ALBERT

Notes: : Autoregressive moving average (ABMA) models have been applied to study the flow series of the karstic springs of La Villa, Fuente Mayor (Spain), and Aliou (France). The theoretical meaning of the parameters involved in the model upon applying it to a simplified scheme of the emptying of a karstic aquifer is first analyzed. The types of transformations necessary to apply these models to the flow series that lack normality and have strong periodic components are also indicated, as are the advantages of this type of model and the physical significance of the parameters obtained, with respect to the standpoint of hydraulics, ranging from rather homogeneous aquifers (La Villa) to extremely karstic (Aliou), including aquifers with intermediate characteristics (Fuente Mayor).

Notes: : The water quality in the Brazos River in Texas is seriously degraded by natural salt pollution in the upper Brazos River. Controlling the natural salt springs and seeps in the Dove Creek area will reduce the chloride concentration in the Brazos River by nearly 45 percent. The brine that is discharged as natural springs and seeps in the Dove Creek area is from two sources: (1) local recharge and (2) deep-basin. A preliminary design of the brine recovery system was developed in this phase of the study. A three-dimensional, finite element model to simulate groundwater flow in anisotropic and heterogeneous media under steady state conditions was developed to assist with the design and evaluation of brine recovery systems in the Dove Creek area. Model simulations indicate that a shallow-well brine recovery system pumping about 56 l/s (2 cfs) of brine will eliminate approximately 45 percent of chloride discharging into the upper Brazos River.

Notes: : It is important to extract and assess low flow recession characteristics for water resources planning in the upper reaches of streams. However, it is very difficult to express synthetically the low flow recession characteristics for a stream flow. In this paper, first a new method of constructing the master recession curve based on the exponential expression is proposed and applied with the restriction that there are no regulation or diversion structures in the upper reaches above the measurement station. Daily precipitation and stream flow were used for the analysis. Second, analysis for a recession constant was conducted and the relationship between the recession constant and low flow and/or geology was qualitatively examined. In conclusion, the application of the proposed method indicated that it is objective and useful for constructing the master recession curve. It became apparent that the recession constant of a master recession curve may be defined as the total index of low flow characteristics. In addition, it was found that baseflow value increases in the order of Paleozoic, Mesozoic, Tertiary, and Quaternary.

Notes: : A model for urban stormwater quality was developed in this study. The basis for the model is the process by which pollutants build up on the watershed surface. For the wet climate of the study site, it was assumed that there exists an interval of time over which the pollutant buildup equals the pollutant washoff (no accumulation of pollutant). The buildup model was represented by a linear function of the antecedent dry time. The buildup function was then linked with a pollutant washoff model represented by a power function of the storm runoff volume. Various time intervals for no net accumulation were tested to calibrate the model. The model was calibrated to observed data for two small urban basins in Baton Rouge, Louisiana, and model results were used to analyze the behavior of phosphorus concentrations in storm runoff from these basins over a long period of time.

Notes: : The Hanging Gardens are a unique feature of Zion National Park. Knowledge of the source and residence time of water discharging from the Hanging Gardens is necessary to help preserve these features. Ground-water chemical and isotopic data distinguish the discharge from seeps and springs into two groups, one of low and one of high conductivity. Water with low conductivity likely originates as recharge near the seeps and springs, and it only interacts with the Navajo Sandstone. High conductivity water, on the other hand, originates as recharge on the tops of plateaus to the east, where it interacts with marine rocks of the Carmel Formation. Carbon dating of these ground waters indicates that the low conductivity water is essentially modern recharge, while the high conductivity water was recharged 1,000 to 4,000 years ago.

Notes: : The 150-kilometer middle reach of the Snake River (middle Snake) in south-central Idaho receives large quantities of water from springs discharging along the north side of the river from the regional Snake River Plain aquifer. Water-quality samples collected from nine north-side springs in April 1994 indicated that springs in the upstream part of the reach had larger concentrations of dissolved solids, dissolved nitrate, total nitrogen, tritium, and heavy isotopes of hydrogen and oxygen than to springs in the downstream part of the reach. Because the spring chemistry varies in the reach, discharge from the springs resulted in a degradation in water quality in some parts of the middle Snake and improvements in water quality in other parts. Depending on the annual discharge in the Snake River, the contribution from the north-side springs represented 33 to 66 percent of the discharge, 32 to 57 percent of the dissolved solids, 26 to 50 percent of the total nitrogen, and 7 to 14 percent of the total phosphorus transported annually from the middle Snake. Synoptic sampling showed that the north-side springs contributed 84 percent of the discharge and 35, 40, and 10 percent of the dissolved solids, total nitrogen, and total phosphorus load, respectively, to the Snake River during the peak of the irrigation season in 1994.

Notes: : Artificial circulation was applied at East Sidney Lake, a small, eutrophic impoundment in New York, to improve the water quality of the reservoir and tailwater. Treatment was successful at both reducing the stability of the reservoir and maintaining higher mean oxygen concentrations in the bottom waters. Discharge waters had lower metals and phosphorus concentrations during treatment years. However, vertical temperature differences, although minimal, were still sufficient to permit chemical stratification and some phosphorus release from the sediments. Frequent mixing events during periods of low stability, and runoff from storm events, also appeared to increase transport of phosphorus into the epilimnion. Overall, treatment did not result in decreases in algal populations or improvements in water clarity.

Notes: : Bivalves are used as bioindicators to assess trends of the chemical quality of coastal and marine environments due to their ability to concentrate chemicals. These shellfish are subject to seasonal physiological changes influencing the chemical concentration. Using quarterly data, we model concentration via linear regression with a biologically based seasonal component. This was applied to cadmium concentration measured in the blue mussel (Mytilus edulis) at three sites in the Seine estuary (Normandy, France). In this case we have a high concentration season from January to June and a “low concentration” season from July to December. This season definition was checked a posteriori, using box-and-whisker plots and a statistical test of comparison of pair-wise adjusted least-squares mean differences, and it appears to be very reasonable. We averaged data by season and across sites. Our final model (R2= 0.846 with N= 27 observations) includes highly significant terms: a season effect, which accounts for 45% of the total variability, a linear and a quadratic time term. Outliers were identified by high Studentized residual values and attributed to bias in the temporal sampling schemes. The methodology developed will further be used with other shellfish and/or other trace elements and organic chemicals.

Notes: : Wildfires in 1988 burned over 2000 square miles of the greater Yellowstone area in Montana and Wyoming in the largest fires in the history of Yellowstone National Park (YNP). A four-year postfire study to estimate fire-related changes in suspended sediment transport on the Yellowstone River and its principal tributary in YNP, the Lamar River, benefitted from a recently completed three-year prefire baseline study. Both studies took daily depth-integrated samples from April through September. Fire-related changes in suspended sediment were distinguished from natural climatic variations by two methods: comparison of forecast postfire sediment loads estimated with prefire sediment-rating equations to measured postfire loads; and by postfire changes in suspended sediment load expressed per unit volume runoff. Both methods indicated postfire sediment increases that varied according to season. The higher elevation Lamar River basin had little postfire increase in spring snowmelt season sediment but large increases in summer sediment load. The Yellowstone River had postfire increases in sediment load for the spring but did not reflect the large summer increases of its upstream tributary. The reasons for the difference in postfire snowmelt sediment response are unclear but may relate to basin elevation differences, the effects of unburned watersheds, and cooler postfire springs. The few high streamflow snowmelt events in the postfire period mitigated postfire sediment increases.

Notes: During 1994 a project was initiated by Ordnance Survey to investigate the requirement for completing the multi-million pound digital revision of 1:2500 scale mapping within Great Britain. This paper, although concentrating on this scale of mapping, discusses the revision policy issues that faced Ordnance Survey and the practical implications arising from implementing the policy for its 1:2500 and 1:10 000 basic scale mapping. Use of contractors was seen as a prime requirement as the resources available within Ordnance Survey were not sufficient to implement the full revision programme. This paper discusses the background to the task and considers the range of photogrammetric options and contractual and quality procedures required for the revision of the mapping over the next few years.

