assignment mumtaz

7/31/2019 Assignment Mumtaz

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Environmental Impact Assessment Course Code 1584

M.Sc Environmental Design Page 1 of 37

A. OBJECTIVE OF THE STUDY

The objective of the study was to assume that you have been assigned theconstruction of a Dam Project. Being the Project Manager of a Dam Project; Iwas required to:

A. Prepare a Proposal for Design and Construction of the Project.B. Select team the team for the Project and explain how you will manage the

team.

B. METHODOLOGY FOR RESEARCH

I have been working on Dam and hydropower projects for the last four years as aConsulting Engineer. I have been involved in the preparation of proposals,designing and construction supervision of such projects. Therefore, I have used

my own knowledge and experience for this assignment.

C. REVIEW OF THE LITERATURE

Importance of the Dams in our Country

Pakistan is facing severe shortage of water for agriculture. Due to heavy sedimentinflows, all the three major storages (Tarbela, Mangla, Chashma) are alreadylosing their capacities. Therefore, there is urgent need not only to conserve thecapacity of existing storages but also to build new storage facilities for which thereis great potential. Pakistan is also energy deficient country and in desperate needfor additional generation of power.

With the passage of time, the available quantity of water will keep on decreasing.Only timely corrective measures could help mitigate the progressive loss incapacity due to natural phenomenon, otherwise, Pakistan would face severewater crisis. Therefore, to offset the increasing loss of existing water storagecapacity and to meet additional water requirements construction of severalstorages would be required.

By the year 2010 the three existing major storages would lose about6 MAF (7400 MCM) capacity which is 33% of their original capacity as given in

table below. This would virtually mean loss of one mega storage project. Thepresent storage capacity of the existing storages is only 11% of the total availablesurface water and there is a potential for development of 65 MAF (80,000 MCM)of storages, whereas on the average about 35 MAF (43,000 MCM) of waterescapes annually into sea. Part of the escapages need to be used for sustainableirrigated agriculture which supports about 70% of the population of Pakistan.


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Reservoir

Original

Gross Capacity

Capacity Loss (MAF)

2002 2010

(Projected)

Mangla 5.88 MAF (7,260 MCM) in 1967 1.16 (20%) 1.60 (27%)

Tarbela 11.62 MAF (14,340 MCM) in 1974 2.93 (25%) 3.95 (34%)

Chashma 0.87 MAF (1,070 MCM) in 1971 0.37 (43%) 0.48 (55%)

Total 18.37 MAF (22,670 MCM) 4.46 (24%) 6.03 (33%)

To save and utilize the available water, construction of additional storage facilitiesis essential. Pakistan Water and Power Development Authority (WAPDA) hasplanned a Water Resources and Hydropower Development Programme Vision -2025 .The programme is aimed to meet water and power demand, with the short term

(year 2001 to 2006 Phase-I), medium term (year 2006 to 2011 Phase-II) and longterm strategy (year 2011 onwards Phase-III). This programme on implementationwould provide additional storage and hydel power to the system, which isessentially required to cope with food and energy requirements of the increasingpopulation of Pakistan and to ultimately achieve sustained economicdevelopment.

Responsibilities of the Project Manager in any Project

A project manager is the person who has the overall responsibility for thesuccessful planning and execution of any project.

The project manager must possess a combination of skills including an ability toask penetrating questions, detect unstated assumptions, resolve interpersonalconflicts as well as more systematic management skills.

Key amongst his/her duties is the recognition that risk directly impacts thelikelihood of success and that this risk must be both formally and informallymeasured throughout the lifetime of the project.

Risk arises primarily from uncertainty and the successful project manager is theone who focuses upon this as the main concern. Most of the issues that impact a

project arise in one way or another from risk. A good project manager can reducerisk significantly, often by adhering to a policy of open communication, ensuringthat every significant participant has an opportunity to express opinions andconcerns.

It follows from the above that a project manager is one who is responsible formaking decisions both small and large, in such a way that risk is controlled and


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uncertainty minimised. Every decision taken by the project manager should betaken in such a way that it directly benefits the project.

The responsibilities of the Project Manager can be summarized as follows:

Leadership of the project teamEstablish a spirit of collaboration and teamwork.Using inputs from the team, express and communicate a vision for theteam.Assist the other members of the team in resolving problems.Keep the team focused on both weekly progress and the final objectives.Keep the team motivated.Help the individual members to make a contribution consistent with theirskill level and work style.Coordinates the activity of project room setup and keycollection/distribution with Glenn Molzer.Management of the project and team contributionsPrepare the project plan in collaboration with the team members.Establish the project schedule.Identify both formal and informal team roles for each member of the team.Schedule team meetings.Make certain the team meets the schedule for deliverables and taskmilestones.Make certain that the team conducts the peer reviews on schedule.Organize the team presentations: mid-term and end-of-term.Submits the team roles and a one page description of the project by theend of the 2 nd week of the semester to the MISM administration for theMISM website.Submits all deliverables including whitepaper, office supplies, projectbooks, etc to MISM administration on completion of project.Communications Routine, e.g. weekly, meetings with the advisors.Establish regular communications with the client.Organize visits to the client site, as needed.Ensure that team communications get to each team member

Impacts of Large Dams on Environment

Construction of large dams is not considered as environment friendly. They effectthe natural environment in many ways. Few of their effects on environment aregiven below:

By constructing huge structures and reservoirs, the stability of the strata is

disturbed due to unequal loading, which may be a cause of earthquake as

well.


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By diverting and stoppage of the natural stream, all fish and other aquatic

life in upstream is disturbed.

By restricting the flow of stream, consistent water flow in the downstream

areas is not available, which can effect the downstream Population in case

of a flood.

