Surface Runoff Management Model of Bandung Regency Through Remote Sensing Analysis

Flood is caused by surface runoff, therefore controlling the surface runoff is necessary especially on built areas. The aim of this research is to analyze the width, calculating the volume of surface runoff and analyze the model of infiltration wells on built areas in Bandung Regency. The methods implemented in this research is experimental method. This method was carried while analyzing rainfall on built areas samples, which is house building. The land use was analyzed through Landsat 8 imagery in the year of 2019. Rainfall volume was calculated by equation V = h x l. Meanwhile the volume of infiltration well was calculated by equation V = h x k. The result of 2019 Landsat imagery analysis shows that 19.01% of total watersheds in Bandung Regency or as much as 1382.13 km2 is the built areas. The highest rainfall in total of 0.02431 m occurred in October on the area of 197.67 m2 and became a surface runoff of 377,534 m3. In a house building, as built area example, as wide as 90 m3, the amount of 2.19 m3 rainwater needed to be infiltrated. Infiltration well model is a management model on each built areas, so that rainwater on built areas would not be turned into a surface runoff.

Soybean Productivity and Agrometeorological Variables Assessed from the perspective of Spatial and Circular Statistics

Climate change can affect the development of soybean cultivation, impacting your productivity. Thus, agrometeorological information is essential in order to improve productivity strategies. The objective of the paper was to analyze the influence and occurrence of seasonality of the following agrometeorological variables on soybean productivity: mean air temperature [TMean] (ºC), accumulated rainfall value [Rain] (mm), global solar radiation [Sr] (MJ m-2 day-1), and potential evapotranspiration [ETp] (mm), in ten-day variations of the the maximum vegetative development date (MVDD), in the 2011/2012 and 2013/2014 harvest years in the state of Paraná. The study was based on spatial distribution of variables, using univariate and bivariate Global Moran’s Indexes, and multivariate clustering analysis. To verify seasonality in the time distribution of the agrometeorological variables in the ten-day variations close to soybean MVDD, we used the circular statistics, through the mean vector length (R). Result it was identified regions of the state that have higher and lower rainfall and seasonality, also have higher and lowest productivity, respectively. That the variation in soybean productivity between harvest years was correlated with the agrometeorological variables, and rainfall volume is an important factor in productivity. The other agrometeorological variables occurred uniformly, especially in 2011/2012 harvest year, in the Northwest, Central-northern and West mesoregions. Furthermore, there was clustering of regions with similar spatial distribution of the evapotranspiration and rainfall variables in 2aDMDV2d in the 2011/2012 and 2013/2014 harvest year, showed the same spatial distribution of the agrometeorological variables and the productivity variable.

Evaluating the Pollution Risk of Soil Due to Natural Drainage of Orange Peel: First Results

Orange peel (OP), the main residue of the citrus industry, is usually used for animal feeding and soil fertilisation if more advanced options are lacking. In areas with warm and dry climatic conditions, OP is land-spread for solar-drying on the fields, the leachate produced is a potential pollution factor for soil especially due to the release of organic matter; heavy rainfalls could even aggravate the hazard. Since literature does not report any quantitative evaluation of this risk, this study presents three OP drainage tests in lysimeters, where OP was left releasing leachate on a soil layer. A first test was carried out on raw OP naturally draining, while, in a second and a third test, a rainfall of 100 mm was applied on already drained and solar-dried OP, respectively. After drainage, raw OP reduced its initial volume by about 90% and the leachate production accounted only for about 20% of the initial volume. The simulated rainfall produced even lower volumes of leachate (2–3% of the initial biomass volume), in spite of the high rainfall volume and long drainage time after its application. The COD concentration in the leachate from the raw OP was significantly higher than those produced after simulated rainfall. However, the COD amount released to the soil was negligible. The lysimetric tests showed that the release of leachate occurs mainly during the first phase of drainage and that rainfall is absorbed and does not produce significant leaching. Overall, the risk of soil pollution due to the natural drainage of OP is negligible, due to both limited amounts of leachate and organic loading.

How Characteristics of a Rainfall Event and the Meteorological Conditions Determine the Development of Stemflow: A Case Study of a Birch Tree

