SOUTHWEST 

BORDER SECURITY

CBP Is Evaluating 

Designs and 

Locations for Border 

Barriers but Is 

Proceeding Without 

Key Information

Report to Congressional Requesters

July 2018

GAO-18-614

United States Government Accountability Office
United States Government Accountability Office

Highlights of GAO-18-614, a report to 

congressional requesters

July 2018

SOUTHWEST BORDER SECURITY

CBP Is Evaluating Designs and Locations for Border 

Barriers but Is Proceeding Without Key Information

What GAO Found

In March 2017, U.S. Customs and Border Protection (CBP), within the 

Department of Homeland Security (DHS), issued two requests for proposals 

(RFP) for physical barrier prototype designs for the southwest border. One RFP 

was for prototypes made of reinforced concrete, the other was for prototypes 

made of other materials. CBP subsequently issued task orders, under contracts 

awarded to six companies, to design and construct eight prototypes, pictured 

below. From October to December 2017, CBP tested the prototypes, using a 

range of methods to attempt to climb and breach them. Based on the results, 

CBP identified design attributes it can use to customize future barrier designs for 

specific locations, depending on the terrain and other factors.

U.S. Customs and Border Protection’s Barrier Prototype Designs

CBP and U.S. Border Patrol developed a methodology for prioritizing future 

barrier deployments along the entire southwest border, which included input from 

Border Patrol officials, data on illegal entry traffic, and analysis of operational and 

engineering feasibility for each potential location. However, the strategy did not 

include analysis of the costs associated with deploying barriers in each location 

or segment, which can vary depending on topography, land ownership, and other 

factors. Without assessing costs, consistent with leading practices for capital 

decision making, CBP does not have complete information for prioritizing 

locations to use its resources in the most cost-effective manner.

Acquisitions for the Border Wall System Program—DHS’s program to deploy 

barriers and other assets along the southwest border—are required to follow the 

department’s acquisition process. However, GAO found that for one of the two 

approved segments, DHS has not documented its plans as required. Specifically, 

GAO found that for the Rio Grande Valley segment, DHS leadership approved 

and documented plans in December 2017. In contrast, for the San Diego 

secondary barrier segment, CBP’s plans have not yet been documented, which 

could hinder DHS’s ability to monitor progress for the segment.

View GAO-18-614. For more information, 

contact Rebecca Gambler at (202) 512-8777

or gamblerr@gao.gov.

Why GAO Did This Study

In January 2017, the President issued 

Executive Order 13767, which directs 

the Secretary of Homeland Security to 

immediately plan, design, and 

construct a wall or other physical 

barriers along the southwest border. 

CBP’s fiscal year 2018 appropriation 

provided funding for barrier planning 

and design, but limited use of funds for 

primary barrier construction to 

previously deployed fencing designs. 

GAO was asked to review DHS’s 

efforts to deploy barriers along the 

southwest border. This report 

examines (1) how CBP evaluated 

potential designs for barriers, (2) 

DHS’s process for identifying and 

assessing locations for future 

deployments of barriers, and (3) how 

DHS is managing the acquisition of the 

Border Wall System Program, among 

other things. 

GAO analyzed planning documents; 

interviewed DHS, CBP, and Border 

Patrol officials; and conducted a site 

visit to San Diego to observe CBP’s 

testing of barrier prototypes. This is a 

public version of a sensitive report that 

GAO issued in June 2018. Information 

that DHS deemed sensitive has been 

omitted. 

What GAO Recommends

GAO recommends that DHS analyze 

the costs associated with future barrier 

segments and include that analysis in 

future planning, and document plans 

for the planned secondary barrier 

replacement in the San Diego sector. 

DHS concurred with GAO’s 

recommendations.
Page i GAO-18-614 Southwest Border Security

Letter 1

Background 5

CBP Tested Prototypes to Inform Barrier Designs 13

DHS Selected Initial Locations for Barriers before Identifying 

Priorities across the Southwest Border or Assessing Costs 21

DHS Is Taking Steps to Manage the Acquisition, Technology 

Deployments, and Assessment of the Border Wall System 

Program, but Has Not Documented Plans for One Segment 25

Conclusions 33

Recommendations for Executive Action 33

Agency Comments and Our Evaluation 33

Appendix I Objectives, Scope & Methodology 36

Appendix II Comments from the Department of Homeland Security 39

Appendix III GAO Contact and Staff Acknowledgments 44

Tables

Table 1: U.S. Customs and Border Protection’s (CBP) Planned 

Funding for Southwest Border Barriers, Fiscal Years (FY) 

2017 and 2018 Appropriations and 2019 Funding Request 11

Table 2: Examples of U.S. Customs and Border Protection (CBP) 

Requirements and Test Methods Used for Barrier 

Prototypes 17

Table 3: Summary of Selected Examples of U.S. Customs and 

Border Protection’s (CBP) Barrier Prototype Test and 

Evaluation Results 18

Table 4: U.S. Customs and Border Protection’s Impedance and 

Denial Prioritization Strategy Initial and Final Rankings 23

Figures

Figure 1: Examples of Existing Barriers along the Southwest 

Border 7

Contents
Page ii GAO-18-614 Southwest Border Security

Figure 2: Border Patrol Sectors along the Southwest Border and 

Border Stations and Zones in the Rio Grande Valley and 

San Diego Sectors 8

Figure 3: Department of Homeland Security’s (DHS) Acquisition 

Life Cycle and Acquisition Decision Events 13

Figure 4: U.S. Customs and Border Protection Barrier Prototype 

Designs 15

Figure 5: U.S. Customs and Border Protection’s (CBP) Process 

for Prioritizing Future Barrier Deployments 22

Abbreviations

ADE acquisition decision event 

CBP Customs and Border Protection

DHS Department of Homeland Security

IIRIRA Illegal Immigration Reform and Immigrant Responsibility 

Act

OFAM Office of Facilities and Asset Management

RFP request for proposal 

RVSS Remote Video Surveillance System

S&T Science and Technology Directorate

This is a work of the U.S. government and is not subject to copyright protection in the 

United States. The published product may be reproduced and distributed in its entirety 

without further permission from GAO. However, because this work may contain 

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necessary if you wish to reproduce this material separately.
Page 1 GAO-18-614 Southwest Border Security

441 G St. N.W.

Washington, DC 20548

July 30, 2018

The Honorable Claire McCaskill

Ranking Member

Committee on Homeland Security and Governmental Affairs

United States Senate

The Honorable Bennie Thompson

Ranking Member

Committee on Homeland Security

House of Representatives

The Honorable Filemon Vela

Ranking Member

Subcommittee on Border and Maritime Security

Committee on Homeland Security

House of Representatives

The southwest border of the United States has long been vulnerable to 

cross-border illegal activity. Within the Department of Homeland Security 

(DHS), U.S. Customs and Border Protection’s (CBP) U.S. Border Patrol 

(Border Patrol) is the federal agency responsible for securing U.S. 

borders between ports of entry.1 According to Border Patrol data, in fiscal 

year 2017, Border Patrol agents apprehended 304,000 illegal entrants, a 

decrease from 409,000 in fiscal year 2016.

CBP spent approximately $2.3 billion between fiscal years 2007 and 2015 

to deploy physical barriers along the nearly 2,000-mile southwest border 

and, as of March 2018, maintained 654 miles of primary pedestrian and 

 1

See 6 U.S.C. § 211(a) (establishing CBP within DHS), (c) (enumerating CBP’s duties), (e) 

(establishing and listing duties of U.S. Border Patrol within CBP). Ports of entry are 

facilities that provide for the controlled entry into or departure from the United States. 

Specifically, a port of entry is any officially designated location (seaport, airport, or land 

border location) where DHS officers or employees are assigned to clear passengers and 

merchandise, collect duties, and enforce customs laws, and where DHS officers inspect 

persons entering or applying for admission into, or departing the United States pursuant to 

U.S. immigration and travel controls.

Letter
Page 2 GAO-18-614 Southwest Border Security

vehicular barriers.2 In January 2017, the President issued Executive 

Order 13767, which directs the Secretary of Homeland Security to 

immediately plan, design, and construct a wall or other physical barriers 

along the southwest border.3 In response, CBP initiated the Border Wall 

System Program to plan and deploy new barriers and other assets.4

In prior work, we have reported on the progress DHS has made and 

challenges it has faced in implementing its border security efforts. In

September 2009, we found that CBP had not assessed the impact of 

tactical infrastructure—fencing, gates, roads, bridges, lighting, and 

drainage infrastructure—on border security operations or mission goals.5

Specifically, we found that CBP had not accounted for the impact of its 

investment in border fencing and infrastructure on border security. We 

recommended that CBP conduct an evaluation of the impact of tactical 

infrastructure on effective control of the border.6 In February 2017, we 

found that CBP had not developed metrics that systematically used the 

data it collected to assess the contributions of border fencing to its 

 2

For the purposes of this report, we generally use the term “barrier” to refer to a physical 

structure, such as a pedestrian fence, vehicle barrier, or wall, or any combination of these 

structures, that is intended to impede the movement of people or vehicles. The primary 

barrier, which may include pedestrian or vehicle barriers, is the first barrier encountered 

when moving into the United States from the border; the secondary barrier, located behind 

the primary barrier on the U.S. side of the border, consists solely of pedestrian barrier; and 

the third barrier, or tertiary barrier, is further set back from the border, and is primarily 

used to delineate property lines rather than deter illegal entries.

3

Border Security and Immigration Enforcement Improvements, Exec. Order No. 13767, § 

4, 82 Fed. Reg. 8793, 8794 (Jan. 30, 2017) (issued Jan. 25). Executive Order 13767 

defines “wall” as a “contiguous, physical wall or other similarly secure, contiguous, and 

impassable physical barrier.” See id. § 3, 82 Fed. Reg. at 8794.

