A dam is defined by KRS 151.100 as any artificial barrier that compounds or diverts water and is either 25-feet in height from the downstream toe to the crest of the structure or has a maximum water storage elevation capacity of 50-acre feet or more. Dams serve a multitude of purposes, including human water supply, irrigation, energy generation, recreation, and flood control.
There are two primary types of dams: embankment and concrete. Embankment dams are the most common and are constructed using either natural soil or rock or waste material from a mining or milling operation. They are often referred to as “earth-fill” or “rock-fill” based upon which of those two types of materials is used to compact the dam. Concrete dams are generally categorized as either gravity or buttress dams. Gravity dams rely on the mass of the concrete and friction to resist the water pressure. A buttress dam is a type of gravity dam where the large mass of concrete is reduced and the force of water pressure is “diverted to the dam foundation through vertical or sloping buttresses.”
The Energy and Environment Cabinet, authorized by KRS 151.293 Section 6 to inspect existing structures that meet the above definition of a dam, further notes three classifications of dams:
Within the BRADD region, there is one High Hazard (C) Dam: Mill Creek MPS 4 in Monroe County.
There are two primary types of dams: embankment and concrete. Embankment dams are the most common and are constructed using either natural soil or rock or waste material from a mining or milling operation. They are often referred to as “earth-fill” or “rock-fill” based upon which of those two types of materials is used to compact the dam. Concrete dams are generally categorized as either gravity or buttress dams. Gravity dams rely on the mass of the concrete and friction to resist the water pressure. A buttress dam is a type of gravity dam where the large mass of concrete is reduced and the force of water pressure is “diverted to the dam foundation through vertical or sloping buttresses.”
The Energy and Environment Cabinet, authorized by KRS 151.293 Section 6 to inspect existing structures that meet the above definition of a dam, further notes three classifications of dams:
- High Hazard (C) – Structures located such that failure may cause loss of life or serious damage to houses, industrial or commercial buildings, important public utilities, main highways or major railroads.
- Moderate Hazard (B) – Structures located such that failure may cause significant damage to property and project operation, but loss of human life is not envisioned.
- Low Hazard (A) – Structures located such that failure would cause loss of the structure itself but little or no additional damage to other property.
Within the BRADD region, there is one High Hazard (C) Dam: Mill Creek MPS 4 in Monroe County.
The American Society of Civil Engineers gave Kentucky a D+ on dam infrastructure, which is only slightly better than the national average. The average US dam is 60 years old, and most dams in Kentucky are over 50. As of 2019, 80 dams in the state are classified as two-fold risks, meaning that they are both high hazards and in poor or unsatisfactory condition. 47% of these 80 dams received that rating partially because they cannot hold enough rain during catastrophic storms. 89% of high hazard dams in Kentucky do not have complete emergency action plans on file with the state. 74% have simplified draft plans, but these are not widely shared and have not been adopted by local officials.
There are three types of Dam Failure:
- Structural: This common cause is responsible for nearly 30% of all dam failure in the United States. Structural failure of a dam occurs when there is a rupture in the dam or its foundation.
- Mechanical: Refers to the failure or malfunctioning of gates, conduits, or valves.
- Hydraulic: Occurs when the uncontrolled flow of water over the top, around, and adjacent to the dam erodes its foundation. Hydraulic failure is the cause of approximately 34% of all dam failures.
Dam failures cause flooding much different from natural flooding. A flood from a dam failure may arrive before any warning or evacuation can take place and the resulting wall-of-water makes evacuation based on limited environmental cues very problematic. The failure of large dams results in flooding with enough energy to damage or destroy residences and other structures. Dam failure can occur at any time, but is often the result of other hazards, such as flooding or earthquake.
Potential Impacts: Dam failure can cause spectacular destruction, which can potentially lead to injuries or deaths.
People:
An individual’s vulnerability depends on:
Built Environment:
Actual dam failure not only results in the loss of life, but also results in considerable loss of capital investment and income, as well as property damage. In the event of a catastrophic dam failure, community systems will be severely strained. Debris carried downstream can block roads, disrupt traffic patterns, and delay the delivery of essential services along traffic corridors. The region will experience a disruption of lifeline facilities and emergency services. The loss of a reservoir (drinking water source) can also cause considerable hardship for the community that relies upon it for its water supply.
Natural Environment:
Dam failure can displace aquatic species, cause erosion, and disrupt habitats. Other environmental effects as the result of flooding from dam failure include the likely dispersal of debris and hazardous materials downstream that could damage local ecosystems.
Potential Impacts: Dam failure can cause spectacular destruction, which can potentially lead to injuries or deaths.
People:
An individual’s vulnerability depends on:
- Proximity downstream of the dam.
- Hazard class of the dam. For example, dams with the hazard class of C are expected to cause the loss of human life.
- Regulations/plans in place. The state of Kentucky does not require high hazard dam owners to complete an Emergency Action Plan. Emergency Action Plans detail evacuation procedures and can help mitigate the risk of injuries and deaths from dam failure.
Built Environment:
Actual dam failure not only results in the loss of life, but also results in considerable loss of capital investment and income, as well as property damage. In the event of a catastrophic dam failure, community systems will be severely strained. Debris carried downstream can block roads, disrupt traffic patterns, and delay the delivery of essential services along traffic corridors. The region will experience a disruption of lifeline facilities and emergency services. The loss of a reservoir (drinking water source) can also cause considerable hardship for the community that relies upon it for its water supply.
Natural Environment:
Dam failure can displace aquatic species, cause erosion, and disrupt habitats. Other environmental effects as the result of flooding from dam failure include the likely dispersal of debris and hazardous materials downstream that could damage local ecosystems.
The National Performance of Dams Program (NPDP), which maintains a database of failures for all dams listed in the National Inventory of Dams, lists ten dam failures in Kentucky since 1850, none of which occurred in the Barren River Region. The Barren River Region has been fortunate not to experience a dam failure; however, the potential is still there. The Corps of Engineers and Stantec (contractor) are conducting a study on the Rochester Dam’s potential failure. The final report with proposed alternatives and cost estimates were set to be released winter 2011.
Also of concern is Wolf Creek Dam. While it is not located within the BRADD region, failure of the dam would impact eastern Monroe County. In late 2007, the Army Corps of Engineers placed the dam under a 'high risk' for failure designation. A new long-term solution was proposed to solve, or control, the current seepage problem which began to be implemented in 2007 and is still underway.
Dam failure occurs as an indirect effect of climate change, driven by other hydrologic variables. Climate change leads to an increase in rainfall that contributes to a rise in water level. The water level can eventually rise above the dam, known as overtopping, and cause it to fail. Climate change is not often factored into the building of dams, which can cause damage in the future as storm severity and intensity increases, or from a change in rainfall patterns, which are predicted to occur in coming decades.
Potential impacts include:
Potential impacts include:
- Economic loss
- Infrastructure damage
- Flash flooding
- Disrupt ecosystems and biota
- Threats to life and property