- Author: Kat Kerlin, UC Davis
Reducing leaks a cost-effective way to save urban water without draining utilities
Before a drop of treated water in California ever reaches a consumer's faucet, about 8% of it has already been wasted due to leaks in the delivery system. Nationally, the waste is even higher, at 17%. This represents an untapped opportunity for water savings, according to a study from the University of California, Davis.
The study, published in the journal Environmental Research Letters, is the first large-scale assessment of utility-level water loss in the United States. It found that leak reduction by utilities can be the most cost-effective tool in an urban water manager's toolkit, provided utility-specific approaches are used.
“When I first heard about ‘leaks' I thought it sounded boring, but leaks are a huge component of our water systems and have a larger opportunity than many other water-saving methods to make an impact,” said lead author Amanda Rupiper, a postdoctoral scholar with the UC Davis Center for Water-Energy Efficiency. “As the first state to regulate its water losses, a lot of eyes are watching California, and this is an opportunity to impact policy here and elsewhere.”
Amid a multiyear drought, the passage of Senate Bill 555 in 2015 made California the first in the nation and among the first in the world to require water utilities to regulate their water losses.
Be specific
Using data from more than 800 utilities across California, Georgia, Tennessee and Texas, the authors characterized water losses across the country. They developed a model to assess the economically efficient level of losses, and used that model to compare various water loss regulations and modeling approaches.
The study found that one-size-fits-all approaches to leak management are not effective, economical or equitable for utilities, which vary in size and resources. Uniform approaches could lead to the mismanagement of urban water losses. However, applying utility-specific performance standards can deliver a similar amount of water savings at a profit for both utilities and society.
“Regulations that impose a uniform standard across all utilities will result in water reductions that are too stringent in some cases, too relaxed in others, and too costly overall,” the paper concludes.
Saving drips without draining utilities
Ideally, no leaks would occur in a system. However, while some leaks are obvious and accessible, others can be harder and more cost-prohibitive for some utilities to find and repair. The authors' model assessed when utilities could save the most water for their dollar to find and fix leaks in the system.
They found that for the median utility, it is economically efficient to reduce water losses by 34.7%, or 100 acre-feet per year. The median cost of water savings from leak management is $277 per acre-foot — cheaper than most traditional water management tools, including conservation campaigns and rebate programs.
“It's cost-competitive to do this and should be part of the profile of how we manage our water,” Rupiper said. “We tend to think of leaks as being a little drip, but leaks are not inconsequential. Drips add up to big flows, and we can't ignore them anymore.”
The study's co-authors include Frank Loge, Joakim Weill and Katrina Jessoe of UC Davis, and Ellen Bruno of UC Berkeley.
/h3>/h3>/h2>- Author: Wendy Powers
The first month of 2019 is just about behind us. I find that hard to believe! However, this weekend the increasing day length was both apparent and welcomed. Admittedly, I miss the long summer days of Michigan. Even a seemingly small 4° difference in latitude makes a big difference.
Last week I had a chance to listen to a reader-recommended TED talk that focused on improving work efficiencies. The speaker, Martin Danoesastro, makes the case that alignment around purpose enables autonomy and that autonomy allows for a faster, and more flexible work environment. Companies that organize themselves around multidisciplinary teams, as opposed to disciplinary silos, can be successful provided each employee is willing to be a leader. The hurdle is that each has to change their behavior and in so doing be willing to give something up. Thanks for the recommendation – I found the talk useful and timely.
Tomorrow is a UC ANR Town Hall to talk about UC Path, a new business system designed to change the way our operations data flows and integrates. The network of personnel working on UC Path are testing systems day and night right now to ensure that everyone receives a paycheck on April 1, 2019, and minimize disruptions. Long term, UC Path will improve efficiencies but it will take a change for that to happen and, no doubt, some things will be lost including mailed paychecks. As someone who still hasn't established a bank account with a financial institution that has a presence in California, I can't imagine getting a paper paycheck; it would parallel installing a landline telephone (something I stopped around 2001). Cybersecurity concerns contribute to changes, too. As a result, DUO multifactor authentication goes into effect soon. I can say that while this may change the way we work in that we have an added layer of sign-in to complete online approvals, I much prefer this system to the one we used at Michigan State. The Michigan State MFA required that you had to receive a 6-digit code by phone or text and enter that code to complete the sign-in.
