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Investigation:

ND-02 (Davidson / Stone / Markewitz / Carvalho / Sa / Vieira / Moutinho / Figueiredo)

LBA Dataset ID:

ND02_SOIL_HYDRAULIC_CONDUCT

Originator(s):

1. BELK, E.L.
      2. MARKEWITZ, D.

Point(s) of Contact:

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Dataset Abstract:

Field estimated saturated hydraulic conductivity measurements at the Seca-Floresta km 67 site, in the Tapajos National Forest near Santarem, Para, Brazil, 2001 are provided in this data set. Below-ground observations were obtained by augering 6-cm-diameter vertical holes. Measurements extend to a depth of 4 meters. This activity was a component of the Throughfall Exclusion Experiment.

Beginning Date:

2001-06-12

Ending Date:

2001-06-20

Metadata Last Updated on:

2012-03-29

Data Status:

Archived

Access Constraints:

PUBLIC

Data Center URL:

http://daac.ornl.gov/

Distribution Contact(s):

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Access Instructions:

PUBLIC

Data Access:

IMPORTANT: The LBA-ECO Project website is no longer being supported. Links to external websites may be inactive. Final data products from the LBA project can be found at the ORNL DAAC. Please follow the fair use guidelines found in the dataset documentation when using or citing LBA data.
Datafile(s):

LBA-ECO ND-02 Saturated Soil Hydraulic Conductivity, Tapajos National Forest, Brazil :  http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1075

Documentation/Other Supporting Documents:

LBA-ECO ND-02 Saturated Soil Hydraulic Conductivity, Tapajos National Forest, Brazil :  http://daac.ornl.gov/LBA/guides/ND02_Soil_Hydraulic_Conductivity.html

Citation Information - Other Details:

Belk, E.L. and D. Markewitz. 2012.LBA-ECO ND-02 Saturated Soil Hydraulic Conductivity, Tapajos National Forest, Brazil. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. http://dx.doi.org/10.3334/ORNLDAAC/1075

Keywords - Theme:

Parameter Topic Term Source Sensor
HYDRAULIC CONDUCTIVITY LAND SURFACE SOILS FIELD INVESTIGATION TENSION INFILTROMETER
PERCOLATION TERRESTRIAL HYDROSPHERE GROUND WATER FIELD INVESTIGATION PERMEAMETER

Uncontrolled Theme Keyword(s):  KSAT, PARA, BRAZIL, SATURATED HYDRAULIC CONDUCTIVITY, SOIL PROPERTIES

Keywords - Place (with associated coordinates):

Region
(click to view profile)
Site
(click to view profile)
North South East West
Pará Western (Santarém) km 67 Seca-Floresta Site -2.75000 -2.75000 -55.00000 -55.00000

Related Publication(s):

Belk, Elizabeth L., 2002. Modeling the effects of partial throughfall exclusion on the distribution of soil water in Brazilian Oxisol under tropical moist forest. MS thesis, The University of Georgia. Athens, GA.

Belk, Elizabeth L., Daniel Markewitz, Todd C. Rasmussen, Eduardo J. Maklouf Carvalho, Daniel C. Nepstad, and Eric A. Davidson. 2008. Correction to Modeling the effects of throughfall reduction on soil water content in a Brazilian Oxisol under a moist tropical forest. Water Resour. Res., 44, W07701, doi:10.1029/2008WR007190.

Elizabeth L. Belk, Daniel Markewitz, Todd C. Rasmussen, Eduardo J. Maklouf Carvalho, Daniel C. Nepstad, and Eric A. Davidson. 2007. Modeling the effects of throughfall reduction on soil water content in a Brazilian Oxisol under a moist tropical forest. Water Resources Research, Vol. 43, W08432, doi:10.1029/2006WR005493.

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

Data Description: Field estimated saturated hydraulic conductivity measurements at the Seca-Floresta km 67 site, Santarem, Para, Brazil, 2001. Measurements extend to a depth of 4 meters.



Data are provided as a single comma-delimited ASCII file: ND02_Soil_Hydraulic_Conductivity.csv



Data contents and organization:




Column number,Column heading,Variable Description



1,Date,Sample date (yyyy-mm-dd)


2,Location,Relative location of sampling


3,Depth,Depth of Guelp permeameter in centimeters. Surface indicates surface infiltration ring was utilized and area is 35.2 cm^2. Otherwise depth is depth of auger hole with Guelph tube place at depth.


