Atlantic Seaboard Fall Line

Atlantic Seaboard Fall Line

Atlantic Seaboard Fall Line

09/08/25

“What marks the end of the eastern coastal plain in the U.S.?”

The US Eastern Seaboard from New York City down to Georgia is dominated by the Atlantic coastal plain. The Atlantic Seaboard Fall Line escarpment marks the border between the coastal plain and the foothills of Appalachia. Around this border are some of the most populous cities in the Eastern US, such as Philadelphia, Washington DC, and Richmond. Rivers going through this fall line usually develop rapids or waterfalls when they reach the border, making cross-border navigation difficult. Many cities were settled along the Atlantic Seaboard fall line because they could trade with cities above and below the rapid descent of their rivers.

Soil Compression Index

Soil Compression Index

Soil Compression Index

09/07/25

“How can we measure the compressibility of fine-grained soils to effective stress?”

When soil is drained of water and air, the particles will close together and consolidate, increasing effective stress. The Soil Compressive Index measures the ratio of the change in void ratio to the change in effective vertical stress. The equation solid compression index = change in void ratio/log_10(final effective vertical stress/initial effective vertical stress), or C_c = delta_e/(log_10(sigma_2’/sigma_1’)), governs the solid compression index. 

Adsorption

Adsorption

Adsorption

09/06/25

“How can fluid molecules stick to the surfaces of objects?”

Fluid molecules can separate from the main “body”. For some molecules, they might stick to the surface of a solid or liquid through a process called Adsorption. Adsorped molecules usually create a film on the surface they stick to. Examples of adsorption include activated carbon in water filters that take contaminants, charcoal that removes odors in a fridge, and filters in gas masks. 

Aquifer Storativity

Aquifer Storativity

Aquifer Storativity

09/05/25

“How can we quantify the volume of water an aquifer is likely to release when there’s a change in head pressure?”

Wells pull water up from aquifers through pressure head reduction. But every aquifer is different, and we need to quantify how much water a formation is likely to release per pressure head reduction. Luckily, we have a parameter called Aquifer Storativity that measures the amount of water released per area to a given change in pressure head. For confined aquifers, storativity is equal to the specific storage times the aquifer thickness.

Aquifer Transmissivity

Aquifer Transmissivity

Aquifer Transmissivity

09/04/25

“How can we quantify the transmissive capabilities of an aquifer system?”

When water is pumped out of an aquifer, the aquifer’s properties will determine how fast and how much water will come to the well pump. The rate at which an aquifer can horizontally transmit water is called Aquifer Transmissivity. Aquifer transmissivity is measured in area per time unit, proportional to the product of the aquifer’s hydraulic conductivity and saturated thickness.

Aquifer Drawdown

Aquifer Drawdown

Aquifer Drawdown

09/03/25

“What happens to an aquifer’s pressure head when a well is inserted?”

Inserting objects into an aquifer will change its properties. When a well is inserted, the groundwater’s hydraulic head is reduced. The closer a piece of groundwater is to the well, the more it is reduced. This decrease in pressure is known as Aquifer Drawdown. Aquifer drawdown is important for completing aquifer water production field tests.

Rock Folds

Rock Folds

Rock Folds

09/02/25

“Why are some rock layers folded into themselves?”

Rocks undergo all sorts of deformations throughout their lifetimes. Rock layers may fold into themselves when they’re compressed and form Rock Folds, or curved layers of rocks. Rock folds are more common deeper in the Earth’s crust, where hotter temperatures and higher pressures make rock material more ductile. Rock folds made deep underground may surface to the Earth, creating beautiful geological marvels.

Image credit: https://newcreation.blog/

Spillways

Spillways

Spillways

09/01/25

“How can we release water from a dam when it’s too full?”

Dams and reservoirs hold a certain amount of water. When there’s too much water, it can damage the dam and the surrounding area. So what if we were to design a mechanism that allows us to release a certain amount of water before overflow occurs? Well, this is the idea behind Spillways. Spillways come in all shapes and sizes and are a fundamental part of many water containment infrastructure systems.

Trellis Drainage Patterns

Trellis Drainage Patterns

Trellis Drainage Patterns

08/31/25

“How do grid-like rivers form?”

Drainage pattern shapes form based on the local geology. Sometimes, the surface might have alternating bands of resistant and non-resistant rock. When water flows over these surfaces, the non-resistant rock erodes more steadily and turns into a valley between the resistant rock bands. The main tributaries of these rivers will run through these valleys and form perpendicular streams down the edges of the ridges of the resistant layers. These Trellis Drainage Patterns are prone to flooding because the water flowing through the valleys can overflow during heavy rains. Bakudabakek/Wekwabegituk (also named “The Bay of Fundy” by the settler-colonial state of Canada) is an example of a trellis drainage pattern.

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