Study of morphometry and land coverage to help urban planning in Barbosa and Barbosinha Brooks watershed, Lins - SP

Urbanization in hydrographic basins promotes changes in the hydrological cycle through the impermealized areas. Not only surface runoff is increased, reducing infiltration, but also the susceptibility to extreme hydrological events. The objective of this study is to analyze the natural susceptibility of Córregos Barbosa e Barbosinha (Barbosa and Barbosinha Brooks) watershed to flooding. Morphometric parameters of land use and occupation were analyzed, in order to subsidize management and planning in an area of urban expansion. The analysis of land use and occupation was based on the supervised classification method of Landsat-5 Thematic Mapper (TM) sensor and Landsat-8 Operational Land Imager sensor (OLI) satellite images dated 1990, 2006 and 2020. Morphometric indices were calculated using the SPRING 5.4.3 software and a SRTM image with a spatial resolution of 30 meters. The results indicate that the natural susceptibility to flooding of the study area is medium to high, and can be intensified by the dynamics of land use and occupation and increasing impervious areas in the basin. Over the period of study, the growth of impervious areas was 133% relative to 1990.

Storm Water Management

Over the past years, rapid growth due to urbanization and industrialization, the changes in Land over and land use patterns have resulted in permanent environmental pollution to the hydrological processes. The hydrological cycle in cities is seriously affected due to increasing impervious areas as a result of urban development which has enhanced the risk of urban flooding. The increase in the impermeable area decreases infiltration, increases the runoff and reduces the time of concentration. Hence, for a given amount of rainfall, greater flooding is generated. Understanding the scope and limitation of sustainable stormwater management techniques detailed literature review is carried out. Site suitability is based on spatial analysis of data like geomorphology, slope, recharge condition, landuse and Landover map. Then analyzing local site conditions possible techniques that could be used to manage stormwater runoff are recommended and conclusions are drawn on the same.

Design guidelines for on-site stormwater detention

The city of Curitiba-PR has a municipal decree that establishes the criteria for the design of flood detention tanks. However, these guidelines do not guarantee minimum efficiency during operation, as it may vary depending on their base area, water depth and flow regulating orifice diameter. In this research, a design method was proposed, establishing some new criteria that relate impervious areas of the lots to the tank design parameters. The efficiency definition was established with the premise that the tanks should provide the return of flows from an impervious area to its pre-urbanization scenario. This reduction was established as 70% of the peak flow in the city of Curitiba-PR. Based on simulations of flow routing with the Puls Method, the optimum geometric characteristics (volume, area, water depth and orifice diameter) of the tanks were obtained to guarantee the decrease in the peak. Comparing the results obtained from the municipal legislation design, the new method provided n minimal efficiency and a decrease of 24% of the tank volume.

SENTINEL-2A BASED IMPERVIOUSNESS MONITORING OF URBAN BUILT ENVIRONMENT

The cities where the future happens first, they are open, creative, cosmopolitan and sexy and the perfect antidote to reactionary nationalism but the urbanization in unplanned manner is becoming an environmental-social-economical threat to accommodate the huge number of population which is literally boosting the present situation of climate change due to global warming. Extracting, measuring and treating the urban area which compiles of dense built-up and complex road network, is very essential to decrease the negative impact on environment. If most of the impervious surfaces can be replaced with permeable or semi-permeable materials or solar panel then the habitation will be saved from natural disastrous events like heat wave and flash flood. Urbanization can be categorized mainly into two: a) Static (urban open space + built space) and b) Dynamic (transportation). The static and dynamic urbanizations largely consist of impermeable or impervious materials. Impervious surfaces are alluded as the anthropogenic elements through that water can't infiltrate into the soil, such as streets, driveways, parking areas, houses, structures etc. An urban area is a densely populated human settlement, facilitated with multiple infrastructures including built and un-built. These areas or settlements are categorized as towns, suburbs, cities by urban morphology. Through balancing the ratio between the un-built (urban space) and built (building & roads), urban disastrous events can be minimized. This research mainly focused on the extraction of impervious areas using regression modelling approach which is used to generate an impervious surface map from Sentinel-2A dataset of Delhi. Utilising multiple normalised indices can provide better classification results. This study shows that in urban areas imperviousness is becoming one of the prominent computational parameter and monitoring impervious areas could help us understand a lot of urban phenomena which are built-up induced and its rapid change in urban environment is giving rise to unhealthy living conditions.

