Event Title

Impact of Sampling Frequency on Annual Load Estimation of Total Phosphorus and Total Suspended Solids

Location

Eccles Conference Center

Event Website

http://water.usu.edu/

Start Date

4-2-2009 3:00 PM

End Date

4-2-2009 3:20 PM

Description

Compliance with water quality standards for sediment and nutrients is typically based on the collection and analysis of grab samples. These data generally are not collected with enough frequency or regularity to provide representation of the constituent loading, yet regulatory decisions and the investment of significant resources for water quality improvement are routinely based upon these numbers. In the Little Bear River watershed in northern Utah, USA, continuous, high frequency measurements of turbidity were used to generate high frequency estimates of instream total phosphorus (TP) and total suspended solids (TSS) concentrations through surrogate relationships. The concentration estimates were paired with discharge data to estimate TP and TSS loading (reference loads). The high frequency records were then subsampled to create random subsets representing hourly, daily, weekly, and monthly sampling frequencies. Additionally, subsets were created to examine the effects of randomizing the time of day and the day of week of sampling. The annual load estimates resulting from the decimated subsets were compared to the reference loads. Results show that high frequency surrogate measures generally improved estimates of TP and TSS loads in comparison to grab sampling. Overall, higher frequency sampling resulted in load estimates that better approximated the reference loads, although the amount of bias varied between sites. Additionally, the hour of the day and the day of the week on which sampling is conducted can have an impact on load estimation, depending on sampling location and hydrologic conditions.

This document is currently not available here.

Share

COinS
 
Apr 2nd, 3:00 PM Apr 2nd, 3:20 PM

Impact of Sampling Frequency on Annual Load Estimation of Total Phosphorus and Total Suspended Solids

Eccles Conference Center

Compliance with water quality standards for sediment and nutrients is typically based on the collection and analysis of grab samples. These data generally are not collected with enough frequency or regularity to provide representation of the constituent loading, yet regulatory decisions and the investment of significant resources for water quality improvement are routinely based upon these numbers. In the Little Bear River watershed in northern Utah, USA, continuous, high frequency measurements of turbidity were used to generate high frequency estimates of instream total phosphorus (TP) and total suspended solids (TSS) concentrations through surrogate relationships. The concentration estimates were paired with discharge data to estimate TP and TSS loading (reference loads). The high frequency records were then subsampled to create random subsets representing hourly, daily, weekly, and monthly sampling frequencies. Additionally, subsets were created to examine the effects of randomizing the time of day and the day of week of sampling. The annual load estimates resulting from the decimated subsets were compared to the reference loads. Results show that high frequency surrogate measures generally improved estimates of TP and TSS loads in comparison to grab sampling. Overall, higher frequency sampling resulted in load estimates that better approximated the reference loads, although the amount of bias varied between sites. Additionally, the hour of the day and the day of the week on which sampling is conducted can have an impact on load estimation, depending on sampling location and hydrologic conditions.

https://digitalcommons.usu.edu/runoff/2009/AllAbstracts/4