Year 2006, continuous measurements, every 10, 15 or 30 minutes, were made of stage, water temperature, conductivity in a small headwater stream, Bear Meadow Brook , Cedar Swamp, Reading MA, draining a mainly wetland catchment (49% wetland + 36% wetland). Discharge is determined from stage using discharge vs stage regressions.
YSI information is available from only a small portion of the year. This year, we shifted to using HOBO data loggers for our depth measurements. These can be deployed during the winter period. As a result, for most of the year, depth is based on measurements using a HOBO depth data logger. A borrowed HOBO was temporarily deployed between Jan and Mar 2006 in a temporary location. A new HOBO was permanently deployed in a stilling well in July 2006. Depth measurements by the HOBO deployed in the stilling well are considered reliable.
YSI: 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.
Recalibration of conducitivty and depth was performed roughly every 4-6 weeks. Instrument drift during deployment periods was not significant.
HOBO: 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. Between Jan and March 2006, a borrowed data logger was deployed attached to a cinder block placed on the stream bottom. A newly purchased HOBO data logger was deployed in a permanent stilling well in July 2006. The HOBO is deployed in a 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.
The hobo of Jan-Mar 2006 was standardized to the permanet HOBO using:
Jan-Mar 2006: YSI_Depth = TEMP_HOBO_DEPTH - 0.2696. HOBO_Depth = YSI_Depth + 0.205
NOTES AND COMMENTS:
Velocity measurements were made using a Marsh McBirney current meter. Discharge estimates in Cedar Swamp (Bear Br.) are based on a power rating curve that contains measurements up to a depth of 0.9 meters, as standardized to depth measured with the HOBO datalogger (Column = HOBO_Depth), which is above bankfull stage. Rating curve has been standardized to HOBO_Depth to allow application of a single rating curve across years. Rating curve has an R2 of 0.96 using 10 measurements between 2005 and 2007. All files in this series (2005-2006) are currently standardized to HOBO_depth.
The column Depth_Device is included when combining files from several years, over which several different devices were used to calculate depth. HOBO_Depth is the depth that is standardized across all measurement devices so that a single rating curve can be applied.
Discharge rating curve :
Discharge (l/s) = 1085.3 (depth) ^ 4.5944
where depth is HOBO_Depth
Periodic with improvement of rating curve, particularly as more high discharge events are incorporated.
This file was initially posted in September 2007.
Version 01, 30 Oct 2007 updated metadata to EML level 3+
Version 02, 21Jan2010 keyword update
Version 03: February 18, 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