4

CBP uses the term “wall system” to describe planned combinations of barriers, separated 

by an enforcement zone; lighting and surveillance technology for the barriers and 

enforcement zone; access roads; and interfaces for current or future technologies to 

support detection capabilities.

5

GAO, Secure Border Initiative: Technology Deployment Delays Persist and the Impact of 

Border Fencing Has Not Been Assessed, GAO-09-896 (Washington, D.C.: Sept. 9, 2009).

6

Prior to 2011, DHS used the number of border miles under “operational control”—also 

referred to as effective control—as its goal and outcome measure for border security and 

to assess resource needs to accomplish this goal. In 2012, Border Patrol transitioned to 

achieving a “low risk border” as its goal and uses a variety of data to assess risk, 

including: threats of cross-border terrorism, drug smuggling, illegal migration across 

locations; integrating border security operations with those of other law enforcement 

partners; and developing rapid response capabilities to deploy the resources appropriate 

to changes in threat.
Page 3 GAO-18-614 Southwest Border Security

mission.7 We recommended that Border Patrol develop metrics to assess 

the contributions of pedestrian and vehicle fencing to border security 

along the southwest border and develop guidance for its process for 

identifying, funding, and deploying tactical infrastructure assets for border 

security operations. CBP concurred with our recommendations and has 

taken action to address them, as discussed later in this report.

You requested that we review DHS’s efforts to deploy barriers along the 

southwest border. In this report, we examine (1) how CBP evaluated 

potential designs for barriers, (2) DHS’s process for identifying and 

assessing locations for future deployments of barriers, and (3) how DHS 

is managing the acquisition, incorporation of technology, and assessment 

of the Border Wall System Program.

This report is the public version of a prior sensitive report that we issued 

in June 2018.8 DHS deemed some of the information in the prior report as 

For Official Use Only, Law Enforcement Sensitive, and Source Selection 

Information, which must be protected from public disclosure. Therefore, 

this report omits sensitive information about CBP’s evaluations of 

potential designs for barriers and Border Patrol’s specific technology 

capabilities. Although the information in this report is more limited in 

scope, the report addresses the same questions as the sensitive report 

and uses the same methodology.

For these objectives, we reviewed relevant documents and met with 

agency officials, including those from the Border Wall System Program 

within CBP’s Office of Facilities and Asset Management (OFAM), Border 

Patrol’s Operational Requirements Management Division, and DHS’s 

Office of Program Accountability and Risk Management. To examine how 

CBP evaluated potential designs for barriers, we visited Border Patrol’s 

San Diego sector, where CBP constructed and tested barrier prototypes. 

We observed prototype testing and toured Border Patrol stations where 

CBP plans to replace existing barriers. We met with Border Patrol officials 

from the San Diego and Rio Grande Valley sectors, where CBP plans to 

construct new barriers, to learn more about their experiences using

 7

GAO, Southwest Border Security: Additional Actions Needed to Better Assess Fencing’s 

Contributions to Operations and Provide Guidance for Identifying Capability Gaps, 

GAO-17-331 (Washington, D.C.: Feb. 16, 2017).

8

GAO, Southwest Border Security: CBP Is Evaluating Designs and Locations for Border 

Barriers but Is Proceeding Without Key Information, GAO-18-489SU (Washington, D.C.: 

June 12, 2018).
Page 4 GAO-18-614 Southwest Border Security

barriers and other assets in their enforcement activities. We also met with 

officials from the U.S. Army Corps of Engineers to learn about their role in 

evaluating the barrier prototypes. In addition, we reviewed key 

documents, including CBP’s prototype test plans and results. To examine 

DHS’s process for identifying and assessing locations for future 

deployments of barriers, we reviewed relevant agency documents such 

as the Border Security Improvement Plan, which includes Border Patrol’s 

priorities for deploying barriers and other assets along the southwest 

border. We also met with DHS and Border Patrol officials and viewed the 

Impedance and Denial Prioritization Strategy that Border Patrol 

developed to inform how the agency prioritized the locations. We 

assessed this methodology against Leading Practices for Capital 

Decision-Making, as well as Border Patrol’s risk assessments and the 

capability gaps Border Patrol identified through its Capability Gaps 

Analysis Process.9 To examine how DHS is managing the acquisition, 

incorporation of technology, and assessment of the Border Wall System 

Program, we reviewed program and acquisition documents prepared for 

the Border Wall System Program and assessed them against DHS 

acquisition policy, implementation guidance, and findings from our 

previous work. Additional details on our scope and methodology are 

contained in appendix I.

We conducted this performance audit from October 2017 through June 

2018 in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 

our findings and conclusions based on our audit objectives. We believe 

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives. We subsequently worked 

with DHS from June 2018 through July 2018 to prepare this public version 

of the original sensitive report for public release. This public version was 

also prepared in accordance with these standards.

 9

GAO, Executive Guide: Leading Practices in Capital Decision-Making, GAO/AIMD-99-32 

(Washington, D.C.: Dec.1, 1998). 
Page 5 GAO-18-614 Southwest Border Security

The Illegal Immigration Reform and Immigrant Responsibility Act (IIRIRA) 

of 1996, as amended, requires the Secretary of Homeland Security to 

take necessary actions to install physical barriers and roads in the vicinity 

of the border to deter illegal crossings in areas of high illegal entry.10 As 

originally enacted, IIRIRA also required the completion of a triple-layer 

fence and road improvements along 14 miles of border near San Diego, 

where Border Patrol had begun installing fence in the 1990s.11 The REAL 

ID Act of 2005 amended IIRIRA by expanding the authority of the 

Secretary of Homeland Security to waive all legal requirements, as 

determined to be necessary, in the Secretary’s sole discretion, to ensure 

expeditious construction of barriers and roads along the border.12

The Secure Fence Act of 2006 amended IIRIRA to require DHS to 

construct at least two layers of reinforced fencing, as well as roads, 

lighting, cameras, and sensors, on certain segments of the southwest 

border in California, Arizona, New Mexico, and Texas.13 The Secure 

Fence Act of 2006 also required that DHS achieve and maintain 

operational control over U.S. borders through surveillance activities and 

physical infrastructure enhancements to prevent unlawful entry by foreign 

nationals and facilitate CBP’s access to the borders.14 Subsequently, the 

DHS Appropriations Act, 2008, rewrote IIRIRA’s border fencing section 

and replaced it with requirements for DHS to construct at least 700 miles 

of reinforced fencing where it would be most practical and effective; and 

to install additional physical barriers, roads, lighting, cameras, and 

 10Pub. L. No. 104-208, div. C, tit. I, subtit. A, § 102(a), 110 Stat. 3009, 3009-554 

(classified, as amended, at 8 U.S.C. § 1103 note). 

11IIRIRA § 102(b), 110 Stat. at 3009-554 to -555. 

12Pub. L. No. 109-13, div. B, tit. I, § 102, 119 Stat. 231, 306.

13See Pub. L. No. 109-367, § 3, 120 Stat. 2638, 2638-2639.

14Pub. L. No. 109-367, § 2, 120 Stat. at 2638 (classified at 8 U.S.C. § 1701 note). 

Executive Order 13767 calls for DHS to obtain complete operational control of the 

southern border, defining operational control as the prevention of all unlawful entries into 

the United States, including entries by terrorists, other unlawful aliens, instruments of 

terrorism, narcotics, and other contraband.

Background

Barriers along the 

Southwest Border
Page 6 GAO-18-614 Southwest Border Security

sensors to gain operational control of the southwest border.15 Under 

IIRIRA, as amended, installation of tactical infrastructure or technology in 

a particular location along the border is not required if the Secretary of 

Homeland Security determines that use or placement of such resources 

is not the most appropriate means to achieve and maintain operational 

control over the border at that location.16

To address these requirements, from fiscal year 2005 through fiscal year 

2015, CBP increased the total miles of primary barriers on the southwest 

border from 119 miles to 654 miles—including 354 miles of primary 

pedestrian barriers and 300 miles of primary vehicle barriers.17 CBP used 

various designs to construct the existing 654 miles of primary fencing. 

See figure 1 for examples of fencing designs currently deployed along the 

southwest border. According to Border Patrol officials, DHS focused its 

deployment of pedestrian barriers near urban areas to divert illegal 

entrants away from densely populated areas, where it is easier for them 

to quickly blend into the surrounding community. Vehicle fencing, which is 

meant to slow and prevent vehicles from crossing the border, is typically 

deployed in more rural environments where, according to Border Patrol 

officials, criminal organizations engaged in trafficking and smuggling use 

vehicles to avoid encountering Border Patrol agents.

 15IIRIRA § 102(b), 110 Stat. at 3009-554 to -555, as amended by Pub. L. No. 110-161, div. 

E, tit. V, § 564(a)(2)(B)(ii), 121 Stat. 1844, 2090-91 (2007) (classified at 8 U.S.C. § 1103 

note).

16Id.

17In addition to the 654 miles of primary fencing, CBP has also deployed additional layers 

of pedestrian fencing behind the primary border fencing, including 37 miles of secondary 

fencing and 14 miles of tertiary fencing. See GAO-17-331.
Page 7 GAO-18-614 Southwest Border Security

Figure 1: Examples of Existing Barriers along the Southwest Border
Page 8 GAO-18-614 Southwest Border Security

Border Patrol divides responsibility for border security operations 

geographically among nine sectors along the southwest border, as shown 

in figure 2. Each sector is further divided into stations, with agents 

assigned to patrol defined geographic areas, or zones, within each 

station. At the end of fiscal year 2017, Border Patrol reported it had 

approximately 16,500 agents staffed to sectors along the southwest 

border.

