Database Code: HF026
Title: Hyporheic exchange studies of Watersheds 01 and 03 using saline tracers coupled with electrical resistivity and
hydraulic head data from wells during summer 2010
Abstract:
A series of hyporheic exchange studies were conducted in watersheds 01 and 03 during the summer of 2010 using saline
tracers coupled with electrical resistivity to image the temporal and spatial extent of the hyporheic zone during baseflow
recession. A series of 4 – 48hr tracer tests were conducted in each watershed on a rotational schedule with each tracer
test starting approximately 2 weeks following the start of the previous test in each watershed. Each tracer injection was
targeted to enrich the stream electrical conductivity by ~100 uS/cm. Electrical resistivity surveys were conducted on up to
6 transects of electrodes (12 electrodes per transect) in each watershed for each test. Resistivity surveys were collected,
on a high temporal frequency ranging from continuous to every 4 hrs, for pre-injection, injection, and post-injection until
conductivity measurements in the shallow groundwater well network returned to pre-injection magnitudes. During each
injection conductivity magnitudes were measured in the stream and each accessible groundwater well in the watershed
using a handheld conductivity meter on a frequency ranging from near continuous (~15-30min), during tracer start-up and
shutoff, to every 2-6 hrs depending on position within the tracer test. Hydraulic head data was collected approximately
every 15 minutes by downwell pressure transducers from a select set of groundwater wells in each watershed for nearly
the full summer 2010.
Purpose:
There has been growing interest in the roles that hyporheic zones and riparian zones play in catchment-scale budgets of
nutrients, heat, and energy. Because streams are intimately connected to hyporheic and riparian zones, these
biogeochemical “hot spots”, or zones of enhanced biogeochemical cycling, directly influence water quality of streams.
Significant research has been conducted on the biogeochemical and hydrologic functions of both hyporheic and riparian
zones, though often in isolation from each other. In this proposal, we seek to determine how dynamic valley-bottom
(riparian) hydrology is controlled by valley morphology and gradient, and how this in turn influences hyporheic exchange
throughout summer baseflow recession in headwater catchments. We pose the following research questions:
1) How do the relative magnitudes of down-valley (qDV) and cross-valley (qCV) vectors of riparian subsurface flow
change throughout seasonal baseflow recession?
2) How are these changes controlled by valley-scale morphology and gradient?
3) How spatially consistent (at the reach scale) are the patterns of qDV and qCV?
4) In response to seasonal changes in relative magnitudes of down-valley and cross-valley flow vectors, how does the
extent of hyporheic exchange change during seasonal
baseflow recession?
Geographical Extent:
HJ Andrews Experimental Forest, Western Cascades, Oregon, Watershed 01 and 03. All work was conducted in the
vicinity of the network of shallow groundwater wells installed by Steve Wondzell et al.
Date data commenced: 2010-05-10
Date data terminated: 2010-08-15
Currentness: Ground condition
Progress: Complete
Measurement Frequency: Near-continuous to every 6 hrs depending on measurement.
Update Frequency: None Planned
Completeness Report: Datasets are complete, no planned activities
Principal Investigator: Michael N. Gooseff, Kamini Singha
Other Researchers:
Michael Fitzgerald – Electrical Resistivity Data
Adam Ward – Solute Tracer Data
Tom Voltz – Hydraulic Head Data
Dataset Contact: Michael N. Gooseff
Metadata Contact: Michael Fitzgerald
Theme Keywords: Aquatic ecosystems; Groundwater processes; Stream functions; Hyporheic zone; Riparian
ecosystems; Storms; Subsurface flow; Baseflow
Place Keywords: HJ Andrews Experimental Forest, Watershed 01, Watershed 03
Access: Online
Use Constraint: No restrictions
Database Credit: This work was supported by the National Science Foundation under grant EAR 09-11435.
