Urban and Peri-urban Soils for sustainable development: properties, degradation status and management challenges
Urban and peri-urban areas comprise a wide variety of soils, ranging from semi natural (e.g., urban forest) to highly disturbed soils (e.g., constructed areas), with great variability in short distances. This spatial variation represents a major challenge to investigate, classify and characterize the physical, chemical and biological properties of the soil. Soil properties determine their ability to provide ecosystem services, such as food production, water regulation, carbon sequestration and recreation. Increasing human pressure in urban and peri-urban environments is a cause of soil degradation and compromise their ability to provide ecosystem services in quality and quantity, and build resilience to global changes. This session aims to discuss (i) methodologies to assess the spatiotemporal variability of urban and peri-urban soils, including the use of soil quality indices, (ii) soil ecosystem services; (iii) main soil threats leading to soil degradation, such as sealing, compaction, erosion, contamination/pollution and biological decline in soil quality; and (iv) strategies to enhance ecosystem functions and services of urban and peri-urban soils, particularly focused on nature-based solutions. Studies emphasising the role of soil to improve urban sustainable development, namely through the use of information about soil quality to support urban planning strategies and optimizing ecosystem services are very welcome. Discussion to promote a more efficient and sustainable use of soil and improving soil-related decision-making processes at international, national, regional and local levels are encouraged in this session.
Laurent Lassabatere, Anne-Cécile De Giacomoni, Rafael Angulo-Jaramillo, Gislain Lipeme Kouyi, Matteo Martini, Cédric Louis, Pierre-Emmanuel Peyneau, Veronica Rodriguez-Nava, Benoit Cournoyer, Axel Aigle, Emmanuelle Bergeron, Jérémie Bonneau, Sofia Bouarafa, Yannick Colin, Paola Concialdi, Simone Di Prima, Wessam Galia, Thanh Huong Lai, Arthur Marais, and Marjolet Laurence and the following co-authors
The extension of urban and peri-urban areas and the related artificialization of soils drastically impacts the water cycle as well as biogeochemical cycles. In particular, the sealing of soils with impervious surfaces such as roads increases runoff and decreases concomitant infiltration. At the catchment scale, more significant amounts of stormwater must be collected and managed to prevent from flooding urban areas and mitigate discharge to the environment. Sustainable Urban Drainage Systems (SUDS) were developed to alleviate these problems. These systems allow the restoration of one of the main functions of urban and peri-urban soils, i.e., infiltrating stormwater. They simultaneously reduce the risk of flooding and increase groundwater recharge. Another essential service must be ensured and optimized: the removal of pollutants from infiltrating water by the soil, to avoid the degradation of the quality of the groundwater.
The INFILTRON project aims to design a methodology for the assessment of infiltration and filtration of pollutants by SUDS. The project is a collaboration of many partners, with expertise in soil physics, urban hydrology, nanoparticle engineering, and modeling, to engineer a specific device for the simultaneous monitoring of water infiltration and pollutant filtration. This infiltration device both infiltrates water and injects nanoparticles (NPs) into the soil. It was sized to account for preferential flow, which is known to have a significant impact on infiltration and pollutant transfer. The engineered NPs were designed to be detectable in the ground using ground-penetrating radar (GPR) and to mimic the transfer of nano-pollutants (emerging pollutants, bacteria, etc.) commonly found in real stormwater. An infiltration-filtration model was developed to interpret the experimental data and to quantify two indicators for the assessment of water infiltration and pollutant filtration. INFILTRON will provide a very interesting toolbox for practitioners and stakeholders for the evaluation of the infiltration and filtration functions of not only SUDS within the framework of stormwater management, but also anthropized soils within the management of urban and peri-urban areas.
How to cite:
Lassabatere, L., De Giacomoni, A.-C., Angulo-Jaramillo, R., Lipeme Kouyi, G., Martini, M., Louis, C., Peyneau, P.-E., Rodriguez-Nava, V., Cournoyer, B., Aigle, A., Bergeron, E., Bonneau, J., Bouarafa, S., Colin, Y., Concialdi, P., Di Prima, S., Galia, W., Lai, T. H., Marais, A., and Laurence, M. and the following co-authors: INFILTRON package for assessing infiltration & filtration functions of urban soils, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11269, https://doi.org/10.5194/egusphere-egu2020-11269, 2020.
Carla Ferreira, Barbara Frigione, Milan Gazdic, Michelle Pezzagno, and António Ferreira
Soil is a non-renewable resource subject to increasing degradation favoured by human activities, such as the creation of impervious surfaces. Driven by increasing global population, soil sealing became a major challenge due to growing expansion and its impact on decreasing ability of soil to provide ecosystem services. In order to mitigate the environmental and social impacts of sealing, a worldwide interest in greening the cities have been noticed among politicians and stakeholders. Urban green areas provide benefits for the urban water cycle, namely through reducing stormwater runoff and flood hazard. The effectiveness of green areas inside the cities on runoff reduction, is still not well understood. This is partially due to the role of complex landscapes, including distinct urban types (e.g. residential vs commercial) and spatial patterns, on rainfall-runoff processes. This study aims to investigate the impact of different spatial patterns of sealing and green areas on surface runoff. Inspired on the spatial patterns of green areas observed in several Portuguese city centres crossed by rivers, three spatial patterns were investigated: dispersed gardens with a narrow green strip along the stream (SS); small gardens along contours, with a large green strip downslope (HD); linear gardens along the slope, with a large green strip downslope (VD). The impact of these three patterns was assessed through lysimeter experiments, using concrete blocks to simulate sealed surfaces and turfgrass to mimic gardens. All the configurations included 60% sealing and 40% greening, which is the maximum allowed in several Portuguese municipalities for urban areas. The lysimeters have an area of 1.24 m2 and a depth of 0.15 m, filled with sandy loam soil (1.4 kg/m3) bellow the pavement and the turfgrass, and are placed with a 13º-16º slope. The lysimeters were installed in October 2019 and are subject to natural rainfall. After each storm, runoff and leachate measurements have been performed. Three soil moisture sensors were installed per lysimeter, at 10 cm depth, and provide continuous records with 5 min intervals. Rainfall data is collected with a rain gauge installed nearby, with a 5 min resolution. Results show that 40% turfgrass is able to cope with the majority of rainfall and runoff from upslope paved surfaces. Runoff coefficient is typically less than 2% and attained a maximum of 4% during the largest (40 mm) and more intensive storm (9.4 mm/h). Although increasing soil moisture slightly enhances runoff generation, the spatial patterns investigated at small scale did not show significant impacts on rainfall-runoff processes. Turfgrass revealed effective to retain and infiltrate rainfall and runoff from paved surfaces. It may provide an adequate solution to mitigate the impact of urbanization on the water cycle and flood hazard within cities.
How to cite:
Ferreira, C., Frigione, B., Gazdic, M., Pezzagno, M., and Ferreira, A.: Effectiveness of green areas and impact of the spatial pattern on water infiltration within cities, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-441, https://doi.org/10.5194/egusphere-egu2020-441, 2019.
Hanmin Choi, Youjin Kim, Inhye Seo, and Gayoung Yoo
Urban soil is the foundation of ecosystem functioning in urban green spaces, which plays an important role in sustainable urbanization. To maintain the ecosystem services provided by urban green space, it is important to manage and monitor the urban soil using appropriate evaluation parameters. Given that the urban soil is under direct and indirect influence of anthropogenic factors, the characteristics of urban ecosystem should be considered when assessing the soil quality. My research group already suggested a new soil quality parameter set for urban roadside soils, which is composed of soil penetration resistance (PR), pH, the C/H ratio of particulate organic matter (POM-C/H), POM-N, and soil microbial respiration (RES). This parameter set indicated that the urban soil has very unique quality of soil organic matter (SOM) and it should be considered as well as SOM quantity when assessing the urban soil status. In this study, we aimed at assessing the SOM quality in various types of urban green space using the C/H ratio and N of POM and analyzing the relationship between SOM quality and soil RES. Soil RES was regarded as a representative parameter for overall soil health and used as a dependent variable. The study was conducted in three different types of urban green spaces, which are roadside, urban park, and riverside green in Seoul, Korea. In each type of green space, three sites were selected varing in the degree of human disturbance. Soil samples were collected from the 0-15 cm depth, passed through 2mm sieve and dried before analysis. The POM was separated after wet sieving using 53 um screen and the C, N, and H contents of POM were measured using combustion analysis using the Carlo Erba NS Analyzer Carlo Erba, Milan, Italy). We calculated the POM-C/H as a proxy for aromaticity, which increases with high non-degradable OM. To trace the source of SOM, we measured the N stable isotope ratio of POM (POM-δ15N). On the same day of soil sampling, soil RES was measured on-site using the EGM CO2 Gas Analyzer PP Systems, MA, USA). We performed multiple regression to analyze the relationship between SOM quality and soil RES. The POM C/H was higher in roadside soil than urban park, which means the urban roadside soil has a significantly higher amount of non-biodegradable compounds such as PAH. This further implies that OM quality is significantly different among types of urban green spaces. Using the POM delta N value, we found that OM in the roadside soils was originated from sewage sludge, animal urine/feces as well as atmospheric deposition. Analysis of OM source tracing in the urban park and riverside soil will be conducted. There was a negative correlation between POM C/H ratio and soil RES, which indicates the poor soil health condition partly due to low OM quality. In conclusion, this study clarifies the importance of OM quality for assessing the soil in urban green spaces affected by anthropogenic factors and indicates that the SOM quality management needs to be established.
