Branch Stream Research Articles

하천의 생태적 복원을 위한 식생학적 연구 - 남한강 육상식물, 토양을 중심으로 -

This study was designed to present a river model with an aim at restoring the ecosystem and improving the landscape along the urban rivers on the basin of the Namhan river, a core life channel for the National Capital region. The revelation of botanical status, transition trend and correlation of plants might lead to providing the urban river restoration projects and ecological river formation projects with basic data for a model of ideal aquatic ecology and landscape. The outcomes of this study could be summed up as follows: 1. Communities of Juglans mandshurica, Cornus controversa and Fraxinus mandshurica constitute the main portion of flora at or around uppermost branch streams of the River Namhanis harbored mainly in and around small brooks 2. Typical terrestrial forest communities formed around the River Namhan are composed mainly of Larix leptolepis, Pinus rigida, planned forestation of Pinus koraiensis, Quercus acutissima, Quercus variabilis and Pinus densiflora. 3. The analysis into terrestrial environment of plant communities showed a high content of , typical communities found in the artificially disturbed land Finally, it seems also desirable to continue to make every exertion to explore the relationship between fluvial and terrestrial ecologies with a purport of building up a model of natural streams in urban area based on the surveyed factors for plant life, forest communities, soil and landscape and, moreover, on the forecasting for overall influences derived from the relation upon the ecosystem.

Gevninge – leddet til Lejre

Gevninge – leddet til Lejre

Distribution, partitioning and sources of polycyclic aromatic hydrocarbons in Daliao River water system in dry season, China

Eighteen polycyclic aromatic hydrocarbons (PAHs) were analyzed in 29 surface water, 29 suspended particulate matter (SPM), 28 sediment, and 10 pore water samples from Daliao River water system in dry season. The total PAH concentration ranged from 570.2 to 2318.6 ng L −1 in surface water, from 151.0 to 28483.8 ng L −1 in SPM, from 102.9 to 3419.2 ng g −1 in sediment and from 6.3 to 46.4 μg l −1 in pore water. The concentration of dissolved PAHs was higher than that of particulate PAHs at many sites, but the opposite results were generally observed at the sites of wastewater discharge. The soluble level of PAHs was much higher in the pore water than in the water column. Generally, the water column of the polluted branch streams contained higher content of PAHs than their mainstream. The environmental behaviors and fates of PAHs were examined according to some physicochemical parameters such as pH, organic carbon, SPM content, water content and grain size in sediments. Results showed that organic carbon was the primary factor controlling the distribution of the PAHs in the Daliao River water system. Partitioning of PAHs between sediment solid phase and pore water phase was studied, and the relationship between log K oc and log K ow of PAHs on some sediments and the predicted values was compared. PAHs other than naphthalene and acenaphthylene would be accumulated largely in the sediment of the Dalaio River water system. The sources of PAHs were evaluated employing ratios of specific PAHs compounds and different wastewater discharge sources, indicating that combustion was the main source of PAHs input.

Modeling sediment transport in river networks

A dynamical model is proposed to study sediment transport in river networks. A river can be divided into segments by the injection of branch streams of higher rank. The model is based on the fact that in a real river, the sediment-carrying capability of the stream in the i th segment may be modulated by the undergone state, which may be erosion or sedimentation, of the i − 1 th and i th segments, and also influenced by that of the i th injecting branch of higher rank. We select a database about the upper-middle reach of the Yellow River in the lower-water season to test the model. The result shows that the data, produced by averaging the erosion or sedimentation over the preceding transient process, are in good agreement with the observed average in a month. With this model, the steady state after transience can be predicted, and it indicates a scaling law that the quantity of erosion or sedimentation exponentially depends on the number of the segments along the reach of the channel. Our investigation suggests that fluctuation of the stream flow due to random rainfall will prevent this steady state from occurring. This is owing to the phenomenon that the varying trend of the quantity of erosion or sedimentation is opposite to that of sediment-carrying capability of the stream.

