scholarly journals Operational tools to help stakeholders to protect and alert municipalities facing uncertainties and changes in karst flash floods

2015 ◽  
Vol 370 ◽  
pp. 201-208 ◽  
Author(s):  
V. Borrell Estupina ◽  
F. Raynaud ◽  
N. Bourgeois ◽  
L. Kong-A-Siou ◽  
L. Collet ◽  
...  
Keyword(s):  
Land Use ◽  
Real Time ◽  
Land Use Changes ◽  
Extreme Rainfall ◽  
Flash Floods ◽  
Uncertain Information ◽  
Extreme Rainfall Events ◽  
Flood Peak ◽  
Planning Decisions ◽  
Graphical Tool

Abstract. Flash floods are often responsible for many deaths and involve many material damages. Regarding Mediterranean karst aquifers, the complexity of connections, between surface and groundwater, as well as weather non-stationarity patterns, increase difficulties in understanding the basins behaviour and thus warning and protecting people. Furthermore, given the recent changes in land use and extreme rainfall events, knowledge of the past floods is no longer sufficient to manage flood risks. Therefore the worst realistic flood that could occur should be considered. Physical and processes-based hydrological models are considered among the best ways to forecast floods under diverse conditions. However, they rarely match with the stakeholders' needs. In fact, the forecasting services, the municipalities, and the civil security have difficulties in running and interpreting data-consuming models in real-time, above all if data are uncertain or non-existent. To face these social and technical difficulties and help stakeholders, this study develops two operational tools derived from these models. These tools aim at planning real-time decisions given little, changing, and uncertain information available, which are: (i) a hydrological graphical tool (abacus) to estimate flood peak discharge from the karst past state and the forecasted but uncertain intense rainfall; (ii) a GIS-based method (MARE) to estimate the potential flooded pathways and areas, accounting for runoff and karst contributions and considering land use changes. Then, outputs of these tools are confronted to past and recent floods and municipalities observations, and the impacts of uncertainties and changes on planning decisions are discussed. The use of these tools on the recent 2014 events demonstrated their reliability and interest for stakeholders. This study was realized on French Mediterranean basins, in close collaboration with the Flood Forecasting Services (SPC Med-Ouest, SCHAPI, municipalities).

Quantifying Consequences of Land Use and Rainfall Changes on Maximum Flood Peak in the Lower Nam Phong River Basin

2014 ◽  
Vol 931-932 ◽  
pp. 791-796 ◽  
Author(s):  
Kittiwet Kuntiyawichai ◽  
Winai Sri-Amporn ◽  
Chadchai Pruthong
Keyword(s):  
Land Use ◽  
River Basin ◽  
Land Use Changes ◽  
Correlation Coefficients ◽  
Extreme Rainfall ◽  
Flood Management ◽  
Return Periods ◽  
Flood Peak ◽  
Flood Impacts ◽  
Projected Changes

When the severity of exposure to flood is being addressed, several related concerns have always been raised to draw attention on a growing flood threat. In relation to this, the extraordinary insight into the seriousness of land use and rainfall changes that could greatly exacerbate flood impacts would need to be highlighted. The importance of the aforementioned issue lies in the main objective of quantifying consequences of how changes in land use and rainfall affect the hydrological processes in the lower Nam Phong River Basin. The use of Hydrologic Modeling System (HEC-HMS) simulation model would add robustness and predictability to the overall results. It was apparent from the calibration and validation processes that there are reasonably close agreement between observed and simulated discharges at Ban Nong Hin gauging station (E.22A), with good correlation coefficients (ENS= 0.78, r2= 0.81 and ENS= 0.77, r2= 0.82, respectively). Thereafter, different what-if scenarios were conducted to determine impacts of land use changes in 2001, 2011 and 2057 and extreme rainfall with different return periods of 10-, 50-and 100-years on hydrological responses. A slight increase in peak flows were equal to 4% and 1%, as a consequence of the change from 2001 land use conditions to 2011 and 2057, respectively. Conversely, a large increase in peak discharges was expected to be 13%, 20% and 27% when the 2001 rainfall event was adjusted to the projected changes in rainfall corresponding to 10-, 50-and 100-year return periods, respectively. In brief, insignificant relation between hydrological response and land use changes was obviously found, but it was of particular significance due to changes in rainfall extremes. Taken together, obtained findings can then be used as a baseline for water resources planning, development and management, as well as flood management perspective.

scholarly journals Extreme Rainfall in the Mediterranean: What Can We Learn from Observations?

