4. 2009 ASCE Infrastructure Report
Card
State of US Dams
> 85,000 in US
Average age = 51 years
G.P.A = D (Poor)
4,000 deficient and 1,819 high hazard potential
dams
Unsafe and failure could lead to catastrophic results
Solutions
$2.2trillion over 5 years for all infrastructure
Promote sustainability
5. Pillars of Sustainability
Brundtland Report
Development that meets the needs of the present
without compromising the ability of future generations
to meet their own needs
Economic
Power generation, Water supply, Flood prevention
Environmental
Fish kills, Habitat loss, Nutrient Transport,
Social
New infrastructure, Displacement of locals, Health
issues
6. Economic - Common Purposes
Power Generation
Water Supply
Irrigation
Flood Prevention
Land Reclamation
8. Hydroelectric power
Major Reason for Construction of Large Dams
Considered cheap and clean; An important
renewable energy source
Large portion of US and World Energy
production
An important part of local economies.
13. Water Supply
Important part of water supply infrastructure
Used to store water for use during drier parts
of the year.
Can be part of the water treatment process
Bill Young
Reservoir,
Tampa
Bay
14. Irrigation
Agriculture is a main user of reservoir stored
water.
Large dams often built to divert water from a
river toward dry or desert areas for farmland.
Mixed Economic success
Example: Rivers that feed Aral sea diverted in an
attempt to grow rice, melons, cereals, and cotton.
16. Flood Prevention
Attenuating or balancing Reservoirs
Collect water during high rainfall and release it
slowly over the following weeks or months.
Control of Nile river floods is a prime example
Aswan
High Dam
on the
Nile
17. Land Reclamation
Dams can be built to hold back water for the
purposes of land development
Known as Dykes or Levees.
Prime examples:
New Orleans
Netherlands
Levee,
Netherlands
18. Economic Dangers
Dams/reservoirs susceptible to droughts and
climate change.
Examples:
2001 Northwest drought reduced hydroelectric power
leading to loss of thousands of jobs in the aluminum
industry
Columbia river reservoirs can only store 30% of
annual flow. Earlier snow melts means water is
released too soon for use by customers.
Drought in the US west is causing Water Managers to
limit water withdrawals, to the detriment of local
economies.
19. Environmental - Reservoir
Scale
In the U.S, dams are capable of
storing the equivalent of an
entire year of runoff
Submerged vegetation
Decomposition by
microorganisms
Nutrient release- initial increase
in productivity, potential for
anoxic conditions in benthic
areas
Fish kills- result of seasonal
Hume reservoir in Albury, mixing of anoxic benthic water
Australia Greenhouse gases- reduction of
sequestration, carbon dioxide
and methane release equal to
20. Surrounding Area
Hydrologic cycle
Standing water leads to a
temperature increase
Alteration of evaporation
and precipitation
Initial flooding
Habitat loss and temporary
increase in mortality rates of
wildlife
Mixed effects on local
wildlife
Species specific effects
dependent on adjustment to Shasta Dam reservoir in
newly formed ecotone- California
benefits species such as
waterfowl
21. Downstream
Flow regime
Maintenance of natural
variability levels underlies the
productivity of downstream
ecosystems
Dams often seek to reduce
flow variability, sacrificing
ecological functions
Ecological functions include
matter and nutrient cycling,
providing critical habitat areas,
and nutrient deposit and
transport
Adverse effects on highly
productive estuarine river
deltas, as conditions such as
salinity are dependent upon
river inputs. Ex- decline of the
Colorado delta clam
22. Downstream
Sediment
Lost to downstream
ecosystems through river
impoundments and diversions
Removal of nutrients in
downstream leads to
decreased productivity in both
rivers and connected
ecosystems
Loss of soil fertility on
floodplain. Ex- Aswan Dam in
the Nile Valley
Direct effects on biota
Physical barrier to migration
routes
Can prevent access to critical John Day Dam Fish
breeding Ladder, Columbia
Proposed solutions such as fish River
ladders
23. Social
Benefits
Roads
Jobs
Adverse Effects
Displacement
Health Issue
Very seldom do they
experience the
economic and power
generation benefits
24. Effects due to Globalization
Benefits are often not experienced by those
who were adversely effected by dam
construction
Dams are generally constructed in rural areas
were they produce electricity and move the
electricity long distances to neighboring
industrial areas or cities
The people in the dam region experience
temporary jobs, new infrastructure, and
relocation
25. Displacement
Project Country Number of 40 millions
Resettlers people
Three Gorges China 1,250,000 displaced in
Upper Krishna II India 220,000 the last 10
Sardar Sarovar India 127,000
years
Aswan High Dam Egypt 100,000 Compensati
Kossou Ivory Coast 85,000
on for
Longtan China 73,000
displacemen
t
Mahaweli I-IV Sri-Lanka 60,000
Kariba Zambia and 57,000
River
Zimbabwe degradation
Sbradhino Brazil 55,000
effects on
community
Note: In a ranked table based on the number of resettlers,
the top 10 dams would be in China and India.