Investigating habitat value to inform contaminant remediation options: Case study

Habitat valuation methods were implemented to support remedial decisions for aquatic and terrestrial contaminated sites at the East Tennessee Technology Park (ETTP) on the US Department of Energy (DOE) Oak Ridge Reservation in Oak Ridge, TN, USA. The habitat valuation was undertaken for six contaminated sites: Contractor's Spoil Area, K-901-N Disposal Area, K-770 Scrapyard, K-1007-P1 pond, K-901 pond, and the Mitchell Branch stream. Four of these sites are within the industrial use area of ETTP and two are in the Black Oak Ridge Conservation Easement. These sites represent terrestrial and aquatic habitat for vertebrates, terrestrial habitat for plants, and aquatic habitat for benthic invertebrates. Current and potential future, no-action (no remediation) scenarios were evaluated primarily using existing information. Valuation metrics and scoring criteria were developed in a companion paper, this volume. The habitat valuation consists of extensive narratives, as well as scores for aspects of site use value, site rarity, and use value added from spatial context. Metrics for habitat value were expressed with respect to different spatial scales, depending on data availability. There was significant variation in habitat value among the six sites, among measures for different taxa at a single site, between measures of use and rarity at a single site, and among measures for particular taxa at a single site with respect to different spatial scales. Most sites had aspects of low, medium, and high habitat value. Few high scores for current use value were given. These include: wetland plant communities at all aquatic sites, Lepomid sunfish and waterbirds at 1007-P1 pond, and Lepomid sunfish and amphibians at K-901 pond. Aquatic sites create a high-value ecological corridor for waterbirds, and the Contractor's Spoil Area and possibly the K-901-N Disposal Site have areas that are part of a strong terrestrial ecological corridor. The only example of recent observations of rare species at these sites is the gray bat observed at the K-1007-P1 pond. Some aspects of habitat value are expected to improve under no-action scenarios at a few of the sites. Methods are applicable to other contaminated sites where sufficient ecological data are available for the site and region.

The Patterns and Meaning of a Great Lake in West Africa

The cartographical history of Africa has often left much to the imagination. The idea of a great inland lake along the Niger River in West Africa, for example, has had a rich tradition in written accounts and on maps from Ptolemy onwards. One tendency was to dismiss the notion that any such body of water existed; another was to find divers ways of reconciling tradition and the sparse scattering of new 'facts' that reached European mapmakers. The fundamental problem was ignorance about the hydrology of the interior of Africa, especially in the region of the Niger River. Not until the nineteenth century was the presumed connection between the Niger and Senegal rivers laid to rest, together with the older view that the Niger flowed underground through the eastern highlands to the Nile. Only then was the Niger's actual course established, flowing first east and then, after a great bend, south to debouche into the Gulf of Guinea.1 While the attention of historians focused mostly on the African coastline and the eastern lakes, the early maps of West Africa had regularly showed a prominent inland lake on the southern edge of the Sahara. The cartographical history of this lake has invited further investigation. In this paper we ask how did the image originate, by what physical feature could it have been inspired, and why should it have been considered important in the history of the sub-Saharan region. We approached the issue by looking at four hundred primary maps dating from 900 to 1900. The analysis of this database confirmed that one of the most consistent features throughout the archival record was the image of a lake in West Africa within the region of the middle Niger River.2 From maps on which the lake was named (which was not always the case), we have identified numerous toponyms, including Nigrite Palus, Nilides Palolus, Wangara, Sigisma, Guber, Guarda, Bogs of Guarda, Maberia, Nigris Morass, Dibbie Sea, Lake Dibbie and Lake Debo. This analysis has led to the conclusion that whatever the feature was called, and whatever shape it was given, the mapmakers were each attempting to portray a common physical reality. That entity was the fluctuating area of lakes and branching streams in the middle course of the Niger River, between Djenne and Tombouctou known today as the Inland Niger Delta (Fig. 1). The inland delta, as a unique local feature, is shown on modern maps at best as a limited area of swamp at the southern edge of the Sahara. It is rarely given a name and remains mostly unnoticed in the world's view of modern Africa. Yet, the true meaning of this great wetland lies in the fact that it was once home to a thriving civilization centred on an array of specialized urban settlements near Lake Debo, in the vicinity of modern Djenne (old JenneJeno).3 For more than fifteen hundred years Jenne-Jeno had been the focus of one of the

