Santee Experimental Forest, Watershed 77: streamflow, water chemistry, water table, and weather data

Metadata:

Identification_Information
Data_Quality_Information
Entity_and_Attribute_Information
Distribution_Information
Metadata_Reference_Information

Identification_Information:

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:: STREAMFLOW:

Stage was measured to the nearest 0.01 foot. See the process steps for details on calculating specific values.

WATER QUALITY:

The accuracy and resolution of the parameters measured by the Manta are listed below:
pH: accuracy = +/- 0.2 units; resolution = 0.01 units;
temperature: accuracy (over the range of -5 to 50 degrees Celsius (°C)) = +/- 0.08°C; resolution = 0.01°C;
specific conductance: accuracy (over the ranges of 0 - 5, 5 - 25 and 25 - 112 microS per centimeter) = +/- 1% reading +/- 0.001, +/- 1% reading, and +/- 1% reading, respectively; resolution = to 4 digits;
salinity: accuracy (over the range 0 - 70 PSS) = +/- 1% reading +/- 1 count; resolution = 0.01 PSS; and
dissolved oxygen: accuracy (over the range 0 - 50 milligrams per liter (mg/L)) = +/- 0.2 mg/L (for less than or equal to 20 mg/L) and +/- 0.6 mg/L (for greater than 20 mg/L).

The accuracy and resolution of pH measurements made using the PC 300 Meter are listed below:
pH: accuracy = +/- 0.01 units; resolution = 0.01 units.

The accuracy and resolution of the parameters measured by the Hanna are listed below:
pH: accuracy = +/- 0.02 units; resolution = 0.01 units;
temperature: accuracy = +/- 0.15°C; resolution = 0.01°C;
specific conductance: accuracy = +/- 1% of reading; resolution = 0.001 milliSiemens/centimeter (mS/cm) from 0.000 to 9.999 mS/cm;
salinity: accuracy = +/- 2% of reading; resolution = 0.01 PSU; and
dissolved oxygen: accuracy (over the range 0.00 to 30.00 mg/L) = +/- 1.5% of the reading or +/- 0.10 mg/L, whichever is greater; resolution = 0.01 mg/L.

WATER TABLE:

Original water level measurements were recorded in feet (ft) above the pressure transducer (with a precision of 0.01 ft). These measurements were later converted to centimeters (cm) below ground surface and elevation (m) relative to mean sea level.

WEATHER:

The accuracy and resolution of the TMCx-HD air/soil temperature probes:
accuracy is +/- 0.25°C from 0-50°C when used with a U12-type data logger; resolution is 0.03°C at 20°C.

The accuracy and resolution of the RG2M tipping bucket gauge:
calibration accuracy is +/- 1% (up to 20 millimeters [mm] per hour); resolution is 0.2 mm.

Manual rainfall measurements were made using a 0.20 m (8-inch) diameter National Weather Service (NWS) Standard Rain Gauge.

On 7/29/2009, the existing H08-02 temperature data logger was replaced by a new unit, the HOBO U12 4-External Channel Outdoor/Industrial data logger (using channels 3 and 4 for air and soil temperature, respectively).

The Hobo rainfall event logger was replaced by a Pendant logger on 12/11/2014.

The TMC1-HD air temperature sensor was replaced on 06/24/2015.

The aging wooden temperature sensor enclosure was replaced on 04/21/2016. On 04/27/2016, a new TMC6-HD soil temperature sensor was installed.

On 01/03/2018 there was freezing rain and snowfall, and after that time snow froze and thawed slowly over several days. No accurate event data were recorded during or immediately after this freezing rain and snow event, so we used Pluvio weighing bucket percentages and the post-event Met 5 meltwater total to estimate hourly precipitation.

The TMC1-HD air temperature sensor was replaced on 05/02/2018.

We replaced the malfunctioning Pendant logger with another Hobo rainfall event logger on 09/11/2018 in advance of Hurricane Florence.

Logical_Consistency_Report:

STREAMFLOW:

Visual inspection and comparison with flow data from other SEF flow gauging stations (as well as daily rainfall data) were used to expose anomalous data.

The measurement interval changed from 10 minutes to 15 minutes (and then back again) between 02/20/2004 0:00 and 06/14/2004 14:00.

The ISCO 4210 flow meter was replaced by a new ISCO Signature flow meter and ultrasonic sensor on 08/23/2018, and the recording interval was changed to 15 minutes.

WATER QUALITY:

Laboratory analyses during the 1976-1982 period followed the protocols effective at the Forest Soils Laboratory at Duke University.

During the 1989-1994 period, laboratory analyses were performed in the USDA Forest Service analytical laboratory at its facility in Charleston, SC. These analyses were carried out according to protocols specified in the following volume:

Standard Methods for the Examination of Water and Wastewater. Clesceri, L.S. (ed.); Greenberg, A.E. (ed.); Eaton, A.D. 1989. American Public Health Association. Washington, DC.

Laboratory analyses from March 2003 through February 2007 followed standards described in "SEF_Laboratory_Manual_01-09-14" (included in the data publication download), a summary of sample collection, handling, transporting, processing, preservation and instrumental analysis protocols compiled by Ms Lara Matthews, Laboratory Manager at the Center for Forested Wetlands Research in October 2006. Analytical instruments were calibrated with known standards before every sample run, and laboratory analyses of sample sets always included at least 10% duplicate, blank and spiked samples for quality assurance.

Starting in March 2007 the initial sample processing continued as above, but instrumental analyses followed standards described in "Procedures for Chemical Analysis" (wetlab-cookbook_revised-2017-08-08.pdf, included in data publication download), a laboratory manual compiled by Mr. James M. Deal and revised by Ms. Cindi Brown and others that summarizes protocols employed at the Coweeta Hydrologic Laboratory, 3160 Coweeta Lab Road, Otto NC 28763.

Calibration and field use of the Manta multiprobe were performed as recommended in the "Manta Water Quality Multiprobe Startup Guide," version dated June 4, 2004 (Eureka Environmental Engineering, 2113 Wells Branch Parkway Suite 4400, Austin TX 78728).

Problems with the pH sensor in the Manta multiprobe started to develop in March 2016, and we switched to measuring pH in the field with the Oakton PC 300 Waterproof Hand-held pH/Conductivity/TDS/Temperature Meter on October 28, 2016. Calibration and field use of the PC 300 Meter were performed as recommended in the Instruction Manual for the PC 300, rev. March 5, 2008 (Oakton Instruments, P.O. Box 5136, Vernon Hills IL 60061).

In September 2017 we started using the Hanna HI98194 multiprobe for measurement of pH, temperature, specific conductance, salinity and dissolved oxygen. Calibration and field use of the HI98194 multiprobe were performed as recommended in the Instruction Manual for the HI98194, HI98195 and HI98196 Multiparameter Meters (Hanna Instruments Inc., Highland Industrial Park, 584 Park East Drive, Woonsocket RI 02895).

The Hanna multiprobe broke during early December 2018, and no new data has been collected since then.

WATER TABLE:

Visual inspection of electronically plotted water table data and comparison with precipitation data from other SEF stations was employed to expose anomalous values for the expected water table response to rainfall.

WEATHER:

Visual inspection of electronically plotted temperature and precipitation data and comparison with data from other nearby SEF stations were employed to expose anomalous values.

Completeness_Report:

Blank cells indicate data are missing. For data such as rainfall, a 0 indicates there was zero rainfall.

STREAMFLOW:

Flow monitoring was discontinued starting 11/01/1981 but was resumed on 11/14/1989 following the devastation caused by Hurricane Hugo on 09/21/1989. Since then there have been a number of brief periods with missing data, largely the result of equipment failures or personnel vacancies.

No reliable flow data are available for WS77 from 12/18/2000 through 02/20/2003. However, South Carolina was experiencing a severe drought during much of this period (South Carolina Department of Natural Resources declared that the drought had ended in Berkeley County in November 2002) and there was little or no flow at the gauging station during the drought. Since then there have been brief periods of missing data, largely as a result of equipment failures.

