Session 21 - Hydrology and water resources management

[CEST2019_00459] Flood Risk Management: past and future
by Venables J.

Based on her long involvement in water and sustainability – flood risk management, water and wastewater engineering, and water resources – Jean Venables will initially review how engineers and society have tried to deal with water in the environment. She will address recent developments in approaches such as catchment management, and integration of approaches for dealing with potable water supply, droughts and flooding. It is also important to consider how to both mitigate and adapt to climate change and its predicted effects. Jean will then address the very wide range of issues and considerations for flood risk management, including natural processes, environmental considerations, spatial planning, warning systems, preparedness, sustainability and engineered hard defences. A limiting factor can often be the availability of funding as there are competing priorities in any country and there has to be a system of prioritisation of actions. Finally, Jean will address the future and how we can improve our integration of approaches to these challenges, especially in the context of the predicted effects of climate change. At the same time, we still need to recognise, and educate the general public about, the fact that, whilst we can reduce the risk of flooding, we cannot (ever) eliminate it.

Session: 21, Room: C, at Fri, 09/06/2019 - 09:00 to 09:30
Oral presentation in Hydrology and water resources management

Flood risk prediction requires consistent and accurate sensor measurements, usually provided from traditional in-situ environmental monitoring systems. Crowd-sourced data can complement these official data sources, allowing authorities to improve and fill gaps in the hazard assessment process. However, collecting this information from volunteers, with no technical knowledge and while using low-cost equipment such their smartphones and tablets, raises the question of quality and consistency. To alleviate this barrier two tools were developed in the context of H2020 Scent project (grant agreement No. 688930). The Water Level Measurement Tool uses image recognition techniques to extract the water level from images containing a measuring tape. The Water Velocity Calculation Tool uses video processing algorithms to extract the water surface velocity from a video containing a pre-defined floating object moving on the surface of a water body. Each extracted measurement is accompanied by a degree of trust. The tools have been designed so that a high degree of trust can be achieved from images and videos taken from regular smartphones. The crowdsourced river measurements are used to develop improved flood models with a dramatically reduced cost as both the measuring tapes and the floating object are low-cost and re-usable while effectively covering large areas of interest.

Session: 21, Room: C, at Fri, 09/06/2019 - 10:15 to 10:30
Oral presentation in Hydrology and water resources management

Determination of runoff and related design discharges under past and future conditions are key elements for the design of flood defense, watercourse demarcation, urban stormwater, road drainage systems. Prediction is difficult and involves high uncertainty, especially for ungaged water¬sheds. Advanced computer capabilities provided by GIS and hydrologic modeling software facilitate computations and allow for the comparison of results by different approaches. Still many empirical relations are included, based on limited field data developed decades ago. Ministry of Infrastructure and Trans¬porta¬tion, Greece, is in the process of updating design guidelines for hydraulic projects, including hydrologic computations. Special Secretariat for Water, Ministry of the Environment and Energy, for the implementation of 2007/60/EU Floods Directive published idf relations for all areas of Greece, based on advanced metho¬dology. Internationally there is a trend towards risk-based design. The basic form of risk-based optimi¬zation is economic optimization aiming at minimi¬zation of the lifetime cost of the project. Climate change impacts is an additional issue that has to be addressed and research for the development of related guidelines is still under way in many countries. Economic and climate change projections also involve high uncertainty.

Session: 21, Room: C, at Fri, 09/06/2019 - 10:00 to 10:15
Oral presentation in Hydrology and water resources management

In this investigation, we use climatic, water-related indicators to evaluate the impact of climate change on the assimilative capacity of the Asopos River, Central Greece. Indicators were developed and organised under the SWICCA climate service (, which aims to develop and showcase a Water Management Information Service for the Copernicus Climate Change Service based, among others, on real case studies and end-users. River flow indicators are the core data for evaluating the assimilative capacity of the Asopos River under different scenarios regarding average flow conditions. Assimilative capacity was evaluated for 6 heavy metals, namely Cr, Cd, Cu, Pb, Ni and Zn. Socioeconomic indicators (GDP and Land Use) were also utilized to incorporate changes of economic activities in the assessment. Climate impact indicators are free of the need for laborious processing. They cannot cover all aspects of local analysis needs but, combined with local information, they are key-data for integrated climate change impact investigations. Results from 226 scenarios of circulation, regional and impact models combinations as well as industrial activity evolution, indicate for the majority of the scenarios, a small impact on the river’s assimilative capacity, associated with climate change, while industrial activity evolution could have a significant effect.

Session: 21, Room: C, at Fri, 09/06/2019 - 09:45 to 10:00
Oral presentation in Hydrology and water resources management

The presence of vegetation in rivers, streams and riparian zones affects significantly the flow field and consequently the resistance, pollutant dispersion, sediment transport and ecological habitat. In this paper, a comparative study is undertaken to investigate the effect of an array of simple rigid or compound semi-flexible elements, resembling submerged small plants, on key features of the flow field. Measurements were taken by means of a 3-D ADV instrument at selected locations within the vegetation array and downstream of it. Vertical profiles of the velocities and turbulent shear stresses were obtained and compared.

Session: 21, Room: C, at Fri, 09/06/2019 - 09:30 to 09:45
Oral presentation in Hydrology and water resources management