WICOMICO COUNTY, MARYLAND
Nuisance Flood Plan
2020
Revised September 30, 2020 Wicomico County Nuisance Flood Plan – 2020 Page 2
I. INTRODUCTION
This Nuisance Flood Plan has been created in accordance with Maryland House Bill 1427 (2019), §3-1018(b) and (c) which requires municipalities within the State of Maryland who experience nuisance tidal flooding to develop a plan to address this issue. The definition of nuisance flooding found in the Natural Resource Article of the Maryland Annotated Code (§3- 1001) is “high tide flooding that causes a public inconvenience”. In Wicomico County, this public inconvenience occurs when roadways become inundated by flood waters creating difficult driving when minor flooding occurs, or, in the case of moderate to major flooding, roads can become impassable. As noted in the Wicomico County 2016 Hazard Mitigation Plan, the western and southern parts of the County are most vulnerable to tidal flooding occurrences.
Wicomico County, Maryland is located in southeastern Maryland on the Delmarva Peninsula. This coastal community is primarily rural with a heavy agricultural influence. The City of Salisbury is at the core of the County’s business and manufacturing market. In addition to the City of Salisbury, there are six other incorporated towns within the County. They are: Delmar, Fruitland, Hebron, Mardela Springs, Pittsville, Sharptown and Willards. Only the City of Salisbury experiences tidal nuisance flooding and that municipality has submitted a separate Nuisance Flood Plan. For that reason, this plan only addresses nuisance tidal flooding within Wicomico County that lies outside of the City of Salisbury and the other incorporated townships.
MAP OF WICOMICO COUNTY
Wicomico County Nuisance Flood Plan – 2020 Page 3
II. SOURCES OF NUISANCE TIDAL FLOODING
Wicomico County is bordered on three sides by waterways – to the west by the Nanticoke River, to the south by the Wicomico River and Wicomico Creek, and to the east by the Pocomoke River. The latter water source is so close to its headwaters that it does not pose any tidal influences.
However, the Nanticoke and Wicomico Rivers are occasional sources of nuisance tidal flooding. There is a vast network of State, County and local roads providing transportation for those living and working within Wicomico County. These roads are also used as a link to final destinations by visitors passing through the County.
Roads within the County are classified as Major or Minor Collectors, or Local Roads. Major collector roads carry relatively large volumes of primarily local traffic from major development centers in the County to the closest arterial street or a local traffic destination. The basic purpose of a minor collector street is to collect traffic from primarily local activity centers in order to provide access to major collector streets. A minor collector also provides direct access to adjoining land uses. The most extensive part of the County’s highway network consists of its local streets which have the primary purpose of providing direct access to adjoining properties. A secondary purpose of local streets is to provide linkages with minor collector streets. (See Attachment 1 – Wicomico County Collector Roads.)
Most of the roads within Wicomico County experiencing nuisance tidal flooding are located in rural areas. The County’s Comprehensive Plan notes that, “The rural road system in Wicomico County provides a critical service to the agricultural community and critical connection between small towns and rural villages to the regional transportation network.”
To address nuisance tidal flooding within Wicomico County, staff from various departments met to review nuisance tidal flooding issues, and to discuss any individual contributing factors and possible mitigation efforts. Members from the Departments of Public Works, Planning and Zoning and Emergency Services were primarily responsible for the creation of this Plan, and will have the responsibility for monitoring future nuisance flooding events and mitigation activities. The team defined different levels of nuisance flooding within the County as follows:
Minor Flooding – Less than 6” of water in the roadway that recedes within 6 to 12 hours
Moderate Flooding – 6” to 2’ of water in the roadway that recedes within 6 to 12 hours
Major Flooding – greater than 2’ of water in the roadway that recedes within 6 to 12 hours
Wicomico County Nuisance Flood Plan – 2020 Page 4
Wicomico County has mostly minor flooding from extreme high tides, with some moderate flooding during lunar events. Major flooding can occur during any weather event that pushes water up the Chesapeake Bay, such as a circulating “nor’easter” storm or a strong south southwest wind. When water levels rise within the Chesapeake Bay, a similar effect is experienced within the Wicomico and Nanticoke Rivers and their tributaries. A positive aspect of tidal flooding is that it recedes within hours of the peak Mariner’s Compass high tide.
