SECTION 4: RISK ASSESSMENT
Year of Failure
Dam Name
Location
Class at Time of Failure
Cause of Failure Hurricane Fran Hurricane Fran Hurricane Fran
Raleigh Zebulon Raleigh
1996 1996 1996 1996
Lake Raleigh Penny Hill Lake
High Low
Silver Lake*
Intermediate* Intermediate
Yates Mill Pond Hurricane Fran *These dams are now classified as high hazard due to downstream development and/or increased downstream traffic. Source: 2019 Wake County Multi-Jurisdictional Hazard Mitigation Plan Wake County PROBABILITY OF FUTURE OCCURRENCE Given the significant presence of high hazard dams in Wake County, failure of a dam is possible. Dam failure has not occurred in the county since 1996, however historical events alone do not provide an adequate estimate of potential future occurrence. With heavy rain events becoming more frequent and intense, conditions conducive to dam failure may occur more frequently as well.
Probability: 2 – Possible
Table 4.18 lists dams throughout Wake County that have a condition assessment of “poor” as of the date of their last inspection. A condition assessment of poor indicates the need for maintenance, monitoring, and/or repairs to mitigate risk of failure. Only three of these dams have an emergency action plan in place. Table 4.18 - High Hazard Dams in Wake County with Condition Assessment of “Poor”
Inspection Date
Nearest Downstream City & Distance (mi.) Smithfield (35 mi) Wake Forest (3 mi.)
EAP in Place
Dam Name
NID ID
Panther Lake Dam
NC00876 01/08/2026 NC04439 07/12/2022
No Yes No No No No No No No No No No No Yes No Yes
Lewis Dam
Ballentine Farms Pond Dam Ransdell-Wake Chapel Dam Charleston Village Pond Dam
NC04441
12/01/2022
NC06435 01/01/2025 NC07086 05/01/2035 NC04576 02/02/2024 NC06093 03/07/2025
Marshall Pond #2 Dam
Forestville (0 mi.) Raleigh (0 mi.) Garner (0 mi.) Garner (0 mi.) Garner (0 mi.) Raleigh (0 mi.) Garner (4 mi.) Raleigh (0 mi.)
Pine Knoll Dam Peacock Dam Weston #1 Dam Weston #2 Dam
NC04614
01/01/2025
NC05235 07/06/2023 NC05236 07/06/2023
North Ridge Country Club Hole #13 Dam NC06197 02/01/2024
Bullard and Patterson Dam
NC04504 03/01/2025 NC04626 02/01/2023 NC04519 11/24/2022 NC01706 03/01/2025 NC04949 03/22/2025
Massengill Dam Camp Pond Dam Grey Lake Dam Kildaire Farms Dam
Apex (0 mi.)
Source: North Carolina Dam Inventory, February 2024
CLIMATE CHANGE Studies have been conducted to investigate the impact of climate change scenarios on dam safety. The safety of dams for the future climate can be based on an evaluation of changes in design floods and the freeboard available to accommodate an increase in flood levels. The results from the studies indicate that the design floods with the corresponding outflow floods and flood water levels will increase in the future, and this increase will affect the safety of the dams in the future. Studies concluded that the total hydrological failure probability of a dam will increase in the future climate and that the extent and depth of flood waters will increase by the future dam break scenario.
Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan
WSP June 2024 Page 95
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