2013 ◽  
Vol 14 (3) ◽  
pp. 906-922 ◽  
Author(s):  
N. Rebora ◽  
L. Molini ◽  
E. Casella ◽  
A. Comellas ◽  
E. Fiori ◽  
...  
Keyword(s):  
Extreme Rainfall ◽  
Flash Floods ◽  
Rain Gauge ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Life Threatening ◽  
The Mediterranean ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Ground Effects

Abstract Flash floods induced by extreme rainfall events represent one of the most life-threatening phenomena in the Mediterranean. While their catastrophic ground effects are well documented by postevent surveys, the extreme rainfall events that generate them are still difficult to observe properly. Being able to collect observations of such events will help scientists to better understand and model these phenomena. The recent flash floods that hit the Liguria region (Italy) between the end of October and beginning of November 2011 give us the opportunity to use the measurements available from a large number of sensors, both ground based and spaceborne, to characterize these events. In this paper, the authors analyze the role of the key ingredients (e.g., unstable air masses, moist low-level jets, steep orography, and a slow-evolving synoptic pattern) for severe rainfall processes over complex orography. For the two Ligurian events, this role has been analyzed through the available observations (e.g., Meteosat Second Generation, Moderate Resolution Imaging Spectroradiometer, the Italian Radar Network mosaic, and the Italian rain gauge network observations). The authors then address the possible role of sea–atmosphere interactions and propose a characterization of these events in terms of their predictability.

scholarly journals Integrating Land-Use and Renewable Energy Planning Decisions: A Technical Mapping Guide for Local Government

2020 ◽  
Vol 9 (5) ◽  
pp. 324
Author(s):  
Jiaao Guo ◽  
Victoria Fast ◽  
Philip Teri ◽  
Kirby Calvert
Keyword(s):  
Land Use ◽  
Renewable Energy ◽  
Land Use Planning ◽  
Local Governments ◽  
Emission Reduction ◽  
Land Use Changes ◽  
Planning Decisions ◽  
Environmentally Sensitive ◽  
Utility Scale

Land-based, utility-scale renewable energy (RE) systems using wind or solar resources to generate electricity is becoming a decisive solution to meet long-term carbon emission reduction goals. Local governments are responding in kind, by adopting their own goals and/or establishing policies to facilitate successful implementations of RE in their jurisdiction. One factor to successful RE development is to locate the most suitable lands, while continuing to sustain land-based economies and ecosystem services. Local governments often have limited resources; and this is especially true for small, land-constrained local governments. In this paper, we illustrate how a standardized RE technical mapping framework can be used by local governments to advance the implementation of RE in land-constrained areas, through a case study in the Town of Canmore, Alberta. Canmore has a limited municipal area surrounded by the Canadian Rockies, along with complex land-use bylaw and environmentally sensitive habitats. This mapping framework accounts for these conditions as it considers theoretical resources, technically recoverable lands, legally accessible lands, and the spatial capital cost of connecting new RE facilities. Different land-use planning scenarios are considered including changing setback buffers and expanding restrictions on development to all environmentally sensitive districts. The total RE potentials are then estimated based on the least-conflict lands. Technically speaking, even under restrictive land suitability scenarios, Canmore holds enough land to achieve ambitious RE targets, but opportunities and challenges to implementation remain. To eventually succeed in its long-term emission reduction goal, the most decisive step for Canmore is to balance the growth of energy demands, land-use changes, and practicable RE development. Mapping systems that can study the influence of land-use planning decisions on RE potential are critical to achieving this balance.