III. EFFECT OF SEA LEVEL RISE
Wicomico County has experienced an increase in the number of nuisance tidal events as reported by County staff and citizens living in vulnerable areas. The County lies within an area that is expected to incur a mean sea level rise of between .8 to 1.6 feet by the year 2050 (66% probability). There is a 5% chance it could exceed 2 feet.1 This increase in constant water levels will exacerbate high tides, lunar tides and seasonal extreme high tides, thus increasing nuisance tidal flooding.
The southwestern area of the County and the communities of Nanticoke, Bivalve and Tyaskin, as well as the southern community of Whitehaven are expected to feel the greatest effects of sea level rise. These communities are located on a major waterway and they have numerous tidal tributaries and streams. Increasing their vulnerabilities is the fact that ground elevations in these communities are often at only a few feet above sea level. (See Attachment 2 – Sea Level Rise Inundation of 1 FT and Attachment 3 – Sea Level Rise Inundation of 2 FT.)
These vulnerable communities also have limited roadways for evacuation during moderate to major tidal flooding events. However, as previously mentioned, tidal flooding does routinely recede within a few hours of peak high tide, and roads are usually clear within 6 to 12 hours. Notification of impending extreme high tides to homeowners in these areas is a priority for the Department of Emergency Services.
The Department of Public Works has instituted measures to reduce nuisance tidal flooding on a few roads – which when flooded, prevent travel. These actions are highlighted below in the “Mitigation Efforts” section.
IV. INVENTORY
Several roads were identified as experiencing nuisance tidal flooding based on staff experience and other available tools, including:
Maryland Department of Transportation and State Highway Administration’s Climate Change Vulnerability mapping tool (MDOT SHA) using the 2015 Mean Sea Level - 10% Annual Change (10YR Storm) (See Attachment 4), and the corresponding flood depth grid.
1 “Sea-level rise Projections for Maryland 2018” prepared for the Maryland Commission on Climate Change Act of 2015 Wicomico County Nuisance Flood Plan – 2020 Page 5
Tide charts for Roaring Point (Nanticoke) and Whitehaven available from the Maryland Department of Natural Resources.
Readings from the NOAA/NOS/CO-OPS observed water levels at flood gauge number 8571421 located in Bishops Head, Maryland.
Station BISM2 - 8571421 -
Bishops Head, MD
(Bishops Head shown in yellow)
Using information gathered from these sources, it appears as though nuisance flooding occurs at the following tide depths:
Minor Flooding – approximately 1.5’ to 2.0’ high tide
Moderate Flooding – approximately 2.0’ to 2.8’ high tide
Major Flooding – approximately greater than a 2.8’ high tide
These depths will be refined as monitoring of tidal flooding Cove Road, Tyaskin 2/7/2020 during a strong SSW wind events occurs over the next five years as part of this event at high tide Nuisance Flood Plan. A circulating northeasterly wind from a “nor’easter” storm or from a hurricane, as well as a steady south southwest wind can have a notable influence on the amount of flooding incurred at high tide, increasing the tidal effects. (See Attachment 5 – Effect of Winds on Local Tides.)
The roads identified in this initial plan as experiencing nuisance tidal flooding are shown in the following table.