The Flora and Fauna in the downstream areas is affected.

Due to water storage in reservoir, the wildlife and biodiversity in the

periphery of the reservoir is affected and forced to migrate.

A large number of people is disturbed and have to be relocated due to the

reservoir. Verify often, people are not being paid as well. Example of

Mangla and Ghazi Barotha where most of the people have not been paid

their compensations.Relocation of the people has associated cultural and social loses as well.

The archeological and historical sites in area are also damaged.

A large number of trees are cutted during the construction and forests are

also lost in the reservoir.

During the construction activities, a noise and dust is created at all

locations.

Land inundation - creation of a reservoir will inundate frequently goodland. These factors lead to loss of productivity.

Beauty - areas of beauty will be destroyed.

Silt - retention of silt from the lower valley which would normally enrich the

land.

River Regime - a period of dry river bed below the dam will occur.

Effects of Storage on Quality of Water.

The Weather pattern of the area may also change as a result of such

human induced changes.


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D. THE STUDY

PART A: PREPARATION OF PROPOSAL FOR DAM

The proposal developed is based on the assumption that it is for a large dam andI am working as the Project Manager of Project Consultants. These settings maynot be valid for small dams where Consultants are not hired. The proposal for aDam Project will comprise of the following three parts:

1. Feasibility Stage.2. Design Stage3. Preparations of Tender Documents4. Construction of the Dam.

1. Feasibility StageDuring this stage of the project, all such studies will be carried out which arerequired to determine weather the project is feasible or not, both in terms offinancial as well as technical aspects.

These studies include:

Identification of the Available sources of water in the area (rivers,

streams). The available sources of water in the area will checked for the

quantity of water that may be available for the proposed project.Hydrological data of the streams with maximum and minimum flow and

weather pattern of the area will studied. The previous record of floods will

be collected and analyzed as well.

Identification and size of the catchment area for the reservoir will be

checked. The characteristics of the catchment area will also be studied in

detail.

Selection of Probable sites for Dam construction. Data will be collected for

all alternate sites for the dam construction. For this purpose,

reconnaissance and topographical surveys will also be carried out.

Potential size of the storage reservoir will also be determined depending

upon the quantity of water that may be available from stream flows and

natural precipitations.


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Identification of the potential areas for irrigation supplies. The areas which

will require irrigation supplies from the proposed dam and reservoir will be

determined.

Potential for Hydro Power Generation will be explored. The head available

for drop of water for hydro power generation will also be determined.

Preliminary geological investigations will be carried out to determine the

soil strata available at various depths.

Geotechnical Investigations will be carried out for identification of the soil

strata and its properties.

Identification of potential types of material to be used in construction.

Gradation envelopes for the required material to be used in the formation

of embankments will be developed.Identification of possible sources and queries for the materials to be used

at site. If any material is not available near to the site, the cost of importing

such material will also be determined.

Initial Assessment of the Possible Environmental Impacts of the Project.

Initial survey will also be carried out to determine the areas and number of

people to be dislocated from the construction of the dam.

Cost estimates for all Project Alternative sites will be developed. Theseestimates along with the technical aspects, will decide the selection of the

best suitable site for dam construction.

To calculate the EIRR (Economic Internal rate of Return) for all Project

Alternatives.

After carrying out all above mentioned studies, the project planning report

will be submitted to the Client.

2. Design Stage

During the detailed design stage of the project, the activities can be categorizedin following two classes.

1. Detailed Investigation Studies & Data Collection2. Analysis of collected data and the Design of Various Components.


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1. Detailed Investigation Studies & Data Collection

Following studies will be carried out to update the already done feasibility studiesof the Project.

Detailed Topographic studies of the identified site will be carried out todetermine the physical features of the area, elevations of all important

locations etc.

Hydrological data will be collected and analyzed. The maximum and

minimum flows in each season will be determined for the stream or river.

This will provide a good estimate of water available for storage in the

reservoir.

All probable alternate sites identified at the feasibility stage will be

analyzed for their technical advantages and disadvantages, their future

impacts and economic aspects (EIRR) and then Selection of the best site

for Dam and Reservoir will be made..

Detailed Geotechnical Investigations will be carried out for soil strata to

determine its various strength parameters (Internal friction angle,

coefficient of cohesion et).These parameters be used during the design of

foundations.

Geological Mapping of the site will be carried out. During this process, thesoil strata available at various depths below the natural ground will be

identified and their properties will also be determined.

Detailed surveys will be carried out for Selection of best suitable sites for

Spillways and Power House.

Detailed Investigations of the Potential Impacts on Environment and

preparation of Environmental Impact Assessment (EIA) Report. In the EIA

report, all potential impacts of the construction of the dam on environment

will be discussed and analyzed. At the end of the report, suitable

mitigation measures will also be proposed to minimize the potential

impacts of the dam on environment.

Detailed data collection for number of people effected from the

construction of dam and preparation of Resettlement Action Plan (RAP).


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This will include selection of probable sites where the people have to be

relocated and new colonies to be built.

2. Analysis of Data and Design of all Components

After analyzing the data collected in the first phase of design stage, the

following activities will be carried out.

Calculation of the dead and live loads for embankments and structures.

Design of foundations using high tech software.

The embankment in case of an earth dam consists of various zones. The

central zone being the impervious zone. Each zone is to be designed

individually to avoid any chances of seepage through the embankment.

Seepage & Slope stability analysis for embankments will be carried out.Analysis for factor of safety against overturning, shear and other potential

failures of the embankments.

Model Studies for Spillways and other important structures will be carried

out. Proto type models will be made for structures and they will be tested

under actual loading conditions to check the adequacy of design under

normal loading conditions.

Design of the Spillways structure and its foundation will be finalized aftermodel studies.

