MD Dept. of Natural Resources, Chesapeake Bay Mainstem Water Quality Monitoring 2019

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 2019: There was no pycnocline at station CB5.2 and the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth. A very small pycnocline was noted at station CB5.1. Surface conductivity readings changed between the beginning and end of the hydrocasts at stations CB4.4 and CB4.2C. Bottom and below pycnocline samples were collected from a single bottle at station CB2.2. Station CB5.3 and station CB3.3C 0.5 m and 1.0 m water quality readings were taken at the same depth. Station CB3.3C sampling was conducted as the sun set. February 2019: Notes regarding rainfall were logged 11-Feb and 12-Feb. 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. Concern about elevated pH results at station CB2.2 prompted a switch of water quality sondes. The station CB2.2 pH readings on both meters were 9.0 pH units. The data sonde was allowed to sit equilibrating near the bottom for five minutes at station CB2.1. PH readings at station CB1.1 were high and sensor equilibration was protracted. March 2019: Absence of a pycnocline at station CB2.2 led to taking above pycnocline and below pycnocline samples at 1/3 and 2/3 of station total depth. The 0.5 m and 1.0 m water quality readings at stations CB4.3E and CB4.3C were acquired at a single depth. The 18 m and 16 m sonde results at station CB4.3C were double checked. The cabin of RV Kerhin was freshly painted. Nutrient samples collected 11-Mar were not frozen due to equipment issues. On 13-Mar the sampling pump was found to have frozen overnight and was brought into the cabin to defrost enroute to the first station. Meter J was used on 11-Mar and 12-Mar and meter Z was used on 14-Mar. April 2019: The sonde/bottle array touched bottom at station CB5.2 and was repositioned 0.5 m higher in the water column. The array also touched bottom at 24 m at station CB4.1E. Bottom and below pycnocline waters were collected from a single bottle at station CB3.1E. Above and below pycnocline samples were collected at 1/3 and 2/3 of station CB2.2 total depth, respectively. Nutrient samples were not frozen aboard ship 18-April due to problems with the freezer. May 2019: 0.5 m and 1.0 m water quality measurements were taken at the same depth and bottom and below pycnocline samples were collected from the same depth at both station CB3.2 and station CB3.1. Station CB2.2 below and above pycnocline water samples were collected at 1/3 and 2/3 of total depth, respectively. June 2019: The first June mainstem cruise was conducted June 4-6. Station CB5.1W samples were collected June 12 during the Patuxent River survey and 1.0 m and 0.5 m sonde measurements were taken at the same water depth. Upper and lower pycnocline samples at station CB2.2 were collected at 1/3 and 2/3 of total station depth. Sonde readings at 11 m at station CB5.3 were unstable. Station CB4.4 13 m readings were double checked. The 0.5 m and 1.0 m water quality values at station CB4.3E and station CB4.3C were respectively collected at one depth. The second June cruise was conducted June 24-26. Station CB4.1C bottom and below pycnocline sample waters had hydrogen sulfide odors. Station CB5.1 and CB4.2C 0.5 m and 1.0 m water column results were acquired at a single depth at each station. A slight hydrogen sulfide odor was noted in below pycnocline and bottom waters sampled at CB4.1C. The station CB3.1 above pycnocline water sample should have been collected a 3.0 m depth however it was collected at 4.0 m. Three dead fish floated by during sampling operations at station CB3.1. Absence of a pycnocline at station CB2.2 led to taking above pycnocline and below pycnocline samples at 1/3 and 2/3 of station total depth. July 2019: The first July mainstem survey was conducted July 8-10. 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. Scoping was noted at station CB5.1E where the surface and 1.0 m waters samples were collected from the same water depth. Thunderstorms, meter scoping and unstable 12 m sonde readings were observed at station CB4.4. Upper and lower pycnocline samples at station CB2.2 were collected at 1/3 and 2/3 of total station depth because there was no pycnocline. Hydrogen sulfide odors were remarked in station CB4.1C bottom and below pycnocline samples. July 2019: The second July mainstem survey samples were collected July 22-24. Rainfall was heavy at stations CB5.2 and CB5.1. Sampling operations were limited to hydrocasts and comprised solely of water quality sonde readings. Station CB5.1 1-16 m readings were repeated due to concern over