Leveraging Existing Watershed Models

for Flood Forecasting Purposes

FSA 2018 Annual Conference

Sanibel Harbour Marriott

Fort Myers, Florida (June 13 – 15)

Peter J. Singhofen, P.E.

Streamline Technologies, Inc.

psinghofen@icpr4.com

2 © 2018, Streamline Technologies, Inc.

Hurricane Irma Flooding

Altamonte Springs

Leveraging Existing Watershed Models for Flood Forecasting

3 © 2018, Streamline Technologies, Inc.

Hurricane Irma Flooding

Westside Manor, Orange County

Leveraging Existing Watershed Models for Flood Forecasting

4 © 2018, Streamline Technologies, Inc.

Tropical Storm Debby Flooding

Suncoast Parkway, Hernando County

Leveraging Existing Watershed Models for Flood Forecasting

5 © 2018, Streamline Technologies, Inc.

1. Can existing watershed models be leveraged

for flood forecasting purposes?

2. Are reliable and reasonably accurate forecast

data readily available?

3. Can the process be automated?

Detailed watershed models are available

for each of the previous examples

Leveraging Existing Watershed Models for Flood Forecasting

6 © 2018, Streamline Technologies, Inc.

Completed

SWFWMD

floodplain

mapping

(mostly with

ICPR models)

Orange County

ICPR watershed

models

The State of Florida

is data rich.

Extensive

infrastructure

inventories and

models are available

across the state,

including hundreds

of ICPR models.

Leveraging Existing Watershed Models for Flood Forecasting

7 © 2018, Streamline Technologies, Inc.

The National Water Model (NWM)

Leveraging Existing Watershed Models for Flood Forecasting

8 © 2018, Streamline Technologies, Inc.

National Water Model

Gridded Forcing Data Products (Rainfall)

Near Real Time (72 files per day)

Present Time Minus 1 Hour (Radar Only)

Present Time Minus 3 Hours (Gauge Adjusted)

Short Range Forecast (432 files per day)

Forecast Duration: 18 hours in 1-hour Increments

Forecast Frequency: Every hour

Medium Range Forecast (960 files per day)

Forecast Duration: 10 days in 1-hour Increments

Forecast Frequency: Every 6 hours

Leveraging Existing Watershed Models for Flood Forecasting

9 © 2018, Streamline Technologies, Inc.

How Does it Work?

NWM DATA

REPOSITORY MOST RECENT

24-HR PERIOD

DATA

RETRIEVAL APP PRE-PROCESS

NWM DATA

HOURLY

UPLOAD

HOURLY

PURGE (FIFO)

HOURLY

DOWNLOAD

HOURLY UPDATE

REDUCED

DATASET TO

LOCAL MODEL

HOURLY

PURGE (FIFO)

Leveraging Existing Watershed Models for Flood Forecasting

10 © 2018, Streamline Technologies, Inc.

How Does it Work?

Base Model

Short Range Forecast Model

Medium Range Forecast Model

Leveraging Existing Watershed Models for Flood Forecasting

11 © 2018, Streamline Technologies, Inc.

Rainfall Accuracy (Irma)

Near Real Time Rainfall Comparison

Radar Only strong and consistent low bias

Gauge Adjusted some improvement, but minimal

Leveraging Existing Watershed Models for Flood Forecasting

12 © 2018, Streamline Technologies, Inc.

Rainfall Accuracy (Irma) Short Range Forecast Comparison

18 Hours Ahead of Peak Flood Levels overall correlation is very poor

(R2 = 0.05)

Leveraging Existing Watershed Models for Flood Forecasting

13 © 2018, Streamline Technologies, Inc.

Rainfall Accuracy (Irma) Medium Range Forecast Comparison

3 Days Ahead of Peak Floods overall correlation is poor

(R2 = 0.20)

2 Days Ahead of Peak Floods overall correlation is good

(R2 = 0.66)

Leveraging Existing Watershed Models for Flood Forecasting

14 © 2018, Streamline Technologies, Inc.

Example: Little Wekiva River Watershed

• Highly urbanized watershed in

Orange and Seminole Counties

(54.3 square miles)

• No changes to H&H

• Model setup steps

1. Import ICPR3 project to ICPR4

2. Georeference hydraulic data

3. Import basin map layer

4. Import NWM fishnet map layer

5. Intersect basins & fishnet

Leveraging Existing Watershed Models for Flood Forecasting

15 © 2018, Streamline Technologies, Inc.

