Introduction to Hydrology and Hydraulics

7/28/2019 Introduction to Hydrology and Hydraulics

1/106

Introduction to Hydrology and

Water & Environmental Engineering Soc.

Prof. Michael Bruen, MIEI, C.Eng.

UCD Centre for Water Resources Research

School of Architecture, Landsca e and Civil

Engineering, UCD


2/106

UCD Centre for Water Resources ResearchMichael Bruen

Contents 1 - Hydrology

Purpose of Lecture

Hydrological cycleHydrological data sources

Flow duration curves

Design flood estimation

Reservoir storage-yield calculations

Base flow estimation

Hydrological models


3/106


Hydrologydeals with the occurrence, circulation and distribution

of the waters of the earthShaw, E.M., Hydrology in Practice,Van

, ,

The hydrosciences deal with the waters of the earth; theirstr ut on an c rcu at on, t e r p ys ca an c em ca

properties and their interaction with the environment, including

interaction with living things and, in particular, human beings.

y ro ogymay e cons ere o encompass a e

hydrosciences.Chow, V. T., Maidment, D.R. & Mays, L.W. Applied

Hydrology, McGraw Hill, New York, 1988

The business ofhydrologyis to solve the water balance equationto his own suggested definition of hydrology as the science that

see s to exp ain an quanti y t e water a ance ynamics or any

defined spatial scale (from a point to global) and temporal scale

(from seconds to years) and their relationships with the physicalan c em ca ranspor o ma er roug e y ro og ca cyc e

and with ecology. (Lee, 1990)

hi h l


4/106


Hydrological Cycle

UCD C f W R R hMi h l B


5/106


Precipitation

M n T R in n H il Mi r l

Measured as a depth (mm)

Man t es ( e. . oro ra hic, frontal, convective)Different scales of time and space

Highly variable in time and space

Estimated by raingauge, distrometer, radarFrequency, Duration, Intensity relationship important for

es gn.

Intense rain rates cause direct surface runoff, river floods

Lighter rainfall has time to infiltrate into the ground and

recharge groundwater

UCD C t f W t R R hMi h l B


6/106


Soil Erosion

UCD Centre for Water Reso rces ResearchMichael Br en


7/106


Forest Road



8/106


Duration

(Min)

Depth

(mm)

Rate

(mm/min)

Location Date

. arot, ua e oupe

8 126 15.750 Fussen, Bavaria 25/05/1920

15 198 13.200 Plumb Point, Jamaica 12/05/1916

. - - ,

42 305 7.262 Holt, Misssouri 22/6/1947

130 483 3.715 Rockport, West Virginia 18/7/1889

'. ,

270 782 2.896 Smethport, Pennsylvania 18/7/1942

540 1087 2.013 Belouve, La Reunion 28/2/1964

1110 1689 1.522 " " 28/2/1964

1440 1870 1.299 Cilaos, La Reunion 15/03/1952

5760 3504 0.608 " " 14/3/1952

10080 4110 0.408 " " 12/3/1952

21600 4798 0.222 Cherrapunji, India 24/6/1931

132480 16369 0.124 " " May-July/1861

263520 22454 0.085 " " April-Sept/1861

525600 26461 0.050 " " Aug/1860-July/1861

1052640 40768 0.039 " " 1860-1861



9/106


World

100000

10000

1000

ofrainfall(mm)

100

De

pt

10

1 10 100 1000 10000 100000 1000000

Duration (min)World



10/106


100000

10000

49.075.6 dp =

1000rainfall(mm)

Depth

of

10

1 10 100 1000 10000 100000 1000000

Duration (min)World depth duration relationship



11/106


100000

10000

49.075.6 dp =

infall(mm)

Depthofr

100

10

1 10 100 1000 10000 100000 1000000

Duration (min)World Ireland depth duration relationship



12/106


Intensity Duration relationship for extremes

100.00

World Ireland10.00

(mm/min)

1.00

Rainfallr

ate

0.10

0.01

1 10 100 1000 10000 100000 1000000

Duration (min)



13/106

Interception

Water caught before reaching the ground, usually

by vegetation - on leaves, branches and trunks,which is evaporated back into the atmosphere.



14/106

Evaporation / Evapotranspiration

vapora on s w en wa erchanges from liquid to gaseous

form and mixes in theatmosphere. This requires

Energy

laden air)

Evapotranspiration is theevaporation of water which has

been taken up by the roots of

through the stomata on theirleaves.



