Have flood mortality qualitative characteristics changed during the last decades? The case study of Greece

Despite the dramatic increase in recorded flood events in Greece in the last decades, recent findings show that related mortality does not show a corresponding rise. This work develops and studies a database of flood-related fatalities to investigate qualitative changes in flood mortality in the country between 1960 and 2010. Observations show a shift in the circumstances under which fatal incidents occurred and in the demographics of the victims. In particular, indoor fatalities and cases in urban environments gradually decrease in favour of incidents occurring outdoors, in rural settings, mostly using motor vehicles. The number of fatalities per flood event show a decline, indicating that multiple-fatality incidents are gradually disappearing and that advances in protection have an impact on mortality. The increase in the use of vehicles, the improvements in the structural integrity of buildings and the advances in early warning and civil protection practices are found to influence mortality both in qualitative and in quantitative terms.     

Flood monitoring in a semi-arid environment using spatially high resolution radar and optical data

The geographic term "Niger Inland Delta" stands for a vast plain of approximately 40,000 km(2), which is situated in the western Sahel (Republic of Mali). The Inland Delta is affected by yearly inundation through the variable water levels of the Niger-Bani river system. Due to a good availability of (surface) water, the ecosystem at the Niger Inland Delta serves as resting place stop-over for many migrating birds and other wildlife species as well as economic base for farmers and pastoral people. To foster the sustainable usage of its natural resources and to protect this natural heritage, the entire Niger Inland Delta became RAMSAR site in 2004. This paper aims to test to which extent texture analysis can improve the quality of flood monitoring in a semi-arid environment using spatially high resolution ASAR imaging mode data. We found the Gray Level Dependence Method (GLDM) was most suitable proceeding for our data. Several statistical parameters were calculated via co-occurrence matrices and were used to classify the images in different gradation of soil moisture classes. In a second step we used additional information from spatially high resolution optical data (ASTER) to improve the separability of open water areas from moisture/vegetated areas.     

分洪区洪灾保险工作初探

本文从洪水过程的随机特点及防洪工作的实际需要等各个方面出发,阐述了在分洪区实行洪灾保险的必要性,结合国内外已有的实践经验,分析了这一工作得以顺利开展的可能性。并在此基础上,提出了二种洪灾保险费用计算方法,实例计算结果表明,这些方法是基本可行的。     

Managing erosion and water quality in agricultural watersheds by small detention ponds

Terrace-contouring systems with on-site water detention cannot be installed in areas of complex topography, small parceling and multi-blade moldboard plow use. However, field borders at the downslope end may be raised at the deepest part where runoff overtops to create detention ponds, which can be drained by subsurface tile outlets and act similar to terrace-contouring systems. Four of such detention ponds were monitored over 8 years. Monitored effects included the prevention of linear erosion down slope, the sediment trapping from upslope, the enrichment of major nutrients in the trapped and delivered sediments, the amount of runoff retained temporarily, the amount of runoff reduced by infiltration, the decrease in peak runoff rate and the decrease in peak concentrations of agrochemicals due to the mixing of different volumes of water within the detention ponds. The detention ponds had a volume of 30–260 m³ ha⁻¹ and trapped 54–85% of the incoming sediment, which was insignificantly to slightly depleted (5–25%) in organic carbon, phosphorus, nitrogen and clay as compared to the eroding topsoil, while the delivered sediment was strongly enriched (+70–270%) but part of this enrichment already resulted from the enrichment of soil loss. The detention ponds temporarily stored 200–500 m³ of runoff. A failure was never experienced. Due to the siltation of the pond bottom, the short filled time (1–5 days) and the small water covered area, infiltration and evaporation reduced runoff by less than 10% for large events. Peak runoff during heavy rains was lowered by a factor of three. Peak concentrations of agrochemicals (Terbutylazin) were lowered by a factor of two. The detention ponds created by raising the downslope field borders at the pour point efficiently reduced adverse erosion effects downslope the eroding site. They are cheap and can easily be created with on-farm machinery. Their efficiency is improved where they are combined with an on-site erosion control like mulch tillage because sediment and runoff input are reduced. Ponds had to be dredged only after the first year when on-site erosion control was not fully effective.     

Mapping Outlets of Iowa Flood Center and National Water Center River Networks for Hydrologic Model Comparison

River networks based on Digital Elevation Model (DEM) data differ depending on the DEM resolution, accuracy, and algorithms used for network extraction. As spatial scale increases, the differences diminish. This study explores methods that identify the scale where networks obtained by different methods agree within some margin of error. The problem is relevant for comparing hydrologic models built around the two networks. An example is the need to compare streamflow prediction from the Hillslope Link Model (HLM) operated by the Iowa Flood Center (IFC) and the National Water Model (NWM) operated by the National Water Center of the National Oceanic and Atmospheric Administration. The HLM uses landscape decomposition into hillslopes and channel links while the NWM uses the NHDPlus dataset as its basic spatial support. While the HLM resolves the scale of the NHDPlus, the outlets of the latter do not necessarily correspond to the nodes of the HLM model. The authors evaluated two methods to map the outlets of NHDPlus to outlets on the IFC network. The methods compare the upstream areas of the channels and their spatial location. Both methods displayed similar performance and identified matches for about 80% of the outlets with a tolerance of 10% in errors in the upstream area. As the aggregation scale increases, the number of matches also increases. At the scale of 100 km², 90% of the outlets have matches with tolerance of 5%. The authors recommend this scale for comparing the HLM and NWM streamflow predictions.     

从湖泊水域环境异变论洞庭湖区洪涝灾害

分析了洞庭湖泥沙淤积，人类活动的合成作用而导致湖泊水域环境界变及其对洪涝灾害的负效应。并从改善湖泊水域环境的角度上，提出了节制进口，疏浚河湖，稳定湖面和扩大出口等有效治理途径，以尽快提高洞庭湖区的防洪排涝能力。     

Improving flood warnings in Europe: a research and policy agenda

Abstract

Warnings and emergency planning for flooding are based on the reality that no matter how thorough our investigations and flood prevention efforts through engineered structural works or land use management, some risk will always remain. This paper examines recent experience with flood warnings in the UK and continental Europe. It combines this experience with an overview of the relevant literature to identify lessons for incorporation into policy, and problem areas which would most obviously benefit from additional research. Throughout, the emphasis is on the non-engineering aspects of warning systems. Results indicate that much is being achieved in terms of the detail of warning design, but the broader issues seem to be largely ignored by both the research literature and practice. First among these broader issues is the failure, by those charged with warning system development and operation, to conceptualise the warning task as one based explicitly on the needs of those at risk. Making this happen will require the development of processes to build the necessary culture of cooperation and learning among the many organisations involved.