Flooding

Table of Contents

As defined by USGS, flooding is a relatively high stream flow that overflows the natural or artificial banks of a stream or that submerges land not normally below water level, and, as a natural event, is caused in a variety of ways. Winter or spring rains, coupled with melting snows, can fill river basins too quickly. Torrential rains from decaying hurricanes or other tropical systems can also produce flooding. The excess water from snowmelt, rainfall, or storm surge accumulates and overflows onto lowlands, adjacent to rivers, lakes, and oceans which are subject to recurring floods; most commonly referred to as floodplains.

Currently, floodplains in the U.S. encompass over 16 million households. In the state of Kentucky, approximately 227,000 properties are within the 100-year floodplain and thus face a substantial risk of flooding. [1]

Description

Floodplains are defined as the low lands adjoining the channel of a river, stream or watercourse, or adjoining the shore of an ocean, lake or other body of standing water, which have been or may be inundated by flood water.

100-year floodplain is the area that is predicted to flood if a 100-year storm happens. 100 year storm events have a 1% chance of happening annually. Essentially,  floodplain has a 1 in 100 shot of flooding in any given year.

500-year floodplain follows the same concept. There is a .2% chance of a flood happening in a 500-year floodplain annually. The floodplain has a 1 in 500 shot of experiencing a flood in any given year. 

There are a multitude of reasons that floods may occur, with each type of flooding having a variety of environmental effects post-flood:

  • Regional Flooding can occur seasonally when winter or spring rains, coupled with melting snow, fill river basins with too much water too quickly.
  • River or Riverine Flooding is a high flow or overflow of water from a river or similar body of water, occurring over a period of time too long to be considered a flash flood. 
  • Flash Floods are quick-rising floods that usually occur as the result of heavy rains over a short period of time, often only several hours or even less.
  • Ice-Jam Flooding occurs on rivers that are totally or partially frozen.
  • Storm-surge flooding is water which is pushed up onto otherwise dry land by onshore winds.
  • Dam-and Levee-Failure Flooding are potentially the worst flood events. When a dam fails, an excess amount of water is suddenly released downstream, destroying anything in its path. 
  • Debris, Landslide, and Mudflow Flooding is created by the accumulation of debris, mud, rocks, and logs in a channel, forming a temporary dam.
  • Urban drainage (stormwater) flooding: occurs in areas that have been developed and thus rely on artificial drainage systems to eliminate excess water effectively. Because of the urbanized environment (i.e. paved streets, dense development, etc.), rainfall cannot easily be absorbed into the ground or find its way to a stream. This water can then flood streets and homes. 

Riverine, flash, and urban flooding are the most common types of flooding in Kentucky. 

Extent

For hazard mitigation planning purposes, the extent or the scale of flooding is measured in depth of flooding. To find records of past flood depth by jurisdiction, KIPDA used stream gage data, NCEI narratives, and local newspaper articles to identify extent. This information is displayed in the accordion below. 

Please note that because the cities in the KIPDA region have low populations and occupy small portions of each county’s overall acreage, the county is the predominant actor for mitigation efforts. Therefore, in cities where the depth data is not available, the depth data that correlates to the County, also applies to the city. 

  • Bullitt County
    • 3/29/2005: The Rolling Fork River at Boston crested at 36.07 feet around 445 PM EST on March 29. Flood stage at Boston is 35 feet. Minor flooding occurs at this level, with agricultural bottomland covered. [2]
    • 7/21/2006: Up to a foot and a half of water was flowing over Highway 44 near the Salt River bridge near Shepherdsville. In Hillview, flooding was reported near Summit Drive. [2]
  • Fox Chase
    • Depth data is not available.
  • Hebron Estates
    • Depth data is not available.
  • Hillview
    • 9/23/2006: Six inches of water covered Old Preston Highway at Zoneton Road. Water was over Kentucky Highway 480 between mile markers 9 and 10. [2]
    • 8/4/2009: Hillview Blvd was closed and barricaded as 16 to 18 inches of swiftly moving water raced over the roadway. [2]
  • Hunters Hollow
    • Depth data is not available.
  • Lebanon Junction
    • Depth data is not available.
  • Mount Washington
    • Depth data is not available.
  • Pioneer Village
    • Depth data is not available.
  • Shepherdsville
    • 4/25/2011: The Salt River at Shepherdsville crested around 33.1 feet at 10 AM EST on April 28. Flood stage at Shepherdsville is 32 feet. Minor flooding occurs at this level, with water covering Kentucky 61 at the north end of the bridge. [2]
    • 7/12/2011: Local Broadcast Media reported two to three feet of water on North Buckman Street between Walgreens and Big-0 Tire Company. [2]
    • 2/25/2018: The Salt River at Shepherdsville went into moderate flood stage. The river crested at 35.01 feet which is 3.01 feet above flood stage. Preston Highway closed in downtown due to high water from the Salt River overflowing the road. [2]
  • Henry County
    • 03/05/2015: Several inches of snow followed by 1 to 2 inches of rain resulted in the Kentucky River at Lockport to rise above flood stage. The river crested at 37.69 feet during the early morning hours of March 9th. The river remained above flood stage until the morning hours of March 12th.[2]
    • 3/14/2015: Heavy rainfall pushed the Kentucky River at Lockport into flood. The river crested at 34.74 feet on March 15th. [2]
    • 4/3/2015: Heavy rain brought the Kentucky River at Lockport into flood, cresting at 43.04 feet on the morning of April 5th. [2]
    • 4/15/2015: Heavy rain that fell on top of very saturated ground brought the Kentucky River at Lockport to flood. The river crested at 36.02 feet late on April 16th. [2]
  • Campbellsburg
    • Depth data is not available.
  • Eminence
    • Depth data is not available.
  • New Castle
    • 8/29/2003: A car was washed into a stream adjacent to Hillsboro Road two miles northwest of New Castle. Two to three feet of water covered the road. Other roads were flooded and impassable near Pendleton. [2]
  • Pleasureville
    • No depth data available.
  • Smithfield
    • No depth data available.
  • Oldham County
    • 1/7/2005: The Ohio River upper gage at Louisville crested at 28.34 feet around 1245 PM EST on January 12. Flood stage at the upper gage is 23 feet. Minor flooding occurs at this level. Some homes along River Road in Louisville are flooded. Large portions of River Road were closed from Louisville to Goshen. Most of Riverside Drive in Oldham County was flooded, limiting access to the Oldham Acres and Harmony Village areas. Some homes in Oldham Acres were flooded, but only minimal damage was reported. [2]
    • 7/14/2006: Three feet of water was reported over State Highway 146 near a gas station in Buckner. Ash Avenue in Peewee Valley was closed due to high water. Moody Lane south of Lagrange and Highway 22 near Crestwood had high water but were passable. Numerous accidents had occurred throughout the county due to hydroplaning. [2]
  • Crestwood
    • No depth data available.
  • Goshen
    • 7/14/2015: The Harrods Creek stream gage at Highway 329 near Goshen peaked at 16.77 ft and a peak flow of 16,000 cubic feet per second flow. This was the highest peak from the Harrods Creek stream gage from 2000 to 2020. [3]
  • La Grange
    • 5/19/2005: Four to five feet of water covered Moody Lane in La Grange. Numerous roads were closed in Pewee Valley and other locations around the county. [2]
  • Orchard Grass Hills
    • No depth data available.
  • Pewee Valley
    • 8/4/2009: Eight to ten inches of water was flowing over Highway 362. [2]
    • 8/10/2009: Eighteen inches of water was covering HWY 362 in Pewee Valley. [2]
    • 4/23/2011: Fast moving water up to 1.5 feet was reported over Hwy. 362, Ash Ave., in Pewee Valley near Hawley Gibson Rd. [2]
  • River Bluff
    • No depth data available