Figure 2: Border Patrol Sectors along the Southwest Border and Border Stations and Zones in the Rio Grande Valley and San 

Diego Sectors

Border Patrol Operations 

along the Southwest 

Border
Page 9 GAO-18-614 Southwest Border Security

CBP’s Office of Facilities and Asset Management (OFAM) created the 

Border Infrastructure Program Management Office in March 2017. OFAM 

is responsible for overseeing and managing the construction of CBP’s 

tactical infrastructure, including barriers. Under the Border Infrastructure 

Program Management Office’s Border Wall System Program, CBP plans 

to build or replace physical barriers and deploy other infrastructure and 

technology within defined segments along the southwest border.18 CBP 

uses the term “wall system” to describe these planned combinations of 

primary and secondary barriers—separated by an enforcement zone—

together with lighting and surveillance technology for the barriers and 

enforcement zone, access roads, and interfaces for current or future 

technologies to support detection capabilities. Deployments may differ by 

geographical area, due to factors such as variations in the terrain, existing 

resources in the area, and the types of threats present. For example, an 

enforcement zone could be created with the space between a natural 

feature, like a river, and a manmade barrier.

In response to CBP’s fiscal year 2017 budget amendment and request for 

supplemental appropriations, CBP received additional funding in the 

Consolidated Appropriations Act, 2017, to replace existing primary 

pedestrian and vehicle fencing in high-priority areas.19 The act provides 

that the replacement fencing should use previously deployed and 

operationally effective designs that prioritize agent safety.20 CBP plans to 

use these funds for barrier replacement in the San Diego, El Centro, and 

El Paso sectors. In March 2018, the Consolidated Appropriations Act, 

2018, provided CBP $1.34 billion to build or replace primary and 

secondary fencing in the Rio Grande Valley and San Diego sectors, and 

other southwest border locations. The act provides that fiscal year 2018 

funds for new or replacement primary pedestrian fencing are only 

available for operationally effective designs deployed as of May 5, 2017, 

 18Border Patrol officials stated that, as of June 2018, Border Patrol’s Program 

Management Office Directorate was responsible for the Border Wall System Program. 

19The March 2017 request for additional appropriations was made as part of an 

amendment to the President’s fiscal year 2017 budget submitted under the prior 

administration. 

20See Consolidated Appropriations Act, 2017, Pub. L. No. 115-31, div. F, tit. VI, 131 Stat. 

135, 433-34, and accompanying Explanatory Statement, 163 Cong. Rec. H3327, H3823 

(daily ed. May 3, 2017).

Border Wall System 

Program
Page 10 GAO-18-614 Southwest Border Security

such as steel bollard fencing, that prioritize agent safety.21 Table 1 shows 

CBP’s appropriated and requested funding for the construction of new 

and replacement barriers along the southwest border through fiscal year 

2019.

 21See Pub. L. No. 115-141, div. F, tit. II, § 230; 164 Cong. Rec. H2045, H2550, H2557 

(daily ed. March 22, 2018). With respect to secondary fencing, the Consolidated 

Appropriations Act, 2018, specifically required that funding for such fencing in the San 

Diego sector only be used on designs providing cross-barrier visual situational awareness.
Page 11 GAO-18-614 Southwest Border Security

Table 1: U.S. Customs and Border Protection’s (CBP) Planned Funding for Southwest Border Barriers, Fiscal Years (FY) 2017 

and 2018 Appropriations and 2019 Funding Request 

Type of Barrier and Location

Planned Number

of Border Miles 

Amount Appropriated 

or Requested

FY 2017 Appropriationa (funded)

Replacement of primary pedestrian fencing in the 

San Diego sector (California)

14 

$146 million 

appropriated

Replacement of primary pedestrian fencing in the 

El Centro sector (California)

2 

Replacement of primary pedestrian fencing in the 

El Paso sector (Texas) 

4 

Replacement of primary vehicle fencing (to primary 

pedestrian barrier) in the El Paso sector (New Mexico)

20 $146 million 

appropriated

FY 2018 Appropriation (funded)b

Construction of primary pedestrian levee fencing 

in the Rio Grande Valley sector (Texas)

25 $445 million 

appropriated

Construction of primary pedestrian fencing 

in the Rio Grande Valley sector (Texas)

To be determined $196 million 

appropriated

Replacement of secondary pedestrian fencing in the 

San Diego sector (California)

14 $251 million 

appropriated

Replacement of existing primary pedestrian fencing 

along the southwest border 

To be determined $445 million 

appropriated

FY 2019 Funding Requestc

Construction of wall system in the Rio Grande Valley sectord Approximately 65 $1.6 billion requested

Source: GAO analysis of CBP data. I GAO-18-614

Note: Additional funds related to physical border security are not included in this table. For example, 

the Consolidated Appropriations Act, 2017, included $78.8 million for the acquisition and deployment 

of border security technology and $77.4 million for new border road construction. Additionally, the 

Consolidated Appropriations Act, 2018, included $38 million for border barrier planning and design, 

$196 million for the acquisition and deployment of border security technology, and $49.7 million for 

new border road construction.

a

The Consolidated Appropriations Act, 2017, provided funding for the replacement of primary 

pedestrian and vehicle fencing in high-priority areas, using previously deployed and operationally 

effective designs, such as currently deployed steel bollard designs, that prioritize agent safety; and to 

add gates to existing barriers. CBP selected the locations listed.

b

The Consolidated Appropriations Act, 2018, provided funding for secondary fencing in the San Diego 

sector, primary pedestrian (including levee) fencing in the Rio Grande Valley sector, replacement of 

existing primary pedestrian fencing in any location along the southwest border, and border barrier 

planning and design.

c

According to Department of Homeland Security (DHS) officials, the fiscal year 2019 request may be 

modified based on what DHS was appropriated in the Consolidated Appropriations Act, 2018.

d

CBP uses the term “wall system” in reference to planned combinations of tactical infrastructure, 

including primary and secondary barriers separated by an enforcement zone, lighting and 

surveillance technology for the barriers and enforcement zone, access roads, and interfaces for 

current or future technologies to support detection capabilities.
Page 12 GAO-18-614 Southwest Border Security

DHS’s overall policy for acquisition management is outlined in Acquisition 

Management Directive 102-01 and its associated Instructional Manual 

102-01-001.22 DHS’s Under Secretary for Management is currently 

designated as the department’s Chief Acquisition Officer and, as such, is 

responsible for managing the implementation of the department’s 

acquisition policies and acting as the acquisition decision authority for the 

department’s largest acquisition programs.23 The Under Secretary for 

Management is supported by the Office of Program Accountability and 

Risk Management, which is responsible for overseeing the acquisition 

process and assessing the status of acquisition programs through four 

phases of the acquisition life cycle. In addition, the Acquisition Review 

Board, which consists of DHS officials responsible for managing the 

department’s mission objectives, resources, and contracts, provides 

oversight and supports the acquisition decision authority in assessing 

acquisition programs.

The acquisition life cycle includes a series of five acquisition decision 

events (ADE) that provide the acquisition decision authority an 

opportunity to assess whether the program is ready to proceed. DHS 

requires programs to complete certain acquisition documents—such as 

life-cycle cost estimates, test and evaluation master plans, and 

acquisition program baselines—throughout the acquisition life cycle. 

Figure 3 depicts the four phases of the acquisition life cycle and the 

associated ADEs.

 22Department of Homeland Security, Acquisition Management Directive 102-01, Revision 

3 (July 28, 2015). DHS Instruction 102-01-001, Revision 1 (March 9, 2016).

23DHS’s Under Secretary for Management serves as the acquisition decision authority for 

programs with life-cycle cost estimates of $300 million or greater. Component Acquisition 

Executives—the most senior acquisition management officials within each of DHS’s 

component agencies—may be delegated acquisition decision authority for programs with 

cost estimates between $300 million and less than $1 billion and also serve as the 

acquisition decision authority for programs with cost estimates below $300 million.

DHS’s Acquisition Life 

Cycle
Page 13 GAO-18-614 Southwest Border Security

Figure 3: Department of Homeland Security’s (DHS) Acquisition Life Cycle and Acquisition Decision Events

After the issuance of Executive Order 13767 in January 2017, CBP took 

steps to test and evaluate prototypes of new barrier designs for the 

southwest border.24 To fund the planning and design of barriers along the 

southwest border, including the construction and testing of barrier 

prototypes, DHS notified Congress in February 2017 of plans to 

reprogram $20 million from other CBP programs funded in previous 

years.

25 In March 2017, CBP issued two requests for proposals (RFP) for 

 24The Consolidated Appropriations Act, 2018, provided funding for border barrier planning 

and design, but limited the use of funds provided for construction of new and replacement 

primary pedestrian fencing to previously deployed fencing designs. Pub. L. No. 115-141, 

div. F, tit. II, § 230; 164 Cong. Rec. at H2550, H2557.

25These funds were available due to a contract bid protest and delays associated with the 

Mobile Video Surveillance System Program and contract savings from a fence 

replacement project. CBP reprogrammed $15 million from funds originally requested for 

deployments of Mobile Video Surveillance Systems, a technology used by Border Patrol, 

and $5 million from funds originally intended for a fence replacement project in Naco, 

Arizona, which will be completed within its original scope. Of the $20 million in 

reprogrammed funds, approximately $5 million was obligated for prototype construction 

and related support, such as testing and evaluation, site preparations, and security, 

according to CBP officials.

CBP Tested 

Prototypes to Inform 

Barrier Designs

CBP Constructed and 

Tested Barrier Prototypes
Page 14 GAO-18-614 Southwest Border Security

barrier prototypes. One RFP solicited a prototype made of reinforced 

concrete; the second called for a prototype built with other materials, with 

the objective of having a “see-through capability” to facilitate Border 

Patrol agents’ situational awareness of the border.26 CBP subsequently 

awarded task orders to six companies with a total value of over $3 million 

to design and construct eight barrier prototypes.

27 The companies 

constructed the prototypes in the San Diego sector from September to 

October 2017. Four of the prototypes were constructed from reinforced 

concrete, while four included other materials, two of which included a seethrough component, as shown in figure 4.

