scholarly journals Spatial Rainfall Variability in Urban Environments—High-Density Precipitation Measurements on a City-Scale

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1157 ◽  
Author(s):  
Roman Maier ◽  
Gerald Krebs ◽  
Markus Pichler ◽  
Dirk Muschalla ◽  
Günter Gruber

Rainfall runoff models are frequently used for design processes for urban infrastructure. The most sensitive input for these models is precipitation data. Therefore, it is crucial to account for temporal and spatial variability of rainfall events as accurately as possible to avoid misleading simulation results. This paper aims to show the significant errors that can occur by using rainfall measurement resolutions in urban environments that are too coarse. We analyzed the spatial variability of rainfall events from two years with the validated data of 22 rain gauges spread out over an urban catchment of 125 km2. By looking at the interstation correlation of the rain gauges for different classes of rainfall intensities, we found that rainfall events with low and intermediate intensities show a good interstation correlation. However, the correlation drops significantly for heavy rainfall events suggesting higher spatial variability for more intense rainstorms. Further, we analyzed the possible deviation from the spatial rainfall interpolation that uses all available rain gauges when reducing the number of rain gauges to interpolate the spatial rainfall for 24 chosen events. With these analyses we found that reducing the available information by half results in deviations of up to 25% for events with return periods shorter than one year and 45% for events with longer return periods. Assuming uniformly distributed rainfall over the entire catchment resulted in deviations of up to 75% and 125%, respectively. These findings are supported by the work of past research projects and underline the necessity of a high spatial measurement density in order to account for spatial variability of intense rainstorms.

2020 ◽  
Author(s):  
Yangzi Qiu ◽  
Ioulia Tchiguirinskaia ◽  
Daniel Scherzter

<p>Nature-Based Solutions (NBS) practices provide many benefits for sustainable development of urban environments, one of which is their ability to mitigate the urban waterlogging. In many previous studies, the performances of NBS practices are analysed with the semi-distributed model and artificial rainfall without considering the spatial variability of rainfall. However, the NBS practices are decentralized in urban areas, their hydrological response is very depends on the small-scale heterogeneity of urban environments. Therefore, this research aims to investigate the impacts of small-scale rainfall variability on the hydrological responses of NBS practices.</p><p>In this study, the hydrological response of NBS practices was analysed at the urban catchment scale. A 5.2 km<sup>2</sup> semi-urban catchment (Guyancourt, located in the South-West of Paris) are investigated under various future NBS implementation scenarios (porous pavement, green roof, rain garden and combined). Regarding the objective of this research, three typical rainfall events are selected. Three sets of distributed rainfall data at a high resolution of 250 m×250 m×3.41 min were obtained from the X-band radar of Ecole des Ponts ParisTech (ENPC). In addition, three sets of corresponded homogeneous rainfall data are applied and used for comparing with the distributed one. Furthermore, a fully distributed and grid based hydrological model (Multi-Hydro), developed at ENPC, which takes into consideration the spatial variability of the whole catchment at 10 m scale. The hydrological response of NBS scenarios was analysed with the percentage error on total volume and peak discharge, with regards to the baseline scenario (current configuration).</p><p>Results show that the spatial variability of rainfall has the impact on the hydrological response of NBS scenarios in varying degrees, and it is more evident for green roof scenario. In three rainfall events, the maximum percentage error on peak discharge of green roof scenario under distributed rainfall is 23 %, while that of the green roof scenario under homogeneous rainfall is 17.7%. Overall, the results suggest that the implementation of porous pavement and rain garden is more flexible than implementation of green roof in a semi-urban catchment.</p>