Recognition of areas of anomalous concentration of potentially hazardous elements by means of a subcatchment-based discriminant analysis of stream sediments

The statistical technique of discriminant analysis associated with the calculation of an information coefficient has been applied to the concentrations of 37 chemical elements for calculating the mixing of stream sediments of different origin in the Mignone river basin. Discriminant analysis has been based on sample catchment basins (SCBs), defined as the part of the drainage basin between two consecutive sampling points along the same stream branch, and on the identification of 4 different litho-geochemical groups. This approach, has been used to define the membership probability values for every sample by applying Bayes' rule and calculating posterior probability. The grade of uncertainty for each group assignment has been evaluated by using an information coefficient, based on a classification entropy index, and running a procedure analogue to that used for processing membership values in fuzzy analysis. The maximum theoretical concentration that can be expected in soils near the sampling point ( enhanced concentration) has then been calculated from both the measured and the membership values by introducing a specific enhancement function. Theoretical background concentrations at every sampling point have been also calculated by weighting the average value of concentration in each group with the membership values for each sample. These have been successively compared with the measured and enhanced concentrations to identify anomalous areas. The distribution maps of Arsenic and Vanadium in the Mignone River basin (central Italy) have been drawn accordingly to this technique, leading to the identification of areas of potential risk for human health.

Analysis of seasonal water pollution based on rainfall feature at Anyang river basin in Korea

To determine selected water pollution parameters of the Anyang River (one of the biggest contributory branches of the Han River in Korea) and its main tributaries, the geological and topographical and rainfall features in its basin were investigated, and the resulting data were tabulated. Samples were collected at the upper, mid and down parts of the Anyang River and its branches and were analyzed based on biochemical and chemical methods, Korean biotic index (KBI) and Saprobien systems. Selected parameters of concern include BOD, heavy metals, nonpoint pollution and sewage discharge. The Anyang River basin has a torrential heavy rainfall; however, the rate of rainfall significantly varies from season to season. Water pollution levels in the dry season increase dramatically. The mainstream of the Anyang River is classified as fifth grade polysaprobic water according to Saprobien system. In addition, the biotic index is over 2.5 in overall. General pollution at the junction of the Anyang River and each branch stream varies. Possible countermeasures to improve the water quality of the river include intercept the non-treated waste water and sewage at the Anyang River junction and each branch stream, enforcement of water management during the rainy season, and continuous investment on environmental restoration.

INFLUENCE DISTRIBUTIONS OF ACID DEPOSITION IN MOUNTAINOUS STREAMS ON A TALL CONE-SHAPED ISLAND, YAKUSHIMA

Yakushima, facing at 800 km east of Shanghai in the East China Sea, is a tall cone-shaped island with seven exceeding 1800 m peaks. The prevailing winds of westrelie on the island blow mostly fromnorthwest and west. It has been exposed to acid rain of pH 4.7 and precipitation 8000 mm in the central highland. More than sixty mountainous streams were observed at downstream points seasonally for past twelve years. The alkalinity of streamwaters in the southwestern part was lower than others. The concentrations of SO42- in the northwestern part were higher than others. The high concentrations of SO42-, dissolved SiO2 and other ions in the southwestern part with high canopy density of evergreen broadleaved forest were caused by higher air temperature, less rainfall and higher evapotranspiration than other parts. The alkalinity, pH and EC in the catchment of north stream in the upstream branch of the R. Anboh became lower than those in the catchment of south stream. The height of catchment boundaries, the direction of the main axis of a catchment and the prevailing winds govern the influence of acid deposition on water quality of branch streams.