Notes: Members of the Institute of Engineering Surveying and Space Geodesy, University of Nottingham have been working on a collaborative project with staff of the British Geological Survey and the National Remote Sensing Centre Air Photo Group. During this project, experience of using the Intergraph ImageStation and ERDAS Imagine has been obtained. This paper presents some of these experiences which highlight the merits and limitations of digital photogrammetry at this present time. These are important issues not only for photogrammetrists but also for those coming into contact with photogrammetric operations through their potentially increasing availability in general image processing software. Although based on the authors' experiences, the paper also intends to provide a summary of digital photogrammetric systems and therefore issues are presented in a general way.

Notes: The paper entitled The Photogrammetric Society Analogue Instrument Project was published in The Photogrammetric Record, 14(82): 565-582 (October 1993) and contained, as Appendix A, an extract from the Archive concerned with the history of the Zeiss Stereoplanigraph in Great Britain. Further extracts have appeared in each of the subsequent issues, the last two being concerned with the range of mechanical projection instruments produced by the Wild company. This extract, the seventh of the series, completes the history of the use of this type of instrument in the UK by giving some details of the instruments produced by other manufacturers.The Wild instruments always employed straight space rods rotating in space about cardan joints. Perhaps in consequence their designs were sometimes described as obvious or unimaginative but they were undoubtedly most successful in practice. In contrast, most of the designs dealt with in this extract could never attract such adjectives. All of them incorporate novel features of design and one or two of them are so unusual in their approach that the short technical descriptions provided here cannot hope to explain adequately the working principles of their design. As an innovative designer of mechanical projection plotting instruments, Ermenegildo Santoni can rightly be singled out as a person who made an outstanding contribution in this field but, as the following paragraphs show, he was not alone in showing a remarkably inventive flair in devising solutions to the problems of rectification and restitution by mechanical methods.

Notes: derivation of spatial data from European Remote Sensing Satellite (ERS-1) Synthetic Aperture Radar (SAR) imagery is briefly described in this paper. A rigorous algorithm for space intersection applied in different geometric configurations and combinations, including the “same-side” image pair and the “opposite-side” pair, is illustrated. A simple error model is proposed by the authors to validate the error from different radargrammetric configurations. The experimental results show the possibilities and the limitations of obtaining three dimensional information from spaceborne SAR imagery with or without using ground control points. At the present stage, as a supplementary role in space cartography, the ERS-1 SAR imagery not only provides a new way to see the earth through clouds but also makes available an alternative tool to map the planet.

Notes: A system capable of automatically deriving the three dimensional co-ordinates of well defined binarized targets is described. Significantly, the system comprises cheap “off the shelf” hardware and software, requiring a minimum of development. Comparative tests using imagery obtained with a Hasselblad semi-metric camera and a 35 mm SLR camera are presented. By means of automated sub-pixel measurement, the results achieved are equivalent to those undertaken through manual target measurement using a first order analytical plotter.

Notes: This paper discusses the work carried out to obtain stereoscopic “photography” from airborne platforms with a Kodak DCS200 digital camera, as part of an investigation into the suitability of current digital camera technology for use in air survey. Details of the work, from the initial test flight in a Cessna light aircraft through to tests utilizing a Thruster microlight platform, are documented. The paper concludes with a summary of the present shortcomings in obtaining aerial photography for survey purposes with still video technology and discusses the future prospects.

Notes: This paper describes how to calculate all the essential matrices corresponding to five matched point pairs. Statistics are presented from tests with synthetic data and an example is given which has six solutions. A linear method for six point pairs is also described; the resultant essential matrix is uniquely determined by the six point pairs because the method is linear. The author also reviews some results, that have applications to photogrammetry, from other researchers in this field.

Notes: Unique place-names are essential for scientific fieldwork in Antarctica. This shorter contribution describes how duplication of place-names in British Antarctic Territory has been avoided by the systematic naming of geographically related features according to groups of associated ideas. One such theme, commemorating pioneers in the development of photogrammetry, recognizes the important contribution of photogrammetry to Antarctic mapping and research.

Notes: Books reviewed:K. B. Atkinson, Close Range Photogrammetry And Machine VisionR. A. Earnshaw and D. Watson, Animation And Scientific Visualization—Tools And ApplicationsR. A. Earnshaw, M. A. Gigante and H. Jones, Virtual Reality SystemsS. Macdonald, Mapping The WorldP. Fisher, Innovations in GIS 2A. Gruen, O. Kuebler and P. Agouris, Automatic Extraction of Man-Made Objects From Aerial and Space ImagesH. Campbell and I. Masser, GIS and OrganisationsS. C. Guptill and J. L. Morrison, Elements of Spatial Data QualityD. Shirvanian, European Space Directory, 1996D. R. Green, D.Rix and C. Corbin, The Agi Source Book for Geographic Information Systems, 1996K. C. Graf, Realistic Landscape Rendering Using Remote Sensing Images, Digital Terrain Models and 3D Objects

Notes: After giving an account of his personal experiences in the mapping industry, the author considers definitions of the terms photogrammetry, GIS and multimedia. The interaction of photogrammetry and GIS from the viewpoint of commercial suppliers is examined with reference to four companies: Intergraph, Leica, Laser-Scan and ERDAS. The main effects on the end user of a fast developing market are identified as the need to choose from an ever increasing diversity of products and services, and the opportunity to benefit from the changing presentation of height information. Finally the subject of professional institutions is discussed; any proposals for further fragmentation should be resisted.

Notes: Communication between the photogrammetrist and the land surveyor is essential for the overall success of a large scale mapping project, but each will have individual responsibility for specific stages of the project. Liaison is also required to achieve the maximum accuracy for heighting. Other interface areas between photogrammetry and surveying include the use of scanned images, airborne GPS and the development of the GIS market. The author emphasizes that co-operation will be vital for 21st century mapping, not only between technical disciplines, but also between the commercial, government and academic sectors of the mapping industry.

Notes: Based on his personal experiences with preparing specifications, the author defines the objective of a specification and lists particular problems that may arise when confusion of purpose exists. Guidelines for drawing up a specification are then presented. Finally it is emphasized that communication between provider and client is the most essential factor in achieving a successful specification.

Notes: Prediction of the future is implicit in most management decisions. This paper examines how far it is necessary to make this prediction explicit in deciding management strategy, what technical changes are likely to affect survey and photogrammetry in the near and medium term future, and the balance between the disciplines. The question is posed as to what extent management should invest effort and money in attempting to stay ahead of the game.

Notes: A standard digitizing tablet was used to measure objects off cropped enlargements (1:1000 scale), with an absolute accuracy of 0.75 m. Interior orientation for the enlargements was based upon camera reference marks captured from the original photographs, ranging from 1:6000 to 1:15 000 scale. Control for exterior orientation was provided by 1:1000 scale maps. Operational procedures are outlined, followed by results from eight sample photographs. Particular attention is devoted to errors that influence measurement accuracy.

Notes: The features and applications of the low cost analytical plotters manufactured by ADAM Technology are described. The ADAM Technology products (the small format MPS-2 analytical stereoplotter, analytical conversions for Kern PG2 and Wild B8 analogue stereoplotter and the 230mm format Promap modular system) are discussed.

Notes: This paper examines the rationale behind the design and development of the CP 2 analytical plotter and shows how the final product, in terms of both hardware and software, has been influenced by the needs of a commercial air survey company.

Notes: The history of survey and map production methods used by the Ordnance Survey of the Republic of Ireland is outlined and the significance of the decision, taken in the 1960s, to maximize the use of computer technology is emphasized. The four objectives of the Ordnance Survey's current programme of work (urban mapping, small scale database, large scale database and private sector support) require effort to be concentrated on resurvey procedures and no revision of old mapping is carried out. Details are given of equipment possessed by the Ordnance Survey and of staff distribution, followed by descriptions of procedures adopted for achieving both the small scale and large scale databases. Justification is presented for the decision to commit major financial investment to digital photogrammetry.

Notes: The recently released Nikon E2 still video camera incorporates reduction optics technology which enables a full conventional 35mm image to be recorded on a 2/3 inch (17mm) CCD array. This paper investigates the metric impact of reduction optics through application of the technique of multisensor system self-calibration. The influence of the JPEG image compression facility contained within the E2 is also assessed in an overall evaluation of the camera for vision metrology applications which demand relatively high object point triangulation accuracies.

