Adaptability of rainfall simulators as a research tool on urban sealed surfaces – a review

Rainfall simulators can be a useful research tool for some purposes but are quite unsuitable for others. They have been useful in soil erosion and infiltration studies for over eight decades, but the possibility of using a rainfall simulator in urban nonpoint source pollution involving urban non-erodible surfaces has not been fully explored. In this review, the versatility of different rainfall simulators of varying sizes, configurations and styles used in the past two decades are appraised for possible adaptation to urban sealed surfaces. Recommended criteria for detailed rainfall simulator reporting are also outlined.

EDITOR M.C. Acreman

ASSOCIATE EDITOR not assigned     

A review of: “Quantitative hydrogeology—groundwater hydrology for engineers”

Abstract

by Ghislain de Marsily, Academic Press, vii+440 pp. U.S. $29.95 (ISBN 0-12-208916-2) 1986.     

Lagrangian coherent structures in the California Current System – sensitivities and limitations

We report on numerical experiments to test the sensitivity of Lagrangian coherent structures (LCSs), found by identifying ridges of the finite-time Lyapunov exponent (FTLE), to errors in two systems representing the California Current System (CCS). First, we consider a synthetic mesoscale eddy field generated from Fourier filtering satellite altimetry observations of the CCS. Second, we consider the full observational satellite altimetry field in the same region. LCS are found to be relatively insensitive to both sparse spatial and temporal resolution and to the velocity field interpolation method. Strongly attracting and repelling LCS are robust to perturbations of the velocity field of over 20% of the maximum regional velocity. Contours of the Okubo–Weiss (OW) parameter are found to be consistent with LCS in large mature eddies in the unperturbed systems. The OW parameter is unable to identify eddies at the uncertainty level expected for altimetry observations of the CCS. At this expected error level, the FTLE method is reliable for locating boundaries of large eddies and strong jets. Small LCS features such as lobes are not well resolved even at low error levels, suggesting that reliable determination of lobe dynamics from altimetry will be problematic.     

Comparative hydrogeology – reference analysis of groundwater dynamics from neighbouring observation wells

ABSTRACT

Groundwater level fluctuations are caused by spatial and temporal superposition of processes within and outside the aquifer system. Most of the subsurface processes are usually observed on a small scale. Upscaling to the regional scale, as required for future climate change scenarios, is difficult due to data scarcity and increasing complexity. In contrast to the limited availability of system characteristics, high-resolution data records of groundwater hydrographs are more generally available. Exploiting the information contained in these records should thus be a priority for analysis of the chronical lack of data describing groundwater system characteristics. This study analyses the applicability of 63 indices derived from daily hydrographs to quantify different dynamics of groundwater levels in unconfined gravel aquifers from three groundwater regions (Bavaria, Germany). Based on the results of two different skill tests, the study aids index selection for different dynamic components of groundwater hydrographs.     

A review of: “Exercises in astronomy”

Abstract

By J. Kleczek. D. Reidel Publishing Company, xxiii+339 pp., us$ 64 (ISBN 90-277-2409-1), Paperback Edition US$19.50 (ISBN 90-277-2423-7).     

A review of: “Rotating fluids in geophysics”

Abstract

By P. H. Roberts and A. M. Soward (Editors). Academic Press Inc. (London) Ltd, $36.25 (£17.50). (ISBN 0 12 589650 6.)     

A review of: “Advances in Helio- and asteroseismology”

Abstract

Edited By J. Christensen-Dalsgaard and S. Frandsen. D. Reidel, xxi + 604 pp., Hardb. Dfl. 230.00, us$ 109.00 (ISBN 90-277-2614-0), Paperb. Dfl. 95.00 US$ 49.00 (ISBN 90-277-2615-9).     

