QUALITY ASSURANCE/QUALITY CONTROL
Maryland Department of Natural Resources followed specific procedures to ensure that the Tributary component of the Chesapeake Bay Water Quality Monitoring Program design was properly implemented and managed with sufficient accuracy, precision and detection limits. Accuracy (closeness to the true value) of collected data was controlled and assured by proper use, calibration and maintenance of both field and laboratory equipment for the measurement of physical and chemical parameters.
The procedures used to control and assure the accuracy of field measurements involved the calibration of field instruments, the verification of calibrations, and equipment maintenance. Most of the details of how data acquired with YSI sondes and Hydrolab sondes were quality assured and quality controlled are described in the process description elements in the Lineage portion of this metadata record.
Daily quality control checks which included the running of blanks and standards were used to control and assure laboratory accuracy.
Accuracy of Chesapeake Biological Laboratory, Nutrient Analytical Services Laboratory (CBL NASL) results was also assessed through DNR's participation in the Chesapeake Bay Coordinated Split Sample Program (CSSP) a split sampling program in which five laboratories involved in Chesapeake Bay monitoring analyze the coordinated split samples. CSSP was established in June 1989 to establish a measure of comparability between sampling and analytical operations for water quality monitoring throughout the Chesapeake Bay and its tributaries. DNR followed the protocols in the Chesapeake Bay Coordinated Split Sample Program Implementation Guidelines (EPA 1991) and its revisions. Split samples were collected quarterly. Results were analyzed by appropriate statistical methods to determine if results differed significantly among labs. If a difference occurred, discussions began regarding techniques and potential methods changes to resolve discrepancies.
ADDITIONAL COMMENTS
In September 2021, the Baltimore Gas and Electric company began work rebuilding a transmission line that runs across the Bush River in Harford County, Maryland. The project involves the replacement of three double circuit steel lattice towers (one on each shore and one located within Bush River) and four single circuit wood H-frames (two on each side of the river) with nine steel galvanized monopoles. MD DNR tributary monitoring station WT1.1 is located on the Bush River within 1000ft downstream of the project, and water quality at that station may be impacted by the ongoing construction activities. Of particular note in 2022, the existing transmission line cables were removed during the period June 27 - July 8. Due to the nature of the cables, each cable dragged along the river bottom for approximately 10-15 minutes during the removal process.
January 2022: A pycnocline was not detected at stations EE1.1, EE2.1, EE3.1, EE3.2, and ET5.2. Above pycnocline and below pycnocline samples at these stations were collected at 1/3 and 2/3 depths, respectively. The Secchi disk depth measurement at station TF1.3 was greater than the total depth. The total depth was greater than 4.0 meters at station TRQ0088. At station LE2.2, specific conductance at the surface changed during sampling. Rain and snow fell on 16-Jan, several days before sampling at stations MAT0078 and PIS0033. The bridge was under construction at station CCM0069, and skim ice was reported at the site. At station TRQ0146, the water was reported as 90% frozen upstream, and 50% frozen downstream.
February 2022: Afternoon rain showers occurred the day before sampling at stations EE2.1 and EE2.2. Samples at stations EE3.2, ET5.2, and LE2.3 were collected at 1/3 and 2/3 depths due to the absence of a pycnocline. At station ET4.2, the bottom and below pycnocline samples were collected at the same depth. The Secchi disk depth measurement at station TF1.3 was greater than the total depth. The specific conductance and pH measurements at station TF2.4 were rechecked and confirmed. Frozen precipitation fell the night before sampling at station WT5.1. Skim ice was reported at station WT6.1.
March 2022: Due to the absence of pycnoclines at stations EE1.1, EE2.1, EE3.1, EE3.2, and ET5.2, above and below pycnocline samples were collected from 1/3 and 2/3 of total station water column depths. The pier was being removed during sampling at station CCM0069. The surface conductivity at station LE2.3 changed by 800 µS/cm during sampling. The Secchi disk depth measurement at station TF1.3 was greater than the total depth. Rain earlier in the day was reported at stations TRQ0146, WT1.1, WT2.1, and WT3.1.
