Factors affecting the efficiency of some estimators of fluvial total phosphorus load

1988 ◽  
Vol 24 (9) ◽  
pp. 1535-1540 ◽  
Author(s):  
Thomas C. Young ◽  
Joseph V. DePinto ◽  
Thomas M. Heidtke
Keyword(s):  
Total Phosphorus ◽  
Phosphorus Load ◽  
Factors Affecting ◽  
Total Phosphorus Load

Estimation of particulate nutrient load usingturbidity meter

2006 ◽  
Vol 53 (2) ◽  
pp. 311-320 ◽  
Author(s):  
K. Yamamoto ◽  
T. Suetsugi
Keyword(s):  
Total Phosphorus ◽  
Flow Rate ◽  
Estimation Error ◽  
Nutrient Load ◽  
Nutrient Loads ◽  
Phosphorus Load ◽  
Regression Curve ◽  
Linear Relationships ◽  
Particulate Nutrients ◽  
Total Phosphorus Load

The “Nutrient Load Hysteresis Coefficient” was proposed to evaluate the hysteresis of the nutrient loads to flow rate quantitatively. This could classify the runoff patterns of nutrient load into 15 patterns. Linear relationships between the turbidity and the concentrations of particulate nutrients were observed. It was clarified that the linearity was caused by the influence of the particle size on turbidity output and accumulation of nutrients on smaller particles (diameter <23 μm). The L-Q-Turb method, which is a new method for the estimation of runoff loads of nutrients using a regression curve between the turbidity and the concentrations of particulate nutrients, was developed. This method could raise the precision of the estimation of nutrient loads even if they had strong hysteresis to flow rate. For example, as for the runoff load of total phosphorus load on flood events in a total of eight cases, the averaged error of estimation of total phosphorus load by the L-Q-Turb method was 11%, whereas the averaged estimation error by the regression curve between flow rate and nutrient load was 28%.

A Simple Method for Predicting the Capacity of a Lake for Development Based on Lake Trophic Status

1975 ◽  
Vol 32 (9) ◽  
pp. 1519-1531 ◽  
Author(s):  
P. J. Dillon ◽  
F. H. Rigler
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
Total Phosphorus ◽  
Water Budget ◽  
Trophic Status ◽  
Phosphorus Concentration ◽  
Phosphorus Load ◽  
Secchi Disc ◽  
Total Phosphorus Concentration ◽  
Lake Trophic Status

A general technique is presented for calculating the capacity of a lake for development based on quantifiable relationships between nutrient inputs and water quality parameters reflecting lake trophic status. Use of the technique for southern Ontario lakes is described. From the land use and geological formations prevalent in a lake’s drainage basin, the phosphorus exported to the lake in runoff water can be calculated, which, when combined with the input directly to the lake’s surface in precipitation and dry fallout, gives a measure of the natural total phosphorus load. From the population around the lake, the maximum artificial phosphorus load to the lake can be calculated and, if necessary, modified according to sewage disposal facilities used. The sum of the natural and artificial loads can be combined with a measure of the lake’s morphometry expressed as the mean depth, the lake’s water budget expressed as the lake’s flushing rate, and the phosphorus retention coefficient of the lake, a parameter dependent on both the lake’s morphometry and water budget, to predict springtime total phosphorus concentration in the lake. Long-term average runoff per unit of land area, precipitation, and lake evaporation data for Ontario provide a means of calculating the necessary water budget parameters without expensive and time-consuming field measurements. The predicted spring total phosphorus concentration can be used to predict the average chlorophyll a concentration in the lake in the summer, and this, in turn, can be used to estimate the Secchi disc transparency. Thus, the effects of an increase in development on a lake’s water quality can be predicted. Conversely, by setting limits for the "permissible" summer average chlorophyll a concentration or Secchi disc transparency, the "permissible" total phosphorus concentration at spring overturn can be calculated. This can be translated into "permissible" artificial load, which can then be expressed as total allowable development. This figure can be compared to the current quantity of development and recommendations made concerning the desirability of further development on the lake.

scholarly journals Excessive application of chemical fertilizer and organophosphorus pesticides induced total phosphorus loss from planting causing surface water eutrophication

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Liyuan Liu ◽  
Xiangqun Zheng ◽  
Xiaocheng Wei ◽  
Zhang Kai ◽  
Yan Xu
Keyword(s):  
Surface Water ◽  
Total Phosphorus ◽  
Structural Equation ◽  
Organophosphorus Pesticides ◽  
Equation Model ◽  
Path Coefficient ◽  
Natural Conditions ◽  
Factors Affecting ◽  
Water Eutrophication ◽  
Anthropogenic Drivers

AbstractTotal phosphorus (TP) loss from planting was one of the resources causing agricultural non-point source pollution. It is significant to clarify the factors influencing TP loss, as well as explore the relationship between TP loss from planting and surface water eutrophication for making recommendations on the reduction of environmental pollution. In this study, the minimum and maximum of average TP loss was appeared in Qinghai and Shandong province with the TP loss of 7.7 × 102 t and 7.5 × 103 t from 2012 to 2014, respectively. The results of structural equation model (SEM) indicating that the effect of anthropogenic drivers on TP loss was more important than natural conditions due to the higher path coefficient of anthropogenic drivers (0.814) than that of natural conditions (0.130). For anthropogenic drivers, the path coefficients of usage of fertilizer and pesticides, which was often excessively applied in China, were 0.921 and 0.909, respectively causing they the two dominant factors affecting TP loss. Annual precipitation and relative humidity, which were belongs to natural conditions, increased TP loss by enhancing leaching and surface runoff. However, light duration could reduce TP loss by promoting crop growth and increasing TP absorption of crops, with a path coefficient of − 0.920. TP loss of each province in per unit area from planting was significantly correlated with TP concentration of its surface water (p < 0.05), suggesting that TP loss from planting was the main factor causing surface water eutrophication. This study targeted presented three proposals to reduce the TP loss from planting, including promotion of scientific fertilization technologies, restriction of organophosphorus pesticides, and popularization of water saving irrigation technologies. These findings as well as suggestions herein would provide direction for the reduction of TP loss from planting.