The process of rainfall partitioning is usually addressed by three components: rainfall interception, throughfall and stemflow. The occurrence and proportion of stemflow depends on many complexly interconnected factors. To contribute to the interpretation of these interdependencies, the influence of rainfall event characteristics and phenoseasons on stemflow development was analyzed with a new approach. In this study we have focused on the development of stemflow during 156 rainfall events with complete time series records for a single birch tree (Betula pendula Roth.) at a study plot in the city of Ljubljana, Slovenia. For each one of the selected events, diagrams of rainfall and stemflow development during the event were prepared and grouped according to their visual similarities using hierarchical clustering. Additionally, significant meteorological characteristics were determined for each group of events. Four characteristic types of stemflow response were identified and connected to the corresponding event characteristics. Events showing negligible stemflow response to rainfall increase were characterized with rainfall amounts lower than 5 mm, high rainfall intensities, and occurrence in the leafed phenophase. A slow stemflow increase, independent of the increase of the rainfall volume in the open, was recognized for rainfall events delivering less than 20 mm of rainfall during a 5-h duration on average. The majority of these events were observed in the leafed phenophase, corresponding to higher air temperature and vapor pressure deficit. The occurrence of stemflow events, whose development followed the increase of the rainfall amount, was not dependent on the phenophase. However, during these events the average air temperature and vapor pressure deficit were lower, the rainfall amount was larger and the rainfall duration longer in comparison to the events showing independent increase with rainfall. The fourth type of response of stemflow was defined by a strong stemflow response in connection to large rainfall amounts and the longest rainfall duration, as observed for events in the leafless period. The four characteristic types of stemflow response provide additional information on the possible proportion of the rainfall reaching the ground as stemflow.

A Coupled Numerical Investigation of the Cape Fear River Basin during Hurricane Florence (2018)

In this study we adapted WRF-Hydro to the Cape Fear River basin (CFRB) to assess its performance during Hurricane Florence (2018). The model was first calibrated with a strategy of mixture of automatic and manual calibration during Florence and then evaluated with an independent hurricane event. With satisfactory NSE values (>0.4) achieved at all gages for hourly simulation, the model demonstrates its potential in simulating the flood response at both basin and sub-basin scale during hurricane events. The model’s capability in reproducing rainfall and properly translating it to hydrological response was further evaluated. The analysis suggests that the calibrated WRF-Hydro in combination with a series of WRF simulation using different microphysics schemes can provide reasonable flood simulations. The model reproduced peak streamflow observed at gage stations with acceptable errors in timing and amplitude. Meanwhile, positive(negative) bias in rainfall input is likely to be amplified (reduced) in streamflow forecast when simulated rainfall volume is larger than the “model true”. And the timing bias mostly inherited from rainfall simulation and calibration process.

RESERVAÇÃO DE ÁGUA PLUVIAL PARA USO NÃO POTÁVEL NO COLÉGIO CECAFE NO MUNICÍPIO DE SANTA FÉ DO SUL – SP

Essencial para a manutenção da vida, a água está se tornando cada vez mais escassa devido à poluição e ao uso irracional. A busca por soluções ao uso indevido dos recursos hídricos requer atitudes que visem diminuir o desperdício e o consumo irracional da água. Esse trabalho foi realizado com o objetivo de propiciar o aproveitamento das águas pluviais através do escoamento e captação superficial dos telhados, para o reuso dessa água em descargas sanitárias, lavagens de pátios e irrigação da área de vegetação no colégio Centro de Ensino Caminho Feliz, situado no município de Santa Fé do Sul/SP. A metodologia aplicada foi revisão bibliográfica e, partindo dela, a pesquisa de campo de caráter exploratório e quantitativo, baseada na rotina e na parte estrutural do colégio. Os dados estudados para a realização dessa pesquisa foram o volume de precipitação mensal e a variação da temperatura média na cidade, fornecidos pelo Serviço Autônomo de Água e Esgoto e o reservatório determinado através do método de Rippl. O volume definido para a cisterna foi de 20.000 litros, levando em consideração o número de frequentadores da instituição. Diante do exposto, entende-se que a implantação do sistema de captação e armazenamento da água da chuva é viável e eficiente, considerando o investimento, o colégio terá uma economia de 25% na fatura e o retorno financeiro em um prazo de 7 anos, além disso, a redução do consumo de água de abastecimento público pela instituição será em torno de 720.000 litros ao ano. RAINWATER STORAGE FOR NON-POTABLE USE AT CECAFE SCHOOL IN THE MUNICIPALITY OF SANTA FÉ DO SUL - SP ABSTRACT Water is essential for the maintenance of life; it is becoming increasingly scarce due to pollution and unreasonable use. The search for solutions due to the misuse of water resources urges the attitudes aiming at reducing the waste and irrational water consumption. This paper was carried out with the purpose of promoting the use of rainwater runoff and surface collection from roofs, reusing this water for flushing, washing the courts, and watering the garden area at Centro de Ensino Caminho Feliz school, located in the municipality of Santa fé do Sul-SP. Bibliographic review was the method used, through this one, the field research was exploratory and quantitative, based on the routine and the facilities of the school. The data that was analyzed to accomplish this research were the monthly rainfall volume, and average temperature variations in the city, which were provided by Serviço Autônomo de Água e Esgoto, as well as the reservoir specified by the Rippl method. The volume given to the cistern was 20.000 liters, considering the number of attendees in that Institution. In view of that, we understand that the rainwater storage system is feasible and efficient, considering the investment, that school will save around 25% in the bill and the financial return will occur in 7 years, besides, a decrease in public water supply in that institution will be around 720.000 liters per year. Keywords: Rainwater; Cisterns; Collection; Rainwater Storage.

