We always hear about smart grid technologies for electricity but rarely hear any mention of using smart technology to improve our water systems. Our water systems need help. The American Society of Civil Engineers has given the country’s water systems a grade of D- for the last decade. It’s been estimated that as much as 50% of water is lost to leaks in some systems, with even good systems losing as much as 20% of water. Major cities in the US like San Diego, Las Vegas, and San Antonio have had water scares in the recent past. In the telecom industry, we talk about outdated copper networks built in the 1970s but there are major water arteries in many communities that go back to the Civil War. My city of Asheville, NC recently had a major water project to replace wooden water pipes used in the original water routes from the local reservoir.
The good news is that there are tools that can help to pinpoint the biggest problems in water systems. Just like an electric grid, the first step in developing a smart water system requires placing numerous sensors throughout a city to gather information on water flow and pressure. At the simplest level, once engineers understand the normal water flow in a system, then any deviations and drops in water pressure are an immediate signal that there is a new leak in the system.
A second step is to upgrade to more accurate water meters. Engineers have estimated that as many as 40% of the meters used to serve high-volume commercial customers under-report the amount of water being used, and consequently underbill for water usage. Old and inaccurate meters can also disguise leaks.
Once more accurate water meters are installed, it becomes possible to start identifying long-standing water leak problems. It’s possible to build computer models for small sections of a water system to be able to compare the amount of water entering a neighborhood compared to what is reaching meters. This allows a city to rank and compare neighborhoods and identify the parts of a city with the highest amount of wasted water. After that comes the effort needed to identify the location of leaks. Sensors and computer modeling can be applied to smaller sections of a neighborhood to better pinpoint leaks.
There are also new techniques being developed. Daniel Tartakowsky, a professor of energy resources at Stanford recently published a paper suggesting new techniques to specifically identify the location of leaks. Even after computer modeling has identified a street with a major leak, the cost of pinpointing a leak located under city streets can be costly. Nobody wants to dig up whole city blocks looking for wet soil.
The proposed technique uses an older concept known as a water hammer. This has been used for years and is done by quickly turning off water and using sensors to gather data about how the shock wave and vibrations from turning off water propagate through pipes. Such vibrations tend to stop or be altered when hitting damaged pipes. The traditional water hammer technique involved time-consuming and costly calculations. The new technique proposed by Dr. Tartakowsky uses a computer model that can be handled with a laptop that can interpret the results from a water hammer test quickly to pinpoint the location of a leak, often within ten meters.
All of this new technology benefits from a city that has ubiquitous broadband capabilities to closely and accurately monitor the the numerous sensors needed to establish a smart water system. This is something that is sorely needed. Cities everywhere worry about having high water rates, which can be driven by processing and providing a lot of clean water that is then wasted in leaks.