I heard much discussion over the weekend about the need to change how we harvest crops. First, I read a post shared with my by Jose Aguiar: https://www.msn.com/en-us/news/us/could-california-produce-soon-cost-you-more-farms-face-labor-shortages-immigration-woes/ar-BBSNijI?ocid=ob-fb-enus-280&fbclid=IwAR3IuTVX_W3yONXcXsAq-Azk6jE-NoDrL9ukPnz4Gn5D7_5vz0zy2iml23Y. I am not sure if Jose was aware that the same topic would make its way to a news report over the weekend, but the reporter talked about this very topic of the increased cost of food because of labor shortages.
Imagine if we could find a way to harvest, mechanically, more of the fruits and vegetables grown? Harvest automation was one of the ‘gaps' identified by growers we met with in Blythe a couple of weeks back. The farmers thought UC and UC ANR should direct more effort to automation as a key step in maintaining California's stature in food production. The topic did not make its way into the 46 positions considered during the recent process, but I do wonder if we have enough FTE directed towards this problem at present. Sure, we would give up something in the process, but overall, the opportunity to change how the work is done would be worthwhile. Perhaps the alignment around purpose is not quite there yet.
- Author: Mark Bolda
Just started reading the book Machine Platform Crowd which is about the second phase of this machine age.
Great read, but what is striking is the summary of electrification and its initial slow uptake in factories. Why did something so obviously superior to coal fired steam power not get adopted the instant it was introduced?
There were actually a number of reasons. The adoption of electricity in factories was impeded by manufacturers who were reluctant leave to behind what they already were familiar with and knew well, and at the time electricity was only a marginally superior to coal anyway.
The real gains from electrification were to be made only when some manufacturers stopped just replacing steam engines with electric motors and redesigned the entire system - by placing electric motors on the conveyor belts, assembly lines and overhead cranes - and took full advantage of the new technology. The full potential of electricity now realized brought to bear huge advantages in price of production and flexibility, saturating the market with goods and hammering less able competition into the ground.
A lucid reading of the above should make us realize in the berry industry that in fact we are in a similar dilemma with our fitful advance on integrating automation into our agriculture. Really profitable automation simply doesn't mean replacing people with machines in the same fields as before. If we learn our lesson well from the transition to electricity from steam, we probably have to look at changing a lot about the production system itself.
- Author: Ben Faber
A recent grower survey in Santa Barbara County asked a whole bunch of questions. One of which was had they had an evaluation of irrigation distribution uniformity. This is a free service that can significantly improve on-farm water use and most importantly improve plant health. Avocados that don't get the right amount of water at the right time are extremely susceptible to root rot. Proper irrigation is the first line of defense against root rot, good farming that results in good economic returns to the grower.
So, with a free DU available to growers, how many do you think took advantage of the service? Barely 50%!!!!!!!! This just does not make sense. In a land of little water and frequent examples of what can happen with no water ………………..and high priced water, what is going on?
The local Resource Conservation District has done many system evaluations, and most results find that improvements can be made in distribution uniformity. This is true in relatively new irrigation installations. It does not take long for problems to occur in even well designed and installed systems.
During the summer of 2007, the Casitas Municipal Water District (CMWD) contracted with the Irrigation Training and Research Center (ITRC) of California Polytechnic State University, San Luis Obispo, to conduct field evaluations of drip/micro systems. A team of two students conducted 35 field evaluations.
Distribution Uniformity (DU) – DU is a measure of the uniformity of water application to trees throughout an orchard, with DU = 1.0 being perfect. The measured orchard DUs in the Santa Barbara/Ventura area had an average DU of 0.66, while the California state average for drip/micro is 0.85.
In general, there were substantial opportunities to improve the distribution uniformity (DU) of the water to trees throughout an orchard. An improved DU will minimize over-irrigation in some areas, and reduce under-irrigation in others. Key recommendations that were provided included:
Install a pressure regulator at the head of every hose
With a regular microsprinkler, doubling the pressure causes about 40 percent more water to come out of the nozzle. Pressure regulators are added to have similar pressures throughout the orchard and thus reduce the risk of over-irrigating portions of the field. On many farms, the difference between the highest pressures was double or even triple the lowest pressures (40-70% more water). By adding the correct high-quality, pre-set pressure regulators with the correct flow rate rating, the farmer can get similar pressures to every nozzle and prevent over-irrigation.