Author(s):  
Romário Rosa de Sousa

LOW COST RAIN GAUGES AND RAINFALL VARIABILITY IN BARRA DO GARÇAS – MT (OCTOBER 2015 TO APRIL 2016)PLUVIÓMETRO DE BAJO COSTO Y LA VARIACIÓN DE LA LLUVIA EN EL MUNICIPIO DE BARRA DO GARÇAS – MT (OCTUBRE DE 2015 A ABRIL 2016)Este trabalho teve como objetivo principal confeccionar e distribuir vinte pluviômetros de baixo custo de PVC, dentro do município de Barra do Garças-MT, onde posteriormente a partir dos dados coletados, gerou-se um mapa pluviométrico da irregularidade da chuva. Os trabalhos metodológicos foram desenvolvidos em onze etapas distintas. Após toda a fase de aquisição dos materiais de baixo custo, na sequência realizou-se os seguintes procedimentos: confecção dos pluviômetros, aferição, instalação, treinamento dos produtores rurais, coleta de dados a campo, organização dos dados em planilha eletrônica com geração de relatório de tabela dinâmica, realização do processo de interpolação dos dados, geração do mapa pluviométrico, ajustes e finalização do mapa gerado, análise e discussão dos dados. É importante ressaltar que o processo de interpolação dos dados foi realizado no software ArcGis, 10.1. Ressalta-se que o processo de construção do pluviômetro de baixo custo, demonstrou que foi de grande ajuda, no sentido de baixar custos com um instrumento de grande importância para o meio rural e urbano. Também ficou comprovado que o pluviômetro de baixo custo, é um aparelho de credibilidade e confiabilidade nos registros dos dados pluviométricos. Quanto a distribuição pluviométrica da chuva no município de Barra do Garças-MT, foi bem diversificada e irregular para o período estudado, onde averiguou-se que o maior acumulo pluviométrico foi registrado no extremo sul do município com 986,1mm de chuva. E encontra partida um núcleo seco com um baixo volume de precipitação foi confirmado na porção leste com 146,2 mm de chuva.Palavras-chave: Pluviômetros; Chuva; PVC; Baixo Custo.ABSTRACTThis study aims to design, assemble and distribute twenty low cost PVC rain gauges in Barra do Garças-MT, where afterwards a rainfall map was generated from the collected data. The methodological works were developed in eleven distinct stages. Following the entire acquisition phase of the low cost materials, the following procedures were carried out: preparation of the rain gauges, gauging, installation, training of rural producers, data collection in the field, data organization in electronic spreadsheet making a dynamic table report, data interpolation, creating a rainfall map, adjustment and finalization of the created map, data analysis and discussion. It is important to note the data interpolation process was performed in ArcGis software, 10.1. It should be noted that the process of construction of the low cost rain gauge showed that it was of great help in order to reduce costs with an instrument of great importance for the rural and urban environments. It has also been proven that the low cost rain gauge is an apparatus of credibility and reliability in rainfall records. As for the rainfall distribution in Barra do Garças-MT, it was well diversified and irregular for the period studied, where it was verified that the highest rainfall accumulation was recorded in the southern end of the municipality with 986.1mm of rain. However, finding a dry core with a low volume of precipitation was confirmed in the eastern portion with 146.2mm of rain.Keywords: Rain Gauges; Rain; PVC; Low Cost.RESUMENEste trabajo tuvo como objetivo principal elaborar, montar y distribuir veinte pluviómetros de bajo costo de PVC, dentro del municipio de Barra do Garças-MT, posteriormente, a partir de los datos colectados, se originó un mapa pluviométrico de la irregularidad de la lluvia. Los trabajos metodológicos fueron desarrollados en once etapas distintas. Después de toda la fase de adquisición de los materiales de bajo costo, en seguida se realizaron los siguientes procedimientos: confección de los pluviómetros, calibración, instalación, entrenamiento de los productores rurales, colecta de datos a campo, organización de los datos en planilla electrónica con elaboración de un informe de tabla dinámica, realización del proceso de interpolación de los datos, producción del mapa pluviométrico, ajustes y finalización del mapa generado, análisis y discusión de los datos. Es importante realzar que el proceso de interpolación de los datos fueron realizados en el software ArcGis, 10.1. Se resalta que el proceso de construcción del pluviómetro de bajo costo, demostró que fue de gran ayuda, en el sentido de bajar costos con un instrumento de gran importancia para el medio rural y urbano. También quedó demostrado que el pluviómetro de bajo costo, es un aparato de credibilidad y confiabilidad en los registros de los datos pluviométricos. Cuanto a la distribución pluviométrica en el municipio de Barra do Garças-MT, fue bien diversificada e irregular para el periodo estudiado, donde se comprobó que el mayor acúmulo pluviométrico fue registrado en el extremo Sur del municipio con 986,1mm de lluvia. En contra partida un núcleo seco con un bajo volumen de precipitación fue confirmado en la región Este con 146,2 mm de lluvia.Palabras-clave: Pluviómetros; Lluvia; PVC; Bajo Costo.


2021 ◽  
Author(s):  
Luc Neppel ◽  
Pierre Marchand ◽  
Pascal Finaud-Guyot ◽  
Vincent Guinot ◽  
Christian Salles

<p>This study presents a new high density rain gauges network installed in urban area to study spatio-temporal structure and variability of precipitation at small scales. The preliminary results concerning gauges calibration and characterization of the rainfall spatial variability at fine scale are discussed.</p><p>In urban areas, the impervious surfaces connected to the drainage system leads to highly dynamic flows. The flood and runoff risk characterization requires  fine spatiotemporal scale to describe hydrological model input data :rainfall within spatial scale of less than 1km and temporal scale close to 1minis necessary for urban hydrological applications and risk assessment. In order to characterize small-scale rainfall spatiotemporal variability, a dense rain gauges network is deployed at Montpellier (France) with inter-gauges distances from 100m to 1km. Currently, 9 tipping bucket rain gauges  associated with 9 anemometers are acquiring rainfall and wind norm intensity every minutes. The network density and extension will be increased soon.</p><p>The first year measurements highlight a spatial variability of the 1-minute rainfall at the subkilometer scale. This observed variability is analyzed in view of the measurement uncertainty (gauge calibration, gauge error, bias due to the gauge location) to identify the natural rainfall variability.</p><p>This contribution presents the new densely extensive rainfall  network measurement, the typing bucket raingauge calibration and highlights that the observed 1-minute rainfall intensity variability  is significant and cannot be only explained by the measurement uncertainties.</p>