Notes: Ramsberg Castle is to be restored and renovated to allow a new use of the building. This requires extensive structural and architectural analyses based upon metric documentation. The façades of the castle were recorded photogrammetrically. Photography from the ground was impossible due to the steep terrain on three sides of the building. For this reason, the photographs were taken from a helicopter. A 4 × 5 inch Linh of Metrika réseau camera was used.Because of the adverse topography, only a few control points could be determined by on-site theodolite measurement. Therefore the control network was achieved by means of photogrammetric bundle triangulation. Stereorestitution was performed using an analytical plotter connected with a CAD system. Drawings at 1:50 scale were then derived from the as-built CAD model.

Notes: The paper entitled The Photogrammetric Society Analogue Instrument Project was published in The Photogrammetric Record, 14(82): 565-582 and contained, as Appendix A, an extract from the Archive concerned with the history of the Zeiss Stereoplanigraph in Great Britain. Further extracts have appeared in each of the subsequent issues.This extract, the sixth of the series, completes the history of the use of the various types of Wild instrument in the United Kingdom. It is concerned with the later post-war instruments, in numerical order, from the A7 Autograph to the A10 and therefore includes a note on one of the most popular and successful analogue plotting instruments ever produced, the Wild A8 Stereoplotter.At the moment, none of the instruments dealt with in this extract appear to be under immediate threat. However, their role as production instruments is fading fast in most organizations but they are being retained, often for training purposes.The Archive contains no mention of the last and most refined range of analogue instruments produced by Wild as their Aviomap (AM) series. With the benefit of hindsight it is now obvious that, at the time of their introduction, the transition from analogue to analytical techniques was about to take place at an accelerating pace. There is therefore no entry in the Archive for any AM or AM-U instrument; none (or perhaps only a very few) seem to have been imported into the United Kingdom.

Notes: This paper describes a project, the aim of which was to develop a computer assisted package for the teaching of analytical photogrammetry and especially the use of the ADAM Technology MPS-2 Micro Photogrammetric Stereoplotter.

Notes: A few of the many interesting aspects of the mind, life and work of Robert Hooke (1635-1703) are discussed, particularly some that are relevant to opto-mechanical photogrammetric plotters and cameras. Evidence from primary and secondary sources is presented which indicates that Hooke devised instruments with optical and mechanical components which later came to be used in photogrammetric plotters, that he recognized the value of perspective projection in accurate recording of terrain, and devised a “Picture-Box” for that purpose. The question of how far he progressed in photography in experiments with purple dyes is left open. These “photogrammetric” activities of Hooke's are shown to have been only a small part of his work in London which included duties as Curator of Experiments to the Royal Society, Professor of Geometry at Gresham College, and Surveyor to the City of London Authorities following the Great Fire in 1666.

Notes: Books Reviewed:S. F. El-Hakim, Videometrics IIJ. Denègre, Thematic Mapping From Satellite Imagery, A GuidebookT. C. Waugh and R. G. Healey, Advances In GIS ResearchJ. C. Muller, J.-P. Lagrange and R. WeibeGIS and Generalization. Methodology And PracticeP. M. Mather, Terra 2: Understanding the Terrestrial Environment. Remote Sensing Data Systems And NetworksB. Hofmann-Wellenhof, H. Lichtenegger and J. Collins, Global Positioning System: Theory and PracticeD. Shirvanian, European Space Directory 1995E. Falkner, Aerial Mapping: Methods And ApplicationsS. O. Mason, Expert System-Based Design of Photogrammetric NetworksS. F. El-Hakim, Videometrics IIID. Green and D. Rix, The Agi Source Book For Geographic Information Systems, 1995

Notes: : The implications of fitting distributions with non-zero lower limits to low flow data are examined. The 3-parameter Weibull distribution is fitted to annual minimum flow series from 60 long term stations in Canada. The relations between the estimated lower limit and three sampling variables (skewness, smallest, and largest observations) were investigated. The lower limit strongly depends on the sample skewness; it varies directly with the sample skewness, which in turn is highly influenced by the largest observation. For a given skewness, the value of the estimated lower limit is determined by the value of the smallest observation. Therefore, the lower limit cannot be accurately determined, and the resulting low flow estimates will be either too small or too high.

Notes: : One of the principal stumbling blocks to regulatory agencies' adopting pollutant trading schemes is the complex of uncertainties surrounding any change in institutions. This is especially true if nonpoint pollution sources are to be involved along with point sources. Regulators are understandably reluctant to switch from tried-and-true point source permit systems, even if trading schemes can be shown (on paper, at least) to result in lower public expenditures. We propose a set of practical criteria for point-nonpoint pollutant trading systems that promise to increase regulators' confidence that the new system will be equally effective in controlling pollution and at the same time more likely to capture efficiencies in pollution reduction practices.

Notes: : The ability to predict how streams and wetlands retain phosphorus (P) is critical to the management of watersheds that contribute nutrients to adjacent aquatic systems such as lakes. Field and laboratory experiments were conducted to determine the P assimilatory capacity of a stream (Otter Creek) in the Taylor Creek/Nubbin Slough Basin located north of Lake Okeechobee, Florida. Dominant soils in this basin are sandy Spodosols; landuse is primarily dairy farms and beef cattle pastures. Estimates of P assimilation show that sediments assimilate approximately 5 percent of the P load. Phosphorus assimilation rates in the stream were estimated using first-order relationships based on the total P concentration of the water column as a function of distance from the primary source. This method assumes minimal lateral inputs. Stream lengths required for one turnover in P assimilation were estimated to be in the range of 3–16 km. Laboratory studies using intact sediment cores indicated a P assimilation rate of 0.025 m day−1, and equilibrium P concentration of 0.16 ± 0.03 mg L−1 in the water column. Dissolved P concentration gradients in the sediments showed upward flux of P at water column P concentration of 〈0.16 mg L−1. Approximately 56–77 percent of the P assimilated in the above-ground vegetation during active growth was released or translocated within six months of senesence, suggesting short-term storage in above-ground vegetation. Bottom sediments and recalcitrant detrital plant tissue provide for long-term P assimilation in the creek. Although stream sediments have the potential to adsorb P, high flow rate and low contact period between water and sediment limits this process.

Notes: : Median concentrations and instantaneous yields of alachlor, metolachlor, atrazine, cyanazine, and simazine were generally highest at sites in the Lower Susquehanna River Basin and in agricultural subbasins. Instantaneous herbicide yields are related to land use, hydrogeologic setting, streamflow yield, and agricultural row cropping practices. The significance of these relations may be affected by the interdependence of the factors. The percentage of basin area planted in corn is the most influential factor in the prediction of herbicide yield. Instantaneous yields of all five herbicides measured in June 1994 related poorly to averaged 1990–94 herbicide use. Annually averaged herbicide-use data are too general to use as a predictor for short-term herbicide yields. An evaluation of factors affecting herbicide yields could be refined with more-current land use and land cover information and a more accurate estimate of the percentage of basin area planted in corn. Factors related to herbicide yields can be used to predict herbicide yields in other basins within the Chesapeake Bay watershed and to develop an estimate of herbicide loads to Chesapeake Bay.

Notes: : Algal blooms, defined as chlorophyll α concentrations greater than 40 μg l−1, are common in Lake Okeechobee, Florida. Using logistic regression techniques, we have developed equations that relate limnological variables to algal bloom occurrence in four distinct open-water regions of this large shallow lake: central pelagic, northwest, southwest, and a transition region between the western and pelagic regions. Wind velocity and total phosphorus, which are closely related to resuspended material in the central region, are negatively related to algal bloom occurrence there. In the transition region, algal bloom occurrence is positively related to total nitrogen and wind velocity. Algal bloom occurrence is strongly and positively related to total nitrogen and total phosphorus concentrations in the western regions. The logistic regression model predicts an algal bloom probability greater than 95 percent in the northwest region when total phosphorus exceeds 0.10 mg l−1 and total nitrogen exceeds 2.5 mg l−1. In the southwest region the model predicts algal bloom probability of 100 percent when total phosphorus exceeds 0.10 mg l−1 and total nitrogen exceeds 2.8 mg l−1. Given 1994 mean total phosphorus concentrations of 0.05 and 0.04 mg l−1 in the northwest and southwest regions, respectively, total nitrogen would have to remain below 1.32 and 1.43 mg l−1, respectively, to keep the algal bloom probability below 10 percent. Because the lake is heterogenous, such nutrient standards should be considered on an in-lake regional basis for Lake Okeechobee.