4,Head_ht,Head height: height of the Guelph permeameter head in centimeters


5,Reading_num,Reading number: number of reading in chronological order (1 to 23)


6,Time,Time: minutes since initiating reading (mm:ss), where 0:00 indicates first reading


7,Time_interval,Time interval: number of minutes (expressed as decimal minutes) elapsed between readings


8,Water_level,Water level: height of water in centimeters (cm) in inner water column of Guelph


9,Water_level_change,Water level change: the change in centimeters during elapsed time interval since last reading


10,Water_level_change_rate,Water level change rate: rate of water level change in centimeters per minute (cm/min) -- the difference in water level divided by the time interval since last measurement.


11,R1,R1: steady-state rate of water change in centimeters per second (cm/sec) estimated from the data


12,Kfs,Kfs: calculated hydraulic conductivity in centimeters per second (cm/sec) based on the measurement date and the reported constants


13,Comments,Specific comments about measurements, if provided; otherwise none.



Note: -9999 indicates missing values where intervals, rates, or saturated hydraulic conductivity could not be calculated.,,,,,,,,,,,,

,,,,,,,,,,,,





Column Column Variable Description

Number Heading

1 Date Sample date (yyyy-mm-dd)

2 Location Relative location of sampling

3 Depth Depth of Guelp permeameter in centimeters. Surface indicates surface infiltration ring was utilized and area is 35.2 cm^2. Otherwise depth is depth of auger hole with Guelph tube place at depth.

4 Head_ht Head height: height of the Guelph permeameter head in centimeters

5 Reading_num Reading number: number of reading in chronological order (1 to 23)

6 Time Time: minutes since initiating reading (mm:ss), where 0:00 indicates first reading

7 Time_interval Time interval: number of minutes (expressed as decimal minutes) elapsed between readings

8 Water_level Water level: height of water in centimeters (cm) in inner water column of Guelph

9 Water_level_change Water level change: the change in centimeters during elapsed time interval since last reading

10 Water_level_change_rate Water level change rate: rate of water level change in centimeters per minute (cm/min) -- the difference in water level divided by the time interval since last measurement.

11 R1 R1: steady-state rate of water change in centimeters per second (cm/sec) estimated from the data

12 Kfs Kfs: calculated hydraulic conductivity in centimeters per second (cm/sec) based on the measurement date and the reported constants

13 Comments Specific comments about measurements, if provided; otherwise none.



Note: -9999 indicates missing values where intervals, rates, or saturated hydraulic conductivity could not be calculated.



Example data records:

Date,Location,Depth,Head_ht,Reading_num,Time,Time_interval,Water_level,Water_level_change,Water_level_change_rate,R1,Kfs,Comments

2001-06-12,Outside Seca plot,Surface,5,1,0:00,-9999,2.3,-9999,-9999,-9999,-9999,none

2001-06-12,Outside Seca plot,Surface,5,2,2:00,2,3.4,1.1,0.55,-9999,-9999,none

2001-06-12,Outside Seca plot,Surface,5,3,4:00,2,4.3,0.9,0.45,-9999,-9999,none

2001-06-12,Outside Seca plot,Surface,5,4,6:00,2,5,0.7,0.35,-9999,-9999,none

2001-06-12,Outside Seca plot,Surface,5,5,8:00,2,5.7,0.7,0.35,-9999,-9999,none

... [Records intentionally omitted.]

2001-06-20,Near soil pit 5,300,10,1,0:00,-9999,16.9,-9999,-9999,-9999,-9999,none

2001-06-20,Near soil pit 5,300,10,2,10:00,10,20.3,3.4,0.340,-9999,-9999,none

2001-06-20,Near soil pit 5,300,10,3,20:00,10,22.7,2.4,0.240,-9999,-9999,none

2001-06-20,Near soil pit 5,300,10,4,30:00,10,25.3,2.6,0.260,-9999,-9999,none

2001-06-20,Near soil pit 5,300,10,5,40:00,10,27.8,2.5,0.250,-9999,-9999,none

2001-06-20,Near soil pit 5,300,10,6,50:00,10,30.3,2.5,0.250,0.00417,0.0003822,none

Data Application and Derivation:

Typical application of data:

The Guelph permeameter is used to generate field measures of saturated hydraulic conductivity. Knowledge of the changes in below-ground storage

and partitioning of water enhances our ability to explain

other responses of the forest to drought conditions. By

quantifying how the ecological functions of tropical forests

change during prolonged drought, we hope to better understand

the changes that may occur during the annual dry

season in functions such as rooting depth or leaf shedding

and better predict the ability of these forests to tolerate

reductions in precipitation associated with land use conversion

as well as long-term climate changes. (Belk, et al. 2006)



Theory of Measurement:

The Guelph permeameter is a standard method for measuring Ksat that is easily accessed in soil physics or hydrology methods texts.