scholarly journals The influence of deforestation and anthropogenic activities on runoff generation

2017 ◽  
Vol 63 (No. 6) ◽  
pp. 245-253 ◽  
Author(s):  
Khaleghi Mohammad Reza
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Anthropogenic Activities ◽  
Land Use Changes ◽  
Hydrologic Model ◽  
Geographical Information ◽  
Runoff Generation ◽  
Mazandaran Province ◽  
Gis And Remote Sensing ◽  
Flood Peak

In recent decades, due to rapid human population increases and in its results, destructive effects of anthropogenic activities on natural resources have become a great challenge. Land use and vegetation are important factors in soil erosion and runoff generation. This study was performed to assess the effects of different amounts of forest cover on the control of runoff and soil loss in the Talar basin, which is located in Mazandaran province, using a runoffrainfall model, geographical information system (GIS) and remote sensing (RS) to determine the hydrologic effects of deforestation on the Talar watershed (north of Iran). A runoff-rainfall model has been presented using GIS (HECGeoHMS) and hydrologic model (HEC-HMS). Land use changes (deforestation) and anthropogenic activities (roads and impervious surfaces development) were evaluated using RS techniques and satellite images. We used the Soil Conservation Service and Curve Number methods for hydrograph simulation and runoff estimation, respectively. First, a model was performed and optimized. Afterward, the optimized model was evaluated by other six events of floods (model validation). According to the obtained results, the runoff generation potential has been increased in the Talar watershed due to deforestation during the last forty years. Land use changes cause an increase in runoff volume and flood peak discharge.

scholarly journals A GIS-BASED PROCEDURE FOR MEASURING THE EFECTS OF THE BUILT ENVIRONMENT ON URBAN FLASH FLOODS

2016 ◽  
Vol 11 (3) ◽  
pp. 110-125 ◽  
Author(s):  
Yan Li ◽  
Chunlu Liu
Keyword(s):  
Land Use ◽  
Built Environment ◽  
Urban Areas ◽  
Flood Hazard ◽  
Land Use Changes ◽  
Flash Floods ◽  
Flood Inundation ◽  
Storm Events ◽  
Severe Problem ◽  
The Impact

Urban flooding has been a severe problem for many cities around the world as it remains one of the greatest threats to the property and safety of human communities. In Australia, it is seen as the most expensive natural hazard. However, urban areas that are impervious to rainwater have been sharply increasing owing to booming construction activities and rapid urbanisation. The change in the built environment may cause more frequent and longer duration of flooding in floodprone urban regions. Thus, the flood inundation issue associated with the effects of land uses needs to be explored and developed. This research constructs a framework for modelling urban flood inundation. Different rainfall events are then designed for examining the impact on flash floods generated by land-use changes. Measurement is formulated for changes of topographical features over a real time series. Geographic Information System (GIS) technologies are then utilised to visualise the effects of land-use changes on flood inundation under different types of storms. Based on a community-based case study, the results reveal that the built environment leads to varying degrees of aggravation of urban flash floods with different storm events and a few rainwater storage units may slightly mitigate flooding extents under different storm conditions. Hence, it is recommended that the outcomes of this study could be applied to flood assessment measures for urban development and the attained results could be utilised in government planning to raise awareness of flood hazard.

Questioning models of land degradation in arid and semi-arid regions: a re-assessment based on evidence from northern Jordan

2020 ◽  
Author(s):  
Bernhard Lucke
Keyword(s):  
Land Use ◽  
Land Degradation ◽  
Arid Regions ◽  
Extreme Rainfall ◽  
Minor Role ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Erosion Risk ◽  
Semi Arid ◽  
Northern Jordan