 26Border Patrol defines situational awareness as the degree to which agents are able to 

perceive and process critical elements of information in the operational environment to 

make effective operational decisions. The RFP calling for the “other border wall prototype” 

required alternatives to reinforced solid concrete walls, which could include, for example, 

different materials or a design that is not entirely solid. The RFP also included threshold 

requirements (intended as minimum requirements) and objective requirements (features 

that CBP determined would substantially enhance the effectiveness of the barrier). One of 

the objective requirements in the RFP calling for a prototype built with other materials was 

to incorporate “a see-through component/capability to the wall that facilitates situational 

awareness”.

27These task orders were issued under an indefinite delivery indefinite quantity contract 

with the potential to compete for future task orders. The prototype task orders met the 

contracts’ minimum guarantee to the companies, so there is no certainty that the 

companies would be selected for potential future task orders. 
Page 15 GAO-18-614 Southwest Border Security

Figure 4: U.S. Customs and Border Protection Barrier Prototype Designs

CBP included 13 requirements in each RFP to guide how the prototypes 

were designed. According to CBP and Border Patrol officials, CBP based 

the requirements on Border Patrol’s approved design requirements for 

existing barriers, along with additional needs identified through 

operational experience. From October to December 2017, CBP’s test 

team tested the prototypes to gather information about how well each met 

the requirements included in the RFPs, grouped into five categories—

breaching, scaling, constructability, engineering design, and aesthetics.28

As established in CBP’s prototype test plan, the evaluation of the 

prototypes was not intended to select a single, winning prototype design, 

 28CBP’s test team consisted of personnel from CBP Office of Acquisition, CBP Operations 

Support, CBP OFAM, Border Patrol, U.S. Army Corps of Engineers, and breaching and 

scaling experts from the Border Patrol Tactical Unit and the U.S. Special Operations 

Command. 
Page 16 GAO-18-614 Southwest Border Security

but rather to inform CBP as it developed new barrier designs. In 

particular, officials from CBP’s test team told us they were more focused 

on learning from industry’s innovations than on identifying potential 

weaknesses in prototype designs, since CBP was not planning to select 

one prototype design to replicate.

As part of its evaluation, CBP’s test team considered a range of common 

and sophisticated methods for attempting to climb and breach each 

prototype barrier. Next, the test team chose which methods would be 

most appropriate for each prototype, since the prototypes varied in 

design. For instance, one testing method was developed by climbing 

experts based on specific features of one of the prototypes, and it was not 

possible to use that particular testing method on the other prototypes.29

CBP’s prototype test plan established the approach and limitations of the 

tests, such as limiting scaling techniques to those that could be 

conducted safely and limiting breaching and scaling techniques to those 

prescribed in the RFP. Table 2 provides examples of the design 

requirements for the prototypes and describes examples of the types of 

testing and evaluation methods CBP used.

 29DHS determined that specific details about the prototype tests are sensitive, so they 

were omitted from this report. 
Page 17 GAO-18-614 Southwest Border Security

Table 2: Examples of U.S. Customs and Border Protection (CBP) Requirements and Test Methods Used for Barrier Prototypes

Test Category 

Design Requirements for the 

Prototypes (Summarized Examples)

Test and Evaluation Methods 

Used (Summarized Examples)

Breaching For concrete prototypes, the design should 

prevent the creation of a hole in the barrier 

larger than 12 inches in diameter using tools 

for a minimum of one hour. For prototypes 

constructed from other materials, the design 

should prevent the creation of a hole in the 

barrier larger than 12 inches in diameter 

using tools for a minimum of 30 minutes.

The CBP test team used various tools to attempt to 

breach prototype “mock-ups,” which were replicas 

of the bottom 10 feet of each prototype. CBP’s test 

team recorded whether they could create a 12-inch 

diameter hole through the prototypes using various 

tools and, if so, how long it took to do so.

Scaling The design should prevent someone from 

“scaling,” or climbing to the top of the barrier 

from either side, without assistance.

The design should include anti-climbing 

features on the top of the barrier that would 

prevent climbing to the top using common 

and more sophisticated tools. 

Climbers on CBP’s test team attempted to reach 

the top of the prototypes during timed tests, both 

unassisted (the climber did not use climbing aids), 

and assisted (the climber used various tools and 

techniques). CBP’s test team recorded whether the 

climber could reach the top of the prototypes in a 

variety of scenarios and, if applicable, how long it 

took to do so. In addition, the test team executed a “perch 

test” to assess whether the prototype’s features allowed 

someone to sit on top of the barrier once they climbed to 

the top. 

Constructability The design should prevent digging for 

a minimum of 6 feet below the lowest 

adjacent grade.

The barrier design should be physically 

imposing in height, and ideally 30 feet tall, 

but no less than 18 feet tall. 

CBP engineers inspected the prototypes to determine 

if they met requirements related to appearance and 

construction. The engineers also assessed how 

feasible it would be to construct the prototypes in 

other environments, based on their observations 

during the construction of the prototypes. 

Engineering Design The design should be cost-effective to 

construct, maintain, and repair.

The barrier design should be constructible 

on slopes up to a 45 percent grade. 

A team from the U.S. Army Corps of Engineers, 

which included civil and structural engineers, 

reviewed design plan documents for each prototype 

and gathered feedback from CBP engineers who 

observed the construction of the prototypes. The 

team conducted cost estimates for the prototypes 

and assessed how well the prototype designs met 

requirements. 

Aesthetics The north side of the barrier should be 

pleasing in color and texture to be 

consistent with the surrounding area.

CBP collected input from 76 personnel on the 

attractiveness and perceived effectiveness of each 

prototype. Engineers from Johns Hopkins University 

developed a test using photographs of the prototypes 

to gather test participants’ ordered preferences. 

Source: GAO analysis of CBP information. | GAO-18-614

Note: This table excludes specific details about test and evaluation methods that DHS deemed 

sensitive.

In February 2018, CBP issued a report describing the prototype test 

results. As intended, the report did not select a winning design or provide 

an overall ranking of the prototype designs. Rather, CBP’s final report 
Page 18 GAO-18-614 Southwest Border Security

included the test team’s detailed assessment of the specific strengths and 

weaknesses presented by each prototype within the five test categories. 

For example, the final report included potential construction challenges, 

factors that facilitated or deterred the team’s attempts to scale or breach 

the prototypes, and feedback from scaling and breaching experts.30 Table 

3 provides a summary of selected prototype test and evaluation results.

Table 3: Summary of Selected Examples of U.S. Customs and Border Protection’s (CBP) Barrier Prototype Test and 

Evaluation Results

Test Category Results As Reported by CBP

Constructability The test team determined that all of the four concrete prototypes would present “extensive” 

construction challenges, especially in a sloping terrain.a Among the four prototypes constructed 

from other materials, CBP determined that two barrier prototypes would present “substantial” 

construction challenges and two would present “moderate” construction challenges. This 

assessment included factors such as whether the foundation would accommodate slope 

changes, distance from the border required during construction, weight of the construction 

materials, and the equipment—such as cranes or concrete trucks—needed during construction.

Engineering Design Six of the eight prototypes would require “substantial” or “extensive” design changes to meet the 

requirement to accommodate surface drainage, and two would require “minimal” changes.

Six of the eight prototypes would require “substantial” or “extensive” design changes to 

accommodate gates needed to provide access to Border Patrol, as required in the request for 

proposal, and two of the prototypes would require “moderate” changes.

Four of the eight prototypes could be constructed at slopes of up to 45 percent, with varying 

degrees of construction challenges. Three of the prototype designs would be impractical for slopes 

over 15 percent. One of the prototypes could not be constructed on any slope without a redesign.

To assess cost-effectiveness, the U.S. Army Corps of Engineers developed cost estimates for the 

prototypes based on the design information submitted by the companies who constructed the 

prototypes. The current working estimate included the estimated contract cost, construction 

contingency, and supervision and administration costs.

Aesthetics CBP identified three prototypes that ranked highest in terms of attractiveness and participants’ 

perception of effectiveness.

Source: GAO analysis of CBP information. | GAO-18-614

Note: DHS determined that specific details about the prototype test results are sensitive, so they are 

omitted from this report.

a

CBP and the U.S. Army Corps of Engineers used the terms “extensive,” “substantial,” “moderate,”

and “minimal” to describe the degree of construction challenges or the changes that would need to be 

made to the design to meet requirements.

As CBP gained more information from test results, its plans for 

developing new barrier designs evolved. In December 2017, CBP officials 

stated that they did not plan to select any single prototype design for 

 30The specific details of the prototype test results that DHS determined are sensitive have 

been excluded from this report. 
Page 19 GAO-18-614 Southwest Border Security

building new barrier segments. Rather, CBP officials stated they planned 

to identify characteristics that improved or weakened the performance of 

the prototypes, and use that information to create new design standards, 

which could include concrete or other materials. In January 2018, after 

viewing preliminary prototype test results, CBP officials told us they 

planned to select design attributes that Border Patrol could use to 

customize the barrier for each planned segment. For example, according 

to CBP and Border Patrol officials, Border Patrol will be able to select the 

materials for the bottom and top halves of the barrier, certain aspects of 

the façade, the height, anti-climb features, and other attributes. CBP and 

U.S. Army Corps of Engineers officials said that there could be limitations 

on how the barrier designs are customized to ensure cost-effectiveness 

or for structural or operational reasons. For example, according to the 

officials, Border Patrol does not plan to use solid concrete on the bottom 

half of a primary barrier, to ensure agents have a clear line of sight to the 

border. In addition, U.S. Army Corps of Engineers officials noted that the 

foundation selected for a barrier design would largely be dictated by the 

surrounding terrain to ensure the structural integrity of the design. Border 

Patrol approved the selected design attributes in February 2018, 

according to OFAM and Border Patrol officials.

