Download presentation

1
**Groundwater Flow Equations**

Groundwater Hydraulics Daene C. McKinney

2
**Summary General Groundwater Flow Confined Aquifer Flow**

Control Volume Analysis General Continuity Equation Confined Aquifer Flow Continuity Equation Integrate over vertical dimension Transmissivity Continuity Examples Unconfined Aquifer Flow Darcy Law

3
**Control Volume Control volume of dimensions Dx, Dy, Dz**

Completely saturated with a fluid of density r x y z Mass flux in Mass flux out Control volume

4
**Mass Flux Mass flux = Mass in - Mass out: Fluid mass in the volume:**

mass flux in mass flux out Mass flux = Mass in - Mass out: Fluid mass in the volume: Continuity: Mass flux = change of mass

5
Aquifer Storage

6
Continuity Equation

7
Confined Aquifer Flow

8
**Horizontal Aquifer Flow**

Most aquifers are thin compared to horizontal extent Flow is horizontal, qx and qy No vertical flow, qz = 0 Average properties over aquifer thickness (b) Ground surface Bedrock Confined aquifer Qx K x y z h Head in confined aquifer Confining Layer b

9
**Aquifer Transmissivity**

Transmissivity (T) Discharge through thickness of aquifer per unit width per unit head gradient Product of conductivity and thickness Hydraulic gradient = 1 m/m Potentiometric Surface Confining Bed Confined Aquifer b 1 m Transmissivity, T, volume of water flowing an area 1 m x b under hydraulic gradient of 1 m/m Conductivity, K, volume of water flowing an area 1 m x 1 m under hydraulic gradient of 1 m/m

10
**Continuity Equation Continuity equation Darcy’s Law Continuity**

Ground surface Bedrock Confined aquifer Qx K x y z h Head in confined aquifer Confining Layer b Radial Coordinates

11
**Example – Horizontal Flow**

Consider steady flow from left to right in a confined aquifer Find: Head in the aquifer, h(x) Ground surface Bedrock Confined aquifer Qx K x y z hB Confining Layer b hA L steady flow Head in the aquifer

12
**Example – Horizontal Flow**

L = 1000 m, hA = 100 m, hB = 80 m, K = 20 m/d, f = 0.35 Find: head, specific discharge, and average velocity Ground surface Bedrock Confined aquifer Qx K=2-m/d x y z hB=80m Confining Layer b hA=100m L=1000m

13
**Unconfined Aquifer Flow**

14
**Flow in an Unconfined Aquifer**

Dupuit approximations Slope of the water table is small Velocities are horizontal Ground surface Bedrock Unconfined aquifer Water table Dx Qx K h x y z

15
**Steady Flow in an Unconfined Aquifer**

1-D flow Steady State K = constant h Flow hA hB Water Table Ground Surface Bedrock L x

16
**Steady Flow in an Unconfined Aquifer**

K = 10-1 cm/sec L = 150 m hA = 6.5 m hB = 4 m x = 150 m Find Q h Flow hA=6.5m hB=4m Water Table Ground Surface Bedrock L=150m x K=0.1cm/s

17
**Summary General Groundwater Flow Confined Aquifer Flow**

Control Volume Analysis General Continuity Equation Confined Aquifer Flow Continuity Equation Integrate over vertical dimension Transmissivity Continuity Examples Unconfined Aquifer Flow Darcy Law

Similar presentations

Presentation is loading. Please wait....

OK

Boundaries and Superposition

Boundaries and Superposition

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on role of entrepreneur in economic development Supply and demand elementary ppt on cells Ppt on unique identification system Ppt on models of marketing communication Ppt on steve jobs as entrepreneur Download ppt on hazards of mining Ppt on population census 2011 Complete ppt on hepatitis b Ppt on school management system software Ppt on earth movements and major landforms in california