<p>Assessments of land degradation in arid and semi-arid regions frequently employ models calculating annual erosion rates from the size of sediment bodies, assuming grain-by-grain transport and constant processes of deposition. It is often attempted to connect historic sediment bodies to past land use and climate by correlations with demographic estimates and reconstructions of past precipitation averages. In addition, mass transport is often equalled with soil loss and fertility degradation, based on the idea that humus-rich topsoils store the greatest part of soil nutrients. However, such concepts are based on premises transferred from temperate regions, and their suitability for arid and semi-arid regions is questionable. For example, dryland soils usually contain very small amounts of organic matter, which means that their fertility is mostly a function of texture, and a limited loss of topsoil is rather irrelevant for agricultural productivity. Part of the sediments deposited in valleys come from soft, easily erodible rocks, which means that they reflect slope denudation and not soil erosion. As well, erosion-sedimentation processes do often not take place by continuous transport of single grains. This is illustrated with a valley fill in northern Jordan: sediments were deposited discontinuously, mainly by slumping and earth flows, and the largest parts of the fill accumulated in time frames of ~100 years during the two Little Ice Ages (6<sup>th</sup> and 14<sup>th</sup> century AD/CE). Due to a dominance of smectites, the clay-rich Red Mediterranean Soils in the vicinity shrink and form cracks during the dry period. Because of the cracks and underlying limestone karst, they can swallow strong rains without erosion risk. However, when water-saturated, soils expand and may move in slump flows. Soil-covered geoarchaeological features like a buried ancient cemetery illustrate that such viscous flows created new land surfaces, sealing cavities but not filling them. This suggests a major role of rare but intense rainfall events in erosion-deposition processes. Analogies with modern rainfalls, including record levels of precipitation during the winter 1991/1992, indicate that levels of soil moisture triggering similar slump flows have not been reached during times of modern rainfall monitoring. That ancient land use played a minor role for erosion is supported by intense surveys of archaeological material on fields surrounding the valley, which indicate that the periods of most intensive land use coincided with very limited sediment deposition. Concepts of land degradation in semi-arid and arid regions should be reconsidered, respecting the more irregular environmental setting, the specific soil properties, and traditional land use systems which evolved in constant adaptation to this environment. Rare but extreme rainfall events as potential main drivers of land degradation should be considered more: they are difficult to control or mitigate, but may increase due to climate change.</p>

scholarly journals Interactions between deforestation, landscape rejuvenation, and shallow landslides in the North Tanganyika – Kivu Rift region, Africa

2020 ◽  
Author(s):  
Arthur Depicker ◽  
Gerard Govers ◽  
Liesbet Jacobs ◽  
Benjamin Campforts ◽  
Judith Uwihirwe ◽  
...  
Keyword(s):  
Slope Failure ◽  
Land Use Changes ◽  
Extreme Rainfall ◽  
Google Earth ◽  
Shallow Landslides ◽  
Extreme Rainfall Events ◽  
Landslide Activity ◽  
Erosion Rates ◽  
The North ◽  
The Impact

Abstract. Deforestation increases landslide activity over short, contemporary timescales. However, over longer timescales the location and timing of landsliding is controlled by the interaction between uplift and fluvial incision. Yet, the interaction between (human-induced) deforestation and landscape evolution has hitherto not been explicitly considered. We address this issue in the North Tanganyika-Kivu Rift region (East African Rift). In recent decades, the regional population has grown exponentially and the associated expansion of cultivated and urban land has resulted in widespread deforestation. On a much longer time scale, tectonic uplift has forged two parallel mountainous Rift shoulders that are continuously rejuvenated through knickpoint retreat, enforcing topographic steepening. In order to link deforestation and rejuvenation to landslide erosion, we compiled an inventory of nearly 8,000 recent shallow landslides in Google Earth© imagery from 2000–2019. To accurately calculate landslide erosion rates, we developed a new methodology to remediate inventory biases linked to the spatial and temporal inconsistency of this satellite imagery. We find that erosion rates in rejuvenated landscapes are roughly 40 % higher than in the surrounding relict landscapes, upstream of retreating knickpoints and outside of the Rift shoulders. This difference is due to the generally steeper relief in rejuvenated landscapes which more than compensates for the fact that rejuvenated slopes, when compared to similarly angled slopes in relict zones, often display a somewhat lower landslide erosion rate. These lower rates in the rejuvenated landscapes could be the result of a drier climate, the omission of earthquake-induced landslide events in our landslide inventory, and potentially a smaller regolith stock. More frequent extreme rainfall events in the relict zones, and possibly the presence of a thicker regolith, cause a stronger landslide response to deforestation compared to rejuvenated landscapes. Overall, deforestation initiates a landslide peak that lasts approximately 15 years and increases landslide erosion by a factor 2 to 8. Eventually, landslide erosion in deforested land falls back to a level similar to that observed under forest conditions, most likely due to the depletion of the most unstable regolith. Landslides are not only more abundant in rejuvenated landscapes but are also smaller in size, which may be a consequence of the seismic activity that fractures the bedrock and reduces the minimal critical area for slope failure. With this paper, we highlight the importance of considering the geomorphological context when studying the impact of recent land use changes on landslide activity.