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Table 1. Roads Identified as Experiencing Nuisance Tidal Flooding
ROAD NAME/FLOOD SOURCE LOCATION OF FLOODING COMMENTS Clara Road, Tyaskin Worse flooding occurs south of Minor collector road. Mitigation Wicomico River and tidal ditches Mezick Road, however, occasional efforts are planned. See additional minor tidal flooding can occur comments in the next section. along the length of Clara Road due to tidal ditches Cove Road, Tyaskin Final approximately 1,000 feet of Minor collector road. Moderate to Nanticoke River the road as it reaches the major flooding can occur during Nanticoke River extreme tidal events Deep Branch Road, Quantico At the bridge Minor collector road. Moderate Tyaskin Creek flooding can occur during extreme tidal events. The road would have to be raised significantly in order to mitigate the flooding. Harbor Drive, Nanticoke Parking lot and road near boat Local road. Minor flooding occurs Nanticoke River ramp in this area from an unprotected beach area and a boat ramp. Muddy Hole Road, Tyaskin Entire length Minor collector. This is primarily an Broad Creek, Muddy Hole Creek, unimproved road running through and various tidal tributaries of the tidal marshlands. A new bridge Wicomico River was built over Broad Creek several years ago, and continued maintenance has only kept the road passable in some areas. No significant improvements are planned due to the lack of residences along this unimproved road. Nanticoke Drive, Nanticoke Near community park and at the Local road. Mitigation efforts have Nanticoke River and tidal ditches end of the cul-de-sac occurred with more planned. See additional comments in the next section. Nanticoke Road, Waterview Several locations near Waterview This is a State road and it is Nanticoke River, tidal ditches and unlikely that mitigation efforts will marshes occur since this road serves only a small number of residences in this section. Riverside Drive, Salisbury Where tidal creek crosses Major collector. Only minor Stock Creek Riverside Drive occasional nuisance flooding. Riverton Road, Riverton Near Old School House Road Minor collector. This area has Nanticoke River and tidal ditches minor flooding on high and lunar tides, and can experience moderate to major flooding during extreme tidal events. There is no bulkhead or rip rap along the Nanticoke River in the area; there is a tidal ditch which runs along the road; and ground elevations are only approximately two to four feet. Town of Whitehaven – Church All three roads in the town flood Whitehaven Rd. is major collector. Street, River Street and repeatedly on high and lunar tides, Other roads are local roads. Whitehaven Road with the worse flooding occurring Mitigation efforts have occurred Wicomico River and tidal ditches on River Street and Whitehaven with more planned. See additional and marshes Road. comments in the next section.
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ROAD NAME/FLOOD SOURCE LOCATION OF FLOODING COMMENTS Trinity Church Road, Tyaskin Various places along the road Minor collector. Raising the road Muddy Hole Creek and tidal may help. This is a rural road ditches serving only a couple residences. Tyaskin Road, Tyaskin Park and Parking Lot at the end of Minor rd. Nuisance flooding occurs Nanticoke River the road occasionally in the park area. Upper Ferry Road, Eden Near the ferry and for about 200 Major collector. The elevation of Wicomico River and tidal ditches feet the road is only about 1.5’ to 2.5’ above sea level and there is a tidal ditch running along the road. With the ferry, elevating the road would be difficult. Wetipquin Road, Tyaskin At the bridge Minor collector. There is minor to Wetipquin Creek moderate flooding occurring on both sides of the bridge from high and lunar tides. The road would have to be raised.
Two of the roads noted above – Upper Ferry Road and Whitehaven Road – lead to ferries providing transportation across the Wicomico River. These routes are used daily by commuters from the west side of Wicomico County who work in Somerset County – especially those working at Eastern Correctional Institution or working or attending the University of Maryland Eastern Shore. They are also popular routes for tourists and bicyclists.
The ferries are vulnerable to high tides and often have to cease operation during peak hours of a higher-than-normal tide. During a 2012 study, it was determined that the two ferries were closed 21 times during a 60 day period due to high tides. The closings are often only for an hour and a half to two hours, but these closings can cause serious headaches for residents depending upon the ferries for travel to work and school. Detours around the ferries are time- consuming.