For a pressure regulator (PR) to work, more pressure must enter the PR than what the PR is rated for. For example, to use a 25 psi PR, you need at least 27 psi into the PR. All a PR does is reduce pressure; it cannot add pressure.
Another problem on hillsides is that some pipes have as much as 100 psi before the PR. A PR can effectively reduce the pressure down to 50%. What is recommended in these fields is to reduce the pressure in the pipe by adding an in-line valve halfway down the hill and throttling it down to a reasonable pressure.
Completely replace all microsprinkers with pressure compensating microsprinklers
Pressure compensating microsprinklers have an internal flexible diaphragm that reduces a pathway as the pressure increases. These allow similar amounts of water to get the trees even if the hoses do not have the same pressures. Whenever the pressure is doubled, 10 percent more water will come out of these emitters, compared to 40 percent more water with a regular microsprinkler. Having pressure compensating emitters can drastically improve the DU in virtually every avocado orchard because most irrigation systems were not properly designed for microsprinkler systems, or because the farmer has altered the original design by adding different-sized nozzles.
Reduce plugging problems
Major plugging problems are found in all orchards that did not have good filtration, even those that get district water. There were also some “within-system” causes of plugging. Almost all plugging is from simple dirt or rust, as opposed to bacteria or algae. Recommendations are as follows:
- Always have a filter at the head of the system. The required mesh size depends on the microsprinkler flow rate, but 120 mesh is a starting point.
- Remove hose screen washers that are found at the head of hoses, and replace them with regular washers (after installing a filter at the head of the system). The hose screen washers often plug up and cause the hoses to have unequal inlet pressures.
- Be sure to thoroughly flush hoses after any hose breaks.
- Double check the type of fertilizer that is being injected, especially any “organic fertilizers”. Some of these can plug emitters. In any case, inject the fertilizers upstream of the filters. If the filter plugs up, it is better to have discovered the problem early.
- Clean the filters frequently. Install pressure gauges upstream and downstream. When the pressure differential (as compared to a clean screen) increases by 3-5 psi, it's time to clean the screen.
In some orchards, there is a big plugging problem caused by insects crawling into emitters after the water is shut off. Many of the new microsprinkler designs utilize a self-closing mechanism to prevent insects from coming into the nozzle.
We have gotten a reprieve with the rains and refilled reservoirs, but it is ever more important to make sure our irrigation systems are doing what they are supposed to be doing. Call your local Resource Conservation District and get information about a system evaluation. Contact numbers can be found at: http://www.carcd.org/rcd_directory0.aspx
- Author: Ben Faber
At a recent CA Avocado Society meeting there was a discussion about bout flowmeters and their selection. Flowmeters measure the volume of water moving through a full-flowing closed pipe and as such are one of the key components of an irrigation system whether drip, microsprinkler or full pressure systems. They are essential for managing irrigation efficiently and for monitoring the performance of the irrigation system. Managing irrigation efficiently requires: (1) knowing how much water the crop has used since the last irrigation (irrigation schedu7ling); and (2) operating the irrigation system to apply only the amount of water desired. A flowmeter gives the grower the information needed to apply only the amount of water required.
A critically overlooked benefit of a flowmeter is that it makes it possible to identify changes in flowrate during the season (measured at the same pressure), which may indicate problems such as clogging of emitters or filters, leaks in the system or problems with the pump or well.
There are several types of flowmeters and each has their pluses and minuses. Propeller meters are the most commonly used, but can pose two potential difficulties: debris in the water and a small loss of pressure which can be a problem with low flow systems. Alternatives are magnetic meters, ultrasonic, turbine and venture meters. Proper selection is based on pipe size, range of flow and pressure loss. But as with everything it depends on proper installation and maintenance.
Attached is a nice little overview by Larry Schwankl on how to choose a flowmeter for your situation.
flow meters