Acceptance and utilization of PIE-LTER data requires that:
· The Principal Investigator be sent a notice stating reasons for acquiring any data and a description of the publication intentions.
· 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.
· A copy of any resultant publications should be sent to:
(Principal Investigator)
Ecosystems Center;
Marine Biological Laboratory
Woods Hole, MA 02543
PLUM ISLAND ECOSYSTEM LTER DATABASE
DATA FILE: WAT-YSI_Urban_2003.txt
DOCUMENTATION FILE: WAT-YSI_Urban_2003.doc
YEAR: 2003
PI: Charles Vorosmarty
OTHERS: Wilfred Wollheim, Brian Pellerin
BRIEF DESCRIPTION OF DATA FILE: Continuous measurements, every 15 minutes, were made of stage, water temperature, conductivity, dissolved oxygen, and pH in a small headwater stream draining a highly suburban catchment (72% residential). Measurements are for the ice free season (March – December). Discharge is determined from stage using discharge vs stage regressions. Several day gaps occur periodically due to removal for recalibration.
KEYWORDS: suburban, discharge, water temperature, conductivity, pH, dissolved oxygen.
SITE TYPE: Watershed - Suburban
RESEARCH LOCATION: Locations are 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
EXPERIMENTAL DESIGN AND 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. After this
date, water depths are corrected to correspond with measurements prior to this
change. 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. See discussion
below for development of the discharge-stage relationship. Recalibration was performed roughly every
4-6 weeks. Instrument drift during
deployment periods was not significant.
NOTES AND COMMENTS:
Discharge measurements in Saw Mill are based on a power rating curve that contains measurements up to a depth of 0.6m. 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 5% of the readings in 2003 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.
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.
VARIABLE DESCRIPTION:
Date = date (yyyy-mm-dd)
Time = time (hh:mm:ss)
Temp = water temperature (oC)
SpCond = specific conductivity (mS/cm)
DO% = dissolved oxygen percent of saturation (%)
DOConc = dissolved oxygen concentration (mg/l)
Depth = stage height (m)
pH = log of the H+ ion concentration
Flow = discharge (l/s)
CALCULATIONS:
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
FOR MORE INFORMATION, CONTACT:
Wil Wollheim
OTHER DATA FILES TO REFERENCE:
All in the YSI series.
REFERENCE CITATIONS:
DATA AVAILABILITY STATUS:
Type 2
ARCHIVE INFORMATION:
Date of entry: Jan 21, 2004
Data entered by: W. Wollheim
Comments: