Terre Arch™
Modular Stormwater Detention System

Overview

If you are looking for an underground stormwater detention system that is cost-effective, easy to install, and will last a lifetime, then look no further than the Terre Arch™ Modular Stormwater Detention System from Terre Hill Concrete Products. The Terre Arch™ System is scalable to suit a wide array of site parameters and storage requirements. And because each unit is made from precast concrete, the Terre Arch™ System is strong enough to support greater loads with minimal cover.

Use our Online Project Calculator to see if the
Terre Arch™ System will work for your next project.

DISCOVER THE TERRE ARCH™ ADVANTAGE

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EASE AND SPEED OF INSTALLATION
Each Terre Arch™ section installs in just a few minutes, allowing you to create up to 25,000 cubic feet of storage per day, reduce installation time, and minimize labor expenses.
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DURABILITY AND LONGEVITY
Plastic and metal systems cannot compete with the lasting strength of precast concrete. If you need a system that will stand the test of time, you need a Terre Arch™ system.
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IDEAL FOR HIGH WATER ELEVATIONS
With its modular, low-profile design, Terre Arch™ can be installed where other systems cannot.
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MINIMAL COVER REQUIRED
Achieve maximum strength with minimal cover thanks to Terre Arch’s™ distinctive “Roman Arch” design.
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ECO-FRIENDLY
Concrete products are made from naturally derived materials and are produced in local manufacturing facilities.

Specifications
CAD/PDF
Plan Notes
FAQ

WHICH UNDERGROUND BASIN IS RIGHT FOR YOU?

Terre Arch™ TA26 Information Sheet (PDF) | Terre Arch™ TA48 Information Sheet (PDF)

	StormTech ® SC-740	Terre Arch™ TA26	StormTech ® MC-3500	Terre Arch™ TA48
Stone Base	6”	6”	9”	12”
Stone Between Units	6”	None	9”	None
Minimum Cover	24”	12”	24”	12”
Dimensions per unit	L: 7.12’ W: 4.25’ H: 2.50’	L: 8.00’ W: 19.00’ H: 2.83’	L: 7.17’ W: 6.42’ H: 3.75’	L: 8.00’ W: 20.00’ H: 4.58’
Footprint per unit	30.3 sq ft	152 sq ft	46.0 sq ft	160 sq ft
Storage Capacity per unit	45.9 cu ft	236 cu ft	109.9 cu ft	480 cu ft
Storage Capacity per square foot	1.5 cu ft	1.6 cu ft	2.4 cu ft	3.0 cu ft
Installed Storage Capacity per unit including stone base and cover	74.9 cu ft	341 cu ft	178.9 cu ft	642 cu ft
Installed Storage Capacity per square foot including stone base and cover	2.5 cu ft	2.2 cu ft	3.9 cu ft	4.0 cu ft
INSTALLED STORAGE CAPACITY per linear foot including stone base and cover	10.5 cu ft	42.6 cu ft	24.9 cu ft	24.9 cu ft

CREATE UP TO 25,000 CUBIC FEET OF WATER STORAGE
IN A SINGLE DAY WITH THE TERRE ARCH™ SYSTEM

Title	PDF
Terre Arch™ TA48 Arch Details	TA48 Arch Details (2024)
Terre Arch™ TA48 Distribution Manifold Details	TA48 Distribution Manifold (2022)
Terre Arch™ TA48 System Components	TA48 System Components (2024)
Terre Arch™ TA48 Sample Project	TA48 Sample Project
Terre Arch™ TA26 Arch Details	TA26 Arch Details (2024)
Terre Arch™ TA26 Distribution Manifold Details	TA26 Distribution Manifold (2022)
Terre Arch™ TA26 System Components	TA26 System Components (2024)
Terre Arch™ TA26 Sample Project	TA26 Sample Project

Title	File
Terre Arch™ 26 Plan Notes	Plan Notes Terre Arch 26
Terre Arch™ 48 Plan Notes	Plan Notes Terre Arch 48

Frequently Asked Questions

How does the cost of a Terre Arch™ compare to the plastic, HDPE or CMP products?

The important cost is the “Installed Cost of Void Space Underground”; precast concrete as a material cost, may cost more than plastic, HDPE or CMP; but the installed cost is the critical issue.

Terre Hill’s “just in time” delivery reduces material handling allowing each Terre Arch™ to be installed every 5 minutes; HS-20 load rating allows direct access for all installation equipment; and reduced stone requirements results in reduced project time and reduced man hours, creating an installed cost per gallon or ft³ that is very cost competitive; in many cases less than the installed cost of plastic, HDPE or CMP products.

When the project requires prevailing wage rates, on-site labor costs are significant. Terre Arch™ reduces labor costs to a minimum.

How does the structural strength of the Terre Arch™ compare to plastic and HDPE products?

Terre Arch™ 4” thick precast concrete arch structural strength and elasticity modules far exceeds that of plastic or HDPE

Precast concrete has very low creep and relaxation compared to plastic or HDPE

No Subsidence or Collapse danger with precast concrete.

What are the dimensions/weight/capacities of the Terre Arch™ ?

Model	Structure	Arch Height	Arch Span	Storage	Load Rating	Weight
Terre Arch 26	34″x8’x20″	26″h (internal)	52″w (internal)	338.62ft3 2.23ft3/ft2	HS-25	13,500 lbs</td
Terre Arch 48	55″x8’x20″	48″h (internal)	72″w (internal)	605.74ft3 3.78ft3/ft2	HS-25	15,700 lbs</td

What is the minimum soil bearing capacity required for a Terre Arch™?

Minimum soil bearing of 3000 psf; as verified by the Engineer, with a 12” stone base, is required to support the Terre Arch™. If cover on the Terre Arch™ exceeds 3’, the stone base may need to be increased to balance the bearing load with the bearing capacity.

What is the normal installation time for a Terre Arch™?

With a properly excavated and prepared base a Terre Arch™ can be set every 5 minutes; with installation of up to 30,000 ft³ in 1 day, including cover & backfill.

What is the design life of precast concrete?

100+ year usual life

What Warranty does Terre Hill Stormwater Systems provide?

4 Year Labor & Material Warranty

PROJECT PROFILE: View a Terre Arch Installation

NO BETTER SOLUTION

Calculate and compare the total cost-per-cubic-foot of storage for both materials and installation labor of your stormwater detention system, and you’ll see for yourself that the Terre Arch™ is a cost-competitive alternative to any plastic or corrugated metal product in the marketplace.

When you install a Terre Arch™ system, you’ll have the peace of mind knowing that its precast concrete design will outlast any other product or material in use today.

Use our Online Project Calculator to see if the
Terre Arch™ System will work for your next project.

Contact us today to discuss your project and learn why we offer the best products for your stormwater management needs!

Terre Hill Concrete Products is proud to partner with YQS: Your Quality Solutions as a preferred installer and maintenance provider for our Stormwater products.