WATER QUALITY:

Stream water samples were collected by the automated sampler at the gauging station during periods of active flow on a flow-proportional basis; during periods without flow no samples were collected. Infrequent equipment malfunctions also occasionally resulted in samples being missed. While the Center for Forested Wetlands Research was in the process of relocating its offices and labs from Charleston to the Santee Experimental Forest in Cordesville, collection of water quality samples at the WS77 gauging station was discontinued temporarily between March and December 2007.

Missing Data (2003 - 2007) -

The following outliers have been removed:
11/25/2006 11:15 (TDP value)
03/08/2003 08:48 (Cl value)
03/08/2003 10:02 (Cl value)

None of the potential reasons for other possible outliers can be confirmed, and so these values have been retained in the data set and it is at the discretion of the user to exclude them.

Manta data missing for following periods:
06/01/2007 (dissolved oxygen [DO] values removed; at or above 100%)
06/15/2007 (DO values removed; at or above 100%)
06/29/2007 (DO values removed; at or above 100%)
08/03/2007 (DO values removed; at or above 100%)
08/10/2007 (too little water behind weir to sample)
08/23/2007 (too little water behind weir to sample)

All pH, conductivity and salinity data for 2006 and 2007 were removed because of questions about instrument calibration during the period.

Outliers, negative values and missing data (2008 - 2019) -

The following outliers have been removed:
07/21/2018 04:06 TDN, TDP, NH4, PO4
06/10/2019 9:05 TDN, TDP, NH4, PO4

There are a number of possible outliers, including the following dates and analytes:
12/03/2008 14:34 K
01/06/2009 10:34 Mg
01/27/2009 02:19 Cl
04/02/2009 15:52 NO3/NO2
05/26/2009 08:38 Ca (somewhat elevated concentrations observed in blank)
11/13/2009 09:32 Br
07/17/2010 06:25 TDN, TDP, NH4, K, Na, PO4
06/08/2016 08:27 TDP, PO4
12/06/2016 22:04 Br
10/09/2017 23:40 PO4
12/15/2017 11:07 Cl
06/10/2019 09:05 K
06/11/2019 12:56 SO4
07/07/2019 19:09 NO3
08/25/2019 07:03 DOC

Because none of the potential reasons for the extreme values can be confirmed, these and other possible outliers have been retained in the data set and it is at the discretion of the user to exclude them.

TDN and DOC values from 03/24/2015 9:09 and 11/09/2015 22:30 represented probable blanks and thus were removed as outliers.

DOC data from samples collected during the June 11, 2012 to April 22, 2013 period have been removed as suspect because of concerns raised at the Coweeta Hydrologic Laboratory (their instrument may have been measuring Total Carbon instead of Dissolved Organic Carbon during this period).

A small number of negative values were recorded for certain analytes (e.g., TDP and Mg). Following the policy of the Coweeta Hydrologic Laboratory, these values have been replaced with "0.001"

Manta data missing for following periods:

All pH, conductivity and salinity data for 2008 were removed because of questions about instrument calibration during the period.

08/16/2013 (specific conductivity and salinity values removed as outliers)
08/08/2014 09:09 (all data)
09/11/2014 12:39 (all data)
03/04/2016 (suspect pH data removed)
10/28/2016 (only pH data available)

Manta data not available from November 2015 through early February 2016 because of problem with cable, and also not available from early March 2016 through early June 2016 because of sensor problems.

The Hanna multiprobe broke during early December 2018, and no new data has been collected since then.

WATER TABLE:

Water table levels in the first well network were manually monitored approximately every two weeks between 1964 and 1971. Another network of wells was established in 1992, and it was monitored in a similar manner until 1995.

Since 2005, hourly measurements were recorded by the data loggers, except during the occasional battery failure or equipment malfunction.

WEATHER:

During the early years (prior to 1996) the manual rain gauges were usually read only after rain had fallen. However, if rain fell on a weekend or on a holiday, the rain gauge was not read until the next work week. Therefore, even though the plan was to collect daily total rainfall, the time interval was not always one day and more than one precipitation event may have occurred between readings.

There is a large gap in the Met 5 precipitation data from October 1966 to November 1989, when rainfall measurements were resumed at this station following the devastation caused by Hurricane Hugo. There were brief periods of missing data until August 1997, when another long data gap began (lasting until November 2001).

Between February 1996 and January 2001 there were occasional gaps in the data (some lasting a few months) resulting from equipment failures.

No manual rain gauge data were available until the period starting 11/16/2001, so tipping bucket gauge data recorded prior to that date could not be used. Since then there have been brief periods of missing rainfall and/or air and soil temperature data, usually as the result of equipment malfunction.

Because of a problem with the TMC1-HD air temperature sensor that developed on 06/14/2015, some data between that date and 06/24/2015 (when the sensor was replaced by another TMC1-HD unit) have been removed.

Because the manual rain gauge overflowed, data for massive rain event that occurred during the 10/02/2015 to 10/08/2015 period was extrapolated using the rainfall ratio (manual total/tipping bucket total) from 09/29/2015 to 10/02/2015.

There are brief periods of missing air temperature data from 10/20/2015 through 04/21/2016 because of spiky values that resulted from missing slats on the wooden enclosure. Soil temperature data are missing between 04/21/2016 and 04/27/2016 because of the transition to the new wooden temperature sensor enclosure.

Lineage:

Methodology:

Methodology_Type: Field
Methodology_Description:: STREAMFLOW:

In 1963 the Forest Service constructed a compound metallic and concrete v-notch weir in a concrete wall, and an associated blockhouse (to house monitoring instruments), at the WS77 outlet on Highway 41. Stage data were recorded on tapes at 15-minute intervals by analog-to-digital water level recording (ADR) equipment.

In September 1995 the ADR equipment was replaced by a Teledyne-ISCO 3210 flowmeter. 15-minute stage data were downloaded directly to a computer in the field using Flowlink 3 software.

A Teledyne-ISCO 4210 flowmeter with an ultrasonic sensor was installed on 08/05/2002 (replacing a 3210 unit), but it was only programmed to record calculated flow rates (not stage) on a 10-minute interval. This programming was corrected on 02/20/2003 so that the 4210 recorded 10-minute stage levels. The 10-minute stage data were downloaded directly to a computer in the field using Flowlink 4 software. The calibration of the ultrasonic sensor was checked regularly against the level of water above or below the v-notch in the weir. If the readings differed by 0.01 foot or more, the 4210 was recalibrated.

Robert Johnson Masonry repaired a gap in the downstream north side weir wall on 04/19/2017.

Trainum Brothers Co. installed a new wooden platform and safety railing at the site on 06/13/2017.

The ISCO 4210 flow meter was replaced by a new ISCO Signature flow meter and ultrasonic sensor on 08/23/2018, and the recording interval was changed to 15 minutes.

Methodology:

Methodology_Type: Field
Methodology_Description:: WATER QUALITY:

Approximately weekly water samples were collected upstream of the WS77 weir between 11/04/1976 and 10/27/1982, and then again between 10/13/1989 and 12/29/1994.

During the 1989-1994 period, weekly water samples were collected upstream of the WS77 weir in clean plastic bottles and returned to the laboratory on ice. At the time of sample collection, stream pH was measured using a hand-held Oakton meter and probe.