To be or not to be multi-Gaussian? A reflection on stochastic hydrogeology

The multivariate Gaussian random function model is commonly used in stochastic hydrogeology to model spatial variability of log-conductivity. The multi-Gaussian model is attractive because it is fully characterized by an expected value and a covariance function or matrix, hence its mathematical simplicity and easy inference. Field data may support a Gaussian univariate distribution for log hydraulic conductivity, but, in general, there are not enough field data to support a multi-Gaussian distribution. A univariate Gaussian distribution does not imply a multi-Gaussian model. In fact, many multivariate models can share the same Gaussian histogram and covariance function, yet differ by their patterns of spatial continuity at different threshold values. Hence the decision to use a multi-Gaussian model to represent the uncertainty associated with the spatial heterogeneity of log-conductivity is not databased. Of greatest concern is the fact that a multi-Gaussian model implies the minimal spatial correlation of extreme values, a feature critical for mass transport and a feature that may be in contradiction with some geological settings, e.g. channeling. The possibility for high conductivity values to be spatially correlated should not be discarded by adopting a congenial model just because data shortage prevents refuting it. In this study, three alternatives to a multi-Gaussian model, all sharing the same Gaussian histogram and the same covariance function, but with different continuity patterns for extreme values, were considered to model the spatial variability of log-conductivity. The three alternative models, plus the traditional multi-Gaussian model, are used to perform Monte Carlo analyses of groundwater travel times from a hypothetical nuclear repository to the ground surface through a synthetic formation similar to the Finnsjön site in Sweden. The results show that the groundwater travel times predicted by the multi-Gaussian model could be ten times slower than those predicted by the other models. The probabilities of very short travel times could be severely underestimated using the multi-Gaussian model. Consequently, if field measured data are not sufficient to determine the higher-order moments necessary to validate the multi-Gaussian model — which is the usual situation in practice — other alternative models to the multi-Gaussian one ought to be considered.     

Sustainable sanitation systems for low income urban areas – A case of the city of Bulawayo,Zimbabwe

Lack of basic sanitation systems threaten environmental and human health in low income urban communities. In 2005, the Government of Zimbabwe carried out a cleanup exercise in urban areas involving the destruction of illegal structures which left many people homeless. As a solution to this problem, the government embarked on an extensive housing construction exercise on unserviced land; the ‘Garikai/Hlalani Kuhle’ development programme. The objective of this paper was to investigate the sanitation status in one such area (Cowdray Park Extension, Bulawayo) and determine a sustainable sanitation system for the improved collection of wastewater from the unserviced low income urban area. The study was carried out between October 2010 and February 2011. The sanitation status as well as the residents’ preferences for improved sanitation and the economic set up of the community for the study area was determined through use of questionnaires to the residents. The local authority was then consulted to recommend sanitation facilities and system for the area that met regulatory requirements. A literature study identified sanitation options that were applicable to low income and high density urban areas. The baseline survey found that 61% of the people in the study area lacked sanitation facilities and practiced open defecation. The majority of the residents (70%) preferred ‘flush and discharge’ system sanitation facilities, which was in line with the local council’s requirements. On-site sanitation options were found not to be feasible as per the council regulations and the findings of the literature study, for areas with a high density of houses. Therefore a sewerage system was designed using the conventional sewerage design approach as well as the simplified sewerage design approach in order to determine the collection system that would best meet the needs of the community. In conclusion, the community was in dire need of a sanitation system and a waterborne offsite sanitation system was found to be a feasible option. The simplified sewerage system was found to deliver the same hydraulic benefits for collecting wastewater as the conventional but was 33% cheaper to construct and hence more affordable for the community. It was recommended that stringent environmental monitoring of the sanitation system be put in place to minimise any potential environmental impacts.     

Ionospheric quiet-day currents and their effects on the interpretation of upper mantle conductivity – A review

A review of ionospheric currents,the external part of geomagnetic solar quiet (Sq)variation and the internal part of the induced currentwithin the Earth, has been carried out.The theoretical background has been reviewed,and the method of analysis, specificallythe spherical harmonic analysis (SHA),is presented. Various works are reviewed andfully discussed. It has been noted that anew model of the Sq current system could beused to obtain a mantle electrical conductivityprofile for hemispheres. It is suggested thatfurther research work be carriedout in other hemispheres using similarmodels for more robust interpretations.     

A review of: “Turbulence and random processes in fluid mechanics”

Abstract

by M. T. Landahl and E. Mollo-Christensen, Cambridge University Press, vi+154 pp., ?34.50 (ISBN (0-521-26306-9) 1986.     

