Laboratory and Field Tests of the Sutron RLR-0003-1 

Water Level Sensor

By Janice M. Fulford and R. Scott Bryars

Open File Report 2014–1217

U.S. Department of the Interior

U.S. Geological Survey
ii

U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2014 

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Suggested citation:

Fulford, J.M., and Bryars, R.S., 2015, Laboratory and field tests of the Sutron RLR-0003-1 water level sensor: U.S. 

Geological Survey Open-File Report 2014–1217, 20 p., http://dx.doi.org/10.3133/ofr20141217. 

Any use of trade, firm, or product names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

Although this information product, for the most part, is in the public domain, it also may contain

copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be 

secured from the copyright owner. 

ISSN 2331-1258 
iii

Contents

Abstract ...................................................................................................................................................................... 1

Introduction................................................................................................................................................................. 1

Description of Sensor ................................................................................................................................................. 2

Methods...................................................................................................................................................................... 3

Temperature Testing ............................................................................................................................................... 3

Distance to Water Testing ....................................................................................................................................... 3

SDI-12 Communication Testing............................................................................................................................... 4

Field Testing ........................................................................................................................................................... 4

Results........................................................................................................................................................................ 4

Temperature Testing ............................................................................................................................................... 4

Distance to Water Testing ....................................................................................................................................... 5

SDI-12 Communication Testing............................................................................................................................... 5

Field Testing............................................................................................................................................................ 5

Summary .................................................................................................................................................................... 6

Acknowledgments ...................................................................................................................................................... 6

References Cited........................................................................................................................................................ 7

Figures

[Figures are located at back of report] 

1. Photo of Sutron RLR-0003-1 water level sensor

2. Temperatures applied during temperature testing for three Sutron RLR-0003-1 water level sensors

3. Definition sketch of hydraulic laboratory test measurement variables

4. Air gap applied and water level measured during air gap testing for three Sutron RLR-0003-1 water 

level sensors

5. Difference between initial measured distance to a stationary target made by Sutron RLR-0003-1 (serial 

number 1208558) at room temperature and subsequent measurements made over temperatures from -40 to 

60 degrees Celsius

6. Difference between initial measured distance to a stationary target made by Sutron RLR-0003-1 (serial 

number 1208559) at room temperature and subsequent measurements made over temperatures from -40 to 

60 degrees Celsius

7. Difference between initial measured distance to a stationary target made by Sutron RLR-0003-1 (serial 

number 1208560) at room temperature and subsequent measurements made over temperatures from -40 to 

60 degrees Celsius

8. Difference between the change in air gaps (distance to water) measured by Sutron RLR-0003-1 (serial 

number 1208558) and measured by the references

9. Difference between the change in air gaps (distance to water) measured by Sutron RLR-0003-1 (serial 

number 1208559) and measured by the references

10. Difference between the change in air gaps (distance to water) measured by Sutron RLR-0003-1 (serial 

number 1208560) and measured by the references

11. Differences between the Sutron RLR-0003-1 and the Sutron Accubar bubbler water level system readings 

(top chart) and differences between the Sutron RLR-0003-1 and the Design Analysis Associates (DAA) 

H3613 water level radar (bottom chart) at U.S. Geological Survey streamgaging site 06808500, for the period 

February 28 to July 11, 2013
iv

12. Comparison of the differences between the Sutron RLR-0003-1 radar, Design Analysis Associates (DAA) 

H3613 radar, and wire-weight gage readings plotted with U.S. Geological Survey Office of Surface Water 

(OSW) accuracy requirements

Tables

1. Manufacturer’s specifications for the Sutron RLR-0003-1 water level sensor.. .............................................. 2 

2. Summary statistics for the difference between the Sutron RLR-0003-1 radar reading and the initial Sutron 

RLR-0003-1 radar reading at a stationary target for temperatures within 0.5 degrees Celsius of -40, -20, 0, 

20, 40, and 60 degrees Celsius for serial numbers 1208558, 1208559, and 1208560. Number of data points 

analyzed for each sensor was 898. ............................................................................................................... 4 

3. Test 1 and test 2 summary statistics for the difference between the Sutron RLR-0003-1 radar difference with 

its initial reading and the reference difference with its initial reading. ............................................................ 5

