Date post: | 03-Sep-2014 |
Category: |
Technology |
Upload: | mushfiqul-hassan |
View: | 379 times |
Download: | 0 times |
INSIGHTS INTO DAM SUSTAINABILITYECONOMIC, ENVIRONMENTAL, AND SOCIAL
Introduction
Lake Dehli Dam, Iowa
Dam Failure
Lake Dehli Dam Failure
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 $2.2 trillion over 5 years for all infrastructure Promote sustainability
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
Economic - Common Purposes Power Generation Water Supply Irrigation Flood Prevention Land Reclamation
Hydroelectric Power
Dam Cross-Section
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.
As Energy Source in the World
As Energy Source in US
Comparison: Other Energy Sources
Part of Renewable Energy
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
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.
Irrigation
Aral Sea, Central Asia
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
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
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.
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 mixing of anoxic benthic water
Greenhouse gases- reduction of sequestration, carbon dioxide and methane release equal to 4% and 20% of anthropogenic emissions
Hume reservoir in Albury, Australia
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 newly formed ecotone- benefits species such as waterfowl
Shasta Dam reservoir in California
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
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
breeding Proposed solutions such as fish
ladders
John Day Dam Fish Ladder, Columbia River
Social
Benefits Roads Jobs
Adverse Effects Displacement Health Issue Very seldom do
they experience the economic and power generation benefits
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
Displacement
40 millions people displaced in the last 10 years
Compensation for displacement
River degradation 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).
Project Country Number of Resettlers
Three Gorges China 1,250,000
Upper Krishna II India 220,000
Sardar Sarovar India 127,000
Aswan High Dam
Egypt 100,000
Kossou Ivory Coast 85,000
Longtan China 73,000
Mahaweli I-IV Sri-Lanka 60,000
Kariba Zambia and Zimbabwe
57,000
Sbradhino Brazil 55,000
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.
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
Health Impacts
Impact Area
Effect of Dam Health Impact
Upstream catchment and river
Loss of biodiversity, increased agriculture, sedimentation and flooding, changes in river flow regime.
Changes in flood security, water related diseases, difficulties with transportation and access to health facilities
Reservoir area
Inundation of land, presence of large manmade reservoir, pollution, changes in mineral content, decaying organic material
Involuntary resettlement, social disruption, vector-borne diseases, reservoir induced seismicity
Downstream river
Lower water levels, poor water quality, lack of seasonal variation, loss of biodiversity
Food security affected on flood plains and estuaries (farming and fishing), water-related diseases, damfailure and flooding
Irrigation areas
Increased water availability and agriculture, water weeds, changes in flow and mineral content, pollution
Changes in food security, vector-borne and water related diseases
Construction activities
Migration, informal settlement, road traffic increase, hazardous construction
Water-related diseases, accidents and occupational injuries
Resettlement areas
Social disruption, pollution, pressure on natural resources
Communicable diseases, violence and injury, waterrelated disease, loss of food security
Country/regional/global
Reduced fuel imports, improved exports, loss of biodiversity, reallocation of funding, sustainability
Macro-economic impacts on health, inequitable allocation of revenue, health impacts of climate change
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
Conclusions
Environmental Reservoir - Greenhouse gas emissions,
Fish kills Surrounding Area – Habitat loss Downstream – Altered flow, Sediment
depositionSocial Benefits – Jobs, New infrastructure Adverse effects – River degradation,
Health problems
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 Funding must be in place for to continue proper
operation and maintainance into the future
Thank you
Questions?
Hoover Dam,
Nevada