A rain gauge might save a person money and time if they knew last nights’ storm delivered just the right amount of water to the lawn.

By Jeff Burbrink
Extension Educator, Purdue Extension Elkhart County

Jeff Burbrink
Extension Educator, Purdue University Elkhart County

GOSHEN — The first people known to collect rainfall data were the ancient Greeks and the people of India in 400 to 500 B.C. The concept was not much different than it is now: a simple tube, pointing skyward, with markings on the side to measure rainfall.

In 1441, King Sejong of Korea invented the first standardized rain gauges in which 10% of the rain “catch” represents the unit of rainfall being measured. In our case, a 1/10 inch catch in a simple rain gauge typically measures 1 inch, or a 1-millimeter catch would represent a centimeter of rainfall.

Sejong sent an official rain gauge to each village in Korea and assigned a villager to measure and record the catch. Using the data collected, the kingdom was able to better predict the amount of grain that would need to purchased or sold to help his countrymen survive the winter.

A few hundred years later, the basic concept of rain gauges remains the same, but there have been major innovations to make recording data easier. Automatic tipping buckets, which have mechanisms to both collect, measure and record data, make it possible to operate a gauge from a remote site, for instance. Apps can now transmit data via the internet to your phone from gauges miles away, and in turn, you might be able to control your irrigation system from that same phone.

What has always fascinated me is how much variation there is from one gauge to another, even those gauges within short proximity. I was once told, there is only a 60% correlation between gauges one mile apart in this part of Indiana. So, if you are comparing gauges that are two miles apart, the correlation is only 36% (60% of 60%). Just hearing people talk about their rainfall totals at the coffee shop and meetings, I am inclined to agree with that thinking.

It is very easy to observe these differences if you study online weather data from sources like CoCoRaHS, a group of volunteers who collect rainfall data. We have about 15 Elkhart County volunteers feeding rainfall data into that system daily. It’s not unusual to see 0.5 to 1-inch difference in gauge totals in June to August when pop up storms appear.

What this type of data brings home to me is that people who grow plants really should pay attention to the rainfall amounts. Certainly, farmers with irrigation systems scattered across the community need accurate rainfall data close to their fields to make good decisions. But even those people with gardens would find it useful to know if additional water is needed after a brief shower on a warm day.

And, as expensive as it can be to operate an irrigation system in a lawn, I would think that a $5 to $10 rain gauge might save a person money and time if they knew last nights’ storm delivered just the right amount of water to the lawn.