U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2013–1107

Prepared in cooperation with the Navajo Nation’s Department of Water Resources, Water 

Management Branch

Field Manual for the Collection of Navajo Nation 

Streamflow-Gage Data
COVER

Lukachukai Creek watershed on the Navajo Nation; photo by Jon Mason (USGS).
By Robert J. Hart and Gregory G. Fisk

Prepared in cooperation with the Navajo Nation’s Department of Water Resources, Water Management Branch

Open-File Report 2013–1107

U.S. Department of the Interior

U.S. Geological Survey

Field Manual for the Collection of Navajo Nation 

Streamflow-Gage Data
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

For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment:

World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS 

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 report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within 

this report.

Suggested citation:

Hart, R.J., and Fisk, G.G., 2014, Field manual for the collection of Navajo Nation streamflow-gage data: U.S. Geological Survey Open-File Report 2013–1107, 43 p., 

http://dx.doi.org/10.3133/ofr20131107.

ISSN 2231–1258
iii

Contents

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

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

Basics of a Streamflow Gage .............................................................................................................4

Determining the Purpose, Need, and Site Suitability of a Streamflow Gage ......................................5

Section I: Steps for Selecting Location of New Streamflow-Gaging Stations....................................6

Step 1. Determine Channel Characteristics and Requirements ...................................................6

Step 2. Establish Measuring Sections and Select Stage Sensors ...............................................8

Step 3. Determine Appropriate Reference Gages...........................................................................9

Section II: Field Visit Preparation..............................................................................................................11

Previsit Preparation............................................................................................................................11

Essential Field Equipment Checklist ................................................................................................13

Flow Meter Care and Maintenance.................................................................................................13

Section III: Steps for Routine Streamflow-Gage Visits .........................................................................16

Step 1. Make General Observations................................................................................................16

Step 2. Determine if Instruments are Operating Correctly ..........................................................16

Field Notes ...........................................................................................................................................19

Troubleshooting Instrumentation Problems ...................................................................................20

Section IV: Measurements of Peak-Flow Discharge Using Surveying Methods .............................21

Slope-Area Method............................................................................................................................23
iv Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Section V: Safety..........................................................................................................................................25

Job Hazard Analysis...........................................................................................................................25

Field Hazards .......................................................................................................................................25

Traffic Control .............................................................................................................................28

Section VI: Selected Streamflow-Gaging Terms ....................................................................................34

Section VII: Additional Resources by Category......................................................................................38

Instrumentation Resources...............................................................................................................38

Streamflow-Gage Operation.............................................................................................................38

Measurements of Streamflow..........................................................................................................39

Measurement of Peak Flow Discharge Using Surveying Methods ...........................................39

Acknowledgments.......................................................................................................................................40

References....................................................................................................................................................40

Figures

1. Map of Navajo Nation showing location of streamflow-gaging stations in Arizona 

and New Mexico.................................................................................................................................3

2. Diagram of typical stilling well gage and photo of Navajo Department 

of Water Resources gage located at Chinle Creek, Navajo Nation.....................................4
v

3. Examples of natural and artificial types of stage control................................................................7

4. Examples of instruments used to measure stage...........................................................................10

5. Examples of reference gages used to measure stream stage.....................................................12

6. Examples of instruments and methods used to measure flow.....................................................15

7. Examples of information needs for indirect measurements of discharge..................................22

Tables

1. Streamflow-gaging equipment and supplies...................................................................................14

2. Adjustment factors or component ranges for various channel conditions used 

to determine Manning’s n values.............................................................................................26

3. Example of a primary job hazard analysis checklist associated with 

servicing field sites.....................................................................................................................29

4. Example of a primary job hazard analysis checklist associated with 

environmental hazards ..............................................................................................................30

5. Example of a primary job hazard analysis checklist associated with 

cableway measurement............................................................................................................32

6. Example of a primary job hazard analysis checklist associated with 

wading measurements ..............................................................................................................33
vi Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

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)

mile (mi) 1.609 kilometer (km)

Area

Acre 0.4047 square hectometer (hm2

) 

Acre 0.004047 square kilometer (km2

)

square mile (mi2

) 259.0 hectare (ha)

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

acre-foot (acre-ft) 1,233 cubic meter (m3

)

gallon 3.785 Liter (L)

Flow rate

foot per second (ft/s) 0.3048 meter per second (m/s)

cubic foot per second (ft3

/s, cfs) 0.02832 cubic meter per second (m3/s, cms)

gallon per minute (gal/min, gpm) 0.06309 liter per second (L/s)

Mass

ounce, avoirdupois (oz) 28.35 gram (g)

pound, avoirdupois (lb) 0.4536 kilogram (kg)

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
Field Manual for the Collection of Navajo Nation StreamflowGage Data

By Robert J. Hart and Gregory G. Fisk

Abstract

The Field Manual for the Collection of Navajo Nation 

Streamflow-Gage Data (Navajo Field Manual) is based on 

established (standard) U.S. Geological Survey streamflowgaging methods and provides guidelines specifically designed 

for the Navajo Department of Water Resources personnel 

who establish and maintain streamflow gages. The Navajo 

Field Manual addresses field visits, including essential field 

equipment and the selection of and routine visits to streamflowgaging stations, examines surveying methods for determining 

peak flows (indirect measurements), discusses safety 

considerations, and defines basic terms. 

Introduction

The Navajo Department of Water Resources’ (NDWR) Water 

Management Branch is responsible for monitoring the streamflow 

of several Navajo Nation streams and washes. The Navajo Nation 

covers more than 27,000 square miles (mi2) in parts of Arizona, 

Utah, and New Mexico, and lies within three major river basins: 

the upper Colorado River Basin, the lower Colorado River Basin, 

and the Rio Grande Basin. Since the 1980s, the U.S. Geological Survey’s (USGS) Arizona Water Science Center (AZWSC) 

has assisted NDWR hydrographers, including hydrologists and 

hydrologic technicians, with all aspects of streamflow gaging. 

Most USGS streamflow-gaging stations measure stage and consist 
2 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

of a structure in which instruments used to measure, store, and 

transmit the stream-stage information are housed. Streamflow 

information has a wide variety of uses, including flood prediction, water management and allocation, municipal, industrial, and 

agricultural uses, and recreation. Presently, the Navajo Nation 

operates and maintains nine streamflow-gaging stations; all are 

located on the Navajo Reservation in eastern Arizona and western 

New Mexico (fig. 1). These gages and the primary method for 

stage monitoring (in parentheses) include:

1. Asaayi creek (pressure-transducer system)

2. Black Creek (float-driven stilling well)

3. Captain Tom Wash (float-driven stilling well)

4. Chinle Creek (float-driven stilling well)

5. Kinlichee Wash (float-driven stilling well)

6. Lukachukai Creek (float-driven stilling well)

7. Tsaile Creek (pressure-transducer system)

8. Wheatfields Creek (float-driven stilling well)

9. Whiskey Creek (float-driven stilling well)

Since the mid-1980s, the USGS AZWSC has been providing 

technical assistance and training to personnel of the NDWR 

Water Management Branch for field methods, gage installation 

and operation, surveying indirect measurements, and surfacewater record computation. 

The Field Manual for the Collection of Navajo Nation 

Streamflow Gage Data (Navajo Field Manual) is based on 

established (standard) USGS practices and provides guidelines 

specifically designed for NDWR personnel who establish and 

maintain streamflow-gaging stations. This step-by-step field 

manual is designed to assist new and experienced NDWR 

hydrographers in selecting sites and appropriate instrumentation 

to be used in streamflow gaging. This manual also includes a 

checklist of office tasks that are necessary for hydrographers 

to be efficient in the field. The manual is not intended to be an 

all-inclusive document on how to streamgage; such information 

already exists and is available from the USGS (see the Additional 

Resources section at the end of this guide). The USGS provides 

formal training to the NDWR concerning streamflow-gaging 

methods and streamflow-record computation. 

This training is part of Federal efforts to help tribal 

governments to manage their natural resources. 
3 Introduction

UTAH COLORADO

ARIZONA NEW

MEXICO

Canyon de Chelly

National Monument

Navajo

Nation

Page

Leupp

Aneth

Lupton

Ganado

Chinle

Tocito

Shonto

Jeddito

Cameron

Kaibito

Kayenta

Tohatchi

Moenkopi

Red Rock

Shiprock

Naschitti

Tuba City

Greasewood

Many Farms

Round Rock

Dennehotso

Window Rock

Mexican

Hat

Teec Nos Pos

Fort Defiance

Mexican Water

Mexican Springs

Montezuma Creek

Black

Creek

Tsaile Creek

Asaayi Creek

Chinle Creek

Whiskey Creek

Kinlichee Creek

Captain Tom Wash

Lukachukai Creek

Wheatfields Creek

111°30' 111°00’ 110°30' 110°00’ 109°30' 109°00’ 108°30'

37°00’

36°30’

36°00’

35°30’

0 10 20 MILES

0 2010 KILOMETERS

EXPLANATION

River, stream, 

creek, or wash

Road

Gaging site,

site name

Hopi Reservation

boundary

Base from U.S. Geological 

Survey National Elevation

Dataset 30-meter digital 

elevation model

UTAH

NEW

MEXICO

COLORADO

ARIZONA

191

264

87

77

491

163

160

191

98

160

89 264

Puerco

River

San Juan River

Chaco River

Chinlee Creek

Figure 1. Map 

of Navajo Nation 

showing location of 

area administered 

by the Navajo 

Department of Water 

Resources, Water 

Management Branch, 

and streamflow-gaging 

stations in Arizona and 

New Mexico. 
4 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Basics of a Streamflow Gage

The typical NWDR streamflow-gaging 

station is a float-driven stilling well (fig. 2). 

