Water Resources and Environmental Engineering Lecture Review

Practice vocabulary flashcards derived from engineering lecture notes covering fluid mechanics, hydrology, and hydraulics.

First-order batch reaction

A reaction in which the concentration at any time $t$ follows an exponential decay function.

Flow mixing junction requirements

Principles stating that the sum of flow in equals total flow out and that flows are mixed completely at the point of discharge.

$90^\circ$ v-notch weir discharge coefficient

The discharge coefficient value for this specific weir type is approximately $2.54$.

Friction loss factors

Variables that cause an increase in loss when they increase, specifically velocity, viscosity, and roughness.

Series pump configuration

A system where two identical pumps are added together to produce a higher head than a single or parallel arrangement.

Head loss at operating point

The loss calculated from the system curve at the operating point; for a system moving water from $1000\,\text{ft}$ to $1040\,\text{ft}$ with an operating head of $153\,\text{ft}$, the head loss is $113\,\text{ft}$.

NPSHA cavitation prevention

Methods to reduce the tendency for pump cavitation, including lowering the pump elevation and increasing the suction pipe diameter.

Manning's roughness coefficient ($n$)

A coefficient estimated based on channel vegetation, degree of channel meandering, and the regularity of channel cross sections, but not the channel slope.

Hydraulic jump

An open channel phenomenon where a rapidly flowing stream abruptly changes to a slowly flowing stream, causing a distinct rise in water level.

Unsteady flow

A classification for flow where the flow rate is increasing with time.

Subcritical flow profile calculation

A determination that must start from the downstream end only.

Sag inlet

The specific inlet location found at the lowest point of a roadway profile, identified as point B in the provided diagram.

Critical flow

The flow type used to determine the maximum contraction of a river width for bridge construction.

Culvert flow variables

Factors affecting flow through a culvert, including entrance type, Manning's roughness, opening area, and tailwater depth.

Station-average method

A rainfall estimation method that assumes the weights applied to each rain gage are equal.

Unit (Unit Hydrograph Theory)

The term used within hydrograph theory to refer to a unit duration of precipitation.

Isohyetal method

The most accurate method for determining average annual precipitation in a catchment basin.

Thiessen Polygon Method steps

A process involving connecting stations with dashed lines, drawing perpendicular bisectors, determining polygon areas, and weighting rainfall values by area.

Floodway fringe

The specific part of a FEMA-regulated floodplain where encroachment is permitted, provided the surcharge does not exceed $1.0\,\text{ft}$.

Time of concentration

The time required for runoff to travel; factors include drainage density and surface roughness, and it increases when land use changes from bare soil to woodlands.

Design storm

A theoretical storm characterized by rainfall intensity, duration, and return period.

Rating curve

A flow-discharge curve where the most important factor is the selection of a specific section of the stream.

Radial flow confined aquifer assumptions

Requirements for defining discharge rate including laminar flow, an isotropic aquifer, and a completely penetrating well.

Hydraulic conductivity ($K$)

A soil property that is a function of water temperature, specific weight, and viscosity; for sand, values can be approximately $25\,\text{m/day}$.

Cone of depression

The shape of the water table drawdown around a pump; when hydraulic conductivity is high, the cone is wide and flat.

Hydrodynamic dispersion

A phenomenon resulting from the combination of molecular diffusion, advection, and mechanical dispersion.