15/106

Surface Runoff

Water which neither evaporates nor infiltrates runs

over the surface of the ground. It mayreach a channel and become part of the flood

soak into the ground at a drier location

evaporate

Runoff coefficient is the ercenta e of the rain

reaching the ground that flows off in the relevant

time eriod Note: scale and time de endent



16/106

InfiltrationWater soa ng nto t e groun

Rate depends onprecipitation rate,

type of ground surface

slope of ground surface, and

soil moisture condition.

Impervious means no infiltration, many such areasin r n n ir nm n



17/106

Percolation

Water which has entered the soil can move,

usually downwards or sidewards. It mayBe taken up by roots and transpired

Reach the watertable and recharge groundwater, or

Emerge as a spring, or

Seep into river or lake



18/106

Groundwater

When water reaches the water table it moves as

groundwater and may emerge elsewhere asexfiltration

Emerge as a spring

into lakes or rivers

into the sea



19/106

Aquifers

Unconfined, shallow, large recharge rates but can

be vulnerable to contaminationConfined, deeper, slower recharge, protected from

contamination

,

Karstic.



20/106

Data Sources (some online) - 1Dischar e

OPW

EPAESB

Local Authorities

PrecipitationMet Eireann

Local Authorities and some other state organisation

Water Quality parameters

EPA

Local Authorities



21/106

Data Sources (some online) - 2

Met Eireann

TGroundwater levels

Topology

Land use

Soil types



22/106



23/106



24/106



25/106



26/106



27/106



28/106



29/106



30/106



31/106



32/106

Flow Duration Curve (FDC) - Introduction

Graph of the average percentage of time a flow is

exceeded.

ert ca ax s genera y ow

Easily constructed with a spreadsheet



33/106

spreadsheet (simplest way)

Required: Sufficient flow data ( say n values) at

suitable time intervals.Sort the data in descending order of magnitude

,

Scale the index to a percentage by multiplying by

an v e y n

Plot the sorted data (vertical axis) vs. the scaledindex and this is your FDC.



34/106

Flow duration curve Dongola River, Sudan

1000

1200

600

800

te(m^3/s)

200

400flow

ra

0

0 10 20 30 40 50 60 70 80 90 100

% of time flow is exceeded



35/106

Flow duration curve Don ola River Sudan

1000

100

rate(m^3/s)

flow

10

0 10 20 30 40 50 60 70 80 90 100

% of time flow is exceeded



36/106

Flow Duration Curve - Uses

Hydropower calculate energy available for agiven installed generating capacity

Visualise effects of stora es in s stem on riverregime

Summarise impacts of structures or management

o tions on flows in a river



37/106

Flow Duration and Energy Calculation : Dongola River Sudan (FREQUENCY method)

efficiency = 0.9 0.008829 Bruen / 2008 Annual

N= 4752 (M M Fs) 47.52 0.0876 Annual Energy Energy per

Flow Indicative Num ber of % of Power per per m etre head m eter head

Ranges Flow values values Cum ul. m eter head (for each range) GW -hr/m

(cum ecs) (cum ecs) in range in range % M W /m GW -hr/m (cum ulative)

0 100 0 0

50 25 46 0.97 100.00 0.22 0.01 0.01

100 75 2493 52.46 99.03 0.66 2.03 2.04

150 125 746 15.70 46.57 1.10 1.21 3.25

200 175 286 6.02 30.87 1.55 0.70 3.95

250 225 224 4.71 24.85 1.99 0.73 4.68

300 275 162 3.41 20.14 2.43 0.66 5.34

350 325 111 2.34 16.73 2.87 0.54 5.88

400 375 65 1.37 14.39 3.31 0.37 6.25450 425 115 2.42 13.03 3.75 0.75 7.00

500 475 89 1.87 10.61 4.19 0.65 7.65

550 525 124 2.61 8.73 4.64 1.01 8.66

600 575 86 1.81 6.12 5.08 0.77 9.43

650 625 47 0.99 4.31 5.52 0.46 9.89

700 675 57 1.20 3.32 5.96 0.60 10.49

750 725 26 0.55 2.13 6.40 0.30 10.79800 775 28 0.59 1.58 6.84 0.34 11.13

. . . . .

900 875 14 0.29 0.69 7.73 0.19 11.51

950 925 17 0.36 0.40 8.17 0.25 11.76

1000 975 2 0.04 0.04 8.61 0.03 11.79

o a nergy .

(GW -hr/m head)



38/106

Run-of-river Hydropower: Energy vs. Installed Capacity Dongola River, Sudan.

