Plum Island Ecosystems LTER Database

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:

Principal Investigator
Ecosystems Center
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 ID:WAT-YSI-Urban-2010.02
Dataset Title:Year 2010, 15 minute measurements of stage in a small headwater stream draining a highly suburban catchment (72% residential), Saw Mill Brook, Burlington, MA.
Investigator 1: 
First Name:Wilfred
Last Name:Wollheim
Address line 1:Morse Hall
Address line 2:UNH
Address line 3:
Zip Code:03824
Associate Investigators:Nat Morse, Amanda Hope
Keywords:PIE LTER, disturbance, Saw Mill Brook, suburban, discharge, water temperature, water stage.
Abstract:Year 2010, continuous measurements, every 15 minutes, were made of depth and stream temperature in a small headwater stream, Saw Mill Brook, Burlington, MA, draining a highly suburban catchment (72% residential). Discharge is determined from stage using discharge vs stage regressions.
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:
Data File URL
Data File Name WAT-YSI-Urban-2010
Beginning Date 1/1/2010
End Date 12/31/2010
Number of Data Records 30702
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: Version 01, 27Jun2012, data and metadata updated. Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 3/23/2012 12:08 PM for QA/QC to EML 2.1.0.
Version 02: February 11, 2014, data and metadata updated to comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007_Sep2013.xlsm 9/30/13 02:57 PM for QA/QC to EML 2.1.0
Geographic Description Watershed water collection and stream characterization site for Saw Mill Brook (urban landuse), Burlington, MA  
Location Bounding Box    
West Bounding Coordinate    
East Bounding Coordinate    
North Bounding Coordinate    
South Bounding Coordinate    
OR if single point location    
Latitude 42.5236  
Longitude -71.185  
Taxonomic Protocols
Organisms studied
Methods:This file consists of depth data collected using a HOBO datalogger deployed in a stilling well in the stream channel.

HOBO Datalogger: Depth and water temperature are recorded by the HOBO data logger. Depths are corrected for barometric pressure changes using readings in an additional HOBO datalogger deployed at Marshview Farm. The HOBO is deployed in a PVC tube, which was attached to ree-bar driven into the stream bed. The PVC tube has holes drilled to allow adequate water circulation.

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.

YSI-SB 225840 919310

There appears to have been a major shift in the rating curve in early 2010. Discharge estimated in January 2010 is calculated using the old rating curve. For the old rating curve, velocity measurements were made using a Marsh McBirney current meter and contains measurements up to a stage depth of 1.2 meters, which is above bankfull stage. Rating curve has an R2 of 0.88 using 40 measurements between 2001 and 2009. 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) = 896.47*depth^5.7352
where depth is Adj_HOBO_Depth

For all discharge estimates after March 2010, a new rating curve was used. Starting in 2010, discharge measurements are being made with a Sontek FlowTracker. The new rating curve has an R2 of 0.96 and includes 13 discharge measurements at flows below bankful taken after March 2010 and 2 measurements that were taken at flows above bankful in 2006.

Discharge rating curve :
Discharge (l/s) = 1380.4*depth^4.4564
where depth is Adj_HOBO_Depth


Data is missing between 2010-1-30 and 2010-3-9 and between 2010-8-26 and 2010-9-1.


Since our Hobo dataloggers are placed in stream reaches with minimal artificial engineering (i.e. v-notch weirs, etc.), there are occasional environmental factors than influence the Hobo depth readings that must be corrected to accurately reflect the true conditions of the stream reach. These include silt/sand build-up in and around the stilling well or downstream debris dams that artificially elevate the water level of the pool where the hobo is located. We attempt to correct these changes to provide best estimates of stream depth and corresponding discharge. Especially with debris dams, we assume a slow build-up of debris and apply an accumulating off-set based on the amount of time betwen site visits. We note the reasons for all corrections using the "Flag" column in the spreadsheet and the explanations are below.

1 -- Discharge estimated using old rating curve
2 -- Accumulating offset to adjust for change to hobo stilling well (0.116 m) that occurred on June 18
3 -- Accumulating offset to adjust for slow build-up of debris dam (0.02 m) in riffle downstream that elevated pool height

Data Table

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 NA NA = not available
Time time (hh:mm))   datetime     hh:mm NA NA = not available
Temp water temperature (oC) celsius interval   real   NA NA = not available
HOBO_Depth stage height measured by HOBO (m) meter ratio   real   NA NA = not available
Correction_Factor Necessary adjustment for HOBO meter ratio   real   NA NA = not available
Adj_HOBO_Depth HOBO depth + CorrectionFactor (see methods) meter ratio   real   NA NA = not available
Depth_Device depth measurement device used to determine discharge   nominal HOBO = HOBO depth sonde deployed in permanent stilling well     NA NA = not available
Discharge discharge literPerSecond ratio   real   NA NA = not available
Flag Code referring to comment about the data (explanation in methods)   nominal 1 = Discharge using old rating curve | 2 = Accumulating offset to adjust for change to hobo stilling well (0.116 m) that occurred on June 18 | 3 = Accumulating offset to adjust for slow build-up of debris dam (0.02 m) in riffle downstream that elevated pool height