1,721,014 research outputs found
Geomorphological mapping in urban area: changes in stream network of Genoa historical city (Liguria, Italy)
No full textAll over the centuries the expansion of residential, industrial and harbour settlements of Genoa city have impacted on geomorphological processes along the narrow coastal plains and surrounding slopes. Mostly the drainage network has been strongly modified by rectification, diversion and culvert interventions, causing critical flow section reductions (Limoncelli & Marini, 1971; Brandolini & Sbardella, 2001). These morphological changes resulted in increasing geo-hydrological hazard and, consequently, Genoa municipality has been affected by even more recurrent floods (Brandolini et al., 2012; Faccini et al., 2015).
This research focuses the attention of Genoa Old Port and surrounding area - where historically town developed - with the aim to reconstruct the former stream network, culverted since Middle Ages and currently almost totally underground. The final goal is to perform a G.I.S. based geomorphological map applying the proposal of legend in testing progress within AIGeo.
The study is based on comparison among ancient and recent maps, aerial photointerpretation, historic archives data, geotechnical investigations conducted for engineering purposes and field survey.The area, with an extent of about 8.5 km2, is characterized by several catchments, from W to E: San Bartolomeo (0.49 km2), San Lazzaro (1.33 km2), San Teodoro (0.54 km2), Lagaccio (2.36 km2), Sant’Ugo (0.8 km2), Carbonara (1.1 km2), Sant'Anna (0.72 km2) and Torbido (1.17 km2). These watercourses, modified over time in channels and nowadays with a man-made hydraulic network catchments, flow culverted under the streets of the old town (Bixio et al., 2015).
A more detailed knowledge of these underground streams could contribute to a better evaluation of geo-hydrological hazards and planning of risk mitigation measures for supporting Basin Master Plan of Genoa metropolitan are
Geomorphology in urban coastal environment: a case study from Rapallo city (Liguria, Italy)
No full textRapallo, with 30,000 inhabitants, is an important seaside tourist resort in the Eastern ligurian coast. It is internationally known since the beginning of the 20th century for elite tourism. Following the development of mass tourism, above all during 1960s and
1970s, the whole municipality has been affected by an intense urbanization – mainly due to construction of homes for holiday – which have strongly modified either the former landforms of the flood plain, either the surrounding slopes up to 150-200 m
a.s.l. The area covered by urbanization has increased from approximately 45 ha in the early twentieth century, up to 175 ha in 1957, 600 ha in 1978 and 650 ha nowadays. This research is aimed to reconstruct the morphological transformations in a coastal environment, considering the historical changes due to human interventions and the related impact on geomorphological processes occurred since the 18th century. The study is based on field survey and on the interpretation and comparison among
ancient and recent maps, aerial stereographic photos and orthophotos, on historic archive data, on drill analysis by several geotechnical investigations conducted on coastal-flood plain for civil and environmental purposes
Geomorphological mapping in Ligurian coastal areas: preliminary results of Genoa old port and Rapallo city (Liguria, Italy)
No full textThe geological layout of Landscape Master Plan: an example from Liguria (Italy)
No full textAfter more than 25 years since the first studies, the Landscape Master Plan of Liguria has contributed to maintaining the cultural and natural landscape. The current plan is made by three descriptive layouts and related regulations: the settlement and botanical settings represent the features of the landscape linked to buildings and vegetation. The geomorphological layout
shows only the regulations, without any reference to Earth surface processes and landforms. This research suggests a methodology aiming at providing the plan with an engineering geologic suitable layout with the other settings. We
propose eight geomorphological landscape units: all of them are connected with Earth surface dynamic factors, including man-made landforms and geodiversity values. A double key to the interpretation of this geo-map is suggested. The capital letters corresponding to regulations are maintained; we have inserted a new label linked to the geomorphological landscape unit. This
updating may be integrated in the review processes of the Landscape Master Plan already started by Regional Authority
The role of historical agricultural terraces in geo-hydrological risk reduction: a case study from the Bisagno Stream catchment (Genoa, Italy)
No full textTerraces, traditionally sustained by dry stonewalls, occupy about thirty percent of the territory of Liguria. If constantly maintained, they effectively contribute to slow down the natural slope erosion. When no longer managed, terraces are recognized as one of the reasons for increased geomorphological risk along the slopes and, consequently, at the bottom of the valley. ThisstudyconcernstheterracedlandscapesoftheBisagnoStreamcatchment,internationallyknownfortherecent and recurring floods which affected the city of Genoa. The Bisagno Stream catchment is an example of historical evolution of the territory both in terms of land use change and geo-hydrological risk. The catchment, whose highest point is Mount Candelozzo (1034 m), has a total area of 95 km2. In its terminal stretch the stream flows across the eastern part of Genoa city centre. It is a typical valley of the Genoa metropolitan area, with steep slopes and short times of concentration. Here the signs of the tragic floods which have affected the area since 1970 are still visible. The most recent and tragic geo-hydrological event in Liguria took place in the Bisagno Valley in October 2014. The study was carried out with a multi-temporal comparison of the terraced areas using aerial photographs and regional cartographic information. A further step will involve the analysis and classification of the terraces based ontheirmaintenanceconditionandhydrogeologicaleffectiveness,usingsomerepresentativeareasofthevalleyas cases study. The comparison between the distribution of terraces in the Bisagno valley and applied geomorphological cartography suggests the need of measures to reduce the risk according to a suitable set of priorities, including the recovery of the terraced areas and connected structures aimed to limit the accumulation of solid material along the main waterway
Urban Geomorphology in Coastal Environment: Man-Made Morphological Changes in a Seaside Tourist Resort (Rapallo, Eastern Liguria, Italy)
No full textAbstract
This research focuses on the reconstruction of the morphological modifications of the coastal floodplain of Rapallo (Eastern Liguria, NW Italy) due to human intervention since the eighteenth century. By the second half of the nineteenth century Rapallo became a popular tourist destination: as a consequence, the urban development of the floodplain started and became very intense after Second World War, strongly modifying former landforms.