Design of Intake Structure and Tunnels will be carried out.

Design of Power house structure for maximum utilization of the head.

Design and selection of Turbines and other E & M components.

Design and selection of various instrumentation including the selection of

peizometers for taking the under ground water level readings.

Design of the infra structure facilities for all project staff.

3. Preparations of Tender Documents & BOQS

During this stage of the project, the following activities will be carried out.


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After the finalization of the design of all components of the projects,

Construction Drawings, Longitudinal Profiles, X-Sections will be prepared

for all components.

Bill of Quantities (BOQs) will be prepared (giving a reasonable estimate of

all project quantities) which will serve as a basis for competition among

the Contractors.

The estimated cost of the Project will be finalized.

Project Specifications will be finalized, which will contain, General

Conditions of the Contract, Technical Provisions and Special Provisions.

These are meant to ensure the quality of work during the construction

stage.

Tender will be floated in newspapers.All potential contenders will be short listed.

Based on previous experience, technical expertise, financial resources

and lowest rate offered, the Contractor will be finalized.

4. Construction of the Dam

During this stage, following activities will be carried out.

During this stage of the Project, the construction of the variouscomponents of the Project will be undertaken by the Contractor.

The Consultants team will ensure that all construction work is being

carried in strict accordance with the Project Specifications and relevant

Internal Standards (ACI, ASTM, AASHTO etc).

Design Review of the various components will be carried as and when

problems arise during the construction.

All efforts will be made for the timely completion of the project while

maintaining the quality of work.


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PART B: RESPONSIBILITIES OF THE PROJECT

MANAGER & SELECTION OF THE TEAM FOR

PROJECT:Responsibilities of Project Manager

Being the Project Manager for the Engineering Consultants of a Dam Project, Iwill be responsible for successful completion of the project within the stipulatedtime while maintaining the quality of work as required in project specifications. Inaddition to the responsibilities of the Project Manager mentioned in the LiteratureReview part of this report, my main responsibilities will be the following:

Selection of a well qualified, experienced, competent and dedicated team

for designing and construction supervision of the Project.

To supervise the selected team for all of their work and to provide

necessary guidance to them.

To collaborate with the Client and the Contractor for smooth running of the

Project.

To monitor the quality of works for various components of the Project.

To remain impartial and deal all issues with out any bias to both

Contractor and Client.

To help the Contractor in solving all site oriented problems for smoothrunning of the Project.

To conduct Progress review meetings with Client and Contractor for

solution of problems and monitoring of the progress.

Ensure that satisfactory working conditions / environment is provided to all

staff in the Field Office and at Site.

Selection of the TeamThe organization chart of my team is given at the end of this report as annexure

A. I will now describe the job description for few important members of myteam.

1. Head Design Section


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The responsibilities of the design head and his section has already beendiscussed in detail in the proposal section for the dam.

2. Head RAP & EIA Studies

He will be a key member of my team. His first responsibility wil be to determinethe impacts of the dam construction on environment and prepare theEnvironmental Impact Assessment Report.

The EIA report will contain the information about the legislation available in thecountry regarding the control of environmental degradation caused by theconstruction of large projects. It will also contain the national (Nationalenvironmental Quality Standards) and other relevant international standards forvarious emissions. These standards will serve as comparisons when the sitedata is collected.

The actual readings taken from site for various emissions and water quality areincluded and then compared with the standard values. If the actual values aregreater then the limits, suitable mitigation measures are proposed at the end ofreport for controlling these levels.

His second task will be to make various team for data collection regarding theareas effected from the construction of dam and the number of people to bedisturbed and their economic conditions. After conduction such survey, he willprepare and suggest compensation package for the effectees.

3. Head Health, Safety & Environment

The main responsibility of the Head HSE will be to ensure the safety of allpersons working in the project area. It includes both Consultants and Contractorsstaff. Following are the main functions of Head HSE:

Prepare check list for House Keeping and environmental condition of

contractor premises.

Issue Quarterly Schedule for Inspection.

Conduct Inspections/ follow-up inspections for House Keeping and

Environmental conditions of Contractor premises.

Prepare reports for discrepancies and distribute as required.

Conduct follow up inspections to ensure implementation of inspection results.


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Maintain Records.

He will achieve this object through the following approach:

Prepare Checklist for safety items & conduct the inspections

- General Items for work site / contractors staff housing compound.

- Safety & loss prevention Inspection (All-offices)

- Safety & loss prevention Inspection (All-Vehicles)

- Maintain Safety Record of individual contractor / JV components.

Issue schedules for Safety & Loss prevention inspections for work sites.

Conduct Safety & loss prevention inspections / meetings at site.

Produce Monthly and Quarterly reports on Safety & Loss prevention matters.

Develop and implement Safety & Loss Prevention procedures.

Inspect and verify Operators certificates and Drivers licenses.

Obtain reports from Contractors on Available Safety Equipments at site and

Residential compounds.

4. Chief Contracts & Claims

He will play a very important role first during the preparation of the TenderDocuments and specifications for the Project. Then during the award of the workto the Contractor, he will also play an effective and decisive role.

During the construction stage of the dam, he will deal all contractual issues andanalyze all claims submitted by the Contractor for any extra payments.

5. Chief Resident Engineer (construction Supervision)Chief Resident Engineer (CRE) will be directly responsible for monitoring theconstruction activities at site with help of his team members. His duties include:

Monitoring of works includes all Contracts for Project.


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Close coordination with Deputy Chief Resident Engineer (DCRE) and

Resident Engineer (REs) and support section Heads such as Survey,

Geology, Laboratory etc. backed by team of field/ office staff Scheduling,

Contracts, and Measurement & Claims.