Example: Little Wekiva River Watershed

Leveraging Existing Watershed Models for Flood Forecasting

16 © 2018, Streamline Technologies, Inc.

Example: Little Wekiva River Watershed

Simulated Flood Extents During

Hurricane Irma

Leveraging Existing Watershed Models for Flood Forecasting

17 © 2018, Streamline Technologies, Inc.

Example: Little Wekiva River Watershed

FORECASTS ISSUED:

SEPT. 08 at 0800 hrs

SEPT. 09 at 0800 hrs

SEPT. 10 at 0800 hrs

Rain Gauges

Short Range

Forecast

Medium Range

Forecasts

Hurricane Irma

Leveraging Existing Watershed Models for Flood Forecasting

18 © 2018, Streamline Technologies, Inc.

Example: Little Wekiva River Watershed

Surveyed

HWM Base Model

FORECASTS ISSUED:

SEPT. 08 at 0800 hrs

67 hrs

Medium Range

Forecast

Hurricane Irma

Leveraging Existing Watershed Models for Flood Forecasting

19 © 2018, Streamline Technologies, Inc.

Example: Little Wekiva River Watershed

Surveyed

HWM

FORECASTS ISSUED:

SEPT. 09 at 0800 hrs

43 hrs

Medium Range

Forecast

Hurricane Irma

Base Model

Leveraging Existing Watershed Models for Flood Forecasting

20 © 2018, Streamline Technologies, Inc.

Example: Little Wekiva River Watershed

Surveyed

HWM

FORECASTS ISSUED:

SEPT. 10 at 0800 hrs

19 hrs

Short Range

Forecast

Hurricane Irma

Base Model

Leveraging Existing Watershed Models for Flood Forecasting

21 © 2018, Streamline Technologies, Inc.

Example: Little Wekiva River Watershed

SR

43

6

Hurricane Irma

Leveraging Existing Watershed Models for Flood Forecasting

22 © 2018, Streamline Technologies, Inc. Leveraging Existing Watershed Models for Flood Forecasting

• No changes to original basic H&H data

• Model uses curve number method and does

not include groundwater, consequently it

cannot be used for continuous simulation

• It is very fast and good for approaching storm

systems

< 30 secs for short range forecast

5 – 6 mins for medium range forecast

Example: Little Wekiva River Watershed

23 © 2018, Streamline Technologies, Inc.

Example: Alligator Creek Watershed

• Highly urbanized watershed in

Pinellas County

• 8.6 square miles

• Replaced percolation links with

2D groundwater

Leveraging Existing Watershed Models for Flood Forecasting

24 © 2018, Streamline Technologies, Inc.

Example: Alligator Creek Watershed

HW 19

GAUGE

KAPOK

GAUGE

ALLIGATOR

CREEK

Leveraging Existing Watershed Models for Flood Forecasting

25 © 2018, Streamline Technologies, Inc.

Example: Alligator Creek Watershed

Observed

ICPR4

Hurricane

Irma ~ 10 days

Leveraging Existing Watershed Models for Flood Forecasting

26 © 2018, Streamline Technologies, Inc.

Example: Alligator Creek Watershed

Short Range

Forecast Observed

Medium Range

Forecasts

FORECASTS ISSUED:

SEPT. 08 at 0800 hrs

SEPT. 09 at 0800 hrs

SEPT. 10 at 0800 hrs

Hurricane Irma

Leveraging Existing Watershed Models for Flood Forecasting

27 © 2018, Streamline Technologies, Inc.

Example: Alligator Creek Watershed

Short Range

Forecast

Observed

Medium Range

Forecasts

FORECASTS ISSUED:

SEPT. 08 at 0800 hrs

SEPT. 09 at 0800 hrs

SEPT. 10 at 0800 hrs

Hurricane Irma

Leveraging Existing Watershed Models for Flood Forecasting

28 © 2018, Streamline Technologies, Inc.

Example: Alligator Creek Watershed

Short Range

Forecast

Observed

Medium Range

Forecasts

70 hrs

46 hrs

19 hrs

Hurricane Irma

Leveraging Existing Watershed Models for Flood Forecasting

29 © 2018, Streamline Technologies, Inc.

Example: Westside Manor, Orange County

Hurricane Irma Flooding

30 © 2018, Streamline Technologies, Inc.

Example: Westside Manor, Orange County

Hurricane Irma Flooding

Leveraging Existing Watershed Models for Flood Forecasting

31 © 2018, Streamline Technologies, Inc.

