APPLICATION OF THE TRRL FLOOD ESTIMATION MODEL IN HYDROLOGICAL FORECASTING FOR CATCHMENTS WITH LIMITED DATA A CASE STUDY

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Regional hydrological thresholds for landslides and floods in the Tiber River Basin (central Italy)

 The definition of landslide warning thresholds, based on the analysis of hydrological data, is proposed. In the Tiber River Basin of central Italy historical information on landslides and floods, for the period 1918–1990, was available from a nationwide bibliographical and archive inventory on geohydrological catastrophes. Hydrological data were obtained from mean daily discharge records at various gauging stations within the basin. Several hundred hydrological events, broadly defined as a series of consecutive days having mean daily discharge exceeding a predefined value, were identified. Hydrological parameters obtained from the discharge records were used to rank the events according to their probability to trigger mass movements or inundations and to define regional thresholds for the occurrence of landslides and floods. The proposed approach, not lacking limitations, has conceptual and operational advantages, among which is the possibility of using historical information on geohydrological catastrophes. Received: 20 November 1996 · Accepted: 25 June 1997     

论油气勘探开发中的水文地质,工程地质方法技术

油气勘探开发涉及水文地质,工程地质许多领域及其方法技术,油气水烃类,矿化度等有机,无机地球化学信息是判别油气成藏与油气运移的重要依据,通过对此类地化参数的检测可有效地指导油气勘探,如塔中,松南。油田水文地质直接关系到油田开发方案的合理设计与顺利实施－对油田水文地质条件前期分析,开采中水文地质参数的跟踪监测,选择合适的注水方式,时机及注水量,是油田稳产增产的关键;钻井,试采工程技术受不同工区（地表,     

五大连池火山区水文地球化学背景

五大连池火山区水文地球化学背景孙如波杜建国（黑龙江省五大连池地震火山监测站,五大连池１６４１５５）（国家地震局分析中心,北京１０００３６）关键词地下水地球化学五大连池五大连池火山群是我国较年轻的火山群之一,火山喷发时间为２０７６Ｍａ至公元１７２１...     

Palmer's Drought Indices Revisited

Palmer's Hydrological and Meteorological Drought Severity Indices are reviewed along with a number of recent modifications that help reduce ambiguity from decision concerning the beginning and ending of drought conditions. Based on data from Regina, Saskatchewan, it is shown that the Meteorological Index, due to its greater sensitivity, responds at least one month faster to changing moisture conditions than the Hydrological Index and is consequently recommended for forward planning in water resource management and agriculture. Assumptions regarding differences in available water capacity of up to 100 mm resulted in maximum absolute differences of up to 0.30 in the Hydrological Index and 0.36 in the Meteorological Index, both evaluated as statistically non-significant.     

RQD研究的几个理论问题

岩石质量指标ＲＱＤ是岩体工程分类和稳定性评价中最常用的定量描述参数。３０多年来,ＲＱＤ的概念和理论研究有了重大进展。本文对源于工程应用的几个ＲＱＤ理论问题进行了评述,同时提出了一些新的研究思路。     

An Analysis of Spatial and Temporal Dimension of Drought Vulnerability in Turkey Using the Standardized Precipitation Index

Drought has become a recurrent phenomenon in Turkey in the last few decades. Significant drought conditions were observed during years of late 1980s and the trend continued in the late 1990s. The countrys agricultural sector and water resources have been under severe constraints from the recurrent droughts. In this study, spatial and temporal dimensions of meteorological droughts in Turkey have been investigated from vulnerability concept. The Standardized Precipitation Index (SPI) method was used to detail geographical variations in the drought vulnerability based on frequency and severity of drought events at multiple time steps. Critical (threshold) rainfall values were derived for each station at multiple-time steps in varying drought categories to determine least amount of rainfall required to avoid from drought initiation. The study found that drought vulnerability portrays a very diverse but consistent picture with varying time steps. At regional scale, south-eastern and eastern Anatolia are characterized with moderate droughts at shorter time steps, while the occurrence of severe droughts at shorter time steps is observed at non-coastal parts of the country. A similar picture was observed with very severe droughts. The critical (threshold) values exhibited rising numbers during the growing season at 3-month step in the South-eastern Anatolia, which might have significant consequences considering presence of large irrigation projects under-development in the region. In general, rainfall amounts required for non-drought conditions decrease from the coastal parts toward the interiors with increasing time steps.     

Water quality modeling of the Cahaba River,Alabama

The Cahaba River, a sixth-order stream, tributary to the Mobile-Alabama River, is one of the few free-flowing rivers in Alabama. The Cahaba River lies in north-central Alabama and its watershed includes a variety of land uses from forested and agricultural to urban. Water quantity and quality modeling of the Cahaba River using several modules of the hydrologic simulation program FORTRAN (HSPF) and the nonpoint source model (NPSM) using the GIS-based BASINS package showed good agreement with measured flow data for low- and high-flow years but poor agreement with total nitrogen concentrations in the water column. Disparities between modeling and measured water quality data are attributed to the limited point source data available for nitrogen inputs to the stream and the lack of nitrogen-transformation process modeling with the NPSM. Future simulations should include use of models with detailed nitrogen transformation modules.     

Travel-times and Attenuation Relations for Regional Phases in the Barents Sea Region

A database containing 45 events in the Barents Sea region has been compiled and analyzed with the aim of evaluating crustal models, travel-times and attenuation relations in the context of performing regional detection threshold monitoring of this region. The 45 events are mostly located around the circumference of the study area due to the virtually aseismic nature of the Barents Sea itself. Regional P _n and S _n phases were observable for most events in the database, while P _g and L _g phases were only observable for events with raypaths that do not cross the tectonic structures in the Barents Sea. This corroborates a number of previous observations of L _g -wave blockage within the Barents Sea. Three existing velocity models were evaluated, with a model having slightly lower S velocities than earlier assumed in the upper mantle giving the overall best fit to the observed arrivals. In order to estimate magnitudes, short-term average (STA) and spectral amplitude values were calculated in several frequency bands for all phase arrivals in the database. There were no significant differences between spectral and STA amplitudes, so the latter were used as this parameter is more efficient to calculate in real-time processing. An inversion was performed in order to determine an attenuation relation specific for this region. The resulting magnitudes based on P _n , P _g , S _n and L _g phases gave an internally consistent, reasonably stable set of values, which can be calibrated towards any existing global or regional scale.     

Towards Establishing Climatic Thresholds for Slope Instability: Use of a Physically-based Combined Soil Hydrology-slope Stability Model

— Shallow landslides are often linked to high magnitude rainstorms. Research has attempted to establish threshold rainfall totals that trigger shallow landslides, based mainly on field evidence. Complications arise because not all regolith has the same hydrological behaviour, and research frequently fails to take this into account. This paper uses a combination of field and modelling approaches to explore the triggering rainfall thresholds for shallow failures in deforested hill country of New Zealand. It emphasises the role of variations in regolith hydrology, focussing on unsaturated and saturated zone responses. By using a modelling approach, detailed variations in pore pressure (positive and negative) responses are investigated, developing ideas initially derived from field evidence. This paper defines and develops earlier research that establishes values for maximum and minimum probability thresholds for shallow landslides, and provides a more generalised model that can be applied more widely. Hydrological mechanisms for shallow landslides are investigated in greater detail than previously possible using a Combined Hydrology And Stability Model (CHASM).Received: 20 August 2001