14.00

10.00

12.00

eter/year)

4.00

6.00

.

ergy(GW-h

rs/

0.00

2.00

E

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00

Installed capacity (MW)



39/106

emons ra es orage ec s

Effect of storage on flow regime - normalised flow duration curves

3

2

2.5

(cumecs)

1.5

meanflow

0.5

1

fra

ctiono

0

0 10 20 30 40 50 60 70 80 90 100

% of time flow is exceededBlackwater at Ballyduff (no storage) Corrib at Galway (storage effect)



40/106

FDC shows effects of impoundment


41/106

Flood Fre uenc Anal sis



42/106

Design Flood Estimation if data available

Preferable : From data (annual maximum series)

If no data then from catchment characteristics

, ,

some ata per aps u est mate rom ata an

alpha from other information.



43/106



44/106

Frequency / Probability Concepts

Event Occurrence or exceedance of a specified discharge

(flow rate)

Return Period (T) long term average time (in years)between occurrence of event (not that intuitive, particularly

1=

T

chance, or odds e.g. 1/100 chance



45/106

Events are assumed uncorrelated (one years maximum doesntinfluence any other years maximum)

If p is the probability that a flood discharge is equalled orexceeded in any one year then (1-p) is the probability itwill not happen in any one year

p3 is the probability it will happen in any specified 3 years

-p s e pro a y w appen n anyspecified 3 years.



46/106


ea s over res o no use regu ar y


47/106

ea s over res o no use regu ar y


nnua ax ma use regu ar y


48/106

nnua ax ma use regu ar y


Pl tti P iti


49/106

Plotting Positions

Theory Populationi

p =

Sample Gringorten44.0i

Sample Cunnane 12.0+n

2.0

4.0

+

=n

ip



50/106



51/106

[ Extreme Value Type 1 (EV1) ]

=

uqqF expexp)(

1

TT

=

Tuq

T1lnln


um e s r u on


52/106

[ Extreme Value Type 1 (EV1) ]

=

uqqF expexp)(

== pqF1

11)(

= TuqT1

1lnln



53/106



54/106



55/106



56/106


Fitting Parameters to data


57/106

Fitting Parameters to data

Method of Moments

Maximum likelihood

Probability weighted moments


e o o omen s


58/106

7797.0 =

5772.0 =u

andmeantheiswhere

deviationstandardtheis

seriesmaximaannualtheof



59/106


Maximum Likelihood Method


60/106

Maximum Likelihood Method

Maximise the likelihood

function (probability of getting

the observed data series AM

values)

uquq in

in 1

Easier to work with lo arithms ==

ii

i,

11

- minimise the negative of this

( ) =

+

+=

n

i

ii uququNLL1

exp)ln(,



61/106

Annual Maximum Series Analysis for Barrow at Royal Oak

350

400

250

300

umecs)

150

200

Discharge(c

50

100

0

1.00 10.00 100.00 1000

Return period (years)

Data Series Moment estimate


Design Flood Estimation if no data available


62/106

Design Flood Estimation if no data available

Flood Studies Report (FSR) 1974 covers Great

Britain and Ireland.

United Kingdom replaceing FSR there. Uses GIS

Flood Studies Update (OPW) 2010 for Ireland.ew ra n a ana yses ava a e


New Rainfall Analysis


63/106

New Rainfall Analysis

Fitzgerald, D. L. (2007) Estimation of point

rainfall frequencies.

New Rainfall depth-duration-frequency

relationshi usin data from 1941-2004

Index rainfall plus multiplier


Climate Change C4I


64/106

Climate Change C4I

Increase of about 15% in winter rainfall

Drier summers with 20% less rain in some areas

(E & SE)

- -

and 5-day extremes)


Base Flow Estimation


65/106

Base Flow Estimation

Debate/differences on what is covered by

definition of term base flow.

water interaction literature review on hydrograph.


Reservoir Storage yield


66/106

g y

Problem: Determine the storage volume required

in a reservoir to meet a particular demand (yield)

pattern with a specified (small) probability offailure.

Methods:Mass-Curve constant ield and no robabilit of

failure)

State Transition Matrix methods

Simulation


Source of problem


67/106

p

Swilly at New Mills Mean Monthly Flows

6.0

4.0

5.0

3.0

cumec

s

1.0

2.0

0.0

1973 1974 1975 1976 1977 1978 1979 1980

Years


Classical Mass-curve


68/106

Swilly at New Mills Mass Curve

500.0

350.0

400.0

450.0

3)

250.0

300.0

veVolume(M

illionm^

100.0

150.0

200.0

Cumulati

0.0

50.0

1973 1974 1975 1976 1977 1978 1979 1980

Years


Mass curve analysis


69/106

y

400 12.0

.

