Implementation of robust statistics in the calibration, verification and validation step of model evaluation to better reflect processes concerning total phosphorus load occurring in the catchment

2016 ◽  
Vol 332 ◽  
pp. 83-93 ◽  
Author(s):  
Mieczysław S. Ostojski ◽  
Joanna Gębala ◽  
Paulina Orlińska-Woźniak ◽  
Paweł Wilk
Keyword(s):  
Total Phosphorus ◽  
Model Evaluation ◽  
Robust Statistics ◽  
Verification And Validation ◽  
Phosphorus Load ◽  
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%.

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

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.

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.

scholarly journals R&D for computational cognitive and social models : foundations for model evaluation through verification and validation (final LDRD report).

2008 ◽  
Author(s):  
Alexander Slepoy ◽  
Scott A. Mitchell ◽  
George A. Backus ◽  
Laura A. McNamara ◽  
Timothy Guy Trucano
Keyword(s):  
Model Evaluation ◽  
Verification And Validation ◽  
Social Models

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.

Establishing an empirical equation for the relationship between total suspended solids and total phosphorus concentrations in the downstream Red river water

2020 ◽  
Vol 20 (3) ◽  
pp. 325-332
Author(s):  
Le Nhu Da ◽  
Le Thi Phuong Quynh ◽  
Phung Thi Xuan Binh ◽  
Duong Thi Thuy ◽  
Trinh Hoai Thu ◽  
...  
Keyword(s):  
Total Phosphorus ◽  
Suspended Solids ◽  
Empirical Relationship ◽  
Water Environment ◽  
Total Suspended Solids ◽  
River System ◽  
Red River ◽  
Reservoir Impoundment ◽  
Downstream Section ◽  
Reasonable Prediction

Recently, the Asian rivers have faced the strong reduction of riverine total suspended solids (TSS) flux due to numerous dam/reservoir impoundment. The Red river system is a typical example of the Southeast Asian rivers that has been strongly impacted by reservoir impoundment in both China and Vietnam, especially in the recent period. It is known that the reduction in total suspended solids may lead to the decrease of some associated elements, including nutrients (N, P, Si) which may affect coastal ecosystems. In this paper, we establish the empirical relationship between total suspended solids and total phosphorus concentrations in water environment of the Red river in its downstream section from Hanoi city to the Ba Lat estuary based on the sampling campaigns conducted in the dry and wet seasons in 2017, 2018 and 2019. The results show a clear relationship with significant coefficient between total suspended solids and total phosphorus in the downstream Red river. It is expressed by a simple equation y = 0.0226x0.3867 where x and y stand for total suspended solids and total phosphorus concentrations (mg/l) respectively with the r2 value of 0.757. This equation enables a reasonable prediction of total phosphorus concentrations of the downstream Red river when the observed data of total suspended solids concentrations are available. Thus, this work opens up the way for further studies on the calculation of the total phosphorus over longer timescales using daily available total suspended solids values.

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