How to cite:
Choi, H., Kim, Y., Seo, I., and Yoo, G.: An Analysis of Soils in Various Type of Urban Green Spaces Based on the Soil Organic Matter Quality, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21200, https://doi.org/10.5194/egusphere-egu2020-21200, 2020.
Urban green spaces regulate city air temperatures, particularly mediating the urban heat island effect. Urban below ground temperature regulation is less studied, but known to have a significant effect on urban heating by regulating temperature through heat transfer and thermal conductivity. The impacts of climate change, such as the increased frequency and intensity of heatwaves, will exacerbate urban heating effects, having significant impact on urban citizens. We installed low cost temperature sensors in topsoils across a gradient of urban green spaces (parking lots, rewilded areas, managed grassland, biodiversity plots, woodland) in the Cranfield Urban Observatory (UK). The soil temperture sensors measured continously during June and July 2019 and included two periods of record breaking heatwaves in Europe in late June and July. As expected, the results showed significant variations in soil temperature between the urban green space types, where parking lot soils showed higher and flasher temperature regimes compared with all other green spaces. Urban woodland had significant dampening effects on soil temperatures. The managed green spaces responsed differently to the heatwave events and grassland soils retained heat for longer compared with areas planted with wildflower mixes (biodiversity plots). Therefore, urban planning should prioritise the type of green spaces within urban developments to take into account the different regulatory effects of heat, particulaly under the projected effects of a changing climate.
How to cite:
Hannam, J. and Nandozi, C.: Using low cost sensors to assess soil temperature response to summer heatwaves in urban greenspaces. , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18007, https://doi.org/10.5194/egusphere-egu2020-18007, 2020.
Jessica Davies, Roisin O'Riordan, Carly Stevens, John Quinton, and Chris Boyko
Soil in urban areas has largely been left out of traditional soil research, however, there is now a growing interest in its importance due to the key role that cities will play in a more sustainable future. Soil provides vital ecosystem services, and these are becoming more pertinent for cities as the population of urban areas continues to grow. Services such as flood regulation, urban food growing, urban heat island mitigation and carbon storage, as well as cultural and recreational services, are unpinned by the healthy functioning of soils.
The role of urban soil in providing ecosystem services in urban areas is understudied, and the complexities of understanding and quantifying soil ecosystem services has yet to be translated to the varied and highly heterogeneous context of cities. In this work, we will review the literature on soil ecosystem services in cities and present a state-of-the-art picture of current knowledge.
We will discuss the variation of urban soils, their treatment and management in urban areas, and the associated difficulty in investigating and classifying them. The trends of urban soil ecosystem services research will be presented, considering which services have been most commonly studied across supporting, provisioning, regulating and cultural categories; and in which countries. A co-occurrence analysis of key terms in the literature will also be presented, highlighting further patterns and gaps in knowledge. This will also lead to a discussion on the key drivers behind the soil threats in urban areas, such as soil compaction, sealing with impervious surfaces and contamination.
The most studied services will be investigated further to allow a more detailed discussion into what we know about these services, and the impacts of urbanisation on their provision. This presentation will bring together the growing body of work on this relatively new research area, will identify gaps in our knowledge, and will highlight the impacts of urbanisation for urban soils. This will inform the way we treat and manage soil in urban areas, helping to optimise the provision of urban soil ecosystem services and contributing to more sustainable urban development for the future.
