Spatial Data Set Title:
Shallow Water Monitoring Program – Continuous Monitoring
Abstract:
This monitoring project consists of 7 CBP segments (YRKPH, YRKMH, MPNOH, MPNTF, PMKOH, PMKTF, PIAMH) which are monitored continuously using YSI 6600 (or YSI 6000) data sondes, which record water quality parameters once every 15 minutes over a one to two week deployment at which time they are replaced to maintain the continuity of the data set. There are a total of 11 stations; two in YRKPH, two in YRKMH, 3 in the PIAMH and one each in the MPNOH, MPNTF, PMKOH, and PMKTF segments.
Purpose:
Monitoring water quality within Chesapeake Bay Tributaries.
Originator:
VIMS - College of W&M
Time Span:
01 Jan – 31 Dec, 2004
Progress:
Complete
Maintenance/Update Frequency:
As Needed
Access Constraints:
Not Applicable
Use Constraints:
Not Applicable
Subject Keywords:
Monitoring, Nutrients, Salinity, Tributaries, Water, Water Quality
Other Keywords:
Turbidity, Chlorophyll, Fluorescence, DO Profiles
Place Keywords:
York River, Mattaponi River, Pamunkey River, Piankatank River, Dragon Run, Virginia (VA)
Bounding Box:
W -77.21373 E -76.24777 N 37.80638 S 37.21366
Distribution Contact:
Joy Austin
Laboratory Manager
VIMS - College of W&M
PO Box 1346
Rt 1208 Greate Rd
Gloucester Point, VA 23062
804-684-7307
Distribution Liability:
The user of this database should carefully review all pertinent documentation. All water quality data are submitted or translated to the format described in the Water Quality Database Design and Data Dictionary.
Target Audience:
Scientists
Geographic Description:
York, Mattaponi, Pamunkey, and Piankatank Rivers, Virginia, USA
Attribute Accuracy Report:
All data generated by the laboratory is subjected to QA/QC protocol and peer review. Instrument maintenance is performed and recorded in instrument manuals.
Laboratory QC: Sensor specifications, range of measurements, units, resolution, and
accuracy:
YSI 6000/6600 datalogger
Variable Range of Measurements Resolution Accuracy
Date 1-12, 1-31, 00-99 (Mo,Day,Yr) 1 mo, 1 day, 1 yr NA
Time 0-24, 0-60, 0-60 (Hr,Min,Sec) 1 hr, 1 min, 1 s NA
Temp -5 to 45 (c) 0.01 C +/-0.15C
Sp COND 0-100(mS/cm) 0.01mS/cm +/-0.5% Of
reading + 0.001mS/Cm
Salinity 0-70 Parts per thousand (ppt) 0.01 ppt +/- 1% of Reading or 0.1
ppt, (whichever is greater)
DO 0-200 (% air saturation) 0.1% @air sat +/-2% @air Saturation
DO 200-500 (% air saturation 0.1% @ air sat +/- 6% @ Saturation
DO 0-20 (mg/l) 0.01 mg/l +/- 0.2mg/l
DO 20-50 (mg/l) 0.01 mg/l +/- 0.6mg/l
Depth (shallow) 0-9.1 (m) 0.001m +/- 0.018m
PH 2-14 units 0.01 units +/- 0.2units
Turb 0-1000 NTU 0.1 NTU +/- 5% of
Reading or 2 NTU (whichever is greater)
Logical Consistency Report:
None
Completeness Report:
All deployment schedules were adhered to. Any other gaps in the data, due to sonde or probe malfunction are noted in the PROBLEM column, where available, or in the COMMENTS column if it is not.
Horizontal and Vertical Accuracy Report:
A WAAS enabled Garmin GPSMAP 168 using NAD83 was used to determine position in associated with each station location. During 2004, Trimble Surveying Equipment was used to determine a more accurate set of coordinates for each of the stations. The following was taken from Appendix D of the Quality Assurance Project Plan for Shallow Water Monitoring For the Period: April 1, 2004 through April 1, 2006 and will explain any differences in coordinates between the years of the monitoring program.