Notes: : We present an ecological risk assessment methodology at the watershed level for freshwater ecosystems. The major component is a pollutant transport and fate model (a modified EUTROMOD) with an integrated uncertainty analysis utilizing a two-phase Monte Carlo procedure. The uncertainty analysis methodology distinguishes between knowledge uncertainty and stochastic variability. The model assesses the ecological risk of lentic (lake) ecosystems in response to the stress of excess phosphorus resulting in eutrophication. The methodology and model were tested on the Wister Lake watershed in Oklahoma with the lake and its trophic state as the endpoint for ecological risk assessment. A geographic information system was used to store, manage, and manipulate spatially referenced data for model input.

Notes: : Snowmelt from deep mountainous snowpacks is seldom rapid enough to exceed infiltration rates; thus, the source of streamflow in many mountainous watersheds is snowmelt recharge through shallow ground water systems. The hydrologic response and interaction between surface and sub-surface flow processes in these watersheds, which is controlled by basin structure, the spatial distribution of snowmelt, and the hydrogeology of the subsurface, are not well understood. The purpose of this study was to test a three-dimensional ground water model using simulated snowmelt input to simulate ground water response to spatially distributed snowmelt on the Upper Sheep Creek Watershed located within the Reynolds Creek Experimental Watershed in Southwestern Idaho. The model was used to characterize the mountainous aquifer and to delineate the subsurface flow mechanisms. Difficulty in finding a reasonable combination of grid spacing and time stepping within the model was encountered due to convergence problems with the Picard solution to the non-linear variably saturated ground water flow equations. Simulation results indicated that flow may be either unconfined or confined depending on inflow rate and hydrogeologic conditions in the watershed. The flow mechanism had a much faster response time when confined flow occurred. Response to snowmelt from a snow drift approximately 90 m away took only a few hours when flow was confined. Simulated results showed good agreement with piezometer measurements both in magnitude and timing; however, convergence problems with the Picard solution limited applicability of the model.

Notes: : A methodology has been developed to predict the responses of a range of water supply sources in Wales to global warming scenarios. Hydrologically effective rainfall is predicted from temperature and precipitation for each season based on site specific formulae developed using the Meteorological Office Rainfall and Evaporation Calculation System (MORECS) and UK Surface Water Archive databases. Comparisons are then made between the effects predicted for the scenarios established from equilibrium simulations and the new Hadley Centre High Resolution Model (UKHI) transient mode results. Though very different, both suggest increased stress on water resources late in the hydrological year.

Notes: : Rainfall data products generated with the national network of WSR-88D radars are an important new data source provided by the National Weather Service. Radar-based data include rainfall depth on an hourly basis for grid cells that are nominally 4 km square. The availability of such data enables application of improved techniques for rainfall-runoff simulation. A simple quasi-distributed approach that applies a linear runoff transform to grid-ded rainfall excess has been developed. The approach is an adaptation of the Clark conceptual runoff model, which employs translation and linear storage. Data development for, and results of, an initial application to a 4160 km2 watershed in the Midwestern U.S. are illustrated.

Notes: : Streamflow for 67 years was simulated for Coon Creek at Coon Valley, Wisconsin, for three conditions in the drainage basin: (1) conditions in the 1930s; (2) conditions in the 1970s, excluding flood-detention reservoirs; and (3) conditions in the 1970s, including flood-detention reservoirs. These simulations showed that the changes in agricultural practices over 40 years (1940–80) reduced the 100-year flood by 53 percent (from 38,900 to 18,300 cubic feet per second). The flood-detention reservoirs reduced the 100-year flood by an additional 17 percent (to 15,100 cubic feet per second). The simulation was accomplished by calibrating a precipitation-runoff model to observed rainfall and runoff during two separate periods (1934–40 and 1978–81). Comparisons of model simulations showed that differences between the model calibrations for the two periods were statistically significant at the 95 percent confidence level.

Notes: : A new insoluble N-halamine polymeric disinfectant material has been tested in a water filter application to determine (1) its tendencies to leach undesirable decomposition products, (2) its range of potential applicability, and (3) its regenerability. In flowing water tests, poly-1,3-dichloro-5-methyl-5-(4‘-vinylphenyl)hydantoin (Poly-I) leached only small amounts of total organic carbon, free and total chlorine, anions, and volatile organics such as trihalomethanes. Furthermore, Poly-I provided bactericidal efficacy over the pH range 4.5 to 9.5 and at temperatures as high as 37°C. Poly-I is deactivated by reducing agents such as sodium thiosulfate and by ethanol; following deactivation, it can be regenerated by exposure to flowing aqueous free chlorine. Poly-I appears suitable for use as a biocidal filter for small potable and recreational waters, for it is effective over a wide pH and temperature range and is readily regenerable. It would not be useful, however, for disinfection of large bodies of water such as in city treatment plants because of its cost and the large amount of the material that would be necessary.

Notes: : The Buffalo River is a tributary to the Mississippi River in west-central Wisconsin that drains a watershed dominated by agricultural land uses. Since 1935, backwater from Lock and Dam 4 on the Mississippi River has inundated the mouth of the Buffalo's valley. Resurveys of a transect first surveyed across the lake in 1935 and cesium-137 dating of backwater sediments reveal that sedimentation rates at the Buffalo's mouth have remained unchanged since the mid-1940s. Study results indicate that sediment yields from the watershed have persisted at relatively high levels over a period of several decades despite pronounced trends toward less cultivated land and major efforts to control soil erosion from agricultural land. The maintenance of sediment yields is probably due to increased channel conveyance capacities resulting from incision along some tributary streams since the early 1950s. Post-1950 incision extended the network of historical incised tributary channels, enhancing the efficient delivery of sediment from upland sources to downstream sites.

Notes: : A variety of management options are used to minimize losses of nitrogen (N), phosphorus (P), and other potential pollutants from agricultural source areas. There is little information available, however, to indicate the effectiveness of these options (sometimes referred to as Best Management Practices, or BMPs) on basin scales. The objective of this study was to assess the water quality effectiveness of BMPs implemented in the 3240 ha Lincoln Lake basin in Northwest Arkansas. Land use in the basin was primarily forest (34 percent) and pasture (56 percent), with much of the pasture being regularly treated with animal manures. The BMPs were oriented toward minimizing the impact of confined animal operations in the basin and included nutrient management, dead bird composter construction, and other practices. Stream flow samples (representing primarily base flow conditions) were collected bi-weekly from five sites within the basin from September 1991 through April 1994 and analyzed for nitrate N (NO3-N), ammonia N (NH3-N), total Kjeldahl N (TKN), ortho-P (PO4-P), total P (TP), chemical oxygen demand (COD), and total suspended solids (TSS). Mean concentrations of PO4-P, TP, and TSS were highest for subbasins with the highest proportions of pasture land use. Concentrations of NH3-N, TKN, and COD decreased significantly with time (35–75 percent/year) for all sub-basins, while concentrations of other parameters were generally stable. The declines in analysis parameter concentrations are attributed to the implementation of BMPs in the basin since (a) the results are consistent with what would be expected for the particular BMPs implemented and (b) no other known activities in the basin would have caused the declines in analysis parameter concentrations.

Notes: : A method for quantifying fluctuations in time-series data was developed and tested to aid the process of visualization. The methodology is based on free-form sliding polynomials and identifies (a) short-period variability about the mean value, (b) a long-term trend or cycle, and (c) random errors residual to these two structured components. Consistent results were obtained for designed synthetic data and natural data from seven sites in Georgia. Statistics of fit of the analytical model for the natural data were not significant on a site-by-site basis. An unexpected finding for the study was obtained when the statistical results for the seven data sets for temperature were pooled. The smoothing model yielded consistent long-term trends even though the individual station results were not significant. Also, the correlation coefficients, while low, showed a statistically significant trend toward higher values toward the northwest and away from the Georgia coast line. This study thus supports the concept that multiple-site, and regionally based, analyses are necessary for the detection of trends. Secondarily, such consistency of results strengthens the conclusion that the proposed smoothing method is an effective procedure in the presence of varying amounts of random content in the natural data sets.

