scholarly journals Summary and trend analysis of water-quality data for the Oakes Test Area, southeastern North Dakota, 1984-2004

2007 ◽  
Author(s):  
Karen R. Ryberg
Keyword(s):  
Water Quality ◽  
North Dakota ◽  
Trend Analysis ◽  
Test Area ◽  
Quality Data ◽  
Water Quality Data

Techniques of trend analysis for monthly water-quality data

1981 ◽  
Author(s):  
Robert M. Hirsch ◽  
James Richard Slack ◽  
Richard A. Smith
Keyword(s):  
Water Quality ◽  
Trend Analysis ◽  
Quality Data ◽  
Water Quality Data

WQTA — A Water Quality Trend Analysis Program

1993 ◽  
Vol 28 (2) ◽  
pp. 311-336 ◽  
Author(s):  
I.K. Tsanis
Keyword(s):  
Water Quality ◽  
Trend Analysis ◽  
Rank Correlation ◽  
Data Bank ◽  
Quality Parameters ◽  
Specific Conductance ◽  
Water Quality Parameters ◽  
Downward Trend ◽  
Quality Data ◽  
Water Quality Data

Abstract A series of programs have been developed using the statistical package Minitab to evaluate trends of water quality parameters over a time period. These programs are included in an interactive program with graphic capabilities called Water Quality Trend Analysis (WQTA). The output files from the retrieval and year programs of the National Water Quality Data Bank (NAQUADAT) are used as input files to the program. The graphic output is obtained using the graphical package Axum. Twelve-month moving averages and the Spearman’s rank correlation are applied for trend assessments. The components of variability (seasonal, trend and random) of the water quality parameters are modelled using linear regression. The methods are applied successfully to selected physical and chemical water quality parameters collected at the mouth of Niagara River, at Niagara-on-the-Lake, during the period 1976–89. The specific conductance was decreasing for the period as the discharge was increasing, due to higher dilution effects. A modest downward trend for total phosphorus was observed for the period 1976–84, and there is no trend between 1984-89. A strong decreasing trend for chloride was observed during the 1977–84 period but this has levelled off since then. A strong upward trend for iron and a weak downward trend for lead was evident over the study period.

Techniques of trend analysis for monthly water quality data

1982 ◽  
Vol 18 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Robert M. Hirsch ◽  
James R. Slack ◽  
Richard A. Smith
Keyword(s):  
Water Quality ◽  
Trend Analysis ◽  
Quality Data ◽  
Water Quality Data
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