How to cite:
Davies, J., O'Riordan, R., Stevens, C., Quinton, J., and Boyko, C.: Urban soil ecosystem services: contributing to sustainable urban development , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20260, https://doi.org/10.5194/egusphere-egu2020-20260, 2020.
Zahra Kalantari, Andrea Gadnert, and Carla Sofia Santos Ferreira
Nature-based solutions have the potential to provide a wide range of essential ecosystem services as well as water management goals. As the majority of the global population lives in cities, NBS for addressing water management in urban areas is of great importance. Despite the recent advances and growing experiences with the implementation of NBS, there is still below 1% of the total investment in water resource management infrastructure that is dedicated to NBS in urban areas? One of the current obstacles for implementation is the lack of knowledge, data and information about the design and implementation of NBS for water management. Although there has been a growing interest in NBS in recent years, there are still a large need for a comprehensive evidence based on the effectiveness of NBS. Therefore, there is also a need for monitoring both the process of implementing NBS as well as the outcomes, including the final benefits of the NBS, how the NBS is perceived and how it responds to the challenge for which it was implemented. The aim of this study is to assess the effectiveness of nature-based solutions (NBS) for urban resilience in particular for water management in different climate zones, focusing on cities that have worked or are planning to work extensively with NBS. This study explores which opportunities and barriers current regulatory frameworks and management practices imply and how the former can be reaped and the latter overcome, for implementation of effective NBS. The study focuses on the analysis of available data bases of NBS in different cities This study also creates an inventory of indicators used to assess the NBS effectiveness, covering a range of social, economic and technical aspects.
How to cite:
Kalantari, Z., Gadnert, A., and Ferreira, C. S. S.: Nature-based solutions for urban resilience, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5963, https://doi.org/10.5194/egusphere-egu2020-5963, 2020.
Tom Leroi, Cécile Le Guern, Béatrice Béchet, Christophe Ducommun, Joël Moulin, Bertrand Laroche, Clémentine Duvigneau, Catherine Keller, Catherine Néel, Fabienne Marseille, and Philippe Branchu
Urban planning historically considers soils as a support for infrastructures. Hopefully, awareness is increasing on the fact that soils offer many more services than just this one, thanks to their various functions. It is therefore necessary to develop methodologies and tools that allow the urban planners to take into account the opportunities and constraints associated to soils. Considering the existing quality indexes already developed by the researchers, we faced within the MUSE project various difficulties and in particular the lack of knowledge on urban soils in France. We therefore developed a methodology to deal with limited knowledge on urban soils and tested it first on the Nantes metropolis territory (France). Our aim was to map each soil function as well as a soil multifunctionality in such a way that urban planning documents may refer to them.
The aim of the multifunction map is to help protecting soils that show various functions, including patrimonial functions. We therefore considered the following functions: carbon storage, water storage and infiltration, storage and filtration of contaminants, agronomic potential, biodiversity reservoir. We did not consider the support and natural resources provision functions. According to the level of knowledge on soils (local/regional/national scales, direct/indirect), we considered three mapping approaches (statistical, global, and calculation) to build function maps, and interpreted them in terms of soil function index (SFI) map. To build the soil multifunctionality quality index (SMQI) map, we crossed the various function index maps using a ponderation according to the territorial issues. These issues derive from discussions with the urban planners of the local authority and the number of functions assessed on each part of the territory (some functions not mapped in the city center). We carried out discussions with the urban planners all along the methodological development process to ensure applicability of the index map produced.
The results obtained are very satisfying considering the level of knowledge on soils. The urban planners of the local authority clearly imagine how to use both the soil function maps as well as the soil multifunctionality quality index map. We are nevertheless aware of the limits due to the use of data with different scales of validity (eg. 1 / 250 000 for pedological map; 1/10 000 for soil land-use model; statistical data on C and biodiversity at pedoclimatic scale vs national scale). The comparison with local punctual data helps verifying the degree of confidence of the maps. The methodological development is currently being adjusted and tested on other cities (in particular Marseilles and Châteauroux, France) and further discussed with urban planners at national scale. Efforts are necessary to build a wider and more precise knowledge on urban soils by gathering and sharing existing data. This implies building reference knowledge and by defining the most useful properties to acquire in a systematic way to characterize soils so as to optimise urban planning and development.