Shelby County & Shelbyville

  • 04/02/2015: The Shelby Sentinel reported on Tuesday April 7th, 2015:
    • “The first incident occurred Thursday [04/02/2015] afternoon, Shelbyville Fire Chief Kevin Baker said. “We had a young lady who on Washington Street at about 8th Street, failed to follow good reasoning and drove into the water,” he said, adding her car was trapped in about 14 inches of water. [4]
  • Simpsonville:
    • No depth data available at this time. 

Spencer County & Taylorsville:

  • 2/19/2000: The Brashears Creek stream gage in Taylorsville peaked at 28.17 ft and a peak flow of 29,200 cubic feet per second flow. This was the highest peak from the Brashears Creek stream gage from 2000 to 2020. [4]
  • Trimble County
    • 9/20/2009: Highway 625 at Mount Pleasant Road was closed, as was Highway 2871, which had two feet of water flowing over the roadway. [2]
    • 10/9/2009: Kentucky 625 at Mount Pleasant had four feet of water flowing over the bridge. Five feet of water flowed over the pavement at US 42 and Connector Road, making it impassable. [2]
  • Bedford
    • 3/11/2006: The Connector Road in Bedford was covered by four feet of water. It was closed and barricaded. Mount Pleasant Road was closed. The Highway 625 bridge was closed. Highway 316 was closed near Highway 421. [2]
  • Milton
    • 1/10/2005: The Ohio River at Clifty Creek, Indiana crested at 452.0 feet around 700 PM EST on January 11. Flood stage at Clifty Creek is 451 feet. Minor flooding occurs at this level. Lower parts of Milton, Kentucky flood. [2]

Location + Past Events

Historic Events

Two of the most damaging floods in the region are detailed below. 

  • The Ohio River Great Flood of January 1937 surpassed all prior floods during the previous 175 years of modern occupancy of the Ohio River Valley. The overall scope of the flood surpassed the major floods of 1773 and 1884, and geological evidence suggests the 1937 flood outdid any previous flood. Seventy percent of Louisville was submerged, forcing 175,000 residents to flee. A NOAA source estimated that damage was done to the tune of $250,000,000 in 1937 dollars, or over $3.3 billion in current dollars. Flood waters of the Salt and Rolling Fork Rivers covered much of Bullitt County including Shepherdsville, Lebanon Junction and Pitts Point. In Shepherdsville the flood waters “submerged every home, store, the bank, the Court House, jail and all other buildings.”
  • In March 1997, thunderstorms and large areas of heavy rain repeatedly moved over the same areas producing large amounts of rainfall. The deluge resulted in record flooding along smaller streams and some of the worst flooding along the Ohio River since 1964 and in some places, since the Great Flood of 1937. Barge traffic was halted on the Ohio River due to the locks flooding. In the Louisville metro area about $200,000,000 in damage was attributed to the flooding, with 50,000 dwellings affected. Interstates 64 and 65 were closed. A 13 year old boy was killed as he drowned while trying to clean out a culvert in Shelby County. The Salt River in Shepherdsville was above flood stage from March 2 – March 9 cresting on March 3 at 8.9 feet above flood stage.

FEMA Disaster Declarations

Since 2000, the KIPDA Region has experienced 17 FEMA disaster declarations related to flooding. Use the dashboard below to view details about these events and select by county. 

NOAA Flooding Events

To receive a FEMA declaration, the flooding event must be part of a major disaster; however, few flooding events meet this criteria. Therefore, it is important to obtain data from additional sources such as the National Weather Service (NWS) and the National Oceanic Atmospheric Administration (NOAA). The events shown on the map below include heavy rain, flash flooding, and riverine flooding, and these events were reported to NOAA’s National Center for Environmental Information (NCEI). Please note that many locations of flooding and heavy rain events were estimated based on event description, and several events impacted multiple locations. The number of events only shows distinct flooding or heavy rain events. 

