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
January 2016: The occurrence of scattered showers the day preceding sampling was noted on field data sheets for stations: WT8.2, WT8.3, WT8.1 and WT7.1. The surface and 1m samples at station ET6.2 came from one water sample. A Cryptomonas flagellate bloom of 62 million cells/L was noted at station XBF1986. There was no pycnocline at stations: ET5.2, EE3.1, EE3.2 and EE2.1 and the above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, respectively. The pH data values acquired at stations: RET2.4 and RET2.2 were considered unreliable.
February 2016: The station ET6.1 Secchi disk depth was measured in the sun instead of in the shade. Station WIW0141 sample water was collected by bucket from the wharf. Due to absence of pycnoclines at stations: EE3.1, EE3.2, EE2.2 and EE1.1, the above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, respectively. Stations: EE2.2 and WT5.1 surface and 1m samples were pulled from water collected at the same depth. Meter scoping and ice on the vessel were noted at station WT5.1. Total depths at stations: ET7.1 and TF1.3 were not recorded. Station ET7.1 samples were collected from the ferry. A plankton sample was collected at station WT3.1 and dissolved oxygen readings were double-checked with a second meter. Snowfall preceding sampling was observed at stations: ET2.3, ET2.1 and ET2.2.
March 2016: Secchi disk depth and total depth were not recorded at station TF1.3 as the water level was deemed “too shallow”. Pycnoclines did not exist at stations: EE3.1 and EE3.2, the above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, respectively. Drizzling morning rain was noted during sampling operations at stations: WT7.1, WT8.1, WT8.2 and WT8.3. At station WIW0141 the ferry was out of service.
April 2016: Above pycnocline and below pycnocline samples at stations: LE2.2, ET5.2, WT5.1, EE1.1, EE2.1, ET4.2, EE3.2 and EE3.1 were collected from one third and two thirds of station water column depth. Station TF1.7 surface and 1m samples were taken from water collected at the same depth. Samples for station TF1.3 were collected from the pier at Patuxent Wetland Park. Secchi disk depth at station TF1.3 was greater than station total water depth. Rainfall preceded sampling at stations: ET2.1 and ET2.2.
May 2016: Dissolved oxygen sensor readings at stations: CB5.1W, LE1.4, LE1.3 and LE1.2 were considered unreliable and sonde D was replaced with sonde J during sampling at station LE1.2. No pycnoclines were observed at stations: EE2.1 and EE3.2. Rain occurred the night before stations EE3.0, EE3.1 and ET6.2 were sampled. StationWIW0141 samples were collected from the ferry. Station TF1.3 samples were collected from the bridge.
June 2016: There was no pycnocline at stations: RET2.4, ET4.2, EE1.1, EE3.2, ET5.2 and EE3.1 and the above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, respectively. Station WIW0141 samples were collected from the ferry.
July 2016: The thermometer used to measure air temperature was in the sun due to loss of an awning during a windstorm. There was no pycnocline at stations: ET5.2, EE2.1 and EE3.1, and the above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, respectively. Dissolved oxygen readings at station WT3.1 were double checked. Thunderstorms occurred the night before samples were collected at station XHH4742.
August 2016: The thermometer used to measure air temperature was in the sun due to loss of an awning during a windstorm. The smell of hydrogen sulfide was noted in water collected from the bottom and below pycnocline bottles at station LE2.2. There was no pycnocline at stations: EE1.1, EE2.1, EE3.1, EE3.2, ET4.2, ET5.2, RET2.4, and the above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, respectively. There were green flocs in the center of the river when station ET3.1 sampling operations were conducted.
September 2016: The 0.1m LI-COR reading at station LE1.1 was not considered reliable. There was no pycnocline at stations: EE1.1, EE2.1, EE3.1, ET3.2, and ET4.2. The above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, respectively.
October 2016: There was no pycnocline at stations: EE1.1, EE3.1, EE3.2, ET3.2 and ET4.2; and the above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, respectively. A station ET3.1 field log note observed that dissolved oxygen readings were high.
November 2016: There was no pycnocline at stations: EE1.1, EE2.1, EE3.1, ET3.2, ET4.2 and Ret4.2. Therefore, the above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, respectively. Meter scoping issues were noted at stations ET3.2 and ET10.1. The bottom sample at station EE3.2 was collected from water at the 25m depth.
December 2016: Rain, during the night preceding sampling, was noted on field log sheets for stations: LE1.1, LE1.2, LE1.3, LE1.4, RET1.1, TF1.3, TF1.4, TF1.7, TF1.6, TF1.5 and WXT0001. Construction around the creek was noted when station PIS0033 was sampled. The above pycnocline and below pycnocline samples were collected from 1/3 and 2/3 of total water column depths, due to no pycnocline, at stations: EE1.1, EE2.1, EE3.1, EE3.2, ET5.2, LE2.2 and RET2.4. The pH sensor was slow to equilibrate at station ET6.1. The water level at Station ET4.1 was very shallow.