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.
January 2021: A pycnocline was not detected at stations 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. Fog was noted during sampling at stations RET2.1, RET2.2, RET2.4, TF2.1, TF2.4, and XFB1986. During sampling at station TRQ0146, skim ice was present upstream. The boat ramp at station XDJ9007 was under construction. An EXO meter was used to collect readings at station LE2.3.
February 2021: Samples at stations EE1.1, EE3.1, EE3.2, ET4.2, and LE2.3 were collected at 1/3 and 2/3 depths due to the absence of a pycnocline. It rained the night before sampling at stations TF1.0, TF1.2, TF1.3, TF1.4, and WXT0001, and the meter used at these stations post-calibrated out of range (high) for specific conductance and pH. The surface and above pycnocline samples at station RET2.4 were collected at the same depth. A barge went down river just prior to sampling at station WIW0141. An EXO meter was used to collect readings at station LE2.3.
March 2021: Due to the absence of pycnoclines at stations EE2.1, EE3.1, EE3.2, and LE2.3, above and below pycnocline samples were collected from 1/3 and 2/3 of total station water column depths. Station ET4.1 was sampled during an extreme low tide. Rain drizzle occurred the morning before sampling at station LE2.3. An EXO meter was used to collect readings at station LE2.3.
April 2021: Stations EE2.1, EE3.1, EE3.2, ET5.2, LE2.3, and RET2.4 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. It rained the night before sampling at station ET10.1. Oily spots were observed on the water surface at station PIS0033. The Secchi disk depth measurement at station TF1.3 was greater than the total depth. An EXO meter was used to collect readings at station LE2.3.
May 2021: At station EE1.1, the bottom and below pycnocline samples were collected at the same depth. A pycnocline was not detected at stations EE2.1, EE3.1, EE3.2, ET4.2, and ET5.2. Above pycnocline and below pycnocline samples at these stations were collected at 1/3 and 2/3 depths, respectively. A fisherman was present at the end of the pier during sampling at station ET6.1. Samples for station ET7.1 were collected while following a barge. Bridge work was noted at station TRQ0088. Station WIW0141 was sampled after a tow boat and barge had passed. An EXO meter was used to collect readings at station LE2.3.
June 2021: Stations EE1.1, EE2.1, EE3.2, ET4.2, LE2.3, and WT5.1 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. Station RET2.4 had a weak pycnocline. A thin layer of green clumps was observed on the water surface at station ET3.1. A strong ebb tide and a milky film on the water surface were noted at station ET4.1.
July 2021: 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, and RET2.4. Hazy conditions were noted at stations EE2.2, LE1.2, LE1.3, LE1.4, LE2.3, RET1.1, TF1.5, TF1.6, and TF1.7. A strong ebb current was present during sampling at station ET10.1. The Secchi disk depth measurement at station TF1.3 was greater than the total depth.
August 2021: The total depth reading at station BXK0031 was taken at a slight angle due to strong currents. Hydrogen sulfide odor was detected with the bottom and below pycnocline samples at station EE1.1. Stations EE2.1, EE3.1, ET5.2, LE2.2, LE2.3, and RET2.4 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. The meter used at stations ET10.1, MNK0146, and POK0087 post-calibrated high for specific conductance. The dissolved oxygen readings at station ET9.1 were double-checked, and the surface dissolved oxygen reading at RET2.1 was checked with meter Q. Overnight rain was noted at stations LE1.1, RET1.1, TF1.0, TF1.2, TF1.3, TF1.4, TF1.5, TF1.6, TF1.7, WT1.1, WT2.1, WT3.1, WT4.1, and WXT0001.
September 2021: Morning rain fell the day of sampling at stations LE1.1, RET1.1, TF1.5, TF1.6, and TF1.7. A pycnocline was not detected at stations EE1.1, EE3.1, EE3.2, ET4.2, ET5.2, and LE2.3; therefore, samples at these stations were collected at 1/3 and 2/3 depths. Fog and/or haze were reported at stations EE2.1 and EE2.2. EXO meter B was used to collect readings at station LE2.2. Readings at stations MAT0078 and PIS0033 were collected using EXO1 meter A. The surface reading for specific conductance changed during sampling at RET2.4.
October 2021: The bottom and below pycnocline samples at station EE2.1 were collected at the same depth. Stations EE3.1, EE3.2, ET5.2, and RET2.4 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. Morning showers were noted at stations EE1.1 and ET4.2, and the readings at both stations were taken with an EXO1 meter. The meter used at stations CCM0069, ET3.1, ET4.1, ET6.1, TRQ0146, WIW0141, and XDJ9007 did not undergo a post-calibration check after sampling. The Secchi disk depth measurement at station TF1.3 was greater than the total depth.
November 2021: A pycnocline was not detected at stations EE1.1, EE2.1, EE3.1, ET5.2, LE2.3, and RET2.4. Above and below pycnocline samples at these stations were collected at 1/3 and 2/3 depths, respectively. At stations MAT0078 and PIS0033, flow in the creek was described as low.
December 2021: A pycnocline did not exist at stations EE2.1, EE3.1, EE3.2, ET4.2, ET5.2, LE2.2, LE2.3, and RET2.4, and the above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total station water column depth. The walkway on the bridge at station ET10.1 was being replaced. At station TF1.3, the Secchi disk depth measurement was greater than the total depth. At station LE1.3, the Secchi disk depth measurement was greater than 3 meters.
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