A rainwater harvesting discussion can quickly become a conversation about tank capacity. For building owners and consultants, there is an earlier question worth answering: where will the collected water actually go?
PUB identifies rainwater harvesting as an option for collecting water for non-potable use within a development. That creates an opportunity for reuse, but each project still needs a clear operational purpose.
Our view is that demand should shape the design conversation from the beginning.
Understand the use before choosing the capacity
Consider a development evaluating rainwater for landscape irrigation. The team should examine the planting requirements, irrigation schedule and how demand changes with weather. Those assumptions should then be considered alongside the available catchment, rainfall pattern and storage options.
For this assessment, annual rainfall and annual demand are useful starting figures. We would also ask how collection and consumption line up over time. The timing of each affects the storage decision.
This discussion should involve the people who will operate the system. They can help explain actual watering practices, site constraints and how settings may change after handover.
Agree on what success means
Before specifying equipment, we recommend agreeing on what the owner wants to measure.
Useful questions include:
How much harvested rainwater reaches the intended end uses?
When and why is supplementary water required?
What operating effort and cost will the system need?
These questions give the project team a basis for assessing performance after commissioning. They also help distinguish design assumptions from what is happening on site.
Design for a system that can be understood
Metering, accessible controls and clear operating instructions deserve attention early in the project. The owner should be able to understand how water moves through the system and investigate changes in performance.
At Netatech, our perspective is that a rainwater harvesting proposal should explain the relationship between collection, storage and use. That gives owners a stronger basis for choosing a system and managing it throughout its operating life.
Planning rainwater reuse for your development?
Talk to Netatech about aligning rainwater harvesting with your site’s water demand and operating needs.
