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[en] Continuous recording of different geophysical parameters incorporated at a single location as a unified effort for earthquake precursory through geodynamical changes initiated for the first time in the Garhwal Himalaya, India. A 68 m deep borehole, penetrating into the water table is operated for continuous radon monitoring along with meteorological/geohydrological observations at two points, one at 10 m (in the air column) and the second one at 50 m (within water column) depths from surface. Preliminary studies reveal diagnostic short duration anomalies in radon concentration recorded few days before the occurrence of a nearby moderate M4.9 earthquake at Kharsali on the 23rd of July, 2007. For nearly half of the year, radon emanation at 10 m depth in the closed air column showed definite pattern of daily variations that may be due to the influence of tidal forces, meteorological and other geodynamical phenomena. This pattern is totally missing during June and July, 2007 when few anomalies for small durations were observed out of which two are unique. These two anomalies exceed 2σ (standard deviation) from average radon concentration in both positive and negative sides. However, its emanation at 50 m depth (water radon) is almost constant throughout the year 2007 except some disturbances observed to the ending of June and during July. These abnormalities in radon emanation and other parameters in the borehole may be considered precursory to the M4.9 Kharsali earthquake of July 23, 2007 having an epicenter distance of 60 km. The empirical relation used for amount of radon anomaly with the epicenter distance predicts an earthquake of M4.6 and M4.7 with the observed anomaly at 10 m and 50 m observation points respectively after taking a 60 km epicenter distance.
[en] The development of vulnerability maps is considered to be the first step in promoting awareness, development of protection strategies and sustainable use of karst aquifers. Nevertheless, high subjectivity of current methodologies for groundwater vulnerability assessment leads to contradictory results when different models are applied over the same area. This makes it difficult for water institutions and decision makers to determine a method to be used on a specific karst area. Four European methods (EPIK, PI, COP and PaPRIKa) were applied for the Yucatan karst to estimate groundwater vulnerability and determine if any of these European methods display vulnerability outcomes in correspondence with regional characteristics such as sinkhole alignments and the shallow water table. Agreement between methodologies was evaluated according to the spatial match on vulnerability rates displayed by final maps; intrinsic features influencing such match and divergent factors were highlighted. Similar vulnerabilities, with more than 52% in average of spatial agreement, were found between COP, PI and EPIK maps. A considerable average up to 33% of match in moderate vulnerability between these three methods was analysed. However, despite the methods displaying similarities regarding moderate vulnerability, these methodologies show no congruence with regional characteristics. A result of a moderate vulnerability on Yucatan coastal and central areas, where the unsaturated zone reaches just a couple of metres, is not an accurate outcome for the shallow water table. Adaptations of these methods or a new integrated methodology would be necessary to estimate groundwater vulnerability in the Yucatan karst.
[en] Tinderet natural forest is part of the extensive Mau complex and forms an important hydrological system for lake Victoria. Information on on economic values of most forests in Kenya are not available or scanty. This paper aims at estimating the total economic value of Tinderet forest. Surveys were conducted on 109 households sampled from three villages within five kilometers of the forest. Further information/data was to determine direct use values. Other indirect use values (carbon sequestration and soil conservation) were were estimated by use of secondary data where the data not available, benefit transfer method was adopted. It was established that, the annual direct use of value to forest adjacent households is about Ksh. 33 million. The indirect use value is estimated at Ksh. 270 million and this value accrues to global community and not restricted to Kenya. The opportunity cost of conserving the Tinderet natural forest is estimated at Ksh. 210 million and only about Ksh. 33 million per year accrue as direct use values to the whole community. The current benefit from forest is inadequate to offset the community cost of of leaving the forest in it's present state. Based on this analysis, the government and the local communities are subsidizing the retention of the forest and this subsidy is currently estimated at at Ksh. 67 million through lost opportunity in settlement and income. In order to promote positive attitudes of the community adjustment to the forest on sustainable use of the forest, consumptive use of the forest should be encouraged
