My name is Bucky Beaver, and I want to tell you all about my favorite subject, DAMS! Although the dams I build are for my protection and are small, I know a lot about human dams!
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Dams help control water, our most important resource. Water is important because plants, animals and humans need to drink it to stay alive. We also use it to cook, clean and bathe. We also use water to have fun. What fun would a swimming pool be without water?
It is important that we have just the right amount of water. Having too much water will cause a flood. Having too little will cause a drought. We need a way to have just the right amount.
Building a dam can help control the flow of water and the amount of water that we have available!
Dams are built on rivers so that the water in the river can be controlled. When a dam is built, it creates a reservoir of water, also called man-made lakes. Dams help us store water when we need it and help prevent droughts and floods. When too much water is in a reservoir, it can be released safety through gates.
They can be built from many different materials, including earth, rock, tailings from mining or milling, concrete, masonry, steel, timber, miscellaneous materials (such as plastic or rubber) and any combination of these materials. The material that is used depends on how the dam is going to be used.
Some dams are used for water supply, others for energy for a town or even for recreation. Some are used to prevent flooding. It is up to the engineer to know what the dam is being used for and choose the best design.
CREST - the top of a dam
ABUTMENT - the part of the valley side that meets the dam
BERM - a nearly horizontal step in the sloping profile of an embankment dam
OUTLET - an opening where water can be released
SPILLWAY - a structure that allows water to be released from a reservoir
EMERGENCY SPILLWAY - An extra spillway
People started building dams a very long time ago. The ancient Egyptians built simple dams of earth and stones to store water from the Nile River well over years ago! Dams were also built in ancient times in Mesopotamia (now Iraq), Italy, and India. These early dams were built mostly of stone, earth, and gravel and were used to water crops.
Many dam builders then learned from people before them and continued to pass along the practice. Once modern engineering came along, the size and abilities of dams improved.
Dam engineering is still improving today. Below are some old pictures of dams in the United States. Thanks to the help of very smart engineers, the dams we build today are bigger, stronger and safer than these dams!
Did you know there are more than 90,000 dams in the United States alone? This map shows where the dams are located.
Humans use dams for a lot of reasons! Millions of people depend on dams to help provide the right amount of water in the right place at the right time.
Most dams do more than one job! We fish, swim and boat on about 1 in every three lakes formed by dams. Lots of dams provide water for growing crops and for farm animals to drink. They also store water for fighting fires and can help control floods.
Dams also give us hydroelectric power! U.S. dams provide almost 10% of the nation's power needs. Hydropower is a renewable source of electricity that is friendly to the environment. It does not contribute to global warming, air pollution, acid rain or ozone depletion.
Although the water around dams may look peaceful and fun, it is very dangerous!!
Don't ever play near a dam! Even if you aren't in the water, you could slip and fall in. This doesn't mean just big dams. Even small ones can be very dangerous!
You should always have a parent with you when you are near a dam!
Don't just take my word for it! Put on your work clothes and build a dam. Here are some instructions, but you'll probably have ideas of your own, too!
Easy Version - Instructions
Hard Version - Instructions
The humans at PBS made a game that lets players pretend to be a real dam engineer! It's fun - try it now!
Click here!
For other PBS resources click here!
Then sit down, grab a pencil and some crayons, and try these activities!
Crossword
Maze
Activity Book (Low-Head Dams)
The broad definition of a dam is provided in the Code of Maryland Regulations (COMAR) 26.17.04.02 as any obstruction, wall, or embankment, together with its abutments and appurtenant works, if any, in, along, or across any stream, heretofore or hereafter constructed for the purpose of storing or diverting water or for creating a pool upstream of the dam, as determined by the Administration.
There are no natural lakes or ponds in Maryland, therefore nearly all bodies of water in the State are formed by dams. Note that the Maryland Department of the Environment’s (MDE or Department) Dam Safety program does not regulate water bodies formed by beaver dams or coastal erosion/deposition. Abandoned mines/quarries may also create water bodies, and may be regulated by the Dam Safety program if a dam is constructed to control water levels or discharges.
Certain smaller dams, commonly called small ponds, are not assigned a Maryland Dam ID Number, are not included in the Maryland Dam Inventory, and are inspected by MDE Dam Safety staff on an as-requested basis. These small ponds are typically found in agriculture or in smaller scale stormwater management practices.
Persons wishing to construct, reconstruct, modify, remove or repair these small ponds may be able to obtain approval from the local Soil Conservation District, or MDE’s designee, providing the following criteria are met:
If you are looking for more details, kindly visit small dam spillway design.
Note that these small ponds located in the watersheds of the Jones Falls, Gwynns Falls, or Herring Run streams in or adjacent to Baltimore City require permits for construction, reconstruction or alteration to be issued by the MDE Dam Safety Permits Division.
While the specific laws and regulations have evolved over time, the regulation of dams and reservoirs, of which, “small ponds” is a sub-category, has remained at the State level since . This is codified in the Code of Maryland, Environment Article, §5–501 through 5-514. MDE is responsible under Maryland law to adequately preserve public safety, and promote the general public welfare by implementing a comprehensive Dam Safety program. MDE has promulgated regulations to implement comprehensive Waterway Construction and Dam Safety programs based on the powers authorized in the law cited above. These regulations are located in COMAR 26.17.04, which concerns Construction on Non-Tidal Waters and Floodplains. Additional regulations within this subtitle specific to dams are found in 26.17.04.05.
Review and approval for construction of certain small ponds can be performed by the local SCD and/or the MDE designee as discussed in the ‘What is a Small Pond” question.