The use of stilling wells is one of the most 

common methods for measuring stream 

stage. The stilling well can be installed 

with intakes from the stream to the well 

(as shown in fig. 2A) and, therefore, the 

water level in the well is the same as the 

stream level. Stilling wells on the Navajo 

Reservation, however, are installed on the 

edge of streams and washes and, therefore, 

do not require the intakes (fig. 2B). The 

float is connected to a recorder in the gage 

shelter and responds to the changing water 

level in the stream. In the case of NDWR 

streamgages, the recorder is a strip chart or 

an electronic recorder. Pressure systems, 

contact (such as a pressure transducer) and 

noncontact (such as a WaterLog pressure 

system with an Accubar transducer), and 

radar systems provide other methods for 

sensing stream stage.

Figure 2. A, Diagram of a 

typical stilling-well gage and B, 

photo of Navajo Department of 

Water Resources gage located 

at Chinle Creek, Navajo Nation.

intakes

water surface

recorder

satellite

radio antenna

float

A B
5 Determining the Purpose, Need, and Site Suitability of a Streamflow Gage

Determining the Purpose, Need, and Site 

Suitability of a Streamflow Gage

Selecting the location of a new streamflow gage (or relocating 

an old gage) is dependent on the type of data that Navajo Nation 

managers need to meet their purposes. Streamflow data may be 

needed for a single purpose—such as early flood warning—or a 

variety of purposes depending on the general or specific needs for 

the Navajo Nation. Thus, streamflow gages may be installed to collect data that address the following purposes: 

• Measurement of surface-water supply

• Evaluation of surface-water quality for domestic and other uses

• Provision of baseline information to document current 

conditions

• Protection of water rights

• Provision of early flood warning 

In locating a new streamflow gage, hydrographers must be 

aware of the purpose of the gage and why the streamflow data are 

needed. For example, if a streamflow gage is used to evaluate the 

water quality of a spring, the gage must be located close to the 

source of the spring to minimize the effects of contamination that 

may be introduced between the spring source and the gage. If the 

purpose of a streamflow gage is to provide an early flood warning, then the gage should be located far enough upstream from the 

potentially affected towns or villages to give emergency managers 

as much time as possible to alert, and possibly evacuate, residents. 

Once the purpose of a gage has been determined, the site 

and channel characteristics will need to be thoroughly reviewed 

and evaluated for suitability. To evaluate the suitability of potential sites, hydrographers will have to make field visits to gather 

some critical information that includes:

•	 Access: Can the site be easily reached by vehicle? How will 

inclement weather affect access to the site during high-flow 

events?

•	 Land ownership or right-of-way: Because there is no 

private land ownership in most of the Navajo Nation, land 

ownership is often not a consideration. However, Navajo 

lands are mingled with private lands and Federal and State 

lands in the eastern part of the Navajo Nation in New Mexico. 

Right-of-way access or permissions also may be required by 

the Navajo Nation.

•	 Radio transmission (or satellite telemetry): This is important particularly if the streamflow gage is used for flood alert 
6 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

or warning. The NDWR typically uses radio communications 

and, therefore, it is important to locate the gage where the 

data can be transmitted to a base station. 

•	 Channel and streambed characteristics: Determine if 

the channel and streambed characteristics are conducive 

to providing good quality streamflow data. Characteristics 

to look for include—but are not limited to—the shape, 

low-flow control, steepness (slope) of the channel, and 

streambed material (sand, cobbles, boulders, or exposed 

bedrock).

•	 Instrumentation: What types of instruments are needed for 

the site? For example, a stilling well, pressure system, radar, 

or other.

•	 Measurement sections: Is a bridge available for high-water 

measurements, or will some other method for measuring 

high flows be needed such as a conventional stand-up or sitdown cableway or a cableway that is operated from the bank 

of the stream? A description of various types of cableways 

and installations can be found at the USGS Hydrologic 

Instrumentation Facility Web site at http://wwwrcamnl.

wr.usgs.gov/sws/SWTraining/cableways/descr.htm.

Section I: Steps for Selecting Location of 

New Streamflow-Gaging Stations

Step 1. Determine Channel Characteristics and 

Requirements

1. Determine the type of stage control (natural or artificial) that 

exists or will need to be installed at the site. See Section VI: 

Selected Streamflow-Gaging Terms, for a definition of stage 

controls. Figure 3 shows selected examples of stage controls, 

which include:

• Bedrock outcrop

• Boulder or gravel bar

• Weirs

• Concrete weir

• V-notch weir

• Broad-crested weir

• Low-water crossing

• Channel control

• Flumes

• Other (describe)
7 Section I: Steps for Selecting Location of New Streamflow-Gaging Stations

Figure 3. Examples of natural and artificial types of stage control. A, Bedrock outcrop, Wheatfields Creek, Navajo Nation; B, flume, 

Whiskey Creek, Navajo Nation; C, boulder and cobble, Asaayi Creek, Navajo Nation; D, Broad-crested weir at the Little Colorado River at 

Springerville, Arizona; E, channel control, downstream of gage at Moenkopi Wash, Arizona; and F, v-notch weir, Pasture Canyon Spring 

near Tuba City, Arizona. 

A B C D E F
8 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

2. Determine streambed and streambank characteristics. A stable 

streambed will yield a more accurate stage-discharge relation, but it can be challenging to find an ideal streambed in 

the Navajo Nation. Describe the streambed and streambank 

characteristics including: 

• Bedrock

• Gravel 

• Fine-grained sediments such as sand or silt

• Channel shape or the geometry of the channel

• Streambed characteristics (that is, stable or highly erodible) 

• Control type (for example, gravel bar, bedrock outcrop, 

channel, or other control type—note that controls change 

with the stage and discharge of the stream)

• Slope of the channel (Does the channel reach have a small 

or large change in elevation?)

• Channel roughness (Does the channel contain large or 

small rocks, trees or brush? Is the reach straight?)

• Streambed that is subject to scour (for example, finer 

grained sediments are subject to greater movement than 

coarser grained sediments such as rock and cobble)

• Streambanks that are subject to sloughing

• Streambanks that have gradual slopes

• Streambanks that have steep slopes

• Streambanks that are heavily vegetated

• Streambanks that are void of vegetation

• Other conditions (describe)

Step 2. Establish Measuring Sections and Select 

Stage Sensors

1. Determine measuring sections for low to high flows. When 

establishing sections, remember measurements should be made 

in close proximity to the gage and streamflow should be even 

in the cross section (velocities fairly equal where streamflow 

is parallel to the banks). For more information on this topic, 

references are provided in Section VII: Additional Resources by 

Category. Additionally, hydrographers should select (1) a wading section for low to medium stage and (2) a bridge or cableway measurement location for high flows. If measurements of 

high flow are not possible, the hydrographer should describe 

the reach where surveying methods could be used to determine 

peak flows (this topic is discussed in Section IV: Measuring 

Peak Flows Using Surveying Methods—Indirect Method).
9 Section I: Steps for Selecting Location of New Streamflow-Gaging Stations

2. Select the appropriate stage sensor and reference gages for 

reading stage for the site. Stream characteristics and availability of manmade structures such as bridges will govern what 

type of stage sensor is appropriate. Also, determine if 

telemetry will be used. Select from the following types of 

stage sensors (see fig. 4):

• Float drive encoders are suitable for low-sedimentconcentration, nonalluvial and nonmeandering streambeds 

because they will provide more accurate stage data than 

streambeds without these characteristics. This type of sensor requires a vertical wall or bridge to attach the stilling 

well. If the well is subject to freezing, a heat tape or oil tube 

system may be required. Strip chart recorders or data loggers are used with encoders to read the stage of the stream.

• Submersible pressure transducers are the least expensive of the sensors available, and they are easy to install. 

Submersible pressure transducers can stand alone or be 

connected to a data logger. In meandering streams, the 

sensor can be relocated or multiple sensors can be installed 

to cover changing stream conditions. This type of sensor is 

subject to instrument failure from ice and sediment.

• Nonsubmersible pressure transducers require an 

orifice line. If ice is present or sediment covers the orifice 

intakes, then this type of sensor is prone to recording erroneous data. Like the submersible pressure transducers, 

in meandering streams the orifice line can be relocated or 

multiple orifice lines can be installed to cover changing 

stream conditions.

• Noncontact radar sensors are suspended over the water, 

usually from a bridge, and are unaffected by sediment accumulation or transport in alluvial channels. This type of 

sensor can easily be moved over the channel (if mounted 

to a bridge crossing) when the stream meanders.

Step 3. Determine Appropriate Reference Gages

1. Determine the reference gage(s) to be used at the site. Reference gages are used to verify that the data loggers and stage 

sensors are sensing data correctly. There are various types of 

reference gages and purposes for using them. In most cases, 

the USGS uses all three types of reference gages listed below 

at gage sites. For a complete description of these gages, refer 

to Section VI: Selected Streamflow-Gaging Terms and Section VII: Additional Resources by Category. Figure 5 shows 

examples of various types of reference gages.
10 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Noncontact 

radar gage

Car key 

(for scale)

Orifice line for a 

pressure system

A-71 Strip chart

A B

C

D

E F G

Figure 4.

Examples of 

instruments used 

to measure stage. 

A, Incremental 

encoder connected 

to a float tape 

that is in contact 

with the water 

surface; B, shelter 

at Wheatfields 

gage with an 

A-71 strip chart, 

stage encoder, 

and a radio data 

transmitter; C, 

noncontact radar 

system mounted 

to cottonwood tree at Paria River, Lees Ferry, 

Arizona; D, pressure sensor used to measure water 

pressure (or level); E, float system in stilling well 

and a staff gage, Lukachukai Creek, Navajo Nation; 

F, gas-purge orifice line (exposed in dry wash); and 

G, gas-purge system.
11 Section II: Field Visit Preparation

•	 Staff gages and reference points (RPs) must be located 

as close to the stage sensor as possible and in the same 

gage pool. Staff gages can be read directly to determine 

the stage of the stream whereas RPs require the hydrographer to tape down to the water surface. The tape-down 

reading can then be referenced to the predetermined elevation of the RP. 