Notes: : SWMHMS is a conceptual computer modeling program developed to simulate monthly runoff from a small nonurban watershed. The input needed to run model simulations include daily precipitation, monthly data for evapotranspiration determination (average temperature, crop consumptive coefficients, and percent daylight hours), and six watershed parameter values. Evapotranspiration was calculated with the Blaney-Criddle equation while surface runoff was determined using the Soil Conservation Service curve number procedure. For watershed parameter evaluation, SWMHMS provides options for both optimization and sensitivity analysis. Observed runoff data are required along with the model input previously mentioned in order to conduct parameter optimization. SWMEIMS was tested with data from six watersheds located in different regions of the United States. Model accuracy was generally found to be very good except on watersheds having substantial snowfall accumulation.In having only six watershed parameters, SWMHMS is less complex to use than many other computer programs that calculate monthly runoff. Consequently, SWMHMS may find its greatest application as an educational tool for students learning principles of hydrologic modeling, such as parameter evaluation procedures and the impacts of input data uncertainty on model results.

Notes: : The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian Region. Karst areas comprise about 18 percent of the Region's land area. An estimated one-third of the Region's farms, cattle, and agricultural market value are on karst terrain. Nitrate concentrations were measured in cave streams draining two primary land management areas. The first area was pasture serving a beef cow-calf operation. The second area was a dairy. Nitrate-N concentrations were highest in cave streams draining the dairy and a cave stream draining an area of pasture where cattle congregate for shade and water. The dairy contributed about 60 to 70 percent of the nitrogen load increase in the study section of the cave system. It was concluded that agriculture was significantly affecting nitrate concentrations in the karst aquifer. Best management practices may be one way to protect the ground water resource.

Notes: : We compared the recovery from abusive grazing of aquatic habitat due to different range management on two geomorphically similar rangeland streams in northwest Nevada. Managers excluded livestock from the Mahogany Creek watershed from 1976 to 1990 while allowing rotation of rest grazing on its tributary Summer Camp Creek. Bank stability, defined as the lack of apparent bank erosion or deposition, improved through the study period on both streams, but periodic grazing and flooding decreased stability more on Summer Camp Creek than flooding alone on Mahogany Creek. Pool quantity and quality on each stream decreased because of coarse woody debris removal and sediment deposition during a drought. Fine stream bottom sediments decreased five years after the removal of livestock, but sedimentation increased during low flows in both streams below road crossings. Tree cover increased 35 percent at both streams. Thus, recovery of stability and cover and decreased sedimentation are compatible with rotation of rest grazing on Summer Camp Creek. Width/depth ratio and gravel/cobble percent did not change because they are inherently stable in this stream type. Management activities such as coarse woody debris removal limited pool recover and road crossings increased sedimentation.

Notes: : Detailed studies of long-term management impacts on rangeland streams are few because of the cost of obtaining detailed data replicated in time. This study uses government agency aquatic habitat, stream morphologic, and ocular stability data to assess land management impacts over four years on three stream reaches of an important rangeland watershed in northwestern Nevada. Aquatic habitat improved as riparian vegetation reestablished itself with decreased and better controlled livestock grazing. However, sediment from livestock disturbances and road crossings and very low stream flows limited the rate of change. Stream type limited the change of pool variables and width/depth ratio, which are linked to gradient and entrenchment. Coarse woody debris removal due to previous management limited pool recovery. Various critical-element ocular stability estimates represented changes with time and differences among reaches very well. Ocular stability variables tracked the quantitative habitat and morphologic variables well enough to recommend that ocular surveys be used to monitor changes with time between more intensive aquatic surveys.

Notes: : The need to monitor and forecast water resources accurately, particularly in the western United States, is becoming increasingly critical as the demand for water continues to escalate. Consequently, the National Weather Service (NWS) has developed a geostatistical model that is used to obtain areal estimates of snow water equivalent (the thtal water content in all phases of the snowpack), a major source of water in the West. The areal snow water equivalent estimates are used to update the hydrologic simulation models maintained by the NWS and designed to produce extended streamflow forecasts for river systems throughout the United States. An alternative geostatistical technique has been proposed to estimate snow water equivalent. In this research, we describe the two methodologies and compare the accuracy of the estimates produced by each technique. We illustrate their application and compare their estimation accuracy using snow data collected in the North Fork Clearwater River basin in Idaho.

Notes: : This paper uses the fundamental values of decision makers to guide a long-term wastewater planning process at Seattle Metro, a major utility district. Multiattribute value assessment is used to elicit the objectives of several elected officials and other key decision makers. The results are structured into a fundamental objectives hierarchy and a means-ends objectives network. A set of measures to indicate the performance of planning alternatives in terms of the fundamental objectives is developed. Preliminary value tradeoffs between objectives are elicited from several elected officials. The results of these steps are useful for many aspects of long-term planning: facilitating communication about values and priorities; designing attractive alternatives that are more likely to serve stakeholder interests; identifying information needed to evaluate alternatives; clarifying the relative importance of information about different impacts; providing a basis for quantitative evaluation of the alternatives with multiple objective analysis; and focusing attention on key tradeoffs that will affect the choice of alternatives.

Notes: : Low-flow estimates, as determined by probabilistic modeling of observed data sequences, are commonly used to describe certain streamflow characteristics. Unfortunately, however, reliable low-flow estimates can be difficult to come by, particularly for gaging sites with short record lengths. The shortness of records leads to uncertainties not only in the selection of a distribution for modeling purposes but also in the estimates of the parameters of a chosen model. In flood frequency analysis, the common approach to mitigation of some of these problems is through the regionalization of frequency behavior. The same general approach is applied here to the case of low-flow estimation, with the general intent of not only improving low-flow estimates but also illustrating the gains that might be attained in so doing. Data used for this study is that which has been systematically observed at 128 streamflow gaging sites across the State of Alabama. Our conclusions are that the log Pearson Type 3 distribution is a suitable candidate for modeling of Alabama low-flows, and that the shape parameter of that distribution can be estimated on a regional basis. Low-flow estimates based on the regional estimator are compared with estimates based on the use of only at-site estimation techniques.

Notes: : Precipitation, streamflow, and population data were analyzed over the 1941–1990 period to determine whether changes in stormflows and net (post. minus pre-rainstorm) stormflows, associated with warm-season large rainstorms, were similar for two urbanized northeastern Illinois basins. Warm season large rainstorms were defined as April through October rainfall events in which ≪ 5.1 cm occurred in a 48-hour period over the basin. To minimize differences associated with varying large rainstorm amounts over time, the net sthrmflow for each event was divided by the large rainstorm amount. This ratio, Ui, indicated that the two urbanized basins experienced significant, yet different, increases (102 percent and 49 percent) in flow amount per centimeter of rainfall from 1941–1965 to 1966–1990. Results of a regression analysis between Ui and population showed that the increase in Ui per 100,000 increase in population ranged from 0.59 to 0.67 m3s-1 per cm of rainfall for the two basins. These results demonstrate the varying degree of change that urban planners can expect in stormflows associated with large warm season rainstorms for areas undergoing urbanization.

Notes: : Geographic Information Systems (GIS) are being used increasingly as a method of preparing, analyzing, and displaying data for watershed analysis and modeling. Although GIS technology is a powerful tool for integrating and analyzing watershed characteristics, the initial preparation of the necessary database is often a time consuming and costly endeavor. This demonstration project assesses the viability of creating a cost-effective spatial database for urban stormwater modeling from existing digital and hard-copy data sources. The GIS was used to provide input parameters to the Source Loading and Management Model (SLANM), an empirical urban stormwater quality model. Land use characteristics, drainage boundaries, and soils information were geocoded and referenced to a base data layer consisting of transportation features. GIS overlay and data manipulation capabilities were utilized to preprocess the input data for the model. Model output was analyzed through postprocessing by GIS, and results were compared to a similar recent modeling study of the same watershed. The project, undertaken for a small urban watershed located in Plymouth, Minnesota, successfully demonstrates that the use of GIS in stormwater management can allow even small communities to reap the benefits of stormwater quality modeling.

