Localities visited on Excursions during the Nordic Symposium on Frozen Ground Morphology

Johnsson, G.: Localities visited on Excursions during the Nordic Symposium on Frozen Ground Morphology. Geografisk Tidskrift 82: 99–103. Copenhagen, October 15, 1982.

The localities showing periglacial phenomena of various kinds that were demonstreated on September 7, 8 and 10 during the frozen ground symposia are described in this report with text and illustrations. The objects demonstrated were, i.a., periglacial valleys formed chiefly through gelifluction, an ice-wedge cast with infilling of lime, large ice-wedge casts of the most common type in south Sweden, lateglacial aeolian sand underlain by wind eroded stones and boulders, fossil periglacial ground surfaces with overlying sand with small ice-wedge casts and asymmetrical periglacial valleys.     

Recession curve estimation for storm event separations

An accurate recession curve model is important for separating individual flow events, which is especially difficult over catchments in regions with a maritime climate where frequent rainfall events cause the flows to rise before they reach the baseflow level. The traditional recession curve equations are based on static linear and nonlinear reservoir models. These models work quite well for ground water dominated recession curves, but not so well when the direct runoff is significant in the recession part. In this study, a new modelling methodology is explored based on self-adaptive parameters in the linear and nonlinear reservoir models. It has been found that the adaptive forms performed better than the static ones, especially when a window for the adaptive parameter estimation is properly selected. While the nonlinear adaptive model had better accuracy over the linear one, it could become unstable if its window is too narrow, indicating that more research work is needed to find an useful pattern for the window size. A comparison between the recession curve models and PDM model (a rainfall-runoff model) has shown that they agreed quite well in most winter events, but less so in the summer.     

Thrifty, green or frugal: Reflections on sustainable consumption in a changing economic climate

In the context of a string of economic crises that have affected major world economies between 2007 and 2009, there seems to be a certain amount of overlap between debates around these issues and debates around long term environmental problems such as climate change. One of the interesting points of overlap is a renewed interest in notions of austerity with optimistic commentators offering up hope that a (re)turn to frugality represents a unique opportunity for the pursuit of sustainable consumption. Against this backdrop the analysis sets out an approach to frugality as a social practice and drawing on a qualitative study of persons who identified themselves as attempting to reduce their environmental impacts, it considers the links between frugality and sustainable consumption. Crucially, a distinction is drawn between thrift and frugality in relation to: (1) the scale at which they exercise care and compassion; (2) their relationship to the normative expectations of consumer cultures, and; (3) their consequences in terms of environmental impacts. Taking these distinctions alongside historical analyses of changing consumption patterns, a note of caution is offered that the passage from the economic downturn to sustainable consumption may not be as clear as might be hoped.     

Recession slope curve analysis under human interferences

To study the base flow recession at the watershed scale, the log-scale plot of − dQ/dt ∼ Q proposed by Brutsaert and Nieber [10] has been used to estimate the recession parameters, i.e., the slope and interception of the theoretical recession slope curve. The lower envelope or the best fit in some studies is usually used to determine the recession slope curve for natural watersheds. However, human interferences exist in most watersheds around the world. This paper discusses the impact of human interferences, which include groundwater pumping, water diversion and return flow, on the determination of the recession slope curve and the cloud shape of the data points of − dQ/dt ∼ Q. First, values of − dQ/dt generated for hypothetical watersheds are analyzed. Then real data for three watersheds in Illinois is analyzed to verify the hypothetical analysis. The placement of the recession slope curve depends on the coexistence and relative amount of the evapotranspiration, groundwater pumping or even water diversion if it exists, and the return flow. When the water consumption rate is small, the recession slope curve can even be located at the upper envelope of the cloud of points representing historical data. These results suggest that the use of the lower envelope as a guideline for estimating recession parameters for watersheds subject to human interferences can result in biased estimates.     