•	 Crest-stage gages (CSGs) are used to record peak flows 

for comparison to the primary gage, and they must be in 

the same gage pool and in an area protected from debris 

during high flows. The hydrographer should inspect these 

gages during each routine field trip to assure the CSG is in 

proper working order. 

•	 Wire-weight gage is a type of reference gage consisting of a wire-wrapped drum and weight; the weight is 

lowered to the water surface by turning the drum with 

the attached handle to measure the elevation. That 

water-surface elevation reading is then compared to the 

primary gage; elevations from the wire-weight gage and 

the primary gage should agree within ± 0.01 feet. These 

gages require a bridge railing or some other similar type 

of structure for installation. 

Section II: Field Visit Preparation 

Previsit Preparation

Field visit preparation is critical to ensuring staff safety 

and making efficient use of time during field visits. A common 

mistake is putting off field trip preparation until the last minute. 

Before selecting a streamflow-gage site or making other field trip 

preparations, the following activities should be completed:

• Understand the purpose for which the data will be collected.

• Review the work plan and know the types of measurements 

and samples needed.

• Make a field reconnaissance trip before selecting streamflowgaging locations, noting conditions that could affect 

streamflow gaging activities.

• Review site files and field folders, noting location, description, 

access, and previously collected data for each site to be visited.

• Obtain and keep current with the training requirements 

associated with the hydrographer’s data-collection activities 

(adapted from Wilde and others, 1998).
12 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Figure 5. Examples of reference gages used to measure stream stage. A, Wire-weight gage mounted to the bridge at Springerville, 

Arizona; B, crest-stage gage with measuring stick removed (arrow points to high-water mark on the concrete abutment); C, inside and 

outside staff plates, Kinlichee Creek, Navajo Nation; D, pressure sensor of a continuous-slope area gage, Williamson Valley, Arizona; E, 

continuous slope-area gage—pressure sensor (shown in fig. 5D) is housed in steel pipe—Williamson Valley, Arizona; and F, reference 

point (RP; nail in root) used to tape down to the water surface.

RP: nail in root

Note high-water 

mark on bridge 

abutment

Dry streambed; direction of flow

A B C D E F
13 Section II: Field Visit Preparation

Essential Field Equipment Checklist

This section of the Navajo Field Manual provides a checklist 

of essential field equipment. A more comprehensive list is 

provided in table 1. Field vehicles should be equipped for routine 

and emergency gage-repair trips and ready to depart on flood 

trips in an efficient manner. The hydrographer is responsible for 

ensuring that proper field equipment is available and in good 

working order. Because most streamflow-gaging stations are 

located in remote areas, it is advisable to pack food, water, and 

extra clothing. 

Flow Meter Care and Maintenance 

The care and calibration of flow meters, or current-velocity 

meters, is the most critical element of previsit preparation. Flow 

meters that will function accurately in the flow conditions of the 

stream (for example Price Pygmy or AA meters) should be taken 

on each site visit; it also is recommended that hydrographers take 

a spare flow meter with them into the field in the event of equipment failure. Although requirements differ for mechanical and 

acoustic flow meters, the following general care and maintenance 

activities are recommended: 

• Maintain meter-calibration log books to track the performance 

of meters; logs can help detect decreased efficiency resulting 

from poor (damaged) meter pivots or low batteries. 

• Replace batteries for acoustic meters and the AquaCalc on a 

routine basis.

• Confirm electrical continuity for mechanical flow meters (Price 

AA and Price Pygmy current meters) before each field trip.

• Perform spin tests before and after each field trip and after 

meter repairs. Also, if streams are laden with sediment or 

debris, it is suggested to perform a spin test before and after 

the discharge measurement is made. This should be done in a 

controlled environment such as the cab of a vehicle to eliminate any effects from wind. The minimum spin time is 2 minutes for a Price AA meter and 45 seconds for a Price Pygmy 

meter. Results of the spin test should be noted on the front 

sheet of the field notes as “ok” or “free” to indicate a visual 

check was acceptable (Turnipseed and Sauer, 2010). 

• Check and test suspension reels (Type A or B-56 sounding 

reels) twice a year to ensure electrical connections are good 

between the reel and the meter. Examples of instruments used 

to measure flow are shown in figure 6.
14 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

✔ Qty. Item

❑ 1 Cloth tape, 50 feet

❑ 1 Tagline, 300 feet

❑ 1 Steel measuring tape

❑ Discharge note forms, field-station descriptions, and road logs

❑ 1 AquaCalc (in-stream discharge measurement computer) 

and two spare 9-volt batteries

❑ 2 Price AA current meter (1 is recommended for backup if 

using a FlowTracker®)

❑ 2 Price Pygmy current meter (1 is recommend for backup if 

using a FlowTracker®)

❑ 2 Wading rod 

❑ 2 Headset with batteries

❑ 1 Pigtail connector (used to connect to headset or AquaCalc 

to the measuring reel)

❑ 1 FlowTracker® velocimeter

❑ 1 Spare float and float tape for float-drive encoder stage sensors

❑ 1 Volt-amp meter

❑ 1 Engineer’s folding ruler

❑ Plastic sample bottles

❑ 1 Digital camera

❑ 2 Spare batteries

❑ 1 Laptop computer or pocket PC such as an HP IPAC with 

appropriate software to download data from data loggers

❑ 2 Celsius thermometers that have been checked against a 

certified laboratory thermometer

❑ Paper copies of the rating curve and table

[Note: the hydrographers will include other types of equipment or supplies that they feel are necessary and preferential that may not be listed here]

✔ Qty. Item

❑ Navajo Department of Water Resources Flood Plan, if 

available

❑ 1 pr Chest waders

❑ 1 pr Hip boots

❑ 1 Rain gear

❑ 2 Personal floatation device

❑ 1 Skin protection such as sunscreen

Special equipment for high-flow or flood measurements 

❑ Bridge and cable measuring equipment

❑ 1 Bridge board and 4-wheel base bridge boom

❑ 4 Counter weights for the 4-wheel base crane, 50 pounds

❑ 1 ea 30-, 50-, 75-, 100-pound sounding weights (150-pound 

sounding weight, if available); for use with the Price AA 

current meter during high flows from bridges or cableways.

❑ 2 Sounding-weight pins and hanger rods

❑ 1 B-56 sounding reel with quick-release mechanism

❑ 1 Type A sounding reel

❑ 1 Hand level

❑ 1 Roll of flagging tape for marking HWMs

❑ 1 Cable car puller

Miscellaneous equipment and supplies

❑ Tool kit

❑ Flashlight with extra batteries

❑ Cellular or satellite phone 

❑ First aid kit

Table 1. Streamflow-gaging equipment and supplies. 
15 Section II: Field Visit Preparation

Figure 6. Examples of instruments and methods used to measure flow. A, Three types of flow meters (FlowTracker®, Price Pygmy, and Price 

AA); B, FlowTracker® in use at Kinlichee Wash, Navajo Nation; C, Parshall flume, Captain Tom Wash, Navajo Nation; D, Pygmy meter in use at 

Kinlichee Wash, Navajo Nation; E, Price AA meter attached to 30-pound sounding weight, Moenkopi Wash, Arizona; F, measuring high flow 

using a bridge board at Moenkopi Wash, Arizona; G, measuring high flow using a bridge boom at Oak Creek, Sedona, Arizona; and H, measuring 

high flow from a cableway at Verde River, Paulden, Arizona.

B

H

C

F

D

A G

FlowTracker® Price Pygmy meter

Price AA meter

E
16 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Section III: Steps for Routine Streamflow 

Gage Visits

If streamflow gages are equipped with telemetryorradio

communications, data can be scanned remotely fromtheoffice,

field, or home (if Internet service is available) toidentifypossible instrument problems and to determine current conditions 

of streamflow. 

Step 1. Make General Observations

1. Upon arrival, set out safety equipment. Prepare and assemble 

necessary equipment. Park vehicle in a location and direction 

so as not to block the roadway. 

2. In the field notes (see below), record the current stage of the

stream from the following gages:

• Reference gages (reference points, staff plates, or wireweight gage)

• Data logger 

• Float-drive encoder

3. Make general observations of the site in the field notes.

4. Take photos of the stage control and the gage reach. Document 

any changes you report in the field notes, and be sure to record 

the photo number along with a description.

5. Inspect the gaging station, the shelter, and the instruments. 

Write appropriate observations in the field notes.

6. Inspect the crest-stage gage (CSG) and peak-stage indicator

(PSI) for high-water marks (HWMs). The PSI is a simple clip 

that attaches to the steel tape and marks the highest stage on the 

tape. Inspect other sources where HWMs may be documented, 

including in stilling wells or along the streambanks. If HWMs 

are found along the streambanks, use flagging and large nails to 

mark the HWM line upstream and downstream of the gage or, 

if already selected, in the slope-area reach of the gage. 

Step 2. Determine if Instruments are Operating 

Correctly

1. Determine if the stage sensor (the primary gage) is operating 

correctly. Good notes are required regarding the condition 

and the results of testing the sensors for proper operation. 
17 Section III: Steps for Routine Streamflow Gage Visits

Any changes in stage that result from testing the sensors need 

to be documented in the field notes. If errors are found after 

the tests are completed, reset the data logger to reflect the 

corrected stage. Use the following methods for verifying the 

operation of each specific sensor:

• Check float-driven encoders by rotating the steel tape wheel 

and observe if the stage changes on the encoder (fig. 4A).

• Purge nonsubmersible transducers by increasing the gas 

pressure in the orifice line for about 1 minute. Ream the 

orifice line where it is exposed to the stream to ensure 

that it is not plugged with debris. Following the purge, 

test the transducer’s operation by temporarily plugging 

the orifice line where it is exposed at the stream. A 

change in stage (an increase) should be observed with 

the data logger and, after the plug is removed, the stage 

should return to the previous reading.