The original coordinates that were listed in the initial Quality Assurance document (see: Quality Assurance Project Plan for Shallow Water Monitoring For the Period: April 1, 2003 through December 31, 2003) were projected site coordinates that came from a number of sources. The coordinates from Clay bank, Taskinas Creek, and Sweethall Marsh were taken at the already established NERRS fixed stations with a handheld GPS unit. The coordinates for Yorktown and Gloucester Point were taken in the planned locations of those two stations with a handheld GPS. And the coordinates for Muddy Point, Walkerton, and White House were the DEQ tidal tributary station coordinates, as we were going to try to place our fixes stations in the same area as the monthly samples were taken. Once all the above stations were actually established, a second set of coordinates were taken for each with a boat mounted Garmin GPSMap 168. It was this set of coordinates that were used to assign the Cheasapeake Bay Program station identifiers. There has been some confusion as to the location of the stations because the first set of coordinates got left in the QAPP document instead of being replaced with the actual coordinates that were taken at each station and used to develop the station IDs. This appendix is to provide clarification on this issue. To further complicate the matter, 4 stations have had to be moved or repaired, and a third set of coordinates has been generated using Trimble surveying equipment that is highly accurate. We wanted to provide this data but in conjunction with the two other coordinate sets listed above it has further confused the issue. The 2005 QAPP document, to which this appendix is attached, lists the original coordinates from the established stations during the first year, as well as the more accurate Trimble coordinates.
Station / 2003 QAPP / Garmin GPSMap 168 / Trimble SurveryLatitude / Longitude / Latitude / Longitude / Latitude / Longitude
Gloucester Point / 37.24889 / 76.49528 / 37.24828 / 76.49652 / 37.24840 / 76.49670
Yorktown / 37.24432 / 76.52430 / 37.24432 / 76.52430 / 37.24424 / 76.52466
Clay Bank / 37.34767 / 76.61042 / 37.34708 / 76.61165 / 37.34855 / 76.61123
Taskinas Creek / 37.41525 / 76.71439 / 37.41742 / 76.70888 / 37.41497 / 76.71441
Muddy Point / 37.57139 / 76.79119 / 37.57552 / 76.79768 / 37.57550 / 76.79756
Walkerton / 37.72294 / 77.02536 / 37.72288 / 77.01958 / 37.72297 / 77.02029
Sweethall Marsh / 37.57136 / 76.88411 / 37.57128 / 76.88405 / 37.57138 / 76.88424
White House / 37.58014 / 77.02097 / 37.57678 / 77.02345 / - / -
The above table contains all three sets of coordinates so that they can be compared. The coordinates from the GPSMap 168 and the Trimble Survery GPS were converted to UTM Eastings and Northings which are in meters. It is then possible to calculate the difference in meters between the original station coordinates and Trimble coordinates, this is done by taking the difference between the two x coordinates squared plus the difference between the two y coordinates squared and taking their square root (difference = square root((x1-x2)^2 + (y1-y2)^2). The table below summarizes those differences and gives information on any movement of the station in the last year.
Station / CBP ID vs Survey (meters) / Station Moved/RebuiltGloucester Point / 20.59 / No, has never been moved
Yorktown / 33.06 / Yes, completely destroyed by hurricane and rebuilt
Clay Bank / 167.04 / Yes, moved to slightly deeper water
Taskinas Creek / No, has never been moved
Muddy Point / 10.77 / No, has never been moved
Walkerton / 63.34 / Yes, post ice damage, recreated in original footprint
Sweethall Marsh / 16.57 / No, never been moved, affixed to a permanent dock
White House / No Trimble Survey yet / Yes, approx 0.5m inshore post ice damage
It is important to notice that there are some stations that moved between the time when the two sets of coordinates were taken and some that did not, but ALL stations show a difference between coordinates. Looking at these differences there are a number of things to consider (differences are in meters). First of all the coordinates that make up the CBP IDs were taken with the GPSMap 168. This GPS has an accuracy of <15 meters in normal mode and <3 meters with the WAAS setting enabled. The Survey coordinates were taken with a highly accurate Trimble surveying GPS unit for which the accuracy is more on the order of millimeters. This could account for some of the difference we are seeing. I think that the important thing to notice is even those stations that did not move, including those affixed to a dock structure that has certainly not moved, show a difference between the two sets of coordinates (between 10.77 and 20.59 meters). I cannot explain this difference except that with varying satellite coverage and different GPS accuracies there are differences.