View Data here

NFIP + Impact

NFIP Property Damage

Flooding is the most costly disaster not only in Kentucky but in the United States. Because of the financial risk of living in a floodplain, the U.S. government offers public flood insurance through the National Flood Insurance Program (NFIP) in order to reduce the socio-economic impact of floods. Most homeowner’s insurance policies do not cover floods, and therefore it is essential to have flood insurance if your home is at a high risk for flooding. Even one inch of water can cause up to $25,000 of damage. Communities, who chose to participate in the NFIP program, must conform to certain guidelines. Due to the structure of the NFIP program, most insurance policies are broken down by city and those properties outside of city limits are absorbed by the county. 

The following dashboard displays NFIP payments and losses in the KIPDA region between 1976 and 2020. Please note that the these are payments not claims, and therefore they do not encompass the full extent of property damage in the region. Moreover, these numbers are only for homes with flood insurance. Those without flood insurance are not included. Losses represent the number of claims that received payment.

The following cities do not participate in the NFIP because there are no special flood hazard areas identified: 

  • Mount Washington
  • La Grange
  • Pewee Valley
  • River Bluff
The following cities do not participate in the NFIP due to small population, limited staff, and/or lack of floodplain coordinator or floodplain ordinance: 

  • Fox Chase 
  • Hebron Estates
  • Campbellsburg
  • Eminence
  • Smithfield
  • Bedford

Finally, please note that some cities/communities like Louisville Metro fall in counties where they do not traditionally belong due to changes in annexation.

View data here

Repetitive Loss Properties

Properties in floodplains may experience several flooding events and file multiple NFIP claims. Properties that receive 2 or more claim payments of $1,000 or more from NFIP are considered repetitive loss. The following chart displays repetitive loss claims in the KIPDA Region between 2000 and 2020. 

View data here

Repetitive Loss Property Details

Using both the National Flood Insurance Program (NFIP) and the FEMA Flood Mitigation Assistance definitions for what constitutes “Repetitive-Loss” (RL) and “Severe Repetitive-Loss” (SRL) properties, Bullitt County counts sixteen (16) total properties that have experienced repetitive losses.

Bullitt County, unincorporated possesses four (4) of the sixteen (16) properties generally that have experienced repetitive losses.

Of these four (4) properties, all four (4) are single-family occupancy residential properties and all four (4) are considered RL according to the NFIP definition only. (There are no RL properties according to the FMA definition and there are no SRL properties using either the NFIP or FMA definitions.)

The City of Lebanon Junction possesses six (6) of the sixteen (16) properties generally that have experienced repetitive losses.

Of these six (6) properties, four (4) are single-family occupancy residential properties. Two (2) are labeled “Other-Non-Residential.” (FEMA requires insurers to categorize NFIP non-residential building policies either as “Business” policies or as “Other Non-Residential” policies.) All six (6) properties are considered RL according to the NFIP definition only. (There are no RL properties according to the FMA definition and there are no SRL properties using either the NFIP or FMA definitions.)

The City of Shepherdsville possesses six (6) of the sixteen (16) properties generally that have experienced repetitive losses.

Of these six (6) properties, five (5) are single-family occupancy residential properties. One (1) is a “Business (Non-Residential)” property. Two (2) of the six (6) properties are designated RL and SRL by both NFIP and FMA definitions. Both of these SRL properties are single-family occupancy residential properties. The remaining four (4) properties, including the one (1) “Business (Non-Residential)” property, are considered RL by the NFIP definition only.

Using both the National Flood Insurance Program (NFIP) and the FEMA Flood Mitigation Assistance definitions for what constitutes “Repetitive-Loss” (RL) and “Severe Repetitive-Loss” (SRL) properties, Henry County counts two (2) total properties that have experienced repetitive losses.

 

Henry County, unincorporated (that includes unincorporated area Lockport) possesses both properties generally that have experienced repetitive losses.

Of these two (2) properties, both are single-family occupancy residential properties and both are considered RL according to the NFIP definition only. (There are no RL properties according to the FMA definition and there are no SRL properties using either the NFIP or FMA definitions.)

 

Within the official Repetitive-Loss/Severe Repetitive-Loss list, there is one (1) additional property listed as being within Henry County, but that has as its community Louisville/Jefferson County Metropolitan Government. This third property is a single-family occupancy residential property and it is considered an RL and SRL according to the NFIP definition and is considered an SRL according to FEMA’s FMA program definition.

Using both the National Flood Insurance Program (NFIP) and the FEMA Flood Mitigation Assistance definitions for what constitutes “Repetitive-Loss” (RL) and “Severe Repetitive-Loss” (SRL) properties, Oldham County counts ninety-nine (99) total properties that have experienced repetitive losses.

 

Oldham County, unincorporated possesses all 99 properties generally that have experienced repetitive losses.

Of these 99 properties, ninety-six (96) are single-family occupancy residential properties, one (1) is a two- to four-family occupancy residential property, one (1) is a “Business (Non-Residential)” property, and one (1) is labeled as an “Other Non-Residential” property. (FEMA requires insurers to categorize NFIP non-residential building policies either as “Business” policies or as “Other Non-Residential” policies.)

Of the single-family occupancy residential properties, forty (40) are considered RL by the NFIP definition only; two (2) are considered RL by FEMA’s FMA program definition only; three (3) are considered RL by both the NFIP and FEMA’s FMA program definitions; three (3) are considered SRL by FEMA’s FMA program definition only; one (1) is considered RL by the NFIP definition and is considered SRL by FEMA’s FMA program definition; thirty-seven (37) are considered RL and SRL by the NFIP definition and are considered SRL by FEMA’s FMA program definition; and ten (10) are considered RL and SRL by both NFIP and FEMA’s FMA program definitions. 