Summer drought disturbance on plant detritus decomposition processes in three River Tirso (Sardinia, Italy) sub-basins

Here, we study the variation patterns of detritus decomposition along a river continuum in a Mediterranean type river basin, and the influence of summer drought disturbance on this pattern. The study was carried out in three 4th order sub-basins (hereafter referred to as Assolo, Laconi and Olzai) of the river Tirso basin (Sardinia, ITALY), with one study site per stream order in each sub-basin (4 stream orders × 3 sub-basins = 12 study sites). The three sub-basins were selected according to their exposure to summer drought, Assolo being the most exposed and Laconi the least exposed. Reed (Phragmites australis (Cav.) Steudel) detritus decomposition was studied during the fall and spring periods, utilising the leaf packs technique with 3 sampling dates and 8 replicate packs per sample in each period. At all sites, the stream width was recorded fortnightly for one year. Overall, the reed leaf packs underwent rapid decomposition in the river Tirso basin (k=0.0193 d−1), but very high variation was observed among leaf pack decomposition rates (C.V. = 112.7%). Seasons, sub-basins, and stream orders accounted for 88% of the total variance observed (Three Way ANOVA). The decomposition rate was significantly higher in spring than in fall, in the Laconi sub-basin than in the Olzai and Assolo sub-basins, and in 4th order streams than in 2nd and 3rd. Decomposition rates were also higher at relatively undisturbed sites than at the study sites exposed to complete summer desiccation (e.g., 2nd, 3rd, 4th in the Olzai sub-basin; 1st, 2nd, 3rd in the Assolo sub-basin). The strongest effects of summer drought disturbance occurred at the lowest order stream branches (i.e., 1st and 2nd order) suggesting that the resilience of detritus decomposition processes to the disturbance arising from Mediterranean type climates increases with stream order.

A Parallel Genetic Algorithm/Simulated Annealing Algorithm for Synthesizing Multistream Heat Exchanger Networks

A mathematical model for synthesizing multistream heat exchanger networks is presented which eliminates the unreasonable assumption on isothermal mixing of stream branches, hence the model is more rigorous and practical. The model becomes more complex due to its large scale dimensions, nonlinear constraints and nonconvexity of objective function. Multiple local optima might also exist. It is difficult to use traditional algorithms to find the global optimization solution of this mathematical model. A Parallel Genetic Algorithm/Simulated Annealing Algorithm (PGA/SA) with the strategy of inter-subpopulation crossover and migration, generation of initial feasible population and infeasible individual repair approach is proposed to obtain the global optimization solution with larger probability. Some computational examples from literatures and an industrial project show that the proposed mathematical model and algorithm are feasible and effective.

Transient analytic elements for periodic Dupuit–Forchheimer flow

A new analytic element formulation is presented for the simulation of transient, periodic Dupuit–Forchheimer flow. Equations are presented for the discharge potential of periodic wells, line-sinks, and circular area-sinks; all discharge potentials are written in separated form as the product of a function of space and a periodic function of time. Boundary conditions are represented with Fourier series consisting of an arbitrary number of terms. The obtained solution is analytic; water levels in streams are met at collocation points along the stream exactly and continuously through time. Equations are derived for ‘influence factors’, which represent characteristic lengths over which the periodic change of a well or line-sink has a significant influence on the head variation in the aquifer. Possible applications of the proposed method include the modeling of seasonal fluctuations in head and baseflow, and the estimation of aquifer properties from measured head variations. A hypothetical example is presented and the variation of the head in the aquifer and the inflow along a stream branch are evaluated.

Paleoenvironmental changes across the Cretaceous/Tertiary boundary in the northern Clarence valley, southeastern Marlborough, New Zealand