V. MITIGATION EFFORTS
Clara Road A major flood event on the section of Clara Road in the area of planned work. October 12, This road is identified as a Minor Collector in 2019 the County’s road system. The road serves residences and one seasonal business. That portion of the road south of Mezick Road is the sole evacuation route for the approximately 10 residences and one seasonal business located in that section. The Department of Public Works is planning to clean out the ditches and culverts for the last 2,000 feet of road before it meets the Wicomico River to assist the tidal waters in receding faster. That project is expected to begin in the Fall of 2020. Raising the road may also assist with nuisance tidal flooding. The County will continue to monitor tidal flooding events along this road following the ditch and culvert clean-out project to determine if further mitigation efforts are feasible. Wicomico County Nuisance Flood Plan – 2020 Page 8
Nanticoke Drive This local road runs along the Nanticoke River in the community of “Nanticoke Acres”. There are primarily two areas along the road experiencing minor flooding during high and lunar high tides, with moderate to major flooding occurring during extreme high tides and high wind events. One area is near the community park where a tidal ditch is the primary source of flooding. The other area is at the end of the cul-de-sac where another tidal ditch causes nuisance flooding.
The community park is owned by the Homeowners Association and that group is also responsible for ditch maintenance within the subdivision. The tidal ditch at the park has filled in with silt. Bushes and trees have grown, reducing the ditch’s capacity to allow flood waters to recede back to the Nanticoke River. The Department of Public Works has contacted the Homeowners Association and told them that if they will clean out the ditch along the community park, the County will ditch along Nanticoke Drive and replace failed driveway culverts so tidal waters can flow out to the Nanticoke River quicker. Follow-up contact will be made to ensure that this project occurs. There are two repetitive loss properties which are affected by this tidal ditch so mitigation is a priority.
Tidal ditch at Community Park as waters Water flow in tidal ditch at Community from the Nanticoke River enter the ditch Park is obstructed by silt, bushes and during a strong SSW wind event at high small trees growing in it. SSW wind tide. February 7, 2020 event at high tide February 7, 2020.
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With regards to the tidal ditch at the end of Nanticoke Drive, the County’s Public Works Department has cleaned out the tidal ditch and the pipe which lies between Nanticoke Acres and Roaring Point Campground. This has allowed the water to flow out quicker from the end of Nanticoke Drive and Chesapeake Drive within the subdivision.
Cul-de-sac at the end of Nanticoke Drive during a SSW event at high tide on February 7, 2020 prior to the ditch work described above.
Town of Whitehaven – Church Street, River Street and Whitehaven Road The entire historic town of Whitehaven is vulnerable to tidal flooding from the Wicomico River, tidal ditches to the east and west, as well as the tidal marsh to the east. There is a significant tidal ditch running along Whitehaven Road which has been responsible for minor flooding of that road during high tides, moderate flooding during lunar tides, and major flooding during extreme and storm events.
The entire town was entered in the National Register of Historic Places in 1979. Adding to the charm of this community is a ferry that has been in continuous operation since 1688 or earlier. The ferry ramp provides a source of tidal flooding from the Wicomico River - influencing Whitehaven Road at River Street. Along River Street there are two drainage outlets which backwash with water during high tides, creating minor to moderate flooding. Further down River Street, there is no bulkhead at the intersection with Church Street and the River is able to wash over the narrow land, adding to the backwash from the outlet located nearby.
All three of the town’s roads experience major flooding during extreme tide and storm events. Whitehaven Road is the only access into and out of Whitehaven and it has historically experienced flooding from the tidal ditch running along the easterly side of the road, as well as from the ferry ramp, as previously noted. Evacuation is a concern during storm events.
Recently, the Department of Public Works performed ditch and culvert maintenance in the tidal ditches located along Whitehaven Road near the intersection with Church Street. Flood gates were also placed in the two outlets located along Whitehaven Road in an attempt to reduce the tidal influence from the marshlands and tidal ditch running along the road. In addition, the three major streets within the town were repaved and raised 2 to 3 inches.
