tom mckenna1, jack puleo2, and aline pieterse3 · tom mckenna1, jack puleo2, and aline pieterse3...

Thermal imaging of Hydrologic Processes in Streams and Wetlands in the Delaware Estuary Watershed,

Delaware and Pennsylvania

Tom McKenna1, Jack Puleo2, and Aline Pieterse3

University of Delaware 1Delaware Geological Survey & Dept. of Geological Sciences

2Center for Applied Coastal Research & Dept. of Civil and Envtl. Eng. 3Department of Geological Sciences & Center for Applied Coastal Research

Center for Applied Coastal Research

Hydrologic Processes Water Cycle

wetland

tidal wetland

gw Q

stream

Reflected Solar Energy

1.7µm 3.0µm 5.0µm 14.0µm 8.0µm 1.0µm

SWIR MWIR LWIR NIR

0.4µm

UV Visible

Emitted Environmental Energy (Thermal Infrared)

All materials at temperatures greater than absolute zero emit detectable electromagnetic radiation. Very hot objects (like the sun) emit radiation in the visible region. Cooler objects (like the earths surface or human body) emit radiation in the thermal band of the electromagnetic spectrum.

ENVIRONMENTAL THERMOGRAPHY Using a thermal-imaging radiometer as a diagnostic tool

Key Principles

• The distribution of temperature in the environment can be used to characterize hydrology because fluid flow and heat transfer are highly coupled processes.

Key Principles


•Water has a higher thermal inertia than soil, sediment, and vegetation, so it takes longer to heat up or cool down given the same environmental conditions.

Key Principles


•Water has a higher thermal inertia than soil, sediment, and vegetation, so it takes longer to heat up or cool down given the same environmental conditions.

• Surface waters and soils encounter different environmental conditions than groundwater flowing deeper underground.

Key Principles even more

• Ground water at depths greater than a few meters usually has a temperature close to the mean annual air temperature.


• Ground water at depths greater than a few meters usually has a temperature close to the mean annual air temperature. • Heat is transferred in the environment by conduction, convection, and radiation.


• Ground water at depths greater than a few meters usually has a temperature close to the mean annual air temperature. • Heat is transferred in the environment by conduction, convection, and radiation.

•The radiant temperature is a function of target temperature, emissivity, background temperature, and air temperature/humidity.

Groundwater discharging to wetlands, surface water, or the land surface can result in distinct temperatures signals.

Water Temperature

0

5

10

15

20

25

30

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Tem

pera

ture

(C)

Breakwater HarborPhiladelphia

groundwater

Delaware Bay

Delaware River

Imaging Platforms

Used for this presentation

Mill Creek Elsmere

New Castle County Delaware

Thermal Imaging Survey of Chestnut Run to determine locations of groundwater discharge. McKenna, Asreen (DNREC), Sollenberger, and Petrov; February 20, 2013.

Walking survey

Mill Creek, Site 7

Thermal Imaging Survey of Chestnut Run to determine locations of groundwater discharge. McKenna, Asreen, Sollenberger, and Petrov; February 20, 2013.

X

X

X

Subsequent pore water samples contained contaminants of concern


Mill Creek Site 8


Mill Creek Site 10



Mill Creek, Site 18 from bridge looking downstream

Mill Creek, Site 18 looking upstream

Thermal discharge from a pipe outfall (>18 deg C in winter)

White Clay Creek tributary with source in Carpenter Recreation Area, Site 8N3-2B seep

New Castle County, Del

3/27/2014 9:30 am

at seep Tk = 8.0 oC

at confluence with Reach 8

Tk = 4.4 oC

White Clay Creek tributary with source in Carpenter Recreation Area, Site 8-14

3/25/2014 ~11:05 am

New Castle County, Del

Why is creek not frozen when others visited were partially frozen? Large man-made springs!

White Clay Creek tributary, Reach 1, New London Road

WALKING SURVEY I-495 ditch

tidal channel, low tide

Reaches

Thermal Imaging Survey of I-495 tidal ditch to determine locations of groundwater discharge at Halby Chemical / Potts Property McKenna, Cargill, Keyser, Greer, and Durski; February 14, 2013

Reach A: Christina R. to Christiana Ave. (~152m [500Fft]) Reach B: Christiana Ave. to RR tracks (~168m [550ft]) Reach C: RR tracks to Terminal Ave. (~305m [1,000ft])

2007 Terminal Ave.

Site A2 and upstream visual thermal

Site A2 groundwater

discharge

upstream no

groundwater discharge


A2 5579-5593


Groundwater Discharge at Site A2

11 °C 3

Warm seepage into this marsh indicates a ground-water source.

What visually appears to be a spring is a cold “re-appearing” stream.

Identifying Sources of Water in Wetlands

Freshwater Marsh Preserve, Rockland, Delaware (walking survey, winter, early morning)

13οC

1οC

Relatively warm water is flowing in very shallow channels obscured by dense, matted vegetation. The source of this warmer water is discharge from the “re-appearing” stream at the upland fringe of the wetland.

