Month: November 2024

My Ditch Is Too Flat / Too Shallow To Measure With a Weir

The simplest measurement device to install is a weir. Vertical side walls with board slots, or channel iron bolted onto the concrete, hold 2″ x 4″ boards. The boards need to be stacked 12″ to 18″ high, and the channel depth needs to be 24″ or deeper. Here is a 3′ wide weir with a 12″ board height:

But, what if the ditch is less than 24″ deep? The ditch shown below is about 18″ deep, and it must convey flow that comes near to the top of its banks. The ditch here is about 10′ wide and is passing 20 cfs:

The solution was to install a Watchman Replogle flume that is nearly as wide as the ditch – 8′ wide. It is installed on a concrete base so it stays level and does not tip. The flume floor is 3″ above the bottom of the ditch, and the maximum depth upstream of the ramp is 15″. In other words, the top of the flume as the same elevation as the top of the bank:

The flume is conveying about 12 cfs in these photos. It does so with a total accuracy better than +/- 10%.

The maximum ditch flow is 30 cfs. Will the flume convey that maximum flow, without overtopping? The photo below shows the flume conveying a flow of 30 cfs. Yes, it still measures flow accurately, without overtopping.

Here is the same size of flume in a different location, at a lower flow. Even with the low flow, the depth of water is the same all the way across the flume:

Here is another version of the same flume. The ditch here has plenty of depth, so overtopping was never an issue. So, why is a low-head flume installed here? This ditch is very flat and there is a possibility of restricting the flow into the ditch as it enters from a low pipe. Measuring the flow this way ensures accurate measurement without flooding the incoming pipe:

Write It Down (Or Possibly Lose A Water Right)

I got a call from a distraught diverter.  “My grandfather has irrigated this land since at least 1910, from _______ Creek.  Everyone knew about it at the time, we get 1.2 cubic feet per second for 105 acres of pasture up here.  Nobody was worried about filing on water rights back then, so we didn’t file at the Water Board until a few years ago.  But a new guy moved in next door and he says we don’t have a water right, it’s all his water.  We do have a well but we don’t use it until late in the season when the creek flow drops way down.  The neighbor claims we only use the well and never use the water from the creek.  Then he went and filed a complaint with the Water Board saying we never used water, which is a lie.  We got some letters from the state, we figured they were just the regular reminders and we were really busy.  It turns out one of the letters said the Water Board wanted to come to the ranch and see if we really divert water.  Now we have a letter that says we have to ‘cease and desist’ within 30 days or pay $500 per day fines!  What can we do about this?”

I asked, “Did your grandfather, parents, or you write down notes when you were irrigating?  Do you have photos at the diversion showing you were taking water?  Did you measure the flow somehow?”

“No, we don’t have anything like that.  But everyone around here used to know who used the water!  It wasn’t a problem until there were new owners.”

Have you heard the saying, “Write it down, or it never happened.”?  That is true in everything – conversations, phone calls, purchases, 

From one legal website, here is a list:

What Types of Contracts are Required to be in Writing?   Contracts that are for the transfer or sale of land, are for the sale of goods over $500, cannot be fully completed within one year of signing (according to the contracts terms), are related to marriage, involve a promise to pay another person’s debt (“surety contracts”), or will continue beyond the lifetime of a party performing the contract.

Water rights definitely belong on the list!

When I was a bureaucrat, I learned early on to document the work I was doing, document processes so I and others could do some technical process faster next time, and document all important conversations.  When email came around, I learned to email things to myself to have a record.  Then, 5 or 10 years later when questions came up, I had a dated electronic document to answer with.

So what happened with that diverter who called?  The diverter called the Water Board staffer who wrote the letter and arranged a visit to the property.  I went out and took photos, measured the diversion, put in a temporary measurement device, and wrote a report detailing all that the diverter told me.  Two Water Board engineers visited and wrote up a report.  Then nothing happened for three years.  The diverter is still using water from the creek, and now is measuring the amount of water and reporting it every year.  Hopefully the state won’t take any further action, but we don’t know.

The lesson is, keep records!  Even if something happened 100 years ago, write down now what you know about your water right, the diversion rate, the acreage irrigated, number of livestock.  When a complaint comes, it’s a lot easier to refute when you can just hand over a written account.