Small Wars Journal

Desert Walls

Desert Walls

Arnold Hammari

Islamist militant attacks in Tunisia have caused the government to consider building a wall in the desert to keep future attackers out.  38 tourists were killed in Sousse on 26 June 2015 and 22 others were killed at the National Museum in Tunis earlier in March 2015.  These attacks have caused tourists to flee the country and are crushing the tourism economy. 

In response to the flight of tourists 1300 police and armed guards have been deployed to secure tourist sites.  Intelligence reports that the attackers were trained in Libya and entered Tunisia through the porous border.  As a result Tunisian authorities want to build a 100-mile wall along the northern part of the border with Libya to stop the flow of militants into Tunisia.

Tunisian Prime Minister Habib Essid said the country is constructing a wall or berm between the major border crossings of Ras Jedir on the northern coast and Dhehiba 100 miles to the south.  In the future, according to Mr. Essid, they will install an electric fence along the border.  The Prime Minister asserted that the construction of a wall was nothing new as the Americans had constructed a wall along the border with Mexico.

Distant Walls are not the Solution

Unfortunately, the wall will not be cheap and likely not very effective in deterring motivated attackers.  The cost of the construction of the basic wall is estimated at 10 million dinars ($507,885 USD) and the electric fence should cost 150 million dinars ($76,182,737 USD).  It is likely the actual cost of the Tunisian wall or berm will be much more than estimated.  For example, the U.S.-Mexico wall costs on average $1 million per mile.  The Tunisian government has already signaled that it does not have sufficient funds by the project by announcing that it was expecting donations of money and equipment in order to complete the project.  The cost of the wall may be less affordable due to the shocks to the economy from the loss of tourism.

Walls have not been very effective in the past in keeping out insurgents or traffickers.  The Great Wall of China was eventually breached by raiders who destroyed the dynasty.  The French Maginot Line did not stop the Germans from going around the wall in World War II and invading France.  The U.S.-Mexico wall is a modern example of a slightly effective wall as people still manage to go over, under, or even around the wall as it does not traverse the entire border with Mexico. 

The wall between Tunisia and Libya will also not be a complete wall, leaving 200 miles of the frontier unblocked.  The wall in Tunisia will also not be surveilled except at the principal border crossings.  At border crossings and checkpoints corrupt officials and poorly paid police will still let people pass for a fee. 

The envisioned electric fence would need constant power to be effective and many communities away from the large cities and tourist centers have inconsistent or non-existent power.  The Tunisian power grid would need to be upgraded and new infrastructure installed in order to make an electric fence a viable barrier.  It’s likely the new fence materials will be harvested by Bedouins in the less patrolled areas and incorporated into huts and shacks. 

Wall maintenance costs will be high, as the desert conditions will quickly degrade the wall unless it is constantly assessed and repaired.  Theft of materials will add to the cost of the wall as likely it will constantly need to be rebuilt, sections replaced, and foundations reinforced.  The long-term cost of maintaining the wall will easily exceed the initial installation cost.

Protect the City, not the Frontier

A berm or even an electric fence will not stop the traffic from Libya as Tunisia lacks the resources to maintain garrisons along the Libyan border to monitor the entire distance.  Over-watch from unmanned aerial vehicles or cameras with sophisticated sensors would be too expensive for the 300-mile border but the Tunisian government can more likely afford to protect the cities and major tourist centers. 

Ancient cities in the desert had walls with guarded gates to stop attackers and modern day Tunisia can adopt a similar system for much cheaper than a $75 million electric fence across the desert.  The government can build a smaller wall around the city and force traffic to enter through manned checkpoints that are equipped with explosive detecting sensors and bomb dogs to examine the inbound traffic.  A smaller wall can be equipped with cameras and other sensors to detect intruders as well as garrisoned by local police. 

Further out at key intersections checkpoints can interdict attackers on the high-speed avenues of approach.  Overhead imagery from satellites, UAVs, or signals intelligence from radars or other sensors can also provide long distance warning for the cities for cross-country attackers.

Defending less terrain is cheaper and more effective than attempting to guard a wall across a long expanse of the desert.  A wall, berm, or electric fence across the desert along the frontier with Libya will only waste scarce Tunisian resources that could be better used protecting the population and tourist centers.


Move Forward

Wed, 08/05/2015 - 3:31pm

In reply to by Move Forward

Some reality is ingrained in this seemingly wild idea. For instance, I considered the raw material cube’s size at 60” tall and considered that 30” height of stacked plastic 4’ x 4’ sections each one inch thick (30 stacked section each with 16 square feet = 480 square feet) combined with another 30” height of stacked 4’ x 4’ metal-mesh pieces corresponds to the 480 square feet of inch-plus-thick horizontal and vertical surface area that is envisioned per twenty-foot long fence or COP barrier.

Getting combat developers and the Material Command to buy into anything similar is all about recent Iraq and Afghanistan experience and less about protection against armor attack such as the failed Maginot Line. Our inability to secure borders in Iraq and Afghanistan and resultant continuing IED and ambush challenges calls for future solutions.

The ability to move fuel and water via the route fencing pipelines to COPs/Checkpoints along a route and the proposed small rail system for small critical supplies and sensor/weapon movement may or may not be feasible or essential. However, if we want to reduce risky resupply convoys and helicopter airlift while limiting the quantity of expensive remote sensor/weapon systems, such a pipeline and rail system would help. Don’t forget how a water pipeline and remote fire nozzle/sensor on a rail system would assist against forest fires created by climate change and lightning.

