NWIRP Research Study of Hurricane Maria 

(Puerto Rico)

Infrastructure Systems Supporting Critical Buildings 

and Emergency Communications

Project Leader: Ken Harrison

NCST Advisory Committee Meeting, June 8-9, 2022
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Background and Motivation: Resilience

“The term ‘resilience’ means the ability to prepare 

for and adapt to changing conditions and 

withstand and recover rapidly from disruptions.” 

-Presidential Policy Directive/PPD-21, 2013

Prior to 

Disruption

•Prior codes, 

standards and 

practice

After 

Disruption

•Direct and 

indirect 

impacts

Function 

recovered

•Can operate 

as before the 

disruption

Resilience 

Restored

•Ability to 

withstand and 

recover is 

restored

Resilience 

Improved

•New codes, 

standards, 

and practice
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Background and Motivation: Importance of Dependencies 

on the Support of Critical Buildings

Cell Sites Out-of-Service 10/21/17, by Municipio (%)

Transportation incidents: Hurricanes Irma/Maria

Hospitals and high-capacity water, power, and transportation links

• To minimize the loss and time to recovery of 

infrastructure support of critical buildings, it is 

important to understand dependencies between 

infrastructure systems
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Power

Communications

Transportation

Water

Dependencies

Wireless 

Communications

Objective: Investigate 

causes of the loss of 

functionality and 

extended-duration outage 

of the wireless 

communication system in 

Puerto Rico following 

Hurricane Maria

Objective: Evaluate 

dependencies in power, 

water, and transportation 

infrastructure impacts, 

recovery, and 

decision-making

Transportation Incident 

Analysis

Objective: Mine the PR 

DTOP Transportation 

Incident Database to 

answer HM program 

questions

Integrative Study

Objective: In a case study 

for a community in Puerto 

Rico, evaluate the 

potential for model 

support of resilience 

decision-making

Project Plan: Five Project Components

Vegetation Remote-Sensing

(new project component)

Objective: Apply remote-sensing data to relate 

vegetation condition and infrastructure resilience
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• Motivation

• Transportation: incident analysis: at least 

1/3 of road incidents from debris

• Power: DOE findings & recommendations 

pertaining to vegetation1:

• Transmission: trouble accessing 

transmission corridors

• Distribution: vegetation management 

would have been “...decisive factor 

limiting the extent of damage...”

• Satellite remote-sensing data: tree 

canopy cover (TCC)

• Landsat-based from USFS (30 m maps 

available for 2011 & 2016)

• MODIS-based (250 m; annual maps for 

2000-2020)

New Project Component: Vegetation Remote Sensing

[1] Energy Resilience Solutions for the Puerto Rico Grid 

(2018) (U.S. Department of Energy (DOE)).

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Example of greater resolution of Landsat 30 m (top; a map of change 

in TCC from 2011 to 2016) and MODIS 250 m TCC for one year (2017)
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•New data product: 3-yr, 5-yr composited TCC from MODIS 

(250 m; right)

• Value added: temporal compositing needed due to data quality 

issues as indicated by per-pixel MODIS quality flags

• Compositing: on a per-pixel basis, select the observation flagged 

with the highest available quality.

2013

2017

2019

Recent Progress: Vegetation Remote-Sensing

Correlation of Landsat 30 m with native MODIS 250 m called attention to 

potential quality issues, motivating image compositing.
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• Identified additional imagery sources

• Assessed available aerial imagery for 

efficacy at capturing tower damage

• Created geoprocessing model to 

extract images of cell towers from 

high-resolution post-storm imagery

• Used model to extract images for four 

categories of towers from FCC 

dataset (738 towers):

• Free-standing or guyed structure

• Lattice tower

• Mast

• Monopole

• Analyzed extracted images and 

identified additional collapsed and 

damaged towers

Recent Progress: Wireless Communications 

Credit: NOAA
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Power

Communications

Transportation

Water

Dependencies

Wireless 

Communications

• Continue to analyze 

aerial imagery to 

categorize all towers as 

either:

• Collapsed

• Still 

standing--observable 

damage

• Still standing--no 

observable damage

• Determine design codes 

and hazard levels 

(modeled wind speeds) 

for each tower 

• Geospatially analyze 

tower performance as a 

function of hazard levels 

and code requirements

Structured interview 

instruments through IRB, 

PRA, with fully developed 

sampling frame

Transportation Incident 

Analysis

Quality control in 

consultation with DTOP

Integrative Study

Extend ARC model to include 

schools, businesses

Project plan: Next Steps

Vegetation Remote-Sensing

• 30-m tree cover focal analyses

• Smaller infrastructure study areas
NWIRP Research Study of Recovery from 

Hurricane Maria’s Impacts on Puerto Rico

Infrastructure Systems Supporting Critical Buildings and 

Emergency Communications

Project Leader: Ken Harrison

Project Team: Marc Levitan (NIST), Jazalyn Dukes (NIST), Jordan Borak 

(PREP Research Associate, University of Maryland), Nicholas de Toledo (PREP 

Research Associate, University of Maryland), Zeinab Farahmandfar (PREP 

Research Associate, Johns Hopkins University)

NCST Advisory Committee Meeting, June 8-9, 2022