Johnnie St. Vrain: What Are Small Red Barns and Boxes Along Water Ditches and Streams?

April 7, 2019

Dear Johnnie: I noticed a small box, painted red like a barn, along an irrigation ditch on the west side of Pella Crossing west of Longmont. I have seen others near water ditches. What are these?

Thank-you, Ditching School

Dear Ditching: Fantastic question, because it turns out there is a fascinating answer.

The boxes you are noticing along these water diversion ditches, and perhaps even along natural streams like the St. Vrain or Left Hand creeks, are there keeping a roof over equipment for measuring the flow of water in each channel.

They help state water officials and ditch company owners who rely on irrigation for supply to track flow data with live measurements, Sean Cronin, executive director of the St. Vrain Left Hand Water Conservancy District, told me.

“Each barn has a solar panel that powers a cellular signal to provide real time flow data to the ditch owners and the state of Colorado,” Cronin said. “As to why they are made to look like red barns, I think it is so they are easily identifiable, as proven with this inquiry.”

He also connected me with Shera Sumerford, water commissioner for the St. Vrain and Left Hand creeks with the state Division of Water Resources, and she explained some of the history of how flow rates have been recorded by ditch users and government to document who gets each valuable drop in our semi-arid climate.

“The state has been recording and publishing flow rates under Colorado Water Law as far back as 1901, such as the Oligarchy Ditch off of the St. Vrain Creek and the Haldi Ditch off of Left Hand Creek,” Sumerford said. “As technology has grown, the recording devices have as well: flow records have progressed from weekly hand-written recordings to paper chart recordings to now computerized data loggers.”

She added that water users have come up with their own ways to protect the data logging tech from inclement weather, and the boxes painted like red barns are just one design among various housing strategies.

“The data loggers work by a pulley system and those data loggers are then calculated to measure through a structure such as a Parshall flume or weir,” Sumerford said.

A Parshall flume is an open flow metering device that was made to measure the flow of surface waters and irrigation flows, and a weir is a similar device.

“State employees, ditch employees and also third-party users open these boxes up daily to ensure the accuracy of the recordings,” Sumerford said. “Ditch companies are required to have recording devices, not any brand specific but digital recording devices are preferred and at no cost to the state.”

In case you’re wondering, the recording devices cost about $1,820 each, Cronin said, as the Left Hand Ditch Company in 2018 installed recording devices and other equipment on 12 ditches over the year for a total cost of $21,842 — Cronin’s organization agreed to contribute $5,000 toward the ditch company’s devices.

Their cost is partly why they’re kept in the barns for shelter, I would assume.

You can look at the flows measured in the St. Vrain Creek watershed within the South Platte River Basin — by the devices you have been seeing around here — at this web address: bit.ly/2G2qvkz . Data for streams across the state can be accessed at that web page, too.

Send questions to johnnie@times-call.com .