• While observing changes on the data logger, raise and 

lower submersible transducers in the stream to ensure they 

are operational.

2. Check noncontact sensors such as radar sensing equipment 

on all gage inspections. If there is not a significant change in 

stage during inspections, test the sensor manually by holding 

a piece of poster board under the sensor while it is scanning 

data and verify that the stage is changing.

3. Check the battery voltage and record results in the field notes. 

If the voltage is less than 12 volts, replace the battery. Also, 

if available, check the amperage with an amp meter. The amp 

meter will measure the strength of an electric current and, 

therefore, provide the hydrographer with information about 

the strength of the battery.

4. Determine what the stage control is at the current stage and 

where the control is in relation to the gage. Document in 

the field notes and take photographs of the condition of the 

control. For example, note whether or not there is debris on 

the control, if aquatic growth in the channel is present, or 

if scour in the streambed has occurred since the last visit. 

[Note: All these factors affect the control reach by raising or 

lowering the stage of the control reach—which in turn affects 

the stage-discharge rating for the site. Rating shifts are often 

applied to discharge measurements when these conditions 

occur to account for more or less water at the site.]

5. During several visits to the site, determine the point of zero 

flow (PZF) by measuring the low point of the stage control. 

The PZF is the lowest point of the control where flow ceases. 
18 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

This information is particularly important for streams that 

go dry periodically. 

6. Make the discharge measurement in the vicinity of the 

gage at the best possible cross section for a given stage. 

Check the flow meter for performance by conducting a 

spin test (as discussed earlier in the “Flow Meter Care 

and Maintenance” section of this guide) before and after 

each field trip (Turnipseed and Sauer, 2010). Discharge 

measurement notes, a preprinted type of field notes (USGS 

form 9-275-F), provide a place for documenting the spin 

test. 

7. Estimate the discharge if a rating curve and table are 

not yet developed for the site in order to determine 

what method and flow meter to use. The discharge can 

be estimated by determining the width (in feet) of the 

measuring section and estimating an average depth (in 

feet) and velocity (in feet per second); width x depth x 

velocity=discharge in cubic feet per second (ft3/s). An 

average velocity can be estimated by floating a stick or 

other buoyant item between a measured distance, noting 

the travel time, and multiplying that time by distance and 

by 0.8.

8. Determine the discharge from the rating table if the site 

has a developed rating curve (this should be available 

in the hydrographer’s field folder) using the existing 

stage reading. The discharge from the rating will help 

the hydrographer determine what method and flow meter 

to use for measuring the flow. If the flow is extremely 

low, a volumetric method may be the only choice. For 

discharge values between 0.1 and 0.4 ft3

/s, use a Parshall 

flume (see “Section VII: Selected Streamflow-Gaging 

Terms”). For discharge greater than 0.4 ft3/s, use a 

Price AA or Price Pygmy current meter or a SonTek 

FlowTracker®.

9. Ensure that the measurement documents all discharge 

that passes the gage; there should be no secondary 

streamflow that is not accounted for by the gage. An 

example of secondary flow would be a secondary stream 

channel that may divert flow around the gage (upstream 

of the gage) and therefore not be accounted for.

10. The ideal channel cross section for a measurement would 

be a firm sand-gravel or bedrock bottom with even 

(equal) depths and velocity. This condition is rare in 

many Navajo Nation streams and washes. 
19 Section III: Steps for Routine Streamflow Gage Visits

11. Use 25 to 30 vertical subsections within the measuring 

section (with a goal of no more than 5 percent of the flow 

in any section) in a typical measurement cross section.

12. Compute the discharge after completing the measurement 

on site (see “Section VII: Additional Resources by 

Category—Measurements of Streamflow;” Rantz, S.E., 

and others, 1982). Plot the discharge on the rating curve 

(a rating curve and table for the gage should be kept on 

site in the gage house as well as in your field folder). If 

the measurement plots more than 5 percent away from 

the rating curve, and there has not been a significant 

change to the control, a check measurement is required. 

The check measurement is made with a different meter 

and in a different cross section of the reach. 

13. After the discharge measurement has been completed, 

read all gages (primary and reference gages) again, 

determine an average gage height for the measurement, 

and record in the field notes.

14. Check the data logger and transmitter for proper 

operation before leaving the gage site. Be sure the shelter 

is locked and secured.

Field Notes

Good field notes provide the basis for producing quality streamflow 

records and correctly analyzing the data. For these reasons, a protocol 

should be established for data-collection activities; measurement and 

inspection notes should be complete and made at the gage site. One way 

to capture all relevant information is to use USGS Discharge Measurement Notes, which are printed on waterproof paper and can be ordered 

online at http://www.rickly.com/sga/usgsforms.htm. These preprinted 

forms are formatted to USGS requirements (Form 9-275-F), and the front 

cover includes specific fields for recording the following information: 

1.	 Condition of the site: indicate if the site has been vandalized or 

damaged by high water.

2.	 Condition of instrumentation: indicate if the instruments have 

been damaged or vandalized or are not working for other reasons.

3.	 Changes in the gage reach: indicate if changes have occurred 

because of high water or streambank eroding or calving. 

4.	 Condition of the stage control: indicate whether the stage 

control has been modified or damaged in any way. For example, 

has the natural stage control been scoured by high flows? Has 

the artificial control, such as a V-notch weir, been damaged or 

clogged with debris?
20 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

The front cover of the field notes also provides space to 

record detailed information related to the discharge measurement 

and stage of the stream. The rest of the form is used for noting 

measurement information for each subsection measurement in the 

cross section. 

Troubleshooting Instrumentation Problems

Troubleshooting data loggers and stage sensors can be 

difficult because of the complexity of their electronics. In many 

cases, instrument components can be replaced, which will 

often solve the problem. However, the most common cause of 

instrument failure is loss of power to the instrument. This type 

of problem is easy to diagnose and repair by (1) checking all 

electrical connections to be sure they are secure and (2) using a 

voltmeter to check the voltage of the instruments to be sure the 

power available is adequate. If the voltage is low, it can be due 

to excess power consumption in the instrument; the instrument 

should be repaired or replaced, if this is the case. If the gagehouse equipment is powered through a solar panel, that may be 

the source of the problem—solar panels eventually wear out 

and need to be replaced. Another common cause for electrical 

problems or failure is the regulator—if it fails, the battery will 

not be charged. The following is a list of common problems 

related to specific instruments:

• Float-driven encoder systems seldom fail, but when they do 

fail, the most probable cause is related to loss of power to the 

encoder, damage to a sinking float, or the steel tape disengaging 

from the float-wheel spline during high-flow events.

• Nonsubmersible transducer systems are subject to pressure 

leaks in the orifice line and ice or debris buildup over the 

orifice intake. These problems can be diagnosed by simply 

observing the stage record, which will reflect erroneous 

stage data. If a pressure leak is occurring, the stage record 

will reflect a lower-than-normal stage because of the loss of 

pressure. If ice or debris has accumulated on the orifice line, 

the stage will reflect a higher-than-normal stage because of 

the increase in pressure. Pressure leaks are difficult to locate, 

but in many cases, leaks can be detected by applying soapy 

water around connections or suspected areas of damage to 

the orifice line. The leaking gas will create bubbles in the 

soapy water.

• Submersible transducer systems simply fail over time and cannot 

be repaired, so replacement of the transducers is the only option.
21 Section IV: Measurements of Peak-Flow Discharge Using Surveying Methods 

• Noncontact sensors such as radar units can only be checked 

when there is water in the gage pool or by reflecting the radar 

wave off a piece of poster board. If the sensor does not agree 

with the reference gage, this lack of agreement may be a 

sign that the sensor is failing. The sensor should be checked, 

verified, and if necessary, replaced.

Section IV: Measurements of Peak-Flow 

Discharge Using Surveying Methods 

The measurement of peak-flow discharge is an important 

element in collecting a good hydrologic record of streamflow. 

Because of the flashy nature of high flows on Navajo Nation 

streams and washes, and also the inability to access a gage in 

a timely manner, it is difficult to obtain a measurement of peak 

flows using standard measurement methods. When the hydrographer cannot make a measurement, surveying methods can be 

used to determine the discharge following the high-flow event. 

These methods are referred to as “indirect methods” of determining peak-flow discharge. Indirect measurement methods require a 

team of hydrographers to survey cross sections of the channel in 

the vicinity of the gaging station and determine channel geometry 

and slope from a series of high-water marks. The surveyed cross 

section provides information about the depth of the channel and 

the geometry of the stream. Using a series of at least three cross 

sections, the slope of the surveyed reach can be calculated. The 

geometry of the reach and the slope can then be used to compute 

the discharge. Examples of information needs for making indirect 

measurements of discharge are shown in figure 7. 

There are several methods of making indirect measurements, 

including the following: 

• Contracted bridge openings

• Flow-through culverts

• Slope-area computation

• Flow-over weirs

• Step-backwater model analysis

Step-backwater models, such as HEC-RAS (a U.S.Army 

Corps of Engineers model, available at http://www.hec.usace.

army.mil/software/hec-ras/hec-georas_downloads.html), are 

normally used for initial rating-curve development but can also be 

used to determine peak flows. However, they require more crosssection surveys. Because most of the Navajo Nation’s streams and 

washes are natural, open channels, the slope-area method will be 

used in most cases. The following section describes the steps and 

data needed for the slope-area method of computing discharge. 
22 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Figure 7. Examples of information needs for indirect measurements of discharge. A, Cross section at Black Creek, 

Navajo Nation; B, surveying crew (Joel Unema, U.S. Geological Survey, Bel B. Pachai and Linda Lee, Navajo 

Department of Water Resources) at Kinlichee Creek, Navajo Nation; C, high-water mark along Paria River, Lees Ferry, 

Arizona; D, wash line along Paria River, Lees Ferry, Arizona; E, example of channel roughness with sand channel and 

vegetation along active channel, Black Creek, Navajo Nation; F, example of channel roughness with vegetation and 

large cobbles along the active channel, Captain Tom Wash, Navajo Nation; and G, example of channel roughness with 

vegetation along active channel, Chinle Wash, Navajo Nation. 