To get updates from DCRE about activities in their respective sections and

to ensure timely response to all the correspondence / status of progress

submissions and to take appropriate actions and to resolve day to day

problems at the earliest.

Close coordination with the Project Manager, of each Contract and Design

Team for timely resolution of various design issues and design

modifications, clarifications of ambiguities in Contract document,construction drawings and intimation of such decisions to the Contractors.

Close coordination with Project Manager regarding progress monitoring

for timely completion of works in conformity with the Contract Documents.

Participation in the periodic meetings with the Employer and with the

Contractors, convened by the PM.

Participation in all internal meetings of Consultants called by the PM.

In the absence of PM or his other preoccupation, CRE is to perform his

duties.

Develop System for review and issuance of Construction drawings to the

Contractor.

Manage review and approval of shop drawings. Participate in preparation

of Project Completion Report.

Ensure that satisfactory working conditions / environment is provided to all

staff in the Field Office and at Site.

Deputy Chief Resident Engineer DCRE (construction

Supervision)


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Periodic meetings and liaison with REs of Consultant, PMs of Contractors

and their staff members to ensure that construction activities on the

projects are being executed in accordance with requirements of contract

documents.

Monitoring and review of contractors programme of works and its periodic

update.

Review of draft letters from all residencies and section heads before

sending to CRE.

Preparation of draft letters on important issues marked by PM for action.

Review of shop drawings and method statements before forwarding them

to CRE.

Liaison with Client for close coordination with construction supervisionteam.

Checking of contractors Monthly Statement and Interim Payment

Certificates prepared by measurement section.

Maintaining the status of daily correspondence and pursuance to relevant

sections for timely action on all matters.

Providing input to Chief Reports for Monthly, Quarterly and Yearly

Progress Reports. Liaison with Heads of Claim and Contract Sectionsregarding contractors claims, variation orders and other contractual

matters.

Provide assistance to PM and CRE in all aspects related to construction

supervision.

Head Quality Assurance & ControlScope of Work

Quality assurance and control section has been entrusted the responsibility forconducting the inspection of work in all stages of progress with a focus on qualityassurance for all activities of Civil, Mechanical and Electrical jobs which arebeing executed under different contracts for Project with the assistance of theConsultants site staff. Through series of planned actions i.e. inspections, tests,observations it will be ensured that intent of design and specifications isimplemented and process of product identification and traceability was completed


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for every major item. This function may be extended to the other disciplines ofthe project in due course of time and subject to availability of required resources.Devolvement of Quality Assurance Plan

The quality assurance shall include:-

1. A list of all items that are subject to quality assurance.

2. The required special inspection and testing.

3. The type and frequency of special inspection.

4. The frequency and distribution of testing and special inspection reports.

5. The structural observation to be performed.

6. The frequency and distribution of observation reports.

7. The inspection schedules and reports.8. Internal Quality Audits and reports.

9. Recording of Non-Compliance by contractor and generation of reports.

Functions of the Head Quality Assurance

1. Acknowledgment of awareness of the requirements contained in the qualityassurance plan.

2. Acknowledgment that control will be exercised to obtain conformance withthe construction documents.

3. Production of procedures for exercising control within QA&C sectionorganization, the method and frequency of reporting, and distribution ofreports.

4. Identification and qualification of the persons exercising such control andtheir position in the organization i.e. job descriptions of the QA&C sectionstaff.

PREVENTIVE ACTION REQUIREMENT (PAR)

Preventive actions are identified to eliminate the causes of potential non-compliance in order to prevent their occurrences, employees of Consultants canreport problems requiring prevention with regard to quality specifications,procedures, product, services, safety & loss prevention, etc to QA&C sectionwhich will coordinate for the solution. General Focus of QA&C section will beencompassing the entire activities of the Project, specifically the constructionworks being under taken by different Contractors. Therefore, discrepanciesrevealed during inspection/or reported otherwise will be conveyed under theheading of PAR (Preventive Action Required) to the respective Contractors. A


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ceaseless effort shall be made by QA&C section for follow up ensuring therectification process completion.

CORRECTIVE ACTION REQUIREMENT (CAR)

Corrective actions are essential to alleviate the causes of non-conformities inorder to prevent their recurrences. If any item identified & reported under PAR(Preventive Action Requirement) is not rectified then the CAR will be initiated,which is a stronger & severe form for highlighting discrepancies.

The CAR process will be utilized to convey to The Client and The Engineer aboutslackness on the part of Contractors in implementing the rectification works forthe discrepancies indicated through PAR-system. The Quality Control Section ofall operating contractors will be responsible for providing feedback about therectification work to the QA&C section.

Conduct short courses for Consultants Staff on QUALITY ASSURANCE AND

CONTROL with emphasize on Project Management.

Functions of Individual Resident Engineers (REs)

All individual section heads (RE Embankments, RE Spillways, REInstrumentation, RE Infrastructure, RE Mechanical & Electrical Works, REPowerhouse, Head Geology, Head Survey, Chief Planning & Measurements etc)will ensure the quality of works undertaken by the Contractor in their residenciesas per quality assurance plan of the project.

DamFrom Wikipedia, the free encyclopedia

This article is about structures for water impoundment. For other uses, see Dam (disambiguation) .
http://en.wikipedia.org/wiki/Dam_(disambiguation)http://en.wikipedia.org/wiki/Dam_(disambiguation)http://en.wikipedia.org/wiki/Dam_(disambiguation)http://en.wikipedia.org/wiki/Dam_(disambiguation)


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Hoover Dam , a concrete arch-gravity dam in Black Canyon of the Colorado River . Lake Mead in the background

is impounded by the dam.