scholarly journals Runoff evolution according to land use change in a small Sahelian catchment

2011 ◽  
Vol 8 (1) ◽  
pp. 1569-1607 ◽  
Author(s):  
L. Descroix ◽  
M. Esteves ◽  
K. Souley Yéro ◽  
J.-L. Rajot ◽  
M. Malam Abdou ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Water Cycle ◽  
Land Use Changes ◽  
Strong Increase ◽  
Rainfall Runoff ◽  
Runoff Water ◽  
Flood Peak ◽  
Water Transmission ◽  
Sahel Region

Abstract. Significant land use changes have been observed in West Africa, particularly in the Sahel region where climatic and demographic factors have led to a rise in cultivated areas, in recent decades. These changes caused strong modifications in the water cycle and in river regimes. By comparing the rainfall-runoff relationships for two periods (1991–1994 and 2004–2010) in two small neighbouring catchments (approx. 0.1 km2 each) of the Sahel, this study highlights the different hydrological consequences of land use change, particularly vegetation clearing and the consequent degradation of topsoil. Runoff increased in the upper basin, while it decreased in the lower basin, due to a strong increase in in-channel infiltration. Flood peak durations have become shorter in the downstream part of the catchment due to the huge increase of runoff water transmission losses within the gullies. Further study will consist of equipping one of the catchments with anti-erosion devices (mainly "half-moons" and terraces) in order to evaluate the influence of anti-erosion devices on runoff and suspended load.

scholarly journals FLOOD-PREPARED: A NOWCASTING SYSTEM FOR REAL-TIME IMPACT ADAPTION TO SURFACE WATER FLOODING IN CITIES

2020 ◽  
Vol VI-4/W2-2020 ◽  
pp. 9-15
Author(s):  
S. L. Barr ◽  
S. Johnson ◽  
X. Ming ◽  
M. Peppa ◽  
N. Dong ◽  
...  
Keyword(s):  
Surface Water ◽  
Real Time ◽  
Situational Awareness ◽  
Road Traffic ◽  
Extreme Rainfall ◽  
Water Flooding ◽  
Urban Systems ◽  
Transport Systems ◽  
Extreme Rainfall Events ◽  
On The Road

Abstract. Extreme rainfall events pose an ever increasing threat to cities due to the potential for surface water flooding resulting in damage to properties and major disruption of transport systems. Modern sensor networks offer enormous potential for the real-time monitoring of urban systems and potentially allow improved situational awareness of impeding hazards and their impacts such as flooding. However, monitoring in itself is not enough if we are to be able to adapt in in real-time to hazards. Systems are required that allow analytics and models, that feed of real-time observations, to make predictions of impacts and suggest adaption options ahead of the hazard event. The Flood-PREPARED project is developing a system for real-time adaption to surface water flooding. The system comprises of advanced spatiotemporal models of rainfall, surface water flooding and road traffic impacts. These models are linked and orchestrated within into a Big Data workflow that allows events to be simulated using emerging rainfall data recorded by a short range weather radar. This approach allows nowcasting to be undertaken where predictions of surface water inundation and impacts on the road network can be predicted ahead of the rainfall event reaching the city; thus providing the ability for an improved adaptive response to the actual event.

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