A B

G

C D E F

High-water mark Wash line
23 Section IV: Measurements of Peak-Flow Discharge Using Surveying Methods 

Slope-Area Method

The slope-area method of determining discharge is based on 

surveying cross sections (typically three), calculating the watersurface slope from cross-section geometry, and assigning roughness values (see discussion below, in the section called “Channel 

Roughness”) that describe the channel-reach geometry and highwater marks (HWMs) on both sides of the banks. Data collected 

from the survey are entered into a USGS slope-area computer 

program (SAC; see “Section VIII: Additional Resources by 

Category,” Fulford, 1994). The SAC follows USGS standardized 

procedures for computing discharge by the slope-area method. 

The program solves the 1-D steady-state energy and continuity 

equations for discharge given upstream and downstream watersurface elevations. As with computing discharge directly with 

current-velocity meters, the collection of accurate field data is 

critical. A level, or total station transit, is needed for surveying 

the channel reach and collecting other elevation data that are 

required. The following is a list of important tasks and observations that need to be made to employ the slope-area method:

• High-water marks (HWMs) are an important piece of 

information needed for the slope-area method; they are used 

to define the depth and slope of the water surface between 

the cross sections for a particular flow event. HWMs are the 

accumulation of debris—seeds, grass, small limbs or twigs, 

or wash lines—along the streambanks and indicate the highest stage (elevation) of the high-water event. These marks can 

also be found along canyon walls and around tree trunks. Be 

aware that some HWMs may provide an erroneous reading; 

typically these types of HWMs can be found in tree limbs or 

other vegetation that is not rigid enough to withstand the high 

velocities that can occur during high flows. HWMs will quickly 

degrade or erode as time passes, so it is extremely important to 

visit the site as soon as possible following a flood or high-flow 

event. Tying flagging to long nails provides an easy method for 

marking HWMs. Both banks are flagged with 15 to 20 marks, 

depending on the length of the reach, and these HWMs are 

surveyed along both banks in the entire reach if possible.

• Channel-reach geometry should be relatively straight and 

of equal width or slightly contracting as it goes downstream. 

Ideally the channel reach should be in the vicinity of the 

gage. The discharge calculation will be more accurate if the 

banks and channel are stable and free of brush and debris. The 

discharge estimate is also more accurate if the flow is confined 

to one channel with no overbank flow. In most cases, alluvial 

sand channels are poor indirect channel reaches because the 
24 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

stream bed is unstable and the channel geometry during the 

peak flow may be significantly different than indicated from 

the postflow cross section surveys. In general, the length of 

the reach should be equal to or greater than 75 times the mean 

depth in the channel (Dalrymple and Benson, 1984).

• Channel cross sections are selected based on the channel geometry and a minimum of 3 are recommended for slope-area 

calculations. Criteria for selecting cross sections are described 

by Benson and Dalrymple (1967).

• Surveying the HWMs and cross sections requires the use of 

a level or a total station transit. The survey levels are first run 

to the HWMs on both banks. Streamwise distance 

(x coordinate), cross-stream distance (y coordinate), and 

elevation (z coordinate) are measured at all the HWMs. A highwater surface profile is then drawn using a computer program 

(see “Section VII: Additional Resources by Category;” Fulford, 

1994) or can be hand-drawn using the surveyed data and used 

to determine the location of the channel cross sections. Crosssections typically have 15–20 points that define the breaks in 

slope and the general geometry of the cross sections. 

• Channel roughness is an estimate that needs to be made 

while in the field. Roughness parameters (Manning’s n) are 

coefficients that have been developed for various channel 

conditions that affect the depth and velocity of flow. Channel 

conditions including irregularity of the channel, cross section 

variation, channel obstructions or material, vegetative growth 

on the channel banks and in the channel, and the meanders 

of the stream affect the flow (velocity and volume) of water 

during a flow event. These channel conditions are used to 

adjust the roughness coefficient (Manning’s n) and can range 

from 0.030 for sand channels clear of vegetation to greater 

than 0.065 for heavily vegetated channels with boulder 

streambeds. Streams with higher roughness coefficients 

will convey less water. Table 2 can be used to determine the 

roughness coefficient for indirect measurement of peak flow 

discharge by summing the Manning’s n adjustment for each 

channel condition. For more in-depth information on this 

topic, see Section VII: Additional Resources by Category; 

Aldridge and Garrett (1973); and Phillips and Tadayon (2006). 

• Notes and photographs should be taken using transit-level 

field notes that are available commercially or through the 

USGS. As with a site visit to a gage, accurate level notes 

are necessary to compute discharge from indirect methods. 

Photographs should be taken to document HWMs, cross 

section reaches, and roughness characteristics. 
25 Section V: Safety

• Final computation of discharge using the data 

collected for the slope-area method can be done by 

hand or with the USGS slope-area computer program 

(Fulford, 1994). Using either method, Microsoft Office 

Excel spreadsheet works extremely well for transposing 

field notes of cross-section data; the data can be worked 

by hand or easily imported into the USGS SAC program 

to produce discharge and other pertinent information.

Section V: Safety

Job Hazard Analysis

Safety is the number one priority for all hydrographers in the 

field, especially in remote areas. A Job Hazard Analysis (JHA) 

includes a list of hazards associated with each gage site and should 

be written for every site. JHAs should include environmental 

hazards as well as work-related hazards. Examples of hazards to be 

included in JHAs are as follows and are shown in tables 3–6: 

• Fast and deep water

• Temperature—heat and cold

• Poisonous snakes and insects

• Rough terrain

• Quicksand—this is a real and dangerous hazard in sand-bedded streams

• Other environmental hazards

• Inadequate swimming ability of the hydrographer

The USGS provides detailed instruction as to what is required 

in a JHA (available online at http://www.usgs.gov/usgs-manual/

handbook/hb/445-2-h/ch15.html) and OSHA (Occupational Safety 

and Heath Administration) provides an online booklet at http://

www.osha.gov/Publications/osha3071.pdf. 

Field Hazards

Perhaps the most important precautionary practice the 

hydrographer can do to avoid field hazards is to prepare a trip 

itinerary and leave a copy with the supervisor or other designated 

persons. The itinerary should include phone numbers where the 

hydrographer can be reached, trip route, and lodging or camping 

information. In most cases, cell phone coverage is available on the 

Navajo Nation and, therefore, a cell phone should be carried at all 

times. Enter the telephone numbers of nearby hospitals and other 

emergency facilities in your cell phone, and have a written list in 

your vehicle and/or on your person that includes their location. 
26 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Table 2. Adjustment factors or component ranges for various channel conditions used to determine Manning’s n values.

[From Phillips and Tadayon, 2006]

Channel 

conditions

Manning’s n

adjustment Example 

Degree of irregularity

Smooth 0.000 Smoothest channel attainable in a given bed material

Minor 0.001–0.005 Channels with slightly scoured or eroded side slopes

Moderate 0.006–0.010 Channels with moderately sloughed or eroded side slopes

Severe 0.011–0.020 Channels with badly sloughed banks; unshaped, jagged, and irregular surfaces of channels in rock

Variation in channel cross section

Gradual 0.000 Size and shape of channel cross sections change gradually

Alternating 

occasionally

0.001–0.005 Large and small cross sections alternate occasionally, or the main flow occasionally shifts from side to side owing to 

changes in cross section shape

Alternating 

frequently

0.010–0.015 Large and small cross sections alternate frequently, or the main flow frequently shifts from side to side owing to 

changes in cross section shape

Effect of obstructions

Negligible 0.000–0.004 A few scattered obstructions, which include debris deposits, stumps, exposed roots, logs, piers, or isolated boulders, 

which occupy less than 5 percent of the channel

Minor 0.005–0.015 Obstructions occupy from 5 to 15 percent of the cross-sectional area and spacing between obstructions is such that 

the sphere of influence around one obstruction does not extend to the sphere of influence around another obstruction. 

Smaller adjustments are used for curved, smooth-surfaced objects than are used for sharp-edged, angular objects

Appreciable 0.020–0.030 Obstructions occupy from 15 to 50 percent of the cross-sectional area, or the space between obstructions is small 

enough to cause the effects of severe obstructions to be additive, thereby blocking an equivalent part of a cross section

Severe 0.040–0.060 Obstructions occupy more than 50 percent of the cross-sectional area, or the space between obstructions is small 

enough to cause turbulence across most of the cross section
27 Section V: Safety

Table 2. Adjustment factors or component ranges for various channel conditions used to determine Manning’s n values.—Continued

Channel 

conditions

Manning’s n

adjustment Example 

Amount of vegetation

Negligible 0.000–0.002 Grass, shrubs, or weeds were permanently laid over during flow

Small 0.002–0.010 Dense growths of flexible turf grass, such as Bermuda, or weeds growing where the average depth of flow is at least 

two times the height of the vegetation where the vegetation is not laid over. Trees, such as willow, cottonwood, or 

saltcedar, growing where the average depth of flow is at least three times the height of the vegetation. Flow depth is 

about two times the tree height, and the trees are laid over

Medium 0.010–0.025 Moderately dense grass, weeds, or tree seedlings growing where the average depth of flow is from two to three times 

the height of vegetation; brushy, moderately dense vegetation, similar to 1- to 2-year-old willow trees growing along 

the banks. A few 8- to 10-year old willow, cottonwood, mesquite, or palo verde, which block flow by approximately 

1 to 10 percent, and spheres of influence or turbulence do not overlap 

Large 0.025–0.050 8- to 10-year-old willow, cottonwood, mesquite or palo verde trees (block flow by approximately 10 to 30 percent where 

the spheres of influence overlap) intergrown with some weeds and brush where the hydraulic radius exceeds 2 feet.