4. Summary statistics for the differences between the Sutron RLR-0003-1 and either the Accubar bubbler 

system or the Design Analysis Associates (DAA) H3613 for the period of February 28 to July 11, 2013...... 6
v

Conversion Factors

Inch/Pound to SI 

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C=(°F-32)/1.8
1

Laboratory and Field Tests of the Sutron RLR-0003-1 

Water Level Sensor

By Janice M. Fulford and R. Scott Bryars

Abstract

Three Sutron RLR-0003-1 water level sensors were tested in laboratory conditions to evaluate 

the accuracy of the sensor over the manufacturer’s specified operating temperature and distance-towater ranges. The sensor was also tested for compliance to SDI-12 communication protocol and in field 

conditions at a U.S. Geological Survey (USGS) streamgaging site. Laboratory results were compared to 

the manufacturer’s accuracy specification for water level and to the USGS Office of Surface Water 

(OSW) policy requirement that water level sensors have a measurement uncertainty of no more than 

0.01 foot or 0.20 percent of the indicated reading. Except for one sensor, the differences for the 

temperature testing were within 0.05 foot and the average measurements for the sensors were within the 

manufacturer’s accuracy specification. Two of the three sensors were within the manufacturer’s 

specified accuracy and met the USGS accuracy requirements for the laboratory distance to water testing. 

Three units passed a basic SDI-12 communication compliance test. Water level measurements made by 

the Sutron RLR-0003-1 during field testing agreed well with those made by the bubbler system and a 

Design Analysis Associates (DAA) H3613 radar, and they met the USGS accuracy requirements when 

compared to the wire-weight gage readings.

Introduction

The U.S. Geological Survey (USGS) Hydrologic Instrumentation Facility (HIF) evaluates the 

performance of hydrologic equipment and instruments used to measure, record, and transmit hydrologic 

data. These devices include sensors used to measure parameters needed to quantify streamflow, water 

quality, and groundwater levels, as well as devices used for data recording, data telemetry, water 

sampling, remote powering of equipment, and measurements from bridges and cableways. Performance 

is evaluated in a variety of ways and includes: 

• the manufacturer’s stated specifications for accuracy, resolution, and temperature operating 

range; 

• any relevant USGS accuracy requirements; 

and may include: 

• compatibility with USGS field hydrologic data-collection communication protocols and 

infrastructure;

• the ability to operate unattended in field conditions; and

• power consumption. 
2

The evaluations may involve the deployment of the device at one or more field locations and usually 

involve testing in controlled laboratory conditions. Evaluations are primarily performed for determining 

if devices are suitable for use by USGS personnel for hydrologic data collection. 

This report describes the methods followed and the results obtained from laboratory and field 

testing of a commercially available, noncontact, radar, water level measuring device, the Sutron RLR0003-1. 

Description of Sensor

The Sutron RLR-0003-1 (fig. 1) is a water level sensor that uses radar to measure the distance 

between the sensor and the water surface. The sensor is manufactured by the Sutron Corporation. A 

radar sensor transmits radio energy to the water surface and multiplies the return of the energy to the 

sensor to compute the distance from the sensor to the water surface. An initial water level, entered after 

installation of the device, is used by the sensor to convert the distance between the sensor and the water 

surface into a water level reading (or stage). The Sutron RLR-0003-1 is weatherproof, and has a fully 

enclosed antenna and Federal Communications Commission part 15 approval. Any terminal emulation 

program can be used with SDI-12 commands to communicate with the sensor. Additional software, 

Sutron RLR Communicator Software, can be downloaded onto a PC computer from the Sutron Web site 

and used with the sensor to help identify whether objects in the radio path are inferring with the 

measurement. Selected manufacturer’s specifications for the sensor are listed in table 1 (Sutron 

Corporation, 2013). 

Table 1. Manufacturer’s specifications for the Sutron RLR-0003-1 water level sensor.