Glen Canyon Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary

purpose of retaining water, while other structures such as floodgates or levees (also known as dikes )

are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage

hydroelectricity are often used in conjunction with dams to generate electricity. A dam can also be

used to collect water or for storage of water which can be evenly distributed between locations.
http://en.wikipedia.org/wiki/Hoover_Damhttp://en.wikipedia.org/wiki/Hoover_Damhttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Black_Canyon_of_the_Coloradohttp://en.wikipedia.org/wiki/Black_Canyon_of_the_Coloradohttp://en.wikipedia.org/wiki/Black_Canyon_of_the_Coloradohttp://en.wikipedia.org/wiki/Lake_Meadhttp://en.wikipedia.org/wiki/Lake_Meadhttp://en.wikipedia.org/wiki/Lake_Meadhttp://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Glen_Canyon_Damhttp://en.wikipedia.org/wiki/Glen_Canyon_Damhttp://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Surface_waterhttp://en.wikipedia.org/wiki/Surface_waterhttp://en.wikipedia.org/wiki/Surface_waterhttp://en.wikipedia.org/wiki/Floodgateshttp://en.wikipedia.org/wiki/Floodgateshttp://en.wikipedia.org/wiki/Floodgateshttp://en.wikipedia.org/wiki/Leveehttp://en.wikipedia.org/wiki/Leveehttp://en.wikipedia.org/wiki/Leveehttp://en.wikipedia.org/wiki/Dike_(construction)http://en.wikipedia.org/wiki/Dike_(construction)http://en.wikipedia.org/wiki/Dike_(construction)http://en.wikipedia.org/wiki/Hydropowerhttp://en.wikipedia.org/wiki/Hydropowerhttp://en.wikipedia.org/wiki/Hydropowerhttp://en.wikipedia.org/wiki/Pumped-storage_hydroelectricityhttp://en.wikipedia.org/wiki/Pumped-storage_hydroelectricityhttp://en.wikipedia.org/wiki/Pumped-storage_hydroelectricityhttp://en.wikipedia.org/wiki/Pumped-storage_hydroelectricityhttp://en.wikipedia.org/wiki/File:Glen_canyon_dam.jpghttp://en.wikipedia.org/wiki/File:Glen_canyon_dam.jpghttp://en.wikipedia.org/wiki/File:Hoover_Dam_Nevada_Luftaufnahme.jpghttp://en.wikipedia.org/wiki/File:Hoover_Dam_Nevada_Luftaufnahme.jpghttp://en.wikipedia.org/wiki/File:Glen_canyon_dam.jpghttp://en.wikipedia.org/wiki/File:Glen_canyon_dam.jpghttp://en.wikipedia.org/wiki/File:Hoover_Dam_Nevada_Luftaufnahme.jpghttp://en.wikipedia.org/wiki/File:Hoover_Dam_Nevada_Luftaufnahme.jpghttp://en.wikipedia.org/wiki/File:Glen_canyon_dam.jpghttp://en.wikipedia.org/wiki/File:Glen_canyon_dam.jpghttp://en.wikipedia.org/wiki/File:Hoover_Dam_Nevada_Luftaufnahme.jpghttp://en.wikipedia.org/wiki/File:Hoover_Dam_Nevada_Luftaufnahme.jpghttp://en.wikipedia.org/wiki/File:Glen_canyon_dam.jpghttp://en.wikipedia.org/wiki/File:Glen_canyon_dam.jpghttp://en.wikipedia.org/wiki/File:Hoover_Dam_Nevada_Luftaufnahme.jpghttp://en.wikipedia.org/wiki/File:Hoover_Dam_Nevada_Luftaufnahme.jpghttp://en.wikipedia.org/wiki/Pumped-storage_hydroelectricityhttp://en.wikipedia.org/wiki/Pumped-storage_hydroelectricityhttp://en.wikipedia.org/wiki/Hydropowerhttp://en.wikipedia.org/wiki/Dike_(construction)http://en.wikipedia.org/wiki/Leveehttp://en.wikipedia.org/wiki/Floodgateshttp://en.wikipedia.org/wiki/Surface_waterhttp://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Glen_Canyon_Damhttp://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Lake_Meadhttp://en.wikipedia.org/wiki/Black_Canyon_of_the_Coloradohttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Hoover_Dam


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4 Dam creation

o 4.1 Common purposes

o 4.2 Location

o

4.3 Impact assessment 4.3.1 Environmental impact

4.3.2 Human social impact

4.3.3 Economics

5 Dam failure

6 See also

7 References

8 Sources

9 External links

[ edit ] History

The Roman dam at Cornalvo in Spain has been in use for almost two millennia.

Grand Anicut dam on river Kaveri in Tamil Nadu , South India (19th century on 1st-2nd century foundation)

The word dam can be traced back to Middle English ,[1] and before that, from Middle Dutch , as seen in

the names of many old cities .[2] Early dam building took place in Mesopotamia and the Middle East .
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Dams were used to control the water level, for Mesopotamia's weather affected

the Tigris and Euphrates rivers, and could be quite unpredictable.