Notes: : Environmental decision making involving trace-levels of contaminants can be complicated by censoring, the practice of reporting concentrations either as less than the limit of detection (LOD) or as not detected (ND) when a test result is less than the LOD. Censoring can result in data series that are difficult to meaningfully summarize, graph, and analyze through traditional statistical methods. In spite of the relatively large measurement errors associated with test results below the LOD, simple and meaningful analyses can be carried out that provide valuable information not available if data are censored. For example, an indication of increasing levels of contamination at the fringe of a plume can act as an early warning signal to trigger further study, an increased sampling frequency, or a higher level of remediation at the source. This paper involves the application of nonparametric trend analyses to uncensored trace-level groundwater monitoring data collected between March 1991 and August 1994 on dissolved arsenic and chromium for seven wells at an industrial site in New York.

Notes: : This paper describes a concept for identification and ranking of outdoor recreation habitats using principles of ecology as a guide. The Habitat Evaluation Procedures (HEP) is a commonly used technique for assessment of human impacts on the vigor of wildlife species, and serves as the model for the Recreation Habitat Analysis Method (RHAM). Recreation activities are dependent on habitat attributes for their success just as are wildlife species. A sample model is described for recreation activities at large, multipurpose lakes. RHAM could be applied to recreation experiences in a variety of settings including smaller water bodies and riparian and terrestrial ecosystems.

Notes: : Base-flow samples were collected from 47 sampling sites for four seasons from 1990–91 on the Delmarva Peninsula in Delaware and Maryland to relate stream chemistry to a “hydrologic landscape” and season. Two hydrologic landscapes were determined: (1) a well-drained landscape, characterized by a combination of a low percentage of forest cover, a low percentage of poorly drained soil, and elevated channel slope; and (2) poorly drained landscape, characterized by a combination of an elevated percentage of forest cover, an elevated percentage of poorly drained soil, and low channel slope. Concentrations of nitrogen were significantly related to the hydrologic landscape. Nitrogen concentrations tended to be higher in well-drained landscapes than in poorly drained ones. The highest instantaneous nitrogen yields occurred in well-drained landscapes during the winter. These yields were extrapolated over the part of the study area draining to Chesapeake Bay in order to provide a rough estimate of nitrogen load from base flow to the Bay and its estuarine tributaries. This estimate was compared to an estimate made by extrapolating from an existing long-term monitoring station. The load estimate from the stream survey data was 5 ± 106 kg of N per year, which was about four times the estimate, made from the existing long-term monitoring station. The stream-survey estimate of base flow represents about 40 percent of the total nitrogen load that enters the Bay and estuarine tributaries from all sources in the study area.

Notes: : This study was to designed to determine concentrations of selected metals, organic compounds, pesticides, and conventional pollutants in stormwater runoff from two North Carolina businesses in each of the following five general industrial groups: auto salvage, metal fabrication, scrap and recycling, vehicle maintenance, and wood preserving facilities. The sampling procedure involved collecting a first flush sample of runoff from a single storm event and both first flush and composite samples of runoff from three consecutive storm events. Analysis of samples collected during the first flush indicated that zinc and copper were the most common of the 13 metals included in the analysis. Additional analysis documented that several volatile organic, semi-volatile organic, or pesticide compounds including acrolein, methylene chloride, xylenes, toluene, tetrachloroethylene, trichloroethylene, pentachlorophenol, and aldrin were also found in the first flush samples. Concentrations of aggregate organics, nitrogen, phosphorus, and sediment were determined in both first flush and three-hour composite samples. Concentrations of pollutants in first flush samples were similar to those in corresponding composite samples.

Notes: : Atrazine and atrazine-residue (atrazine + two metabolites - deethylatrazine and deisopropylatrazine) concentrations were examined to determine if consideration of these atrazine metabolites substantially adds to our understanding of the distribution of this pesticide in groundwater of the midcontinental United States. The mean of atrazine.residue concentrations was 53 percent greater than that of atrazine alone for those observations above the detection limit (〉 0.05 μg/l). Furthermore, a censored regression analysis using atrazine-residue concentrations revealed significant factors not identified when only atrazine concentrations were used. Thus, knowledge of concentrations of these atrazine metabolites is required to obtain a true estimation of risk of using these aquifers as sources for drinking water, and such knowledge also provides information that ultimately may be important for future management policies designed to reduce atrazine concentrations in ground water.

Notes: : A non-linear optimization model is applied to the California State Water Project (SWP) and portions of the Central Valley Project (CVP). The model accounts for the major hydrologic, regulatory, and operational features of both projects. The model maximizes long-term SWP yields over a 70-year period, using a quarterly time step. The potential for increased yield associated with a proposed facility improvement is evaluated with the model. The proposed facility is an extension of the Folsom-South Canal, which would allow water to be conveyed from the American River below Folsom Reservoir into New Melones Reservoir on the Stanislaus River or into the California Aqueduct. Model results indicate that extension of the Folsom-South Canal has the potential to increase SWP yields by 13 percent.

Notes: : At the Everglades Nutrient Removal project in south Florida, three lysimeters were installed to measure daily evapotranspiration (ET) rates from cattails (Typha domingensis), mixed marsh vegetation, and an open water/algae system. The cattail lysimeter began operation in February 1993. The mixed marsh vegetation lysimeter began operation in January 1994, and the open water lysimeter with occasional algae cover began operation in December 1993. The mean measured ET rate was 3.6 mm, 3.5 mm, and 3.7 mm per day for the cattail, mixed marsh vegetation, and open water/algae system, respectively. High resolution weather data were continuously measured at the site. Six models were applied to estimate daily ET rates of the three systems. The Penman-Monteith equation best estimated ET of cattail and mixed marsh vegetation, and the Penman Combination equation was most suitable for the open water/algae system. Empirical equations based on solar radiation and maximum temperature produced estimates of daily ET from the three systems that are comparable to models that require many more parameters. In cases where limited data is available, the calibrated simple models can be used to estimate ET from wetlands in south Florida.

Notes: Personal exposure in a displacement ventilated room is examined. The stratified flow and the considerable concentration gradients necessitate an improvement of the widely used fully mixing compartmental approach. The exposure of a seated and a standing person in proportion to the stratification height is examined by means of full-scale measurements. A breathing thermal manikin is used to simulate a person. It is found that the flow in the boundary layer around a person is able to a great extent to entrain and transport air from below the breathing zone. In the case of non-passive, heated contaminant sources, this entrainment improves the indoor air quality. Measurements of exposure due to a passive contaminant source show a significant dependence on the flow field as well as on the contaminant source location. Poor system performance is found in the case of a passive contaminant released in the lower part of the room close to the occupant. A personal exposure model for displacement ventilated rooms is proposed. The model takes the influence of gradients and the human thermal boundary layer into account. Two new quantities describing the interaction between a person and the ventilation are defined.

Notes: Abstract Mechanical ventilation of workrooms was formerly based mainly on the dilution principle. In recent years, however, 50% of new investments in industrial ventilation in Scandinavia have been spent on displacement ventilation. Very little data exist from industrial settings on the relative performance of displacement ventilation versus dilution ventilation as regards air quality and thermal comfort. The present study collected data on the indoor climate in a sewing plant before and after the ventilation was changed from dilution to displacement. The indoor climate was evaluated by hygienic measurements of air pollution, temperature, air velocity, etc., and 40 employees were interviewed about perceived thermal comfort, air quality, and irritative symptoms.Changing the ventilation from dilution to displacement induced a slightly higher air change in the occupied zone of the plant and entailed higher temperature gradients. In spite of these findings, complaints of draught decreased significantly, and temperature was perceived to be more pleasant after the change. The air was perceived as less heavy and less dry, especially when humidification was added to the supply air. The improvements in the workers’ reports on the environment could not be attributed to placebo effects. Generally, the hygienic measurements were improved or unchanged after the change in ventilation system. Thus, displacement ventilation improved environmental conditions in this study. When adding humidification, this improvement was further sustained.

Notes: Abstract A simple method for quantifying dust on indoor non-textile surfaces has been developed and evaluated. The method uses gelatine foils to sample particles from surfaces, applying a constant pressure. The foils possess unique properties, making them particularly suitable for evaluation by light extinction. The amount of particles collected as measured by laser light extinction is expressed as the area percentage covered by particles. Foil sampling effectiveness has been estimated to range from 87% to 97%. A simple method for calibrating the instrument has been developed. The relation between the total projected particle area excluding overlap can be determined from the measured projected area including overlap from a simple equation. An overall uncertainty is given, including effects of positioning foils in the detector, sampling from rough surfaces, and the natural variability due to the discrete nature of particles. The lower level of detection for dust on an object is less than 0.5% surface area covered by dust. The method has formed the basis for suggesting a sampling strategy and surface dust limits in relation to cleaning and the quality of the indoor environment.

