The search for landfill sites – requirements and implementation in Lower Saxony, Germany

 In Germany, landfilling and incineration are the main techniques for the disposal of waste. However, due to humid climatic conditions, leakage of contaminated water from landfills into the subsurface poses a considerable threat to the environment. Therefore, the German states require high safety standards for the construction of a landfill. Emphasis is put on the presence of natural geological barrier rocks. Clay and silts, claystones and siltstones are best suited to meet the requirements defined in legal waste regulations. With regard to retardation capacity, thickness is considered of higher importance than hydraulic permeability. Suitable areas have to be reduced by legally excluded areas. A site search program in Lower Saxony revealed that only 1% of the total state area falls into the best suitability category. Geoscientific investigations on the remaining suitable areas have to become more detailed in the search progress. Geographical information systems (GIS) are the most adequate tools to work on all involved data and to present and outline the results. GIS make the results transparent and understandable to the public. These investigations are a necessary part of the environmental impact assessment which is obligatory for a landfill site's construction. Criteria catalogues take all important aspects of the search process into consideration and help to find the most suitable site. Received: 17 March 1997 · Accepted: 6 June 1997     

Application of arma models to estimate earthquake ground motion and structural response

This paper deals with the use of ARMA models in earthquake engineering. Tools and methods applied to strong ground motion are discussed emphasizing simulation of probabilistic earthquake response spectra. The ARMA models are applied to Icelandic earthquake data and a tentative model for Icelandic earthquakes is presented. This model, which is derived using 54 accelerograms, is based on a low-order, time-invariant ARMA process excited by Gaussian white noise and amplitude modulated using a simple envelope function to account for the non-stationary characteristics. This simple model gives a reasonable fit to the observed ground motion. Further, this model produces accurate earthquake response spectra, which, combined with accompanying attenuation and duration formulae, might be useful in earthquake hazard and risk assessment.     

Quantifying changes of effective springshed area and net recharge through recession analysis of spring flow

The average flow of Silver Springs, one of the largest magnitude springs in Central Florida, declined 32% from 2000 to 2012. The average groundwater head in the springshed declined 0.14 m, and the spring pool altitude increased 0.24 m during the same period. This paper presents a novel explanation of the spring flow recession curve for Silver Springs using the Torricelli model, which uses the groundwater head at a sentinel well, the spring pool altitude and the net recharge to groundwater. The effective springshed area and net recharge (defined as recharge minus groundwater pumping and evapotranspiration) were estimated based on the observed recession slopes for spring flow, groundwater head and spring pool altitude. The results indicate that the effective springshed area continuously declined since 1989 and the net recharge declined since the 1970s with a significant drop in 2002. Subsequent to 2002, the net recharge increased modestly but not to the levels prior to the 1990s. The reduction in net recharge was caused by changes in hydroclimatic conditions including precipitation and air temperature, along with groundwater withdrawals, which contributed to the declined spring flow. Copyright © 2016 John Wiley & Sons, Ltd.     

A geophysical survey of the De Gerlache Seamounts: preliminary results

 The De Gerlache Seamounts actually consist of two medium-sized guyots, with summits at depths of 350–600 m. Acoustic profiler data show no significant sediment on these guyots. Alkaline basalts dredged from the summit of the eastern guyot yield K/Ar ages between 20.1±1.0 and 23.2±1.2 Ma. Basement ridges and sediment-filled troughs between the guyots are associated with the prominent gravity anomaly extending north from the Antarctic margin. This structure possibly played a role in the guyot formation, however, the question of how the De Gerlache Seamounts are related to this gravity anomaly remains uncertain. Received: 13 February 1997 / Revision received: 30 September 1997     

Fuzzy set approach to assessing similarity of categorical maps

For the evaluation of results from remote sensing and high-resolution spatial models it is often necessary to assess the similarity of sets of maps. This paper describes a method to compare raster maps of categorical data. The method applies fuzzy set theory and involves both fuzziness of location and fuzziness of category. The fuzzy comparison yields a map, which specifies for each cell the degree of similarity on a scale of 0 to 1. Besides this spatial assessment of similarity also an overall value for similarity is derived. This statistic corrects the cell-average similarity value for the expected similarity. It can be considered the fuzzy equivalent of the Kappa statistic and is therefore called K_Fuzzy. A hypothetical case demonstrates how the comparison method distinguishes minor changes and fluctuations within patterns from major changes. Finally, a practical case illustrates how the method can be useful in a validation process.     

Analysis of multibeam-Hydrosweep echo peaks for seabed characterisation

Echo-peak data of outer and normal incidence beams from five different Southern Ocean bottom topographic regions have been analysed. The Rice and Extremal probability density function (PDF) statistical approaches reveal that the seabed roughness is, in general, Gaussian in nature except in the case of the Kainan Maru seamount summit (area D). The outer beams of the Enderby abyssal plain (area C) echo-peak PDF statistics reveal the highest possible large-scale feature dominance. Interestingly, Extremal PDF fit parameters (!) from the Agulhas Basin (area A) show a less dominant large-scale roughness than in the case of area C. Large-scale feature dominance up to 15° beam angle is observed in the case of mixed roughness seabeds such as area B (southwest Indian ridge) and area E (Meteor Rise). No increase in the 30°-beam Extremal PDF parameters is observed in these areas. Maximum microtopographic roughness is documented in area D on the summit of Kainan Maru seamount. The estimated fit parameters using Extremal statistics of outer-beam peak data provide a better understanding of the scattering process. Previously determined power law and volume roughness parameters using composite roughness theory are given for the five different areas. These support the results obtained using Rice and Extremal PDFs. The existence of higher volume roughness parameters and power law parameters for medium-scale roughness, along with dominant microtopographic features, are evident from the results of this study.     