How to cite:
Leroi, T., Le Guern, C., Béchet, B., Ducommun, C., Moulin, J., Laroche, B., Duvigneau, C., Keller, C., Néel, C., Marseille, F., and Branchu, P.: Mapping soil multifunctionality for urban planning: how to deal with limited knowledge on soils?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11491, https://doi.org/10.5194/egusphere-egu2020-11491, 2020.
Katazyna Miksa, Miguel Inacio, Marius Kalinauskas, Eduardo Gomes, and Paulo Pereira
Urban sprawl is decreasing the groundwater recharge by sealing the soils. In several cases, this expansion occurs were soils have the highest quality and infiltration capacity. Soil sealing destroys the soil functions and reduces drastically the capacity to store water and regulate floods. The objective of this work is to map groundwater recharge capacity in Vilnius urban and peri-urban areas (urban atlas). To model groundwater recharge capacity, we used several variables such as lithology, geomorphology, slope, topographic wetness index, river network, tectonic faults, topographic position index, soil sand content and depth, precipitation, and land use. The model was validated using soil clay content. Drainage and tectonic faults density were calculated using the line density tool. Data was reclassified and overlaid applying the fuzzy overlay method. The results showed that the areas most urbanized and located in steeper slopes have the lowest values of groundwater recharge capacity. On the other hand, flat areas in sandy soil areas had the highest capacity. The model had an acceptable validation performance (r2=0.52).
This work was funded by the European Social Fund project LINESAM No. 09.3.3-LMT-K-712-01-0104 under grant agreement with the Research Council of Lithuania (LMTLT).
How to cite:
Miksa, K., Inacio, M., Kalinauskas, M., Gomes, E., and Pereira, P.: Mapping groundwater recharge in Vilnius urban and peri-urban area (Lithuania), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4025, https://doi.org/10.5194/egusphere-egu2020-4025, 2020.
Blandine Clozel - Leloup, Cécile Le Guern, and Vivien Baudouin
Anticipating soil contamination problems is a key issue for urban redevelopment and planning. Indeed, it is important to avoid unexpected delays and costs as well as bad image in case of unexpected pollution problem. It is also useful in order to optimize soil functions and services. In this frame, we show the interest of mapping historical (potential) sources of contamination, based on the example of (former) industrial and service activities (eg. gas station) that are a main source of contamination in the urban environment of (former) industrial countries. In particular, we present a detailed geographical information system developed in France and its several possible options.
The methodology uses the public existing inventories on (potentially) contaminated sites (basic site knowledge and point localization), completed by deeper archives searches. In this frame, we gather administrative details such as the nature of activities, their date of beginning and duration, the nature of the chemical products/materials used/created by the activities, their address and maps that are collected with great care. We then use a GIS to contour the geographical area of each site after maps adjustment and fill in the associated database. We then adapt the interpretation and visualization options according to the needs of the operating partner (urban developer, planners, city…) and the size of the studied territory. One option for instance consists in digitalizing all the known potentially contaminated sources within each site. Another option proposes an interpretation of the potentially contaminated surfaces in terms of potential contaminants.
The results consists in interactive maps synthetizing information spread in various archives since the 1800s about industrial and service activities. The territorial historic synthesis allows a gain of knowledge compared to the site-to-site approaches usually applied. We will show how this information, easily available thanks to GIS application, is already applied to set up in situ investigations programs preliminary to large redevelopment projects (eg. at district scale) or to anticipate contamination issues during street work (eg. buried infrastructure) and how it begins to be also applied for management of excavated soils.
Although it is impossible to map 100% of the former sites, the knowledge is very useful to limit contamination problems in the way it helps localizing precisely potential point-source contamination sources linked to (former) industrial and service activities. It is complementary to other knowledge on source contamination such as anthropogenic deposits that are another main source of urban soil contamination.
How to cite:
Clozel - Leloup, B., Le Guern, C., and Baudouin, V.: Mapping former industrial and service activities to anticipate contamination issues for urban planning and redevelopment, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13838, https://doi.org/10.5194/egusphere-egu2020-13838, 2020.