Very large 0.050–0.100 Bushy willow trees about 1 year old intergrown with weeds alongside slopes or dense cattails growing along the 

channel bottom; trees intergrown with weeds and brush. Moderately dense 8- to 10-year old trees spaced randomly 

throughout channel (blocks flow by approximately 30 to 50 percent and the spheres of influence overlap) where depth 

of flow approximates height of vegetation

Extremely 

large

0.100–0.200 Mature (greater than 10 years old) willow trees and tamarisk intergrown with brush and blocking flow by more than 

70 percent of the flow area, causing turbulence across most of the section. Depth of flow is less than average height of 

the vegetation. Dense stands of palo verde or mesquite that block flow by 70 percent or more and hydraulic radius is 

about equal to or greater than average height of vegetation.

Degree of meandering

Minor 1.00 Ratio of the channel length to valley length is 1.0 to 1.2

Appreciable 1.15 Ratio of the channel length to valley length is 1.2 to 1.5

Severe 1.30 Ratio of the channel length to valley length is greater than 1.5 
28 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

To prevent field hazards associated with stream gaging, 

the hydrographer needs to be aware of stream conditions 

at each site. Streams or washes should not be waded if the 

product of the depth of the stream (in feet) times the velocity 

(in feet per second) equals 10 or more. For example, if a 

stream is 4.5 feet deep and the velocity is 3.0 feet per second, 

then it would be considered unsafe as the product equals 13.5. 

Application of this rule varies among individuals, according to 

their weight and stature, and to the condition of the streambed. 

Personal floatation devices (PFDs) should be worn during 

stream conditions that may pose a drowning hazard.

During construction projects such as routine maintenance, 

installation of new gages, or installation of cableways, the 

hydrographer should wear appropriate protective clothing such 

as steel-toed boots and a hard hat. Long-sleeved shirts and pants 

will provide protection from sun exposure and help prevent skin 

contact with vegetation.

Preventative maintenance at streamflow gages will reduce 

field hazards. For example, cableways should be inspected on 

an annual basis by a qualified and trained hydrographer. The 

USGS can provide this service and appropriate training to 

the NDWR. Other preventative maintenance such as access 

trails or roads to the gage will reduce hazards associated with 

travel. 

Unfortunately field hazards will occur at times so the 

hydrographer should carry an appropriate first-aid kit. Cuts, 

insect bites, and other potential injuries such as these will 

happen, and the hydrographer needs to be prepared to address 

them adequately when in the field. Some hazards that may 

seem to be minor can develop into a more serious situation 

and so seeking medical attention for certain injuries is a 

priority. 

Traffic Control

Currently, the NDWR does not maintain any streamflow 

gages near roadsides where traffic control is needed. However, 

if such sites are added to the gaging network, a traffic and 

bridge safety plan should be developed. The USGS and the 

Arizona Department of Transportation can provide assistance with 

developing this plan.
29 Section V: Safety

Table 3. Example of a primary job hazard analysis checklist associated with servicing field sites.

Sequence of basic job steps Potential accidents/

hazards Recommended safe job procedures

Loading equipment Pinching fingers, 

mashing toes, back 

strain

Use caution, be aware of hand placement, use proper lifting techniques (for 

example, lift with legs not back, get assistance as necessary). Wear gloves, steeltoed shoes, and back support.

Driving to the job site Traffic accident Stay alert to driving conditions and obey all traffic laws. Reduce speed for 

hazardous conditions.

Parking the vehicle Vehicle safety Park as far from roadway as possible. Use hazard warning lights and light bar.

Determining type of task to be done Traffic & personal safety Stay alert to traffic and surroundings. Wear reflective vest or PFD as necessary.

Setting up traffic control equipment Traffic & personal safety Be alert to traffic conditions.

Removing traffic control equipment Traffic & personal safety Be alert to traffic conditions.

Driving to the office Traffic accident Stay alert to driving conditions and obey all traffic laws. Reduce speed for 

hazardous conditions.

Unloading equipment Pinching fingers, 

mashing toes, back 

strain

Use caution, be aware of hand placement, use proper lifting techniques (for 

example, lift with legs not back, get assistance as necessary). Wear gloves, steeltoed shoes, and back support.

Recommended protective clothing and equipment

PFD, traffic control equipment, reflective vest, hard hat, safety glasses, gloves, steel-toed shoes, and back support

[PFD, personal flotation device]
30 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Sequence of 

basic job steps

Potential accidents/hazards Recommended safe job procedures

Walking to, 

from, and 

around field 

site

Trips and falls Ensure path is clear and free of obstructions. Ensure that footing at the field site work area is 

sound.

Lightning strikes Do not work around or during thunder storms.

Dehydration, heat exhaustion, 

or sun stroke

In warm or hot weather, rest often and drink plenty of water or electrolyte drink.

Hypothermia or frostbite Wear foul-weather gear during winter months.

Sunburn Protect yourself from sun. Use sunblock, wear light-protective clothing, sunglasses, and hat.

Bruise, sprain, sting Use caution and walk appropriately for the circumstances.

Slippery conditions Use appropriate foot wear when mud, snow, or ice conditions exists.

Snake bites Wear appropriate foot and leg protection. If you are bitten seek medical help immediately. DO 

NOT "cut and suck." This may make the bite worse.

Attack by wild animals Be familiar with animal behavior. 

Insect bites or stings Wear appropriate insect repellant. At the end of work day check your body carefully for ticks. 

Avoid wasps or hornets nests.

Poisonous plants Wear appropriate clothing. Wash all exposed areas of skin with cold water only.

Table 4. Example of a primary job hazard analysis checklist associated with environmental hazards. 

[PFD, personal flotation device]
31 Section V: Safety

Sequence of 

basic job steps

Potential accidents/hazards Recommended safe job procedures

Opening gage 

house or other 

type shelter

Insect bites or stings Check carefully around shelter for wasps or spiders. Use sprays (wasp stopper) to kill insects.

Snake bites Check carefully around and inside shelter for snakes.

Infectious diseases Watch for bats, rodent nests, or droppings. If a nest or droppings are present, special 

precautions must be taken to prevent illness or death. See cleaning protocol.

Working in or 

around surface 

waters

Infectious water-borne diseases Wear appropriate gloves. Prevent water from contacting your skin.

Contaminated water source Wear appropriate gloves. Prevent water from contacting your skin. Work in well-ventilated 

area.

Snake bites Wear appropriate foot and leg protection. If you are bitten, seek medical help immediately. 

DO NOT "cut and suck." This may make the bite worse.

Drowning / rapidly rising stage Wear PFD. Be familiar with weather conditions occurring upstream. Be prepared to move to 

higher ground.

Recommended protective clothing and equipment

Safety glasses, gloves, footwear, PFD, electrolyte drink, sunblock, sunglasses, protective clothing, foul-weather gear, insect repellent, rope, and shovel

Table 4. Example of a primary job hazard analysis checklist associated with environmental hazards.—Continued
32 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Sequence of basic job steps Potential accidents/hazards Recommended safe job procedures

Unloading equipment from vehicle 

and moving equipment to cablecar

Pinching fingers, mashing toes, 

back strain

Use caution, be aware of hand placement, use proper lifting techniques 

(lift with legs not back, get assistance as necessary). Wear gloves, 

steel-toed shoes, and back support.

Making measurement Structure failure, fall from tower 

or cable car, floating or submerged 

debris

Wear PFD. Do not climb ladders while carrying other equipment. Be 

alert to debris, have cutters ready if sounding cable needs to be cut.

Moving equipment from cablecar 

to vehicle and reloading equipment

Pinching fingers, mashing toes, 

back strain

Use caution, be aware of hand placement, use proper lifting techniques 

(lift with legs not back, get assistance as necessary). Wear gloves, 

steel-toed shoes, and back support.

Recommended protective clothing and equipment:

Gloves, steel-toed shoes, back support, PFD, cable cutters

Table 5. Example of a primary job hazard analysis checklist associated with cableway measurement. 

[PFD, personal flotation device]
33 Section V: Safety

Table 6. Example of a primary job hazard analysis checklist associated with wading measurements. 

Sequence of 

basic job steps

Potential accidents/

hazards Recommended safe job procedures

Entering 

stream

Submerged debris Proceed slowly, testing the bottom with your wading rod. Urban streams near bridges could have a wide 

variety of junk discarded over the bridge.

Floating debris Be aware of surroundings; watch upstream for drift.

Soft stream bottom Use the wading rod to test bottom before stepping.

Stringing 

tagline

Slippery concrete or rock 

bottom due to algae

Wear steel "creepers" on boots or waders for traction. Wear waders with nonslip soles. Do not enter 

concrete flood channels except during low flow and fair weather.

High velocity or depth Check field folder for safe limits. Know your own limits. If velocities become too high, do not try to 

turn around midstream, back out.

Boat traffic Use flags on tagline. Have cutters ready. Have a second person on shore to warn boating traffic. Use 

alternate ways to measure distance such as a handheld laser range finder. Wear highly visible clothing.

Making 

measurement

Hypothermia Wear flotation gear that also helps keep you warm such as a float coat. Wear foul weather gear. Keep 

waders and hip boots in good condition. Have extra set of clothes.

Sun and heat exposure Use sunscreen, wear hat, drink liquids. Learn to recognize heat exhaustion, heat stroke, and dehydration.

Lightning Do not enter stream if there is lightning is in the area.

Rapidly rising stage Check weather forecast. Know how your site responds to local rain storms or how it responds to rain 

upstream in the drainage. Do not enter water during significant rainfall. Exit stream before conditions 

become unsafe. If necessary, throw tagline in stream and retrieve at lower stage.

Removing 

tagline

Tagline getting snagged Carefully wade out to snag and free or cut tagline. If stage or velocity increase dangerously, abandon tag 

line and recover it at a lower stage.

