Correlation between extreme rainfall and insurance claims due to urban flooding – case study Fredrikstad, Norway

During the last decades an increase in extreme rainfall has led to more urban flooding. This study is based on insurance claims of damages caused by heavy rain during 2006-2012 in Fredrikstad, Norway. Data are analysed using Principal Component Analysis. The purpose has been to find characteristics of extreme rainfall and its influence on the extent of urban flooding. The number of claims seems to be peaked in the late summer period. Furthermore, the precipitation depth the week before an extreme rainfall seems to have significantly influence for the pay out from insurers, and thus the changing in runoff factor due to soil wetness is of importance. Compared to 25-year frequency rainfall with 30 min duration, relatively less intensive, but more stable and long-lasting rain seems to lead to more claims. Experiences from previous events may help to determine the level of flood risk when extreme rainfall is forecasted.

Correlation between extreme rainfall and insurance claims due to urban flooding – case study Fredrikstad, Norway

During the last decades an increase in extreme rainfall has led to more urban flooding. This study is based on insurance claims of damages caused by heavy rain during 2006-2012 in Fredrikstad, Norway. Data are analysed using Principal Component Analysis. The purpose has been to find characteristics of extreme rainfall and its influence on the extent of urban flooding. The number of claims seems to be peaked in the late summer period. Furthermore, the precipitation depth the week before an extreme rainfall seems to have significantly influence for the pay out from insurers, and thus the changing in runoff factor due to soil wetness is of importance. Compared to 25-year frequency rainfall with 30 min duration, relatively less intensive, but more stable and long-lasting rain seems to lead to more claims. Experiences from previous events may help to determine the level of flood risk when extreme rainfall is forecasted.

The impact of climate changes on water level of Qinghai Lake in China over the past 50 years

Understanding the variation regularity of lake level and the potential driver factors can provide insights into lake conservation and management. In this study, inter- and inner-annual variations of lake level in Qinghai Lake during the period 1961–2012 were analyzed to determine whether climatic factor or runoff factor were responsible for the variations. The results showed that lake level decreased significantly during the period 1961–2004 at a rate of −7.6 cm/yr, while increasing significantly during the period 2004–2012 at a rate of 14 cm/yr, and all were significant at a p value of <0.01. Lake level was most sensitive to climate and river runoff. Precipitation and river runoff had directly positive effects on lake level, but inverse evaporation and wind speed played a significantly negative role on lake level. The relative contributions of influencing factors in the Southeast Asian monsoon (SEAM) and the westerly circulation periods on annual lake level variations were approximately 49.8% and 27.8%, respectively. The relative contributions of temperature, precipitation, evaporation, and wind speed on lake level variation were approximately 13.8%, 36.3%, 27.1%, and 18.4%, respectively. In general, the annual lake level was primarily influenced by precipitation and evaporation of the SEAM period.

ANALISA TINGKAT BAHAYA EROSI PADA SUB DAS LESTI KABUPATEN MALANG MENGGUNAKAN SISTEM INFORMASI GEOGRAFIS

Ernawan Setyono1& Bangkit Prasetyo21&2Fakultas Teknik Jurusan Teknik Sipil Universitas Muhammadiyah MalangAlamat Korespondensi : Jl. Raya Tlogomas, No.246 Malangemail :[email protected] , Telp 03419591639ABSTRACTSub DAS Lesti is a part of Brantas watershed that located at upstream section and a sub DASpriority. That has 61.491,02 ha of water catchment areas. Hydrological processes that occur in awatershed is closely related to erosion. The alteration of land use and watershed management is oneof the factors causing soil damage, accelerate the erosion rate, and cause erosion. Based on thecondition of that case, this study analyzes about how much the erosion rate, the amount of erosion,and to estimate the level of erosion that will occur.MUSLE method is one of the methods used to determine the magnitude of the erosion rate,that use an approach of runoff factor. Geographic Information Systems (GIS) used for the managementand data processing. Geographic Information Systems is a spatially information technology thatgenerate digital data which can gives the area characteristics, and illustrates the potential of soildamage.The level of erosion hazard on Sub DAS Lesti for weight categories reach 31.421% of thearea, while another erosion rate is Medium 24.146%, Lightweight 22.151%, Very Heavy 16.123%,and Very Light 6.159%.

RAINFALL EROSION INDICES FOR CANADA EAST OF THE ROCKY MOUNTAINS

The use of the universal soil loss equation in Canada to estimate soil loss potential for soil and water conservation planning purposes has been limited by the lack of published rainfall erosion indices and by the arduous procedure generally accepted for determination of these indices. This study was conducted to develop and test relatively simple methods to develop annual rainfall erosion indices and associated seasonal distribution patterns. An approach to the determination of a rainfall-runoff factor to accommodate the effect of winter conditions has also been included. The relatively simple techniques for estimating average annual rainfall erosion indices and seasonal distribution patterns of rainfall erosion have been found to yield comparable values to those determined by more tedious methods. These erosion indices and associated distribution patterns have proven useful for the development of a first approximation of rainfall erosion maps for Canadian locations east of the Rocky Mountains. Key words: Rainfall erosion indices, USLE