2018 ◽  
Vol 50 (1) ◽  
pp. 60-74 ◽  
Author(s):  
Jiaqing Liu ◽  
Wenjie Liu ◽  
Weixia Li ◽  
Huanhuan Zeng

Abstract In Xishuangbanna, southwest China, the large-scale monoculture rubber plantation replaced the primary tropical forest, which changed the regional hydrology processes and biogeochemical cycles. As throughfall was an important component of the forest ecosystem water input, we researched the spatial variability and temporal stability of throughfall in the rubber plantation. We recorded 30 rainfall events by using 90 rain gauges during 2015–2016. We found a highly significant linear relationship between rainfall and throughfall, and a strong power correlation between the peak 30 min rainfall intensity and throughfall. The coefficient of variation for throughfall was significant and negatively correlated with rainfall and rainfall intensity. We also observed that throughfall had a strong spatial autocorrelation that would decrease during heavy rainfall events. The results indicate that the leaf area index did not have a significant relationship with throughfall. However, the lateral translocation of the throughfall in the canopy significantly affected the spatial distribution of the throughfall. Generally, the lower throughfall positions were close to the nearest rubber trunk, and the higher throughfall positions were mostly below the slope. This study contributes to the knowledge of the spatiotemporal heterogeneity of throughfall and helps elucidate the interception processes in the rubber plantation.


1995 ◽  
Vol 32 (1) ◽  
pp. 225-232 ◽  
Author(s):  
A. Saget ◽  
G. Chebbo ◽  
M. Desbordes

To treat urban wet weather discharges, storage tanks seem to be efficient tools. Using 17 French catchments with an average of one year of measurements, we have estimated the volumes required, at the outlet of the catchments and at the inlet of a tank, to intercept the suspended solids load discharged during several months and during the most polluted events. The results vary widely from one basin to another, between 30 and 150 m3/active ha to intercept 80% of the annual suspended solids load. This does not allow us to draw conclusions about the volumes required in an average situation because rainfall depths and return periods of the rainfall events are different between the catchments. These factors seem to have a big influence on the interception efficiency of the storage tanks. The results can only be seen as representative of the year during which the measurements were taken.


1998 ◽  
Vol 37 (11) ◽  
pp. 97-104
Author(s):  
L. Neppel ◽  
M. Desbordes ◽  
J. M. Masson

When large periods of observation are considered, the densest information are often a collection of the daily rain gauges network. As this information is scattered in space, the stochastic results and specially the rainfall risk assessment, are biased because of the rainfall events that are not ‘observed’ by the network. Rainfall risk can be assessed using a punctual approach with the estimation of regional return period of a punctual rainfall depth exceeding a given value, or using a spatial approach with the frequency analysis of the areas of isohyets defined at a given rain threshold τ. This last approach consists, for a given τ, in estimating the return period of isohyet areas. Using simulation, a method of unbiased rainfall risk assessment is proposed for the Languedoc-Roussillon region (France). It has been shown that the bias influence is negligible for the regional return periods of isohyet areas, for 24-hour and 48-hour duration, when compared to their confident limits. On the contrary the return periods of punctual rainfall depths above a given value are more sensitive: for values above 170 mm/24h and 270 mm/48h, the biased return periods could be up to 3 times overestimated.


2020 ◽  
Author(s):  
Clara Hohmann ◽  
Gottfried Kirchengast ◽  
Sungmin O ◽  
Wolfgang Rieger ◽  
Ulrich Foelsche

Abstract. Precipitation is a key input to hydrological models. While rain gauges provide the most direct precipitation measurements, their accuracy in capturing rain patterns highly depends on the spatial variability of rainfall events and the gauge network density. In this study, we employ a high-resolution meteorological station network (mean station distance of 1.4 km), the WegenerNet in southeastern Austria, to investigate the impact of station density and interpolation schemes on runoff simulations. We first simulate runoff during heavy precipitation (three short-duration and three long-duration events) using a physically based hydrological model with precipitation input obtained from a full network of 158 stations. The same simulations are then repeated with precipitation inputs from subnetworks of 5, 8, 16, 32, and 64 stations, using three different interpolation schemes – Inverse Distance Weighting with a weighting power of 2 and of 3, respectively, and Thiessen polygon interpolation. We find that the performance of runoff simulations is greatly influenced by the spatial variability of precipitation input, especially for short-duration rainfall events and in small catchments. For long-duration events, reliable runoff simulations in the study area can be obtained with a subnetwork of 16 or more well-distributed gauges (mean station distance of about 6 km). We find a clear effect of interpolation schemes on runoff modeling as well, but only for low-density gauge networks. The sensitivity to the precipitation input is smaller for long-duration heavy precipitation events and bigger catchments. As a next step we suggest to study an ensemble of precipitation datasets in combination with runoff modeling to be able to decompose the effects of precipitation measurement uncertainties and its spatial variability.


Sign in / Sign up

Export Citation Format

Share Document