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The new flood gates installed along Whitehaven Road have produced positive results and the County anticipates placing flood gates in the outlets along River Street to help reduce tidal flooding.
The Wicomico County Hazard Mitigation Plan lists the town of Whitehaven as a hazard mitigation project. Due to the complexity of the flooding issues, the County contacted the Army Corp of Engineers for assistance. A planning study was completed and a final report was received in September, 2020. Once the report has been reviewed by County officials, a meeting with the town’s residents will be held to discuss possible courses of action to reduce flooding within Whitehaven.
Long-time citizens of Whitehaven, who were interviewed during the course of the Army Corp project, indicated that nuisance tidal flooding occurs much more often than they remembered as young adults or when they first moved to the town.
Mitigation efforts are necessary in order to protect this historic town and ferry from rising sea levels and increased tidal events. There are repetitive loss properties within Whitehaven so mitigation is a priority.
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Town of Whitehaven
Whitehaven Road at Church Street on February 7, 2020. The newly installed A look toward the Whitehaven Ferry flood gates could not withstand this during a moderate to major flooding type of high tide event even though they event on February 7, 2020 caused by a have helped with typical high tides. strong SSW wind event. The ferry lies idle due to the extreme high tide.
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VI. MONITORING AND RESPONDING TO TIDAL FLOODING EVENTS
The monitoring of future nuisance tidal events will be a joint effort between the Departments of Public Works, Planning and Zoning and Emergency Services over the next five years (2020 to 2025) when this Nuisance Flood Plan will be revised and updated. Methods will include:
1. Using the Tide Predictions published by the Maryland Department of Natural Resources, NOAA’s Advanced Hydrologic Prediction Service graphs, and notices received by the Department of Emergency Services, staff from the Departments of Emergency Services, Public Works and Planning and Zoning will begin documenting nuisance tidal events. This data can then be periodically compared to the actual readings by NOAA at the tidal gauge located at Bishops Head to gain a more accurate account of tide depth causing minor, moderate and major nuisance tidal flooding.
2. Once it is available, we will be utilizing the new tool being developed by the Maryland Department of Natural Resources to document nuisance flood events.
3. Educating the public to act as “citizen reporters”.
The Department of Public Works will monitor road conditions and, when appropriate, place high water signs and re-route traffic if flooding reaches hazardous levels. The Department of Emergency Services will alert the public to impending nuisance tidal flooding issues via social media and other means outlined in the Wicomico County Emergency Operations Plan.
The Department of Emergency Services has developed tiered evacuation zones within Wicomico County to ensure the safety of its citizens during tropical storms, hurricanes and tidal flooding events. (See Attachment 6 – Evacuation Zones.) Ongoing community education will enhance public alert and evacuation plans.
Wicomico County will continue to address nuisance tidal flooding by concentrating on individual areas identified as being vulnerable to tidal influences. As solutions become apparent, the County will seek sources of funding to assist in the completion of these projects.
Addressing nuisance tidal flooding issues provides a dual purpose of environmental protection. Receding high tide flood waters often contain pollution from the roads, chemicals from maintained yards, and roadside trash and debris. One of the goals of the Wicomico County Comprehensive Plan is to “Protect, restore, and enhance the water quality of Wicomico County’s tidal and non-tidal waterbodies”. This Nuisance Flood Plan, and the continued work to reduce tidal flooding, will help to meet that goal.
