I’ve finished the next step implementing my rainwater collection and harvesting to supply my rain drip irrigation system. I made a few improvements in the rain harvesting collection system and expanded the piping system to run a water supply down to the raised bed garden. Previously, I had installed my own drip irrigation system when beginning my container garden. The raised bed garden is over 150 feet slightly downhill from the rainwater collection tank and I was concerned that it might have insufficient pressure to power the rain drip irrigation system. I also needed to allow for future expansion of my rainwater collection and harvesting system by connecting multiple rainwater collection tanks into a single, balanced system for harvesting rainwater. Lastly, after prototyping the rainwater collection and harvesting system supply line with a garden hose, I needed to allow for a more permanent solution with pipe buried under ground instead of a garden hose running 150 feet to my garden. I was successful in this stage. The rainwater collection and rain harvesting improvements to power my rain drip irrigation system were completed without a single issue.
Problems with the Rainwater Collection Wash Drain
The drainage method for the wash collection tube in the rainwater collection system was a simple hose bib. The hose bib was opened just slightly which allowed for the wash tube to drain easily after each rain. This worked fine when there were relatively heavy rains. I thought this might present a problem for slow gentle rain harvesting where the drain rate from the wash tube was faster than the collection rate and the wash tube never filled sufficiently to allow water to flow into the rainwater collection tank. This proved true
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A Simple Solution to the Rainwater Collection Wash Drain
I used the simplest solution I could think of to fix the problem – a simple drip irrigation timing unit to control the outflow from the rainwater collection wash tube. The timer is set to run for 5 minutes each Sunday evening. This allows rain harvesting water to build up from a slow rain during an entire week. I can’t imagine that there is enough build up of debris on the roof that would warrant draining the wash tube more frequently than once per week. I guess I could remember to drain it manually each week but I doubt that is a sustainable solution for harvesting rainwater. This drip irrigation system timer costs less than $30 and solve the problem of too much wash drainage from my rainwater collection system.
Initial Rainwater Collection Outflow
The preliminary outflow connection from my rainwater collection and rain harvesting system was a simple butterfly valve. This served it’s purpose nicely to contain the rain water and easily allow for future expansion. It also allows me to easily isolate this tank if problems occur in the future. I like lots of valves – they give me options!
Parts and Pieces for Rain Harvesting Flow Control
The outflow valve system from the rainwater collection and rain harvesting system to support both tapping it to supply the rain drip irrigation system and allow for future expansion turned out to be pretty simple. I extended the outflow with a T connector for a hose bib, a T connector for a permanent pipe and another end valve. The hose bib connection will power the initial rain drip irrigation prototype and allow for controlled drainage of any and all tanks in the future. The second T connector allows me to make the rainwater supply to the raised bed garden permanent once I’ve worked out the kinks. The final butterfly valve allows me to control the flow from this single tank but also allows me to isolate the rainwater supply to the rain drip irrigation system in the event that the tanks run dry from harvesting rainwater and water needs to be supplied from the city water system.
Flow Control Header for Harvesting Rainwater Installed
The final installation of the piping control system for the rainwater collection and harvesting system turned out to be simple and easy – both things that I I like. The valves on both ends of the piping control system allow for flow balance and isolation. The hose bib connection supports both a rain drip irrigation system prototype with a garden hose and allows me to either fill or drain the entire system from an external source. The additional T connector will be the head end of the permanent piping of the rain drip irrigation system at the raised bed garden.
Summary of Rainwater Collection and Rain Harvesting Improvements
The expansion of the rainwater collection and rain harvesting system for the rain drip irrigation system at the raised bed garden is complete. I’ve added a flow control valve to balance harvesting rainwater into the rainwater collection tanks, a hose bib connector for prototyping and additional inflow and outflow. I’ve also added a stub to make the rainwater collection and rain harvesting system supply of rain drip irrigation to the raised bed garden more permanent once the prototyping stage is completed