The study was carried out using multi-temporal cartographic and photographic comparison, the analysis of geo-thematic cartography and documentation from the Basin Master Plan and the town plan of Rapallo, the interpretation of cores from regional database and field data from direct urban surveys. Man-made landforms were mapped and classified using the new geomorphological legend which is in progress in the framework of the Working Groups on “Cartography” and “Urban Geomorphology” of the Italian Association of Physical Geography and Geomorphology (AIGEO).
The main significant morphological changes were stream diversions and channeling, excavations and filling, quarry activities, embankments along the shoreline and overurbanization. Human interventions, in addition to local geomorphological and climate features, increased flood hazard and risk, which historically affected the city of Rapallo.</jats:p
The Bisagno stream catchment (Genoa, Italy) and its major floods: geomorphic and land use variations in the last three centuries
No full textThe city of Genoa (Liguria, Italy) and the Bisagno Valley are affected by frequent floods, often with loss of human lives. Historically characterised by high flood hazards, the Bisagno Valley was recently affected by a flood event on 9 October 2014, less than three years after the tragic flood event of 4 November 2011 when six people died, including two children. In the last 50 years, four destructive floods occurred in the Bisagno Valley, in addition to some other events that caused significant damage and economic losses.This paper examines the three largest flood events in terms of intensity and ground effects which affected the Bisagno Valley in the last three centuries: the flood of 25 October 1822, well documented by contemporary sources, the flood of 8 October 1970, undoubtedly the most tragic on record, and the very recent event of 9 October 2014. For this purpose scientific and historical-geographical methodologies were adopted, the latter particularly useful for the reconstruction of the flood event of 1822 and the landscape history of the Bisagno Valley in the nineteenth century.This comparison shows that the Bisagno Valley is characterised by climatic and landform features that have been making the flood events historically common in the area. However, recent climate change and land-use variations, including some major modifications of the catchment basin, have progressively determined a decrease of the concentration time and an increase of runoff, solid transport, and flood hazard. Consequently, in recent decades a growth in the number of flood events occurred, to the extent that the Bisagno today is a famous case study on an international scale
The role of citizen science in assessing the spatiotemporal pattern of rainfall events in urban areas: a case study in the city of Genoa, Italy
No full text<jats:p>Abstract. Climate change in the Mediterranean region is manifesting itself as an increase in average air temperature and a change in the rainfall regime: the value of cumulative annual rainfall generally appears to be constant, but the intensity of annual rainfall maxima, between 1 and 24 h, is increasing, especially in the period between late summer and early autumn. The associated ground effects in urban areas consist of flash floods and pluvial floods, often in very small areas, depending on the physical-geographical layout of the region. In the context of global warming, it is therefore important to have an adequate monitoring network for rain events that are highly concentrated in space and time. This research analyses the meteo-hydrological features of the 27 and 28 August 2023 event that occurred in the city of Genoa, Italy, just 4 d after the record maximum air temperature was recorded: between 19:00 and 02:00 UTC almost 400 mm of rainfall was recorded in the eastern sector of the historic centre of Genoa, with significant ground effects such as flooding episodes and the overflowing of pressurised culverts. Rainfall observations and estimates were made using both official or “authoritative” networks (rain gauges and meteorological radar) and rain gauge networks inspired by citizen science principles. The combined analysis of observations from authoritative and citizen science networks reveals, for the event analysed, a spatial variability of the precipitation field at an hourly and a sub-hourly timescale that cannot be captured by the current spatial density of the authoritative measurement stations (which have one of the highest densities in Italy). Monthly total rainfall and short-duration annual maximum time series recorded by the authoritative rain gauge network of the Genoa area are then analysed. The results show significant variation even at distances of less than 2 km in the average rainfall depth accumulated over sub-hourly duration. Extreme weather monitoring activity is confirmed as one of the most important aspects in terms of flood prevention and protection in urban areas. The integration between authoritative and citizen science networks can prove to be a valid contribution to the monitoring of extreme events.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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