The earliest known dam is the Jawa Dam in Jordan , 100 kilometres (62 mi) northeast of the

capital Amman . This gravity dam featured a 4.5 m (15 ft) high and 1 m (3 ft 3 in) wide stone wall,

supported by a 50 m (160 ft) wide earth rampart. The structure is dated to 3000 BC .[3][4] The Ancient

Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, located about 25 km (16 mi) south of Cairo , was

102 m (335 ft) long at its base and 87 m (285 ft) wide. The structure was built around 2800 [5] or 2600

B.C .[6] as a diversion dam for flood control, but was destroyed by heavy rain during construction or

shortly afterwards .[5][6] By the mid-late third century BC, an intricate water-management system

withinDholavira in modern day India, was built. The system included 16 reservoirs, dams and various

channels for collecting water and storing it .[7]

Roman dam construction was characterized by "the Romans' ability to plan and organize engineering

construction on a grand scale" .[8] Roman planners introduced the then novel concept of large reservoir

dams which could secure a permanent water supply for urban settlements also over the dry

season .[9]Their pioneering use of water-proof hydraulic mortar and particularly Roman

concrete allowed for much larger dam structures than previously built ,[8] such as the Lake Homs Dam ,

possibly the largest water barrier to that date ,[10] and the Harbaqa Dam , both in Roman Syria . The

highest Roman dam was the Subiaco Dam near Rome ; its record height of 50 m (160 ft) remained

unsurpassed until its accidental destruction in 1305 .[11]

Roman engineers made routine use of ancient standard designs like embankment dams and masonry

gravity dams .[12] Apart from that, they displayed a high degree of inventiveness, introducing most of the

other basic dam designs which had been unknown until then. These include arch-gravity dams ,[13] arch

dams ,[14] buttress dams [15] and multiple arch buttress dams ,[16] all of which were known and employed

by the 2nd century AD (see List of Roman dams ). Roman workforces also were the first to build dam

bridges, such as th e Bridge of Valerian in Iran .[17]

Eflatun Pnar is a Hittite dam and spring temple near Konya, Turkey. It's thought to be from the time of

the Hittite empire between the 15th and 13 century BC.

The Kallanai is constructed of unhewn stone, over 300 m (980 ft) long, 4.5 m (15 ft) high and 20 m

(66 ft) wide, across the main stream of the Kaveri river in Tamil Nadu , South India . The basic structure

dates to the 2nd century AD [18] and is considered one of the oldest water-diversion or water-regulator

structures in the world, which is still in use .[19] The purpose of the dam was to divert the waters of the

Kaveri across the fertile Delta region for irrigation via canals .[20]

Du Jiang Yan is the oldest surviving irrigation system in China that included a dam that directed

waterflow. It was finished in 251 B.C. A large earthen dam, made by the Prime Minister of Chu
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(state) , Sunshu Ao , flooded a valley in modern-day northern Anhui province that created an

enormous irrigation reservoir 100 km (62 mi) in circumference), a reservoir that is still present today .[21]

In Iran , bridge dams such as the Band-e Kaisar were used to provide hydropower through water

wheels , which often powered water-raising mechanisms. One of the first was the Roman-built dam

bridge in Dezful ,[22] which could raise water 50 cubits in height for th e water supply to all houses in the

town. Also diversion dams were known .[23] Milling dams were introduced which the Muslim

engineers called the Pul-i-Bulaiti . The first was built at Shustar on the River Karun , Iran , and many of

these were later built in other parts of th e Islamic world .[23] Water was conducted from the back of the

dam through a large pipe to drive a water wheel and watermill .[24] In the 10th century, Al-

Muqaddasi described several dams in Persia. He reported that one in Ahwaz was more than 910 m

(3,000 ft) long ,[25]and that and it had many water-wheels raising the water into aqueducts through

which it flowed into reservoirs of the city .[26] Another one, the Band-i-Amir dam, provided irrigation for

300 villages .[25]

In the Netherlands , a low-lying country, dams were often applied to block rivers in order to regulate the

water level and to prevent the sea from entering the marsh lands. Such dams often marked the

beginning of a town or city because it was easy to cross the river at such a place, and often gave rise

to the respective place's names in Dutch. For instance the Dutch capital Amsterdam (old name

Amstelredam) started with a dam through the river Amstel in the late 12th century,

and Rotterdam started with a dam through the river Rotte, a minor tributary of the Nieuwe Maas . The

central square of Amsterdam, covering the original place of the 800 year old dam, still carries the

name Dam Square or simply the Dam .

French engineer Benot Fourneyron developed the first successful water turbine in 1832. The era of

large dams was initiated after Hoover Dam was completed on the Colorado River near Las Vegas in

1936. By 1997, there were an estimated 800,000 dams worldwide, some 40,000 of them over 15 m

(49 ft) high .[27]

[ edit ] Types of dams

Dams can be formed by human agency, natural causes, or even by the intervention of wildlife such

as beavers . Man-made dams are typically classified according to their size (height), intended purpose

or structure.

[edit ]By structure

Based on structure and material used, dams are classified as timber dams, arch-gravity

dams , embankment dams or masonry dams , with several subtypes.