While CBP has updated its options for barrier designs, CBP does not plan 

to use these designs for primary barriers to be constructed with fiscal year 

2018 funds, as the appropriations act required that amounts for 

construction of new and replacement primary pedestrian fencing be used 

only for operationally effective designs deployed as of May 5, 2017, such 

as steel bollard fencing.31 CBP officials stated they have always planned 

to use existing barrier designs (bollard-style barriers or levee walls topped 

with bollards) for planned segments in the Rio Grande Valley sector, but 

originally planned to replace about 14 miles of secondary barrier in the 

San Diego sector with a new or modified barrier design. However, in 

March 2018, CBP officials reported that CBP plans to use the existing 

bollard barrier design when constructing the planned secondary barrier in 

the San Diego sector, and that Border Patrol will be able to customize 

some attributes of the barrier informed by the prototype tests, such as the 

height and anti-climb features.

 31See Pub. L. No. 115-141, div. F, tit. II, § 230; 164 Cong. Rec. at H2550, H2557. 
Page 20 GAO-18-614 Southwest Border Security

CBP is developing plans for how it will test and evaluate new barriers and 

other enforcement zone components planned for future deployments. 

CBP officials told us that engineers from CBP and the U.S. Army Corps of 

Engineers would assess any new barrier designs prior to construction to 

ensure the barrier is structurally sound. In December 2017, CBP issued a 

test and evaluation master plan for the Border Wall System Program, 

which describes how CBP plans to assess segments before, during, and 

after construction. CBP’s test and evaluation activities are intended to 

gather information to help DHS and CBP officials identify and minimize 

program risks. Among other things, CBP plans to evaluate how well the 

barriers and other components of the enforcement zone—including 

lighting, access roads, gates, and technology—are expected to meet the 

operational requirements that Border Patrol developed for the Border Wall 

System Program. For example, CBP plans to conduct environmental 

testing designed to assess the performance of the enforcement zone 

components during exposure to adverse environmental conditions.32

CBP plans to develop annexes to the test and evaluation master plan that 

are specific to each planned barrier segment. CBP officials said that the 

annexes will help account for the unique circumstances in each 

geographical area, such as the terrain and proximity to urban settings. In 

January 2018, CBP issued an annex to the test and evaluation master 

plan for the segment planned in the Rio Grande Valley sector. According 

to CBP officials, as of April 2018, CBP continued to develop key 

components of the test and evaluation master plan and its Rio Grande 

Valley annex and was working to complete an annex for the planned 

secondary barrier replacement in San Diego. The test and evaluation 

master plan and Rio Grande Valley annex contain placeholders for a 

range of information, such as the limitations and risks associated with 

testing, criteria to assess reliability of equipment, and location for 

environmental testing. Further, the plans state that these documents are 

meant to evolve, and CBP officials told us they plan to continue to review 

and refine the information with updates expected in September 2018.

 32DHS approved CBP’s Land Systems Operational Test Agency as the Test and 

Evaluation Manager for CBP’s Border Wall System Program. In that role, the Land 

Systems Operational Test Agency will manage cost, schedule, and resources for the 

overall test and evaluation events for the Border Wall System Program. 

CBP Is Developing Test 

Plans for Future Barriers 

and Other Enforcement 

Zone Components
Page 21 GAO-18-614 Southwest Border Security

DHS selected initial locations for new barriers before assessing its 

priorities across the southwest border. In March 2017, CBP selected 

initial locations in the Rio Grande Valley and San Diego sectors for 

inclusion in the fiscal year 2018 budget request, and coordinated with 

DHS’s Office of Program Analysis and Evaluation and the Office of 

Management and Budget as it did so. According to DHS officials, they 

developed the budget request under a condensed time frame, as is 

typical during a change in administration, and, as a result, needed to 

select locations quickly. Officials stated that they examined various 

factors, including information on Border Patrol’s capability gaps, land 

ownership, geography, and data on border incursions. They also stated 

that the administration’s priority was to proceed quickly in constructing 

physical barriers; therefore, land ownership was most important in 

selecting locations for the fiscal year 2018 budget request because 

difficulties in purchasing land could delay barrier construction.

Subsequently, in June and July 2017, OFAM and Border Patrol 

developed the Impedance and Denial Prioritization Strategy, a 

methodology for prioritizing future barrier deployments across the entire 

southwest border. Border Patrol identified a total of 197 segments of 

varying lengths across the southwest border, organized those segments 

into 33 groups, and ranked those groups based on three weighted 

assessments, as shown in figure 5.

DHS Selected Initial 

Locations for Barriers 

before Identifying 

Priorities across the 

Southwest Border or 

Assessing Costs

DHS Selected Initial 

Locations for Barriers 

before Identifying Priorities 

across the Southwest 

Border
Page 22 GAO-18-614 Southwest Border Security

Figure 5: U.S. Customs and Border Protection’s (CBP) Process for Prioritizing Future Barrier Deployments

a

CBP calculates the “Interdiction Effectiveness Rate” by dividing apprehensions + “turn backs” (the 

number of illegal entrants who crossed the border but were not apprehended because they crossed 

back to Mexico) by apprehensions + “turn backs” + “got aways” (the number of entrants who crossed 

illegally and continued traveling to the U.S. interior).

Next, an Operational Review Board composed of Border Patrol subject 

matter experts reviewed and edited the rankings. Border Patrol officials 

stated that the Operational Review Board reviewed law enforcement and 

intelligence information, operational priorities, and Border Patrol strategic 

guidance. According to Border Patrol officials, the Impedance and Denial 

Prioritization methodology prioritized the same segments in the Rio 

Grande Valley and San Diego sectors that DHS had already selected. 

However, our review of the Impedance and Denial Prioritization 

methodology found that it initially identified segments in El Centro, Yuma, 

and Laredo sectors as Border Patrol’s highest priorities for new barriers. 

Table 4 lists the final rankings as published in the strategy and the 
Page 23 GAO-18-614 Southwest Border Security

rankings of those segments based solely on the methodology, prior to 

review by the Operational Review Board. As a result of the board’s 

review, the strategy lists segments in the Rio Grande Valley and San 

Diego sectors as DHS’s highest priorities.

Table 4: U.S. Customs and Border Protection’s Impedance and Denial Prioritization Strategy Initial and Final Rankings

Impedance and Denial 

Prioritization Strategy 

Final Ranking Based on 

Prioritization Methodology and 

Operational Review Board

Initial Ranking 

Based on Prioritization 

Methodology

Segment 

Name

Budget 

Request

1 4 Rio Grande Valley, Group C Fiscal Year 2018

2 5 Rio Grande Valley, Group B Fiscal Year 2018

3 9 Rio Grande Valley, Group A Fiscal Year 2019

4 12 San Diego, Group D Fiscal Year 2018

5 1 El Centro, Group X Not applicable

6 2 Yuma, Group X Not applicable

7 3 Laredo, Group A Not applicable

Source: GAO analysis of Border Patrol data. I GAO-18-614

Border Patrol officials stated that the methodology was intended to serve 

as a starting point for the Operational Review Board’s evaluation, not as 

the sole source for identifying Border Patrol’s priorities. According to 

Border Patrol officials, CBP plans to follow this same process for 

identifying future priorities for border segments. Border Patrol officials 

also told us that they plan to refine the prioritization methodology going 

forward to, for example, account for changes in illegal traffic patterns as 

CBP constructs new barriers.

CBP’s Impedance and Denial Prioritization Strategy did not include an 

analysis of the costs associated with deploying barrier segments. The 

“Operational and Engineering Feasibility” score, which accounted for 20 

percent of total scoring, included an analysis of constructability factors, 

such as hydrology, access, slope, and geophysics, and land acquisition 

details, such as number of tracts and ease of land ownership 

identification. In January 2009, we found that the costs of previous barrier 

deployments along the southwest border varied considerably across 

different locations because of topography and land acquisition costs, 

DHS Did Not Analyze Cost 

When Prioritizing Border 

Segments
Page 24 GAO-18-614 Southwest Border Security

among other factors.33 Further, the U.S. Army Corps of Engineers’

engineering design review of the prototypes found that construction costs 

for the prototype designs would increase as the slope of the terrain 

increased. However, Border Patrol did not assess those costs when 

prioritizing future locations for barrier deployments. The strategy included 

an overall estimate of the cost to construct barriers at Border Patrol’s top 

17 priority locations—an estimate of $18 billion for 722 miles of barriers. 

However, according to CBP officials, that estimate was based on an 

average cost per mile and is not intended to reflect the costs of individual 

construction projects. According to DHS officials, the prioritization 

methodology was not intended to assess costs but rather to identify 

Border Patrol’s operational priorities. DHS plans to assess costs as it 

develops future budget requests. Leading Practices in Capital Decision 

Making states that, when evaluating where to make capital investments, 

organizations should conduct financial analyses in order to prioritize 

investments that allow the organization to obtain the greatest benefits for 

the least cost.34 Without assessing costs as part of the prioritization 

process, CBP does not have complete information to know whether it is 

prioritizing locations that will use its limited resources in the most costeffective manner.

 33GAO, Secure Border Initiative Fence Construction Costs, GAO-09-244R (Washington, 

D.C.: Jan. 29, 2009). 

34GAO/AIMD-99-32. 
Page 25 GAO-18-614 Southwest Border Security

As noted previously, DHS acquisition policy establishes that major 

programs, such as the Border Wall System Program, are subject to 

review by the program’s decision authority at ADEs. These events 

provide the department’s acquisition decision authority an opportunity to 

assess whether the program is ready to proceed, and DHS requires the 

completion of certain documents, such as life-cycle cost estimates, at 

ADEs. For example, under DHS’s acquisition policy, at ADE 1, the 

department is to review the need for the acquisition program. At ADE 2A, 

programs establish an acquisition program baseline that outlines the 

program’s overall schedule, costs, and performance parameters, and 

programs may expand this baseline at ADE 2B, which focuses on 

approval of supporting projects and contracts. As noted below, DHS has 

approved ADE 1 for the overall Border Wall System Program and 

approved ADE 2A/B for one planned segment in the Rio Grande Valley 

sector—one of the two initial planned segments identified by CBP. 

