One of the factors to consider during the purchase of rainwater tanks is the exact amount of rain that falls in your area in a certain time period. How is that computed? Read on to learn more.
The first thing you need to know about rainfall measurement, as it is done by meteorologists, is that it’s measured in millimeters or inches. This is usually followed by a certain time period. As such, a reading usually is something to the effect of: xx inches in the last 24 hours. However, a reading can go like this: xx inches in the storm, but, of course, this is only the case if there is indeed a storm in the area.
So what is the meaning of xx inches of rain in a certain time period? If the fallen raindrops stay where they land and do not run off somewhere else (like in a river or stream) or do not get absorbed into the soil, then an inch of rain, for example, should cover the ground with water an inch deep. But because this is not possible in reality, the said effect needs to be simulated with a device known as a rain gauge.
How Does a Rain Gauge Work?
A rain gauge isn’t a complex tool to make. In fact, even a middle-schooler can make one. All that’s needed are a standard can and a marker.
Once you have these materials, make marks on the can following standard measurements. Let the marks dry so it’s ready to measure rainfall. Set outside so it will measure rain from the first drops.
Reading the Gauge
Reading the gauge is as simple as checking the mark where the water ends. If the water ends at the three-inch mark, then that’s the amount of rain that has fallen in that period. Of course, when checking for the amount of rain that has fallen, keep a certain time frame in mind (i.e. 15 minutes, one hour, and other possible options).
Can Size Concerns
Does the can diameter actually matter? No. The height of rainwater collected in the can is equivalent to volume of water inside the can divided by the opening area. Plus the water that’s in the can has a volume proportionate to rainfall rate multiplied by the can area. Put together, the can area negates from the bottom and top of the ratio—implying that the area really doesn’t matter.
A More Accurate Gauge
If you’re looking for a more accurate rain gauge, go for the funnel-shaped standard collector instead of the one made from an ordinary can. The mouth of the funnel can gather many raindrops, and the narrower tube near the bottom allows even a small bit of rain to significantly change the water’s height.
That said, it follows that with this type of collector, an inch of water that’s in the gauge does not mean that an inch of rain has fallen. Instead of reading the water level the same way you would with the tin can rain gauge mentioned above, read the markings on the sides of the device.
Implications of Data Gathered
Make measuring rain in your area a habit and you should be able to eventually determine if you should go for slimline rainwater tanks or other options available. This habit can also help you determine if you should just get one tank or if two or more tanks are better for your household.