meter wheel operations. The station CB4.1 dissolved oxygen reading at 9 m was double checked. Station CB4.3E surface and 1 m sonde measurements were made at the same depth. Log entries stated that rainfall preceded sampling operations at stations CB4.3C, CB4.3W, CB4.1E and CB4.1C. Just one pycnocline break was observed at station CB4.1E. A hydrogen sulfide smell was noted in below pycnocline and bottom water samples collected at station CB4.1C. Dissolved oxygen read less than 0.6 mg/L from 9 m to the bottom at station CB5.3. Station CB5.2 dissolved oxygen readings of less than 0.6 mg/L extended from 7 m to the bottom. Dissolved oxygen less than 0.6 mg/L from extended from 10 m to the bottom. Due to a meter wheel malfunction, station CB5.1 readings from surface to 16 meters were repeated. August 2019: On the first survey (August 5-7), bottom hydrogen sulfide odors were noted at station CB4.4. Similarly, Hydrogen sulfide smells were observed in both below pycnocline and bottom water samples collected at stations CB4.3E, CB4.3C, CB4.2C, CB4.1E, CB4.1C and CB3.3C. The station CB3.3 below pycnocline sample collected at 12 m should have been collected at 11 m. The 5 m and 3 m water quality sonde readings at station CB3.2 were double-checked. Station CB3.2 bottom and below pycnocline sample waters were collected from the same bottle. Station CB2.2 readings at 1 m were checked twice. There was no station CB2.2 pycnocline and the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth. Field log entries for stations CB51, CB4.4, CB4.3E, CB4.3C and CB4.3W noted the presence of afternoon thunderstorms. During the second cruise (August 27- 29), below pycnocline and bottom water samples with hydrogen sulfide odors were noted at stations CB4.2C and CB3.3C. Bottom water hydrogen sulfide odors were observed at stations CB4.3E, CB4.2E, CB4.1E and CB4.1C. September 2019: The drop in dissolved oxygen readings at 12 m at station CB5.1 was double checked. All dissolved oxygen readings at station CB4.4 were double checked. Early morning showers preceded sampling at stations CB4.3E, CB4.3C, CB4.3W, CB4.2W, CB4.2C, CB4.1E, CB4.1W, CB3.3E and CB3.3W. Stations CB4.3E, CB4.3C, CB4.3W, CB4.2W and CB4.2C 0.5 m and 1 m water quality sonde values were measured at the same depth. The sonde/bottle sampling array hit bottom at station CB4.2C and samples were collected at 25 m. At station CB4.1E, the array touched bottom at 23 m and water samples were taken at 22 m. October 2019: Surface dissolved oxygen readings greater than 9 mg/L at stations CB5.1 and CB4.4 prompted opportunistic phytoplankton sample collection at the sites. Station CB4.1E bottom sample water smelled of hydrogen sulfide. The water quality meter was scoping up to 13 m at station CB4.3C. Meter scoping was noted at station CB4.2C. The 17 m above pycnocline sample at station CB4.1C should have been collected at 16 m. November 2019: The water quality sonde used at station CB5.1 ceased operating at 5 m depth and was replaced with a backup instrument. The pH post calibration result of the replacement sonde was outside of acceptable limit of pH 10. Station CB5.1 from 5 m to the surface pH readings were considered questionable. There were no pycnoclines at stations CB5.3, CB5.2, CB4.4 and CB4.1C and the above pycnocline and below pycnocline samples were collected at 1/3 and 2/3 of station total depths. Station CB4.4 water quality sonde values at 0.5 m and 1 m were measured at the same depth. The 2 m above pycnocline sample at station CB4.2C should have been taken at 1 m. Surface and above pycnocline water samples collected at station CB3.2 were taken from the same bottle. Station CB3.1 surface conductivity at the beginning of the hydrocast, changed by the end of the hydrocast. The boat was repositioned in order to collect surface reading and samples at station CB1.1. December 2019: The pH 10 post calibration check result of the water quality sonde used for 11-Dec sampling was outside the acceptable range. All 11-Dec pH readings were considered suspect. Log entries for stations CB3.2, CB3.1, CB2.2, CB2.1 and CB1.1 noted overnight snowfall. There were no pycnoclines at stations CB5.2 and CB5.1 and the above pycnocline and below pycnocline samples were collected at 1/3 and 2/3 for station total depth. Meter scoping occurred at station CB5.2 and 0.5 m and 1 m water quality sonde readings were taken at the same depth. The 0.5 m and 1 m water quality sonde readings at station CB5.2 were taken at the same depth. Station CB3.1 conductivity readings at 6 m were unstable. The sonde/bottle sampling array touched bottom at 10 m at station CB2.2.