Notes: Abstract Adjustment of ventilation rates in buildings is widely practised, both to provide good air quality on a proactive basis and to mitigate air quality problems associated with occupant complaints. However, both cross-sectional and experimental epidemiological studies have reported mixed results and have for the most part failed to establish definitive relationships between ventilation rates and symptom prevalence or dissatisfaction with air quality. The difficulties involved in establishing such relationships may be due to a variety of confounding factors which include limitations in study design and interaction effects; difficulties in controlling ventilation rates in experimental studies; inadequate mixing of supply air in occupied spaces; high source strengths for some contaminants; dynamic interactions between sources and ventilation rates that result in increased contaminant emissions; contaminant dose-response sensory effects which are log-linear; potential contaminant generation within ventilation systems themselves; and multifactorial genesis of sick building symptoms.There is limited evidence to suggest that ventilation rate increases up to 10 L/s person may be effective in reducing symptom prevalence and occupant dissatisfaction with air quality and that higher ventilation rates are not effective. Because of complex relationships between ventilation rates, contaminant levels, and building-related health complaints/dissatisfaction with air quality, the use of ventilation as a mitigation measure for air quality problems should be tempered with an understanding of factors which may limit its effectiveness.

Notes: Abstract Humidifiers, used in approximately 25% of Canadian homes, may potentially aggravate asthma by increasing the airborne concentrations of fine particles and microbials. A randomized controlled study was carried out to investigate the acute effects of humidifier use on asthma control. Daily peak flows, asthma symptoms and need for medication were assessed during 2 weeks (period 1) when 110 subjects were using humidifiers and during the following 3 weeks (period 2) when half of the subjects were randomized to stopping the humidifier and the other half to continuing its use. In the intervention group, mean morning peak flows were 357 L/min (SEM 17) during humidifier use (period 1) and 352 L/min (SEM 16) when humidifiers were not used, a difference of - 4.4 L/min (95%CI - 11.2 to 2.3) (period 2). Respective values in the control group were 403 L/min (SEM 16) during period 1 and 405 L/min (SEM 16) during period 2. No significant differences were found when analyses were restricted to portable humidifiers, allergies to mites and/or molds, and infrequently cleaned humidifiers. Humidifiers cause no short-term adverse health effects in the majority of those with asthma. Future studies should address the broader question concerning the chronic effects of increased home humidity on microflora and health.

Notes: Abstract A study was undertaken to investigate the use of mass balance modeling techniques to predict air pollution concentrations in residential settings where the source is evaporative emissions of alternative fuels emitted in the attached garage. Field study measurements of the spatial and temporal distribution of evaporative emissions in an attached garage were used to conduct this investigation. In this field study, known quantities of methanol were allowed to evaporate in the garage. Methanol concentrations were then measured and simulated in the garage. Because chemical and physical properties of this contaminant are clearly understood, it was possible to simulate the concentrations inside the remainder of the house.A multi-zonal mass balance model (CONTAM88) was used to predict the across-residence spatial and temporal distribution of concentrations of evaporative emissions from a methanol source inside the attached garage. The model's input data include physical characteristics of the house; parameters characterizing the leakiness of the house; heat, ventilation and air-conditioning system characteristics; fixed airflow data from vent registers; on-site meteorological measurements; and information on the contaminant source.Before using the model to simulate methanol dispersions, the model's performance was tested. Sulfur hexafluoride (SF6) measurements were taken throughout the residence and garage. The model was used to predict interzonal airflow rates and SF6 concentration distributions within the garage and the house, as well as to investigate the well-mixed zone assumption for the garage. Modeling results show that predicted garage SF6 concentrations agreed reasonably well with the measured concentrations under mixed conditions, but the model underpredicted the SF6 concentrations within rooms of the house where mixing was probably incomplete. Methanol simulation results showed that the model underpredicted by approximately 15 percent the garage methanol concentration after methanol emissions stopped.This study found that evaporative emissions in an attached garage have a tendency to infiltrate the house, with rooms adjacent to the garage showing the highest levels of methanol concentrations. Thus automotive evaporative emissions may represent a source of indoor pollution and human exposure in a residential attached garage and also in other critical locations of the residence.

Notes: Abstract The objective of this study was to assess the magnitude and balance of mechanical ventilation in the rooms of Helsinki metropolitan office buildings with different types of ventilation systems. A random sample of 50 office buildings was selected from the Building Registry. Of these buildings, the 33 that have a mechanical ventilation system were included in this study. Most office buildings in the Helsinki metropolitan area have a ducted supply and exhaust system and hot water radiator heating. Air recirculation is used in about half of the buildings which have a mechanical supply and exhaust system. The average exhaust airflow was 1.2 L/s, m2 (SD 0.73) or 17.2 L/s per person (SD 11.6). The variation of the airflows was found to be very high among the buildings, and among the rooms within the buildings. Therefore, even though the ventilation rates on average comply with the Finnish building code, it was found that many people were working in offices with airflows which were either too low or unnecessarily high.

Notes: Abstract Analysis of the impact of sources on indoor pollutant concentrations and occupant exposure to indoor pollutants requires knowledge of the emission rates from the sources. Emission rates are often determined by chamber testing and the data from the chamber test are fitted to an empirical model. While the empirical models are useful, they do not provide information necessary to scale the chamber data to buildings nor do they provide information necessary to understand the processes controlling emissions. A mass transfer model for gas-phase-limited mass transfer is developed and described in this paper. Examples of sources with gas-phase-limited emissions are moth cakes, floor wax, stain, and varnish. The mass transfer model expresses the emission rate in terms of a mass transfer coefficient and a driving force. The mass transfer coefficient can be predicted from correlations of the Nusselt number and the Reynolds number. The experiments and data analysis used to develop the correlation are described in the paper. Experiments to verify the assumptions used to describe the driving force are also described. Suggestions for using data from existing empirical emission models to determine parameters for the mass transfer model are provided. The mass transfer model provides a significantly better fit to data from an indoor air quality test house than does the empirical first order decay model.

Notes: Abstract The literature for the control of dust mites by modification of the psychrometric conditions of the environment is reviewed from the standpoint of a building scientist or engineer, both to present to building science workers an envelope of micro-environment psychrometric conditions to use as control, and to highlight those areas of dust mite biology that require further research to complete the knowledge of the psychrometric envelope for dust mite viability. Some important data to allow tight specification of psychrometric control conditions are missing, viz.: the temperature dependence of critical equilibrium activity for Dermatophagoides pteronyssinus and Euroglyphus maynei; behaviour of dust mite populations under a fluctuating climate; and the difference between wild and laboratory populations. The widely quoted figure for dust mite control of 7 g/mg absolute humidity should be used with caution.

Notes: Abstract The sensory pollution load and microbial contamination of glass-fibre filters at high and low relative humidity were investigated in an experimental set-up in the laboratory. Dust and particles from the outdoor air were collected in two EU7 glass-fibre filters for a pre-conditioning period of 16–18 weeks during which there was a constant airflow with a velocity of 1.9 m/s through the filters. One of the filters was exposed to outdoor air of approximately 40% relative humidity and 10°C, the other to outdoor air of approximately 80% relative humidity and 5°C. The dust in ventilation filters can constitute a serious pollution source in the indoor environment, causing deterioration in the quality of the supply air even before it enters the ventilated spaces. The sensory pollution load from the used filters after the continuous operating time of 16–18 weeks was significantly higher than the sensory pollution load from new filters but the sensory load at 40% and 80% relative humidity did not differ. The microbial contamination of the supply air downstream of the filters, which on average had been exposed to outdoor air of 40% and 80% relative humidity, was negligible.

