activities. Urban expansion has reduced the areas available for agriculture, which has seriously impacted upon peri-urban farmers that are often left with little or no land to cultivate and which has increased their vulnerability. Housing encroachments have been observed to be uncontrolled due to a weak government response to the trend of unplanned city expansion. This has left peri-urban farmers exposed to the negative shocks of urbanization because significant urbanization-related agricultural land loss has a positive correlation with grain production decrease. Appropriate governing bodies should control urban development in order to control the illegal and informal spread of urbanization on agricultural land that threatens food production.

The Dying Water Heritage of Sarkhej Roza

2019 ◽  
Vol 4 (2) ◽  
pp. 141-159
Author(s):  
Gargi Mishra ◽  
Prasenjit Shukla ◽  
Mona Iyer
Keyword(s):  
Fifteenth Century ◽  
Disposal Site ◽  
Archaeological Survey ◽  
Rapid Urbanization ◽  
The Past ◽  
National Importance ◽  
Heritage Site ◽  
Late Twentieth ◽  
Impact Of Urbanization ◽  
The Impact

Sarkhej Roza, a fifteenth century complex comprising of the mausoleum, mosque and cascade of natural and man-made lakes, and located in peri-urban Ahmedabad, Gujarat, India, is presently a heritage site of national importance under the Archaeological Survey of India (ASI). Originally, the Sarkhej lake was excavated to serve the religious purpose of ablution, recreation and climate conditioning that were quite functional until the late twentieth century before rapid urbanization in the catchment of its adjacent interconnected feeder Makarba lake took place. Unfettered development in the past two decades has encroached the common catchment of Makarba–Sarkhej lake cascade by almost 50 per cent. The then perennial sacred Sarkhej lake is now a drying sewage disposal site. Sarkhej Roza has received considerable attention for conserving built heritage aesthetically in the past. Since it is the duty of all stakeholders including ASI, Ahmedabad Municipal Corporation, Sarkhej Roza Committee, civil society and communities to work in harmony towards sustaining their natural heritage, this research has undertaken detailed site and stakeholder assessment to understand challenges faced by the lake and its precincts, and derived learnings from the stakeholder’s perspectives on the impact of urbanization on this water heritage. This was done in order to chart out the possibilities of reviving the Markarba–Sarkhej lake cascade before it is too late.

scholarly journals Evaluation of global fine-resolution precipitation products and their uncertainty quantification in ensemble discharge simulations

2016 ◽  
Vol 20 (2) ◽  
pp. 903-920 ◽  
Author(s):  
W. Qi ◽  
C. Zhang ◽  
G. Fu ◽  
C. Sweetapple ◽  
H. Zhou
Keyword(s):  
Hydrological Model ◽  
Tropical Rainfall Measuring Mission ◽  
Heavy Precipitation ◽  
Hydrological Models ◽  
Distributed Hydrological Model ◽  
Precipitation Product ◽  
Physically Based ◽  
Precipitation Estimation ◽  
Discharge Simulation ◽  
Fine Resolution

Abstract. The applicability of six fine-resolution precipitation products, including precipitation radar, infrared, microwave and gauge-based products, using different precipitation computation recipes, is evaluated using statistical and hydrological methods in northeastern China. In addition, a framework quantifying uncertainty contributions of precipitation products, hydrological models, and their interactions to uncertainties in ensemble discharges is proposed. The investigated precipitation products are Tropical Rainfall Measuring Mission (TRMM) products (TRMM3B42 and TRMM3B42RT), Global Land Data Assimilation System (GLDAS)/Noah, Asian Precipitation – Highly-Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN), and a Global Satellite Mapping of Precipitation (GSMAP-MVK+) product. Two hydrological models of different complexities, i.e. a water and energy budget-based distributed hydrological model and a physically based semi-distributed hydrological model, are employed to investigate the influence of hydrological models on simulated discharges. Results show APHRODITE has high accuracy at a monthly scale compared with other products, and GSMAP-MVK+ shows huge advantage and is better than TRMM3B42 in relative bias (RB), Nash–Sutcliffe coefficient of efficiency (NSE), root mean square error (RMSE), correlation coefficient (CC), false alarm ratio, and critical success index. These findings could be very useful for validation, refinement, and future development of satellite-based products (e.g. NASA Global Precipitation Measurement). Although large uncertainty exists in heavy precipitation, hydrological models contribute most of the uncertainty in extreme discharges. Interactions between precipitation products and hydrological models can have the similar magnitude of contribution to discharge uncertainty as the hydrological models. A better precipitation product does not guarantee a better discharge simulation because of interactions. It is also found that a good discharge simulation depends on a good coalition of a hydrological model and a precipitation product, suggesting that, although the satellite-based precipitation products are not as accurate as the gauge-based products, they could have better performance in discharge simulations when appropriately combined with hydrological models. This information is revealed for the first time and very beneficial for precipitation product applications.