The one (1) two- to four-family occupancy residential property meets the criteria for RL and SRL designations under the NFIP definition and meets the criteria for SRL designation under FEMA’s FMA program definition.

The one (1) “Business (Non-Residential)” property is considered RL according to the NFIP definition only.

The one (1) “Other Non-Residential” property is considered both RL and SRL by both NFIP and FEMA FMA program definitions.

 

Within the official Repetitive-Loss/Severe Repetitive-Loss list, there are seven (7) additional properties listed as being within Oldham County, but that have as their community Louisville/Jefferson County Metropolitan Government. All seven (7) additional properties are single-family occupancy residential properties. Five (5) of these seven (7) properties are considered RL by the NFIP definition only. The remaining two (2) of the seven (7) additional properties are considered RL and SRL according to the NFIP definition and are considered an SRL according to FEMA’s FMA program definition.

Using both the National Flood Insurance Program (NFIP) and the FEMA Flood Mitigation Assistance definitions for what constitutes “Repetitive-Loss” (RL) and “Severe Repetitive-Loss” (SRL) properties, Shelby County counts one (1) total property that has experienced repetitive losses.

 

The City of Shelbyville houses the one (1) property that has experienced repetitive losses. This one (1) property is a single-family occupancy residential property and is considered RL by the NFIP definition only.

Using both the National Flood Insurance Program (NFIP) and the FEMA Flood Mitigation Assistance definitions for what constitutes “Repetitive-Loss” (RL) and “Severe Repetitive-Loss” (SRL) properties, Spencer County counts four (4) total properties that have experienced repetitive losses.

 

Spencer County, unincorporated possesses two (2) of the four (4) properties generally that have experienced repetitive losses.

Of these two (2) properties, one (1) is a single-family occupancy residential property and one (1) is a two- to four-family occupancy residential property. Both the single-family and two- to four-family occupancy residential properties are considered RL and SRL according to the NFIP definition and are considered SRL by FEMA’s FMA program definition.

 

The City of Taylorsville possesses two (2) of the four (4) properties generally that have experienced repetitive losses.

Of these two (2) properties, both are single-family occupancy residential properties. Both properties are considered RL according to the NFIP definition only. (There are no RL properties according to the FMA definition and there are no SRL properties using either the NFIP or FMA definitions.)

Using both the National Flood Insurance Program (NFIP) and the FEMA Flood Mitigation Assistance definitions for what constitutes “Repetitive-Loss” (RL) and “Severe Repetitive-Loss” (SRL) properties, Trimble County counts zero (0) total properties that have experienced repetitive losses.

NFIP Policies in 100-Year Floodplain

The following dashboard displays NFIP information about the number of policies, cost of coverage, and total coverage insured for homes in the KIPDA region. 

View Data here

Probability

Occurrence

Between 2000 and 2020 (21 years), the KIPDA region experienced 65 distinct flooding and heavy rain events. Please note that flooding and heavy rain events, which share the same episode number from NCEI, are classified as the same event.

Data clarification: Each county’s section includes its respective cities as well. Events that are listed under a city exclusively happened in the city and not countywide. Events counting towards the county’s total happened countywide. Not every city experienced a strictly city wide event, and county counts would likely include most if not all cities. 

  • Bullitt County: 17 county-wide flooding and heavy rain events/21 years = 80% chance of flooding/heavy rain event happening annually.
    • Hillview: 1 city-wide event/21 years=5% chance of city-wide flooding/heavy rain event happening annually.
    • Lebanon Junction: 1 city-wide event/21 years=5% chance of city-wide flooding/heavy rain event happening annually.
    • Mount Washington: 1 city-wide event/21 years=5% chance of a city-wide flooding/heavy rain event happening annually.
    • Shepherdsville: 5 city-wide events/21 years=24% chance of a city-wide flooding/heavy rain event happening annually.
    • No specific, city-wide events were recorded for Hebron Estates, Fox Chase, and Pioneer Village.
  • Henry County: 17 county-wide flooding and heavy rain events/21 years= 80% chance of flooding/heavy rain events happening annually.
    • New Castle: 2 city-wide events/21 years= 10% chance of city-wide flooding/heavy rain event happening annually.
    • No specific, city-wide events were recorded for Campbellsburg, Eminence, Pleasureville, and Smithfield.
  • Oldham County: 20 county-wide flooding and heavy rain events/21 years=95% chance of flooding/heavy rain event happening annually.
    • Crestwood: 1 city-wide event/21 years=5% chance of city-wide flooding/heavy rain event happening annually.
    • Goshen: 1 city-wide event/21 years=5% chance of city-wide flooding/heavy rain event happening annually.
    • La Grange: 2 city-wide events/21 years=10% chance of city-wide flooding/heavy rain event happening annually.
    • Pewee Valley: 4 city-wide events/21 years=19% chance of city-wide flooding/heavy rain event happening annually.
    • No specific city-wide events were recorded for Orchard Grass Hills or River Bluff.
  • Shelby County: 16 county-wide flooding and heavy rain events/21 years=.76% chance of flooding/heavy rain event happening annually.
    • Shelbyville: 2 city-wide events/21 years=10% chance of flooding/heavy rain event happening annually.
    • No specific city-wide events were recorded for Simpsonville.
  • Spencer County: 15 county-wide flooding and heavy rain events/21 years= 71% chance of a flooding and heavy rain events annually.
    • Taylorsville: 3 city-wide events/21 years=15% chance of a flooding and heavy rain events annually.
  • Trimble County: 17 county-wide flooding and heavy rain events/21 years=81% chance of flooding/heavy rain event happening annually.
    • Bedford: 1 city-wide event/21 years=5% chance of flooding/heavy rain event happening annually.
    • Milton: 2 city-wide events/21 years=10% chance of flooding/heavy rain event happening annually/

Climate Change

The National Climate Assessment reported that the Kentuckiana area had experienced a 10-15% increase in precipitation when comparing the 1991-2012 average to the 1901-1960 average and reported an expected increase of heavy precipitation of over 40% by 2100.

