# Author: Krest Engineers

## Bridge Scour Analysis By HEC-18 Equations – Local Abutment Scour (2 of 2)

In addition to NCHRP 24-20 Abutment Scour Approach, FHWA HEC-18 includes two more widely known abutment scour equations - HIRE Equation and Froehlich's Equation. Since both of them are consistently…

## Fall Velocity for Live-bed Contraction Scour Calculation Using HEC-18 Equation

To apply the HEC-18 Equation 6.2 (Figure 1) to calculate the live-bed contraction scour depth, the bed material particle D50 fall velocity needs to be determined to estimate the coefficient…

## Bridge Pier and Abutment Scour Countermeasure Riprap Design by FHWA Hydraulic Toolbox

Hydraulic Toolbox is a powerful tool to design riprap protection for channel banks, culvert outlets, and bridge scour countermeasures. This post is to focus on bridge pier and abutment scour countermeasure…

## Channel Revetment and Culvert Outlet Protection Riprap Design by FHWA Hydraulic Toolbox

Hydraulic Toolbox is a powerful tool to design riprap protection for channel banks, culvert outlets, and bridge scour countermeasures. A brief introduction about riprap is found here for general reference.…

## Bridge Scour Analysis By HEC-18 Equations – Local Abutment Scour (1 of 2)

The bridge contraction scour depth and pier scour depth calculations are explained in the following three posts - Horizontal Contraction Scour, Vertical Contraction Scour (Pressure Flow Scour), and Local Pier…

## Bridge Scour Analysis By HEC-18 Equations – Contraction Scour (2 of 2)

The post here introduces using HEC-18 equation to calculate horizontal contraction scour under non-pressure flow condition and this post is to explain vertical contraction scour (pressure flow scour). When a bridge…

## Bridge Scour Analysis By HEC-18 Equations – Local Pier Scour

Bridge scour analysis is often required to design a new bridge or evaluate an existing bridge. Bridge scour depth is a critical bridge design component for foundation calculation. The scouring…

## Bridge Scour Analysis By HEC-18 Equations – Contraction Scour (1 of 2)

Bridge scour analysis is often required to design a new bridge or evaluate an existing bridge. Bridge scour depth is a critical bridge design component for foundation calculation. The scouring…

## Malcom Small Watershed Hydrograph Method and Its Application in Detention Design

A simple hydrograph development technique, developed by H. Rooney Malcom in 1980, is often used to design detention facilities serving relatively small watersheds (less than 640 acre or 1.0 sq…