Desiccation of Wetlands and Their Influence on the Regional Climate. Case Study: Ciénaga de Aguablanca, Cali, Colombia

The desiccation of wetlands is a process associated with the dynamics of urban growth and expansion of the agricultural frontier. This article aims to evaluate the influence of the desiccation of the Ciénaga de Aguablanca on regional climate. The periodization of the desiccation and urban growth of Cali was reconstructed under the theoretical contributions of environmental history. As complementary sources, maps, aerial photographs, and diagrams of the city were obtained from 1944 to 2020, with which the hydromorphological changes in the Ciénaga de Aguablanca were represented. Data from six hydroclimatological stations were statistically analyzed with Pettitt’s test, trend analysis, and Rclimdex. The results indicate a reduction of 99% in the area of the wetlands, from 19.2 km2 in 1944 to 0.2 km2 by 2020. Additionally, a break point was observed in 1970, preceded by the process of wetland desiccation and waterproofing of the eastern part of Cali, along with significant differences between temperature series inside and outside the urban perimeter. Another break point was detected in 1985 in the flow series, associated with the construction of the La Salvajina dam. Monthly rainfall showed a tendency to increase, but its temporal distribution was uneven, given that rainfall volume showed a tendency to increase over short times. Regional climate changes can occur at a much faster rate than global variations due to the anthropogenic actions of wetland intervention.

Efeitos da dinâmica pluviométrica na interceptação e precipitação interna em uma encosta com Floresta Atlântica no Parque Nacional da Tijuca, RJ, Brasil

Given the importance of vegetation cover for the hydric balance, the present paper aimed to analyze the pluviometric dynamics for the net precipitation and interception process, in the forested hillslope in the Tijuca National Park. The influence by a set of independents variables given by hydrometeorological dynamics (rainfall volume and intensity and drought context) was discussed face the temporal modulation for interception and net precipitation, coupled a spatial analyze given by comparisons between hillslope positions (summit; upper hillslope; lower hillslope; valley bottom), where there is a vegetation structure heterogeneity originated by geomorphological context. The volume intercepted at each event varies directly proportional to the antecedent drought time, with the complementary effect of the rainfall volume in the previous 15-days. The percentual interception varies inversely proportional to the gross precipitation and its intensity. It is about the interception wich best manifests the significance of the spatial variations, with highlights for the summit área, where the canopy openness is bigger. The net precipitation varies under the strong influence – directly proportional – by gross precipitation volumes, being better explained with the complementary effect by the previous drought. The spatial variations on the net precipitation are less significant in comparison to the interception, decreasing the significance in the time of increase of the gross precipitation volumes.

Pluviometric patterns in the São Francisco River basin in Minas Gerais, Brazil

ABSTRACT This work aimed to evaluate the spatial-temporal variability of precipitation in the Minas Gerais section of the São Francisco River basin, an area of substantial socio-environmental relevance for the country and which has presented recent events of water scarcity. Multivariate and non-parametric statistical analyses were applied to the monthly precipitation data from 131 pluviometric stations, covering a period from 1989 to 2018. The results indicated distinct homogeneous pluviometric regions with greater spatial variability in rainfall patterns in the southern regions of the basin. Results from the temporal analysis indicated seasonality in the rainfall patterns for all seasons, with the rainy period predominantly occurring between October and March for the entire Minas Gerais section of the São Francisco River basin. No rainfall trend was identified in 78% of the stations, with the other stations (22%) showing a trend toward a reduction in rainfall volume.

Temporal Variations in Rainfall Volume in the Southwest of Western Australia

Rainfall in the southwest of Western Australia (SWWA) has decreased significantly over recent decades. Previous studies documented this decrease in terms of the change in rainfall depth or decrease in the frequency of rainfall events for selected sites. Although rainfall volume is of vital importance to determine water resources availability for a given region, no study has yet been undertaken to examine the change in rainfall volume in SWWA. The aim of this study is to examine the spatiotemporal changes in rainfall volume and to attribute this change to the changes in wet area and rainfall depth. Gridded daily rainfall data at 0.05° resolution for the period from 1911 to 2018 were used for an area of 265 952 km2 in SWWA. For the whole region and most zones, rainfall volume decreased, which was mostly due to a decrease in the wet area, despite an increase in the mean rain depth. In the regions near the coast with mean annual rainfall ≥ 600 mm, 84% of the decrease in rainfall volume could be attributed to a decrease in the wet area, whereas the decrease in rainfall depth only played a minor role. The regions near the coast with a higher number of rain days showed a decreasing trend in wet area, and the regions farther inland with a lower number of rain days showed an increasing trend in wet area. On the coast, the rate of decrease in rainfall has been reduced, and heavy rainfall, in fact, has increased over the past 30 years, although there was no concurrent change in the southern annular mode (SAM). This suggests that the relationship between SAM and rainfall could have changed and that other climate drivers could also be responsible for the recent rainfall trend and variations in the coastal regions of SWWA.