Why monitor river levels?

The U.S.Army Corps of Engineers 

uses river levels to monitor rivers and 

regulate dams to control flooding. The 

National Weather Service uses river 

levels to issue flood warnings. State and 

local agencies rely on USGS river levels 

to monitor water uses such as those for 

water supplies and sewage-treatment 

plants, to develop regulations regarding 

water uses, and to ensure that river 

levels do not decline below certain 

levels as a result of use. Environmentalists, fishermen, boaters, and 

white-water rafters make use of river 

levels for the status of the rivers. 

Real-Time Reporting

Transmitting data to other locations 

by satellite radio or by telephone, 

almost instantaneously in times of 

emergency, is one of the most valuable 

features of a USGS streamflow station. 

Figure 2 illustrates how the signal containing data at a USGS streamflow station equipped with a radio is sent from 

the station to a satellite, to a ground 

receiving station, and, finally, to a 

USGS computer that processes the data. 

Alternatively, the data are transmitted 

directly to the USGS computer or the 

station is called by telephone. Figure 3 

shows the telemetry attached to a USGS 

streamflow station. Of the streamflow 

stations currently (1997) being operated 

in Massachusetts and Rhode Island, 36 

are equipped with instruments that 

transmit river levels by radio or telephone, usually every 4 hours (“realtime” data). River levels converted to 

streamflow data from 25 stat

Massachusetts and Rhode Is

then posted automatically on 

World Wide Web (web) site. 

shows how river levels at the 

River, in Waltham, Massach

reported every 4 hours in “re

satellite radio changed in res

the flood of October 1996.

In times of floods and droughts, immediate access to river level data is important to officials charge

responsibilities of protecting lives and property by taking actions to diminish the adverse effects of 

emergency. The U.S. Geological Survey (USGS), in cooperation with many Federal, State, and loc

agencies, is the Nation’s principal collector of accurate and unbiased streamflow data, and thus is t

emergency officials rely on to provide the needed river data. The USGS operates and maintains mo

7,000 continuous-record streamflow-gaging stations on rivers in the United States; 84 of these stati

Massachusetts and Rhode Island (see fig. 1). The river levels are recorded every 15 minutes at mos

stations; the river level data are then converted to streamflow data. Recorders equipped with telem

(satellite radios or telephone modems) can provide almost immediate access to vital river levels.

Figure 1. Locations of streamflow gaging stations in Massachusetts and Rhode Island

RHODE ISLAND

SOUND

MASSACHUSETTS

RHODE 

ISLAND

42o00’

41o

30’

73o

30’ 73o

00’ 72o

30’ 72o

00’ 71o

30’

71o00’ 70o

3

42o

30’

0 10 20 30 40 50 KILOMETERS

0 10 20 30 40 50 MILES

EXPLANATION

GAGING STATION

TELEMETERED GAGING STATION

U.S. Department of the Interior

U.S. Geological Survey

Reporting of Real Time River Lev

in Massachusetts and Rhode Isla
GOES Satellite

USGS Hydrologic Gaging Station Earth Receiving Station

Data Compilation and Analysis

radio

data line

telephone line

2400 1200 2400 1200 2400 1200 2400 1200 2400 1200 2400

OCTOBER 1996

0

7

1

2

3

4

5

6

CHARLES RIVER AT WALTHAM, MA 01104500

GAGE HEIGHT, 15-MINUTE INTERVAL

2400 1200 2400 1200 2400 1200 2400 1200 2400 1200 2400

19 20 21 22 23

October 1996

7

0

1

2

3

4

5

6

GAGE HEIGHT, IN FEET

CHARLES RIVER AT WALTHAM, MA 01104500

GAGE HEIGHT, 15-MINUTE INTERVAL

Official Telephone Reporting

When a radio cannot be used to 

transmit from a streamflow station 

because of the interference of trees, 

buildings, or mountains within the line 

of sight of the satellite, needed data may 

be retrieved by telephone. Ten 

streamflow stations in Massachusetts 

and Rhode Island are equipped solely 

with telephone modems; an additional 

14 stations are equipped with telephone 

modems and satellite radios. With a 

telephone, officials at USGS, Corps of 

Engineers, National Weather Service, 

and Federal, State, or local flood 

emergency agencies can determine 

what the level of the river is at the time 

the call is made, at any time of day or 

night. If needed, the telephone message 

can provide the level of the river, the 

flow rate, and even what the river level 

was a few hours earlier, so the rate at 

which the river level is changing can be 

determined.

On-Demand Reporting

For rivers that rise rapidly, flood 

warnings based on data 4- to 6-hours old 

may not be timely enough. The same 

recorder that transmits data every 4 hours 

also can be programmed to report more 

frequently, especially when rivers 

approach flood (or drought) levels. “On 

demand” data may be just a few minutes 

old when it is available to officials. 

Instruments with telephone modems also 

can be programmed to call sp

phone numbers with warning

river is approaching unusually 

levels.

USGS Public Web Sit

Current data for 25 of the 

reporting stations are present

on the USGS web site. Histor

streamflow records and groun

also are available at this web 

address of the web site is:

http://mass1.er.usgs.gov

—Russell A. Gadoury

For further information c

tact:

District Chief

U.S. Geological Survey

28 Lord Road, Suite 280

Marlborough, MA 01752

(508)-485-6360

October 1997

Figure 2. Satellite and telephone data transmissions from a streamflow station to a USGS computer.

Figure 4. River level changes at streamflow 

station Charles River at Waltham, MA, responding 

to the flood of October 1996, as reported every 

4 hours in “real time” by satellite radio.

Figure 3. Streamflow station Nas

East Pepperell, MA, with mast fo

gage, and solar panel.