Starting in March 2003, during periods of active stream flow a Teledyne-ISCO 4210 flow logger/ultrasonic sensor, calibrated to the level of water above or below the v-notch in the WS77 weir, signaled a Teledyne ISCO 3700 automated sampler to take a 200-milliliter (ml) water sample after a known amount of water had passed over the weir (730.5 cubic meters; amount based on the median volume of historic flow events). Such samples were collected using 3/8 inch vinyl suction tubing attached to the sampler and extending to the center of the stream, where the intake strainer was installed about 1 foot (ft) below the bottom of the v-notch in the weir. Samples were composited (4 samples per 1000 ml bottle), and approximately once a week filled bottles were removed from the autosampler and replaced with clean, acid-washed bottles. The sample bottles were taken to the laboratory in coolers and either filtered immediately (through 0.45 micron, 47 millimeter (mm) WCN type filters) or frozen until filtration could begin. Starting in December 2007 the bottles were no longer frozen but were kept at 4 degrees Celsius (°C) and filtered as soon as possible. (These data are referenced as sample_type = "Auto" in the data)

Beginning in July 2006, the Manta multiprobe (linked to the Amphibian data logger) was taken to the WS77 gauging station about once a week and used to measure pH, temperature, specific conductance, salinity and dissolved oxygen in the pool behind the weir plate (if enough water was present to submerge the probe) at the gauging station. In 2009 the Manta measurement interval became approximately bi-weekly.

Manta measurements were discontinued from November 2015 through early February 2016 because of problems with the cable, and then again from early March 2016 through early June 2016 because of sensor problems.

Beginning on October 28, 2016 measurements of pH were performed in the field using an Oakton PC 300 Waterproof Hand-held pH/Conductivity/TDS/Temperature Meter.

In September 2017 we started using the Hanna HI98194 multiprobe for measurement of pH, temperature, specific conductance, salinity and dissolved oxygen.

The Hanna multiprobe broke during early December 2018, and no new data has been collected since then.

We replaced the hard shell bottles in the Teledyne ISCO 3700 automated water quality sampler with Teledyne ISCO ProPak frames and EPA-approved LDPE plastic inserts on 8/30/2017.

Methodology:

Methodology_Type: Lab
Methodology_Description:: WATER QUALITY:

During the 1976-1982 period water samples were analyzed for pH (using a glass electrode) and bicarbonate (by acid titration to pH 4.5) within hours of collection. Samples were then preserved using phenol mercuric acetate (PMA) and frozen until shipment to the Forest Soils Laboratory at Duke University for further analysis (Richter 1980, Gilliam 1983).

Methods used for nutrient analysis of water samples at the Forest Soils Laboratory were the following:

Organic N: Kjeldahl digestion followed by dichloroisocyanurate colorimetry
NH4-N: Dichloroisocyanurate colorimetry
NO3-N: Azo dye colorimetry
SO4-S: Methylthymol blue colorimetry
Cl: Ferric thiocyanate colorimetry
PO4-P: Molybdenum blue colorimetry
Ca, Mg, K, and Na: Atomic absorption spectrophotometry

During the 1989-1994 period, samples were brought to the Charleston laboratory and refrigerated until processing could begin. The samples were filtered (details of filtration procedure are not known at this time) and then subjected to analysis according to standard protocols (Clesceri et al. 1989).

Most analyses (NO3/NO2-N, NH4-N, PO4-P, Cl, SO4, SiO3, TKN and TDN) were performed using the Technicon TRAACS-800 system. Cation analyses (K, Na, Ca, and Mg) were performed using a Perkin-Elmer Model 3100 Atomic Absorption Spectrometer.

Finally, HCO3 was measured by the titration method using an automatic titrimeter.

Laboratory methods from March 2003 to February 2007 were as described in "SEF_Laboratory_Manual_01-09-14" (included in the data publication download), a summary of sample collection, handling, transporting, processing, preservation and laboratory analysis protocols compiled by Ms. Lara Matthews, Laboratory Manager at the Center for Forested Wetlands Research in October 2006.

Briefly, the laboratory protocols involved the following:

After filtration through 0.45 micron, 47 mm WCN type filters, each sample was aliquoted to three labeled 125 milliliter (ml) HDPE sample bottles and one labelled 40 ml amber VOA vial for preservation and subsequent analyses. 140 microliters of a concentrated acid was added to each of three aliquots: H2SO4 in the 125 ml bottle for NH4, NO3/NO2, total dissolved N and total dissolved P analyses; HNO3 in the 125 ml bottle for cation analyses; and H3PO4 in the 40 ml vial for DOC analysis. The remaining 125 ml bottle (for Cl analysis) received no preservative. All sample aliquots were refrigerated until analyses could be performed.

The analyses, instruments used and method detection limits (mdl) during this period were the following:

TDN: performed using QuikChem© Method 10-107-04-3, In-Line Digestion followed by FIA on a LachatQuickChem FIA+ Autoanalyzer; mdl = 0.5 mg per L before March 2004, 0.3 mg per L (March 2004 to July 2005), and 0.1 mg per L after July 2005;

TDP: performed using QuikChem© Method 10-115-01-3, FIA Colorimetry (In-Line Persulfate Digestion Method) on a LachatQuickChem FIA+ Autoanalyzer; mdl = 0.1 mg per L before July 2005 and 0.01 mg per L after July 2005;

NO3/NO2-N: performed using QuikChem© Method 10-107-04-1, Flow Injection Analysis (FIA) on a LachatQuickChem FIA+ Autoanalyzer; mdl = 0.2 mg per L before July 2005 and 0.02 mg per L after July 2005;

NH4-N: performed using QuikChem© Method 10-107-06-1, FIA Colorimetry on a LachatQuickChem FIA+ Autoanalyzer; mdl = 0.1 mg per L before July 2005 and 0.02 mg per L after July 2005;

Cl: performed using QuikChem® Method 10-117-07-1-C, FIA Colorimetry on a LachatQuickChem FIA+ Autoanalyzer; mdl = 0.1 mg per L;
Ca, K, Mg, Na, P: performed using a Jobin Yvon Ultima II Inductively Coupled Plasma Spectrometer; mdl = 0.05 mg/L; and

DOC: performed using a Tekmar Phoenix 8000 Total Organic Carbon Analyzer; mdl = 0.1 mg per L.

Starting in March 2007 instrumental methods were as described in "Procedures for Chemical Analysis" (wetlab-cookbook_revised-2017-08-08.pdf, included in data publication download) a laboratory manual compiled by Mr. James M. Deal and revised by Ms. Cindi Brown and others that summarizes protocols employed at the Coweeta Hydrologic Laboratory, 3160 Coweeta Lab Road, Otto NC 28763.

As mentioned in the section on field methodology, starting in December 2007 samples collected in the field were no longer frozen before processing but instead were refrigerated and filtered (using 0.45 micron, 47 mm WCN type filters) as soon as possible. The filtrate was aliquoted to two labeled plastic 50-ml tubes (one each for cation and anion analyses) and two labeled, combusted (4 hours at 500°C) glass 40-ml vials (for DOC analysis). Filtered samples in plastic vials were frozen and those in glass vials refrigerated prior to overnight shipment to the Coweeta Hydrologic Laboratory for analysis.

Starting in February 2009, the above filtrate was aliquoted to three labeled plastic 50-ml tubes and all were frozen prior to shipping to the Coweeta Hydrologic Laboratory.

In June 2016 a new processing method for DOC samples and blanks was adopted: beginning on 06/20/2016, sample tubes designated for DOC analysis were pre-rinsed in 10% HCL followed by a triple-rinse in DI water.

Samples collected on 10/03/2016, as well as frozen filtered samples collected and processed on or after 09/16/2016, were exposed to room temperature sometime after 10/05/2016 due to power outage resulting from Hurricane Matthew. These samples were moved to an outbuilding on 10/11/2016 to keep cool until 10/12/2016 13:30, after power had been restored.

Samples collected on 10/11/2016 were stored in an outbuilding to keep cool until 10/12/2016 13:30, after power had been restored.

Because of problems with the ultrapure water system, filters used to process samples collected on or after 12/19/2016 were pre-soaked in DI, not ultrapure, water prior to use.