A decade of Predictions in Ungauged Basins (PUB)—a review

Abstract

The Prediction in Ungauged Basins (PUB) initiative of the International Association of Hydrological Sciences (IAHS), launched in 2003 and concluded by the PUB Symposium 2012 held in Delft (23–25 October 2012), set out to shift the scientific culture of hydrology towards improved scientific understanding of hydrological processes, as well as associated uncertainties and the development of models with increasing realism and predictive power. This paper reviews the work that has been done under the six science themes of the PUB Decade and outlines the challenges ahead for the hydrological sciences community.

Editor D. Koutsoyiannis

Citation Hrachowitz, M., Savenije, H.H.G., Blöschl, G., McDonnell, J.J., Sivapalan, M., Pomeroy, J.W., Arheimer, B., Blume, T., Clark, M.P., Ehret, U., Fenicia, F., Freer, J.E., Gelfan, A., Gupta, H.V., Hughes, D.A., Hut, R.W., Montanari, A., Pande, S., Tetzlaff, D., Troch, P.A., Uhlenbrook, S., Wagener, T., Winsemius, H.C., Woods, R.A., Zehe, E., and Cudennec, C., 2013. A decade of Predictions in Ungauged Basins (PUB)—a review. Hydrological Sciences Journal, 58 (6), 1198–1255.     

Significance of Vibrio species in the marine organic carbon cycle—A review

The genus Vibrio,belonging to Gammaproteobacteria of the phylum Proteobacteria,is a genetically and ecologically diverse group of heterotrophic bacteria,that are ubiquitous in marine environments,especially in coastal areas.In particular,vibrios dominate,i.e.up to 10%of the readily culturable marine bacteria in these habitats.The distribution of Vibrio spp.is shaped by various environmental parameters,notably temperature,salinity and dissolved organic carbon.Vibriospp.may utilize a wide range of organic carbon compounds,including chitin(this may be metabolized by most Vibrio spp.),alginic acid and agar.Many Vibrio spp.have very short replication times(as short as～10 min),which could facilitate them developing into high biomass content albeit for relatively short durations.Although Vibriospp.usually comprise a minor portion(typically~1%of the total bacterioplankton in coastal waters)of the total microbial population,they have been shown to proliferate explosively in response to various nutrient pulses,e.g.,organic nutrients from algae blooms and iron from Saharan dust.Thus,Vibrio spp.may exert large impacts on marine organic carbon cycling especially in marginal seas.Genomics and related areas of investigation will reveal more about the molecular components and mechanisms involved in Vibrio-mediated biotransformation and remineralization processes.     

A review of: “Transport and energy conversion in the heliosphere”

Lectures given at the CNRS Summer School on Solar Astrophysics, Oleron, France, 25-29 May 1998, edited by P.-P. Rozelot, L. Klein and J.-C. Vial, Lecture Notes in Physics: Vol. 553, Springer-Verlag Berlin Heidelberg New York, 2000. VIII+214 pp., DM 104.00, hardbound (ISBN 3-540-67595-7)     

A review of: “Advances in geophysics,vol. 21”

Abstract

Edited by Barry Saltzman. Academic Press Inc. (London) Ltd., 1979. 432 pp. (527.20) (ISBN 0 12018821 X).     

A review of: “Solar phenomena in stars and stellar systems”

Abstract

edited by R. M. Bonnet and A. K. Dupree. D. Reidel Publishing Company (1981), 584 pp. Dfl. 135/US$69.50. (ISBN 90 277 1275 1)     

Methodology to set trigger levels in an urban drainage flood warning system – an application to Jhonghe,Taiwan

A wireless water-level monitoring system for an urban drainage flood warning is developed, and stations equipped with pressure sensors are installed to monitor water levels. The water levels for flood warning are investigated. Two stages of warning water level for “larger” conduits are set based on the rate of rising water levels. In a similar way, only one stage of the warning water level is set for “smaller” conduits. The average rates of rising water levels for different scenarios are estimated using the US EPA Storm Water Management Model (SWMM). When evaluating the impact of flooding, the outflows from manholes simulated by the SWMM are used as sources for a two-dimensional overland flow simulation. The integrated system is successfully executed in Jhonghe, New Taipei City, Taiwan, which has experienced urban drainage floods. Therefore, this system can provide urban drainage flood warnings to the authorities to take disaster reduction measures.