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ATTACHMENT 1 – COLLECTOR ROADS
ATTACHMENT 2
ONE FOOT SEA LEVEL RISE OF MOST VULNERABLE AREAS – Page 1 of 2 (Source: NOAA Sea Level Rise Viewer)
NANTICOKE – 1 FT SEA LEVEL RISE
BIVALVE AND TYASKIN – 1 FT SEA LEVEL RISE
ATTACHMENT 2
ONE FOOT SEA LEVEL RISE OF MOST VULNERABLE AREAS – Page 2 of 2 (Source: NOAA Sea Level Rise Viewer)
WHITEHAVEN – 1 FT SEA LEVEL RISE
ATTACHMENT 3
TWO FOOT SEA LEVEL RISE OF MOST VULNERABLE AREAS – Page 1 of 2 (Source: NOAA Sea Level Rise Viewer)
NANTICOKE – 2 FT SEA LEVEL RISE
BIVALVE AND TYASKIN – 2 FT SEA LEVEL RISE
ATTACHMENT 3
TWO FOOT SEA LEVEL RISE OF MOST VULNERABLE AREAS – Page 2 of 2 (Source: NOAA Sea Level Rise Viewer)
WHITEHAVEN – 2 FT SEA LEVEL RISE
A 3 FT Sea Level Rise is expected to inundate the town of Whitehaven
ATTACHMENT 4
Maryland Department of Transportation and State Highway Administration Climate Change Vulnerability Map
MDOT SHA Map showing 2015 Mean Sea Level 10% Annual Change (10-Year Storm) with the Nuisance Flood Mapping overlay
ATTACHMENT 5
Effect of Winds on Local Tides – Page 1 of 3 February 7, 2020
On February 7, 2020, a steady, strong south then south southwest wind blew during the hours leading up and during high tide. The effect was moderate to major tidal flooding throughout Wicomico County. WeatherUnderground recorded wind gusts of up to 54 mph during the incoming high tide which crested shortly after Noon at Roaring Point on the Nanticoke River and about a half hour later in Whitehaven on the Wicomico River. The NOAA “Verified” tide height was only approximately 2 feet at the Bishops Head, MD tidal gauge, but the effects of the strong SSW wind resulted in more significant flooding than tide predictions anticipated.
NOAA BISHOPS HEAD, MD MARKER Settings: February 7, 2020, Time Zone LST/LDT, MHW
Home on Nanticoke Dr., Nanticoke with water rushing in yard
Feb. 7, 2020
River Street in Whitehaven – Feb. 7, 2020 Historic Schoolhouse at the corner of Whitehaven Road and Church Street, Whitehaven – Feb. 7, 2020
ATTACHMENT 5
Effect of Winds on Local Tides – Page 2 of 3 August 4, 2020
NOAA BISHOPS HEAD, MD MARKER Settings: August 4, 2020, Time Zone LST/LDT, MHW Clara Road, Tyaskin - 1:47 p.m. Tides at Clara Road are usually about an hour later than the Bishops Head marker. Major flooding occurred August 4, 2020 with over a 3.5 foot high tide.
On August 3 and 4, 2020, the Delmarva Peninsula suffered the effects of Hurricane Isaias which caused circulating northeasterly winds coupled with a short-term heavy rainfall. As the skies cleared, the storm’s effect continued to cause higher-than-predicted tides as the swollen Chesapeake Bay pushed water into its tributaries. As evidenced by the blue “Predictions” line above on the NOAA chart and the Maryland DNR predicted tide chart for Whitehaven, actual NOAA “Verified” tides were much higher due to the strong wind influence.
ATTACHMENT 5
Effect of Winds on Local Tides – Page 3 of 3 September 21, 2020
Clara Road - 6:51 p.m. Tides at Clara Road are usually about an hour later than the Bishops Head marker. Minor to moderate flooding at Steeles Neck Road.
NOAA BISHOPS HEAD, MD MARKER Settings: September 21, 2020, Time Zone LST/LDT, MHW
On September 21, 2020, Hurricane Teddy was circulating in the Atlantic Ocean off the Delmarva Peninsula. Moderate flooding occurred in Wicomico County due to higher tides from the storm’s circulating northeasterly winds and the influence on the waterways. “Verified” NOAA tide heights were not available as of the publication of this Nuisance Flood Plan.
Clara Road - 6:51 p.m. Moderate flooding looking toward Wicomico River.
ATTACHMENT 6 Evacuation Zones