Risk analysis of seasonal stream water quality management

2010 ◽  
Vol 62 (9) ◽  
pp. 2075-2082 ◽  
Author(s):  
Manoj Jha ◽  
Roy Gu
Keyword(s):  
Water Quality ◽  
Stream Water ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Quality Data ◽  
Stream Water Quality ◽  
Water Quality Data ◽  
Control Programs ◽  
Des Moines ◽  
Seasonal Discharge

Seasonal discharge programs, which take advantage of temporal variation of stream assimilative capacity, are cost effective. However, these seasonal discharge control programs should not increase the risk of water quality violations. A method is presented to estimate the allowable pollutant loads under both seasonal and non-seasonal discharge control programs for a single discharger that maintains the same level of risk of water quality violation. An enhanced in-stream water quality model QUAL2E-UNCAS was applied to a 39-km river reach of the Des Moines River below Des Moines Sewage Treatment Plant (DMSTP) in Iowa. The model was calibrated for dissolved oxygen (DO), biological oxygen demand (BOD), and ammonia as nitrogen with standard errors of 10, 17, and 23% by comparing with the observed water quality data. Monte-Carlo simulation technique was then implemented for seasonal and non-seasonal discharge program to assess the water quality violation risk and the allowable pollutant load. The results indicated that the four-seasonal program offers about 136% increase in BOD loading and 61% increase in ammonia loading when compared with the non-seasonal program without any increase in the violation probabilities, whereas the two-seasonal program only offers 13% decrease in BOD loading and 56% increase in ammonia loading. It is found that the multi-discharge program was beneficial for both water quality indicators, and thus provides a way of reducing the overall cost of waste treatment.

scholarly journals The impact of conifer harvesting on stream water quality: the Afon Hafren, mid-Wales

2004 ◽  
Vol 8 (3) ◽  
pp. 503-520 ◽  
Author(s):  
C. Neal ◽  
B. Reynolds ◽  
M. Neal ◽  
H. Wickham ◽  
L. Hill ◽  
...  
Keyword(s):  
Water Quality ◽  
Stream Water ◽  
Strong Support ◽  
Shallow Groundwater ◽  
Water Quality Monitoring ◽  
Quality Data ◽  
Stream Water Quality ◽  
Catchment Scale ◽  
Water Quality Data ◽  
The Impact

Abstract. Results for long term water quality monitoring are described for the headwaters of the principal headwater stream of the River Severn, the Afon Hafren. The results are linked to within-catchment information to describe the influence of conifer harvesting on stream and shallow groundwater quality. A 19-year record of water quality data for the Hafren (a partially spruce forested catchment with podzolic soil) shows the classic patterns of hydrochemical change in relation to concentration and flow responses for upland forested systems. Progressive felling of almost two-thirds of the forest over the period of study resulted in little impact from harvesting and replanting in relation to stream water quality. However, at the local scale, a six years’ study of felling indicated significant release of nitrate into both surface and groundwater; this persisted for two or three years before declining. The study has shown two important features. Firstly, phased felling has led to minimal impacts on stream water. This contrasts with the results of an experimental clear fell for the adjacent catchment of the Afon Hore where a distinct water quality deterioration was observed for a few years. Secondly, there are localised zones with varying hydrology that link to groundwater sources with fracture flow properties. This variability makes extrapolation to the catchment scale difficult without very extensive monitoring. The implications of these findings are discussed in relation to strong support for the use of phased felling-based management of catchments and the complexities of within catchment processes. Keywords: deforestation, water quality, acidification, pH, nitrate, alkalinity, ANC, aluminium, dissolved organic carbon, Plynlimon, forest, spruce, Afon Hafren, podzol

scholarly journals Response of Water Quality to Landscape Patterns in an Urbanized Watershed in Hangzhou, China