However, DHS has not yet documented its plan for requiring ADE 2A/B 

for the San Diego secondary barrier segment.

• Border Wall System Program. In April 2017, DHS’s acquisition 

decision authority approved the overall Border Wall System Program 

for ADE 1, granting CBP permission to procure the barrier prototypes. 

The approval memorandum also stated that the program would 

deploy new barriers in segments, as prioritized by CBP, and that the 

DHS Acquisition Review Board must assess each segment for a 

combined ADE 2A/B decision to establish baselines and determine 

DHS Is Taking Steps 

to Manage the 

Acquisition, 

Technology 

Deployments, and 

Assessment of the 

Border Wall System 

Program, but Has Not 

Documented Plans 

for One Segment

The Border Wall System 

Program Is Required to 

Follow DHS Acquisition 

Policy
Page 26 GAO-18-614 Southwest Border Security

affordability. Further, DHS officials stated that status updates on the 

Border Wall System Program are provided to the DHS Undersecretary 

for Management in bi-weekly meetings and to the DHS executive 

steering committee during monthly meetings.

• Rio Grande Valley segment. In December 2017, the Acquisition 

Review Board reviewed the program’s Rio Grande Valley segment 

and in January 2018, the acquisition decision authority approved and 

documented the acquisition program baseline and granted ADE 2A/B 

approval.

• San Diego secondary barrier segment. Over the course of our 

review, DHS has changed its position on whether CBP needs to seek 

ADE 2A/B approval for the planned replacement of 14 miles of 

secondary barrier in the San Diego sector. Specifically, in February 

2018, DHS officials told us that this segment did not need an ADE 

2A/B approval because construction for that segment had been 

approved as part of the ADE 1 approval.35 Subsequently, in April 

2018, DHS officials changed their position and told us that the 

segment should follow DHS’s acquisition process and that ADE 2A/B 

approval would be sought within the coming months. As of July 2018, 

DHS had not yet documented its decision to require ADE 2A/B 

approval and follow the DHS acquisition process for the San Diego 

secondary barrier segment. CBP officials stated that DHS planned to 

hold an Acquisition Review Board meeting to review the segment, but 

DHS had not yet scheduled that meeting.

Further, DHS has not yet completed an updated life-cycle cost estimate 

for the San Diego secondary barrier. Consistent with acquisition best 

practices, DHS acquisition policy requires major acquisition programs to 

develop a life-cycle cost estimate at ADE 2A, which is used to establish 

the cost goals in the program’s acquisition program baseline and to 

determine affordability.36 This life-cycle cost estimate should represent 

 35In April 2018, DHS officials also stated that they do not believe that an ADE 2A/B review 

is required because they intend for the San Diego secondary barrier segment to serve as 

a demonstration of how the selected barrier design attributes tested in the barrier 

prototypes would work in border security operations, to assist with refining Border Patrol’s 

requirements and concept of operations for future segments. However, CBP plans to use 

the San Diego secondary barrier in its border security operations, not solely as a 

demonstration. 

36GAO, Homeland Security: DHS Requires More Disciplined Investment Management to 

Help Meet Mission Needs, GAO-12-833 (Washington, D.C.: Sept. 18, 2012). DHS’s 

criteria for assessing cost estimates are based on GAO, Cost Estimating and Assessment 

Guide: Best Practices for Developing and Managing Capital Program Costs, GAO-09-3SP 

(Washington, D.C.: March 2009). 
Page 27 GAO-18-614 Southwest Border Security

the design, performance, and schedule of the system and be updated at 

subsequent ADEs. In July 2017, in response to direction from the House 

Committee on Appropriations, DHS’s Cost Analysis Division initiated an 

independent cost estimate for the barrier construction included in the 

fiscal year 2018 budget request—specifically, the Rio Grande Valley 

segment and San Diego secondary barrier. In October 2017, OFAM 

reviewed the independent cost estimate and adopted it as the program’s 

life-cycle cost estimate, which was used to inform the ADE 2A/B decision 

for the Rio Grande Valley segment. However, the cost estimate for the 

San Diego segment assumes that CBP will replace the secondary barrier 

with a 30-foot concrete barrier. As previously discussed, CBP does not 

plan to deploy a concrete barrier because it would not provide crossbarrier visual situational awareness. CBP officials stated that they plan to 

update the cost estimate to reflect Border Patrol’s design, but as of July

2018, CBP officials had not finalized the document.

We have previously reported on the importance of DHS’s acquisition

programs following the department’s acquisition policy. In September 

2012, we found that DHS’s acquisition policy is generally sound because 

it reflects many key program management practices that could help 

mitigate program risks.37 This policy requires programs to develop 

documents—including acquisition program baselines—that help leaders 

make better informed investment decisions when managing individual 

programs. However, at that time, we also found that DHS was not 

consistently implementing its policy. We recommended that DHS ensure 

all major acquisitions fully comply with the acquisition policy by obtaining 

department-level approval for key acquisition documents before 

approving their movement through the acquisition life cycle. DHS 

concurred with the recommendation, and, in February 2017, we found 

that DHS had approved the required acquisition documentation, including 

acquisition program baselines, for all of its major acquisition programs.38

Requiring that CBP establish an acquisition program baseline and obtain 

ADE 2A/B approval before starting construction for the San Diego 

segment would be consistent with this approach and ensure that DHS 

continues to follow its policy for acquisition programs. Given that the 

department recently changed its plans to require CBP to follow the DHS 

acquisition process for the San Diego secondary barrier segment, 

 37GAO-12-833. 

38GAO, High-Risk Series: Progress on Many High-Risk Areas, While Substantial Efforts 

Needed on Others,GAO-17-317 (Washington, D.C.: Feb. 15, 2017).
Page 28 GAO-18-614 Southwest Border Security

documenting its plans for ADE 2A/B for the San Diego secondary barrier 

segment, including the development of all acquisition documents, would 

help strengthen oversight of the segment going forward and reduce the 

risk of schedule slips and cost growth.

CBP has taken steps to plan for the deployment of technologies to 

enforcement zones that are a part of the Border Wall System Program. 

DHS, CBP, and Border Patrol have emphasized the importance of 

including technology in enforcement zones along with planned barriers. 

For example, in a February 2017 policy memo, the Secretary of 

Homeland Security called for CBP to include technology to support 

barriers as the agency implements Executive Order 13767.39 CBP has 

also reported that technology enhances the effectiveness of barriers by 

improving Border Patrol’s situational awareness and increasing agents’

ability to respond to people approaching the barriers.40 Further, we have 

previously reported that CBP recorded almost 9,300 breaches to existing 

barriers between 2010 and 2015, and Border Patrol has reported that the 

early detection of attempts to cross or breach barriers is critical to 

minimizing damage to barriers and the resulting repair costs.41 In 

November 2017, Border Patrol developed operational requirements 

stating that any barrier design must account for future enhancements of 

technology to support surveillance and detection capabilities.42 In 

addition, Border Patrol’s key performance parameters—the requirements 

CBP will use to assess the performance of the Border Wall System 

 39Department of Homeland Security, Secretary of Homeland Security, Implementing the 

President’s Border Security and Immigration Enforcement Improvements Policies 

(Washington, DC, Feb. 20, 2017). 

40Department of Homeland Security, Customs and Border Protection, Border Security 

Improvement Plan, Fiscal Year 2017 Report to Congress (Washington, DC, Jan. 4, 2018). 

We have previously used the term “surveillance technology” to refer to the technologies—

including cameras, sensors, and radar—CBP has deployed on the southwest border to 

support its domain awareness capability. Border Patrol describes domain awareness as 

ability to continuously detect, identify, classify, and track all border incursions in targeted 

areas at all times. See GAO, Southwest Border Security: Border Patrol Is Deploying 

Surveillance Technologies but Needs to Improve Data Quality and Assess Effectiveness, 

GAO-18-119 (Washington, D.C.: Nov. 30, 2017).

41GAO-17-331, and U.S. Border Patrol, Capability Analysis Report for Customs and 

Border Protection U.S. Border Patrol Impedance and Denial (Washington, D.C.: March 

2017). 

42U.S. Border Patrol, Operational Requirements Document for the Impedance and Denial 

(I&D) Wall System (Washington, D.C.: November 2, 2017).

CBP Is Planning for 

Technology Deployments 

in Border Wall System 

Program Enforcement 

Zones
Page 29 GAO-18-614 Southwest Border Security

Program—include requirements related to technology.43 Specifically, one 

of Border Patrol’s five key performance parameters for the program 

measures the reliability of technology used to support Border Patrol’s 

detection capability within the enforcement zones.44

CBP is coordinating the activities of the Border Wall System Program with 

those of Border Patrol’s Program Management Office Directorate to 

incorporate technology into enforcement zones. Specifically, as part of 

the Border Wall System Program, CBP plans to construct infrastructure to

support technology deployments, such as concrete pads on which a 

tower with surveillance cameras could be mounted, while deploying 

barriers in the Rio Grande Valley and San Diego sectors, according to 

CBP officials. Meanwhile, CBP officials stated that CBP has separate 

acquisition program offices for the specific technologies, which will be 

responsible for procuring and deploying the technologies to support 

surveillance and detection capabilities around barriers.45

For example, in April 2018, DHS, CBP, and Border Patrol officials stated 

that CBP plans to deploy Remote Video Surveillance Systems (RVSS) in 

the Rio Grande Valley sector, beginning with 40 Relocatable RVSS that 

were funded with fiscal year 2017 funds and that will be deployed prior to 

barrier construction.46 Border Patrol officials responsible for the RVSS 

program said they began adjusting their existing deployment plans in the 

Rio Grande Valley sector in June 2017 to coordinate with planned barrier 

 43U.S. Border Patrol, Operational Requirements Document for the Impedance and Denial 

(I&D) Wall System. 