Likewise, we should expect future COPs to face insurgents using precision munitions and UAS (provided by adversary neighbors). Therefore, better-than-current top attack and rear protection will be essential against airbursts and rounds landing inside the COP. To get ideas like this moving through the acquisition system is difficult. But the swords <strong>and</strong> plowshares aspect certainly could not hurt, particularly with the National Guard being a key player in the concept for both conflict and peace.

Move Forward

Wed, 08/05/2015 - 3:27pm

Interesting article (edit note: basic wall cost should be $5.08 million). This scenario exemplifies how U.S. external support could finance capabilities that other host nations could not afford—which is money potentially better spent than on development projects. Also, the lack of host nation UAS or costly sensors for long-term surveillance of walls could somewhat be resolved using cheaper sensors to detect activity checked out by a more rare remote sensor/weapon moving on a small rail-system built into the fencing.

While this sounds costly, I’ve read figures for HESCO costs that are pretty alarming ($700 per section?) and concrete T-barriers are a movement and emplacement challenge. 3-D printing likely could reduce costs and allow National Guard construction, to include border and shore barriers to withstand hurricane storm surge, rising sea levels, and flooding. The current cost of border metal fencing (and by extension climate change related construction) illustrates that costs of contracted construction is too high as shown in this author’s link:…

Let me make a case for a notional swords <strong>and</strong> plowshares 3-D printer system mounted on a palletized load system (PLS)/load handling system (LHS) truck’s 20’ x 8’ flatrack:


• Shorter COP barriers with an above-ground trench-like corridor next to dirt-filled barriers complete with overhead protection against airburst and back-of-“trench” support for sandbag protection against shots from behind

• Tall border security fencing or fencing along key corridors with a small elevated rail system carrying mobile sensor/weapon or supplies, and hoses carrying fuel and water for COPs/checkpoints

• Tall city fencing to separate fighting factions and require passage through limited checkpoints


• Tall border fencing along Mexico/Canada constructed by the National Guard

• Shorter shore barriers for protections against hurricane storm surge and rising sea levels from climate change

• Shorter flood barriers for river flooding

• Fire breaks and fire-fighting using the “Swords” elevated hoses carrying water and elevated rail system for moving a mobile fire nozzle/sensor to fire-affected areas

A primary reason for 3-D printer use on a field site is potentially lower costs and the need for customized fencing and barriers on uneven terrain while retaining vertical slats. Vertical slats in the most elevated fence sections would purposely lack upper horizontal cross supports to preclude use of ladders and ropes to climb the fence. 3-D printing using plastic and metal-mesh also reduces the weight of raw fencing materials for truck transport and allows airdrop and sling loads of 2000 pound 4’ x 4’x 5’ raw material cubes for meltdown joining of plastic and metal-mesh shaped to match the terrain.

Using this author’s example of a 300 mile fence yields this potential solution:

• Break it up into three 100 mile sections constructed by three different National Guard crews with separate 3-D printers who provide their own security with augmentation, most likely constructing COPs and checkpoints as they go and staying in them at night during construction.

• Employment of a 3-D printer producing fence sections for each 100 mile section would require 528,000 feet of fencing or 26,400 sections of 20’ long fencing. I’m operating on an assumption that a single 4’ x 4’ x 5’ tall raw material cube can produce one twenty-foot fence/barrier section. Ten such cubes could fit on an 20’ x 8’ flatrack.

• If we wanted to complete the job in 120 days, each crew would need to build 220 twenty-foot long sections of fence per day assuming 10-hour shifts to build .833 miles per day. Actual time would vary depending on the number of 3-D printers, trucks and aircraft for moving cubes, top loaders for filling with dirt, and crews available for construction and security.

• 220 sections per day might require 11 PLS/LHS trucks each carrying ten cubes for melt-down production in the 3-D printer. LHS trucks max out at a 22,000 pound payload so each of ten cubes could weigh only 2,000 pounds. This would mean two round trips a day from the centralized cube source to the 3-D printer truck(s).

• Chinooks could carry up to nine 2,000 pound cubes in three cargo nets or as internal cargo. UH-60Ms and MV-22s could carry three cubes in a cargo net and the K-MAX unmanned systems could carry two cubes. All would fly at night to increase lift and reduce ground fire risk. This and precision airdrop are likely alternatives for complex terrain that would slow or risk conflict truck transport.

• Daily civil or military convoys carrying cubes are another peacetime border and shore construction alternative and option in more secured areas with good trafficability. Lighter plastic and metal-mesh cubes ensure more cubes per truck vs. concrete T-walls, albeit without blast or ballistic protection above dirt-fill levels.

An engineer would come up with a better design but envision a hinged system where to top section either <i>folds up</i> for a 13’ tall border/city/route fence or <i>folds down</i> for a 6’ tall COP security and flood barrier that resembles something like these makeshift diagrams:

The top fence section could be 7’ tall>>> |_ < Horizontal surface w/ pipelines and small rail system.
The bottom fence section could be 6’tall>> |_| <<<< This lower 4’ high by 5’ wide section is dirt-filled. Cables could connect this weighted section to the top barrier to hold it in place.

The COP and flood barrier would resemble the figure below with the top fence section folded down diagonally to create more “trench” room and the overhead cover using either sandbags or add-on armor:

>>>>>>>>>>>> / |_| <<<Lower 4’ height and 5’ wide dirt-filled section stops RPGs and small arms rounds. At COP perimeter corners, the top section could fold up to allow lights or sensors to be mounted 13’ up and troops to gain trench access.