Derivation:

Ksat at surface =(alpha*(G*area*infiltration rate))/(a*(alpha*Height+1)+(depth*alpha)*(3.14159*a))



Ksat at depth= [(0.0041)*(res constant)*(R2)]-[(0.0054)*(res constant)*(R1)]





The following constants were utilized for converting surface measurements to hydraulic conductivity.

alpha=0.12 cm^-1

A=35.44 cm^2

a = 10 cm

H1=7.5 cm

G 0.158

d= 5 cm



The well head height was estimated as WHH=(7.5-I)+WHS where I=insertion depth of cutting ring (=5 cm) and WHS=well head scale value(=5cm). As such well head height = 7.5 cm.

Saturated hydraulic conductivity was calculated for the surface as

Kfs = alpha*(G*A*R1)/a*(alpha*H1+1)+(G*alpha)*(3.14159*a^2)



For subsurface measurements reservoir constants were

X=35.44

Y=2.14

Tube constant used=35.44

And saturated hydraulic conductivity was calculated as

Kfs= [(0.0041)*(tube constant)*(R1 at 10 cm)]-[(0.0054)*(tube constant)*(R1 at 5 cm)]

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

For a few measurements negative Ksat values were obtained. This is not physically possible so re-measurements were made and the negative values discarded.

Process Description:

Data Acquisition Materials and Methods:

Saturated hydraulic conductivity (Ks) was quantified

using a Guelph permeameter [Soil Moisture Equipment

Corporation, 1986]. Seven surface measurements were

made in random locations around the plots using a pressure

infiltrometer attachment. Below-ground observations were

obtained by augering 6-cm-diameter vertical holes.

Measurements extend to a depth of 4 meters. The holes were

gently brushed before measurements to remove any smearing

of the clays that may have occurred during augering.

Three sets of measurements were completed at each of three sites

in the study area.




Data were arithmetically averaged at each depth and assigned to the closest layer midpoint.




The Guelph permeameter is available from Soil Moisture Corp. in Santa Barbara, California, USA.








1 - Outside Seca plot

2 - Near soil pit 5

3 - Above humid (control) plot

4 - Near soil pit 6

5 - Between Seca and humid plot

6 - Outside Seca plot near soil pit 3

7 - Near soil pit 7

8 - Outside of humid plot near soil pit



References:

Belk, Elizabeth L., 2002. Modeling the effects of partial throughfall exclusion on the distribution of soil water in Brazilian Oxisol under tropical moist forest. MS thesis, The University of Georgia. Athens, GA. [LBA-ECO Pub ID #862]




Belk, Elizabeth L., Daniel Markewitz, Todd C. Rasmussen, Eduardo J. Maklouf Carvalho, Daniel C. Nepstad, and Eric A. Davidson. 2007. Modeling the effects of throughfall reduction on soil water content in a Brazilian Oxisol under a moist tropical forest. Water Resources Research, Vol. 43, W08432, doi:10.1029/2006WR005493. [LBA-ECO Pub ID #860]




Belk, Elizabeth L., Daniel Markewitz, Todd C. Rasmussen, Eduardo J. Maklouf Carvalho, Daniel C. Nepstad, and Eric A. Davidson. 2008. Correction to Modeling the effects of throughfall reduction on soil water content in a Brazilian Oxisol under a moist tropical forest. Water Resour. Res., 44, W07701, doi:10.1029/2008WR007190.




Nepstad, D. C., et al. (2002), The effects of partial throughfall exclusion on canopy processes, aboveground production, and biogeochemistry of an Amazon forest, J. Geophys. Res., 107(D20), 8085, doi:10.1029/ 2001JD000360. [LBA-ECO Pub ID # 282]




Sternberg, L. D. S. L., M. Moreira, and D. C. Nepstad (2002), Uptake of water by lateral roots of small trees in an Amazonian tropical forest,Plant Soil, 238, 151 - 158.

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