Delineating Surface Water Flowpaths in a Wetland

Freshwater Marsh Preserve, Rockland, Delaware (walking survey, winter, early morning)

or “on-line staring at the river”

Thermal, NIR, and visual imagers mounted on temporary radio tower

Field of View

Wolf River, Mississippi, May 2010

Temporal Thermal Imaging to Determine River Velocity

low gradient , coastal plain, sand-bed river Center for Applied Coastal Research

Visual image

May 26, 2010, 3:30 pm CDT Wolf River, Mississippi


One thermal image from a 5-minute sequence of images collected at 4 Hz.

May 26, 2010, 10 pm CDT (night). Wolf River, Mississippi


Velocity of surface water shown as vectors overlain on a georectified thermal image.

Visual (later in day)

Sequences of thermal images and image velocimetry algorithms are used to determine river velocity.

24.5 26 ºC

t = 0 sec

t = 5 sec

t = 10 sec

1 m

thermal

Water is flowing from left to right (springtime; 4:30 am local time)

Tidal inundation of marshes

“Discrepancies in tidal phase and elevation in a numerical model can be accommodated by the modeling calibration process but can severely limit the explanatory power and predictive capabilities of the model.” (French, 2003)

The flow of water on salt marsh platforms is still poorly characterized.

marsh platform

secondary tidal channel

upland

primary tidal channel

Challenges: very dynamic system microtopography dense vegetation

A A

B

B

channels are “hot” (yellow)

inundated platform is “warm” (orange)

Image of Marsh Platform Inundation warmer water flowing onto cold marsh surface

Brockonbridge Marsh December 13, 2008 high spring tide cold morning (subfreezing) helicopter platform

Delaware Bay

Thermal Imaging of Tidal Marsh Inundation

Warmer water (orange) flowing onto colder marsh surface (purple). The extent of inundation is clear in the thermal image but is ambiguous in the visual image due to remnant water on the marsh and similarity between turbid water and mudflats.

March 10, 2009 high spring tide cold morning UD Airship

thermal

visual


25 m high

Tidal Flooding of a Salt-Marsh

South Bowers, Delaware June 23 & 24, 2009

8pm-11pm

Relatively warmer water flooding over colder marsh surface

Bowers Beach

Tide

Temperature

9:45 pm

10:00 pm

10:15 pm

10:30 pm

10:43 pm

June 24, 2009 South Bowers, Delaware Thermal imaging from bucket lift Time series of tide flooding a salt marsh One hour sequence Relatively warmer water flooding over colder marsh surface

Thermal Imaging of Inundation

Tide Temperature

25 m high

11:34 pm

11:10 pm

10:45 pm

Visual image taken on following morning

South Bowers, Delaware June 23 & 24, 2009

8pm-11pm

Relatively warmer water ebbing from a colder marsh surface

12 18 °C 6:34 DST

60

7:34 DST

120

5:49 DST

15

6:04 DST

30

6:19 DST

45

8:04 DST

150

8:19 DST

165 min 135

7:49 DST

90

7:04 DST

105

7:19 DST

sunrise

5:34 DST

0 min flood tide

75

6:49 DST

high tide ebb tide

Cooler water from the Delaware Bay flows into a tidal channel during flood tide and back out during ebb tide (May 2008) visual

Brockonbridge Marsh Delaware Wildlands property


View from tower

Cooler tidal water (blue) floods a warmer (yellow-green) tidal mudflat

26-minute time series of thermal images at 2 minute intervals; Tidal flow enters from a channel to the right of the images

Red is surrounding salt marsh that was not flooded. South Bowers, Delaware; March 2013

Results of algorithm that tracks waterline during a flood tide for three different fields of view.

Survey sled during active surveying. The second operator is to the left and out of the field of view.

In Situ data collection

In Situ

J. A. Puleo, A. Pieterse, and T. E. McKenna, in press, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

Digital Elevation Model

Image Derived

Note: Elevation in surrounding salt marsh (dark blue) in both images is from in situ RTK survey.

Absolute value of elevation difference between image-derived and measured topography

J. A. Puleo, A. Pieterse, and T. E. McKenna, in press, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

Histogram of absolute error

Error Analysis

CONCLUSIONS • Environmental thermography with a thermal-imaging radiometer can be used as a

diagnostic tool when studying hydrologic processes.

• Handheld and fixed location surveys can be done.

• Groundwater discharge locations can be identified (subaerial and subaqeuous) provining locations where representative water samples can be taken.

• Stream velocity can be measured.

• Preferential flowpaths can be traced in wetlands.

• Sources of water to wetlands can be determined.

• Bathymetry can be mapped on intertidal flats.

tom mckenna1, jack puleo2, and aline pieterse3 · tom mckenna1, jack puleo2, and aline pieterse3...

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