The analyses, instruments used and average method detection limits (mdl) during the March 2007 through 2019 period were the following:

TDN: determined by luminescence using a Shimadzu DOC-VCPH TN analyzer until November 2016, and then by luminescence using a Shimadzu DOC-VCPH TNM-1 analyzer starting in November 2016; average mdl = 0.015 mg per L (range = 0.006-0.038 mg per L) through November 2016; average mdl = 0.014 mg per L for December 2016; and average mdl = 0.008 mg per L for 2017 through 2019 (range = 0.007-0.011 mg per L).

TDP: performed using persulfate in line UV digestion on a LachatQuickChem FIA+ Autoanalyzer until April 2011, when the Lachat results became unreliable, and then determined by optical emission using a Jobin Yvon Ultima II Inductively Coupled Plasma Spectrometer (first acidifying the sample with 0.3% HNO3) through November 2012, and by optical emission using a Thermo Fisher iCAP 6300 starting in December 2012; average mdl = 0.003 mg per L (range = 0.001-0.005 mg per L) through April 2011, average mdl = 0.024 mg per L for the remainder of 2011 through 2012 (range = 0.002-0.046 mg per L), and average mdl = 0.003 mg per L from 2013 to 2019 (range = 0.001-0.008 mg per L);

NO3/NO2-N: determined by Micro-membrane Suppressed Ion Chromatography, using an AS 18 column, on a Dionex Ion Chromatograph ICS2500; average mdl = 0.002 mg per L (range = 0.0002-0.006 mg per L);

NH4-N: performed using the automated Phenate method on an Astoria 2 Autoanalyzer through November 2015, and usiing the automated Phenate method on a new Astoria 2 Autoanalyzer from December 2015 through 2018; average mdl = 0.004 mg per L (range = 0.001-0.009 mg per L) through November 2015, and average mdl = 0.001 mg per L from December 2015 through 2019 (range = 0.001 to 0.002 mg per L);

Cl: determined by Micro-membrane Suppressed Ion Chromatography, using an AS 18 column, on a Dionex Ion Chromatograph ICS2500; average mdl = 0.014 mg per L (range = 0.001-0.065 mg per L);

Ca: determined by optical emission using a Jobin Yvon Ultima II Inductively Coupled Plasma Spectrometer through November 2012, and by optical emission using a Thermo Fisher iCAP 6300 starting in December 2012; average mdl = 0.043 mg per L (range = 0.017-0.095 mg per L) through 2012, and average mdl = 0.019 mg per L from 2013 to 2019 (range = 0.005-0.056 mg per L);

K: determined by optical emission using a Jobin Yvon Ultima II Inductively Coupled Plasma Spectrometer through November 2012, and by optical emission using a Thermo Fisher iCAP 6300 starting in December 2012; average mdl = 0.024 mg per L (range = 0.009-0.045 mg per L) through 2012, and average mdl = 0.005 mg per L from 2013 to 2019 (range = 0.001-0.018 mg per L);

Mg: determined by optical emission using a Jobin Yvon Ultima II Inductively Coupled Plasma Spectrometer through November 2012, and by optical emission using a Thermo Fisher iCAP 6300 starting in December 2012; average mdl = 0.018 mg per L (range = 0.003-0.053 mg per L) through 2012, and average mdl = 0.004 mg per L from 2013 to 2019 (range = 0.001-0.008 mg per L);

Na: determined by optical emission using a Jobin Yvon Ultima II Inductively Coupled Plasma Spectrometer through November 2012, and by optical emission using a Thermo Fisher iCAP 6300 starting in December 2012; average mdl = 0.028 mg per L (range = 0.005-0.106 mg per L) through 2012, and average mdl = 0.008 mg per L from 2013 to 2019 (range = 0.001-0.014 mg per L);

DOC: performed using the catalytically-aided platinum 680°C combustion technique for sample oxidation on a Shimadzu DOC-VCPH TN analyzer through October 2016, and by using the catalytically-aided platinum 680°C combustion technique for sample oxidation on a Shimadzu DOC-VCPH TNM-1 analyzer starting in November 2016; average mdl = 0.036 mg per L (range = 0.011-0.096 mg per L) through October 2016, and average mdl = 0.036 mg/L from November 2016 through 2019 (range = 0.030-0.041 mg per L);

Br: determined by Micro-membrane Suppressed Ion Chromatography, using an AS 18 column, on a Dionex Ion Chromatograph ICS2500; average mdl = 0.003 mg per L (range = 0.001-0.008 mg per L);

SO4: determined by Micro-membrane Suppressed Ion Chromatography, using an AS 18 column, on a Dionex Ion Chromatograph ICS2500; average mdl = 0.008 mg per L (range = 0.001-0.062 mg per L);

PO4: determined by Micro-membrane Suppressed Ion Chromatography, using an AS 18 column, on a Dionex Ion Chromatograph ICS2500; average mdl = 0.007 mg per L (range = 0.002-0.023 mg per L); and

SiO2: determined by Ammonium Molybdate reaction and reduction with Ascorbic Acid, using an Astoria 2 Autoanalyzer; 2012 mdl = 0.002 mg per L.
Methodology_Citation:
Methodology_Citation:
Methodology_Citation:

Methodology:

Methodology_Type: Field
Methodology_Description:: WATER TABLE:

A network of 24 non-recording wells was installed in WS77 on the Santee Experimental Forest between February 1963 and January 1964. Unfortunately we do not know the exact location of these original 24 wells, but the distribution of the wells was proportional to that of the soil types across the watershed. Monitoring of these wells was discontinued in 1971. These 24 original wells were constructed using 1.5 inch diameter iron pipe with 0.25 to 0.375 inch holes drilled on all sides allowing for adequate equalization of water in each well. These wells were installed to a depth of 20 ft below ground surface, using a minute-man drill. One foot of each pipe was left protruding above ground surface, and tin cans were used to cap each well.

Another set of 42 non-recording wells were installed on WS77 in 1992 (concurrent with the installation of a similar network on Watershed 80), two years after Hurricane Hugo had devastated the SEF in September 1989. Likely these wells were added to enhance monitoring capabilities after the hurricane. This network was monitored manually until early 1995, and recording data logger/sensor units were installed in a subset of wells in December 1996 (a WL40 unit installed in 1996 near the present location of Well J, but there are problems with most of that data because the physical reference point from which the instrument was recording its measurements is unclear, and therefore those data are not included in this data publication). These 42 wells were constructed with 1.5 inch diameter PVC pipe and were installed to a depth of 8-10 ft (or more) below ground surface.

Wells were visited approximately every two weeks and the distance from the top of the well to the water surface was measured with a steel tape and pen flashlight or similar measuring device (such as a Hydrolite).

WELL J -

On February 15, 2005 Well J was installed using a manufactured Blue Tip well point, extended to 3.05 meters (m) in length using 3.8 centimeter (cm) diameter PVC pipe, following standard installation procedures. An auger was used to bore a hole approximately 7.6 centimeters (cm) in diameter, the screen and riser pipe were placed into the hole, and a gravel pack was added around the pipe along the screened section and up to about 15 cm below the ground surface. Bentonite clay was added to the top 15 cm of the bore hole as a seal to prevent percolation of surface water. Total well depth was approximately 3.05 m below ground surface. Well J is located in Wahee soil in an area that will be clearcut and replanted with Longleaf pine seedlings.

A Global Water WL15 pressure transducer (data logger and linked sensor) was immediately installed in the well, and the data logger was set to record water level every hour.

The well was visited approximately every two weeks and the most recently acquired data were downloaded from the data logger to a laptop computer using Global Logger software. Water level readings were manually checked by using a Hydrolite device inside the well after removing the WL15 unit. Starting in May 2009 this measurement was performed using a Solinst Mini 101 water level meter.

