1. INFLOWS
INTEGRATED FLOOD OBSERVATION AND WARNING
SYSTEM
WHAT IS IT?
• REAL-TIME DATA COLLECTION AND
FLOOD WARNING SYSTEM
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2. INFLOWS
INTEGRATED FLOOD OBSERVATION AND WARNING
SYSTEM
HISTORY
• HURRICANE AGNES JUNE 1972. PRECIPITATION WAS 6 INCHES A DAY. JAMES
RIVER VIRGINIA CRESTED 36.5 FEET, HIGHEST IN 200 YEAR (VDEM, 2014).
DAMAGE: 1400 HOMES; ROADS, BRIDGES DESTROYED; 13 PEOPLE KILLED;
COST OF DAMAGE AMOUNTED TO $325 MILLION.
• DEVASTATING FLOODING OF 1977 AFFECTED KENTUCKY, VIRGINIA AND WEST
VIRGINIA. NATIONAL WEATHER SERVICE (NWS) INITIATED NATIONAL FLASH
FLOOD DEVELOPMENT IN 1978, INFLOWS DEVELOPED FROM THIS AS JOINT
EFFORT WITH STATES.
• PROTOTYPE STARTED 1980, 12 COUNTIES ON THE APPALACHIAN,
SUSCEPTIBILITY TO FLOODING (VDEM, 2014).
• 1985, CONGRESS APPROVED NWS INFLOWS FUNDING; EXPAND TO COVER
BEYOND INITIAL 7 STATES. LINKED AND INTEGRATED DATA AND
INFORMATION THROUGH 250 COMPUTERS; 1500 SENSORS; 12 STATES AND
120 COUNTIES.

3. INFLOWS
INTEGRATED FLOOD OBSERVATION AND WARNING
SYSTEM
OBJECTIVES:
 STRENGTHEN STATE’S MITIGATION
CAPACITY
 REDUCE:
 LOSS OF LIFE
 PROPERTY DAMAGE
 LIMIT DISRUPTION OF ECONOMIC
ACTIVITIES
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4. INFLOWS
INTEGRATED FLOOD OBSERVATION AND WARNING
SYSTEM
HOW THE SYSTEM WORKS
• COMPOSED OF NETWORK:
 SENSORS
o STREAM GAUGE: PRESSURE TRANSDUCER,
RESERVOIR. DEPTH TRANSMITTED VHF
o RAIN GAUGE: PIPE, SCREENED FUNNEL, TIPPING
BUCKET, 0.04 INCH, COUNTS TRANSMITTED VHF
 POWER SOURCE: SOLAR POWER
 TWO-WAY RF COMMUNICATIONS
(TRANSMITTER, REPEATER, RECEIVER),
 SOFTWARE (OS AND DATABASE)
 HARDWARE (COMPUTERS SYSTEMS)
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5. INFLOWS
INTEGRATED FLOOD OBSERVATION AND WARNING
SYSTEM
HOW THE SYSTEM WORKS
• NOTE:
• HARDWARE AND SOFTWARE
DEPLOYED FROM DIFFERENT
VENDORS.
• PRIVATELY OWNED AND RUN
SYSTEMS CAN BE ALLOWED READ-
ONLY ACCESS FROM INFLOWS
NETWORK (INSTITUTIONS,
RESEARCHERS, AGENCIES).
IMAGES FROM

6. INFLOWS
INTEGRATED FLOOD OBSERVATION AND WARNING
SYSTEM
VIRGINIA INFLOWS
JOINT PROGRAM:
• NWS AND VIRGINIA DEPARTMENT OF EMERGENCY MANAGEMENT (VDEM)
AND LOCAL AUTHORITIES.
ROLES
 NWS
 PROGRAM MANAGEMENT, NATIONALLY
 FUNDING (SOFTWARE DEVELOPMENT, COMMUNICATION DESIGN,
CAPITAL COSTS (COMPUTERS, TRANSMITTERS, SENSORS, RAIN GAUGES ETC.).
 VDEM
 PROGRAM MANAGER AND ASSISTANT (COORDINATION)
 O & M OF CENTRAL COMPUTERS
 LOCAL AUTHORITIES
 FLASH FLOOD COORDINATOR
 PREMISES FOR COMMUNICATION EQUIPMENT
 EMERGENCY RESPONSE PLAN

7. INFLOWS
INTEGRATED FLOOD OBSERVATION AND WARNING
SYSTEM
VIRGINIA INFLOWS
 35 LOCAL AUTHORITIES
 282 RAIN SENSORS
 80 STREAM SENSORS
PROTOCOL
 DATA TRANSMITTED REAL-TIME TO COUNTY
LOCATIONS COMPUTERS. DATA PROCESSED AND
(VDEM, 2014).
OPTIONS
 STAND ALONE
 INTEGRATED; SEND INFLOWS DATABASES BY VSP
MICROWAVE SYSTEM, STATE & NATIONALLY

8. INFLOWS
INTEGRATED FLOOD OBSERVATION AND WARNING
SYSTEM
RAPIDAN RIVER WATERSHED
INFLOWS
LOCATION
• RAPIDAN RIVER AT ROUTE 29
• ROBINSON RIVER AT ROUTE
29

9. INFLOWS
INTEGRATED FLOOD OBSERVATION AND WARNING
SYSTEM
INFLOWS LIMITATIONS
COST (PURCHASE, INSTALLATION, O & M)
TECHNOLOGY CHANGE
FAILURE (CALIBRATION, DISTURBANCE-
CAUSED)

10. REFERENCE
Virginia Department of Emergency Management, 2014. Integrated Flood Observing and Warning
Systems (IFLOWS). Web site
http://www.vaemergency.gov/content/integrated-flood-observing-and-warning-systems-iflows
U.S. Army Corps of Engineers, 2013. Upper and Middle Rappahannock River Report 2013.
http://www.nao.usace.army.mil/Portals/31/docs/business/FPMS/PASDocuments/App_A_4a.pdf