[edit ]Arch dams
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rado_Riverhttp://en.wikipedia.org/wiki/Dam#cite_note-26http://en.wikipedia.org/wiki/Dam#cite_note-26http://en.wikipedia.org/wiki/Dam#cite_note-26http://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=2http://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=2http://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=2http://en.wikipedia.org/wiki/Beaverhttp://en.wikipedia.org/wiki/Beaverhttp://en.wikipedia.org/wiki/Beaverhttp://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=3http://en.wikipedia.org/wiki/Timberhttp://en.wikipedia.org/wiki/Timberhttp://en.wikipedia.org/wiki/Timberhttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Embankment_damhttp://en.wikipedia.org/wiki/Embankment_damhttp://en.wikipedia.org/wiki/Embankment_damhttp://en.wikipedia.org/wiki/Masonry_damhttp://en.wikipedia.org/wiki/Masonry_damhttp://en.wikipedia.org/wiki/Masonry_damhttp://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=4http://en.wikipedia.org/wiki/Masonry_damhttp://en.wikipedia.org/wiki/Embankment_damhttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Arch-gravity_damhttp://en.wikipedia.org/wiki/Timberhttp://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=3http://en.wikipedia.org/wiki/Beaverhttp://en.wikipedia.org/w/index.php?title=Dam&action=edit&section=2http://en.wikipedia.org/wiki/Dam#cite_note-26http://en.wikipedia.org/wiki/Colorado_Riverhttp://en.wikipedia.org/wiki/Hoover_Damhttp://en.wikipedia.org/wiki/Water_turbinehttp://en.wikipedia.org/wiki/Beno%C3%AEt_Fourneyronhttp://en.wikipedia.org/wiki/Dam_Squarehttp://en.wikipedia.org/wiki/Nieuwe_Maashttp://en.wikipedia.org/wiki/Rotterdamhttp://en.wikipedia.org/wiki/Amstelhttp://en.wikipedia.org/wiki/Amsterdamhttp://en.wikipedia.org/wiki/Netherlandshttp://en.wikipedia.org/wiki/Dam#cite_note-Hill-56-8-24http://en.wikipedia.org/wiki/Dam#cite_note-Hill-31-25http://en.wikipedia.org/wiki/Reservoirhttp://en.wikipedia.org/wiki/Aqueducthttp://en.wikipedia.org/wiki/Dam#cite_note-Hill-56-8-24http://en.wikipedia.org/wiki/Ahvazhttp://en.wikipedia.org/wiki/Al-Muqaddasihttp://en.wikipedia.org/wiki/Al-Muqaddasihttp://en.wikipedia.org/wiki/Dam#cite_note-Lucas-23http://en.wikipedia.org/wiki/Watermillhttp://en.wikipedia.org/wiki/Dam#cite_note-Hill-Engineering-22http://en.wikipedia.org/wiki/Islamic_worldhttp://en.wikipedia.org/wiki/Iranhttp://en.wikipedia.org/wiki/Karunhttp://en.wikipedia.org/wiki/Muslim_Agricultural_Revolutionhttp://en.wikipedia.org/wiki/Muslim_Agricultural_Revolutionhttp://en.wikipedia.org/wiki/Mill_(grinding)http://en.wikipedia.org/wiki/Dam#cite_note-Hill-Engineering-22http://en.wikipedia.org/wiki/Diversion_damhttp://en.wikipedia.org/wiki/Water_supplyhttp://en.wikipedia.org/wiki/Cubithttp://en.wikipedia.org/wiki/Dam#cite_note-21http://en.wikipedia.org/wiki/Dezfulhttp://en.wikipedia.org/wiki/Water_wheelhttp://en.wikipedia.org/wiki/Water_wheelhttp://en.wikipedia.org/wiki/Hydropowerhttp://en.wikipedia.org/wiki/Band-e_Kaisarhttp://en.wikipedia.org/wiki/Iranhttp://en.wikipedia.org/wiki/Dam#cite_note-needham_volume_4_part_3_271-20http://en.wikipedia.org/wiki/Irrigationhttp://en.wikipedia.org/wiki/Anhuihttp://en.wikipedia.org/wiki/Sunshu_Aohttp://en.wikipedia.org/wiki/Chu_(state)


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Gordon Dam , Tasmania is an arch dam .

Main article: Arch dam

In the arch dam, stability is obtained by a combination of arch and gravity action. If the upstream face

is vertical the entire weight of the dam must be carried to the foundation by gravity, while the

distribution of the normal hydrostatic pressure between vertical cantilever a nd arch action will depend

upon the stiffness of the dam in a vertical and horizontal direction. When the upstream face is sloped

the distribution is more complicated. The normal component of the weight of the arch ring may be taken

by the arch action, while the normal hydrostatic pressure will be distributed as described above. For

this type of dam, firm reliable supports at the abutments (either buttress or canyon side wall) are more

important. The most desirable place for an arch dam is a narrow canyon with steep side walls

composed of sound rock .[28] The safety of an arch dam is dependent on the strength of the side wall

abutments, hence not only should the arch be well seated on the side walls but also the character of

the rock should be carefully inspected.
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Daniel-Johnson Dam , Quebec , is a multiple-arch buttress dam.

Two types of single-arch dams are in use, namely the constant-angle and the constant-radius dam.

The constant-radius type employs the same face radius at all elevations of the dam, which means that

as the channel grows narrower towards the bottom of the dam the central angle subtended by the face

of the dam becomes smaller. Jones Falls Dam , in Canada, is a constant radius dam. In a constant-

angle dam, also known as a variable radius dam, this subtended angle is kept a constant and the

variation in distance between the abutments at various levels are taken care of by varying the radii.

Constant-radius dams are much less common than constant-angle dams. Parker Dam is a constant-

angle arch dam.

A similar type is the double-curvature or thin-shell dam. Wildhorse Dam near Mountain City, Nevada in

the United States is an example of the type. This method of construction minimizes the amount of

concrete necessary for construction but transmits large loads to the foundation and abutments. The

appearance is similar to a single-arch dam but with a distinct vertical curvature to it as well lending it

the vague appearance of a concave lens as viewed from downstream.

The multiple-arch dam consists of a number of single-arch dams with concrete buttresses as the

supporting abutments, as for example the Daniel-Johnson Dam , Qubec, Canada. The multiple-arch

dam does not require as many buttresses as the hollow gravity type, but requires good rock foundation

because the buttress loads are heavy.

[edit ]Gravity dams

This unreferenced section

requires citations to

ensur everifiability .

The Grand Coulee Dam is an example of a solid gravity dam.

In a gravity dam, the force that holds the dam in place against the push from the water is Earth's

gravity pulling down on the mass of the dam .[29] The water presses laterally (downstream) on the dam,

tending to overturn the dam by rotating about its toe (a point at the bottom downstream side of the
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dam). The dam's weight counteracts that force, tending to rotate the dam the other way about its toe.

The designer ensures that the dam is heavy enough that gravity wins that contest. In engineering

terms, that is true whenever the resultant of the forces of gravity and water pressure on the dam acts

in a line that passes upstream of the toe of the dam.