02/28/2005 Data logger removed for calibration.
03/02/2005 Data logger reinstalled.
03/10/2005 Well purged.
04/12/2005 Batteries failed as well as cable partially unwound.
05/05/2005 Batteries replaced and cable wound.
10/10/2005 Battery failure.
10/13/2005 Batteries replaced.
06/08/2007 Data logger removed for prescribed fire.
06/11/2007 Reinstalled data logger.
04/21/2009 Data logger removed for prescribed fire.
04/22/2009 Reinstalled data logger.
01/05/2010 Battery failure.
01/06/2010 Batteries replaced.
05/20/2010 Battery failure and replacement.
07/27/2010 Data logger failed.
08/10/2010 Data logger replaced.
03/01/2013 Data logger removed for prescribed fire.
03/06/2013 Data logger reinstalled on 03/06/2013 (but recording interval was not changed back to hourly from daily).
03/20/2013 The above oversight was corrected and the recording interval was reset to hourly.
01/21/2016 Data from 01/21/2016 to 02/19/2016 probably unusable because of drift.
02/11/2016 Recalibrated data logger.
02/19/2016 Replacement WL16 (with USB port) installed.
04/18/2016 Data logger removed from well in advance of WS77 prescribed burn.
04/20/2016 Reinstalled data logger.

Excessive drift observed in WL16 readings from early 2012 through February 2016; data through 2015 during this period was corrected using equations derived by regressing biweekly internal manual measurements of water level against the WL16 readings. For the 2016 data through 02/02/2016, data were corrected by using equations derived by regressing corrected WL16 values on WL40 readings collected every 4 hours between 10/24/2015 and 12/31/2015 to predict WL16 data, then interpolating between the 4-hour predictions.

For the below periods the following regression equations were employed:
02/19/2012 13:00 to 12/31/2012 23:00 Manual = 1.005*WL16 - 0.118 R2 = 0.99 Range of differences = 1.0 to 24.2 cm n = 22
01/01/2013 00:00 to 12/31/2013 23:00 Manual = 1.053*WL16 - 0.521 R2 = 0.99 Range of differences = 0.1 to 10.2 cm n = 24
01/01/2014 00:00 to 12/31/2014 23:00 Manual = 1.045*WL16 - 0.449 R2 = 0.99 Range of differences = 0.1 to 9.0 cm n = 23
01/01/2015 00:00 to 12/31/2015 23:00 Manual = 1.115*WL16 - 1.103 R2 = 0.99 Range of differences = 0.1 to 9.6 cm n = 24
01/01/2016 00:00 to 02/02/2016 08:00 WL16 = 1.015*WL40 - 0.279 R2 = 0.99
04/06/2017 Recalibrated data logger.
08/25/2017 Data logger started malfunctioning. Data removed through 12/15/2017.
12/15/2017 Replaced WL16. New sensor length = 13.22 ft.
03/09/2018 Removed data logger for prescribed fire.
03/13/2018 Reinstalled data logger.
05/09/2018 Re-measured the length of sensor = 13.22 ft. Re-measured the length of pipe above ground = 4.06 ft.
06/21/2018 Recalibrated data logger.
07/10/2018 Recalibrated data logger.
08/10/2018 Recalibrated data logger.
09/07/2018 Recalibrated data logger.
10/03/2018 Data logger will not calibrate. Removed for repair.
10/04/2018 Replaced WL16. New sensor length = 13.23 ft.
03/25/2019 Recalibrated data logger.
06/13/2019 Recalibrated data logger.
10/02/2019 Recalibrated data logger.
11/07/2019 Recalibrated data logger.

WELL K -

Well K was installed using a manufactured Blue Tip well point, extended to 3.05 meters (m) in length using 3.8 centimeter (cm) diameter PVC pipe, following standard installation procedures. An auger was used to bore a hole approximately 7.6 cm in diameter, the screen and riser pipe were placed into the hole, and a gravel pack was added around the pipe along the screened section and up to about 15 cm below the ground surface. Bentonite clay was added to the top 15 cm of the bore hole as a seal to prevent percolation of surface water. Total well depth was approximately 3.05 m below ground surface. On July 13, 2016, a Global Water WL16 pressure transducer (data logger and linked sensor) was immediately installed in the well, and the data logger was set to record water level every hour. Well K is located in a riparian zone that will not be harvested.

The well was visited approximately every one month and the most recently acquired data were downloaded from the data logger to a laptop computer using Global Logger software. Water level readings were manually checked by using a Solinst Mini 101 water level meter.

07/13/2016 WL16 installed. Length of sensor = 10.55 ft. Length of pipe above ground = 4.15 ft. Measurement interval = 1 hour.
01/19/2018 Recalibrated data logger.
03/09/2018 Data logger removed for prescribed fire.
03/13/2018 Removed data logger for prescribed fire.
05/03/2018 Recalibrated data logger.
05/09/2018 Re-measured the length of sensor = 10.60 ft. Re-measured the length of pipe above ground = 4.15 ft. Recalibrated datalogger.
11/21/2018 Recalibrated data logger.
06/13/2019 Recalibrated data logger.
07/11/2019 Recalibrated data logger.

NEW WELLS -

Four additional wells, equipped with Global Water WL16 pressure transducers were installed in 2018, in advance of the 2020 harvest to convert the watershed from Loblolly pine to Longleaf pine. The locations of the wells were selected by distributing them in each type of harvesting treatment and type of soil. Well 2 was installed in Craven soil in an area that will be thinned to 15 square meters per hectare (m²/ha). Well 12 was installed in Wahee soil in an area that will be thinned to 15 m²/ha. Well 92 was installed in Craven soil in an area that will be clearcut and replanted with Longleaf pine seedlings. Well 93 was installed in Wahee soil in an area that will be harvested by a group selection method to 15 m²/ha and replanted with Longleaf pine seedlings.

WELL 2 -

Well 2 was installed using a manufactured Blue Tip well point, extended to 3.05 m in length using 3.8 cm diameter PVC pipe, following standard installation procedures. An auger was used to bore a hole approximately 7.6 cm in diameter, the screen and riser pipe were placed into the hole, and a gravel pack was added around the pipe along the screened section and up to about 15 cm below the ground surface. Bentonite clay was added to the top 15 cm of the bore hole as a seal to prevent percolation of surface water. Total well depth was approximately 3.05 m below ground surface. On July 13, 2016, a Global Water WL16 pressure transducer (data logger and linked sensor) was immediately installed in the well, and the data logger was set to record water level every hour.

The well was visited approximately every one month and the most recently acquired data were downloaded from the data logger to a laptop computer using Global Logger software. Water level readings were manually checked by using a Solinst Mini 101 water level meter.

08/10/2018 WL16 installed. Length of sensor = 12.55 ft. Length of pipe above ground = 4.00 ft. Measurement interval = 1 hour.
09/7/2018 Recalibrated datalogger.
11/21/2018 Recalibrated datalogger.
05/07/2019 Recalibrated datalogger.
06/13/2019 Recalibrated datalogger.

WELL 12 -

Well 12 was installed using a manufactured Blue Tip well point, extended to 3.05 meters (m) in length using 3.8 centimeter (cm) diameter PVC pipe, following standard installation procedures. An auger was used to bore a hole approximately 7.6 cm in diameter, the screen and riser pipe were placed into the hole, and a gravel pack was added around the pipe along the screened section and up to about 15 cm below the ground surface. Bentonite clay was added to the top 15 cm of the bore hole as a seal to prevent percolation of surface water. Total well depth was approximately 3.05 m below ground surface. On July 13, 2016, a Global Water WL16 pressure transducer (data logger and linked sensor) was immediately installed in the well, and the data logger was set to record water level every hour.

The well was visited approximately every one month and the most recently acquired data were downloaded from the data logger to a laptop computer using Global Logger software. Water level readings were manually checked by using a Solinst Mini 101 water level meter.

08/13/2018 WL16 installed. Length of sensor = 11.70 ft. Length of pipe above ground = 4.87 ft. Measurement interval = 1 hour.
09/07/2018 Recalibrated datalogger.
11/21/2018 Recalibrated datalogger.
03/25/2019 Recalibrated datalogger.
06/13/2019 Recalibrated datalogger.
07/11/2019 Recalibrated datalogger.