Strata outcropping in Mead and Branch Streams, northern Clarence valley, provide important records of pelagic‐hemipelagic sedimentation through the Cretaceous‐Paleocene transition in a southern high‐latitude, upwelling system flanking a carbonate platform. The two stream sections, <10 km apart along‐strike, comprise similar stratigraphic successions with differences mainly due to Branch Stream being situated closer to land (outer shelf to upper bathyal) than the mid‐bathyal Mead Stream section. Age control is based on foraminiferal and radiolarian biostratigraphy. A Cretaceous/Tertiary (K/T) boundary clay is not preserved in either section. The siliceous microfossil record indicates that basal Paleocene sediments at Branch Stream, although slightly enriched in Ni and Cr, were deposited after a significant relative sea‐level fall. A basal Paleocene claystone at Mead Stream is not enriched in K/T impact‐derived elements and was probably deposited after sea‐level fall. Earliest Paleocene sediment may be preserved as burrow fill in an uppermost Cretaceous bioturbated zone, which is enriched in Ni and Cr and contains a foraminiferal assemblage indicative of Paleocene Zone P0. Zone PO‐Pα foraminiferal assemblages within the basal Paleocene sediments in both sections indicate that sea level fell within 100 000 yr of the K/T boundary event. The K/T boundary at both sites coincides with an abrupt change in lithofacies from calcareous to siliceous ooze. Biosiliceous sediment dominates the sedimentary record over the first 1.5 m.y. of the Paleocene, which corresponds to 45 m of strata at Branch Stream and 20 m in the more condensed Mead Stream section. A trend from diatom‐poor to diatom‐rich and finally radiolarian‐rich microfossil assemblages over the lower 5 m of Paleocene strata at Branch Stream is consistent with progressive deepening at the landward margin of an upwelling zone. A second regressive pulse at c. 64.5 Ma, followed by prolonged transgression from 5–50 m above the K/T boundary, is inferred from an initial increase in the frequency of mudstone beds, followed by a similar trend from diatom‐poor to radiolarian‐rich microfossil assemblages. Within the upper part of this interval, an increase in carbonate marks a return to lithofacies, and probably also paleodepth, equivalent to the underlying Cretaceous. In the deeper Mead Stream section, variation in diatom and radiolarian assemblages is mainly due to variable preservation in highly recrystallised lithologies. High overall abundance and little change in paleoproductivity indicators (Ba, δ13C) indicate that high biological productivity continued across the K/T boundary and through the biosiliceous episode. Siliceous plankton thrived in the Marlborough upwelling zone during the early Paleocene. Fluctuations in abundance and lithofacies can be related to significant changes in sea level, which may be the result of local tectonic or global climate changes. The delayed recovery of calcareous plankton after mass extinction at the K/T boundary, in both outer neritic and bathyal settings, indicates a relatively cool oceanic regime for the first 1.5 m.y. of the Paleocene.

The Cretaceous/Tertiary boundary event in New Zealand: Profiling mass extinction

Of over 20 known Cretaceous/Tertiary (K/T) boundary sections in the New Zealand region, 6 in the northern South Island were selected for detailed biostratigraphic and paleoenvironmental study because of their apparent stratigraphic completeness and the range of depositional environments represented. These sections represent the only known southern high‐latitude (55–60°S) transect of the K/T boundary transition from continental slope to terrestrial mire. The K/T boundary is marked by deposition of an impact fallout layer in four of these sections, and a disconformity representing a hiatus of < 100 000 yr in the remaining two sections (Mead and Branch Streams). In the terrestrial Moody Creek Mine and shallow marine mid‐Waipara sections, rapid and widespread destruction of forests is shown by abrupt replacement of mixed forest pollen and spore assemblages by assemblages dominated by few species of ground ferns. Foraminiferal and radiolarian biostratigraphy indicates that within 100 000 yr these ferns were replaced by a cool‐temperate conifer‐dominated assemblage that persisted until c. 63.5 Ma. In the marine sections, an abrupt decrease in carbonate content reflects a major decline in carbonate production associated with mass extinction of calcareous plankton, although several smaller species of planktic foraminifera persist for c. 100 000 yr into the Paleocene. In four sections in Marlborough (Flaxbourne, Woodside, Mead, and Branch), which represent a transect across a coastal upwelling zone, paleoproductivity proxies (excess SiO2, excess Ba, Ba/Al, δ13 C) indicate that the decline in calcareous plankton was partly offset by sustained siliceous plankton productivity. Extinctions of thermophilic foraminifera, survival of cosmopolitan foraminifera, and expansion of diatoms and spumellarian radiolarians indicate that pronounced cooling occurred across the K/T boundary. A subsequent decline in planktic foraminifera and in carbonate content, associated with a progressive increase in siliceous plankton productivity, indicates that further cooling resulted in dominantly biosiliceous sediment being deposited in the core of the Marlborough upwelling zone from c. 64.9 to 63.5 Ma. The onset of this biosiliceous event at c. 64.9 Ma and a later major increase in biogenic silica in the deep‐water sections (Flaxbourne, Woodside) at c. 64.6 Ma are correlated with sea‐level falls in the shelf section (Branch) and are also linked to eustatic events recorded in Europe and North and Central America. These early Paleocene regressive events within a cool climatic regime are the probable cause of incomplete K/T boundary records in most of New Zealand. It remains uncertain if they are directly related to the K/T bolide impact, the short‐term effects of which may have disrupted the global climate system for millions of years, or are related to other factors such as tectonism or fluctuating CO2 emissions from Deccan volcanism.

