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. This work was completed on or before April 2023.
January 2023: 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. Overnight showers occurred prior to sampling station LE2.3. The surface conductivity at station RET2.4 changed during sampling.
February 2023: Rain earlier in the day was noted at station EE2.1. Samples at stations EE2.2, EE3.1, EE3.2, ET4.2, and ET5.2 were collected at 1/3 and 2/3 depths due to the absence of a pycnocline. Demolition of the old bridge at station RET2.4 was active on the sample date.
March 2023: Due to the absence of a pycnocline at stations 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. Specific conductance changed during sampling at station ET5.1. The Secchi disk depth measurement at station TF1.3 was greater than the total depth. Dredging was reported at station ET2.3, downstream of the Elk River.
April 2023: Stations EE1.1, EE2.1, 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. The Secchi disk depth measurement at station TF1.3 was greater than the total depth. The meter used at stations LE1.1, RET1.1, TF1.5, TF1.6, and TF1.7 failed post-calibration for pH, however data appears normal.
May 2023: Scattered showers were reported earlier in the day at station LE2.3, and drizzle was reported at station RET2.4. A pycnocline was not detected at stations LE2.3, 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 total depth was greater than 2.0 meters at station TRQ0088, and a strong current was detected at this station. Dissolved oxygen readings at station WT7.1 were double-checked with a second meter. The Secchi disk depth measurement at station XGG8251 was greater than the total depth.
June 2023: Hazy conditions due to regional wildfires were reported at stations BXK0031, ET4.1, ET5.1, ET5.2, WT1.1, WT2.1, WT3.1, WT4.1, WT5.1, WT6.1, WT7.1, and WT8.2. Weather conditions at station POK0087 were gusty, and hail was recorded. Stations EE2.1, 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. The meter used at stations WT6.1 and WT7.1 was unable to be post-calibrated for pH, but data appear normal.
July 2023: 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. Specific conductance changed during sampling at station EE3.1. Hazy conditions were reported at stations TF1.0 and TF1.2. The meter was unable to be post-calibrated for pH for the following stations: RET2.4, RET2.2, RET2.1, TF2.4, MAT0016, TF2.3, TF2.2, TF2.1, and XFB1986, but the data appear normal.
August 2023: Stations LE2.2, LE2.3, EE1.1, EE2.1, EE3.1, EE3.2, ET4.2, ET5.2, and RET2.4 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. The conductivity reading at 3.0 meters at LE1.2 was reported to be questionable. At station LE1.3 the pH value at 1.0 meters was also listed to be questionable and was flagged, but data appears normal.
September 2023: Morning rain was documented for stations LE1.2, LE1.3, and RET2.4, as well as a morning thunderstorm at station LE2.2. Overnight showers were recorded for RET2.1 and TF2.4. A heavy current was reported at station RET2.4. A pycnocline was not detected at stations EE2.1, EE3.2, and ET5.2; therefore, samples at these stations were collected at 1/3 and 2/3 depths. Unstable specific conductance readings were reported at stations RET2.4 and TF2.4.
October 2023: Stations EE3.1, EE3.2, ET4.2, ET5.2, LE2.3, and RET2.4 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. The Secchi disk depth measurement at station TF1.3 was greater than the total depth. Dissolved oxygen values were noted to be high at station XFB1986, possibly indicating an algae bloom.
November 2023: A pycnocline was not detected at stations EE1.1, EE2.1, EE3.1, EE3.2, ET4.2, ET5.2, LE2.2, and LE2.3. Above and below pycnocline samples at these stations were collected at 1/3 and 2/3 depths, respectively. Station TF2.1 was sampled in deep water.
December 2023: The Potomac River sampling cruise was rescheduled from 11-Dec to 12-Dec due to hazardous winter storm conditions. Over four inches of rain fell over southern Maryland 10-Dec to 11-Dec, with two inches of rapid snow melt. Stations EE1.1, EE2.1, EE3.1, EE3.2, ET4.2, and LE2.3 were sampled at 1/3 and 2/3 depths due to the absence of a pycnocline. Surface specific conductance changed during sampling at station ET4.2.