2020 ◽  
Vol 12 (14) ◽  
pp. 5500 ◽  
Author(s):  
Yu Song ◽  
Xiaodong Song ◽  
Guofan Shao
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Land Use ◽  
Stream Water ◽  
Land Use Changes ◽  
Landscape Patterns ◽  
Quality Data ◽  
Stream Water Quality ◽  
Water Quality Data ◽  
Algae Biomass

Intense human activities and drastic land use changes in rapidly urbanized areas may cause serious water quality degradation. In this study, we explored the effects of land use on water quality from a landscape perspective. We took a rapidly urbanized area in Hangzhou City, China, as a case study, and collected stream water quality data and algae biomass in a field campaign. The results showed that built-up lands had negative effects on water quality and were the primary cause of stream water pollution. The concentration of total phosphorus significantly correlated with the areas of residential, industrial, road, and urban greenspace, and the concentration of chlorophyll a also significantly correlated with the areas of these land uses, except residential land. At a landscape level, the correlation analysis showed that the landscape indices, e.g., dominance, shape complexity, fragmentation, aggregation, and diversity, all had significant correlations with water quality parameters. From the perspective of land use, the redundancy analysis results showed that the percentages of variation in water quality explained by the built-up, forest and wetland, cropland, and bareland decreased in turn. The spatial composition of the built-up lands was the main factor causing stream water pollution, while the shape complexities of the forest and wetland patches were negatively correlated with stream water pollution.

Post-fire water-quality response in the western United States

2018 ◽  
Vol 27 (3) ◽  
pp. 203 ◽  
Author(s):  
Ashley J. Rust ◽  
Terri S. Hogue ◽  
Samuel Saxe ◽  
John McCray
Keyword(s):  
United States ◽  
Water Quality ◽  
Stream Water ◽  
Western United States ◽  
Change Point Analysis ◽  
Quality Data ◽  
Stream Water Quality ◽  
Nitrogen And Phosphorus ◽  
Water Quality Data ◽  
Quality Response

Wildfires are increasing in size and severity in forested landscapes across the Western United States. Not only do fires alter land surfaces, but they also affect the surface water quality in downstream systems. Previous studies of individual fires have observed an increase in various forms of nutrients, ions, sediments and metals in stream water for different post-fire time periods. In this research, data were compiled for over 24 000 fires across the western United States to evaluate post-fire water-quality response. The database included millions of water-quality data points downstream of these fires, and was synthesised along with geophysical data from each burned watershed. Data from 159 fires in 153 burned watersheds were used to identify common water-quality response during the first 5 years after a fire. Within this large dataset, a subset of seven fires was examined further to identify trends in water-quality response. Change-point analysis was used to identify moments in the post-fire water-quality data where significant shifts in analyte concentrations occurred. Evaluating individual fires revealed strong initial increases or decreases in concentrations, depending on the analyte, that are masked when averaged over 5 years. Evidence from this analysis shows significant increases in nutrient flux (different forms of nitrogen and phosphorus), major-ion flux and metal concentrations are the most common changes in stream water quality within the first 5 years after fire. Dissolved constituents of ions and metals tended to decrease in concentration 5 years after fire whereas particulate matter concentration continued to increase. Assembling this unique and extensive dataset provided the opportunity to determine the most common post-fire water-quality changes in the large and diverse Western USA. Results from this study could inform studies in other parts of the world, will help parameterise and validate post-fire water-quality models, and assist communities affected by wildfire to anticipate changes to their water quality.

scholarly journals Assessing environmental impacts on stream water quality: the use of cumulative flux and cumulative flux difference approaches to deforestation of the Hafren Forest, mid-Wales

2002 ◽  
Vol 6 (3) ◽  
pp. 421-432 ◽  
Author(s):  
C. Neal
Keyword(s):  
Water Quality ◽  
Time Series ◽  
Stream Water ◽  
Quality Data ◽  
Stream Water Quality ◽  
Water Quality Data ◽  
Paired Catchment ◽  
Flux Difference ◽  
Clear Fell ◽  
Acid Neutralisation

