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
2009 ASCE Infrastructure ReportCard 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
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 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.
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 processBill YoungReservoir,TampaBay
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.
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 seasonalHume reservoir in Albury, mixing of anoxic benthic waterAustralia Greenhouse gases- reduction of sequestration, carbon dioxide and methane release equal to
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
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 John Day Dam Fish breeding Ladder, Columbia Proposed solutions such as fish River ladders
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 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 communityNote: 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).
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 ImpactsImpact Area Effect of Dam Health ImpactUpstream Loss of biodiversity, increased agriculture, Changes in flood security, water relatedcatchment sedimentation and flooding, changes in river flow diseases, difficulties with transportation andand river regime. access to health facilitiesReservoir 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 seismicityDownstream Lower water levels, poor water quality, lack of Food security affected on flood plains andriver seasonal variation, loss of biodiversity estuaries (farming and fishing), water-related diseases, dam failure and floodingIrrigation Increased water availability and agriculture, water Changes in food security, vector-borne and waterareas weeds, changes in flow and mineral content, related diseases pollutionConstruction Migration, informal settlement, road traffic Water-related diseases, accidents andactivities increase, hazardous construction occupational injuriesResettlement Social disruption, pollution, pressure on natural Communicable diseases, violence and injury,areas resources water related disease, loss of food securityCountry/regio Reduced fuel imports, improved exports, loss of Macro-economic impacts on health, inequitablenal/global biodiversity, reallocation of funding, sustainability allocation of revenue, health impacts of climate
ConclusionsEconomic 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
ConclusionsEnvironmental 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