WELL 92 -

Well 92 was installed using a manufactured Blue Tip well point, extended to 3.05 meters (m) in length using 3.8 centimeter (cm) diameter PVC pipe, following standard installation procedures. An auger was used to bore a hole approximately 7.6 cm in diameter, the screen and riser pipe were placed into the hole, and a gravel pack was added around the pipe along the screened section and up to about 15 cm below the ground surface. Bentonite clay was added to the top 15 cm of the bore hole as a seal to prevent percolation of surface water. Total well depth was approximately 3.05 m below ground surface. On July 13, 2016, a Global Water WL16 pressure transducer (data logger and linked sensor) was immediately installed in the well, and the data logger was set to record water level every hour.

The well was visited approximately every one month and the most recently acquired data were downloaded from the data logger to a laptop computer using Global Logger software. Water level readings were manually checked by using a Solinst Mini 101 water level meter.

08/10/2018 WL16 installed. Length of sensor = 11.62 ft. Length of pipe above ground = 4.68 ft. Measurement interval = 1 hour.
10/03/2018 Recalibrated datalogger.

WELL 93 -

Well 93 was installed using a manufactured Blue Tip well point, extended to 3.05 meters (m) in length using 3.8 centimeter (cm) diameter PVC pipe, following standard installation procedures. An auger was used to bore a hole approximately 7.6 cm in diameter, the screen and riser pipe were placed into the hole, and a gravel pack was added around the pipe along the screened section and up to about 15 cm below the ground surface. Bentonite clay was added to the top 15 cm of the bore hole as a seal to prevent percolation of surface water. Total well depth was approximately 3.05 m below ground surface. On July 13, 2016, a Global Water WL16 pressure transducer (data logger and linked sensor) was immediately installed in the well, and the data logger was set to record water level every hour.

The well was visited approximately every one month and the most recently acquired data were downloaded from the data logger to a laptop computer using Global Logger software. Water level readings were manually checked by using a Solinst Mini 101 water level meter.

10/18/2018 WL16 installed. Length of sensor = 12.04 ft. Length of pipe above ground = 4.62 ft. Measurement interval = 1 hour.

To find additional data (e.g., spatial) for Santee Experimental Forest go to: https://www.srs.fs.usda.gov/charleston/santee/

Methodology:

Methodology_Type: Field
Methodology_Description:: WEATHER:

WS77 non-recording gauges -

A network of five non-recording gauges was established inside and around the perimeter of WS77 in September 1963, and collection of rainfall data began in December 1963. Four rain gauges were installed around the watershed boundary (numbers 1-4), and one was installed in a central location within the watershed (number 5). From 1963 to 1984 rainfall data were collected sporadically (usually just after a recent rainfall event, and not on weekends or holidays) using manual rain gauges.

Met 5 data -

From 1963 to 1966, and then again from 1989 to 1996, rainfall data were collected sporadically (usually just after a recent rainfall event) using a manual rain gauge. A Belfort Universal Recording Rain Gauge that recorded rainfall on strip charts was also used from 08/25/1993 to 02/08/1996.

Starting in February 1996 both air temperature and rainfall were recorded electronically by sensors linked to an Omnidata 800 data logger and downloaded via data storage packs.

At the same time that filled data storage packs were collected (and replaced by new, empty packs), the manual rain gauge water level was recorded using a dipstick and then dumped. Maximum/minimum and current ambient air temperature were also recorded (at 1.40 meters (m) inside a ventilated wooden enclosure).

Starting in September 2001 both instantaneous hourly air and soil temperature and rainfall were recorded electronically by sensors linked to Onset Hobo data loggers and downloaded directly to a laptop computer in the field.

The Onset Hobo H08-002-02 Temperature/External Channel data logger equipped with a 0.10 m (4-inch) wire air temperature sensor (at a height of 1.27 m inside a ventilated wooden enclosure) and linked to a TMC6-HD soil temperature sensor was used to monitor instantaneous hourly air and soil temperatures from 09/13/2001 to 07/29/2009. Data were downloaded to a laptop computer using BoxCar Pro software. This data logger was replaced by an Onset Hobo U12 4-Channel External data logger linked to a TMC1-HD air temperature sensor and a TMC6-HD soil temperature sensor on 07/29/2009. Data were downloaded to a laptop computer using Hoboware software.

Rainfall was recorded by an Onset RG2M tipping bucket rain gauge (with its opening 0.60 m above the ground) linked to an Onset Hobo H7 Event data logger.

The manual rain gauge water level was recorded using a dipstick and then dumped. Max/min and current ambient air temperature were also recorded (at a height of 1.40 m inside a ventilated wooden enclosure).

The Hobo H7 Event data logger was replaced with a Hobo UA-003-64 Pendant data logger on 12/11/2014.

The TMC1-HD air temperature sensor began exhibiting anomalies on 06/14/2015 and was replaced by another TMC1-HD unit on 06/24/2015.

The aging wooden temperature sensor enclosure was replaced on 04/21/2016. On 04/27/2016, a new TMC6-HD soil temperature sensor was installed.

The TMC1-HD air temperature sensor was replaced on 05/02/2018.

We replaced the malfunctioning Pendant data logger with another Hobo H7 Event data logger on 09/11/2018 in advance of Hurricane Florence.

Process_Step:

Process_Description:: STREAMFLOW:

Until September 1995, ADR tapes were removed and the 15-minute stage data translated (either by hand or by a photoelectric tape reader) and then converted into daily mean flow rates using these data with the stage-discharge relationship for the weir in a Fortran program.

Starting in September 1995, 15-minute stage data were downloaded from the Teledyne-ISCO 3210 flow logger to a computer in the field. Downloaded stage data were post-processed (removing spurious data, such as download artifacts) and prepared for runs with SAS software to generate 15-minute (or 10-minute) flow rates using the established stage-discharge relationship for the weir.

Daily total flow was calculated by averaging flow rates over the individual recording intervals, multiplying the average rate by the appropriate time factor for the interval and then summing interval flows for each day. Values in liters were then converted to cubic meters.

Predicting Streamflow for Special Cases:

4210 stage data from 10/24/2008 18:30 to 10/25/2008 17:00 (during an extremely large flow event) were predicted using data from a GL400 backup logger/pressure transducer and the following regression equation:
ISCO 4210 = GL400*0.97 - 1.42 (R2 = 0.99)

This equation was derived by regressing 4210 stage data on GL400 stage data for the remainder of the month of October 2008.

Extreme rainfall event on October 3-4, 2015 (and also large amounts of rain on the days before and after) led to record flow levels on the Santee Experimental Forest watersheds. The ultrasonic sensor was briefly submerged during this event, but data from a backup GL400 logger and pressure transducer were available to help predict the missing stage values. Data from 10/01/2015 0:00 through 10/03/2015 21:00 and then 10/05/2015 4:00 through 10/09/2015 21:00 were used to generate the following regression equation for October 3-4:
ISCO 4210 = GL400*1.01 - 1.45 (R2 = 0.99)

Stage values around the peak of the highest flows exceeded the earlier established range of the stage-discharge equation for the WS77 weir (0 to 4.26 ft above the v-notch), and there was also some flow escaping around the weir through an opening in one of the side weir walls. Accurate flow values during these periods were therefore not available and were left as blank values.

Hurricane Matthew on October 7-8, 2016 caused very high flow levels on the Santee Experimental Forest. The ultrasonic sensor was briefly submerged during this event, but data from a backup GL500 logger and pressure transducer were available to help predict the missing stage values. Data from 10/07/2016 4:30 to 10/08/2016 1:00 were used to generate the following regression equation for use in estimating stage values during the rising limb of the event:
ISCO 4210 = GL500*0.97 - 1.19 (R2 = 0.99)

Data from 10/08/2016 14:30 to 10/11/2016 8:00 were used to generate the following regression equation for use in estimating stage values during the falling limb:
ISCO 4210 = GL500*0.99 - 1.22 (R2 = 0.99)

Stage values around the peak of the highest flows exceeded the range of the stage-discharge equation for the WS77 weir, and there was also some flow around the weir through an opening in one of the side weir walls.

