By Josh Cosford, Contributing Editor
My wife and I love Ithaca, New York. It’s a great little college town in the Finger Lakes region of New York, where you can walk the steep Cascadilla Gorge Trail from downtown up to Cornell University. We actually had no idea Cornell was in Ithaca the first time we popped out into the Ivy League campus at the top of the trail, but we happily explored the campus, which was open on a Saturday. After poking around the Law School, we popped out onto College Avenue, where I was awestruck to come face to face with the DeFrees Hydraulics Lab.
Being the hydraulics aficionado that I am, I jumped at the chance to explore the building, and for the one or two of you Cornell alumni reading this, you know where this is headed. The DeFrees Hydraulics Labs educates America’s finest students on the other hydraulics, which I quickly discovered when poking my head into doors I shouldn’t.
Fluid mechanics and hydrology are the OGs of hydraulic technology, and are entirely different fields than fluid power. Water hydraulics, generally speaking, is the science describing water as it moves atop the Earth. Channels, aqueducts, and reservoirs are studied along with the interaction of drainage, conveyance and flooding prevention, just to name a few. (If you came here thinking you’d learn about water a hydraulic fluid medium, click here. Or, if you want to understand how hydraulic fracking uses water, click here.)
Ancient Roman aqueduct on Plaza del Azoguejo square in Segovia, Spain
We fluid power professionals know our industry is in its infancy compared to the thousands of years’ old technology developed to irrigate crops and provide fresh water to villages. The word hydraulics stems from the ancient Greek words for water and pipe. Etymology aside, hydraulics was used in Mesopotamia and Egypt a solid eight thousand years ago for crop irrigation and then eventually for ingenious inventions like the water clock.
Eventually, we figured out that water could contain energy, either dynamically through movement or potentially by mass. The first known watermills took advantage of the flowing water from streams and rivers to rotate milling stones to grind grains into flour. For centuries, watermills provided the primary mechanized production system outside of human and animal labor. So important were mill sites that villages sprang up around them to help with other purposes such as sawing wood, fulling textiles and pumping water.
Oftentimes, settlements were less conveniently located near water, so methods to transport and store water were created. The famous aqueducts of the Roman Empire still stand in various locations throughout Southern Europe, figure 1, some of which stretched for well over fifty miles. The Persians created underground aqueducts, and even today the 2700-year-old Gonabad Qanat in Iran is still active today.
Water hydraulics are widespread today in many advanced applications. Hydroelectric power stations provide sustainable energy for even large cities, and the scope of considerations goes beyond hydraulic head and flow capacity. The surrounding catchment area must be studied to ensure adequate upstream water availability, thought put into drought and flood management, and sediment and erosion impact must be analyzed.
The scope of water hydraulics is vast, and our beautiful blue planet provides both blessings and curses depending on where you live. Our ever-changing sociopolitical and environmental migration patterns will always provide hydraulic engineers with challenges to satisfy our need for water. If water hydraulics sounds like the field for you, I recommend you put Cornell University on your shortlist. You’ll receive a top-tier education while enjoying the unique geography of this hillside town. The only downside is having to tolerate middle-aged fluid power professionals poking their heads into your lab to look for power units.
Filed Under: Engineering Basics