44Specifically, CBP’s acquisition program baseline for the program requires that a wall 

system’s detection capability be operational 95 percent of the time over a 1-year period. 

CBP’s detection systems are considered operational as long as any point within the 

enforcement zone is being monitored by a working detector. 

45DHS determined that specific details about planned technology deployments are 

sensitive, so they are omitted from this report.

46An RVSS system consists of multiple daylight and infrared cameras and a laser mounted 

on poles, towers, or buildings. There are also relocatable versions of the system that are 

mounted on an 80-foot tower, which is mounted on a steel platform trailer and can be 

relocated to other sites. Border Patrol plans to deploy 83 RVSS on fixed towers in the Rio 

Grande Valley sector. Once the fixed RVSS are deployed, CBP plans to move the 

Relocatable RVSS to the next highest priority area. The design and construction of the 

fixed towers received fiscal year 2018 funding, and CBP plans to fund the technology, 

such as cameras and lasers, attached to the towers with fiscal year 2019 and 2020 

funding. In November 2017, we reported on CBP’s progress on deploying RVSS and 

Relocatable RVSS to Texas and other locations. See GAO-18-119. 
Page 30 GAO-18-614 Southwest Border Security

deployments, once locations in the sector were prioritized for the Border 

Wall System Program. CBP officials stated that they have synchronized 

the schedules for all of the relevant acquisition programs for the Rio 

Grande Valley sector, but are still working on plans for how they will work 

together operationally. The officials told us that CBP intends that 

Relocatable RVSS will be deployed by the time barriers are constructed, 

with the intent that Border Patrol agents will be able to monitor the 

information collected from the deployed technologies, such as video 

feeds from the RVSS cameras. For the secondary barrier planned in the 

San Diego sector, officials told us CBP plans to use the existing 16 RVSS 

already deployed in the San Diego sector.

CBP’s efforts to incorporate technology are in the planning stages, and 

CBP is still determining specific technology needs and how it will integrate 

the technology with future barrier segments. For example, as part of the 

DHS acquisition process, DHS’s Science and Technology Directorate 

(S&T) assessed the program from August through November 2017 to 

provide information to the acquisition decision authority, such as the 

technical maturity of the planned technology and overall technical risk. 

Specifically, S&T assessed CBP’s plans to integrate the planned 

technologies in the Rio Grande Valley sector and to transmit the data 

collected from the technologies to Border Patrol agents engaged in 

monitoring activities. S&T found that CBP had not clearly defined or 

planned for the integration and operation of technologies, such as 

enforcement zone cameras and video displays. Among other things, S&T 

recommended establishing the activities and timeline needed for 

integrating camera sensors, video displays, and supporting capabilities 

for the first planned segment in the Rio Grande Valley sector. In April 

2018, CBP officials told us that they have efforts under way that will 

address S&T’s recommendations and are still considering options for how 

they will integrate the planned technologies.

In addition, DHS has requested $1.6 billion for fiscal year 2019 to deploy 

65 miles of new barriers in the Rio Grande Valley sector. CBP officials 

stated they are still determining the specific technology needed to support 

these planned barriers and how it will be funded. Given that CBP is 

currently determining specific technology needs for future barrier 

segments and considering options for integrating that technology, it is too 

early to assess the extent to which CBP’s plans will effectively use and 

integrate technology with barriers planned for the Border Wall System 

Program.
Page 31 GAO-18-614 Southwest Border Security

According to CBP officials, the agency plans to review barriers 

constructed under the Border Wall System Program, and is taking steps 

to assess the results of previous investments in barriers and surveillance 

technology, which could inform future deployments. DHS’s systems 

engineering life cycle framework, which supports the department’s 

acquisition process, is meant to ensure the efficient and effective delivery 

of the capabilities in which DHS has invested.47 Among other things, the 

framework requires that all DHS programs conduct a post-implementation 

review 6 to 18 months after a program has reached initial operating 

capability. The post-implementation review is designed to determine how 

well investments are meeting their baseline performance, cost, and 

schedule goals. In addition, a post-implementation review is meant to 

identify and document deployment problems, how they were resolved, 

and how the issues could be prevented in the future. However, according 

to OFAM and Border Patrol officials, the requirement to conduct a postimplementation review was not established until 2009 when the systems 

engineering life cycle framework was established, so CBP was not 

required to conduct the reviews for previous tactical infrastructure 

deployments, including barriers. OFAM and Border Patrol officials stated 

they captured some lessons learned in 2007 and 2008 during previous 

deployments of barriers. For example, they assessed how well access 

gates installed in barriers were performing and identified deployment 

issues for both the barriers and gates. However, their assessments of the 

barrier projects did not capture how the barriers were meeting the Border 

Patrol’s specific operational needs and addressing capability gaps, as 

post-implementation reviews are designed to do. CBP officials stated that 

they plan to conduct post-implementation reviews for barriers constructed 

under the Border Wall System Program, as required in the systems 

engineering life cycle framework.

Further, our previous work on barriers and surveillance technology 

included recommendations intended to strengthen CBP’s ability to assess 

the results of previous investments. In February 2017, we recommended 

that Border Patrol develop metrics to assess the contributions of 

 47Department of Homeland Security, Systems Engineering Life Cycle 102-01-103 

(November 5, 2015). Systems Engineering Life Cycle Guidebook 102-01-103-01 (April 18, 

2016). The DHS systems engineering life cycle framework identifies the activities that 

constitute a structured, disciplined, and quality technical effort and establishes a series of 

activities and technical reviews, such as the post-implementation reviews, to assess the 

technical readiness of the program to proceed beyond its current activity. 

CBP Has Plans to Assess 

the Border Wall System 

Program, and Is Taking 

Steps to Assess Previous 

Investments in Barriers 

and Technology
Page 32 GAO-18-614 Southwest Border Security

pedestrian and vehicle fencing to border security along the southwest 

border using the data Border Patrol already collects and apply this 

information, as appropriate, when making investment and resource 

allocation decisions.48 The agency concurred with our recommendation, 

and officials reported that CBP plans to finalize metrics in January 2019. 

With respect to surveillance technology, in March 2014, we 

recommended that CBP (1) require data on technology contributions to 

apprehensions or seizures to be tracked and recorded within its database 

and (2) subsequently analyze available data on apprehensions and 

technological assists—in combination with other relevant performance 

metrics or indicators, as appropriate—to determine the contribution of 

surveillance technologies.49 CBP concurred with our recommendations, 

and in November 2017, we reported that Border Patrol had made 

progress identifying performance metrics for the technologies deployed 

along the southwest border.50 Specifically, Border Patrol agents collected 

and reported data on the instances in which technologies contributed to 

an apprehension or seizure. In addition, Border Patrol reported it is 

developing the Tracking, Sign Cutting, and Modeling system to allow for 

more comprehensive analysis of the contributions of surveillance 

technologies to Border Patrol’s mission.51 However, in February 2018, 

Border Patrol officials stated they are not yet able to fully assess 

surveillance technologies and their impact on border security operations. 

We continue to believe that by fully implementing our prior 

recommendations, Border Patrol will be able to better assess the 

contributions of existing barriers and technologies deployed along the 

southwest border and consider this information when making future 

border security investments.

 48GAO-17-331. 

49GAO, Arizona Border Surveillance Technology Plan: Additional Actions Needed to 

Strengthen Management and Assess Effectiveness, GAO-14-368 (Washington, D.C.: Mar. 

3, 2014). For the purposes of this report, apprehensions include individuals arrested and 

identified as potentially removable aliens by Border Patrol. Seizures include Border Patrol 

apprehensions of drugs, currency, and weapons, among other things. A technological 

assist occurs when a technological asset, such as a remote video surveillance system, 

contributes to apprehensions or seizures. 

50GAO-18-119.

51CBP officials said that the system is intended to use data collected by Border Patrol to 

draw connections between agents’ actions (such as identification of a subject with a 

camera) and results (such as an apprehension). 
Page 33 GAO-18-614 Southwest Border Security

DHS plans to spend billions of dollars developing and deploying new 

barriers along the southwest border. However, by proceeding without key 

information on cost, acquisition baselines, and the contributions of 

previous barrier and technology deployments, DHS faces an increased 

risk that the Border Wall System Program will cost more than projected, 

take longer than planned, or not fully perform as expected. Without 

assessing costs when prioritizing locations for future barriers, CBP does 

not have complete information to determine whether it is using its limited 

resources in the most cost-effective manner and does not have important 

cost information that would help it develop future budget requests. 

Without documenting plans to require CBP to follow the DHS acquisition 

process for the San Diego barrier segment, DHS may not establish cost, 

schedule, and performance goals by which it can measure the program’s 

progress. In addition, Border Patrol should continue to implement our 

prior recommendations to assess the contributions of existing barriers

and technologies deployed along the southwest border and consider this 

information when making future border security investments.

We are making the following two recommendations to DHS:

The Commissioner of CBP should analyze the costs associated with 

future barrier segments and include cost as a factor in the Impedance and 

Denial Prioritization Strategy. (Recommendation 1)

The Under Secretary for Management should document plans to require 

CBP to follow the DHS acquisition life cycle, including the completion of 

all acquisition documentation requirements, for the planned secondary 

barrier deployment in the San Diego sector. (Recommendation 2)

We provided a draft of this report to DHS for review and comment. In its 

written comments, which are reproduced in full in appendix II, DHS 

concurred with the two recommendations and described actions planned 

to address them. DHS also provided technical comments that we 

incorporated, as appropriate. We also provided a draft of this report to the 

Department of Defense, which declined to comment.

