george w annandale sustainable water supply and … · august 15, 2017. george w annandale....

AUGUST 15, 2017

GEORGE W ANNANDALE

SUSTAINABLE WATER SUPPLY AND CLIMATE CHANGE

USACE Lakewood, Colorado


DAMS FOR PEOPLE

Dams ARE for People • Domestic Water Supply • Irrigation and Food• Energy • Flood Protection • Recreation • Fisheries • Industrial Water Supply


THE DAM DESIGNER’S NIGHTMARE

SUSTAINABLE DEVELOPMENT OF DAMSRELIABLE WATER SUPPLY

CURRENT FOCUS OF THE PROFESSION

Dam Safety

It is Important

BUT

Does it ensure SUSTAINABLE DEVELOPMENT?


WHY DO WE BUILD DAMS?

ICOLD


WHAT IS SUSTAINABLE DEVELOPMENT?

“Sustainable development seeks to meet the needs and aspirations of the presentwithout compromising the ability to meet those of the future”

Brundtland Commission Report: “Our Common Future (1987)”


INTERGENERATIONAL EQUITY


Focused on FAIRNESS BETWEEN GENERATIONS

Environmental Stabilization • A DESIRABLE CONSEQUENCE of Sustainable Development

• NOT THE OBJECTIVE of Sustainable Development

INTERGENERATIONAL EQUITY


SUSTAINABLE DEVELOPMENT


RENEWABLE resources are used at a RATE that is smaller than its RATE of regeneration

EXHAUSTIBLE resources are used at a RATE that is smaller than the RATE of development of renewable substitutes, and

POLLUTION does not exceed the RATE by which the environment can assimilate it.

• Herman Daly

HOW TO SUSTAINABLY DEVELOP A RESOURCE


Acce

ssib

le F

resh

Gro

undw

ater

WATER RENEWABLE OR EXHAUSTIBLE?

7,972mi

864m

i

10m

i

All

Wat

er o

n Ea

rth

All R

iver

s

42m

i

EXHAUSTIBLE RENEWABLE


GROUNDWATER OR RIVER WATER?POTENTIAL FOR SUSTAINABLE DEVELOPMENT

Residence Time = 1,400 years Residence Time = 16 to 18 days

Daily Use of Water

RT >>>> Usage RT ~ Usage


GROUNDWATER FOOTPRINTGLOBAL FOOTPRINT = 3.5

Western MexicoHigh Plains

North Arabian

PersianUpper Ganges

North China Plain

27 9 48 20 545

Aquifer Area (AA)

Groundwater Footprint (GF)


RIVER WATERPREFERRED SOURCE OF FRESH WATER


LOW HYDROLOGIC VARIABILITY RUN-OF-RIVER SYSTEMS

Daily Renewal

Variable Flow

Need for Run-of-River Storage to Supply during Low Flow Season

River Flow

Water Shortage

Water Demand


HIGH HYDROLOGIC VARIABILITYMULTIPLE YEAR DROUGHTS AND WATER SUPPLY

11 Years

Multiple Year Storage Required


RUN-OF-RIVER AND CARRYOVER STORAGE REGIONS

( )

2 2

24 1v

crit

z cn γ

α

⋅=

⋅ −

RUN-OF-RIVER

CARRYOVER STORAGE


WATER SUPPLY RELIABILITY NO STORAGE

' 1 vc zγα = + ⋅

HIGH VARIABILITY

LOW VARIABILITY

90%


WATER SUPPLY RELIABILITY HIGH VARIABILITY WITH STORAGE

' 1 vc zγα = + ⋅

HIGH VARIABILITYNO STORAGE

HIGH VARIABILITY

WITH STORAGE= 1 X MEAN ANNUAL FLOW

2 2

14

vz cγατ⋅

= −⋅

90%


CLIMATE CHANGE AND WATER SUPPLYTWO IMPORTANT VARIABLES

CHANGE IN MEAN ANNUAL RIVER FLOW

CHANGE IN HYDROLOGIC VARIABILITY


CLIMATE CHANGEMEAN ANNUAL FLOW INCREASE/DECREASE


INCREASED HYDROLOGIC VARIABILITYGREATEST IMPACT ON RELIABILITY OF WATER SUPPLY


CLIMATE CHANGEHOW MUCH WOULD VARIABILITY INCREASE

Current Conditions

( )

2 2

24 1v

crit

z cn γ

α

⋅=

⋅ −

Assume 25% Increase in Variability


Increased Hydrologic Variability due to Climate Change

Reduction in Yield

To Maintain Reliability of Water Supply • Hydrologically LARGE

Reservoir Storage

HOW TO PREPARE FOR CLIMATE CHANGE:DESIGN, BUILD AND MAINTAIN ROBUST INFRASTRUCTURE

2 2

14

vz cγατ⋅

= −⋅

Storage = 0.6MAF

1.0MAF

2.0MAF


GLOBAL POPULATION ANDDAM CONSTRUCTION

Population Gross Reservoir Volume


RESERVOIR SEDIMENTATION –THE STORAGE SPACE ENEMY


STORAGE LOSS TO SEDIMENTATION

Graf et al. Sedimentation and Sustainability


NET STORAGE IN US DAMS


GLOBAL STORAGE IN LARGE DAMS To

tal N

et V

olum

e (k

m3 )