 [in., inches; ABS, American Bureau of Shipping; VDC, volts direct current; mA, milliampere; GHz, gigahertz;

HPBW, half power band width; ft, feet; o

C, degrees Celsius] 

Feature Specification

Housing dimensions 12-in. height, 6.625-in. diameter

Housing material ABS plastic

Weight 6.85 pounds

Communication interfaces SDI-12 and RS232

Power Supply 12 VDC

Current, standby <0.9mA

Current, active <40mA

Frequency 6.6 GHz pulse echo

Beam angle ±16 degrees HPBW

Sampling rate 10 Hertz

Range (distance to water) 5 to 60 ft

Accuracy1 0.01 ft 5–20 ft, 0.05% reading 20–60 ft

Resolution 0.01 ft

Operating temperature range -40 to 60 o

C 

1

(Sutron Corporation, 2013, p. 7).
3

Methods

The Sutron RLR-0003-1 was evaluated by subjecting units to laboratory, SDI-12 

communication, and field testing. Laboratory testing was conducted to evaluate the accuracy of the 

sensor over the manufacturer’s specified operating temperature and distance to water ranges. 

Laboratory results were compared to the manufacturer’s accuracy specification for water level (table 1) 

and to the requirements of the USGS Office of Surface Water (OSW) policy requirement that water 

level sensors have a measurement uncertainty of no more than 0.01 foot (ft) or 0.20 percent of the 

indicated reading (USGS, 1996). SDI-12 communication testing was conducted to evaluate compliance 

with the SDI-12 communication protocol (SDI-12 Support Group, 2012). Field testing was conducted 

by the USGS Iowa Water Science Center at a gaging station to evaluate performance under field 

conditions and to compare sensor measurements with other continuous water level sensors. 

Temperature Testing

Three radar sensors were installed in a walk-in environmental test chamber on a rack and 

pointed horizontally at a stationary target located about 8 ft from the radars. A Design Analysis 

Associates (DAA) H377 temperature sensor was used to measure air temperature. Air temperature and 

radar distance measurements were sampled and logged by a DAA 500 XL logger every 5 minutes. 

Chamber temperatures were manually operated at various intervals and set at temperatures of 0, -40, 20, 

-20, 0, 20, 40, 60, 40, and 20 (fig. 2). The initial distance measurement made at room temperature by a 

radar unit, the initial reading, was used as its reference distance. The difference between the reading and 

the initial reading was used to assess if the radar operated within accuracy specifications over a range of 

temperatures.

Distance to Water Testing

Three radar sensors were installed on a movable arm over still water in the HIF Hydraulic 

Laboratory. The vertical position of the arm was measured by a shaft encoder system. The water level 

was measured with a float and shaft encoder system. A DAA 500 XL Logger was used to sample and 

log the measurements made by the three radar sensors and the two encoders every 2.5 minutes. Two 

tests were conducted. Each test began with the arm located approximately 14 ft above the water. The 

arm was lowered, raised, and lowered in 3-ft increments from 14 to 5 ft above the water (fig. 3). The 

reference distance to the water surface was computed from the arm encoder reading and the water level 

encoder reading (fig. 4). The initial distance measurement made by a radar at approximately 14 ft above 

the water was used as its reference distance. The difference between the reference distance and the 

initial reference distance was used to compute the reference change in distance between the arm and the 

water surface—the reference difference. The difference between the reading and the initial reading was 

used to compute the change in distance between the radar and the water surface—the radar difference. 

The difference between the radar difference and the reference distance difference was used to assess 

whether the radar operated within accuracy specification over a range of air gaps.
4

SDI-12 Communication Testing

Three units were checked for compliance with SDI-12 version 1.3 using a NR Systems SDI-12 

verifier sold by NR Systems, Inc., with firmware version 1.6 and PC software version 5.1.0.4. The SDI12 verifier was connected to a PC and units were connected to the verifier and tested one at a time.

Field Testing

One unit, which was not used in the laboratory testing, was installed by the USGS Iowa Water 

Science Center at USGS streamgaging site 06808500, West Nishnabotna River at Randolph, Iowa. The 

drainage area for the site is 1,326 square miles. Instrumentation at the site included a bubbler water level 

system with a Sutron Accubar gage pressure sensor, and a DAA H3613 radar water level sensor. The 

data were collected from the instruments using standard USGS procedures. The data used for the field 

test were USGS provisional data collected from February 28 to July 11, 2013. The difference between 

the Sutron radar and the bubbler system and the difference between the Sutron radar and the DAA radar 

were used to compare the performance of the instruments. Periodic wire-weight gage readings were 

used to assess whether the Sutron radar, DAA radar, and bubbler system operated within accuracy 

requirements during the field test.