Abstract: The increasing atmospheric carbon dioxide (CO2) and nitrogen (N) deposition along with human activities had important effects on soil properties and influenced ecosystem service (ES) delivery. Since GFGP (Grain for Green Project) implementation in China, dominant ES in Loess Plateau such as soil conservation and carbon storage increased substantially. However, there are few researches on ecological mechanism to explain provision of multiple ES, which may result in weak theoretical foundation to support policy and management. Here, we assess the impact of different land uses (forest, shrubland, grassland, cropland and orchard) on soil properties (texture, moisture, SOC, TN, TK, TP, C:N ratio) at different depths (0-100 cm) in Yanhe watershed (China). The results showed that soil texture sand and silt content were significantly higher in shrubland than in orchard and cropland, while clay content was significantly higher in forest. No differences were observed in soil moisture. Similar results were identified in TP and TK. SOC was significantly higher in forest soils compared to other land uses while TN had the lowest values among land uses, which cause carbon storage ES increased after transforming cropland to forest and grassland. Though there were significant differences in SOC and TN, the C:N ratio was significantly consistent in different depths and land use types. In addition, Redundancy analysis revealed that altitude and precipitation were the factors that influenced more soil properties.
How to cite:
Yang, S., Zhao, W., and Pereira, P.: Effects of depth and land use on vertical soil properties and their contributions to ecosystem services in Yanhe watershed, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-954, https://doi.org/10.5194/egusphere-egu2020-954, 2019.
Shyamal Karmakar, Md. Enamul Hoque, M M Abdullah Al Mamun, Mohammad Ayub Parvez, Srijon Datta, Md. Nazrul Islam, Mir Enamul Karim, and Mohammad Shafiul Alam
Halda River originated and ends inside Bangladesh, is a unique natural carp spawning habitat that underwent a massive channel modification, intensive land use and land cover changes across its basin both in the upstream and downstream area over the decades. The carp fish breeding habited is heavily disturbed that marked by a significant reduction in fish spawning in recent years. The fish habitat of this river is reported as critically endangered in many studies. However, these problems are not studied in a hydrological perspective apart from fish spawning characterization and water quality nexus. We have studied the flow regime of the catchment for different seasons and its effects on water quality, siltation, and erosion of this river at 12 cross-sections at the upper course and middle course. Water level and discharge data that are available from the regulatory authority, Bangladesh Water Development Board for the last 40 years at an upstream cross-section and rainfall data at 4 stations of the catchment were studied and integrated to understand nutrient load using QSWAT. The upstream-downstream linkage is heavily regulated followed by the construction of an earthen dam and rubber dam on its major tributaries at upstream for irrigation to the agricultural land that was revealed from this study and field visits. Moreover, basin land-use and land-cover change would have a significant contribution to sediment dynamics eventually causing siltation and erosion in downstream cross-section. The increase in agricultural land that altered forest vegetation would affect runoff characteristics and water quality. We have reported that the change in sediment load and siltation in its downstream and at different hydraulic structure points (here sluice gate, irrigation canals, and embankments) would be attributed to land-use change and flow regulation. This study reports the relationship to the hydraulic response viz. discharge, the water level of this river system to the catchment land use and siltation. Floods are more likely to occur in the downstream region compared to the upstream region in the same hydro-meteorological regime in this basin as it revealed from the river section changes over time.
How to cite:
Karmakar, S., Hoque, Md. E., Mamun, M. M. A. A., Parvez, M. A., Datta, S., Islam, Md. N., Karim, M. E., and Alam, M. S.: Catchment land use and river morphological changes effect on flow and pollution load of Halda River: implication in integrated river management, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1109, https://doi.org/10.5194/egusphere-egu2020-1109, 2019.