Example: Westside Manor, Orange County

Simulated Flood Extents

Hurricane Irma

Pump

Station

Leveraging Existing Watershed Models for Flood Forecasting

32 © 2018, Streamline Technologies, Inc.

Example: Westside Manor, Orange County Medium Range Forecasts Issued at 8:00 a.m. EDT

Rainfall Comparison

Leveraging Existing Watershed Models for Flood Forecasting

33 © 2018, Streamline Technologies, Inc.

Example: Westside Manor, Orange County Medium Range Forecasts Issued at 8:00 a.m. EDT

Stage Comparison

Recorded High Water

80.7 ft NAVD88

Leveraging Existing Watershed Models for Flood Forecasting

34 © 2018, Streamline Technologies, Inc.

Example: Westside Manor, Orange County Short Range Forecasts Issued Sunday, September 10th

Rainfall Comparison

Leveraging Existing Watershed Models for Flood Forecasting

35 © 2018, Streamline Technologies, Inc.

Example: Westside Manor, Orange County Short Range Forecasts Issued Sunday, September 10th

Stage Comparison

Recorded High Water

80.7 ft NAVD88

Leveraging Existing Watershed Models for Flood Forecasting

36 © 2018, Streamline Technologies, Inc.

Example: Braden River Watershed Manatee & Sarasota Counties, Florida

59 square miles

Leveraging Existing Watershed Models for Flood Forecasting

37 © 2018, Streamline Technologies, Inc.

Braden River Watershed Short Range Forecast Hurricane Irma

Forecast Issued:

Sunday Sept. 10, 2017

at 0800 EDT

Leveraging Existing Watershed Models for Flood Forecasting

38 © 2018, Streamline Technologies, Inc.

Braden River Watershed Short Range Forecast Hurricane Irma

Leveraging Existing Watershed Models for Flood Forecasting

39 © 2018, Streamline Technologies, Inc.

Observed

Medium Range

Forecasts

Hurricane Irma

Braden River Watershed

Short Range

Forecast

Leveraging Existing Watershed Models for Flood Forecasting

40 © 2018, Streamline Technologies, Inc.

Observed

Medium Range

Forecasts FORECASTS ISSUED:

SEPT. 08 at 0800 hrs

SEPT. 09 at 0800 hrs

SEPT. 10 at 0800 hrs

Hurricane Irma

Braden River Watershed

Leveraging Existing Watershed Models for Flood Forecasting

41 © 2018, Streamline Technologies, Inc.

Observed

Medium Range

Forecasts

(24 hrs apart)

Hurricane Irma

Braden River Watershed

77 hrs

53 hrs 29 hrs

Leveraging Existing Watershed Models for Flood Forecasting

42 © 2018, Streamline Technologies, Inc.

Observed

Short Range

Forecasts

(2 hrs apart)

Braden River Watershed

29 hrs

Leveraging Existing Watershed Models for Flood Forecasting

43 © 2018, Streamline Technologies, Inc.

Base Run

Medium Range

Forecasts

Braden River Watershed

August 26th

Storm

IRMA

Leveraging Existing Watershed Models for Flood Forecasting

44 © 2018, Streamline Technologies, Inc.

Base Run

Medium Range

Forecasts

Braden River Watershed

IRMA

August 26th

Storm

Leveraging Existing Watershed Models for Flood Forecasting

45 © 2018, Streamline Technologies, Inc.

Another Source for Forecast Data NWS Southeast River Forecast Center

Leveraging Existing Watershed Models for Flood Forecasting

1st 6 hours 2nd 6 hours 3rd 6 hours

46 © 2018, Streamline Technologies, Inc.

What’s Next?

• Continue testing National Water Model data

for the 2018 hurricane season

• Begin testing NWS Southeast River Forcast

Center data for the 2018 hurricane season

• Automate the entire process

Leveraging Existing Watershed Models for Flood Forecasting

47 © 2018, Streamline Technologies, Inc.

Closing Thought

Leveraging Existing Watershed Models for Flood Forecasting

Try to imagine a single

forecasting model for the

entire State of Florida, built

upon the hundreds of existing

detailed models already

available.

It is definitely in the realm of

possibilities!

48 © 2018, Streamline Technologies, Inc.

Thank you!

Peter J. Singhofen, P.E.

Streamline Technologies, Inc.

psinghofen@icpr4.com

Leveraging Existing Watershed Models for Flood Forecasting