Adapted from FEMA 333: Hazard Potential Classification System for Dams. The hazard potential classification system for dams is based on the probable loss of human life and the potential for economic losses, environmental damage, and/or disruption to lifelines caused by failure or mis-operation of a dam or its appurtenances. The hazard potential classification assigned to a dam is based on consideration of the effects of a failure or mis-operation during both normal and flood flow conditions. The classification should be based on the worst-case probable scenario of failure or mis-operation of the dam. A primary purpose of any classification system is to select appropriate design criteria. In other words, design criteria will become more conservative as the potential for loss of life and/or property damage increases.
Three classification levels are adopted as follows: LOW, SIGNIFICANT, and HIGH, listed in order of increasing adverse consequences. This hazard potential classification system should be utilized with the understanding that the failure of any dam or water-retaining structure, no matter how small, could represent a danger to downstream life and property.
LOW HAZARD POTENTIAL Dams assigned the low hazard potential classification are those where loss of human life due to failure or mis-operation is unlikely and results in low economic and/or environmental losses. Losses are principally limited to the dam owner’s property.
SIGNIFICANT HAZARD POTENTIAL Dams assigned the significant hazard potential classification are those dams where there is a small possibility of loss of life due to failure or mis-operation but can cause economic loss, environmental damage, disruption of lifeline facilities, or can impact other concerns.
HIGH HAZARD POTENTIAL Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life, serious damage to structures, important roads, public utilities or railroads.
Hazard classification categories, low, significant and high are synonymous with Natural Resources Conservation Service (NRCS) Pond Code MD-378 hazard classes “a”, “b”, and “c”, respectively.
Anyone planning to construct, reconstruct, repair or alter a dam or reservoir in the State of Maryland must receive a permit from MDE Dam Safety or, if the structure qualifies as a small pond, approval by the local SCD or MDE designee. Note that this regulatory requirement includes construction and alteration of the “reservoir” as well, thus work that is planned within the impounded area requires review and approval even if the dam embankment is not directly altered.
Normal maintenance activities at dams, reservoirs and their appurtenant works is encouraged and demonstrates responsible ownership of said structures. Accordingly, certain maintenance activities are considered exempt from the requirement to obtain a permit. These activities are defined in Dam Safety Policy Memorandum #11 – Activities Not Requiring a Dam Safety Permit.
Small pond approval does not relieve the applicant from the requirement of obtaining any other necessary local, State or U.S. Army Corps of Engineers permits. This may include, but is not limited to, erosion and sediment control approvals, grading approvals, and MDE Non-Tidal Wetlands and Waterways Division approvals.
Complete a "Joint Federal/State Application for the Alteration of any Floodplain, Waterway, Tidal or Nontidal Wetland in Maryland" application, as well as Appendix B for Dams and Small Ponds. Note that all owners of the dam must sign the application, even if the work is proposed on only a single parcel.
The application must be mailed with the original plus six copies of the application, plans, vicinity maps, and any supporting documentation to: Regulatory Services Coordination Office (RSC) MDE, Water and Science Administration, Washington Boulevard Baltimore, Maryland .
Application materials that are specific to Dam Safety review (e.g., breach analysis, inundation mapping, basis of design reports) can be emailed to [ protected], or to the assigned reviewer, if known.
Prior to submitting your application, it is suggested that you or your engineer contact the Dam Safety Permits Division to discuss the documentation necessary for your submittal and any unique project elements and applicable design requirements.
A permit application to construct, reconstruct, repair or alter a dam must be prepared by a registered professional engineer, practicing in accordance with the laws of Maryland and qualified in the field of dam design and construction.
This engineer, deemed the engineer-in-charge (EIC) must oversee the preparation of the designs and specifications and provide supervision during construction of the proposed works. The EIC is responsible for assuring that the designs conform to the high standards of professional competence in the specialty of dam design and construction, and assures that the construction is carried out in strict accordance with the approved plans and specifications and under the provisions of the permit.
The EIC must submit an affidavit attesting to their qualifications, and must submit a resume of all previous dam design and construction experience, listing specific responsibilities. It is important that the EIC have demonstrated experience working with dams of a similar age, construction method, and hazard potential as the proposed project.
Just because a dam has been in service for a long time does not mean it cannot develop a problem. As dams age, individual components can deteriorate or wear out from use. Additionally, as a changing climate leads to intensifying natural hazards, the loading conditions at the dam may increase beyond previously observed levels and reveal latent defects that were previously unknown. A number of recent dam incidents and failures have occurred at dams that had generally been performing satisfactorily over many decades, including at Oroville Dam in California (), Spencer Dam in Nebraska () and Edenville and Sanford Dams in Michigan (). In Maryland this list includes incidents at Cascade Lake (), Riawalkin Pond (), and Greenbrier Dam ().
It is our goal to work closely with dam owners to identify and correct potential problems before they become serious. If we find a deficiency during an inspection, we work with the dam owner to address and remedy the condition in a timely manner. If a dam owner is slow to remediate the problem, or is recalcitrant, a graduated enforcement protocol is in place that can eventually lead to an administrative court hearing and contempt of court charges. When necessary, we may direct the dam owner to implement their emergency action plan (EAP) and hire an engineer to prepare plans to remove or repair the dam. In cases of imminent failure and a failure of the dam owner to take necessary actions, Maryland law allows the Department to take charge of the dam and immediately employ any remedial means necessary to protect life and property. Costs incurred by the Department in such cases must be repaid by the owner in a timely manner. Failure to repay the Department can lead to a lien being placed on the property.
Yes. The Department recommends that a simple visual assessment of changes in downstream development occur at least annually – and if changes are observed, a new breach analysis may be required. Even where no changes are observed, the Department recommends that analyses and maps be updated a minimum of every 10 years for high hazard dams and 15 years for significant hazard dams. This ensures that the latest data, models and methodologies are used and can be relied on in an emergency.
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