Rory Walsh, Carla Ferreira, William Blake, Sam Higton, and Antonio Ferreira
An ability to identify and quantify changes in sediment sources and erosion within catchments would be of great use for landscape managers and planners. This is particularly the case in peri-urban catchments, which are characterized by complex and dynamically changing land-use mosaics – and where today’s planning decisions may be crucial as regards avoiding or exacerbating erosional, water quality and flooding problems. This study explores the potential for a sediment fingerprinting approach to provide a cost-effective way of assessing changes in sediment sources within a small peri-urban catchment. The study focuses on the Ribeira dos Covões catchment (6.2 km2), on the outskirts of Coimbra in central Portugal. The climate is humid Mediterranean and the geology is 56% sandstone, 41% marly limestone and 3% alluvium. Current land-use is 56% woodland, 4% agricultural and 40% urban (mainly residential, but also a recently constructed enterprise park (5%) and major highway (1%)). Recent urbanization has largely occupied former agricultural land. The study adopts a multi-proxy sediment fingerprinting approach, based on geochemical (elemental) characterization of fluvial fine bed-sediment and soil samples, using a Niton x-ray fluorescence elemental analyser. Sampling of fluvial sediment was carried out at 33 sites within the stream network (including all significant tributaries, downstream sites and the catchment outlet). Samples were collected in July 2018 and November 2018 following contrasting ‘late wet season’ and ‘end of dry season’ events. In addition, in July 2018 composite samples of potential sediment sources were collected, including (i) soil surface (0-2cm) samples at 64 representative locations, (ii) 17 samples from eroding channel margin sites, and (iii) 15 samples of road sediment. All samples were sieved to obtain <63µm, 63-125µm, 125-250 µm and 250-2000µm fractions, where the <63µm fraction was taken to represent suspended sediment. The elemental geochemistry of each sample fraction was derived using the XRF analyser. Differences (and similarities) in geochemical signatures between the various tributaries and the various potential sources were assessed using a range of statistical techniques. Bayesian unmixing models were used in a hierarchical (confluence-based) fashion to assess the contributions of different sub-catchments to downstream sites including the catchment outlet. Modelling results were then compared with relative contributions for three previously analysed storm events of 2012-2015, at which time construction activities had been more active. Modelling results for the two 2018 events were also validated by comparing them with independent suspended sediment records collected at five locations on the principal tributaries and at the catchment outlet. Overall, the modelling was successful in indicating and quantifying significant changes in sediment sources through time within the catchment. Reasons as to why sediment fingerprinting was successful in this case are then examined and discussed, in part drawing comparisons with the findings from a parallel sediment fingerprinting study of changing sources in the dynamically changing partly logged rainforest, partly oil palm Brantian catchment in Sabah, Malaysian Borneo. The potential for a simple sediment fingerprinting methodology to be developed for more widespread use by urban/environmental managers and planners is then explored.
How to cite:
Walsh, R., Ferreira, C., Blake, W., Higton, S., and Ferreira, A.: Exploring the potential for using hierarchical sediment fingerprinting as an urban management tool in monitoring changing sediment sources, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18003, https://doi.org/10.5194/egusphere-egu2020-18003, 2020.
Luis Pinto, Carla Ferreira, Paulo Pereira, and António Ferreira
The Ecosystem Services provided by Urban Green and Blue Infrastructures (UGBI) are considered fundamental to improve the resilience of urban areas against the growing challenges of global warming. Indicators regarding the relevance and efficiency of UGBI are abundant, but they have been mainly focused on environmental related aspects, while the socio-cultural aspects of UGBI are still under represented. Considering the socio-cultural and recreational aspects, studies show that UGBI can significantly contribute for quality of life, sense of place, social interactions, physical wellbeing, learning, and other intangibles. A major and growing portion of recreation is indeed “nature-based", involving interactions with the natural environment. For these types of activities, different characteristics of the environment influence people’s decisions about where, when, and how to recreate. But fine-scale data collection regarding these aspects are usually site specific, and time and labour intensive. Wood et al. (2013) showed that the number of users who visit a location annually is related to the number of photographs taken in the same area and uploaded to the flickr database. Using the InVEST recreation model, this work aims to (1) test social media photo posts on Flickr as an indicator for the use of UGBI, and to (2) analyze its potential correlation with a set of cultural and recreational equipment in and around UGBI units. Two different periods are analyzed, with the intention to identify and evaluate the differences introduced with the implementation of a major city park near the river Mondego. The results show that the presence of the river and the proximity to the city center - with its old town - are major factors in the recreational use of the UGBI. They also show that the implementation of new UGBI units - under the form of a city park - can change the usage pattern of an area.
How to cite:
Pinto, L., Ferreira, C., Pereira, P., and Ferreira, A.: Analyzing social media photo posts distribution as a potential indicator for UGBI user preferences: the case of Coimbra, Portugal, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20417, https://doi.org/10.5194/egusphere-egu2020-20417, 2020.