Transboundary environmental problems: the case of the burning of coal in Poland for heating and electricity purposes

Transboundary environmental problems have increased in prevalence over recent years in Eastern Europe where the scope and extent of the problems, and hence possibility of impacts outside of national borders, have been considerably greater than in western nations. This paper examines an example of a transboundary environmental risk problem, namely that of coal burning in Poland. The case study focuses on determining both Polish policy makers’ and the public’s views regarding the perceived importance of local vis-a-vis transboundary environmental concerns.     

Coupled garnet Lu–Hf and monazite U–Pb geochronology constrain early convergent margin dynamics in the Ross orogen,Antarctica

The Ross orogen of Antarctica is an extensive (>3000 km‐long) belt of deformed and metamorphosed sedimentary rocks and granitoid batholiths, which formed during convergence and subduction of palaeo‐Pacific lithosphere beneath East Gondwana in the Neoproterozoic–early Palaeozoic. Despite its prominent role in Gondwanan convergent tectonics, and a well‐established magmatic record, relatively little is known about the metamorphic rocks in the Ross orogen. A combination of garnet Lu–Hf and monazite U–Pb (measured by laser‐ablation split‐stream ICP‐MS) geochronology reveals a protracted metamorphic history of metapelites and garnet amphibolites from a major segment of the orogen. Additionally, direct dating of a common rock‐forming mineral (garnet) and accessory mineral (monazite) allows us to test assumptions that are commonly used when linking accessory mineral geochronology to rock‐forming mineral reactions. Petrography, mineral zoning, thermobarometry and pseudosection modelling reveal a Barrovian‐style prograde path, reaching temperatures of ~610–680 °C. Despite near‐complete diffusional resetting of garnet major element zoning, the garnet retains strong rare earth element zoning and preserves Lu–Hf dates that range from c. 616–572 Ma. Conversely, monazite in the rocks was extensively recrystallized, with concordant dates that span from c. 610–500 Ma, and retain only vestigial cores. Monazite cores yield dates that overlap with the garnet Lu–Hf dates and typically have low‐Y and heavy rare earth element (HREE) concentrations, corroborating interpretations of low‐Y and low‐HREE monazite domains as records of synchronous garnet growth. However, ratios of REE concentrations in garnet and monazite do not consistently match previously reported partition coefficients for the REE between these two minerals. High‐Y monazite inclusions within pristine, crack‐free garnet yield U–Pb dates significantly younger than the Lu–Hf dates for the same samples, indicating recrystallization of monazite within garnet. The recrystallization of high‐Y and high‐HREE monazite domains over >50 Ma likely records either punctuated thermal pulses or prolonged residence at relatively high temperatures (up to ~610–680 °C) driving monazite recrystallization. One c. 616 Ma garnet Lu–Hf date and several c. 610–600 Ma monazite U–Pb dates are tentatively interpreted as records of the onset of tectonism metamorphism in the Ross orogeny, with a more robust constraint from the other Lu–Hf dates (c. 588–572 Ma) and numerous c. 590–570 Ma monazite U–Pb dates. The data are consistent with a tectonic model that involves shortening and thickening prior to widespread magmatism in the vicinity of the study area. The early tectonic history of the Ross orogen, recorded in metamorphic rocks, was broadly synchronous with Gondwana‐wide collisional Pan‐African orogenies.     

Impacts of changing climate on the hydrology and hydropower production of the Tagus River basin

The Tagus River basin is an ultimately important water source for hydropower production, urban and agricultural water supply in Spain and Portugal. Growing electricity and water supply demands, over‐regulation of the river and construction of new dams, as well as large inter‐basin and intra‐basin water transfers aggravated by strong natural variability of climate in the catchment, have already imposed significant pressures on the river. The substantial reduction of discharge is observed already now, and projected climatic change is expected to alter the water budget of the catchment further.In this study, we address the effects of projected climate change on the water resources availability in the Tagus River basin and influence of potential changes on hydropower generation of the three important reservoirs in the basin. The catchment‐scale, process‐based eco‐hydrological model soil and water integrated model was set up, calibrated and validated for the entire Tagus River basin, taking into account 15 large reservoirs in the catchment. The future climate projections were selected from those generated within the Inter‐Sectoral Impact Model Intercomparison Project. They include five bias‐corrected climatic datasets for the region, obtained from global circulation model runs under two emissions scenario – moderate and extreme ones – and covered the whole century. The results show a strong agreement among model runs in projecting substantial decrease of discharge of the Tagus River discharge and, consequently, a strong decrease in hydropower production under both future climate scenarios. Copyright © 2016 John Wiley & Sons, Ltd.