Exiting stream Slippery surfaces, steep 

banks, undercut banks, 

debris piles

Wear PFD and felt or other nonslip soles. Use wading rod for support. Cut temporary steps into bank. 

Use rope tied to tree or other support for help. Grab tree limbs or branches cautiously, they may have 

thorns or be poison oak, for example.
34 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Section VI: Selected Streamflow-Gaging 

Terms

This section provides an explanation of some of the more 

common hydrologic terms. The USGS maintains various online 

water resource glossaries (http://water.usgs.gov/glossaries.

html) that provide detailed explanations of an extensive range of 

hydrologic terms. 

Base flow is the flow of a stream that does not reflect direct 

surface-water runoff. Base flow is usually groundwater discharge 

from the local aquifer, but it can also be artificially induced by 

effluent discharge (return flows) from water-treatment facilities. 

Channel roughness is a measure of the resistance to flow created 

by the channel material. The roughness of a channel is typically 

represented by a roughness parameter, such as Manning’s n (see 

Phillips and Tadayon, 2006; and Aldridge and Garrett, 1973). 

Continuous slope-area (CSA) method, which expands on the 

slope-area method of computing high flow, was developed by 

the USGS to estimate a complete flow-event hydrograph. Both 

methods allow the hydrographer to produce more complete 

discharge records than would otherwise be possible because 

of resource limitations or logistical obstacles. Continuously 

recording pressure transducers are installed and their 

measurements of water-surface slopes and stages are used to 

generate continuous hydrographs and rating curves (Smith and 

others, 2010). 

Crest-stage gage (CSG) is a device for obtaining the highest 

stage (peak stage) that occurs during a flow event. It is a simple 

measuring device that consists of a steel pipe (of varying 

lengths), a wooden ruler that fits inside the pipe, a slotted end cap 

that allows water to enter the pipe, and a fine-grained cork, which 

floats and adheres to the wooden ruler at the level of the highest 

stage. CSGs also can be instrumented with a pressure transducer 

as a means for recording the entire flow event in conjunction 

with the ruler and cork method. A series of CSGs can also be 

installed and instrumented with a continuous recording pressure 

transducer (see CSA, above) in a reach upstream or downstream 

of the gage for use in indirect measurements. CSGs are useful 

for documenting the peak stage for comparison with the primary 

gage record. 

Discharge, or flow, is the amount of water that passes by the 

gaging station per unit of time, which is typically expressed in 

cubic feet per second (ft3

/s or cfs) or gallons per minute (gal/

min or gpm). Discharge is computed, not measured. Using the 
35 Section VI: Selected Streamflow-Gaging Terms

velocity and the area (depth multiplied by width) measured at 

about 25 locations along the measuring section, the hydrographer 

computes the total discharge for the stream at the time of the 

measurement. The total discharge is referred to as streamflow. 

Flow meters are instruments used to measure the speed of the 

water, or velocity, expressed in feet per second. Flow meters 

are either mechanical or acoustic. Mechanical meters include 

several types, but the most common are the Price AA current 

meter and the Price Pygmy current meter. A mechanical meter 

has a wheel of six metal cups that revolve around a vertical 

axis, much like a windmill. The revolutions are counted and 

timed by the hydrographer using a headset and stopwatch to 

determine the speed of the water. Acoustic flow meters (such as 

the FlowTracker Handheld-AVD® (acoustic Doppler velocimeter) 

made by SonTek) sense the speed of the stream from the acoustic 

Doppler effect of suspended particles moving in the stream. 

The transmitter of the flow meter sends multiple sound signals 

through the water that bounce off suspended particles in the 

water. The reflected sound signals that return to the receiver of 

the flow meter have a modified frequency that is related to the 

velocity of the suspended particles. 

Flumes are artificial channels used to make discharge 

measurements; they consist of a converging section, a throat 

section, and a diverging section. The constricted throat produces 

a head that is related to the discharge. The flow rate through the 

flume is a function of the liquid level at head of the flume. A 

Parshall flume is one of the most commonly used flumes (Rantz 

and others, 1982, v. 2). 

Gage datum “is a horizontal surface used as a zero point for 

measurement of stage or gage height. This surface usually is 

located slightly below the lowest point of the stream bottom such 

that the gage height is usually slightly greater than the maximum 

depth of water. Because the gage datum is not an actual physical 

object, the datum is usually defined by specifying the elevations of 

permanent reference marks such as bridge abutments and survey 

monuments (brass tablets), and the gage is set to agree with the 

reference marks. Gage datum is a local datum that is maintained 

independently of any national geodetic datum. However, if the 

elevation of the gage datum relative to the national datum (National 

Geodetic Vertical Datum of 1929 or North American Vertical 

Datum of 1988) has been determined, then the gage readings can 

be converted to elevations above the national datum by adding the 

elevation of the gage datum to the gage reading (Kenney, 2010).” 

Gage pool, or reach, is the part of the stream channel that is 

created by the stage control and represents the conditions of the 

stream for physical, chemical, and biological characteristics. It is 
36 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

the gage pool that is being monitored for changes by gage sensors 

such as a stilling-well float.

High-water marks (HWMs) are natural indicators of the highest 

level reached by a body of water. A debris line, seed line, or wash 

line forms along the banks of the stream resulting from high water. 

HWMs are usually visible along streambanks, trunks of large trees, 

and boulders, as well as inside stilling wells. The crest-stage gage 

is used to document HWMs. The HWM is the highest level or 

stage of the flow event and can be used to verify the gage record or 

used in determining discharge using indirect methods.

Orifice line is part of a gas-purge system that transmits the 

pressure head of water in the stream to the pressure transducer 

location. The pressure in the gas line of the gas-purge system is 

equal to the pressure head of the stream. When the stream stage 

changes (increasing or decreasing head pressure), the gas-purge 

system responds accordingly. 

Peak-stage indicator (PSI) is a clip that attaches to the steel tape 

of a float-driven encoder and moves along the tape as the stage 

rises. The PSI is set under the shelf where the steel tape passes 

through from the float to the encoder. The PSI will mark the 

highest peak stage that occurred between site visits.

Reference gage, staff plate, or staff gage is a graduated ruler 

used to reference to the primary gage. It is read during each routine field trip to the gage to verify that the recording gage (the primary gage record) is sensing or measuring the stage (gage height) 

correctly by observing the water level on the staff plate. Staff plates 

should be mounted vertically on the inside (if using a stilling well) 

and outside of the gage structure or near the gaging station. 

Reference point (RP) is a permanent marker such as a lag bolt 

inserted into a rock or some other solid feature. The RP is located 

near the gaging station where the hydrographer can tape down 

from it to the water surface to measure the stage of the stream 

gage pool with a graduated measuring tape or ruler. Like the 

reference gage, the RP is another way to verify that the recording 

gage is reading and recording accurately. The RP is also used to 

maintain datum integrity for the gage.

Strip chart recorders predate electronic data loggers and use a 

roll or strip of paper that is passed beneath one or more ink pens 

to record data. The strip chart recorder does not sense the stage 

but records the response of the stage from a float-driven stage 

sensor. Strip chart recorders, including the Stevens A-71, are used 

at some Navajo Nation gaging stations.

Stage, or gage height, is simply the water-surface elevation above 

or below a vertical reference point, which is often close to the 

streambed, used as a zero point for measurements. Stage is typically 

measured in feet and to the nearest 0.01 ft. An experienced hydrog-
37 Section VI: Selected Streamflow-Gaging Terms

rapher can use stage to determine low-, medium-, or high-water 

conditions. After a stage-discharge rating curve (see definition in this 

section of the report) is developed for a site, the hydrographer can 

use the stage to determine the discharge before going in the field. See 

figure 4 for examples of instruments used to measure stage.

Stage controls are physical features in the stream channel that 

affect or control the stage. The stage control determines the 

stage-discharge relation at the gage. There are various types of 

stage controls, including (1) a constriction of the channel, (2) a 

bedrock outcrop, (3) a gravel bar, and (4) an artificial structure 

(such as a V-notch weir or low-water road crossing), which is 

usually effective for low stages. A uniform cross-section control 

over a long reach of the channel is effective for medium to high 

stages. The control is sensitive to changes that may occur in the 

gaged reach. These changes can be caused by aquatic growth, 

accumulation of debris or sediment, and scour of vegetation, 

sediment, or bed material. The following are typical controls for 

low stages that exist at Navajo streamflow gages (fig. 3): 

1.	 Constriction control is caused by the narrowing of the 

channel that controls the stage of the gage pool. This type of 

control is effective for medium and high stages, but also low 

stage depending on the site. An example of this exists at Black 

Creek, Navajo Nation. 

2.	 Bedrock control is an outcrop of rock that is exposed in the 

stream channel and is effective for low stage in the gage pool. 

An example of this stage control exists at the Wheatfields 

Creek, Navajo Nation. 

3.	 Gravel bar control, or cobble control, is a feature of the channel where coarse bed material (such as gravel) exists, which is 

effective during low stage of the gage pool. An example of this 

stage control exists at the Asaayi Creek, Navajo Nation. 

4.	 Artificial control is a manmade feature and can include a Vnotch weir (typically constructed of steel) or a low-water road 

crossing (constructed of concrete). These features are excellent 

stage controls, particularly at low stages, but a low-water crossing 

may also be effective for medium to higher stages. An example of 

this stage control exists at Whiskey Creek, Navajo Nation. 

These low-stage controls are normally submerged at 

medium to higher stages when the channel’s roughness and 

geometry below the gage pool becomes the control and is 

referred to as a channel control. Compound controls exist at 

most Navajo streamflow-gaging sites because of the channel 

characteristics. Compound controls consist of the types of 

low-stage controls described above and the channel control for 

medium to high stages. 
38 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Stage-discharge relation, or rating curve, is the relation between the gage height, usually plotted as ordinate, and the amount 

of water flowing in a channel, expressed as volume per unit of 

time, plotted as abscissa (http://water.usgs.gov/wsc/glossary.

html#Stagedischargecurve). The stage-discharge relation is developed by making numerous measurements of discharge at different stages. The discharge is referenced to the stage at the time the 

discharge measurement was made. A rating curve is then developed 

from this relationship that covers the range in stage for the gage site. 

