Acceptance and utilization of LTER data requires that:
(1) The Principal Investigator be sent a notice stating reasons for acquiring any data and a description of the publication intentions.
(2) The Principal Investigator of the data set be sent a copy of the report or manuscript prior to submission and be adequately cited in any resultant publications.
(3) A copy of any resultant publications should be sent to:
Marine Biological Laboratory
7 MBL St.
Woods Hole, MA 02543
|Dataset URLs:||METADATA: HTML, Rich Text, XML(EML compliant) |
DATA: Comma Delimited, Excel file with Metadata and data
|Dataset Title:||Year 2002, 15 minute measurements of stage, water temperature, conductivity, dissolved oxygen, and pH in a small headwater stream draining a highly suburban catchment (72% residential), Saw Mill Brook, Burlington, MA.|
|Investigator 1:|| |
|Address line 1:||Morse Hall|
|Address line 2:||UNH|
|Address line 3:|
|Investigator 2:|| |
|Address line 1:||Morse Hall|
|Address line 2:||UNH|
|Associate Investigators:||Brian Pellerin|
|Keywords:||PIE LTER, disturbance, Saw Mill Brook, suburban, discharge, water temperature, water stage, conductivity, pH, dissolved oxygen.|
|Abstract:||Continuous measurements, every 15 minutes, were made of stage, water temperature, conductivity, and dissolved oxygen in a small headwater stream draining a highly suburban catchment (72% residential). Measurements are for part of the ice free season (June – December). Discharge is determined from stage using discharge vs stage regressions. Several day gaps occur periodically due to removal for recalibration.|
|Contact:||Plum Island Ecosystems LTER Information Manager
The Ecosystems Center
Marine Biological Lab
7 MBL St
Woods Hole, MA 02543
Phone (508) 289 7485
Online URL: http://ecosystems.mbl.edu/PIE/
|DATA FILE INFORMATION:|
|Data File URL||http://ecosystems.mbl.edu/PIE/data/WAT/data/WAT-YSI-Urban-2002.dat|
|Data File Name||WAT-YSI-Urban-2002|
|Number of Data Records||22491|
|Other Files to Reference||All in the YSI series.|
|Availability Status||Type 1|
|Quality Control Information|
|Maintenance Description||Periodic with improvement of rating curve, particularly as more high discharge events are incorporated.|
|Log of Changes:||This file was updated in September 2007 to incorporate an improved rating curve that includes higher discharge events. Flow data from previous version is maintained for comparison.|
|Version 01, 30 Oct 2007 updated metadata to EML level 3+|
|Version 02, 21Jan2010 keyword update|
|Version 03, 25May2010, date and rating curve data update, revised in 2009 to standardize YSI depths to HOBO datalogger depths used in later years - uses revised rating curve that includes all measurements between 2001 and 2009|
|RESEARCH LOCATION:||Site 1||Site 2|
|Location Bounding Box|
|West Bounding Coordinate|
|East Bounding Coordinate|
|North Bounding Coordinate|
|South Bounding Coordinate|
|OR if single point location|
|Methods:||YSI 6200 data sondes were deployed vertically in a pool deep enough to contain water during dry conditions. The sonde was deployed in a PVC tube, which was attached to ree-bar driven into the stream bed. The PVC tube had holes drilled to allow adequate water circulation. Dissolved oxygen measurements are of poor quality because the the bottom of the pool was often filled in with detritus following intermediate sized storms, leading to anoxic conditions. To alleviate this problem, the PVC tube was raised 10.1 cm on 7/16/03. The file for 2001 includes the raw depth measurement (RAWYSI_Depth), as well as the depth measurement corrected to the YSI depth after the change in tube height (YSI_Depth_STD) and for which the rating curve has been standardized.|
The PVC tube was surveyed upon original deployment in 2001 and resurveyed in 2002 to ensure that elevation did not change during winter ice period. No change was detected. No evidence of change has been noted through 2006 based on discharge measurements. See discussion below for development of the discharge-stage relationship.
Recalibration of oxygen, conducitivty and depth was performed roughly every 4-6 weeks. Instrument drift during deployment periods was not significant.
ADDITIONAL RESEARCH LOCATION COORDINATES: In addition to the decimal degree coordinates given above, locations are also given here in Massachusetts State Plane coordinates. The stream is called SawMill Br. and is located in Burlington MA. Small amounts of forest remain (~14% in 1999), much of which is along the stream channel near the gaging site.