Seasonal change of mineral precipitates from the coal mine drainage in the Taebaek coal field, South Korea.

The seasonal change of the precipitates from the acid coal mine drainages is remarkable in the Taebaek coal field in the middle eastern part of the Korean peninsula. The mineral precipitates in the creeks show various colors such as brownish yellow, white, and reddish brown, depending on the chemical conditions of stream waters. The brownish yellow precipitate consist maily of schwertmannite, the white one of poorly crystalline Al-sulfate, and the reddish brown one of ferrihydrite. Neutralization of acid mine drainage took place by mixing with unpolluted waters and/or buffering by dissolution of carbonate or aluminosilicates. The main factors leading to the seasonal change of precipitates are precipitation of hydroxide mineral, water mixing from adjacent unpolluted branch streams, and water-rock interaction.

Performance analysis and interoperability issue of consolidation algorithms in point‐to‐multipoint ABR services

AbstractIn this paper we propose a performance analysis of the consolidation algorithms in point‐to‐multipoint ABR services in ATM network. We also present a new efficient consolidation algorithm, which overcomes some drawbacks of the previous works. The performance of the previous works and our proposed consolidation algorithms are analysed mathematically. General equations for calculating the response time and allowed cell rate of the source are derived. The derived equations show relatively good agreement with simulation results and can be applied for using in various network topologies. In addition, the interoperability issue in multicast available bit rate (ABR) is investigated. It is found that the branch points implemented with different consolidation algorithms can work interoperably. It is concluded from the simulation results that the performance of the point‐to‐multipoint ABR services is dominated by the most upper stream branch point (the nearest one to the source), therefore, in order to avoid the consolidation noise and get a faster response in the network, the most upper stream branch point has to be implemented with a high accuracy consolidation algorithm while the lower stream branch point(s) should be implemented with a fast response consolidation algorithm with a less degree of complexity. Copyright © 2002 John Wiley &amp; Sons, Ltd.

Paleo‐equilibrium line altitude estimates from late Quaternary glacial features in the Inland Kaikoura Range, South Island, New Zealand