The stage-discharge relation at a gage is unique to each gage site. 

Stage sensors are instruments that measure the level of the 

stream on a continuous basis and are referred to as the primary 

gage. There are many types of stage sensors including (1) floatdrive encoders, (2) gas-purge systems, (3) pressure transducers, 

and (4) noncontact sensors such as radar systems. These instruments respond to the changing stage at the gage. On the Navajo 

Nation, the typical sensors used are the stilling-well floats or 

pressure transducers (see fig. 4).

Volumetric method is a method of discharge measurement that 

is only applicable to small discharges, but it is the most accurate 

method of measuring such flows. The method requires measuring 

the time required to fill a container of a known capacity, or the 

time required to partly fill a calibrated container to a known volume. The only equipment required is a stopwatch and container. 

Section VII: Additional Resources by 

Category

Instrumentation Resources

U.S. Geological Survey Hydrologic Instrumentation Facility, 

http://water.usgs.gov/hif

Streamflow Gage Operation 

Olsen, S.A., and Norris, J.M., 2007, U.S. Geological Survey 

streamgaging...from the National Streamflow Information 

Program: U.S. Geological Survey Fact Sheet 2005–3131, 4 p., 

http://pubs.usgs.gov/fs/2005/3131/FS2005-3131.pdf.

Sauer, V.B., and Turnipseed, D.P., 2010, Stage measurement at 

gaging stations: U.S. Geological Survey Techniques and Methods, book 3, chap. A7, 45 p., http://pubs.usgs.gov/tm/tm3-a7/.

Kenney, T.A., 2010, Levels at gaging stations: U.S. Geological 

Survey Techniques and Methods, book 3, chap. A19, 60 p., 

http://pubs.usgs.gov/tm/tm3A19/.
39 Section VII: Additional Resources by Category

Measurements of Streamflow

Nolan, K.M., Frey, C., and Jacobson, J., 1998, Surface-water field 

techniques training class (online training class, last updated 

May 2, 2008): U.S. Geological Survey Water-Resources 

Investigations Report 98–4252, available at http://wwwrcamnl.

wr.usgs.gov/sws/SWTraining/FlashFandR/Index.html.

Nolan, K.M., and Shields, R.R., Measurement of stream discharge by wading (online training class, last updated Dec. 16, 

2010): U.S. Geological Survey Water-Resources Investigations 

Report 00–4036, version 1.1, available at http://training.usgs.

gov/ntc/courses/cbt-cdrom/wrir00-4036.html.

Rantz, S.E., and others, 1982, Measurement of stage and discharge, vol. 1 in Rantz, S.E., and others, Measurement and 

computation of streamflow: U.S. Geological Survey Water 

Supply Paper 2175, 284 p. 

Rantz, S.E., and others, 1982, Computation of discharge, vol. 2 in

Rantz, S.E., and others, Measurement and computation of streamflow: U.S. Geological Survey Water Supply Paper 2175, 346 p.

Turnipseed, D.P., and Sauer, V.B., 2010, Discharge measurements at gaging stations: U.S. Geological Survey Techniques 

and Methods, book 3, chap. A8, 87 p., http://pubs.usgs.gov/tm/

tm3-a8/.

Measurement of Peak Flow Discharge Using 

Surveying Methods 

Aldridge, B.N., and Garrett, J.M., 1973, Roughness coefficients 

for stream channels in Arizona: U.S. Geological Survey OpenFile Report 73–3, 87 p., http://pubs.er.usgs.gov/publication/

ofr733.

Arcement, G.J., Jr., and Schneider, V.R., 1989, Guide for selecting Manning’s roughness coefficients for natural channels 

and flood plains: U.S. Geological Survey Water-Supply Paper 

2339, 44 p.

Dalrmyple, T., and Benson, M.A., 1984, Measurement of peak discharge by the slope-area method: U.S. Geological Survey Techniques of Water-Resources Investigations, chap. A2, book 3, 12 p.

Fulford, J.M., 1994, User’s guide to SAC, a computer program 

for computing discharge by the slope-area method: U.S. Geological Survey Open-File Report 94-360, 31 p.

Hortness, J.E., 2004, SAM 2.1—A computer program for plotting 

and formatting surveying data for estimating peak discharges 

by the slope-area method: U.S. Geological Survey Fact Sheet 

2004–3028, 4 p., http://pubs.usgs.gov/fs/2004/3028/.
40 Field Manual for the Collection of Navajo Nation Streamflow-Gage Data

Acknowledgments

The Navajo Field Manual was prepared, reviewed, and field 

tested by professional hydrographers at the Navajo Department 

of Water Resources (NDWR) and the U.S. Geological Survey 

(USGS). The authors would like to give special thanks to NDWR 

Hydrologist Bel B. Pachhai and NDWR hydrologic technicians 

Irving Brady and Jerome Bekis for their support and assistance 

in preparing this field manual. The authors also wish to recognize 

the many USGS Arizona Water Science Center hydrologists and 

hydrologic technicians who provided field training and conducted 

surface-water record computations for the NDWR. Also, thanks 

to Jon Mason, USGS, for many photos used in this guide.

References 

Aldridge, B.N., and Garrett, J.M., 1973, Roughness coefficients 

for stream channels in Arizona: U.S. Geological Survey OpenFile Report 73-3, 87 p., http://pubs.er.usgs.gov/publication/

ofr733.

Arcement, G.J., Jr. and Schneider, V.R., 1989, Guide for selecting 

Manning’s roughness coefficients for natural channels and flood 

plains: U.S. Geological Survey Water-Supply Paper 2339, 44 p.

Benson, M.A., and Dalrymple, T., 1967, General field and 

office procedures for indirect discharge measurements: 

U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 3, chap. A1, 35 p.

Dalrymple, T., and Benson, M.A., 1984, Measurement of peak 

discharge by the slope-area method: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 3, chap. 

A2, 12 p.

Fulford, J.M., 1994, User’s guide to SAC, a computer program 

for computing discharge by the slope-area method: U.S. 

Geological Survey Open-File Report 94–360, 31 p.

Hortness, J.E., 2004, SAM 2.1—A computer program for plotting 

and formatting surveying data for estimating peak discharges 

by the slope-area method: U.S. Geological Survey Fact Sheet 

2004–3028, 4 p., http://pubs.usgs.gov/fs/2004/3028/.

Kenney, T.A., 2010, Levels at gaging stations: U.S. Geological 

Survey Techniques and Methods, book 3, chap. A19, 60 p.

Nolan, K.M., Frey, C., and Jacobson, J., 1998, Surface-water field 

techniques training class (online training class, last updated 

May 2, 2008): U.S. Geological Survey Water-Resources Investigations Report 98–4252, at http://wwwrcamnl.wr.usgs.gov/

sws/SWTraining/FlashFandR/Index.html.
41 References

Nolan, K.M., and Shields, R.R., Measurement of stream discharge by wading (online training class, last updated Dec. 16, 

2010): U.S. Geological Survey Water-Resources Investigations Report 00–4036, version 1.1, http://training.usgs.gov/

ntc/courses/cbt-cdrom/wrir00-4036.html.

Olsen, S.A., and Norris, J.M., 2007, U.S. Geological Survey 

streamgaging...from the National Streamflow Information 

Program: U.S. Geological Survey Fact Sheet 2005–3131, 4 

p., http://pubs.usgs.gov/fs/2005/3131/FS2005-3131.pdf.

Phillips, J.V., and Tadayon, S., 2006, Selection of Manning’s 

roughness coefficient for natural and constructed vegetated 

and nonvegetated channels, and vegetation maintenance plan 

guidelines for vegetated channels in central Arizona: U.S. 

Geological Survey Scientific Investigations Report 2006–

5108, 41 p., http://pubs.usgs.gov/sir/2006/5108/. 

Rantz, S.E., and others, 1982, Measurement of stage and 

discharge, vol. 1 in Rantz, S.E., and others, Measurement and 

computation of streamflow: U.S. Geological Survey Water 

Supply Paper 2175, 284 p. 

Rantz, S.E., and others, 1982, Computation of discharge, vol. 2 

in Rantz, S.E., and others, Measurement and computation of 

streamflow: U.S. Geological Survey Water Supply Paper 2175, 

346 p.

Sauer, V.B., and Turnipseed, D.P., 2010, Stage measurement at gaging 

stations: U.S. Geological Survey Techniques and Methods, book 3, 

chap. A7, 45 p., http://pubs.usgs.gov/tm/tm3-a7/.

Smith, C.F., Cordova, J.T., and Wiele, S.M., 2010, The continuous 

slope-area method for computing event hydrographs: U.S. 

Geological Survey Scientific Investigations Report 2010–5241, 

37 p.

Turnipseed, D.P., and Sauer, V.B., 2010, Discharge measurements at 

gaging stations: U.S. Geological Survey Techniques and Methods, 

book 3, chap. A8, 87 p., http://pubs.usgs.gov/tm/tm3-a8/.

Wilde, F.D., Radke, D.B., Gibs, J., and Iwatsubo, R.T., 1998, 

National field manual for the collection of water-quality 

data: U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 9, chap. A1–A9. 
This page left intentionally blank.
Menlo Park Publishing Service Center, California

Manuscript approved for publication February 20, 2013 

Edited by Larry B. Slack and Claire M. Landowski

Design and layout by Jeanne S. DiLeo
Open-File Report 2013–1107 — Field Manual for the Collection of Navajo Nation Streamflow-Gage Data — Hart and Fisk

ISSN 2231–1258 (online)

Ihttp://dx.doi.org/10.3133/ofr20131107