Of those stations of concern that have moved or been rebuilt (Yorktown, Clay Bank, Walkerton, and White House) none are located near a creek outflow that might influence them. Looking at the profiles done at these fixed stations, especially Clay Bank which was moved slightly deeper in order to keep the sonde from regularly being exposed on low tide, there does not seem to be any difference in profiles before and after the move for both salinity and DO. So the movement does not seem to have greatly changed the conditions of the stations.
Clay Bank - According to the difference between the two sets of coordinates the Clay Bank station moved 167 meters. I cannot account for this difference except to say the first set of reading was not a very accurate one. Those that moved the station say it was moved approximately 75 meters.
The Clay Bank profiles do not appear to show any difference between pre and post movement of the station due to the approximate 0.24m difference in depth. (A figure of 0.80 m was estimated at one point, but the 0.24 m difference is based on a measurement taken on station. Due to the placement of the sonde in the tube this results only in a change of approximately 0.09 meters. In the submission data for 2004 there is a note in the comments column telling the user that the station was moved so that information is available.
White House - White House was actually moved 0.5 meters from the original site that was damaged by ice after the first year. One can literally stand at the old site and touch the new one. Trimble coordinates are not yet available for this site.
Yorktown - The pre hurricane station and post hurricane station are at roughly the same depth - the station was re-established on the same depth contour it just shifted a bit laterally. Actual depth change of the water level of the datalogger was only 0.08 meters.
Walkerton – Walkerton was rebuilt due to damage from ice over the first winter. The “new” station was created in the foot print of the old station.
One issue with station IDs was discovered while going through this process. Originally the Taskinas Creek fixed station was going to be moved out into the York River. When station names were developed the same name was used for the Taskinas Creek fixed station as well as the dataflow verification station that was taken right outside the mouth of Taskinas Creek in which the fixed station is located. Since it was determined Taskinas Creek fixed station would stay it its original location, there now needs to be an ID for the fixed station. The current station YRK023.40 is where the verification station is located for Dataflow. A new station TSK000.23 was developed based on the following lat/lon (which came from the Trimble and is there for the most accurate possible) Lat: 37.41496902 and Lon: 76.714409 Data submission for 2004 will reflect this addition and 2003 data will be amended to reflect this change also.
Given the above information all station IDs with the exception of the Taskinas Creek fixed station will remain the same.
Process Description:
For Continuous Monitoring water quality parameters WTEMP, SPCOND, SALINITY, PH, DO_SAT, DO, TURB_NTU, FLUOR, TCHL, and DEPTH a YSI 6600 or YSI 6000 sonde unit was used. For LATITUDE and LONGITUDE, a Garmin GPSMAP 168 WAAS enabled GPS unit is used. The methods are found in the METHOD column, which corresponds to a method code. The data were uploaded to a PC from either YSI 6000 or 6600 dataloggers and reviewed using PC6000/6600 software from YSI. Graphs were produced and examined using the PC6000/6600 software then printed out and filed. Next, files were uploaded in comma-delimited format, which were opened in Excel 5.0 software and edited to remove extraneous information (headers, footers, spaces, and pre- and post-deployment data). Macros supplied by NERRS/CDMO and MD DNR were used to help with editing, formatting and identifying outliers in the database. Outliers were determined according to the instruments' manufacturers manual. Suspect data (as in data believed to result from a damaged or biofouled probe) were evaluated according to internal protocols and tagged accordingly in the PROBLEMS column associated with that parameter.
The methods used are as follows:
PARAMETER: CHLA and FLUOR
CBP METHOD: F01
EPA METHOD AND OTHER DESCRIPTION: In-situ measurement of in-vivo chlorophyll using a probe attached to a multi-parameter sonde. The instrument induces chlorophyll to fluorescence by shining a beam of light and then measuring the higher wavelength light which is emitted as a result of the fluorescence process. The output is processed via the sonde software providing readings in UG/L.
REFERENCE: YSI 6-Series Environmental Monitoring Systems Manual. Revision A. May 1999. YSI, Inc.; Yellow Spring: Oh: 264p.
PARAMETER NAME: SPCOND, conductivity, in-situ specific conductance at 25 C
CBP METHOD: F01