These predictions are further supported by the US Army Corp’s 2017 report where they said that flooding, drought and power failures are likely to become more common in both Indiana and Kentucky, along with the entire Ohio River Basin. [4] The Courier Journal spoke on the Army Corp’s report, saying that “…areas northeast, east and south of the Ohio River are expected to see as much as 50 percent more precipitation, with resulting higher tributary stream flows. [5]” This increased precipitation is expected to occur in the spring. In the fall, drought is expected to cause a lowering of the water level by as much as 35%.

Studies show that the occurrence of heavy precipitation is moving more towards the spring, including snowmelt. [6] [7] This will put a strain on agricultural drainage as well as increase the chance of flooding. Some simulations predict that streamflow will increase significantly in most Midwestern rivers by the 2080s, all but guaranteeing a flood. [8] The area has already been experiencing floods most likely caused by climate change. This increase in precipitation, coupled with the D+ rating on dam infrastructure that Kentucky received from the American Society of Civil Engineers, also increases the risk of dam failure. [9] The chance of floods occurring in the region are only increased by climate change, both floods caused by dam failure, and floods from undammed bodies of water.

Overall Probability

Overall, the KIPDA HMP ranks the probability of an event for the region as extremely high. 

Vulnerability

KIPDA Region Floodplains

Please use the button below to view the floodplain map for the KIPDA Region. 

Online Floodplain map

Floodplain Acreage

The dashboard below shows the number of acres in the floodplain by county and community. It also shows the percentage of the city/county’s land in the floodplain. For example, 37.6% of the city of Shepherdsville is in the floodplain. Finally, it includes the latest FEMA Insurance Rate Map (FIRM) effective date. This is the day when the National Flood Insurance Program (NFIP) map for a community became effective and all sanctions of the NFIP apply.

Please note that the county numbers include cities and non-annexed areas. To change counties click the drop down, and to download data as a PDF click the download data button. 

View data here

Floodplain Vulnerability

In order to generate approximate estimates of property value located within KIPDA HMP Floodplains, 2018 Microsoft Bing Building Footprints were compared with KIPDA HMP Floodplain boundaries. The building footprints which intersected the Floodplain polygons were selected and identified as being potentially impacted during an event. The impacted building footprints were then joined with PVA parcel data to assign a value of potential losses during a catastrophic/total loss scenario. 

As some are buildings are built very close to the parcel boundaries, the process created a handful of duplicate entries, where parcel boundaries crossed over buildings. Both the buildings and parcel data sets are imperfect, but the best available information at the time of plan creation. Duplicates were evaluated visually, and the most correct parcels based on available information were kept, and the most incorrect were deleted. Summary statistics were used to generate counts of the number of buildings impacted as well as the total parcel value for each building. 

These values assume that the entire parcel is a total loss.  It is understood that this is incredibly likely to be an over-estimate as the land would remain after an event and most scenarios will not result in a total loss of the building(s). Parcels do not always exactly fit into this model because there can be multiple buildings on the parcel. Other parcels do not fit the criteria because they have no real-estate or improvement value associated with them. Some counties had different attributes assigned to their parcel data such as Real-Estate value versus Improvement value.  Employee discretion was used to determine the most appropriate values to use given the available information per county. 

Salt River Watershed

The Salt River Basin (Salt River Watershed) is one of the twelve major river basins in the state. River basins are the portion of land that is drained by a river and its tributaries. Bullitt, Henry, Jefferson, Oldham, Spencer, and Shelby counties are all part of the Salt River Watershed. The primary flooding source in the watershed is the Salt River. It flows through Mercer, Anderson, Spencer, and Bullitt counties before its confluence with the Ohio River. The Salt River flows through the middle of Shepherdsville. Other flooding sources within the Salt River Watershed that impact KIPDA’s HMP counties include Pond Creek in southern Jefferson County, Taylorsville Lake and dam in Spencer County, McNeely Lake and dam in southern Jefferson County. [10]

Flooding Environment

The accordion below describes the flooding environment in each county. Information from FEMA’s Flood Insurance Study (FIS) reports for each county informed these descriptions. 

Bullitt County is within the Salt River Watershed. There are multiple flooding sources within Bullitt County including Brooks Run, Knob Creek Tributary (Curry Branch), Bullitt Lick Creek, Long Lick Creek, Crooked Creek, Mud Run, Floyds Fork, Ohio River, Gravel Creek, Salt River, Knob Creek, and Whittaker Run. 

Shepherdsville, the county seat, is particularly vulnerable to flooding because the Salt River flows through it. The Rolling Fork River, a tributary of the Salt River, threatens the City of Lebanon Junction. [11]

Henry County falls within 3 watersheds/basins: Lower Kentucky, Salt River, and Silver-Little Kentucky. 

  • Lower Kentucky: its primary flooding source is the Kentucky River, and it contains the eastern half of Henry County.
  • Salt River: its primary flooding source is the Salt River, and it contains the southwestern part of Henry County.
  • Silver-Little Kentucky: its primary flooding source is the Little Kentucky River, and it contains most of the western half of Henry County.

The primary source of flooding within Henry County is the Kentucky River, and it primarily impacts low-lying areas around the river. [12]

Oldham County falls within 2 main watersheds/basins: Salt River and Silver-Little Kentucky.

  • Salt River: its primary flooding source is the Salt River, and it contains the southeastern half of the county.
  • Silver-Little Kentucky: its primary flooding source is the Salt River, and it contains the northwestern half of the county.

The principal source of flooding in Oldham County is the Ohio River. Flooding primarily occurs in the Westport area and the downstream edge of the county.[13]

Shelby County falls within the Lower Kentucky Watershed and the Salt River Watershed. It has minimal flooding issues. 