Results

Temperature Testing

The results from temperature testing in the walk-in chamber for the three units are shown in 

figures 5, 6, and 7. Only data that were collected when temperatures were changing less than 0.5 degree 

Celsius were plotted and checked for compliance to the accuracy specification. All units show minor 

effects from the temperatures, but do not have obvious trends. The average difference during the test 

was -0.017, -0.012, and -0.012 ft for the tested units. Summary statistics are listed in table 2 for the 898 

data points collected and checked for compliance with accuracy specification for each sensor. The 

average measurements for the sensors are within the accuracy specification, except for serial number 

1208558, which is marginally outside of the specification. Larger differences, which are outside of the 

manufacturer’s accuracy specification, occur at several temperatures. Except for serial number 1208558, 

the differences are all within 0.05 ft. Serial number 1208558 had three measurements with differences 

of nearly -0.15 ft. 

Table 2. Summary statistics for the difference between the Sutron RLR-0003-1 radar reading and the initial 

Sutron RLR-0003-1 radar reading at a stationary target for temperatures within 0.5 degree Celsius of -40, -20, 0, 

20, 40, and 60 degrees Celsius for serial numbers 1208558, 1208559, and 1208560. Number of data points 

analyzed for each sensor was 898.

Summary statistic 1208558 1208559 1208560

Feet

Minimum -0.15 -0.05 -0.05

Maximum 0.02 0.02 0.04

Average -0.017 -0.012 -0.012

Standard deviation 0.021 0.022 0.028
5

Distance to Water Testing

The results for the distance to water testing are shown in figures 8, 9, and 10. Two tests are 

shown plotted in a figure for each sensor along with the manufacturer’s accuracy specification. The 

accuracy specification is also shown and data points are plotted with vertical error bars that represent the 

uncertainty of the reference difference. Plotted data met the accuracy specification if either the data 

point was within the accuracy limits or the vertical error bar crossed inside the accuracy limits. Most 

measurements were within the manufacturer’s specified accuracy and the USGS accuracy requirements. 

Table 3 lists summary statistics for both tests, where the results were similar. Two of the three sensors 

tested were within manufacturer’s accuracy specification and the USGS accuracy requirement when the 

uncertainty of the reference measurement was included. Serial number 1208559 had a small but 

noticeable trend with increasing air gap that the other two sensors did not have. A small, vertical 

misalignment of the sensor or a slightly out-of-specification sensor are potential explanations for the 

cause of the trend. 

Table 3. Test 1 and test 2 summary statistics for the difference between the Sutron RLR-0003-1 radar difference 

with its initial reading and the reference difference with its initial reading. 

Summary statistic Test 1 Test 2

1208558 1208559 1208560 1208558 1208559 1208560

Minimum -0.02 -0.04 -0.02 -0.02 -0.03 -0.02

Maximum 0.01 0.00 0.00 0.00 0.00 0.00

Average -0.008 -0.024 0.012 -0.009 -0.016 -0.013

Standard deviation 0.004 0.011 0.009 0.005 0.010 0.008

 

SDI-12 Communication Testing

The three sensors tested passed the NR Systems SDI-12 verifier test. The verifier test results are 

not a complete comprehensive test of the standard but are indicative of the sensor meeting the timing 

and command requirements of the standard. 

Field Testing

The difference between the Sutron RLR-0003-1 and the bubbler system and the difference 

between the Sutron RLR-0003-1 and the DAA H3613 are plotted in figure 11. The differences shown in 

figure 11 are based on provisional data and are uncorrected. The differences are slightly larger with the 

bubbler system than for the DAA H3613 radar and range from approximately -0.20 to 0.10 ft. The 

average difference between the Sutron RLR-0003-1 and the bubbler system was 0.005 ft and the 

average difference between the Sutron RLR-0003-1 and the DAA H3613 was -0.002 ft. The Sutron 

RLR-0003-1 had good agreement with the bubbler and with the DAA H3613 water level readings for 

the data analyzed, from February 28 to July 11, 2013. Figure 12 is a plot comparing the differences 

between the Sutron RLR-0003-1 radar and the wire-weight gage readings, and the differences between 

the DAA H3613 and the wire-weight gage readings with the USGS OSW accuracy requirements. The 

vertical error bars represent an estimate of the accuracy of the wire-weight gage readings of 0.01 ft. The 
6

Sutron RLR-0003-1 differences look similar in shape to the DAA H3613 differences shown in figure 

11. The Sutron RLR-0003-1 meets the USGS accuracy requirements when compared to the wire-weight 

gage readings. 