STATION STATE X STATE Y
YSI-SB 225840 919310
NOTES AND COMMENTS:
Dissolved oxygen concentrations generally reflect water column levels. However, due to the position of the sonde, detritus periodically covered the bottom of the sondes where the D.O. probe is located, leading to anoxic conditions. It is likely that low D.O. levels reflect benthic conditions.
Velocity measurements were made using a Marsh McBirney current meter and starting in 2009 with a Sontek Flowtracker. Discharge estimates in Saw Mill are based on a power rating curve that contains measurements up to a stage depth of 1.2 meters, which is above bankfull stage. Rating curve has an R2 of 0.89 using 40 measurements between 2001 and 2009. The rating curve has not noticeably changed over the period. Prior to 2007, stage was measured with various other instruments (YSI, Sigma depth sonde, HOBO). All files in this series (2001-2009) are now standardized to HOBO depth. The rating curve is based on the standardized HOBO depth's (and actual HOBO depths since 2007).
Discharge rating curve :
Discharge (l/s) = 889.65*depth^5.8788
where depth is Adj_HOBO_Depth
Several depth are included in this file to allow comparison with earlier file version. RAWYSI_Depth is the depth measured by the YSI and is used by an initial, preliminary rating curve. YSI_Depth_STD is depth adjusted to standardize for the change in stilling well depth in July 2003. The column Depth_Device is included when combining files from several years, over which several different devices were used to calculate depth. Depth_STD is the depth that is standardized across all measurement devices so that a single rating curve can be applied. The rating curve is standardized to the Hobo depth measurements, which were started in 2006. The difference between Hobo data logger depth measurements and YSI data logger depth measurements (YSI_DEPTH_STD) is 0.211m
(StandardizedHoboDepths = YSI_Depth_STD + 0.21)
Also, at times depth and discharge may be periodically erroneous due to leaf pack accumulation at a riffle downstream causing backup. We remove this whenever we visit the site. Generally we believe the depth error is on the order of 2-4 centemeters. The depth data have not been corrected for errors associated with temporary debris dams.
OLD RATING CURVE ( prior to Sept 2009 revision):
Discharge measurements in Saw Mill are based on a power rating curve that contains measurements up to a depth of 0.6m (using the column RAWYSI_Depth). Flows above this amount are estimated using a linear extrapolation using the six measurements with the highest flow. Thus flows determined from levels greater than 0.6m are approximate (roughly 1% of the readings in 2001 deployment period). Rating curve below 0.6m is based on a power relationship with an R2 = 0.98. Measurements are based on 12 measurements taken between 2001 and 2003.
When stage in SawMill Br. is less than 0.6m :
Discharge (l/s) = 1245.2 (depth) 4.782
When stage in SawMill Br. is greater than 0.6m :
Discharge (l/s) = 560.7 (depth) – 229.8
|Variable Name||Variable Description||Units||Measurement Scale||Code Information||Number Type||DateTime Format||Missing Value Code||Missing Value Code Explanation|
|Date||date (yyyy-mm-dd)||datetime||yyyy-mm-dd||blank cell|
|Time||time (hh:mm:ss) 24 hour||datetime||hh:mm:ss||blank cell|
|Temp||water temperature (oC)||celsius||interval||real||blank cell|
|SpCond||specific conductivity (mS/cm)||millisiemensPerCentimeter||ratio||real||blank cell|
|DO%||dissolved oxygen percent of saturation (%)||percent||ratio||real||blank cell|
|DOConc||dissolved oxygen concentration (mg/l)||milligramsPerLiter||ratio||real||blank cell|
|pH||log of the H+ ion concentration||dimensionless||ratio||real||blank cell|
|RAWYSI_Depth||stage height measured by YSI (m)||meter||ratio||real||blank cell|
|YSI_Depth_STD||stage height measured by YSI (m) (standardized)||meter||ratio||real||blank cell|
|OLD-Discharge||discharge using OLDYSI_Depth and earlier rating curve (l/s)||litersPerSecond||ratio||real||blank cell|
|Depth_Device||depth measurement device used to determine discharge||nominal||YSI = YSI depth sonde | SIGMA = Sigma autosampler depth sonde | TEMP_HOBO = HOBO depth sonde deployed in temporary stilling well | HOBO = HOBO depth sonde deployed in permanent stilling well||blank cell|
|StandardizedHoboDepths||depth standardized to rating curve using HOBO depths||meter||ratio||real||blank cell|