[en] Geostatistical analysis of hydraulic head data is useful in producing unbiased contour plots of head estimates and relative errors. However, at most sites being characterized, monitoring wells are generally present at different densities, with clusters of wells in some areas and few wells elsewhere. The problem that arises when kriging data at different densities is in achieving adequate resolution of the grid while maintaining computational efficiency and working within software limitations. For the site considered, 113 data points were available over a 14-mi2 study area, including 57 monitoring wells within an area of concern of 1.5 mi2. Variogram analyses of the data indicate a linear model with a negligible nugget effect. The geostatistical package used in the study allows a maximum grid of 100 by 100 cells. Two-dimensional kriging was performed for the entire study area with a 500-ft grid spacing, while the smaller zone was modeled separately with a 100-ft spacing. In this manner, grid cells for the dense area and the sparse area remained small relative to the well separation distances, and the maximum dimensions of the program were not exceeded. The spatial head results for the detailed zone were then nested into the regional output by use of a graphical, object-oriented database that performed the contouring of the geostatistical output. This study benefitted from the two-scale approach and from very fine geostatistical grid spacings relative to typical data separation distances. The combining of the sparse, regional results with those from the finer-resolution area of concern yielded contours that honored the actual data at every measurement location. The method applied in this study can also be used to generate reproducible, unbiased representations of other types of spatial data
[en] The purpose of this model report is to document the unsaturated zone (UZ) radionuclide transport model, which evaluates, by means of three-dimensional numerical models, the transport of radioactive solutes and colloids in the UZ, under ambient conditions, from the repository horizon to the water table at Yucca Mountain, Nevada
[en] Electrical impedance tomography (EIT) was used to image the plume resulting from a release of 378 liters (100 gallons) of gasoline into a sandy acquifer. Images were made in 5 planes before and 5 times during the release, to generate a detailed picture of the spatial as well as the temporal development of the plume as it spread at the water table. Information of the electrical impedance (both in phase and out of phase voltages) was used or several different frequencies to produce images. We observed little dispersion in the images either before or after the gasoline entered the acquifer. Likewise, despite some laboratory measurements of impedances, there was no evidence of a change in the reactance in the soil because of the gasoline
[en] While making investigations of glacial relic bryophytes in Belianske luky mire, we recorded seasonal change in cover of selected bryophytes. It was decided to perform repeated monitoring between 2008-2010, in three replicates each year. In particular, the main observation was the decreasing cover of Campylium stellatum and Drepanocladus cossonii in the course of the year. In order to explain the seasonal change, we have sampled physico-chemical features of the examined sites: pH, redox potential (ORP), conductivity, total dissolved solids (TDS), salinity, dissolved oxygen, chemical oxygen demand (COD), CaCO/sub 3/, NO/sub 3/, SO/sub 4/, NH/sub 4/ and Cl. Results show that within investigated sites the distribution of Campylium stellatum and Drepanocladus cossonii was mostly limited by decreasing concentration of NH/sub 4/ and increasing concentration of NO/sub 3/ in the course of the year. The phylogenetic diversity of the bacterial community in the water sample from Belianske luky meadows was investigated using a PCR of the 16SrRNA gene. After screening by Terminal Restriction Fragment Length Polymorphism (T-RFLP) method, we made in silico analysis, confirming the presence of nitrifying bacteria.The seasonal variation in bryophytes cover is induced by the synergic influence of decomposition of organic substances in soils, by nitrifying bacteria activity and by unstable the water table. (author)
[en] A process-based model (Forest-DNDC) was applied to describe the possible impacts of climate change on carbon dioxide (CO2) fluxes from a peat bog in European Russia. In the first step, Forest-DNDC was tested against CO2 fluxes measured by the eddy covariance method on an oligotrophic bog in a representative region of the southern taiga (56 deg. N 33 deg. E). The results of model validations show that Forest-DNDC is capable of quantifying the CO2 fluxes from the bog ecosystem. In the second step, the validated model was used to estimate how the expected future changes of the air temperature and water table depth could affect the C dynamics in the bogs. It was shown that a decrease in the water table and an increase in temperature influence significantly the CO2 exchange between our bog ecosystem and the atmosphere. Under elevated temperature and deepened water table the bog ecosystems could become a significant source of atmospheric CO2.
[en] Estimation of near-surface models from refraction data conventionally involves picking of arrival times for the direct and head waves. However, it is often difficult to pick the direct wave automatically on shot records if the direct-wave arrival is not a first arrival. The linear moveout velocity analysis method is proposed here to overcome this difficulty. The method is applied to help estimate the depth to the watertable at three locations in the eastern province of Saudi Arabia. The data consist of three shot records acquired in coastal sabkhas with a very shallow watertable, making it possible to check the analysis results. Conventional automatic picking algorithms failed to pick the direct arrivals in these records because the direct arrivals always come after other arrivals. The proposed method is used to estimate the direct-arrival velocities in these records and the depths to the watertable are estimated. Comparison of estimated and true water depths shows that the error was within 8%. In addition, the direct-wave velocities estimated by the proposed method showed almost perfect agreement with results from a previous study in two of the tested areas in which manual picking of the direct-wave arrivals was used