Table 4. Summary statistics for the differences between the Sutron RLR-0003-1 and either the Accubar bubbler 

system or the Design Analysis Associates (DAA) H3613 for the period from February 28 to July 11, 2013. 

Summary statistic Bubbler system water level 

reading

Difference with bubbler

system Difference with DAA H3613

(feet) (feet) (feet)

Count 12,736 12,736 12,744

Minimum 7.61 -0.20 -0.15 

Maximum 14.29 0.10 0.06 

Average 9.52 -0.005 -0.002

Standard deviation 1.53 0.038 0.018

Summary 

The Sutron RLR-0003-1 was evaluated by subjecting units to laboratory, SDI-12 

communication, and field testing. Three Sutron RLR-0003-1 water level sensors were tested in 

laboratory conditions to evaluate the accuracy of the sensor over the manufacturer’s specified operating 

temperature and distance to water ranges. Laboratory results were compared to the manufacturer’s 

accuracy specification for water level and to the USGS Office of Surface Water (OSW) policy 

requirement that water level sensors have a measurement uncertainty of no more than 0.01 ft or 0.20 

percent of the indicated reading. Except for one sensor, the differences for the temperature testing were 

within 0.05 ft and the average measurements for the sensors were within the manufacturer’s accuracy 

specification. Two of the three sensors were within the manufacturer’s specified accuracy and met the 

USGS accuracy requirements for the laboratory distance to water testing. Three units passed a basic 

SDI-12 communication compliance test. The field test was conducted from February 28 to July 11, 

2013. Water level measurements made by using the Sutron RLR-0003-1 agreed well with those made by

using the bubbler system and a DAA H3613 radar during field testing at USGS streamgaging site 

06808500, West Nishnabotna River at Randolph, Iowa; the sensors also met the USGS accuracy 

requirements when compared to the wire-weight gage readings. 

Acknowledgments

The authors gratefully acknowledge Joe Nania, Joe Gorman, and the personnel of the USGS 

Iowa Water Science Center who conducted the field study and supplied the data used in the field testing

section of the report. 
7

References Cited

SDI-12 Support Group, 2013, SDI-12—A serial-digital interface standard for microprocessor-based 

sensors, version 1.3, 27 p., http://www.sdi-12.org/current%20specification/SDI12_version1_3%20January%2026,%202013.pdf.

Sutron Corporation, 2013, Radar level recorder RLR-0001-1 RLR-0003-1 operations and maintenance 

manual: Sutron Corporation, 67 p.

U.S. Geological Survey, 1996, Policy concerning accuracy of stage data: U.S. Geological Survey Office 

of Surface Water Technical Memorandum 96.05, unpaged, accessed September 5, 2013, at 

http://water.usgs.gov/admin/memo/SW/sw96.05.html.

For additional information regarding this publication, contact:

Chief, Hydrologic Instrumentation Facility

U.S. Geological Survey

Building 2101

Stennis Space Center, MS 39529

http://water.usgs.gov/hif/

Edited and prepared by:

USGS Science Publishing Network

Reston and Raleigh Publishing Service Centers
Figure 1. Photo of Sutron RLR-0003-1 water level sensor.

-60

-40

-20

0

20

40

60

80

0 8 16 24 32 40 48 56 64 72 80

Chamber Temperature in Degrees Celsius

Elapsed Time in Hours

Air Temperature

EXPLANATION

Figure 2. Temperatures applied during temperature testing for three Sutron RLR-0003-1 water level 

sensors. 
Figure 3. Definition sketch of hydraulic laboratory test measurement variables. Ai is the position of the arm 

supporting the radar unit under test, Ri is the radar measured air gap, and yi is the position of the water 

level during the test. The subscript i denotes the ith measurement.
0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0

2

4

6

8

10

12

14

16

0 25 50 75 100 125 150 175

WATER LEVEL IN FEET

REFERENCE AIR GAP IN FEET

ELAPSED TIME IN MINUTES

Reference

Air Gap

Water Level

Explanation

0

2

4

6

8

10

12

0

2

4

6

8

10

12

14

16

0 25 50 75 100 125 150 175

WATER LEVEL IN FEET

REFERENCE AIR GAP IN FEET

ELAPSED TIME IN MINUTES

Reference

Air Gap

Water Level

Explanation

Figure 4. Air gap applied and water level measured during air gap testing for three Sutron RLR-0003-1 

water level sensors. Top chart is for test 1 and bottom chart is for test 2.
-0.15