Hydrological response in a highly urbanized watershed in China

Urbanization has a strong signal on the hydrologic cycle, leading to reduced infiltration, and faster and larger runoff. However, less is known in watersheds that have been experiencing such a large and rapid urbanization as those in China. Here we focus on the Wenyu watershed, a fast urbanizing basin located in the Beijing metropolitan area. Using a statistical attribution framework, we examine the hydrological response to the increasing urbanization across a wide range of discharge quantiles, from low to high flows; moreover, we perform analyses at the seasonal scale to capture differences in the physical processes at play during the year. In addition to impervious areas, we also consider precipitation, temperature, antecedent wetness, recycled water amount, and groundwater level as potential predictors. Results indicate that our models can capture well the variability in streamflow in this highly urbanized basin. Overall, urbanization played a different role for the different seasons and discharge quantiles. More specifically, we find its strongest impact to be in winter and spring, and for low and median quantiles. The role of precipitation is the strongest in summer, and it increases as we move towards the upper tail of the discharge distribution. Recycled water, on the other hand, tends to play a more dominant role in winter and spring.

Development of a Three-Source Remote Sensing Model for Estimation of Urban Evapotranspiration (TRU)

<p>Evapotranspiration (ET) from an urban area and its components are important  when estimating the urban ‘heat island’ effect and the urban hydrological cycle. Multi-source satellite-based ET models for ecosystems (e.g. farmland, forest, and wetland) have been developed and applied, but satellite-based ET model dimensions for urban areas are lacking, especially since all currently available models are designed for single-source schemes. This paper proposes the first Three-source Remote sensing model for Urban areas (TRU) to discriminate between soil evaporation, vegetation transpiration, and impervious surface evaporation. TRU uses a new parameterization scheme, based on the use of a complementary relationship integrating soil surface temperature to estimate soil evaporation. An iterative procedure was developed for decomposing land surface temperature (LST) into component temperatures. Also, the ET for impervious areas was independently delineated using the “patch” approach. The model was tested for 45 cloudless days in Tianjin for 2017-2020 based on 30 m Operational Land Imager (OLI)/Enhanced Thematic Mapper Plus (ETM<sup>+</sup>) images. Results indicated the root mean square error (RMSE) of 38.8 W/m<sup>2</sup> and Bias of 9.9 W/m<sup>2</sup> compared with two Eddy Correlation (EC) observations for instantaneous latent heat (LE) simulation and RMSE was 0.087 and Bias was -0.012, compared with stable water isotope measurements for the estimation of the ratio of vegetation latent heat flux to latent heat flux (LE<sub>v</sub>/LE).Comparison with urban single-source models and two-source models for ecosystem suggest TRU provide best accuracy for ET and its components simulation. The spatial pattern suggested impervious surface evaporation exhibited minimal seasonal variation and maintained a very lower level due to limited availability of water. The results emphasized the importance of using land use and land cover (LULC) in urban ET modeling and the necessity to calculate ET as independent of impervious areas. TRU represents a groundbreaking development of multi-source urban satellite-based ET models and facilitates the mapping of urban ET components.</p>