A reconnaissance investigation of glacial features in the Inland Kaikoura Range (IKR), South Island, New Zealand, confirms that over 30 km of the length of the range, with a maximum elevation of 2885 m, has been extensively glaciated in the past, in contrast to previous reports. Identified glacial features include cirques, lateral moraines, moraine fragments and associated features, and rock glaciers. Up to five glacial advances have been identified in any one catchment in the range, with the most complete sequence found in Branch Stream, which drains the steep southeastern flank of the highest portion of the range. The lateral moraines of Branch Stream are impressive; they range in elevation from c. 1700 to 1200 m, and, because of their large size and relatively good state of preservation, they are interpreted to be of late Otiran age. Glacial features that are less well preserved and more fragmentary are found at lower elevations in other catchments (e.g., Dart, Muzzle, and Bluff Streams), and are here inferred to be of early‐mid Otiran age. The lack of preservation of older glacial landforms is attributed to the steep, unstable terrain of the IKR generated by the relatively high uplift rate (c. 5 mm/ yr), and consequent high erosion rate in the range, which is located in the hanging wall of the active Clarence Fault. A sequence of paleo‐equilibrium line altitudes (paleo‐ELAs) for the past glaciers in the IKR have been derived using cirque floor elevations, accumulation‐area ratios (AARs) and interpolated estimates, and give snowline depressions below the present (2530 m) of 830 m for the early‐mid Otiran, 740 m for late Otiran, 575 m for final Otiran, 450 m for Late Glacial, 270 m for Neoglacial, and 150 m for the Little Ice Age. Because glacial features in the IKR have yet to be directly dated, these age estimates should be regarded as interpretive in nature and are based solely on relative size, elevation, sequence position, and degree of preservation. The paleo‐ELAs have been normalised to a southerly aspect using a correction established in the northern Southern Alps that has yet to be tested in the IKR. Correcting for accrued uplift over the past c. 18 000 yr conceivably provides an additional c. 90 m of depression, suggesting a total ELA depression of as much as c. 830 m during the late Otiran compared to modern climate. The paleo‐ELA depression estimates for the IKR appear to be similar to estimates calculated in other areas in the South and North Islands. Evidence of glacial features in the IKR, and the apparent similarity of ELA depressions in the range with that elsewhere in New Zealand, suggests that past climate fluctuations in the IKR have been, to at least some degree, “in harmony” with those throughout the remainder of the country.

Eroded Material Considered a Pollutant

Ross Adams owned 76 acres (31 ha) of land in the North Georgia mountains. David and Barbara Driscoll owned 5 acres (2 ha) adjacent to Adams's property, and Ruel and Patricia Galbreath owned 2 acres (0.8 ha) adjacent to the Driscolls' property. The Spiva Branch stream flows downhill from Adams's property through a pond on the Driscolls' property and then through another pond on the Galbreaths' property before merging with the Nottely River. Adams harvested timber on his property from March to November 1995. During the harvest, he cut and graded roads, installed storm pipes, and cut and removed timber. The harvest and development caused erosion of mud, sand, and other materials on his property. Stormwater washed mud, silt, and other materials from Adams's property into the Spiva Branch stream and then into the Driscolls' and Galbreaths' ponds. Adams failed to seek proper approval from any federal, state, or local government agency before starting to work on his property. The Driscolls and Galbreaths sued Adams for violation of the Clean Water Act (CWA). The trial court ruled against them, concluding that the requirement of a National Pollutant Discharge Elimination System permit was impossible here. On appeal, Adams argued that the discharges did not fall within the scope of prohibited pollutant discharges under the CWA. But, the court said that the definition of “pollutant” in the CWA was broad, including rock, sand, cellar dirt, and industrial, municipal, and agricultural waste. The court also said that when rain water flows from a site on which land‐disturbing activities have been conducted, it falls within the description of a pollutant. The trial court decision was reversed, and the case sent back for further proceedings.

Fluorimetric determination of bromate by ion-exchange separation and post-column derivatization

For the determination of bromate in drinking water a stopped-flow post-column reaction was developed following the separation of bromate from the matrix by an anion-exchange column. In the post-column reaction the analyte was used to oxidize the azo dye sulfonaphtholazoresorcinol, SNAR, and the residual amount was converted into a fluorescent binuclear complex by an excess of gallium ions. The fluorescence was monitored at 585 nm, with a maximum excitation wavelength at 521 nm. The determination of bromate is based on the decrease of the fluorescence intensity with increasing bromate concentration. The given hydrodynamic parameters and the condition of equal flow rates of the two branch streams at each T-piece have to be considered as an important criterion for the experimental set-up. The volume flows and the concentrations required for the reagent solutions in the influent of each T-piece were determined as a result of batch experiments and theoretical considerations. The limit of detection was 0.28 μg L−1bromate for the flow method, which shows linearity up to 15 μgL−1 bromate.

Algorithm to find the optimal queueing discipline in a system with branching streams of secondary customers

Algorithm to find the optimal queueing discipline in a system with branching streams of secondary customers