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Influence of Sampling Frequency on Estimation of Annual Total Phosphorus and Total Suspended Solids Loads 1
Author(s) -
Jones Amber Spackman,
Horsburgh Jeffery S.,
Mesner Nancy O.,
Ryel Ronald J.,
Stevens David K.
Publication year - 2012
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.2012.00684.x
Subject(s) - sampling (signal processing) , watershed , environmental science , hydrology (agriculture) , sediment , turbidity , water quality , total suspended solids , phosphorus , sampling design , statistics , mathematics , environmental engineering , geology , ecology , geotechnical engineering , population , chemistry , engineering , chemical oxygen demand , filter (signal processing) , oceanography , sociology , wastewater , computer science , biology , paleontology , machine learning , demography , organic chemistry , electrical engineering
The determination of sediment and nutrient loads is typically based on the collection and analysis of grab samples. The frequency and regularity of traditional sampling may not provide representation of constituent loading, particularly in systems with flashy hydrology. At two sites in the Little Bear River, Utah, continuous, high‐frequency turbidity was used with surrogate relationships to generate estimates of total phosphorus and total suspended solids concentrations, which were paired with discharge to estimate annual loads. The high frequency records were randomly subsampled to represent hourly, daily, weekly, and monthly sampling frequencies and to examine the effects of timing, and resulting annual load estimates were compared to the reference loads. Higher frequency sampling resulted in load estimates that better approximated the reference loads. The degree of bias was greater at the more hydrologically responsive site in the upper watershed, which required a higher sampling frequency than the lower watershed site to achieve the same level of accuracy in estimating the reference load. The hour of day and day of week of sampling impacted load estimation, depending on site and hydrologic conditions. The effects of sampling frequency on the determination of compliance with a water quality criterion were also examined. These techniques can be helpful in determining necessary sampling frequency to meet the objectives of a water quality monitoring program.