Abstract. A method for examining the impacts of disturbance on stream water quality based on paired catchment "control" and "response" water quality time series is described in relation to diagrams of cumulative flux and cumulative flux difference. The paper describes the equations used and illustrates the patterns expected for idealised flux changes followed by an application to stream water quality data for a spruce forested catchment, the Hore, subjected to clear fell. The water quality determinands examined are sodium, chloride, nitrate, calcium and acid neutralisation capacity. The anticipated effects of felling are shown in relation to reduction in mist capture and nitrate release with felling as well as to the influence of weathering and cation exchange mechanisms, but in a much clearer way than observed previously using other approaches. Keywords: Plynlimon, stream, Hore, acid neutralisation capacity, calcium, chloride, nitrate, sodium, cumulative flux, flux

Application of a Nonparametric Approach for Monitoring and Detecting Trends in Water Quality Data for the St

1986 ◽  
Vol 21 (2) ◽  
pp. 153-167 ◽  
Author(s):  
Michael D. Cailas ◽  
George Cavadias ◽  
Ronald Gehr
Keyword(s):  
Water Quality ◽  
Parametric Method ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Quality Data ◽  
Seasonal Adjustment ◽  
Positive Trend ◽  
Water Quality Data ◽  
Nonparametric Approach

Abstract To overcome some of the restrictions due to the irregular structure of water quality data, a nonparametric approach has been developed based on Kendall’s T and a seasonal adjustment model, which enables one to test for the significance of trends as well as to monitor the trend variations with time. This methodology has been applied to water quality data for the St. Lawrence river obtained from Environment Canada and the municipality of Varennes. The results from the first source indicate that a positive trend is developing for conductivity and pH downstream from the Island of Montreal, whereas upstream from the Island pH is the only parameter indicating a positive trend. Data from the municipality of Varennes, due to their excellent quality, were used to verify the validity of the previous results as well as the reliability of the applied methodology. Analysis of the Varennes data with a parametric method indicated that a positive trend in pH is indeed evident. This finding will be of consequence for future studies to ascertain the effect on the river of the new Montreal Urban Community Sewage Treatment Plant.

scholarly journals A GIS-based spatiotemporal study of the variability of water quality in the Dubai Creek, UAE

2015 ◽  
Vol 51 (3) ◽  
pp. 219-232 ◽  
Author(s):  
Tarig A. Ali ◽  
Maruf Mortula ◽  
Serter Atabay ◽  
Ehsan Navadeh
Keyword(s):  
Water Quality ◽  
Regression Analysis ◽  
Chlorophyll A ◽  
Multiple Logistic Regression Analysis ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Ordinary Least Squares ◽  
Spatiotemporal Variability ◽  
Quality Data ◽  
Water Quality Data

This paper presents the outcomes of a study on the water quality of Dubai Creek which aimed to assess its eutrophication status. Field water quality data from stations along the creek collected in 2012 and 2013 were used. Ordinary least squares (OLS) and spatial autocorrelation analyses were used as part of geographic information system (GIS)-based exploratory regression analysis to study the relationship between chlorophyll-a and nutrients, specifically total nitrogen and phosphate. Multiple logistic regression analysis was used to study the vulnerability of the creek to eutrophication. Results showed unique trends of spatiotemporal variability of chlorophyll-a and nutrients. OLS modeling showed high correlation between field and modeled chlorophyll-a values between Al Garhoud Bridge and Sanctuary stations, located about 2 km upstream and downstream of the Sewage Treatment Plant (STP) Outfall station. Furthermore, results showed the lower half of the creek was more vulnerable to eutrophication than the upper, which was believed to be due to the location of the STP station, poor flushing, shallow water depth, and irregular circulation patterns in the creek. Accordingly, this study recommends development of a mitigation plan in order to control the levels of nutrients in the creek.

Sign in / Sign up

Export Citation Format

Share Document