Spencer County is entirely contained by the Salt River Watershed. The primary sources of flooding within Spencer County are the Salt River and Brashears Creek. Flooding also happens along Taylorsville Lake and Dam, which is connected to the Salt River. Flooding primarily occurs in low-lying areas around these waterways. [14]

Oldham County falls within 2 main watersheds/basins: Lower Kentucky and Silver-Little Kentucky.

  • Lower Kentucky: its primary flooding source is the Kentucky River, and it contains the far east corner of Trimble County.
  • Silver-Little Kentucky: its primary flooding source is the Little Kentucky River, and it contains nearly the entirety of Trimble County.

The primary source of flooding in Trimble County is the Ohio River. [15]

Critical Facilities in the Floodplain

Critical infrastructure describes assets that are essential to a community’s functioning. KIDPA’s critical facilities include water and wastewater infrastructure, pipelines, schools, libraries, courthouses, police stations, fire departments, emergency operations centers, health departments, public housing, prisons, and hospitals. KIPDA staff used geospatial analysis to intersect critical facilities and the the Zone A floodplain (100-year floodplain). The map below displays critical infrastructure within the floodplain. 

Problem Statements

Through interviews, meetings, RiskMap participation, and its online map, KIPDA identified several problem areas for flooding in the region. Often, flood-related issues impacted critical infrastructure. 

  • Bullitt County: Stream erosion along Weavers Run Road
  • Lebanon Junction: Lebanon Junction has a levee that protects the city against flooding caused by Rolling Fork River; however, this levee also prevents water from exiting the city. During periods of heavy rain, the water has no where to go and can easily flood properties in the city.  A pump station is needed to allow for the discharge of floodwaters.
  • Lebanon Junction: Derby Street Bridge has flooded repeatedly, which has caused substantial erosion.
  • Louisville Municipal Sewer District’s (formerly owned by Bullitt County Sanitation District) Willabrook Sanitation Plant and its pump station are located in the floodplain. 
  • Shepherdsville: many of Shepherdsville Sewer’s wastewater facilities are located in the floodplain. The City of Shepherdsville runs Shepherdsville Sewer.  
  • New Castle: sewer line runs next to creek, and during heavy precipitation events, the line experiences issues.
  • Risk Map planning efforts for the Silver Little Watershed identified that the Interstate 71 bridge at fallen Timber Creek experiences frequent flooding. Evaluate possible solutions to control flooding at bridge.
  • Risk Map planning efforts  for the Silver Little Watershed identified houses located in floodplain along Sulphur Fork. Possible home buyout locations.
  • Stream bank erosion along sanitary treatment plant lagoon berm on West Moody Lane.
  • Risk Map planning efforts  for the Silver Little Watershed identified continuous flooding from Little Huckleberry Creek due to a possible undersized culvert. Problems also stem from the geometry of the stream. Evaluate the culvert. Replace/update with properly sized culvert.
  • Risk Map planning efforts for the Silver Little Watershed also identified a need for an updated, detailed study on Harrods Creeks in order to update the storm water management plan, identify regional basin locations, and improve hazard abatement.
  • Risk Map planning efforts for the Silver Little Watershed also identified that industrial expansion is occurring north of Darby Fork. Review current plans and FEMA studies to ensure that flood risk does not increase.

  • La Grange: several of La Grange Utilities’ lift stations do not have a backup generator to guarantee service during a hazard event like flooding.

  • Eighteen Mile Creek eroding bank along Eighteen Mile Creek Road

  • Floodwaters deposit mud and debris on Hidden Valley Road along Ohio River as floodwaters recede
  • Harmony Village and Oldham Acres culverts improvements. Require design for culvert sizing and potential elevation of road profile to reduce occurrence of flooding of road.
  • System capacity issues for stormwater along Ash Avenue.
  • Oldham County Water purchased property near floodplain to protect well field from contamination. Oldham County Water would like to remove the home that is currently located on the property and create an open-space area for flood protection.
  • Louisville Municipal Sewer District (MSD) has recently acquired assets from Oldham County Environmental Authority that are within the 100-year floodplain. Of the recently acquired assets two treatment facilities are within the 100-year floodplain of Floyd’s Fork, 2 pump stations are within the 100-year flood plain of the Ohio River, and 33 manholes are within the 100-year floodplain. This is concerning because treatment facilities within the flood plain are at risk of failing during flood events, resulting in discharge of untreated wastewater. Sanitary sewer overflows are possible when flood water infiltrates pump stations and manholes during flood events. Assets at risk of flooding may require relocation, upgrades, and or/ protections to improve resiliency during flood events, especially as frequency of extreme storms increases with climate change.

  • Most of the pumping stations within MSD’s recently acquired assets from the Oldham County Environmental Authority do not currently have permanent backup generators installed. Kentucky Division of Water requires backup powering of pumping stations to be provided if the station has under 24 hours of holding capacity. Backup power can be provided by an on-site generator or portable generator, as long as holding time is sufficient for maintenance teams to respond to the alarm and install the generator on site. Increased frequency and intensity of storm events presents additional risk to maintaining power at these facilities. Maintaining backup power generators and the connections at facilities is vital for preventing sanitary sewer overflows during flooding and storm events or other power outages.

