Building a Corrugated Culvert Cistern for Water Storage

Site Preparation

The first step in building a corrugated culvert cistern is to prepare the site. Begin by leveling the ground where you plan to install the cistern. This ensures that the base of the cistern will be level and stable. Once the ground is level, compact it to ensure it can support the weight of the cistern and any water it will hold. Next, build a 6×6-foot frame using 2×6 lumber. This frame will serve as a guide for digging the hole for the cistern. Dig the interior of the hole to achieve an 8-inch slab thickness. This thickness is crucial for providing a solid base for the culvert.

Slab Construction

After preparing the site and building the frame, it’s time to construct the slab. Before pouring the concrete, install PVC overflow and hose spigot pipes. These pipes will be used to manage water levels and access water from the cistern. Next, add rebar and concrete mesh to the slab. Use ¾-inch rebar for structural support and spacing. The rebar should be placed in a grid pattern with 12-inch spacing between each bar. This provides the necessary strength to support the weight of the culvert and water. To save on concrete and provide additional stability, add riprap rocks around the perimeter of the slab. Riprap rocks are large, irregularly shaped stones that help prevent erosion and provide a solid base for the slab.

Culvert Installation

Once the slab is complete, it’s time to install the culvert. Mix concrete to a ‘soupy’ consistency. This consistency allows the concrete to flow easily and fill any gaps between the culvert and the slab. Use a boom hoist to lower the culvert into the slab. If a boom hoist is not available, you can use fence pipes to manually lower the culvert. Ensure there is 4-5 inches of clearance between the culvert and the slab edges. This clearance allows for proper water flow and prevents the culvert from sitting directly on the slab.

Sealing

After the culvert is in place, it’s time to seal the tank. Apply two coats of Ames’ Blue Max Liquid Rubber to the tank interior and seams. This waterproofing material is essential for ensuring the cistern does not leak. Allow the first coat to dry completely before applying the second coat. This ensures a thorough seal and prevents water from seeping through any cracks or seams.

Final Assembly

The final step in building the cistern is to attach a spigot valve and position the overflow pipe. The spigot valve allows you to access water from the cistern. Position the overflow pipe below the tank’s maximum level to prevent water from spilling over the top. Finally, install a lid on the cistern. You can use a custom lid or build one yourself. A DIY lid can be made from plywood or another durable material. Ensure the lid fits securely on the culvert to prevent debris from entering the tank.

Common Mistakes

One common mistake when building a corrugated culvert cistern is not properly leveling the ground. A poorly leveled base can cause the cistern to settle unevenly, leading to cracks and leaks. Another mistake is not using enough rebar and concrete mesh. This can result in a weak slab that cannot support the weight of the culvert and water. Failing to properly seal the tank can also lead to leaks and water loss.

Practical Tips

To ensure the success of your project, consider the following tips. First, choose a location for the cistern that is level and free from potential water sources that could cause flooding. Second, use high-quality materials for the rebar and concrete mesh. This ensures the slab will be strong and durable. Finally, take your time when applying the waterproofing material. A thorough application is crucial for preventing leaks.

Getting Started

Building a corrugated culvert cistern is a cost-effective way to store water. The estimated cost for a new materials build is $300-400. The cistern can hold up to 1,100 gallons of water for an 8×5-foot culvert. This makes it a valuable asset for water storage in areas with limited access to water. With proper construction and maintenance, a corrugated culvert cistern can last for many years, providing a reliable source of water.