200

300

(Mm

^3)

8.00

10.0

100

Cumulat

iveVolume

6.00

-100

0

2.00

4.00

-200

1973 1974 1975 1976 1977 1978 1979 1980

Time

0.00


Purpose of Hydrologic Modelling


70/106

p y g g

Explore Scientific understanding Scientific Method is to

test hypotheses

Help understand complex dynamic relationshipsAnalyse and interpret data

Determine sensitivities to input data, parameter values and

spatial scales

as s o managemen oo s or po cy ormu a on

Operational Manage (including online control)es gn o mon tor ng systems comp ance

Design of Measures


o e ng ssues


71/106

Spatial Scale

rocess e a comp ex yParameter estimation / ill-conditioning / equifinality / uncertainty /

uzzy met o s

Validation (independent data)

Flexibility / Robustness

Models for management more physically-based ?Understanding and communicating limitations -


Models - Types


72/106

Physical models (full or reduced scale)

Analog models

Numerical models


Models Numerical - Types


73/106

Empirical (black box)

Conceptual

Process based


Treatment of Spatial variation


74/106

Lumped models

Semi-distributed models

Distributed models


SMAR model schematic


75/106


HBV model (SMHI)


76/106

UCD Centre for Water Resources ResearchMichael BruenComponents of the flow routine in the SHETRAN modelComponents of the flow routine in the SHETRAN model


77/106

Evapotrnaspiration loss modelEvapotrnaspiration loss model

Canopy interception modelCanopy interception model

Snow melt modelSnow melt model

Overland flow & Channel modelOverland flow & Channel model


Steps in Modelling - I


78/106

Define Purpose of modelling

Determine information availability

Resources available

Choose modelling approach

Choose existing model or develop new model


Steps in Modelling - 2


79/106

Calibrate model (optimisation)

Validate model s lit sam le test

Parameter sensitivity


Model development


80/106


Model calibration


81/106


Typical widely-used models used


82/106

Unit hydrograph (flood events only)

SMAR UCG-DEH

Scandanavian models (HBV and NAM)

TOPMODEL

SHETRAN

IHACRES


Modelling Water Dynamics in SWATModelling Water Dynamics in SWAT


83/106

g yg y

Interception

Infiltration

Evapotranspirationa era ow

Subsurface flow

Percolation

Non-point Pollution


Conceptual representation in the HSPF modelConceptual representation in the HSPF model


84/106

SURFACE FLOW

INTER FLOW

UPPER ZONE

INTER FLOW ZONE

LZS

INEXP

IBARINDIMAXLSZ

LZSNINFILTIBAR

=

=LOWER ZONE

LZSN2RTFRATIO =

INFILT: infiltration arameter

BASE FLOW

LZSN: nominal lower zone storage

LZS: actual lower zone storage

INEXP: exponent parameter

IND: ratio of max. to mean infiltration capac.

ZONE

Courtesy : Mrs. Igbal Salah Mohammed


Contents - 2 - Hydraulics


85/106

Open channel hydraulics

H draulic models

Downstream control

Floodplain

Flood Risk Management hydraulic options


Hydraulics


86/106

Definition : The study of fluids in motion.

For us:

Engineering focus applied knowledge

Here I w concentrate on Hy rau cs n R ver

Engineering


River Engineering aspects


87/106

Flooding

Trans ort

Morphology

River crossings (bridges and culverts)

Water Quality


Governing Equations:- Steady State


88/106

20 SSdy f=

X : distance along channel

S0 : channel bed slope

2 34RA

Qn

Sf =

Fr : Froude number

2

2 TQ

n : Mannings n

T A R : Area To -width3

gA hydraulic radius (allgeometric properties)


For stead flow and sim le eometries these can be

solved in a spreadsheet:0 7


89/106

0.7

0.4

0.5

0.6

(m)e.g. drawdown

0.2

0.3

Elevation

curve

0

0.1

-35 -30 -25 -20 -15 -10 -5 0

Distance from end of channel (m)

(-ve means

Wetted Hydraulic upstream)

Depth top width Area Perimeter Radius Velocity Fr2 Sf dy/dx Delta-X Distance

(m) (m) (m2) (m) (m) (m/s) (m) (m)

0.475 1.000 0.475 1.950 0.244 2.105 0.951 0.00492 -0.080325 0. . . . . . . . - . - . - .