Determination of field capacity in the Chibunga and Guano rivers micro-basins

Background: The micro-basins of the Chibunga and Guano rivers are located within the sub-basin of the Chambo River, which starts at the thaw of the Chimborazo, crosses the cities of Guano and Riobamba, and ends in the Chambo River. These rivers are considered fluvial hydrological forces and geological limits of the aquifer, located in this sub-basin. For this reason, our investigation addressed the field capacity in the micro-basins of Chibunga and Guano rivers, to determine the maximum retention potential, i.e., the saturation of water in the soil. Methods: We investigated the change of precipitation to runoff through the correlations between the characteristics of the soil and its vegetation. We applied the Curve Number (CN) method introduced by the United States Soil Conservation Service (USSCS); this represents an empirical model, which relates the vegetation cover to the geological and topographic conditions of the soil. Along with the geographic information system, the model allows to represent the variation of runoffs for each micro-basin, according to the different land use categories, over the time frame from 2010 to 2014. Results: We found that the maximum retention potential is directly affected by CN values, representing the runoff potential. Highest values of 100 belong to the wetlands, urban area, snow, and water, as rain is converted directly into runoff, being impervious areas. The Guano river micro-basin possesses clay soil with CN of 78, the soil texture for eucalyptus forest is clay loam, and its CN value, 46, is the lowest of the data set. Knowledge of field capacity allows to properly evaluate the storage capacity of soil and water conservation. Conclusions: Results of this work will be useful in the quantification of the water balance, to determine the water supply and demand.

Modeling the Effectiveness of Cooling Trenches for Stormwater Temperature Mitigation

Due to elevated runoff stormwater temperatures from impervious areas, one management strategy to reduce stormwater temperature is the use of underground flow through rock media termed a cooling trench. This paper examines the governing equations for the liquid phase and media phases for modeling the temperature leaving a cooling trench assuming that changes in temperature occurred longitudinally through the cooling trench. This model is dependent on parameters such as the media type, porosity, media initial temperature, inflow rate, and inflow temperature. Several approaches were explored mathematically for evaluating the change in temperature of the water and the cooling trench media. Typical soil–water heat transfer coefficients were summarized. Examples of predictions of outflow temperatures were shown for different modeling assumptions, such as well-mixed conditions, batch mixing and subsequent release, and steady-state and dynamic conditions. Several of these examples evaluated how long rock media would cool following a stormwater event and how the cooling trench would respond to multiple stormwater events.

Evolução Espaço-Temporal da Ocupação Urbana Sobre Áreas Naturais em Ambientes Costeiros

This work aimed to perform a multidecadal analysis of the spatio-temporal evolution of urban occupation over natural areas in the South and West Zones of the Natal-RN city, through geotechnologies and field study. Between 1969 and 2013, the impacts of urban expansion on tthe main Permanent Preservation Areas - PPA (banks of rivers and lagoons, and dunes remaining) and their temporal changes were identified and characterized. For this, aerial photographs, satellite images and contour lines were used, in addition to pre-existing information, which allowed the creation of a robust spatial database, which resulted in the construction of evolution maps of impervious areas and the use of and land occupation. In general, it was found that urban occupation advanced about 60% over the studied natural areas. This advance was increasing until 2006, when there was a slowdown in this process, except for the Environmental Protection Zone (EPZ) 03, where the Pitimbu River and its PPA are located, which experienced a more significant loss of area. The urban occupation affected the natural drainage and contributed to the contamination of the groundwater of Natal, due to the increase of the waterproofed area, the release of solid and liquid residues, as well as the removal of the riparian forest, which irreversibly altered the natural landscape. And reduced the quality and quantity of local water resources needed by the population.

Improvement of comprehensive performance of compound green soil in sponge city

Large-scale constructions of urbanization increase the impervious areas of city, leading to the urban hydrological effects such as urban waterlogging and rainwater runoff pollution. To this end, China proposed to adopt the measure to build sponge cities. However, the existing green soil cannot meet the comprehensive needs of sponge city. In order to quickly evaluate the comprehensive performance of the soil in sponge city, a comprehensive evaluation criterion was designed, which is related to the characteristics of greening soil permeability, porosity, pH, salinity and fertility. Based on the criterion, a new type of composite green soil was obtained with the silt soil: medium sand: sawdust ratio of 72.5%: 20%: 7.5%. Finally, compared with the existing soil, the new green soil not only meets the comprehensive performance requirements of the green soil's fertility, pH, permeability and other factors, but also has higher permeability and water retention. It was proved that the new green soil has apparent advantages in the control of rainwater.