  • Shelbyville Water has a pump station within a floodplain along Highway 55. Following heavy precipitation, the pump station becomes flooded, and past flood waters has almost reached the electrical components of the station in the past.
  • Shelby County Emergency Management reported that several roads have required water rescues in recent years due to flash flooding. These roads include:
    • Croppers Road
    • Brunerstown Road
    • Scotts Station Road
    • Fox Run Road
    • Picketts Dam area
    • Burch Branch Road
  • Plum Creek floods Old Heady Road, which makes it impossible to cross the bridge. In 2019, a car ignored signage and attempted to cross bridge during a flood event. One person drowned.
  • The Taylorsville Road crossing at Beshears Creek floods during heavy rain events.
  • June 18-19, 2021: torrential rain that flooded Hardy Creek Road, Richmond Hill Road, and Jones Lane.
  • Millers Branch Creek floods Miller Branch Road during periods of heavy rain. In the past, the county has needed to shut down the private section of the road due to flooding. 
  • Corn Creek regularly floods Joyce’s Mill Road. In 2015, Corn Creek washed out several mobile homes near Joyce’s Mill Road.
  • Every spring and fall water from a nearby creek washes over the bridge on Wise’s Landing Road, and the county has to close the bridge off for several days. A few homes and one business have to take a significant detour because of the bridge shut down. Therefore, the bridge needs to be elevated in order to deal with repetitive flooding issues. 

  • Bedford Wastewater Treatment Plant Access Road: the plant provides a critical service to the residents of Bedford; however, storm events, specifically flash flooding, threaten the city’s ability to provide this service. Several times a year, significant rainfall and subsequent flooding exceed the capacity of the culvert pipes, which lie underneath the sole WWTP access road. This can render the road to this vital service impassible. For example, during DR-4239-KY from July 11th to 20th of 2015, the roadway remained impassible for several days until heavy equipment could be secured to remove the damaged roadway surface. The roadway has been undermined many times since and repaired, and this process and expense will continue unless the road is raised and a properly sized culvert installed.

Planning & Zoning

KIPDA’s hazard mitigation graduate fellow, Anagha Gore, spent ten weeks and 400 hours analyzing flood policy in the KIPDA region. Her work yielded two primary results – a flood policy inventory and flooding report. The flood policy inventory includes flooding-related language from comprehensive plans and zoning codes. Her flooding report contains an analysis of flood policy and projects in the region as well as possible mitigation actions. 

Flooding in the KIPDA Region: an Analysis

Hazard Vulnerability Summary Analysis

The following accordion breaks down flood risk by community. The KIPDA region’s overall vulnerability to flooding is high.

  • Bullitt County
    • 17.4% of Bullitt County is within a floodplain, which is the highest percentage of any KIPDA county.
    • It is also one of the fastest growing counties in the state and has the largest population within the KIPDA Hazard Mitigation Region.
    • It has substantially more NFIP policies than any other county in the region at 500 with a value of over $82 million.
    • It has several critical facilities within the floodplain including its EMS facility, a library, Bullitt County Sheriff, Bullitt County Courthouse, Bullitt County Fiscal Court, several wastewater lift stations, and more. 
    • Its floodplain and storm water codes are limited. Moreover, its planning and zoning department needs additional staff in order to regulate growth in this flood-prone county. 
  • Overall, Bullitt County experiences high vulnerability to flood events. 
  • Lebanon Junction
    • 36.1% of Lebanon Junction is located within a floodplain, which is significantly high.
    • Lebanon Junction has a levee that protects the city against flooding caused by Rolling Fork River; however, this levee also prevents water from exiting the city. During periods of heavy rain, the water has no where to go and can easily flood properties in the city. 
    • Lebanon Junction also has a bridge that repetitively floods.
    • Lebanon Junction’s wastewater lift stations are within the floodplain.
  • Overall, Lebanon Junction experiences high vulnerability to flooding. 
  • Shepherdsville
    • 37.6% of Shepherdsville is located within a floodplain, which is the highest percentage of any city within the KIPDA region.
    • Shepherdsville is the county seat and has the largest population of any city in Bullitt County.
    • It has several critical facilities within the floodplain including its EMS facility, a library, Bullitt County Sheriff, Bullitt County Courthouse, Bullitt County Fiscal Court, several wastewater lift stations, and more. 
    • The Salt River flows through the city. 
  • Overall, Shepherdsville experiences high vulnerability to flooding.
  • Fox Chase
    • 8.4% of Fox Chase is within the floodplain.
  • Overall, Fox Chase experiences moderate vulnerability to flooding.
  • Hillview, Hebron Estates, Mount Washington, and Pioneer Village have less than 5% of land in the floodplain and do not contain critical infrastructure within the floodplain. Therefore, these communities experience moderate vulnerability to flooding.
  • Henry County
    • 6.2% of Henry County is within the floodplain, which is the second lowest percentage of KIPDA’s HMP counties.
    • It is a highly rural, and the second least populated county.
    • It has a HUD insured multifamily home within the floodplain.
    • It has very low density and is highly agricultural.
    • Henry County has received 6 FEMA declarations related to flooding since 2000. A declaration means that the  situation is beyond the capability of the State and affected local governments and supplemental federal assistance is necessary.
  • While Henry County may not be as acutely vulnerable as other counties, it experiences high vulnerability to flooding largely because of past disaster declarations.
  • New Castle
    • 6.7% of New Castle is within a floodplain.
    • It has a HUD insured multifamily home within the floodplain.
    • Since 2000, Highway 421 and other roadways near New Castle have experienced flash flooding.
  • New Castle experiences a moderate vulnerability to flooding.
  • Henry County’s other cities, Campbellsburg, Eminence, Pleasureville, and Smithfield are not within the floodplain; however, they can certainly still experience flooding. Overall, these cities exhibit moderate vulnerability to flooding.
  • Oldham County
    • 8.5% of Oldham County is within a floodplain.
    • Between 2000 and 2020, Oldham County has over $13 million in NFIP payments, which is substantially higher than any other county or community.
    • It also exhibits the highest number of repetitive loss properties -99.
    • Since 2014, the Oldham County Fiscal court has conducted millions of dollars of buyouts and elevations in flood prone neighborhoods near the Ohio River. It should be noted that these neighborhoods contain more expensive homes, and therefore are less likely to house vulnerable communities. Oldham County has the highest average home value in the region.
    • The county has a few wastewater lift stations located within the floodplain. 
  • Overall, Oldham County experiences high vulnerability to flooding.
  • Oldham County’s cities, Crestwood, Goshen, La Grange, Pewee Valley, Orchard Grass Hills, and River Bluff have less than 3% of land in the floodplain and do not contain critical infrastructure within the floodplain. Therefore, these communities exhibit moderate vulnerability to flooding. 
  • Shelby County
    • 3.2% of Shelby County is within a floodplain, which is the lowest percentage of any county. 
    • The county has four wastewater lift stations and one water treatment plant within the floodplain.
    • Shelby County has received 5 FEMA declarations related to flooding since 2000. A declaration means that the situation is beyond the capability of the state and affected local governments and supplemental federal assistance is necessary.
    • Since 1976, only 16 NFIP payments to homeowners have been made. This is the lowest of any county in the region.
  • While Shelby County may not be as acutely vulnerable as other counties, it experiences high vulnerability to flooding largely because of past disaster declarations. 
  • Spencer County
    • 10.9% of Spencer County is within the floodplain.
    • In 2019, a car ignored signage and attempted to cross a low water crossing on Old Heady Road. One person drowned. This is only death attributed to flooding in the KIPDA region since 2000.
    • Spencer County has two wastewater lift stations located in the floodplain.
    • While Spencer County is largely undeveloped and rural, it is one of the fastest growing counties in Kentucky according to the 2020 Census.
  • Overall, Spencer County experiences high vulnerability to flooding.
  • Taylorsville
    • 6.4% of Taylorsville is within a floodplain.
    • Taylorsville contains the Taylorsville Levee, which separates Taylorsville from the Salt River. The Taylorsville Levee is over 70 years old, and if it were to fail, catastrophic flooding could occur.
  • Overall, Taylorsville experiences high vulnerability to flooding.
  • Trimble County
    • 10.6% of Trimble County is within a floodplain.
    • Trimble County has five wastewater lift stations located in the floodplain – all in Milton.
    • Trimble County has received 7 FEMA declarations related to flooding since 2000. A declaration means that the situation is beyond the capability of the state and affected local governments and supplemental federal  assistance is necessary.
  • Overall, Trimble County experiences high vulnerability to flooding.
  • Bedford
    • Bedford is not located within a floodplain.
    • The Bedford Wastewater Treatment Plant has experienced issues with flooding because its only access road has been washed out during past heavy precipitation events.
  • Overall, Bedford experiences moderate vulnerability to flooding. 
  • Milton
    • 12.4% of Milton is within a floodplain.
    • Milton has five wastewater lift stations located in the floodplain.
    • Milton has a population less than 700, but it has 25 past NFIP payments to homeowners (1976-2020).
  • Overall, Milton experiences high vulnerability to flooding.