DHS concurred with our first recommendation to analyze the costs 

associated with future barrier segments and include cost as a factor in the 

Impedance and Denial Prioritization Strategy. DHS stated that it has been 

and will continue to include cost as part of the capital investment process 

Conclusions

Recommendations for 

Executive Action

Agency Comments 

and Our Evaluation
Page 34 GAO-18-614 Southwest Border Security

for the Border Wall System Program. Specifically, DHS stated that CBP 

will first select locations for new barrier segments based on operational 

priorities, then assess cost to determine a design configuration for those 

segments. For example, DHS stated that CBP developed a life-cycle cost 

estimate for planned barrier segments in the Rio Grande Valley sector 

and is developing a life-cycle cost estimate for the planned barrier 

segment in the San Diego sector. DHS also stated that it balances 

resource requests across components as part of the annual budget 

process. We agree that it is important for DHS to develop life-cycle cost 

estimates for planned barrier segments as part of the acquisition process. 

However, Leading Practices in Capital Decision-Making, which are 

intended to enhance the effectiveness of federal investments in capital 

assets, states that, when evaluating where to make capital investments, 

organizations should conduct financial analyses in order to prioritize 

investments that allow the organization to obtain the greatest benefits for 

the least cost. In order to fully address our recommendation, CBP needs 

to ensure that it analyzes costs as part of the prioritization process when 

evaluating potential barrier segments. DHS also stated that our report 

suggests that CBP should base its priorities on a budget, rather than on 

what users determine are operationally high-risk areas. Our report does 

not state that CBP should base its priorities on a budget. Rather, we 

believe that evaluating cost as part of the prioritization process, in 

accordance with Leading Practices in Capital Decision-Making, would 

provide DHS more complete information to develop future budget 

requests that address operational needs while using resources in the 

most cost-effective manner.

DHS also concurred with our second recommendation to document its 

plans to require CBP to follow the DHS acquisition life cycle, including the 

completion of all acquisition documentation requirements, for the planned 

secondary barrier deployment in the San Diego sector. However, DHS 

asserted that our report states that CBP is not following DHS acquisition 

policy, with which DHS disagreed. Our report does not state that CBP is 

not following DHS acquisition policy; rather, the report states that DHS is 

following DHS acquisition policy but has not yet documented its plan for 

requiring ADE 2A/B for the planned secondary barrier segment in the San 

Diego sector. With respect to our recommendation, DHS stated it plans to 

complete all DHS acquisition policy requirements and documentation 

before returning to the DHS Acquisition Review Board for ADE 2A/B 

approval for all barrier segments under the Border Wall System Program, 

including the planned secondary barrier in the San Diego sector. DHS 

plans to complete these activities for the San Diego barrier segment by

September 30, 2018. These actions, if implemented effectively, should 

address the intent of our recommendations.
Page 35 GAO-18-614 Southwest Border Security

As agreed with your offices, unless you publicly announce the contents of 

this report earlier, we plan no further distribution until 7 days from its issue 

date. At that time, we will send copies to the appropriate congressional 

committees, the Secretary of Homeland Security, and the Secretary of 

Defense. In addition, the report will be available at no charge on the GAO 

website at http://www.gao.gov.

Should you or your staff have questions about this report, please contact 

me at (202) 512-8777 or gamblerr@gao.gov. Contact points for our 

Offices of Congressional Relations and Public Affairs may be found on 

the last page of this report. GAO staff that made key contributions to this 

report are listed in appendix III.

Rebeca Gambler

Director

Homeland Security and Justice
Appendix I: Objectives, Scope & Methodology

Page 36 GAO-18-614 Southwest Border Security

This report examines (1) how U.S. Customs and Border Protection (CBP) 

evaluated potential designs for barriers along the southwest border, (2) 

the Department of Homeland Security’s (DHS) process for identifying and 

assessing locations for future deployments of barriers, and (3) how DHS 

is managing the acquisition, incorporation of technology, and assessment 

of the Border Wall System Program.

This report is the public version of a prior sensitive report that we issued 

in June 2018.1 DHS deemed some of the information in the prior report as 

For Official Use Only, Law Enforcement Sensitive, and Source Selection 

Information, which must be protected from public disclosure. Therefore, 

this report omits sensitive information about CBP’s evaluations of 

potential designs for barriers and Border Patrol’s specific technology 

capabilities. Although the information in this report is more limited in 

scope, it addresses the same questions as the sensitive report. The 

overall methodology used for both reports is the same.

To examine how CBP evaluated potential designs for barriers, we visited 

U.S. Border Patrol’s San Diego sector, where CBP constructed and 

tested barrier prototypes. We viewed the barrier prototypes, observed 

CBP’s breaching tests on prototype mock-ups, and met with CBP officials 

responsible for the construction and testing of the prototypes to learn 

about how the tests were developed and their plans for evaluating the test 

results. During the site visit, we also met with Border Patrol officials from 

the San Diego sector headquarters and the Chula Vista and Imperial 

Beach stations to learn more about their experiences deploying and using 

barriers and other assets to conduct their enforcement activities. We also 

toured about 14 miles of the southwest border in Chula Vista and Imperial 

Beach stations, where CBP plans to replace primary and secondary 

pedestrian barriers. We also met with Border Patrol officials in the Rio 

Grande Valley sector headquarters and the Rio Grande City, McAllen, 

and Weslaco stations, where CBP plans to construct barriers, to discuss 

their experiences using barriers and other assets to support enforcement 

activities. We reviewed relevant documents, including the requests for 

proposals CBP issued for the prototypes, the resulting task order 

contracts, CBP’s prototype test plan and test results, and CBP’s test and 

evaluation master plan, and assessed the information against DHS 

acquisition policy and guidance. We met with officials from CBP’s Office 

 1

GAO, Southwest Border Security: CBP Is Evaluating Designs and Locations for Border 

Barriers but Is Proceeding Without Key Information, GAO-18-489SU (Washington, D.C.: 

June 12, 2018). 

Appendix I: Objectives, Scope & 

Methodology
Appendix I: Objectives, Scope & Methodology

Page 37 GAO-18-614 Southwest Border Security

of Facilities and Asset Management, including the program manager for 

the Border Wall System Program to discuss how the prototype test results 

influenced CBP’s decisions about the designs of barriers planned to be 

constructed along the border and how CBP will continue to evaluate the 

barriers and supporting assets prior to, during, and after construction. We 

also viewed CBP’s video recordings of the climbing tests used to evaluate 

the prototypes. We met with officials from Border Patrol’s Operational 

Requirements Management Division and the U.S. Army Corps of 

Engineers to learn about their roles in the development and evaluation of 

the prototypes.

To examine DHS’s process for identifying and assessing locations for 

future deployments of barriers, we reviewed relevant documents, such as 

the Border Security Improvement Plan, which includes Border Patrol’s 

priorities for deploying barriers and other assets along the southwest 

border. During meetings with Border Patrol, we also viewed the 

Impedance and Denial Prioritization Strategy that Border Patrol 

developed to prioritize locations, to learn more about the criteria Border 

Patrol used and how the information was weighted to provide rankings of 

locations along the southwest border. We assessed this methodology 

against Leading Practices for Capital Decision-Making, as well as Border 

Patrol’s risk assessments and documentation of Border Patrol’s 

Capability Gaps Analysis Process.2 In addition to those offices already 

noted, we also spoke with officials from DHS’s Budget Office, Cost 

Analysis Division, and Office of Program Analysis and Evaluation to learn 

more about how initial locations were selected when CBP made fiscal 

year 2018 funding requests for planned segments.

To examine how DHS is managing the acquisition, incorporation of 

technology, and assessment of the Border Wall System Program, we 

reviewed relevant program and acquisition documents for the Border Wall 

System Program, including CBP’s budget requests and program cost 

estimates, DHS’ Science and Technology Directorate’s letter of technical 

assessment, and Border Patrol’s operational requirements document. 

During our meetings with CBP and Border Patrol officials, we discussed 

updates on program funding, cost estimates, and how the deployment of 

barriers and other assets would be coordinated to meet program 

objectives. In addition to those offices already described, we also met 

 2

GAO, Executive Guide: Leading Practices in Capital Decision-Making, GAO/AIMD-99-32 

(Washington, D.C.: Dec.1, 1998). 
Appendix I: Objectives, Scope & Methodology

Page 38 GAO-18-614 Southwest Border Security

with officials from DHS’s Office of Program Accountability and Risk 

Management and Science and Technology Directorate to learn more 

about their roles in performing acquisition and program management 

oversight. We compared DHS and its components’ efforts against 

documented CBP and Border Wall System Program objectives, DHS 

acquisition policy and implementation guidance, and findings from our 

previous work.

We conducted this performance audit from October 2017 through June 

2018 in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 

our findings and conclusions based on our audit objectives. We believe 

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives. We subsequently worked 

with DHS from June 2018 through July 2018 to prepare this public version 

of the original sensitive report for public release. This public version was 

also prepared in accordance with these standards. 
Appendix II: Comments from the Department 

of Homeland Security

Page 39 GAO-18-614 Southwest Border Security

Appendix II: Comments from the Department 

of Homeland Security
Appendix II: Comments from the Department 

of Homeland Security

Page 40 GAO-18-614 Southwest Border Security
Appendix II: Comments from the Department 

of Homeland Security

Page 41 GAO-18-614 Southwest Border Security
Appendix II: Comments from the Department 

of Homeland Security

Page 42 GAO-18-614 Southwest Border Security
Appendix II: Comments from the Department 

of Homeland Security

Page 43 GAO-18-614 Southwest Border Security
Appendix III: GAO Contact and Staff 

Acknowledgments

Page 44 GAO-18-614 Southwest Border Security

Rebecca Gambler, gamblerr@gao.gov, (202) 512-8777

In addition to the contact named above, Jeanette Henriquez (Assistant 

Director), Ashley Davis, Aryn Ehlow, Eric Hauswirth, Sasan J. “Jon”

Najmi, Alexis Olson, Claire Peachey, and Leslie Sarapu made key 

contributions to this report.

Appendix III: GAO Contact and Staff 

Acknowledgments

GAO Contact

Staff 

Acknowledgments

(102823)
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