0.515 1.000 0.515 2.030 0.254 1.942 0.746 0.00397 -0.011697 -1.210 -1.603

0.535 1.000 0.535 2.070 0.258 1.869 0.666 0.00359 -0.007737 -2.058 -3.661

0.555 1.000 0.555 2.110 0.263 1.802 0.596 0.00326 -0.005587 -3.002 -6.664

0.575 1.000 0.575 2.150 0.267 1.739 0.536 0.00297 -0.00424 -4.070 -10.734

0.595 1.000 0.595 2.190 0.272 1.681 0.484 0.00271 -0.003319 -5.292 -16.026

0.615 1.000 0.615 2.230 0.276 1.626 0.438 0.00249 -0.002651 -6.700 -22.7260.635 1.000 0.635 2.270 0.280 1.575 0.398 0.00229 -0.002145 -8.341 -31.067


St Venant E uations(1-D Unsteady Open Channel Flow)


90/106

AQ

tx

momentum

0

1 0

=+

+

+

Puuuz

xgtgx



91/106


Linear Analysis ( Kundzewicz & Dooge, 1989)


92/106


Hydraulics: Factors in choice of numerical model


93/106

Choice of model

1-D (typical) ; 2-D (river morphology) or 3D (e.g.

scour or approaches to constrictions)Steady or unsteady if flood attenuation isrelevant

Water Quality issues important (?) WFD

Links with other models


30velocity 14400

5.60024


94/106

10

20

4.55019

4.7252

4.90021

5.25022

.

0

0 25 50 75 100 125 150

3.50015

3.67516

4.02517

4.20018

2.62511

2.80012

2.97513

3.32514

Example 2-D model : courtesy Mr. Aodh Dowley

velocity 14400

1

1.40006

1.57507

1.92508

2.10009

.

0.525022

0.70003

0.875037

1.22505

0

0.175007


xamp e - mo e ou pu our esy r. e na e r


95/106

Run 1

Run 2Run 2

Run 3


Choice of models 1D


96/106

HEC-RAS (1-D) (USACE)

MIKE 1-D Danish H draulics Inst.

ISIS (Wallingford UK & Halcrow ) 1-D

Many others


Choice of models 2D and 3D


97/106

TELEMAC (EDF & HRWallingford)

MIKE (2-D and 3D)(Danish Hydraulics Inst.)

Surface Water Modelling System (SMS)

more ..


Basic Requirements - 1

S f h l d fl d l i li i


98/106

Survey of channel and floodplain explicit cross-sections, linked with DTM, aerial or satellite

p o ograp s an or maps.

u c ent eta to proper y represent c anges n

geometry; constrictions, changes in slope, structures

Limits : hydraulic control to u/s of point of interest.


Basic Requirements 2

l f i


99/106

Values of Mannings n

Water level and flow data for calibration and validation

gauges, photos, marks on roads or buildings, debris

lines in fields, debris in branches of trees.

Flow measurements (rating curve)

Initial estimates from published literature.


Modelling Interfaces

Ri / if


100/106

River / aquifer

River / flood lain

Soil / Vegetation / Atmosphere



101/106

Example : Shannon at Limerick



102/106



103/106



104/106


* 5399.1 5263Paramad Coms

1937

1857.5*

*

Paramaddawes

.5080

Pa r amaddawes

.

1698.5*

1619

Paramad u/s

1486

1390

1332 1285

Pa

ra10301

Junct4

1165

ad

10345


105/106

1165

11061053

u/s

Nanny u/s10619

10527.6*

10436.3*

10345

Nanny-mid10267

10059

9814.*

9535*

Nanny-Parama

10941

10860.5*

10780.*

. .

9100.16*8906.5*

8712.83*

8535.80*8375.40*

8118.*

Nanny

-mid

N

anny

u/s

.

7692.75*

7443

72186882.80*

6742.40*6602

6415

6230.*


ens v y o s oun ary

22

Revisited2001b Plan: Duleek Flood Study Plan

Geom: Duleek Flood Study Geometry Flow: Duleek Flood Study Flow Data

Le end

Nanny-mid Nanny u/s

WS PF 8


106/106

20

WS PF 8

WS PF 7

WS PF 6

WS PF 5

WS PF 4

18

WS PF 3

WS PF 2

Crit PF 4

Crit PF 2

Crit PF 5

16

Elevation(m)

r

Crit PF 6

Crit PF 1

Crit PF 7

WS PF 1

Crit PF 8

14

Ground

LOB

ROB

12

0 1000 2000 3000 4000 5000

Main Channel Distance (m)

Documents

Introduction to Hydrology and Hydraulics