References

[1] First Street Foundation National Flood Assessment. Retrieved from https://assets.firststreet.org/uploads/2020/06/first_street_foundation__first_national_flood_risk_assessment.pdf

[2] National Oceanic and Atmospheric Administration (2021). Storm Events Database. [Data set]. National Centers for Environmental Information. Retrieved from https://www.ncdc.noaa.gov/stormevents/

[3] United States Geological Survey. (2021). National Water Information System: Mapper. [Data set]. Retrieved from https://maps.waterdata.usgs.gov/mapper/index.html

[4] United States, US Army Corps of Engineers, Institute for Water Resources. (2017). Ohio River Basin: Formulating climate change mitigation/adaptation strategies through regional collaboration with the ORB Alliance. US Army Corps of Engineers. Retrieved from https://usace.contentdm.oclc.org/digital/collection/p266001coll1/id/5108/. 

[5] Bruggers, J. (2017, December 01). Army engineers warn of brutal future for Ohio River region from climate change. Retrieved  from https://www.courier-journal.com/story/tech/science/environment/2017/11/30/ohio-river-valley-climate-change-report/831135001/

[6] Edwards, B. (2019, November 11). Galvanized by disaster. Retrieved from https://www.indianaenvironmentalreporter.org/posts/galvanized-by-disaster

[7] Did climate change cause the flooding in the Midwest and Plains? (2019, April 02). Retrieved from https:// www.yaleclimateconnections.org/2019/04/did-climate-change-cause- midwest-\flooding/

[8] Bruggers, J. (2019, November 27). Climate Change In Kentucky: ‘One Home Came Floating Down The River’. Retrieved  from https:// www.leoweekly.com/2019/11/climate-change-kentucky-one-home-came- \floating-river/

[9] Ironcore. (2020, July 16). Kentucky. Retrieved from https:// www.infrastructurereportcard.org/state-item/kentucky/

[10] Federal Emergency Management Agency (2016, December 16). Flood Risk Report: Salt River Watershed, KY. Retrieved from https://msc.fema.gov/portal/advanceSearch

[11] Federal Emergency Management Agency (2016, April 5). Flood Insurance Study: Bullitt County, KY and Incorporated Areas. Retrieved from https://msc.fema.gov/portal/advanceSearch

[12] Federal Emergency Management Agency (2021, March 23). Flood Insurance Study: Henry County, KY and Incorporated Areas. Retrieved from https://msc.fema.gov/portal/advanceSearch

[13] Federal Emergency Management Agency (2021, March 23). Flood Insurance Study: Oldham County, KY and Incorporated Areas. Retrieved from https://msc.fema.gov/portal/advanceSearch

[14]  Federal Emergency Management Agency (2020, September 18). Flood Insurance Study: Spencer County, KY and Incorporated Areas. Retrieved from https://msc.fema.gov/portal/advanceSearch

[15] Federal Emergency Management Agency (2021, March 23). Flood Insurance Study: Trimble County, KY and Incorporated Areas. Retrieved from https://msc.fema.gov/portal/advanceSearch