Underground water cisterns are essential for storing rainwater or other water sources, providing a reliable supply for irrigation, household use, and emergency situations. Constructing an underground cistern requires careful planning and execution to ensure durability and safety. This article covers the materials, construction methods, and considerations for building underground water cisterns.
Materials for Underground Cisterns
1. Reinforced Concrete: This is a popular choice for underground cisterns due to its strength and durability. Cast-in-place reinforced concrete is particularly effective for underground structures[3][6].
2. Fiberglass: Fiberglass cisterns are lightweight, corrosion-resistant, and versatile, making them suitable for commercial applications[2][4].
3. Polyethylene (PE) Plastic: Poly tanks are lightweight, cost-effective, and easy to install. They are commonly used for underground water storage[4][10].
4. Steel: Steel cisterns are strong and durable but require a protective coating to prevent corrosion[2][4].
Construction Steps for Underground Cisterns
1. Site Selection and Excavation: Choose a site with stable soil and minimal risk of flooding. Excavate a hole that is slightly larger than the cistern dimensions[7][9].
2. Base Preparation: Lay a firm, level concrete base to support the cistern. Ensure the base is designed to handle the weight of the tank and water[9].
3. Cistern Installation: Carefully lower the cistern into the excavation using lifting equipment. Ensure it is level and properly positioned[7][9].
4. Backfilling: Fill the space around the cistern with compacted material like pea shingle to prevent settling issues[9].
5. Access and Maintenance: Include a manhole or access point for maintenance and inspection. Seal the top to prevent contamination[3][9].
Considerations for Building Underground Cisterns
– Waterproofing: Ensure the cistern is fully waterproof to prevent leaks and contamination. Use materials like vinyl liners if necessary[8][10].
– Structural Integrity: The cistern must withstand soil pressure and water weight. Reinforcing materials like rebar are essential for concrete structures[1][3].
– Groundwater and Uplift Protection: If the groundwater table is high, secure the cistern to prevent uplift[10].
– Certification and Compliance: Ensure all materials and components meet standards for potable water use, such as NSF/ANSI Standard 61[6].
Conclusion
Building an underground water cistern is a significant project that requires careful planning and execution. By choosing the right materials and following proper construction techniques, homeowners and communities can create reliable water storage systems that support sustainable living and emergency preparedness. Whether using reinforced concrete, fiberglass, or polyethylene, each material offers unique advantages that can be tailored to specific needs and environments.
Read More
[1] https://www.dancingrabbit.org/building/how-to-build-a-rainwater-catchment-cistern/
[2] https://bygging-uddemann.com/2021/07/14/the-complete-guide-to-cistern-materials-2/
[3] https://extension.psu.edu/rainwater-cisterns-design-construction-and-treatment
[4] https://www.tank-depot.com/blog/underground-water-tanks-everything-you-need-to-know
[5] http://www.cuvewaters.net/fileadmin/edit/Downloads/RFWH_Toolkit/6_CM2_R-U-Tank_E.pdf
[6] https://www.gov.mb.ca/sd/pubs/water/drinking_water/water_factsheet_cisterns.pdf
[7] https://www.ntotank.com/blog/how-to-install-an-underground-water-tank
[8] https://www.bt-innovation.de/en/fields-of-application/waterproofing-a-cistern/
[9] https://www.waterbuttsdirect.co.uk/media/mageplaza/product_attachments/attachment_file/u/n/underground_water_tank_installation_guide.pdf
[10] https://www.ahfc.us/iceimages/manuals/building_manual_ap_4_water_cistern.pdf