Response of Lake Ontario to Reductions in Phosphorus Load, 1967–82

1987 ◽  
Vol 44 (12) ◽  
pp. 2059-2068 ◽  
Author(s):  
R. J. J. Stevens ◽  
M. A. Neilson
Keyword(s):  
Response Time ◽  
Multiple Regression ◽  
Total Phosphorus ◽  
Algal Biomass ◽  
Soluble Reactive Phosphorus ◽  
Lake Ontario ◽  
Multiple Regression Equation ◽  
Phosphorus Load ◽  
N:P Ratios ◽  
Reactive Phosphorus

Total phosphorus (TP) loading to Lake Ontario has declined from 14 600 t∙yr−1 in 1969 to 8900 t∙yr−1 in 1982. Midlake spring TP has responded rapidly to these reductions, decreasing at the rate of 1.09 μg∙L−1∙yr−1 from a maximum of 30.6 μg∙L−1 in 1973 to 12.8 μg∙L−1 in 1982. Spring soluble reactive phosphorus (SRP) exhibited a proportionally larger decrease than TP such that 1982 SRP was 33% of 1973 levels, compared with 42% for TP. A multiple regression equation indicated an 80% response time of spring TP within 2 yr and a 90% response time within 4 yr. Spring nitrate plus nitrite has increased since 1969 at the rate of 9.5 μg∙L−1∙yr−1 causing N:P ratios to increase from 10 to 32. Mean summer epilimnetic TP declined at the rate of only 0.3 μg∙L−1∙yr−1 from 1977 to 1982 so that mean summer TP levels now exceed spring TP by 1–2 μg∙L−1. This suggests that loading to the lake during the stratified period has not shown a similar decline and may be responsible for the lack of a trend in algal biomass indicators during this period.

Factors Affecting the Relation Between Phosphorus and Chlorophyll a in Midwestern Reservoirs

1983 ◽  
Vol 40 (2) ◽  
pp. 192-199 ◽  
Author(s):  
Mark V. Hoyer ◽  
John R. Jones
Keyword(s):  
Chlorophyll A ◽  
Total Phosphorus ◽  
Suspended Solids ◽  
Phosphorus Concentration ◽  
Zooplankton Abundance ◽  
Factors Affecting ◽  
Inorganic Solids ◽  
Flushing Rate ◽  
Natural Lakes ◽  
The Mean

The mean chlorophyll a (mg/m3) yield per unit of total phosphorus (mg/m3) (P–C relation) in 96 midwest reservoirs and the variance about this yield was similar to relations for natural lakes reported in the literature. The remaining error term for this relation could not be reduced by adding variables for nitrogen, zooplankton abundance, or hydrologic flushing rate. In reservoirs with ratios of total nitrogen to total phosphorus of less than 10, nitrogen accounted for the same amount of variance in chlorophyll a as did phosphorus. Using partial regression path analysis, we found that when the concentration of phosphorus was held constant, increasing the concentration of inorganic suspended solids (mg/L) significantly decreased chlorophyll a. The following multivariate equation was developed to account for the effect of inorganic solids on the P–C relation:[Formula: see text]This equation accounted for 7% more variance than the univariate equation and the 95% predictive confidence interval, at an average phosphorus concentration, was reduced by 10%. This equation should be useful for predicting chlorophyll a in lakes with inorganic turbidities. When Secchi transparency data were regressed on both chlorophyll a and inorganic suspended solids, they accounted for 42% more variance in transparency than did chlorophyll a.Key words: lake trophic state, nitrogen, zooplankton, flushing rate, suspended solids, reservoirs

scholarly journals Impact of calculation method, sampling frequency and hysteresis on suspended solids and total phosphorus load estimations in cold climate

2017 ◽  
Vol 48 (6) ◽  
pp. 1594-1610 ◽  
Author(s):  
Pasi Valkama ◽  
Olli Ruth
Keyword(s):  
Water Quality ◽  
Total Phosphorus ◽  
Suspended Solids ◽  
Sampling Frequency ◽  
Cold Climate ◽  
Short Term ◽  
Load Calculation ◽  
Daily Sampling ◽  
Continuous Measuring ◽  
Total Phosphorus Load

Abstract Load calculations of nutrients and suspended solids (SS) transported by rivers are usually based on discrete water samples. Water quality changes in cold climate regions often occur very rapidly and therefore discrete samples are unrepresentative of the range of water quality occurring. This leads to errors of varying magnitude in load calculation. High-resolution turbidity data were used to determine the SS and total phosphorus (TP), and paired with discharge to determine loads from two small catchments in southern Finland. The effect of sampling frequency was investigated by artificially sub-sampling the high frequency concentrations. Regardless of the sampling frequency, the TP load was more likely underestimated while using discrete samples. To achieve ±20% accuracy compared with the reference load, daily sampling should be performed. Hysteresis was detected to have an impact on TP load. Hysteresis analysis also revealed the main source of the TP to be in the fields of the catchment. Continuous measuring proved to be a valuable method for defining loads and short-term fluctuations in water quality in small clayey watercourses in a boreal cold climate, where the climate change will increase the frequency of winter floods.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

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