River Condition
Inflow: Warmer Than River
Pixel Statistics
Saturated Pixels: High Mean and Low Variance
Initial Mixing: Larger Areas of Uniform Temperature
Bimodal Distribution with High Variance
Continued Mixing: High Variability in Pixel Values
Decrease in Mean, High Variance
Decrease in Mean and Variance
Mixing Complete: Ambient River Temperature
Table 3. Statistical Analysis Results
. heavy metal contaminated run-off due to mining
operations; and
. run-off from military storage or production facilities, such
as munitions depots, military training areas, motor pools,
or petroleum storage, which carries contaminants into
adjacent bodies of water.
Although the project was successful in demonstrating the utility
of thermal remote sensing as a quick and efficient tool for
mapping temperature patterns of tributary inflows, more work
is planned to fully utilize the datasets for optimizing the Clinch
River Sampling Program. This planned evaluation effort
includes both modeling and “ground truth” work.
Modeling uses three-dimensional techniques, whereas thermal
imagery alone provides only the surface mixing patterns
(essentially two dimensions). The model of choice for this
evaluation is a three-dimensional version of ALGE, a code
developed by Alfred Garrett of Savannah River Technology
Center (SRTC), which solves vertically integrated momentum,
mass, and energy conservation equations to predict the
movement and dissipation of thermal plumes discharged into
cooling lakes, rivers, and estuaries. ALGE was developed
specifically for applications where high resolution is needed
and imagery is available for cell to cell comparisons to code
predictions. The three-dimensional version of ALGE will be
used in this study to capture the effect of deeper and more
turbulent waters. The sensitive parameters of the code include:
plume depth, flow rate, and turbulence. In addition, a sediment
module is under development and will be incorporated to the
three-dimensional code in order to model the movement and
settlement patterns of sediments. Sensitive parameters include:
nature of the sediment, and particle size.
In order to calibrate and validate the mathematical modeling of
the river mixing process, several “ground truth” datasets will be
collected. In addition to validating imagery-based models,
“ground truth” measurements will determine the unique
contribution of imagery-derived data. The experiment will
focus on several parameters of interest including: surface water
temperature, ambient air temperature, vertical profiles of water
temperature and turbidity, river flow and stage data, weather
data, and relevant information on sediment contaminant levels.
Vertical profile measurements (temperature and turbidity) will
be conducted two to three times during the project under a wide
variety of flow conditions at four distinct zones: (1) in the
creek, (2) upstream of mixing zone in the Clinch River, (3) in
the mixing zone, and (4) downstream of the creek/river
confluence (well mixed).
96
4. CASE STUDY: ASSESSMENT OF ROOFTOP
INTEGRITY AT K-25 BUILDINGS
4.1 Introduction
The DOE Oak Ridge K-25 Site is a former DOE uranium
enrichment plant that contains several large process buildings
with roof areas ranging from 20 to 45 acres (8 to 18 hectares).
These buildings have been in place for 40 to 50 years and are
now showing signs of age deterioration many structural
components. For example, the roofs are deteriorating resulting
in large water leaks to the interior and rusting and deterioration
of the metal roof decking. This presents safety concerns for
workers who must walk on roof surfaces and for workers who
work within due to the potential for roof collapse.
Environmental concerns also exist as these former process
buildings are now used as storage areas for hazardous wastes
and should remain dry inside.
To replace or repair all K-25 Site roofs as a single project,
given their large size, would be extremely cost prohibitive. To
effectively address repair and replacement, a logical program of
roof assessment and prioritization is required. Roof site
assessment activities include a variety of tasks such as
determining the current condition of the existing rooftop,
estimating remaining lifetime, evaluating potential for rooftop
collapse, characterizing the rooftop in terms of potential
impacts to human and material safety, determining the need for
roof repair, planning repairs, and performing waste disposal and
management of existing roof materials in the event of roof
repair. A typical roof assessment utilizes a variety of tools such
as infrared thermography, other instrumented non-destructive
moisture sensors, visual inspection and data gathering,
structural integrity analysis, and engineering feasibility analysis
addressing repair and replacement options. For large roofs such
as those at the K-25 Site and numerous other sites within the
DOE complex, use of traditional land-based assessment tools is
lengthy and costly and involves extensive in-situ building
inspection, data gathering, and analysis.
At the K-25 Site, an initial project is currently underway to
investigate the use of non-intrusive remote sensing data in the
characterization of aging rooftops. The project will assess the
utility of remote sensing as a roof screening tool to direct
on-site inspectors to suspect rooftops and roof trouble spots to
minimize cost and maximize efficiency of on-site engineering
assessments. This information is essential to monitor structural
deterioration in order to plan building replacement, to establish
proper building waste material disposal procedures, and to
evaluate potential rooftop failure. The principal focus of this
study will be to determine if remotely sensed thermal signatures
can substitute or supplement ground-based video
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996
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