THE IMPACT OF URBANIZATION ON MURDER RATES AND ON THE GEOGRAPHY OF HOMICIDE IN ENGLAND AND WALES, 1780–1850

2010 ◽  
Vol 53 (3) ◽  
pp. 671-698 ◽  
Author(s):  
PETER KING
Keyword(s):  
Rural Areas ◽  
Rapid Urbanization ◽  
Homicide Rates ◽  
England And Wales ◽  
Large Cities ◽  
Methodological Problems ◽  
Urban And Rural Areas ◽  
And Migration ◽  
Impact Of Urbanization ◽  
The Impact

ABSTRACTAlthough higher murder rates have traditionally been associated with large cities, this view has recently been challenged by several historians who have argued that ‘homicide rates were negatively correlated with urbanisation and industrialisation’, and this is rapidly becoming the new consensus. By exploring the geography of homicide rates for one area undergoing rapid urbanization and industrialization – England and Wales, 1780–1850 – this article challenges this new view and re-assesses the relationship between recorded homicide rates and both modernization and urbanization. After discussing the methodological problems involved in using homicide statistics, it focuses mainly on the first fifteen years for which detailed county-based data is available – 1834–48 – as well as looking at the more limited late eighteenth-century and early nineteenth-century evidence. This data raises fundamental questions about the links historians have recently made between urbanization and low homicide rates, since the remote rural parts of England and Wales generally had very low recorded murder rates while industrializing and rapidly urbanizing areas such as Lancashire had very high ones. Potential explanations for these systematic and large variations between urban and rural areas – including the impact of age structures and migration patterns – are then explored.

scholarly journals Assessing the hydrologic restoration of an urbanized area via integrated distributed hydrological model

2013 ◽  
Vol 10 (4) ◽  
pp. 4099-4132 ◽  
Author(s):  
D. H. Trinh ◽  
T. F. M. Chui
Keyword(s):  
Urban Areas ◽  
Hydrological Model ◽  
Peak Flow ◽  
Green Roofs ◽  
Base Flow ◽  
Peak Discharge ◽  
Generic Model ◽  
Distributed Hydrological Model ◽  
Hydrologic Restoration ◽  
The Tropics

Abstract. Green structures (e.g. green roof and bio-retention systems) are adopted to mitigate the hydrological impacts of urbanization. However, our current understanding of the urbanization impacts are often process-specific (e.g. peak flow or storm recession), and our characterizations of green structures are often on a local scale. This study uses an integrated distributed hydrological model, Mike SHE, to evaluate the urbanization impacts on both overall water balance and water regime, and also the effectiveness of green structures at a catchment level. Three simulations are carried out for a highly urbanized catchment in the tropics, representing pre-urbanized, urbanized and restored conditions. Urbanization transforms vegetated areas into impervious surfaces, resulting in 20 and 66% reductions in infiltration and base flow respectively, and 60 to 100% increase in peak outlet discharge. Green roofs delay the peak outlet discharge by 2 h and reduce the magnitude by 50%. Bio-retention systems mitigate the peak discharge by 50% and also enhance infiltration by 30%. The combination of green roofs and bio-retention systems even reduces the peak discharge to the pre-urbanized level. The simulation results obtained are independent of field data, enabling a generic model for understanding hydrological changes during the different phases of urbanization. This will benefit catchment level planning of green structures in other urban areas.

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