A new formula for the sea state and structural parameters influencing the stability of homogeneous reshaping berm breakwaters

The berm recession of a reshaping berm breakwater has a very important role for the stability of this kind of structure. Based on a 2D experimental modeling method in a wave flume, the recession of the berm due to sea state and structural parameters has been studied. Irregular waves with a JONSWAP spectrum were used. A total of 215 tests have been performed to cover the impact of sea state conditions such as wave height, wave period, storm duration and water depth at the toe of the structure, and structural parameters such as berm elevation from still water level, berm width and stone diameter on berm recession. In this paper, first a new dimensionless parameter is introduced to evaluate the combined effect of wave height and wave period on berm recession using results of the experimental work. Then, a formula that includes some sea state and structural parameters is derived using the new dimensionless parameter for estimating the berm recession. A comparison is made between the estimated berm recessions by this new formula and formulae given by other researchers to show the preference of using the new dimensionless parameter. The comparison shows that the recession estimated by the new formula has not only a better correlation with the present experimental data, but also has an improved correlation with other experimental results within the range of parameters tested. Outside the range of parameters tested the Lykke Andersen (2006) formula performed best.     

Information,artifacts, and noise in dQ/dt − Q recession analysis

The plotting of the time rate of change in discharge dQ/dt versus discharge Q has become a widely used tool for analyzing recession data since Brutseart and Nieber [Water Resour Res 13 (1977) 637–643] proposed the method. Typically the time increment Δt over which the recession slope dQ/dt is approximated is held constant. It is shown here this that leads to upper and lower envelopes in graphs of log(−dQ/dt) versus log(Q) that have been observed in previous studies but are artifacts. The use of constant time increments also limits accurate representation of the recession relationship to the portion of the hydrograph for which the chosen time increment is appropriate. Where dQ/dt varies by orders of magnitude during recession, this may exclude much of the hydrograph from analysis. In response, a new method is proposed in which Δt for each observation in time is properly scaled to the observed drop in discharge ΔQ. It is shown, with examples, how the new method can succeed in exposing the underlying relationship between dQ/dt and Q where the standard method fails.     

Evolution of glacial flow and drainage during the ablation season

Proglacial discharge is controlled by the geometry of the glacial drainage network and by meltwater processes. The glacial drainage systems of some alpine glaciers have been characterised using a model based on a proglacial discharge analysis. In this paper, we apply high frequency systemic analysis to data collected from the Baounet Glacier (French Alps) during two successive ablation seasons. Our approach is based on an analysis of the evolution of daily recession curves during the ablation period. The observed data are fitted by a single β-coefficient dependant recession law. Changes in β are compared to variations in the daily discharge amplitude and the time lag between air temperature and proglacial discharge. The changes in the β values do not appear to be related to changes in the time lag and the amplitude of the daily discharge. There were significant variations in the β-coefficient during the two ablation periods studied here even if there was no time lag or the daily discharge amplitude change. High values of β correspond to high drainage velocities; therefore increases in β values can be used as an indicator of the evolution of the glacier’s internal drainage network.     

Karstification in Miocene gypsum: an example from Sivas, Turkey

In this study, karstification developed in the Miocene gypsum which covers a large area around Sivas, Turkey, the relation between regional tectonics and karstification, and hydrogeological features have been investigated. The karstic features in the gypsum have developed conforming to the fault zones and the general strikes of gypsum beds. In the study area, numerous dolines (sinkholes) and ponors (swallow holes) of different sizes are observed. Most of these karstic features are in the different-sized longitudinal depressions (troughs) which conform to the tectonic structures. These karstic features occur NE-SW along bedding planes and about NW-SE and NE-SW along fault zones. At the intersections, high-capacity (yield) karst springs (Göydün and Seyfe springs) are observed. The Göydün and Seyfe springs issue from the karstified gypsum aquifer, with an average discharge of 1.10 m³/s and 0.25 m³/s, respectively. In addition, there are some low-yield (a few l/s) springs in the same drainage area. The surface drainage area of the springs is 64 km², and the precipitation in this area cannot provide the total groundwater discharging from Göydün and Seyfe springs. Water budget calculations indicate that more than 70% of the water discharged by these two springs is provided from the adjacent basins. The Göydün and Seyfe springs are rich in dissolved solids and average electrical conductivities (EC) are about 13?000 μS/cm. The major cations in the waters are Ca and Na; major anions are SO₄ and Cl, and the waters are brackish. Because of these properties, especially in summer and autumn, the springs cause extreme salinization in K?z?l?rmak river.