Cross-References – Publications:
Ward, A.S., Fitzgerald, M., Gooseff, M.N., Voltz, T., Binley A., and Singha, K. (2012). Hydrologic and geomorphic controls on hyporheic
exchange during baseflow recession in a headwater mountain stream. Water Resources Research, 48, W04513, doi:10.1029/2011WR011461,
20 p. (Selected as an AGU Research Spotlight)
Voltz, T., Gooseff, M.N., Ward, A.S., Singha, K., Fitzgerald, M., Wagener, T. (2013). Riparian hydraulic gradient and stream-groundwater
exchange dynamics in steep headwater valleys. Journal of Geophysical Research: Earth Surface, 118(1-17), doi:10.1002/jgrf.20074, 17p.
(Invited Manuscript Submission)
Methodology:
Experimental Design: Electrical resistivity transects set up perpendicular to the stream flow direction used to image the
presence of an electrically conductive tracer in the subsurface, which acts as a proxy for hyporheic exchange extent.
Shallow groundwater wells surrounding the stream reach were used to monitor the hydraulic heads in the wells to
establish hydraulic gradients over a range of conditions during baseflow recession.
Field Methods: Instruments used consisted of: Electrical Resistivity – IRIS Syscal Pro to collect electrical resistivity
values, electrodes were designed and made in-house of PVC pipe and conductive foil material; Solute Concentrations –
YSI handheld device (calibration verification conducted weekly) and small purge pump to make conductivity
measurements in wells, and an FMI pump with a 42 gallon trashcan to do the actual controlled tracer injection, salt was
general feed salt for livestock from 50lb bags; Hydraulic Heads – existing well network installed by Steve Wondzell et al.
outfitted with Onset Computing’s HOBO water level pressure transducers (U20-001-01) in addition to a few Solinst CTD
loggers, calibrations confirmed with Solinst water level tape periodically during the data collection period.
Detailed Entity and Attribute Level Information:
1. Electrical Resistivity Data from Watersheds 01 and 03
General Information for the data set.
Data are contained in separate files for each Watershed (e.g. Watershed 01) and for each tracer injection (e.g. Injection
1). The data are not separated by transect, and each transect contains 323 measurements, where rows 1:323 = Transect
1, rows 324:646 = Transect 2, etc.
For both watersheds, the first tracer injection test contained only 4 transects. All other tracer tests contained 6 transects.
The file ABMN.txt has 4 columns and 323 rows. Column 1 = A, Column 2 = B, Column 3 = M, Column 4 = N and are the
electrode numbers called in for the sequence of resistivity measurements. A, B are the transmitting pair and M, N are the
monitored pair.
Electrode sites are located approximately 20cm below ground surface for all electrodes. Exact locations of the electrodes
can be found in the attached survey data and are referenced in Cartesian space along with the survey locations for the
groundwater monitoring wells in each watershed.
Attribute List:
Attribute Name
DEV
Description
Standard Deviation of Stacked
Primary
Unit of
Data
Measurement
Number
Key
Measure
Type
Scale
Type
N
-
Floating
Ratio
Real
Interval
Real
Measurement
VP
Voltage at Monitored Electrodes
Decimal
N
mV
Floating
Decimal
IN
Current Applied
N
kOhms
Floating
Interval
Real
Decimal
SPA. 5
Transect Identifier
N
Number
Integer
Interval
Real
STACK
# of Times Data Stacked
N
Number
Integer
Interval
Whole
RS-CHECK
Resistance Check
N
kOhms
Floating
Interval
Real
Interval
Real
Interval
Real
Interval
Real
Interval
Real
DateTime
Whole
Decimal
VAB
Voltage Applied to Transmitting
N
V
Electrodes
TX-BAT
Battery Voltage for Transmitting
Decimal
N
V
Electrodes
RX-BAT
Battery Voltage for Receiving
Temperature Inside Resistivity
N
V
Date and Time of Data
Collection
Floating
Decimal
N
Deg. Celsius
Meter
DATE
Floating
Decimal
Electrodes
TEMP.
Floating
Floating
Decimal
Y
MM/DD/YYYY
DateTime
HH:MM:SS
Locations for each groundwater observation well and for all electrodes are contained in the folder “Survey Data and
Hydraulic Head Data” in filename “Land Survey Data_WS01” and “Land Survey Data_WS03”. Maps showing the two
different stream reaches (WS01, WS03) are also contained in the same folder.
See “Attribute_table_VOLTZ” for Metadata description for all data in “Survey Data and Hydraulic Head Data” Folder.