Source: Based on Scudder (1997a).
26. Compensation
Lesotho Highlands Water Project
One of the five largest dam projects in the world
Brought infrastructure, roads and some employment
to a previously very rural and poor area of Lesotho
A world class compensation plan was put in place for
those how resettled
The difficultly with compensation is often
quantifying costs
Compensation is often rebuilding houses
More difficult compensation is finding displaced
families viable areas of lands for crops they
previously grew.
27. Health Concerns
Reservoir is a perfect habitat for vectors
Vectors,such as mosquitoes and snails, bring
diseases
Diseases include Malaria and encephalitis
Due to displacement families are driven to
consume unsafe water
Resettled groups live in a denser populated
area resulting in poor hygiene and host of
other diseases
28. Health Impacts
Impact Area Effect of Dam Health Impact
Upstream Loss of biodiversity, increased agriculture, Changes in flood security, water related
catchment sedimentation and flooding, changes in river flow diseases, difficulties with transportation and
and river regime. access to health facilities
Reservoir Inundation of land, presence of large manmade Involuntary resettlement, social disruption,
area reservoir, pollution, changes in mineral content, vector-borne diseases, reservoir induced
decaying organic material seismicity
Downstream Lower water levels, poor water quality, lack of Food security affected on flood plains and
river seasonal variation, loss of biodiversity estuaries (farming and fishing), water-related
diseases, dam
failure and flooding
Irrigation Increased water availability and agriculture, water Changes in food security, vector-borne and water
areas weeds, changes in flow and mineral content, related diseases
pollution
Construction Migration, informal settlement, road traffic Water-related diseases, accidents and
activities increase, hazardous construction occupational injuries
Resettlement Social disruption, pollution, pressure on natural Communicable diseases, violence and injury,
areas resources water
related disease, loss of food security
Country/regio Reduced fuel imports, improved exports, loss of Macro-economic impacts on health, inequitable
nal/global biodiversity, reallocation of funding, sustainability allocation of revenue, health impacts of climate
29. Conclusions
Economic
Global electricity consumption
Fossil fuels – 69%, Nuclear – 13%, Hydropower
– 15%, Other renewables – 3%
Hydropower – Relatively low & constant prices
Water Supply – Drinking and agricultural
irrigation
Flood control and land reclamation
30. Conclusions
Environmental
Reservoir - Greenhouse gas emissions, Fish
kills
Surrounding Area – Habitat loss
Downstream – Altered flow, Sediment
deposition
Social
Benefits – Jobs, New infrastructure
Adverse effects – River degradation, Health
problems
31. Recommendations
Developed World (United States)
Most suitable locations have already been built
up
Only way to improve sustainability is by investing
in maintenance to extend their lifespans
Developing World
The impacts must be well defined
All stakeholders must be involved in the
discussion
Mechanisms must be in place to regulate
operations
Turbines decommissioned in 1968, Recreational use, 38 ft high dam Age – 88 years old2009 ASCE Infrastructure Report Card – Not classified as ‘High’ hazard, 10 in. rain in 12 hrs, Maquoketa rose to 24 ft, 3 flood gates but 1 gate only opened halfway, water overtopped roadway200 ft long portion of Southern embankment eroded away, 8000 people evacuated from downstream cities Monticello and Hopkinton, Emptied lake, Major flood damage, Millions of dollars in damagespoorly maintained