Jabez Water Quality Data Disclaimers

This disclaimer applies to water quality data collected by the Maryland Department of Natural Resources from the Jabez Branch tributary restoration and associated sites from May to November 2024. All 2024 monitoring data was collected while construction was ongoing in the restoration reach.

Data included from this timeframe were collected using two methods: continuous monitoring and discrete measurements.

Sondes collecting continuous water quality measurements have, or have likely, experienced significant fouling at times that may have resulted in some unreliable and/or inaccurate data.

There is a higher degree of confidence in the accuracy of the continuous data from the first few hours of a sonde's deployment. Data collected across the sites indicated potentially frequent fouling of the sondes, sometimes within a day after deployment. We believe these early readings are least likely to be impacted from fouling from iron flocculant, sediment, and/or other materials.

Discrete readings are one-time measurements taken with handheld meters approximately every two weeks adjacent to each continuous water quality monitoring station. These readings are likely not impacted by DO sensor flouling as the meter is only briefly placed in the stream.

It is noted in the data table when a meter was used that did not pass a zero DO check. This indicates the meter might be unable to accurately read 0 mg/L, or may experience a long acclimation period before it can accurately read 0 mg/L. All sondes passed normal calibration prior to being deployed or used for taking discrete readings. The zero DO check is an extra check beyond the typical calibration to evaluate the ability of an instrument to accurately read zero DO, as well as how long it takes to reach zero.

Data determined to be unreliable during QA/QC checks are flagged with accompanying comments. In some cases, partial or suspected fouling may introduce uncertainty without providing sufficient evidence to warrant flagging or exclusion from success criteria calculations. These data are not flagged but include a note in the Comments column indicating the associated uncertainty.

MDNR utilizes all available information in QA/QC of these data including field photographs of the data sondes at each site, concomitant data collected at each site, experience gained from continuous monitoring at other sites in Maryland, and guidance provided by the data sonde manufacturers. MDNR relies on this weight-of-evidence approach combined with best professional judgement when flagging data. This process may be refined over time with more experience in assessing water quality data at the Jabez III monitoring sites. Despite strict adherence to QA/QC procedures for this project, some level of subjectivity in flagging data is unavoidable and may lead to occasional discrepancies among data assessors. All raw data, including those with flags and/or comments, are permanently retained and accessible through MDNR's Eyes on Jabez website for ongoing assessment and future re-evaluation.