"Wisdom begins in wonder" – Socrates
Stagnation Pressure
08/12/25
“What happens when a moving fluid comes to a halt?”
Many fluids move with a certain speed. But if they’re forced to abruptly come to a halt, they’ll convert all of their kinetic energy into pressure. This Stagnation Pressure is vital for understanding how static and dynamic pressure relate to each other and fluid motion.
Hydraulic Head
08/11/25
“How can we conceptualize the total potential of a fluid’s pressure?”
We know that a fluid that is higher than another will usually flow downwards if they’re connected. However, if the lower fluid has a high enough pressure or velocity, then it can overpower the higher fluid and move upwards. One way to conceptualize this is to imagine that the pressure and kinetic energy of each fluid adds extra height, and whichever fluid has the highest theoretical “height” will govern the direction of flow. This is the concept behind Hydraulic Head, as illustrated by the equation h = P/(rho_w * g) + z + v^2/(2*g), where h is the hydraulic head, P the fluid pressure, rho_w the fluid density, g the gravitational constant, z the fluid elevation, and v the fluid velocity.
Stormwater Discharge
08/10/25
“What happens when stormwater runoff enters a regulated body?”
Stormwater runoff is the water from rain that flows over the ground instead of seeping into it. Some of this rain may enter a regulated body, such as a stream or a storm drain. This water, known as Stormwater Discharge, may contain pollutants it picked up during its journey on the surface. Infrastructure operators should treat stormwater or prevent it from getting polluted before it enters water bodies. Engineers and planners must design public facilities around predicted peak stormwater discharge values and holding times.
Unit Peak Discharge
08/09/25
“How can we get a base estimate of a small watershed’s discharge potential?”
Runoff events vary by storm and watershed. However, we may want to compare the discharge potential of different watersheds without having to account for variations in different storms. So, what if we were to calculate how much peak discharge each watershed would produce for a 1-inch rain event, regardless of its area? Well, this is the idea behind Unit Peak Discharge, which is measured in flow rate per area per runoff amount. Calculating unit peak discharge is essential in estimating peak discharge using the TR-55 graphical method.
TR-55
08/08/25
“How can we use simplified procedures to estimate runoff and peak discharges in small watersheds?”
Predicting runoff and peak discharges for watersheds can be a very difficult task. There are so many factors that you have to consider without great precision. However, for small watersheds in the US, the Natural Resources Conservation Service of the U.S. Department of Agriculture has developed a procedure called TR-55 to handle these. TR-55 uses empirically derived data and hydrological modeling to determine runoff and peak discharges.
Underdrains
08/07/25
“How can we use pipes to prevent the bottom of infrastructure from getting damaged?”
During flood events, whether it’s from groundwater or rainstorms, excess water can damage the foundations of infrastructure. One simple technique to address this is to use pipes to redirect water from the bottom of the infrastructure to elsewhere. These Underdrains are an incredible tool that gives infrastructure operators much more flexibility in designs. French drains are one example of underdrains.
Image credit: https://cshomeconstruction.com/
Runoff Reduction Volume
08/06/25
“How do we classify the amount of stormwater runoff that can be captured and kept out of the stormwater system?”
Rain brings stormwater runoff. And when stormwater runoff is too large to control, it can lead to damaging flooding and pollution. But suppose systems, natural or human-made, are designed clever enough. In that case, they can capture some of this stormwater and prevent it from entering stormwater handling infrastructure through absorption, infiltration, evaporation, or reuse. Whatever amount of stormwater is handled through this manner is classified as Runoff Reduction Volume. Interventions like rain gardens and bioswales can increase the expected runoff reduction volume.
Mountain Headwaters
08/05/25
“Where do mountain rivers originate?”
Mountain rivers are mighty bodies of water that cascade down heights to end up in larger bodies of water or deserts. But where do these rivers form? Well, clouds will commonly release water over mountain peaks. Some of this water will move downwards as surface runoff and will collect together to form a river. The source of this river is called Mountain Headwaters, and is a fundamental part of the Earth’s function..
Prism Storage (Hydrograph)
08/04/25
“How can we visualize the steady-state water storage of a stream?”
Water streams have a defined path that holds water. When operating under steady-state conditions, these streams will have a uniform profile that we can calculate for water storage known as Prism Storage. Prism storage is a fundamental idea in parts of environmental engineering and can help model numerous real-world situations.
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