A local farmer, rancher, and apiarist, whose name you likely know, referred me to a pretty smart ranching friend of his who has been researching more cost effective flow measurement and data collection schemes. This retired aircraft engineer has found data collection devices with installed costs in the $500 – $600 range, instead of $1,200 up to $20,000. I’ll publish their names if they agree later; they should have a chance to read this before they put their names on it.
They aim to save themselves and all of you some of your hard-earned money. I really want
to see what data collection setups are available, hopefully this week there will be an all-in-one system that meets State requirements and is not such a budget-buster. There are also be some pre-fabricated flow measurement devices that can be easily dropped in a flat ditch where a weir (the least expensive device) won’t work, saving money compared to a formed-up flume.
From my years at DWR, my coworkers and I dealt with the trade-off between high accuracy and durability, at a high cost, and reasonable accuracy and lower durability for less money. This was always the tension, whether acquiring surveying equipment, portable flow measurement devices, or flow gaging components like data collectors, bubbler pressure sensors, or GOES satellite radios.
You have probably seen this triangle before – it is useful for planning prrojects. For the purposes of evaluating data collectors at diversions, Time is the owner’s, contractor’s, or engineer’s level of effort to make a diversion comply with the law. Scope is meeting the Water Board requirements – the length of that side cannot change. Everyone, including me, wants to reduce the Cost side of the triangle. Reducing Time means getting the labor, equipment rental, engineer’s report, and certification done cheaper – it’s the other way to reduce cost.
What is the effect of reducing cost? The size of the triangle equals quality, and that goes down. How much loss of quality is acceptable? In the case of data collectors, quality equates with the durability – maybe the device will only last 2 years instead of 4, or maybe it is twice as likely to quit working in the middle of an irrigation season. If quality goes down too much, then the data collection scheme will not meet Water Board requirements.
On the other hand, computer technology and sensors have improved over the years. Computing costs a tiny fraction of what it once did. Sensors have come down in cost a little, while their quality has improved somewhat. Maybe we can get just-fine data collection at half the cost – we’ll see!