For an unknown reason the ultrasonic sensor stopped communicating with the new Signature Flow Meter from 11/24/2018 16:45 to 11/26/2018 13:00, and therefore data from the backup GL500 logger and pressure transducer were used to generate the following regression equation in order to predict the missing stage data:
Signature FM = GL500*1.01 - 1.24 (R2 = 0.99)

On 1/26/19 21:30 the level sensor reading became "stuck" and the system had to be reset on 1/28/19. Corrections to the stage data during the 1/26/19 21:45 to 1/28/19 12:30 period were again made by regressing Signature FM data on backup GL500 pressure transducer data:
Signature FM = GL500*0.93 - 1.11 (R2 = 0.95)

On 8/23/19 14:45 the level sensor reading again became stuck and the system was reset on 8/26/19. Corrections to the stage data during the 8/23/19 15:00 to 8/26/19 9:00 period were again made by regressing Signature FM data on backup GL500 pressure transducer data:
Signature FM = GL500 - 1.29 (R2 = 0.99)
Process_Date: Unknown

Process_Step:

Process_Description:: WATER QUALITY:

Data collected in the field or during laboratory analyses were recorded into electronic spreadsheets and checked for missing values and/or outliers.

For the sake of consistency, data reported for SO4 during the 1989-1994 period have been adjusted to reflect the concentration of SO4-S.

Data (in the form of concentrations obtained from the laboratory) were entered into Microsoft Excel spreadsheets and checked for missing values and/or outliers.

For the purposes of this database, analyte concentrations registering below the method detection limit (mdl) prior to March 2007 were assigned the value of the respective mdl.

Starting in March 2007, analyte concentrations were posted as received from the Coweeta Hydrologic Laboratory except in the case of obvious contamination or negative values. Occasional negative values (sometimes observed for analytes such as Total Phosphorus or Mg) were assigned the value "0.001" according to the established practice at the Coweeta Hydrologic Laboratory.
Process_Date: Unknown

Process_Step:

Process_Description:: WATER TABLE:

Water level information in \Data\WS77_well_levels_1964-1995.csv was retrieved from field notebooks and recorded in databases (written and electronic) at the office. Using information about the height of individual wells above ground surface allowed for calculation and plotting of water table level below ground surface.

Water level data in \Data\WS77_well_levels_2005-2017.csv was transferred to an electronic database at the office. Using information about the height of the well above ground surface and its elevation relative to mean sea level allowed for calculation and plotting of water table level below ground surface (in centimeters) and relative to mean sea level (in meters).

Ground surface elevation of Well J is 9.6748 meters (m) above sea level (asl), and ground surface elevation of Well K is 6.43 m asl.
Process_Date: Unknown

Process_Step:

Process_Description:: WEATHER:

WS77 non-recording gauges -

Rainfall amounts were recorded for each gauge in the network, and if fairly similar they were averaged to obtain an overall average estimate of rainfall in WS77. However, if unequal distribution of rainfall was observed, the Thiessen or isohyetal method was employed to obtain a realistic average value.

The original units for rainfall were inches; for the sake of later consistency the data have been converted to millimeters.

Met 5 data -

Prior to the introduction of electronic measurements, rainfall data recorded in the field were plotted and visually compared with data from other stations.

Back at the office the hourly electronic data were retrieved from the data storage pack and plotted to check for outliers. Daily maximum and minimum air temperatures were then obtained from the hourly data and used to calculate the daily average air temperature (using Program SAS).

Back at the office the electronic data were retrieved from the laptop computer and plotted to check for outliers or anomalies. The tipping bucket gauge totals were calibrated against the amount of rainfall that had been collected in the manual gauge (the expected amount of rainfall recorded by each "tip" was adjusted by a factor corresponding to the total amount of rain collected in the manual gauge divided by the total recorded by the tipping bucket gauge for each download interval).

Pivot tables in Excel spreadsheets were used to convert the adjusted event-based rainfall data into hourly totals.

The times for instantaneous temperature data were not always recorded "on the hour", so these were adjusted to synchronize with the closest hourly rainfall data. The difference was usually no more than 15 minutes.

Lotti Road tipping bucket data were used to estimate missing tips between 09/05/2014 and 09/10/2014, on 11/01/2014, between 11/20/2014 and 12/09/2014, and between 09/05/2018 and 09/10/2018.
Process_Date: Unknown

Process_Step:

Process_Description:: All missing data were originally assigned the value "-9999"; during database development these values were set to blank values.
Process_Date: 2019

Process_Step:

Process_Description:: This data package was updated and the following data were added:

2018 and 2019 water table data for Well J and K were added. Four new wells were installed in WS77 in 2018: Well 2, Well 12, Well 92 and Well 93. Data for 2018 and 2019 for these new wells were added. See detailed information for each well in the methodology section.

2018 WS 77 water quality data for a few outliers (see completeness report section) were removed.

2019 15-minute flow rate and daily flow data from the WS77 stream gauging station were added.

2019 WS77 water quality data were added.

2019 hourly air and soil temperature and rainfall data from the Met 5 weather station were added.
Process_Date: 2020

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Overview:: FILES DESCRIBED BELOW ARE AVAILABLE THROUGH FULL DATA PUBLICATION DOWNLOAD.

Data are available as comma-delimited ASCII text files. Data are also available as tab-delimited files through the online query tool which also provides the ability to calculate summary statistics, but be aware that those calculations are based on user selections and should be carefully interpreted.

\DATA\FLOW\

WS77_10-15min_flow_2003-2019.csv: 10 or 15 minute instantaneous flow rate data at the WS77 weir starting in 2003.
Location = watershed name (WS77 = Watershed 77)
Instr_ID = gauging station name (Weir77 = water level recorder used in conjunction with WS77 weir)
Date_time = instantaneous date and time stage data recorded (format MM/DD/YYYY hh/mm)
Date = date associated with stage data (format MM/DD/YYYY)
Time24_Flo = nearest minute associated with stage data (0 to 1425 or 1430)
Flow_liter = 10 or 15 minute flow rate, in liters per second (L/sec)

WS77_daily_flow_1964-2000.csv: Daily mean flow rate data from 1964 to 2000.
Location = watershed name (WS77 = Watershed 77)
Instr_ID = gauging station name (Weir77 = water level recorder used in conjunction with WS77 weir)
Date = date associated with stage data (format MM/DD/YYYY)
Dailyflow = daily mean flow rate, in L/sec

WS77_daily_flow_2003-2019: WS77 daily mean flow rate and total daily flow data starting in 2003.
Location = watershed name (WS77 = Watershed 77)
Instr_ID = gauging station name (Weir77 = water level recorder used in conjunction with WS77 weir)
Date = date associated with stage data (format MM/DD/YYYY)
Avg_FlowRa = daily mean flow rate, in L/sec
DailyFlow = daily total flow, in cubic meters (m³)

\DATA\WATER_QUALITY\

WS77_water_chemistry_1976-1994.csv: Historic WS77 daily water quality data collected approximately weekly from 1976 to 1982 and 1989 to 1994.
Location = watershed name (WS77 = Watershed 77)
Instr_ID = gauging station name (Weir77 = WS77 weir)
Date = date associated with water chemistry data (format MM/DD/YYYY)
pH = stream pH
NO3_NO2_N_mgL = nitrogen concentration in the form of nitrate/nitrite, in mg/L
NH4_N_mgL = nitrogen concentration in the form of ammonium, in mg/L
PO4_P_mgL = phosphorus concentration in the form of phosphate, in mg/L
Cl_mgL = chloride concentration, in mg/L
K_mgL = potassium concentration, in mg/L
Na_mgL = sodium concentration, in mg/L
Ca_mgL = calcium concentration, in mg/L
Mg_mgL = magnesium concentration, in mg/L
SO4_S_mgL = sulfur concentration in the form of sulfate, in mg/L
TKN_mgL = total Kjeldahl nitrogen concentration, in mg/L
SiO3_mgL = silicate concentration, in mg/L
HCO3_mgL = bicarbonate concentration, in mg/L
TDN_mgL = total dissolved nitrogen concentration, in mg/L

