MD Dept. of Natural Resources, Chesapeake Bay Mainstem Water Quality Monitoring 2021

QUALITY ASSURANCE/QUALITY CONTROL. Maryland Department of Natural Resources followed specific procedures to ensure that the Mainstem 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 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 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 January 2021: Scoping is a term used to describe situations when strong currents and or winds make it difficult to maintain the water quality data sonde at a depth long enough for readings to stabilize. Meter scoping was noted at stations CB4.4, CB5.1, CB5.2, and CB5.3. There was no pycnocline at station CB2.2, and above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth. Conductivity readings at 0.5 m and 12 m depths were unstable at stations CB4.4 and CB5.3, respectively. Surface conductivity readings changed between the beginning and end of the hydrocasts at stations CB2.2, CB3.2 and CB5.3. The bottom could not be reached at CB5.1. The pump hose used for sample collection at CB3.2 was frozen. February 2021: Meter scoping was noted at stations CB3.3C, CB4.4, CB5.1, CB5.2, and CB5.3. There was no pycnocline at stations CB2.2 and CB4.1C, so above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth. March 2021: Pycnoclines were not evident at stations CB4.4, CB5.1 and CB5.2. Above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth at these stations. Sampling was conducted in the fog at station CB3.3C. The 6 m dissolved oxygen readings at station CB3.1 were double-checked. Conductivity readings were unstable at the surface for station CB3.2 and at 0.5-2 m depth for station CB4.1C. April 2021: Thin clouds were reported at station CB4.1E, and the station’s readings were double-checked. A ship passed when sampling at station CB4.2C. Surface conductivity readings changed between the beginning and end of the hydrocast at station CB4.1C. May 2021: Pycnoclines were not evident at stations CB5.1, CB5.2 and CB5.3. Above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth at CB5.1, CB5.2 and CB5.3. Four gates of the Conowingo Dam were open at station CB1.1. June 2021: The first June mainstem survey was conducted June 1-3. Log entries stated that rainfall preceded sampling operations at stations CB2.1, CB3.1 and CB3.2. There was no pycnocline at station CB2.2, and above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth. The second June mainstem survey was conducted June 21-24. Station CB4.1C bottom and below pycnocline sample waters had hydrogen sulfide odors. A slight hydrogen sulfide odor was noted in the bottom water sample collected at station CB4.1E. Surface and above pycnocline water samples collected at station CB3.1 were taken from the same bottle. The surface conductivity reading was very unstable at station CB3.2. July 2021: The first July mainstem cruise was conducted July 6-8, and hazy conditions were reported during this cruise. An odor of hydrogen sulfide was observed in bottom and below pycnocline water samples collected at stations CB3.3C, CB4.1C, CB4.1E, CB4.2C and CB4.3C. A slight hydrogen sulfide odor was also noted in bottom sample water at stations CB4.4 and CB5.1. There was no pycnocline at stations CB2.2 and CB4.3E, so above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth. Water column measurements only (no pigment or nutrient samples) were collected during the second July (14-15) mainstem survey. Hazy conditions were reported at stations CB1.1 and CB5.1W. August 2021: The first August mainstem cruise was conducted August 2-4. Station CB4.3E bottom and below pycnocline sample waters had a hydrogen sulfide odor. A hydrogen sulfide odor was noted in bottom water samples collected at stations CB4.1C, CB4.1E and CB4.2C. The dissolved oxygen reading at 10 m depth at station CB4.3C was double-checked. The 1 m water quality sonde readings at station CB4.2E were double-checked. A ship passed when sampling at stations CB3.2 and CB4.4. The second August mainstem survey was conducted August 23-25, and hazy conditions were reported during this cruise. The sonde/bottle sampling array touched bottom at station CB5.3. A hydrogen sulfide odor was noted in bottom sample water at stations CB4.2C and CB4.3C. There was no pycnocline at station CB2.2, so above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth. Bottom and below pycnocline samples were collected from a single bottle at station CB3.2. Hurricane/Tropical Storm Henri passed the East Coast on August 20-22 with heavy rainfall in the northern portion of the Chesapeake Bay watershed. September 2021: Remnants of Hurricane Ida passed on September 2, prompting the opening of several gates at Conowingo Dam. Hazy conditions were reported during the September cruise. The water quality meter was scoping near the bottom at stations CB5.1 and CB5.3. A pycnocline was not evident at stations CB2.2 and CB5.3, therefore the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. The 5 m water quality sonde readings at station CB3.2 were double-checked and the dissolved oxygen reading at 2 m depth at station CB5.1 was also double-checked. October 2021: A pycnocline was not evident at station CB2.2, therefore the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth. Drizzled while at station CB5.3, and thin clouds were observed at station CB4.2C. The dissolved oxygen reading at 13 m depth at station CB5.2 was double-checked. November 2021: Meter scoping was noted at stations CB4.4, CB5.1, CB5.2, and CB5.3. There was no pycnocline at station CB2.2, so above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth. The 0.5 m and 1 m conductivity readings at station CB3.2 were double-checked. December 2021: Pycnoclines were not evident at stations CB4.4, CB5.1, CB5.2, CB5.3, CB4.2C and CB4.1C. Therefore, the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. Surface conductivity readings changed between the beginning and end of the hydrocast at station CB3.2.