## Ballast Fouling in Railways

In this transportation/railway engineering blog post we discuss ballast fouling, a rail performance issue that each year costs millions of dollars for repair and maintenance in tracks all over the world.

## Drawdown in Aquifers: Theis and Hantush-Jacob Well Functions

In this hydraulics/hydrology/hydrogeology blog post, we discuss two simple models used to assess aquifer drawdown due to groundwater flow in confined and semiconfined wells.

## Harmful Algal Blooms and Lake Restoration

In this blog post, we discuss methods used in control of algal blooms and lake restoration. Methods discussed include sediment dredging and ultrasound.

## Saltwater Intrusion in Coastal Aquifers

In this hydrology/hydraulics blog post, we discuss aspects of saltwater intrusion in coastal aquifers – including use of the Ghyben-Herzberg relation, effect of sea-level rise, and more.

## Hoek-Brown Failure Criterion and Geological Strength Index

In this blog post, we discuss the Hoek-Brown failure criterion, a well-established approach to the mechanical strength and rock masses. Also included is a quick introduction to the Geological Strength Index (GSI).

## Four Models for One-Dimensional Infiltration of Water in Soils

In this agriculture blog post, we discuss four of the simplest models used to assess infiltration of water in soils: the Lewiis-Kostiakov equation, the Horton equation, the Green-Ampt equation, and the Philip equation.

## Estimating Runoff Volume with the SCS-CN Method

In this hydrology blog post, we introduce readers to the SCS Curve Number method of precipitation runoff estimation. A solved example is included.

## Pile Capacity with Pile-Driving Formulas

In this geotechnical engineering blog post, we discuss pile-driving formulas, a well-established but awfully inaccurate approach to bearing capacity of pile foundations.

## Capacity and Level of Service in Basic Freeway Segments

In this transportation engineering blog post, we discuss the theory of highway capacity in basic freeway segments, with emphasis in the concept of level of service. Three solved examples are included.

## Channel Design with the Permissible Velocity and Tractive Force Methods

In this hydraulics blog post, we discuss two of the most well-established methods of design of open channels: The permissible velocity method and the tractive force method. Two design problems are included.

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