Detecting cumulative watershed effects: the statistical power of pairing

Loftis, Jim C.; MacDonald, Lee H.; Streett, Sarah E.; Iyer, Hariharan; Bunte, Kristin

doi:10.1016/s0022-1694(01)00431-0

Cited by 56 publications

(48 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To assess the effects of selective harvesting on Q, SSY and/or MMC we used the paired catchment method which increases the power of analyses to detect disturbance effects (Loftis et al, 2001). The method assumes that the relationship between, for example Q or SSY, of adjacent catchments with similar physiographic characteristics will remain the same unless the vegetation in one catchment is altered.…”

Section: Data Analysis Methodsmentioning

confidence: 99%

Temporary increases in suspended sediment yields following selective eucalypt forest harvesting

Webb¹,

Dragovich

Jamshidi

2012

Forest Ecology and Management

View full text Add to dashboard Cite

Section: Data Analysis Methodsmentioning

confidence: 99%

Temporary increases in suspended sediment yields following selective eucalypt forest harvesting

Webb¹,

Dragovich

Jamshidi

2012

Forest Ecology and Management

View full text Add to dashboard Cite

“…A paired watershed approach [12,28] was used to test the consistency of relationships between daily water table elevation and daily flow for D1 and D2 watersheds during two independent calibration and two independent treatment periods. Table 1 presents the chronology of major silvicultural treatments on D1 and D2 watersheds between 1988 and 2010.…”

Section: Study Design and Treatmentsmentioning

confidence: 99%

“…The treatment effects on the water table elevation for each pair of calibration-treatment data were quantified using mathematical formulations of a paired watershed approach by [28]. Given calibration equation [Equation (2)] and the treatment equation [Equation (3)], the treatment adjustment to the intercept and slope were computed by Equations (4) and (5).…”

Section: Paired Watershed Approachmentioning

confidence: 99%

“…Loftis et al [28] demonstrate advantages of using paired watershed approach compared to single watershed studies. They show that if the correlation coefficient between the responses of the two watersheds is high (r ≥ 0.9), then the required minimum detectable effect is half for paired watershed studies compared to single watershed studies.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Consistency of Hydrologic Relationships of a Paired Watershed Approach

Ssegane¹,

Amatya²,

Chescheir³

et al. 2013

AJCC

View full text Add to dashboard Cite

Paired watershed studies are used around the world to evaluate and quantify effects of forest and water management practices on hydrology and water quality. The basic concept uses two neighboring watersheds (one as a control and another as a treatment), which are concurrently monitored during calibration (pre-treatment) and post-treatment periods. A statistically significant relationship between the control and treatment watersheds is established during calibration period such that any significant shift detected in the relationship during treatment is attributed to the treatment effects. The approach assumes that there is a consistent, quantifiable, and predictable relationship between watershed response variables. This study tests the hypothesis that the hydrologic relationships between control and treatment watersheds for daily water table elevation (WTE) and daily flow data were similar without any statistically significant difference during two different calibration (1988-1989 and 2007-2008) and treatment periods (1995-1996 and 2009), when the control and treatment watersheds were interchanged. The watersheds are two artificially drained loblolly pine forests (D1: 24.7 ha and D2: 23.6 ha) located in coastal North Carolina. Results depicted significantly similar WTE regression relationships during the two calibration periods but significantly different WTE relationships during the two treatment periods with reversed control and treatment watersheds. Calibration and treatment flow relationships, and the mean treatment effects on WTE and flow, before and after treatment reversal were significantly different (α = 0.05). The study also discusses causes of differences in hydrologic relationships and treatment effects for such reversal of treatments during a 21-year span of the study on these two similar and adjacent watersheds. The observed differences in the hydrologic relationships between control and treatment watersheds before and after treatment reversal may be attributed to climate or hydrologic non-stationarity which may affect the reliability of paired watershed approach especially when the calibration periods are short.

show abstract

“…In water quality analysis, it can be used to group sample sites and identify discriminating variables (Yeung, 1999). Loftis et al (2001) suggested that monitoring to evaluate change and costeffectiveness of pollution control can be done on the basis of paired watershed experiments. This approach is useful to determine the effect of a particular treatment on water quality.…”

Section: Trend Analysis and Principal Component Analysesmentioning

confidence: 99%

Scatterscore: A Reconnaissance Method To Evaluate Changes In Water Quality

Kim

Cardone

2005

Environ Monit Assess

View full text Add to dashboard Cite

Water quality data collected in periodic monitoring programs are often difficult to evaluate, especially if the number of parameters is large, the sampling schedule varies, and values are of different orders of magnitude. The Scatterscore Water Quality Evaluation was developed to yield a quantitative score, based on all measured variables in periodic water quality reports, indicating positive, negative or random change. This new methodology calculates a reconnaissance score based on the differences between up-gradient (control) versus down-gradient (treatment) water quality data sets. All parameters measured over a period of time at two or more sampling points are compared. The relationship between the ranges of measured values and the ratio of the medians for each parameter produces a data point that falls into one of four sections on a scattergram. The number and average values of positive, negative and random change points is used to calculate a Scatterscore that indicates the magnitude and direction of overall change in water quality. The Scatterscore Water Quality Evaluation, a reconnaissance method to track general changes, has been applied to 20 sites at which coal utilization by-products (CUB) were used to control acid mine drainage (AMD).

show abstract

Detecting cumulative watershed effects: the statistical power of pairing

Cited by 56 publications

References 13 publications

Temporary increases in suspended sediment yields following selective eucalypt forest harvesting

Temporary increases in suspended sediment yields following selective eucalypt forest harvesting

Consistency of Hydrologic Relationships of a Paired Watershed Approach

Scatterscore: A Reconnaissance Method To Evaluate Changes In Water Quality

Contact Info

Product

Resources

About