April 2022: Stations EE2.1, EE3.2, and LE2.3 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. Morning rain was reported at stations LE1.1 and RET1.1. At station LE2.2, the surface and above pycnocline samples were collected at the same depth. A cargo ship passed while sampling at station WT5.1. The profile readings at station XAK7810 were double-checked.
May 2022: A pycnocline was not detected at stations EE3.1, EE3.2, and ET5.2. Above pycnocline and below pycnocline samples at these stations were collected at 1/3 and 2/3 depths, respectively. High water was reported at stations CCM0069, TRQ0088, and TRQ0146. Heavy rain occurred in the days prior to sampling at stations MAT0078 and PIS0033, and the water at these stations appeared muddy. Severe thunderstorms were reported at station ET5.2, and overnight thunderstorms were noted at station LE2.3. At station WIW0141, the total depth was greater than 4m, and the ferry was closed due to flooding. Dissolved oxygen and pH readings at stations BXK0031 and MAT0078, respectively, were double-checked with a second meter.
June 2022: Stations EE2.1, EE3.1, EE3.2, and ET5.2 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. At station LE2.3, the surface conductivity changed during sampling. Scattered showers occurred during the day and continued through the night on the date prior to sampling at stations TF1.3, TF1.4, and WXT0001. Station EE1.1 was sampled during very rough seas.
July 2022: Due to the absence of a pycnocline, samples were collected at 1/3 and 2/3 depths at the following stations: EE1.1, EE2.1, EE3.1, EE3.2, ET4.2, ET5.2, LE2.3, and RET2.4. The meter used at stations EE3.3, ET5.1, LE2.2, WT5.1, and XAK7810 was unable to be post-calibrated for dissolved oxygen.
August 2022: A strong hydrogen sulfide odor was detected with the bottom and below pycnocline samples at station LE2.2. Stations EE1.1, EE2.1, EE3.1, EE3.2, ET4.2, and ET5.2 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. Scattered showers occurred the night before sampling at stations TF1.2, TF1.3, TF1.4, and WXT0001. The pH readings at station WT4.1 were confirmed with a second meter.
September 2022: A pycnocline was not detected at stations EE3.1, EE3.2, ET4.2, ET5.2, and RET2.4; therefore, samples at these stations were collected at 1/3 and 2/3 depths. Fog was reported at station RET2.4. At station WT8.1, a sewage truck spill occurred the day before sampling and was followed by heavy rain.
October 2022: A barge was on top of the sample site at station WT1.1. Stations ET4.2, ET5.2, EE1.1, EE2.1, EE3.1, EE3.2, LE2.3, and RET2.4 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. Bridge construction was ongoing at station RET2.4. The readings at station WT4.1 were confirmed with a second meter. The Secchi disk depth measurement at station TF1.3 was greater than the total depth.
November 2022: A pycnocline was not detected at stations ET5.2, EE1.1, EE2.1, EE3.1, EE3.2, LE2.3, and RET2.4. Above and below pycnocline samples at these stations were collected at 1/3 and 2/3 depths, respectively. Because the surface conductivity changed during sampling, station LE2.2 was sampled as if no pycnocline was present, with samples collected at 1/3 and 2/3 depths. At station RET2.4, bridge construction was complete and demolition work on the old bridge was not active on the sample date. The Secchi disk depth measurement at station TF1.3 was greater than the total depth.
December 2022: Stations ET4.2, ET5.2, EE2.1, EE3.1, EE3.2, and LE2.3 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. At station TRQ0146, upstream coverage of skim ice was estimated as 50%, with some ice downstream. The Secchi disk depth measurement at station TF1.3 was greater than the total depth. At station RET2.4, the Rt. 301 bridge construction was complete and demolition of the old bridge was active on the sample date.