-0.1

-0.05

0

0.05

0.1

0.15

-45 -30 -15 0 15 30 45 60

Difference from Initial Reading in Feet

Temperature in Degrees Celsius

1208558

Accuracy Specification

EXPLANATION

Figure 5. Difference between initial measured distance to a stationary target made by Sutron RLR-0003-1 

(serial number 1208558) at room temperature and subsequent measurements made over temperatures 

from -40 to 60 degrees Celsius.

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

-45 -30 -15 0 15 30 45 60

Difference from Initial Reading in Feet

Temperature in Degrees Celsius

1208559

Accuracy Specification

EXPLANATION

Figure 6. Difference between initial measured distance to a stationary target made by Sutron RLR-0003-1 

(serial number 1208559) at room temperature and subsequent measurements made over temperatures 

from -40 to 60 degrees Celsius.
3-1

3-1

ater 

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

-45 -30 -15 0 15 30 45 60

Di

fference from Initial Reading in Feet 

Temperature in Degrees Celsius 

1208560

Accuracy Specification

EXPLANATION 

Figure 7. Difference between initial measured distance to a stationary target made by Sutron RLR-000

(serial number 1208560) at room temperature and subsequent measurements made over temperatures 

from -40 to 60 degrees Celsius.

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.00 5.00 10.00 15.00

DIFFERENCE BETWEEN RADAR and REFERENCE 

in FEET 

AIR GAP in FEET 

1208558 (1st

test)

1208558 (2nd

test)

Accuracy

Specification

Explanation 

Figure 8. Difference between the change in air gaps (distance to water) measured by Sutron RLR-000

(serial number 1208558) and measured by the references. The references were the arm position and w

level measured by a float system.
-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.00 5.00 10.00 15.00

DIFFERENCE BETWEEN RADAR and REFERENCE 

in FEET 

AIR GAP in FEET 

1208559 (1st

test)

1208559 (2nd

test)

Accuracy

Specification

Explanation 

Figure 9. Difference between the change in air gaps (distance to water) measured by Sutron RLR-0003-1

(serial number 1208559) and measured by the references. The references were the arm position and water 

level measured by a float system.

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.00 5.00 10.00 15.00

DIFFERENCE BETWEEN RADAR and REFERENCE in 

FEET 

AIR GAP in FEET 

1208560 (

test)

1208560 (

test)

Accuracy

Specificati

Explanation 

1st

2nd

on

Figure 10. Difference between the change in air gaps (distance to water) measured by Sutron RLR-0003-1

(serial number 1208560) and measured by the references. The references were the arm position and water 

level measured by a float system.
-0.3

-0.2

-0.1

0

0.1

0.2

0.3

7 8 9 10 11 12 13 14 15

Difference between Sutron RLR-0003-1 

and Bubbler Water Level Reading in 

Feet

Bubbler Water Level Reading in Feet

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

7 8 9 10 11 12 13 14 15

Difference between Sutron RLR-0003-1 

and DAA Radar Readings in Feet

DAA Radar Water Level Reading in Feet

Figure 11. Differences between the Sutron RLR-0003-1 and the Sutron Accubar bubbler water level 

system readings (top chart) and differences between the Sutron RLR-0003-1 and the Design Analysis 

Associates H3613 water level radar (bottom chart) at U.S. Geological Survey streamgaging site 06808500, 

for the period February 28, 2013 to July 11, 2013.
-0.05

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

6 8 10 12 14

Difference between Sensor and Reference Stage 

in Feet

Reference Stage in Feet

Sutron RLR-0003-1

DAA H3613

OSW accuracy

EXPLANATION

Figure 12. Comparison of the differences between the Sutron RLR-0003-1 radar, Design Analysis 

Associates (DAA) H3613 radar, and wire-weight gage readings plotted with U.S. Geological Survey Office 

of Surface Water (OSW) accuracy requirements.
ISSN 2331-1258 (online) 

 http://dx.doi.org/10.3133/ofr20141217