Furthermore, the designer tries to shape the dam so if one were to consider the part of dam above any

particular height to be a whole dam itself, that dam also would be held in place by gravity. i.e. there is

no tension in the upstream face of the dam holding the top of the dam down. The designer does this

because it is usually more practical to make a dam of material essentially just piled up than to make

the material stick together against vertical tension.

Note that the shape that prevents tension in the upstream face also eliminates a balancing

compression stress in the downstream face, providing additional economy.

The designer also ensures that the toe of the dam is sunk deep enough in the earth that it does notslide forward.

For this type of dam, it is essential to have an impervious foundation with high bearing strength.

When situated on a suitable site, a gravity dam can prove to be a better alternative to other types of

dams. When built on a carefully studied foundation, the gravity dam probably represents the best

developed example of dam building. Since the fear of flood is a strong motivator in many regions,

gravity dams are being built in some instances where an arch dam would have been more economical.

Gravity dams are classified as "solid" or "hollow" and are generally made of either concrete or

masonry. This is called "zoning". The core of the dam is zoned depending on the availability of locally

available materials, foundation conditions and the material attributes. The solid form is the more widely

used of the two, though the hollow dam is frequently more economical to construct. Gravity dams can

also be classified as "overflow" (spillway) and "non-overflow." Grand Coulee Dam is a solid gravity

dam and Itaipu Dam is a hollow gravity dam.

Arch-gravity dams
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The Hoover Dam is an example of an arch-gravity dam.

Main article: Arch-gravity dam

This section requires expansion .

A gravity dam can be combined with an arch dam into an arch-gravity dam for areas with massiveamounts of water flow but less material available for a purely gravity dam.

[edit ]Barrages

The Koshi Barrage

Main article: Barrage dams

A barrage dam is a special kind of dam which consists of a line of large gates that can be openedor closed to control the amount of water passing the dam. The gates are set between flankingpiers which are responsible for supporting the water load. They are often used to control andstabilize water flow for irrigation systems.

Barrages that are built at the mouth of rivers or lagoons to prevent tidal incursions or utilize the

tidal flow for tidal power are known as tidal barrages .[30]

[edit ]Embankment dams

Main article: Embankment dam

Embankment dams are made from compacted earth, and have two main types, rock-fill andearth-fill dams. Embankment dams rely on their weight to hold back the force of water, like thegravity dams made from concrete.

[edit ]Rock-fill dams

The Gathright Dam in Virginia is a rock-fi llembankment dam .
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Rock -fill dams are embankments of compacted free-draining granular earth with an imperviouszone. The earth utilized often contains a large percentage of large particles hence the term rock- fill . The impervious zone may be on the upstream face and made of masonry ,concrete , plasticmembrane, steel sheet piles, timber or other material. The impervious zone may also be withinthe embankment in which case it is referred to as a core . In the instances where clay is utilized as

the impervious material the dam is referred to as a composite dam. To prevent internal erosion ofclay into the rock fill due to seepage forces, the core is separated using a filter. Filters arespecifically graded soil designed to prevent the migration of fine grain soil particles. Whensuitable material is at hand, transportation is minimized leading to cost savings duringconstruction. Rock-fill dams are resistant to damage from earthquakes . However, inadequatequality control during construction can lead to poor compaction and sand in the embankmentwhich can lead to liquefaction of the rock-fill during an earthquake. Liquefaction potential can bereduced by keeping susceptible material from being saturated, and by providing adequatecompaction during construction. An example of a rock-fill dam is New Melones Dam in California .

[edit ]Concrete-face rock-fill dams

A concrete-face rock-fill dam (CFRD) is a rock-fill dam with concrete slabs on its upstream face.This design offers the concrete slab as an impervious wall to prevent leakage and also a structurewithout concern for uplift pressure. In addition, the CFRD design is flexible for topography, fasterto construct and less costly than earth-fill dams. The CFRD originated during the California GoldRush in the 1860s when miners constructed rock-fill timber-face dams for sluice operations . Thetimber was later replaced by concrete as the design was applied to irrigation and power schemes.As CFRD designs grew in height during the 1960s, the fill was compacted and the slab'shorizontal and vertical joints were replaced with improved vertical joints. In the last few decades,the design has become popular .[31]Currently, the tallest CFRD in the world is the 233 m (764 ft)tall Shuibuya Dam in China which was completed in 2008 .[32]

[edit ]Earth-fill dams Earth-fill dams , also called earthen dams , rolled-earth dams or simply earth dams , areconstructed as a simple embankment of well compacted earth. A homogeneous rolled-earth damis entirely constructed of one type of material but may contain a drain layer to collect seep water.A zoned-earth dam has distinct parts or zones of dissimilar material, typically a locallyplentiful shell with a watertight clay core. Modern zoned-earth embankments employ filter anddrain zones to collect and remove seep water and preserve the integrity of the downstream shellzone. An outdated method of zoned earth dam construction utilized a hydraulic fill to produce awatertight core. Rolled-earth dams may also employ a watertight facing or core in the manner of arock-fill dam. An interesting type of temporary earth dam occasionally used in high latitudes isthe frozen-core dam, in which a coolant is circulated through pipes inside the dam to maintain awatertight region of permafrost within it.

Tarbela Dam is a large dam on the Indus River in Pakistan . It is located about 50 km (31 mi)northwest of Islamabad, and a height of 485 ft (148 m) above the river bed and a reservoir size of95 sq mi (250 km 2) makes it the largest earth filled dam in the world. The principal element of theproject is an embankment 9,000 feet (2,700 metres) long with a maximum height of 465 feet (142metres). The total volume of earth and rock used for the project is approximately 200 million cubic
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