It's a Downhill "Climb": The Force of Gravity
- Friends of Bachman Lake
- 5 hours ago
- 2 min read
by Bruce Schroeder, Friends of Bachman Lake
There is no irrigation system in the Bachman Greenbelt. In order to put the green back in Greenbelt, at the end of 2024 we at Friends of Bachman Lake rigged up a Ram pump to pull water from a side creek in order to fill a tank. From there we ran hoses to the new plants we had purchased. With weather doing weather things, the side creek ran dry late last summer and manning those hoses to water manually was a workout! The good news is that about 80% of those plants have survived but it was clear that a new solution was needed.
Fast forward to this year and a request from AT&T to do a planting in the Greenbelt. We happily ordered the plant plugs, 1800 of them, and then were left pondering how we were going to water, especially when we were later told they had to be watered daily that first month!
Our in-house volunteer engineer literally cringed when it was suggested that we use a cart and watering cans. Then, the engineering mind went to work on an irrigation solution that would make gravity do the heavy lifting, so to speak. Going downhill from this point was actually a good thing!
"Gravity feed" refers to using gravity to create water pressure. This principle is at play in all kinds of water-based applications, from routing water off of your roof into a gutter, to moving water long distances through canals. It is also applicable to drip systems, but there is a complication: most drip systems require a minimum amount of pressure (typically 7-10 psi) to operate properly. Since gravity is a weak force, we would need a large container that is at least 16 feet above the drip system to achieve the required pressure to operate a traditional drip system. To get around the pressure/elevation limitation, we decided to drill small holes in the drip line greatly reducing the minimum pressure requirement.
In late spring, the design was refined, we bought the supplies, drilled holes in 3000 feet of drip line and completed the installation with the help of some talented St. Mark's Scouts. Although there were theoretical extrapolations in the drip line calculations, the design worked and this is going to be huge in terms of turning the conservation dial for the Greenbelt.
Why is this so important? Irrigation has been one of our most intractable issues. Installing water mains in the Greenbelt would cost hundreds of thousands of dollars. This moveable, reusable design will allow us to start adding Texas Native plants in the meadow over the next couple of years without a major investment. It is also a design that can be shared with other non-profits for their conservation work.