TotalPer Capita

Per C

apita

Vol

ume

(m3 /p

erso

n)


LIMITED NUMBER OF DAM SITESCONSEQUENCE OF CURRENT DEVELOPMENT POLICY

Cum

ulat

ive

Yiel

d (1

06m

3 /yr)

US$/m3 yield

LOST TO SEDIMENTATION

DEMAND FOR WATER


FUTURE GENERATIONSCONSEQUENCE OF CURRENT DEVELOPMENT POLICY

Cum

ulat

ive

Yiel

d (1

06m

3 /yr)

US$/m3 yield

SEDIMENTATION

NEED MORE DAMS AT HIGHER COST

Cum

ulat

ive

Yiel

d (1

06m

3 /yr)

US$/m3 yield

INADEQUATE STORAGE SPACE

Cum

ulat

ive

Yiel

d (1

06m

3 /yr)

US$/m3 yield

NO STORAGE SPACE LEFT


MAKING THE RIGHT CHOICERESERVOIR SEDIMENTATION MANAGEMENT OPTIONS

Manage amount of sediment generated by the catchment

Allow sediment inflows to pass through or around the reservoir

Remove sediment which accumulates in the reservoir

Upstream Management

Check Dams

Forestation

Sediment Routing

Sluicing

Density Current Venting

Bypass

Sediment Removal

Dredging Excavation Hydro-suction Pressure Flushing Drawdown Flushing


DUAL NATURE OF RESERVOIR STORAGE RENEWABLE OR EXHAUSTIBLE – A DELIBERATE CHOICE


CURRENT ECONOMIC ANALYSIS APPROACH

No Assignment of Cost due to Storage Loss

0 0

n nt t

tt t

NPV B d A C d= =

= ⋅ − − ⋅∑ ∑

1(1 )

dr

=+


PV(D) <<< D

CURRENT ECONOMIC ANALYSIS APPROACHCONVENTIONAL REASONING FOR IGNORING LOSS

0 0

n nt t

tt t

NPV B d A C d= =

= ⋅ − − ⋅∑ ∑

D


CORRECT ECONOMIC ANALYSIS APPROACHHOTELLING PRINCIPLE

0 0

n nt t

tt t

NPV B d A C d D= =

= ⋅ − − ⋅ −∑ ∑PV = D

Hotelling: Value of an Exhaustible Resource increases with the discount rate (i.e. Discounted value does not change)

D


ECONOMIC VIABILITYHOTELLING PRINCIPLE

Example Project

NPV

(Milli

on U

S$)


DESIGN AND OPERATIONPARADIGM SHIFT REQUIRED

Conventional Design Life Approach

Planning & Design Construction O&M Disposal


DESIGN AND OPERATIONNEW PARADIGM

Preferred Approach: Life-Cycle Management Approach

Planning & Design Construction

O&M

Refurbishment

Sediment Removal

SUSTAINABLE WATER SUPPLY AND CLIMATE CHANGE Gross Dam, Colorado

Key Messages

Sustainable Development

Create Intergenerational Equity

Environmental Conservation Desirable ConsequenceNot the Objective

SUSTAINABLE WATER SUPPLY AND CLIMATE CHANGE Gross Dam, Colorado

Key Messages

Preferred Water Source

Rivers have greatest potential for Sustainable Development

SUSTAINABLE WATER SUPPLY AND CLIMATE CHANGE 42

Thika Dam, Kenya

Key Message

Climate Change Impacts

Greater Need for Storage


Key Messages

Net Loss of Reservoir Storage Space

Losing More Storage than Adding

SUSTAINABLE WATER SUPPLY AND CLIMATE CHANGE Karahnjukar Dam Spillway, Iceland

Key Messages Preserve Reservoir Storage

Existing ReservoirsFuture Reservoirs

Life Cycle Approach

SUSTAINABLE WATER SUPPLY AND CLIMATE CHANGE Strontia Springs Dam, Colorado

Key Messages Feasibility of Sustainable Development

Dual Nature of Storage Deliberate Choice by Designer Exhaustible – Let Fill with Sediment Renewable – Manage Sediment

Economic Analysis Implications


ANTI-DAM SENTIMENT JEOPARDIZES OUR COMMON FUTURE


ENGINEERING LEADERSHIP

Intergenerational Equity Reliability of Water Supply Climate Change Create and Preserve Reservoir

Storage

Be the Voice of Reason

John BriscoeWorld Bank Engineer

Dams AdvocateDeceased 2014


REFERENCE

Annandale, G. 2013. Quenching the Thirst – Sustainable Water Supply and Climate Change, CreateSpace, Charleston, SC


REMOVE DAMS – CONSERVE WATER WATER CONSERVATION IN THE US

USGS Data

A “Band-Aid” with limits

1975


WORLDWIDE WATER CONVERSATION NOT THE MAGIC BULLET

george w annandale sustainable water supply and … · august 15, 2017. george w annandale....

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