scholarly journals Periphyton biomass and community compositions as indicators of water quality in the Lower Grand River hydrologic unit, Missouri and Iowa, 2011–18

Author(s):  
Heather M. Krempa
2004 ◽  
Author(s):  
Pradeep Kumar Goel ◽  
Ramesh P. Rudra ◽  
Javeed Khan ◽  
Bahram Gharabaghi ◽  
Samaresh Das ◽  
...  

1996 ◽  
Vol 23 (4) ◽  
pp. 893-903 ◽  
Author(s):  
A. Tyagi ◽  
M. Sharma ◽  
E. McBean

Statistical models are developed for the estimation of phosphorus concentrations for different seasons and locations using routinely monitored water quality parameters in the Grand River Basin. Two methods of modelling, namely the best subset model and the stepwise regression method based on R2 and F values, are described. The best subset modelling procedure enables comparison between full model (containing all the independent variables) and subset models (containing subsets of independent variables). For correlated independent variables, the best subset modelling procedure is shown to provide a better model than the stepwise regression procedure. The statistical modelling results indicate that suspended solids play an important role in the prediction of phosphorus levels and consequently decreasing suspended solids would decrease the growth of aquatic plants in the Grand River Basin. Key words: regression modelling, water quality, phosphorus, suspended solids, rivers, statistics.


2020 ◽  
Author(s):  
Jillian Ashton ◽  
◽  
Peter J. Wampler ◽  
Tara Kneeshaw

1998 ◽  
Vol 55 (6) ◽  
pp. 1443-1453 ◽  
Author(s):  
Eugen Rott ◽  
Hamish C Duthie ◽  
Eveline Pipp

Diatom analysis discriminates between the impacts on river water quality of treated urban wastewaters and diffuse nutrient sources from farmland. Evaluation of organic pollution and trophic levels in the Grand River, Ontario, using two diatom indices shows a clear differentiation among 10 sampling sites over a distance of 214 km. Sites in the central reaches that are influenced by both urban discharges and agricultural runoff have the lowest water quality. The ranking of sites according to both diatom indices is consistently independent of substratum and seasonality. Ordination of samples by multivariate analysis results in a primary separation of the spring and summer communities and a secondary separation of upper, central, and lower reaches. Substratum differences are only apparent at the tertiary level, and mainly for midsummer samples from the upper reaches. Canonical correspondence analysis shows that the largest portion of the observed variability in species composition can be explained by a seasonal gradient related to temperature and by longitudinal gradients of nitrate-nitrogen, conductivity, and chloride. Differences in species composition between nutrient-rich sites and polluted sites are identified. Compared with a study conducted in the 1960s, the Grand River shows clear signs of increased eutrophication.


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