WS77_water_chemistry_2003-2019.csv: Water quality and physical property data recorded from WS77 gauging station starting in March 2003, during periods of active flow.
Location = watershed name (WS77 = Watershed 77)
Instr_ID = gauging station name (Weir77 = WS77 weir)
Date_time = instantaneous date and time water sample collected or multiprobe reading obtained (format MM/DD/YYYY HH:MM)
Date = date sample collected or multiprobe reading obtained (format MM/DD/YYYY)
Sample_type = Sample type (grab, automated or Manta/Hanna multiprobe measurement)
TDN_mgL = total dissolved nitrogen concentration, in milligrams per liter (mg/L)
TDP_mgL = total dissolved phosphorus concentration, in mg/L
NH4_N_mgL = nitrogen concentration in the form of ammonium, in mg/L
NO3_NO2_N_mgL = nitrogen concentration in the form of nitrate/nitrite, in mg/L
Cl_mgL = chloride concentration, in mg/L
Ca_mgL = calcium concentration, in mg/L
K_mgL = potassium concentration, in mg/L
Mg_mgL = magnesium concentration, in mg/L
Na_mgL = sodium concentration, in mg/L
P_mgL = phosphorus concentration, in mg/L
DOC_mgL = dissolved organic carbon concentration, in mg/L
Br_mgL = bromide concentration, in mg/L
SO4_mgL = sulfate concentration, in mg/L
PO4_mgL = orthophosphate concentration, in mg/L
SiO2_mgl = silicate concentration, in mg/L
Temp_C = stream temperature, in °C
pH = stream pH
Conductivity = specific conductance, in milliSiemens/centimeter (mS/cm)
Salinity_P = salinity (Practical Salinity Scale)
DO_mgL = dissolved oxygen, in mg/L
DO_per_sat = percent saturation dissolved oxygen in stream (%)

\DATA\WATER_TABLE\

WS77_well_levels_1964-1995.csv: Daily well level data for manual well networks in WS77 (pre- and post-Hurricane Hugo) from 1964 to 1971 and 1992 to 1995.
Location = watershed name (WS77 = Watershed 77)
Instr_ID = well name (w17701 = pre-Hugo well number 1; see note below)
Date = date associated with water table data (format MM/DD/YYYY)
Depth_cm_b = depth, cm below ground surface, in cm (positive values represent levels above ground surface and negative values represent levels below ground surface)
elev_m_asl = elevation, in meters above sea level

Note: The form of the well ID numbers is whwwnn, where h is an indicator of pre Hurricane Hugo versus post Hurricane Hugo, ww is the watershed number, and nn is the well number. The values of h are 1 for pre Hugo, and 2 for post Hugo. The well numbers, nn, are in two digit format, e.g. well numbers less than 10 are represented as 0n, as opposed to just n.

WS77_well_levels_2005-2019.csv: Hourly well level data recorded from well J starting in 2005, from well K in 2016, and from wells 2, 12, 92, and 93 starting in 2018.
Location = watershed name (WS77 = Watershed 77)
Instr_ID = instrument name (Well J = data logger/sensor unit in Well J, Well K = data logger/sensor unit in Well K)
Date_time = instantaneous date and time associated with water table data (format MM/DD/YYYY HH:MM)
Date = date associated with water table data (format MM/DD/YYYY)
Time24_ = nearest hour associated with water table data (0:00 to 23:00), in hours
Depth_cm_b = depth, cm below ground surface, in cm (positive values represent levels above ground surface, negative values represent levels below ground surface
elev_m_asl = elevation, in meters above sea level
Sample_Int = sample interval, in hours
Remarks = additional notes or remarks (when depths below ground surface and elevations above mean sea level for periods where the water table was below the detection limit of the sensor, this column contains "DRY" and both Depth_cm_b and elev_m_asl are blank)

\DATA\WEATHER\

Met5_daily_data_1963-2000.csv: Daily temperature and rainfall data from the Met 5 weather station in WS77 from mid-December 1963 to early January 2001.
Location = watershed name (WS77 = Watershed 77)
Instr_ID = weather station name (Met5 = Met 5 weather station)
Date = date associated with rainfall and air temperature data (format MM/DD/YYYY)
Rainfall_m = daily total rainfall, in millimeters (mm)
Air_Temp_C = daily average temperature, in degrees Celsius (°C)

Met5_hourly_data_2001-2019.csv: Hourly air and soil temperature and rainfall data recorded at Met 5 weather station in WS77 starting in mid-September 2001.
Location = watershed name (WS77 = Watershed 77)
Instr_ID = weather station name (Met5 = Met 5 weather station)
Date = date associated with air and soil temperature data (format MM/DD/YYYY)
Time24 = nearest hour associated with air and soil temperature data (0:00 to 23:00)
Date_time_temp = date and time that instantaneous air and soil temperature data were recorded (format MM/DD/YYYY HH:MM)
Air_Temp_C = instantaneous air temperature, in °C
Soil_Temp_ = instantaneous soil temperature, in °C
Date_time_rain = ending date and time for calculation of hourly rainfall (format MM/DD/YYYY HH:MM)
Rainfall_m = rainfall total for preceding hour, in mm

WS77_nonrecording_gauges_1963_1984.csv: WS77 non-recording gauge daily rainfall data, December 1963 through May 1984. This network of rain gauges on WS77 was checked sporadically (the purpose of the network was to obtain a better estimate of rainfall on the watershed).
Location = watershed name (WS77 = Watershed 77)
Instr_ID = instrument name (Gauge1, Gauge2, ..., Gauge 5)
Date = date associated with rainfall and air temperature data (format MM/DD/YYYY)
Rainfall_m = daily total rainfall, in mm
Remarks = field notes recorded at time of reading

\SUPPLEMENTS\

SEF_Laboratory_Manual_01-09-14: Portable Document Format (PDF/a) file containing "Santee Experimental Forest: Laboratory Methods" edited by Julie Arnold on 01/09/2014.

wetlab-cookbook_revised-2017-08-08.pdf: Portable Document Format (PDF) file containing "Procedures for Chemical Analysis" by Coweeta Hydrologic Laboratory (obtained on 11/01/2019 from https://www.srs.fs.usda.gov/coweeta/tools-and-data/wetlab-cookbook_revised-2017-08-08.pdf).

WS77_Historic_Rain_Gauges_Map_Date_Unknown.png: Portable Network Graphics file containing a map showing the location of the WS77 1992-1995 manual wells as well as the historic rain gauges.

WS77_Hydrology_Climate_Instrumentation.png: Portable Network Graphics file containing a map showing the location of the WS77 recording wells, meteorologic stations, and weir.
Entity_and_Attribute_Detail_Citation:: none provided

Distribution_Information:

Metadata_Reference_Information:

Metadata_Date: 20240112

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: USDA Forest Service, Southern Research Station, Center for Forested Wetlands Research
Contact_Person: Andy Harrison

Contact_Position: Hydrology Technician

Contact_Address:

Address_Type: mailing and physical
Address: 3734 Hwy 402
City: Cordesville
State_or_Province: SC
Postal_Code: 29434
Country: USA

Contact_Voice_Telephone: 843-336-5603

Contact_Electronic_Mail_Address: charles.a.harrison@usda.gov

Contact Instructions: This contact information was current as of original publication date. For current information see Contact Us page on: https://doi.org/10.2737/RDS.

Metadata_Standard_Name: FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001.1-1999