ABSTRACT: Suspended sediment causes a range of environmental damage, including benthic smothering, irritation fish gills, and transport sorbed contaminants. Much the impact, while remains suspended, is related to its light attenuation, which reduces visual in water availability for photosynthesis. Thus measurement optical attributes suspended matter many instances more relevant than mass concentration. Nephelometric turbidity, an index scattering by particles, has been widely used as simple,...

ABSTRACT Sunlight inactivation in fresh (river) water of fecal coliforms, enterococci, Escherichia coli , somatic coliphages, and F-RNA phages from waste stabilization pond (WSP) effluent was compared. Ten experiments were conducted outdoors 300-liter chambers, held at 14°C (mean river temperature). ( k S ) rates, as a function cumulative global solar radiation (insolation), all more than 10 times higher the corresponding dark D rates enclosed (control) chambers. The overall ranking (from...

Abstract Water quality, habitat, and biota were compared during spring amongst c. 100 m reaches on 11 streams draining pasture, native (podocarp‐broadleaf) forest, exotic pine forest established pasture 15 years previously. Differences greatest between the streams. Only 1–3% of incident light reached whereas 30% Pasture had 2.2°C higher mean temperature than streams, 5‐fold nitrate, 30‐fold algal biomass, 11‐fold gross photosynthesis. Native 60% wider with intermediate. Pine 3‐fold suspended...

Abstract River and stream rehabilitation projects are increasing in number, but the success or failure of these has rarely been evaluated, extent to which buffers can restore riparian function species composition is not well understood. In New Zealand widespread conversion forest agricultural land caused degradation streams ecosystems. We assessed nine buffer zone schemes North Island, that had fenced planted (age range from 2 24 years) compared them with unbuffered control reaches upstream...

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Abstract A computer model for stream water temperature was developed, and tested in a small pasture near Hamilton, New Zealand. The quantifies shading by riparian vegetation, hillsides, banks using three coefficients: canopy angle, topography shade factor. Shade measured directly found to vary significantly along the channel. Using maximum shade, close match achieved between observed predicted daily minimum bed sediment temperature. Model predictions of incoming outgoing long‐wave radiation...

Inactivation (loss of culturability) by sunlight enterococci and fecal coliforms within sewage effluent diluted in seawater was investigated field experiments. In most experiments, 500-ml flasks pure silica were used to confine activated sludge 2% (vol/vol) seawater. bacteria these (diameter, 0.1 m) faster than either open chambers (depth, 0.25 or patches dyed (depth order, 1 m), probably because the longer light paths latter two types experiment, which caused greater attenuation sunlight....

Abstract. Relationships between land use and water quality are complex with interdependencies, feedbacks, legacy effects. Most river studies have assessed catchment as areal coverage, but here, we hypothesize test whether intensity – the inputs (fertilizer, livestock) activities (vegetation removal) of is a better predictor environmental impact. We New Zealand (NZ) case study because it has had one highest rates agricultural intensification globally over recent decades. interpreted state...

Abstract In the Hakarimata Range, west of Hamilton, New Zealand, second‐order streams appear to be wider in native than pasture catchments, whereas pine plantations (18 years old) suffering active stream‐bank erosion. A working hypothesis explain these observations was that vegetation replacing original forest encroaches on stream channel, causing it become narrower. To test hypothesis, channel widths were measured up and down "transitions" from 20 different size marginal ranges Waikato...

Faecal bacterial dynamics during flood events were studied in the Topehaehae Stream near Morrinsville, New Zealand, a catchment used for grazing dairy and beef cattle. During rising limb of natural event, E. coli concentration rose by more than 2 orders magnitude peaked at 41,000 cfu/100 mL. correlated closely with turbidity over both variables close to time maximum flow acceleration rather peak flow. An artificial on same stream, created releasing water from supply reservoir fine weather no...

Black targets have a major theoretical advantage over reflective such as the Secchi disk for assessing visual clarity of water because their sighting ranges depend only on two optical properties water: beam attenuation coefficient and diffuse coefficient. The theory visibility black objects applies to observations made with in 11 rivers eight lakes ranging 60‐fold clarity. horizontal range is similar practical importance water, aquatic animals well man, yields an immediate estimate expected...

Inactivation in sunlight of fecal coliforms (FC) and enterococci (Ent) from sewage meatworks effluents was measured 300-liter effluent-seawater mixtures (2% vol/vol) held open-topped chambers. Dark inactivation rates (kDs) were (from log-linear survival curves) enclosed chambers 6-liter pots. The kD for FC 2 to 4 times that Ent, generally slower at lower temperatures. Sunlight described terms shoulder size (n) the slope (k) portion curve as a function global solar insolation UV-B fluence. n...

Abstract The water quality impact of a herd 246 dairy cows crossing stream ford was documented. Two cow crossings produced plumes turbid associated with very high concentrations faecal indicator bacteria (Escherichia coli) and suspended solids (SS) total nitrogen (TN). On the first crossing, towards milking shed, were tightly‐bunched sharp spike contamination (E. coli peaking at 50 000 cfu/100 ml). After milking, wandered back across as individuals or small groups, contaminants less...

Abstract A programme of research to characterise, classify, and model New Zealand rivers according hydrological, water quality, biological properties is introduced. The results are detailed in the accompanying eight papers. These studies provide first national perspective on quality biology Zealand's using a consistent methodology. They also step toward providing managers with robust models for predicting effects aquatic biota changes flow regimes catchment land use. synthesis given this...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCopper and cadmium uptake by estuarine sedimentary phasesRobert J. Davies-Colley, Peter O. Nelson, Kenneth WilliamsonCite this: Environ. Sci. Technol. 1984, 18, 7, 491–499Publication Date (Print):July 1, 1984Publication History Published online1 May 2002Published inissue 1 July 1984https://pubs.acs.org/doi/10.1021/es00125a002https://doi.org/10.1021/es00125a002research-articleACS PublicationsRequest reuse permissionsArticle...

Davies-Colley, Robert J., David G. Smith, C. Ward, Graham Bryers, B. McBride, John M. Quinn, and Mike R. Scarsbrook, 2011. Twenty Years of New Zealand’s National Rivers Water Quality Network: Benefits Careful Design Consistent Operation. Journal the American Resources Association (JAWRA) 47(4):750-771. DOI: 10.1111/j.1752-1688.2011.00554.x Abstract: This paper reviews Network (NRWQN), which is now in its third decade monitoring. The NRWQN noteworthy for being operationally stable throughout...