Rainwater Harvesting System: A Sustainable Solution
Water conservation has become a crucial issue globally, and the need for sustainable solutions is more important than ever. Rainwater harvesting systems effectively conserve water by collecting and storing rainwater for non-potable uses such as watering plants, flushing toilets, and washing clothes. In this article, we’ll explore how Elmid Design Inc., a professional engineering company, collaborated with CleanFlo Company, a contractor, and installation company, to design and install a residential rainwater collection system for a homeowner in Richmond Hill, Ontario, Canada.
Elmid Design Inc. and CleanFlo Company teamed up to provide water conservation solutions for the greater Toronto area. This particular project aimed to collect rainwater for water conservation purposes and comply with the city’s onsite stormwater management regulations.
Site Analysis and System Design
Before installing a rainwater harvesting system, it is essential to conduct a detailed site analysis to create an adequate design. Elmid Design Inc. and CleanFlo Company started the project by analyzing 55 years of location-specific rainfall data to determine the potential volume of rainwater that could be collected and used based on demand and tank size.
The companies used software to simulate rainfall events and generate a hydrologic model for the property, which helped them understand how the system would perform. After determining the actual usable rainwater, they could then calculate the return on investment. Tanks are the most costly item in a rainwater harvesting system, so determining the smallest tank size that will collect the most water based on the criteria described above significantly impacts the system’s total cost.
Another critical element in designing a rainwater harvesting system is the water demand. To determine the water demand, they used two methods:
- Historical records or meter readings that provide an accurate measurement of past water demand.
- Estimated future water demand based on usage type, number of occupants, and days used per week.
After the analysis, the system was projected to harvest 250 cubic meters of rainwater each year.
Elmid Design Inc. prepared a complete design set and a quote for a system costing approximately $12,500, which the client accepted. The system included:
- A 1,000-gallon water cistern
- Six 1-foot sections of manway for access to the buried tank
- A self-cleaning rainwater prefilter for a 4-inch PVC downpipe
- A 1.25-hp submersible on-demand water pump with float control in the rainwater cistern to supply the irrigation system
Installation and Performance
The installation took place in September 2017 over the course of four days. The process involved:
- Excavating the water cistern pit to a depth of 4 feet of ground cover
- Filling the pit with high-performance bedding, as specified by the tank manufacturer
- Installing downpipe outlets, piping, rainwater prefilter, and overflow, routing them to and from the water cistern
- Installing the tank manways and backfilling the tank appropriately
The installation did not experience any major problems, and the system has since performed as expected. The analysis predicted the system could harvest 250 cubic meters of usable rainwater annually. Of that volume, approximately 170 cubic meters would be lost in overflow events because the tank was already full. Supplying the household with approximately 80 cubic meters of rainwater per year at $3.6225 per cubic meter, with a 5% increase per year, would save the household approximately $289.80 in the first year and $890 on the payback year.
While the approximate payback period for this project was 22 years, the actual savings to the community and environment were undoubtedly larger, and the cost of water will likely rise in the coming years, possibly shortening the payback period significantly.
The Importance of Stormwater Management
As impermeable surfaces increase, cities enforce runoff bylaws, and water rates rise, homeowners need more efficient stormwater retention methods. A well-designed rainwater harvesting system can play a significant role in sustainable water management and stormwater retention.
Elmid Design Inc. specializes in developing comprehensive stormwater management plans for various projects. They offer services such as erosion and sediment control plans and site grading plans to ensure that projects meet regulatory requirements while promoting sustainable water use.
Key Takeaways
Rainwater harvesting systems offer several benefits, including:
- Reducing the demand for potable water by reusing collected rainwater for non-potable purposes
- Decreasing stormwater runoff and mitigating the risk of flooding
- Promoting water conservation and sustainability
Working with experienced companies like Elmid Design Inc. and CleanFlo Company ensures that your rainwater harvesting system is designed and installed to meet your specific needs and comply with local regulations.
In conclusion, rainwater harvesting systems are a valuable addition to any residential property, offering an eco-friendly solution for water conservation and stormwater management By implementing a well-designed system, homeowners can save on water costs while contributing to a more sustainable future.