Notes: Abstract Several airflow and contaminant dispersion models have been developed to study air distribution in buildings. This paper reports the results of a comprehensive validation of two models: COMIS and CONTAM. The validation process was carried out at three different levels; inter-program comparison; validation with experimental data which was collected in a controlled environment; and finally, validation with field measurement data. At the inter-program level, the airflow rates and pressure values predicted by COMIS and CONTAM for a four-zone paper building were compared with the airflow rates and pressures predicted by CBSAIR, AIRNET and BUS. The results show good agreement between these software programs.The second level of validation compares the models’ predictions with measured data collected in a controlled environment. Fan pressurisation, smoke and tracer gas tests were conducted to estimate the permeability of building envelope components, to locate cracks, and to determine the interzonal airflow rates between rooms. The results confirm that there is good agreement between predictions made by COMIS and CONTAM; there are, however, some differences between these models’ predictions and the measured data.The predictions made by these models were also compared with the results of a tracer gas measurement carried out in a residential building. The predicted and measured values were in good agreement.

Notes: Abstract Building characteristics of dwelling units in the metropolitan Boston area were statistically sorted on the basis of observed associations between the variables. First, associations between categories of house characteristics were determined by cross-table analyses with a pair-wise chi-square test. The key characteristics, which have a significant relationship with many other characteristics, were used to classify the dwelling units into several groups. Two key characteristics, i.e. building type and size of building, were determined. Houses were divided into three groups: single-unit building, small multi-unit (2 to 4 units) building, and large multi-unit (5+ units) building. The building type was not associated with indoor source, but was significantly associated with volume of dwelling unit, air exchange rate, and indoor and outdoor NO2 concentrations. Lower airflow, smaller volume units, and higher outdoor NC2 concentrations, in combination with other factors, result in higher indoor NO2 concentrations in multi-dwelling residential units (apartments and condominiums).

Notes: Abstract A European project started at the end of 1992, in which, in addition to current methods, trained sensory panels were used to investigate office buildings all over Europe. The main aim of this EC-Audit was to develop assessment procedures and guidance on ventilation and source control, to help optimize energy use in buildings while assuring good indoor air quality.In each of nine countries, six or more office buildings were selected. Measurements were performed at five selected locations in each building. The buildings were studied while normally occupied and ventilated to identify the pollution sources in the spaces and to quantify the total pollution load caused by the occupants and their activities, as well as the ventilation systems. The investigation included physical and chemical measurements, assessment of the perceived air quality in the spaces by a trained sensory panel, and measurement of the outdoor air supply to the spaces. A questionnaire for evaluating retrospective and immediate symptoms and perceptions was given to the occupants of the buildings. The building characteristics were described by use of a check-list. The annual energy consumption of the buildings and the weather conditions were registered.This paper presents results and conclusions of the audit in 56 buildings in Europe. However, the analysis and discussions of the results are a summary of the work done, and are focused mainly on comparison between sensory assessments and the other measurements performed.Furthermore, this paper brings the results of the study based on a two-factor analysis. A paper dealing with results on a multifactorial analysis is in preparation.

Notes: Abstract Sources of indoor air pollutants in residential and office environments can be managed to reduce occupant exposures. Techniques for managing indoor air pollution sources include: source elimination, substitution, modification, pretreatment, and altering the amount, location, or time of use. Intelligent source management requires knowledge of the source's emission characteristics, including chemical composition, emission rates, and decay rates. In addition, knowledge of mechanical and natural outdoor air exchange rates, heating/air-conditioning duct flow rates, and local exhaust fan (e.g., kitchen, bathroom) flow rates is needed to determine pollutant concentrations. Finally, indoor air quality (IAQ) models use this information and occupant activity patterns to determine instantaneous and/or cumulative individual exposure. This paper describes a number of residential and office scenarios for various indoor air pollution sources, several ventilation conditions, and typical occupant activity patterns. IAQ model predictions of occupant exposures for these scenarios are given for selected source management options. A one-month period was used to compare exposures; thus, long-term exposure information is not presented in this paper.

Notes: Abstract We have developed a simplified analytical indoor air model that describes the concentrations as a function of position and time in a room following a short-term release of airborne particles or gases. The indoor dispersion model considers the two main physical processes of (1) point-source dispersion with reflection from all walls and (2) the general concentration decay in a room due to room ventilation and surface deposition of pollutants. Comparison of model predictions with experimental indoor measurements conducted by other researchers showed excellent agreement. This model should prove useful for human-health risk estimations in which the inhalation dose resulting from an indoor, short-term release of a contaminant needs to be calculated.

Notes: Abstract Thermal comfort and air quality were studied in three multi-family buildings located in urban environments. Measurements of air velocities close to the supply devices are presented along with measurements of CO, TVOC, NO and NO2. In addition, particle measurements were carried out to check the filter efficiency in one of the buildings (SI) which is specially designed for people with allergy problems. The total air change rate for this building is higher than for normal residential buildings and three different types of air filter are installed in the ventilation system. The results of the thermal comfort measurements in the buildings vary considerably. For two of the buildings thermal comfort can be regarded as acceptable, but can be further improved. The selection and location of the air inlet devices in the third building are not acceptable. The monitoring of the contaminants outdoors and indoors was carried out for diurnal periods. The measured contaminants outside building S1 show good correlation between each other, and the concentrations of gases and particles were considerably lower in the supply air than in the outdoor air outside the apartment where the measurements were made. The importance of not taking samples over too short a period of time is also shown.

Notes: Abstract This paper reports on an investigation into the rates of isothermal vapour transfer taking place between moist air and a hygroscopic solution through a hydrophobic synthetic membrane. The membrane acts as a porous barrier between the phases, being permeable to the vapour but not to the contacting liquid.Experimental results, obtained for a polyethylene membrane with a thickness of 170 μm, show that the total mass transfer coefficient between moist air and a saturated LiCl solution is of the order of 0.078 g/m2hPa at 21°C, at least when the air phase moves at a velocity ranging from 1.5 to 3 m/s. The vapour transfer rate through the membrane is essentially controlled by the convective resistance to vapour transport on the air side and by the resistance to mass transport offered by the membrane. The vapour flux exchanged between the moist air and the hygroscopic solution, although limited by the membrane, appears to be sufficiently high to make the use of vapour membrane exchangers technically feasible in air dehumidification and conditioning.

Notes: Abstract During winter, airborne microfungi were collected from the homes and schools of 19 children sensitized to house dust mites (HDM) and 19 non-atopic control children in the community of Sør-Varanger, northern Norway.The samples were cultivated and microfungal growth was identified microscopically. Indoor humidity, temperature, carbon dioxide (CO2), allergic symptoms and sensitization were registered. Symptom data and information concerning sociodemographic and housing conditions were obtained using a questionnaire. Penicillium was the most common microfungus in both homes and schools, followed by different yeasts, Aspergillus, Cladosporium and Mucor. The number of infected homes was equal in the HDM-sensitized and in the control group, but the mean aerospore counts were higher in the HDM-sensitized than in the control group. The lowest aerospore counts were found in the schools. High airborne spore counts appeared to be related to high indoor humidity. Only four children were sensitized to fungi, and these children were also sensitized to other allergens, such as animal dander and pollen, and suffered from asthma, allergic rhinoconjuncitivits (AR) and atopic dermatitis (AD). Three of these four children also had high counts of aerospores in their homes. However, no consistent association between mould growth and sensitization to moulds could be observed. The health implications of indoor fungal exposure may be multifactorial.

Notes: Abstract Concentrations of airborne particles and microorganisms were assessed as a function of the air exchange rate in two operating theatres equipped with conventional air ventilation systems. The measurements were made with and without human activity (surgery). Under conditions without human activity the effect of the air exchange rate on viable (=microorganisms) and non-viable airborne particles was measured. Under conditions with human activity an investigation was made to determine whether the air exchange rate has a significant influence on airborne particle and bacteria concentrations. In addition, the influence of the number of persons in the operating theatres and the various operating activities were calculated. Statistical differences were found for airborne particle and airborne bacteria concentrations in supply and room air with and without human activity. From the point of view of hygiene, these differences must be considered irrelevant because of the slight margin (less than one logarithmic step) between the values. A comparison of all air exchange rates clearly shows that the number of personnel present in the operating theatre exerts the strongest influence on airborne particle concentration variance in room air. As regards airborne bacteria concentrations in room air, explanation of variance by the parameters air exchange rate, number of persons and operating activity is negligible. Summarizing the low (7.5 and 10/h) and high (15 and 20/h) air exchange rates did not increase the explanation of variance for airborne particle and bacteria concentrations although the differences were significant.