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) and Maryland Department of Health and Mental Hygiene (DHMH) 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. The Chesapeake Bay Program Data Integrity Workgroup (formerly AMQAW) oversees the CSSP. 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.
January 2017: The station POT1596 sample was collected in a sediment plume that extended 75 feet from shore. Rain fell two days before sampling at stations CB1.0 and DER0015. Morning rain preceded sampling at stations GEO0009 and NBP0461. Lots of trash, from rainfall on the day preceding sampling, was noted at station ANA0082. There was streamside ice at stations ANT0366 and CON0180. Jumpy pH readings were noted at stations GWN0115, NPA0165 and PAT0285. High water levels were observed at stations: GEO0009, NBP0103, NBP0461, NBP0534, NBP0689, POT2766, SAV0000, TOW0030 and WIL0013. The Secchi disk measurement at station XGG8251 was greater than the station total depth. Waters at stations GEO0009 SAV0000, TOW0030, and WIL0013 were clear. Waters at stations POT2036, NBP0103, NBP0609 and NBP0534 were slightly murky.
February 2017: Rainfall and snowmelt, two days preceding sampling, were noted at stations: GEO0009, NBP0326, NBP0461, NBP0534, NBP0689 and SAV0000. A Jersey wall on the new bridge at station NBP0326 complicated sample collection. High water levels were noted at stations POT2766 and POT2386. Water at station POT2386 was murky.
March 2017: The water at station GEO0009 was clearer than normal. Dead carp were present in the water and on the bank at the time station POT1830 samples were collected. Conductivity results at station MON0269 were questionable and a switch was made to meter P. Conductivity measurements obtained using meter T at stations BPC0035 and MON0528 were deemed bad and censored in the data set. When station PXT0809 was sampled, demolition was occurring upstream and water was discharging above the site. At station POT2766, the water level was high and the beach area was flooded. Snowmelt and rainfall occurred the weekend before sampling at stations GEO0009, LYO0004, NBP0689, TOW0030, WIL0013 and YOU0925. Scattered showers fell the day prior to sample collection at stations: CB1.0, DER0015, GUN0258 and GUN0476. It rained the night before the following stations were sampled: ANT0044, BPC0035, CAC0031, CAC0148, LYO0004, MON0020, MON0155, MON0269, MON0528, POT1471, POT1472, POT1595, POT1596, POT1830, SEN0008 and YOU1139.
April 2017: When samples were collected at station BDK0000, lots of algae, possibly filamentous, were noted. The Secchi disk depth measurement at station XGG8251 exceeded the total water depth at the site. Station ANT0203 waters were slightly murky. Debris blocked the right edge of the stream when station CON0005 was sampled. Construction was ongoing when stations PAT0176 and PXT0809 were sampled. Didymo was not visible at station SAV0000. High water levels were noted at stations: CON0180, LYO0004, NBP0023, NBP0103, NBP0461, NBP0534, NBP0689, POT2386, TOW0030, YOU0925 and YOU1139. Heavy rain and snow melt occurred during the week preceding sampling at stations LYO0004, NBP0023, NBP0103 and NBP0461. Heavy rain upstream occurred the day prior to sample collection at station POT2386. Overnight rain showers occurred prior to sampling at station ET5.0.
May 2017: Water dripped off the bridge into the bucket as it was being collected from the bank at station ANT0366. Didymo was not visible at station SAV0000. There was a large pile of debris upstream of the station CON0005 bridge. Station NBP0534 waters were clear. Ending sample time at stations POT1595 and SEN0008 were estimated. Water levels at stations POT02766, NBP0461 and NBP0534 were very high. High water levels were noted at stations BDK0000, CON0180, GEO0009, LYO0004, NBP0023, NBP0103, NBP0689 and WIL0013. Rains occurred during the week before samples were collected at stations CAS0479, NBP0103, NBP0689 and WIL0013.
June 2017: Didymo was not visible at station SAV0000. Submerged aquatic vegetation was present at station TOW0030. Scattered drizzle preceded sampling at stations CAC0031, MON0020, POT1471, POT1472, POT1595, POT1596 andSEN0008.
July 2017: Braddock Run waters were unusually clear when samples were collected at station BDK0000. Didymo was not visible at station SAV0000. Heavy rain fell over the weekend prior to sampling at stations CAS0479 and YOU0925. The creek was high and muddy at station LYO0004. There were heavy downpours the day before sample collections at stations LYO0004 and YOU1139. Light rain fell the night before and steadier rain fell in the morning preceding station ET5.0 sampling. It rained during the morning station JON0184 was sampled. Scattered showers fell during sampling operations at stations CAC0031, MON0020, MON0155, POT1471, POT1472, POT1595, POT1596, PXT0809 and SEN0008.
October 2017: Station GEO0009 water was dark orange. The water at station PIS0033 appeared stagnant. At station CON0005, no algae were visible from the bridge and the water and creek bed were clear. Algae, possibly filamentous, covered station CON0180 rocks and the water was very clear. Station NBP0534 waters were slightly murky. Water at station SAV0000 was murky. Construction was on-going at station PXT0809. Dissolved oxygen was checked with meter Y at station SEN0008. USGS staff members were on site when samples were collected at station ET5.0. The water levels at stations CB1.0, GUN0125 and GUN0115 were very low. The river levels were low at stations JON0184, MON0020, POT1472, POT1595, POT1596 and SEN0008. Rain fell the over the weekend before station WIL0013 was sampled. Morning rain preceded sampling at stations NBP0326 and YOU1139. Heavy rain, prior to station NBP0534 sample collection, was noted. Rain ceased as station GEO0009 sampling began.
November 2017: One Conowingo Dam flow gate was open when station CB1.0 waters were sampled. Station YOU0925 was sampled during dam release and the gage heights were fluctuating. The left side of the station CON0005 bridge was blocked by debris from a recent storm. The water level at station POT2386 was higher than normal. There was evidence of Braddock Run waters, on the right eastern shore, when station WIL0013 samples were collected. Didymo was not visible at station SAV0000. The Secchi disk measurement at station XGG8251 exceeded station total depth.
December 2017: Debris and logs blocked the entire right Eastern shore when station CON0005 samples were collected. When station WIL0013 was sampled, the effect of Braddock Creek waters was evident along the Eastern shore. Staff from the USGS were conducting flow surveys upstream when Station PAT0285 was sampled. Station SEN0008 dissolved oxygen results were checked with meter J. The reaction time of the water quality sonde pH sensor was observed to be slow at stations PXT0972 and NBP0326. Didymo covered approximately 70 percent of the station SAV0000 sampling location water bottom. Rain fell the night before sampling at the following stations: CAC0031, MON0020, MON0155, POT1471, POT1472, POT1595, POT1596 and SEN0008.