| publications-31 |
|
2010 |
Saner, D |
Is it Only CO2 that Matters? A Life Cycle Perspective on Shallow Geothermal Systems |
|
10.1016/j.rser.2010.04.002 |
Data Management & Analytics |
Uncategorized |
|
No abstract available |
220620 |
|
|
|
| publications-32 |
|
2010 |
Bayer, P |
Optimization of high-reliability based hydrological design problems by robust automatic sampling of |
|
10.1029/2009wr008081 |
Simulation & Modeling |
Natural Water Bodies |
|
This study demonstrates the high efficiency of the soâcalled stackâordering technique for optimizing a groundwater management problem under uncertain conditions. The uncertainty is expressed by multiple equally probable model representations, such as realizations of hydraulic conductivity. During optimization of a wellâlayout problem for contaminant control, a ranking mechanism is applied that extracts those realizations that appear most critical for the optimization problem. It is shown that this procedure works well for evolutionary optimization algorithms, which are to some extent robust against noisy objective functions. More precisely, differential evolution (DE) and the Covariance Matrix Adaptation Evolution Strategy (CMAâES) are applied. Stack ordering is comprehensively investigated for a plume management problem at a hypothetical template site based on parameter values measured at and on a geostatistical model developed for the Lauswiesen study site near TĂŒbingen, Germany. The straightforward procedure yields computational savings above 90% in comparison to always evaluating the full set of realizations. This is confirmed by cross testing with four additional validation cases. The results show that both evolutionary algorithms obtain highly reliable nearâoptimal solutions. DE appears to be the better choice for cases with significant noise caused by small stack sizes. On the other hand, there seems to be a problemâspecific threshold for the evaluation stack size above which the CMAâES achieves solutions with both better fitness and higher reliability. |
220620 |
|
|
|
| publications-33 |
|
2010 |
Hecht-Méndez, J |
Evaluating MT3DMS for heat transport simulation of closed geothermal systems |
|
10.1111/j.1745-6584.2010.00678.x |
Cost-Benefit Analysis |
River Basins |
|
Owing to the mathematical similarities between heat and mass transport, the multiâspecies transport model MT3DMS should be able to simulate heat transport if the effects of buoyancy and changes in viscosity are small. Although in several studies solute models have been successfully applied to simulate heat transport, these studies failed to provide any rigorous test of this approach. In the current study, we carefully evaluate simulations of a single borehole ground source heat pump (GSHP) system in three scenarios: a pure conduction situation, an intermediate case, and a convectionâdominated case. Two evaluation approaches are employed: first, MT3DMS heat transport results are compared with analytical solutions. Second, simulations by MT3DMS, which is finite difference, are compared with those by the finite element code FEFLOW and the finite difference code SEAWAT. Both FEFLOW and SEAWAT are designed to simulate heat flow. For each comparison, the computed results are examined based on residual errors. MT3DMS and the analytical solutions compare satisfactorily. MT3DMS and SEAWAT results show very good agreement for all cases. MT3DMS and FEFLOW twoâdimensional (2D) and threeâdimensional (3D) results show good to very good agreement, except that in 3D there is somewhat deteriorated agreement close to the heat source where the difference in numerical methods is thought to influence the solution. The results suggest that MT3DMS can be successfully applied to simulate GSHP systems, and likely other systems with similar temperature ranges and gradients in saturated porous media. |
220620 |
|
|
|
| publications-34 |
|
|
Bayer, P. |
On the potential of Life Cycle Assessment in Water Resources Management: Focus on Groundwater |
|
|
Hydrological modeling |
River Basins |
|
No abstract available |
220620 |
|
|
|
| publications-35 |
|
|
Bayer, P |
Indirect water management: How we all can participate. |
|
|
Uncategorized |
Natural Water Bodies |
|
No abstract available |
220620 |
|
|
|
| publications-36 |
|
|
Kollet, S |
Influence of the Sensible Heat of Rain, Subsurface Heat Convection and the Lower Temperature Boundar |
|
|
Uncategorized |
Precipitation & Ecological Systems |
|
No abstract available |
220620 |
|
|
|
| publications-37 |
|
2009 |
Maier, U |
Calibration of hydraulic parameters for large-scale vertical flow constructed wetlands |
|
10.1016/j.jhydrol.2009.02.032 |
Uncategorized |
Precipitation & Ecological Systems |
|
No abstract available |
220620 |
|
|
|
| publications-38 |
PEER REVIEWED ARTICLE |
2012 |
Brucet, S. |
Effects of temperature, salinity and fish in structuring the macroinvertebrate community in shallow lakes: implications for effects of climate change |
|
10.1371/journal.pone.0030877 |
Uncategorized |
Natural Water Bodies |
|
No abstract available |
226273 |
|
|
|
| publications-39 |
PEER REVIEWED ARTICLE |
2010 |
Brucet, S. |
Factors influencing zooplankton size structure at contrasting temperatures in coastal shallow lakes: implications for effects of climate change. |
|
10.4319/lo.2010.55.4.1697 |
Cost-Benefit Analysis |
River Basins |
|
We assessed the importance of temperature, salinity, and predation for the size structure of zooplankton and provided insight into the future ecological structure and function of shallow lakes in a warmer climate. Artificial plants were introduced in eight comparable coastal shallow brackish lakes located at two contrasting temperatures: coldâtemperate and Mediterranean climate region. Zooplankton, fish, and macroinvertebrates were sampled within the plants and at openâwater habitats. The fish communities of these brackish lakes were characterized by smallâsized individuals, highly associated with submerged plants. Overall, higher densities of small planktivorous fish were recorded in the Mediterranean compared to the coldâtemperate region, likely reflecting temperatureârelated differences as have been observed in freshwater lakes. Our results suggest that fish predation is the major control of zooplankton size structure in brackish lakes, since fish density was related to a decrease in mean body size and density of zooplankton and this was reflected in a unimodal shaped biomassâsize spectrum with dominance of small sizes and low size diversity. Salinity might play a more indirect role by shaping zooplankton communities toward more saltâtolerant species. In a globalâwarming perspective, these results suggest that changes in the trophic structure of shallow lakes in temperate regions might be expected as a result of the warmer temperatures and the potentially associated increases in salinity. The decrease in the density of largeâbodied zooplankton might reduce the grazing on phytoplankton and thus the chances of maintaining the clear water state in these ecosystems. |
226273 |
|
|
|
| publications-40 |
PEER REVIEWED ARTICLE |
2010 |
Vaquer-Sunyer, R. |
Sulfide exposure accelerates hypoxia-driven mortality |
|
10.4319/lo.2010.55.3.1075 |
Uncategorized |
River Basins |
|
The effect of the presence of sulfide on the survival of benthic organisms under hypoxia was tested using a metaâanalysis of published experimental results evaluating the effects of the presence of hydrogen sulfide on the median survival time of benthic macrofauna under hypoxia. The metaâanalysis confirmed that survival times under hypoxia are reduced by an average of 30% in marine benthic communities exposed to hydrogen sulfide. The effect of sulfide on survival was higher for egg forms than for juvenile or adult stages. The aggravation of the negative effects of spreading hypoxia in the presence of sulfide suggests that the threats derived from hypoxia to marine biodiversity are greater than anticipated on the basis of the direct effects of low oxygen concentration alone. |
226273 |
|
|
|