Basement Flooding

Flooding Issues in Cleveland Suburbs

Rainfall Map for Solon and Cleveland Suburbs

Rainfall Map for Solon Cleveland Suburbs-Click to enlarge

Click to enlarge this rainfall map of the June 22-24, 2006 storm. This massive storm event caused some flooding issues in Broadview Heights, Brecksville, Solon, Sagamore Hills, Bainbridge, Twinsburg, Independence, Glenwillow, Oakwood, Bedford, Garfield Heights, Valley View etc.

100 Year Storm: A storm of a certain intensity and length of time that has a 1% probability of occuring each and every year.

500-1000 Year Storm: The June 22-24, 2006 storm poured 5.5″ of rainfall over a 4 hour period. This storm damaged approximately 4, 580 homes and 48 businesses in Cuyahoga County.

What you need to know is that a typical stormwater collection system is designed for a 5 year to a 25 year storm!

Flooding in Brecksville

Reference: Flood of June 22-24, 2006, in North Central Ohio with Emphasis on the Cuyahoga River Near Independence By James M. Sherwood, Andrew D. Ebner, G. F. Koltun and Brian M. Astifan, Scientific Investigations Report 2007-5161, USGS and FEMA.

Does your home need a backwater valve?

City of Solon Flood Zones Map-Real Estate in City of Solon

City of Solon Flood Zones Map-Click to enlarge

FEMA FLOOD ZONE DESIGNATIONS & EXPLANATIONS

Annual Probability of Flooding of 1% or greater

A Subject to 100-year flood. Base flood elevation undetermined.

AE or A1-A30 Both AE and A1-A30 represent areas subject to 100-year flood with base flood elevation determined.

AH Subject to 100-year shallow flooding (usually areas of poundings) with average depth of 1-3 feet. Base flood elevation determined.

AO Subject to 100-year shallow flooding (usually sheet flow on sloping terrain) with average depth of 1-3 feet. Base flood elevation undetermined.

A99 Subject to 100-year flood, with federal flood protection system (levee/dam) under construction. Base flood elevation undetermined.

V Subject to 100-year flood and additional velocity hazard (wave action). Base flood elevation undetermined.

VE or V1-V30 Both VE and V1-V30 represent areas subject to 100-year flood and additional velocity hazard (wave action). Base flood elevation determined.

In SFHA Areas in a “Special Flood Hazard Area” (or 100-year flood plain). Subject to 1% annual chance flooding. No distinctions have been made between the different flood hazard zones that may be included within the SFHA.

Flood Prone Area: An area designated as a “Flood Prone Area” on a map prepared by USGS and the Federal Insurance Administration. This area has been delineated based on available information on past floods. This is an area inundated by 1% annual chance flooding for which no base flood elevations have been determined.

Annual Probability of Flooding of 0.2% to 1%

B or X500 Both B and X500 represent areas between the limits of the 100-year and 500-year flood; or certain areas subject to 100-year flood with average depths less than 1 foot or where the contributing drainage area is less than 1 square mile; or areas protected by levees from the 100-year flood.

Annual Probability of Flooding of Less than 0.2%

C or X Both C and X represent areas outside the 500-year flood plain with less than 0.2% annual probability of flooding.

Annual Probability of Flooding of Less than 1%

No SFHA Areas outside a “Special Flood Hazard Area” (or 100-year flood plain). Can include areas inundated by 0.2% annual chance flooding; areas inundated by 1% annual chance flooding with average depths of less than 1 foot or with drainage areas less than 1 square mile; areas protected by levees from 1% annual chance flooding; or areas outside the 1% and 0.2% annual chance floodplains.

Undetermined

D Unstudied areas. Flood hazards are undetermined.

The revised and most current flood zones are available with FEMA.

Source: The helpful City of Solon GIS Coordinator, Tim Howard.

City of Solon Ohio Basement Flooding Map

Basement flooding, wet basements and backwater valve

Lower basement drains may need a backwater valve to prevent basement flooding. Source: Unknown

Basement fixtures may need backwater valve-City of Worcester

Basement fixtures below red line may need backwater valve to prevent basement flooding-Source: City of Worcester

Click on the backwater valve graphics to enlarge them.

What is a Backwater Valve?

Backwater valves are installed to prevent or reduce the frequency of sanitary and storm water backing up on the mainline through the lateral and flooding a basement. This backing up condition is referred to as backflow. Backflow can occur due to 1. obstruction and/or 2. the collection system reaching its capacity.

Who may need a Backwater Valve?

If your home is located on a sloping street and your home is at a lower level than other homes on that street, you may be subject to backflow. Folks who are considering a home purchase on a sloped street should carefully look into this location location location consideration, if feasible, in concert with an appropriate expert such as a plumber, home inspector. Further, the best backwater valves and the backwater valve monitoring system are not inexpensive. The above graphics, obtained from public sources, indicate a few configurations where backflow may be expected.

Backwater Valve Location

The location of plumbing fixtures in the basement does not always indicate the need for a backwater valve, unless these fixtures drain to the mainline by gravity. In instances, where basement drains are pumped up to a upper drain and the pump outlet is provided with a check valve, a backwater valve may not be needed.

The backwater valve should be properly located and installed. The backwater valve is installed as shown in the second figure from the top. The backwater valve should be located upstream of the foundation drains or downspouts connected to the laterals, otherwise the homeowners may flood themselves. Also the backwater valves should impact the basement drain only. Homeowners should always consult an appropriate expert.

Backwater Valve Permit

You may need a permit from your local municipality to install a backwater valve. I think municipal permitting becomes necessary because an improper installation of a backwater valve could push the backflow into a neighboring basement that did not previously was not subject to backflow. I reckon there could be instances where residents have installed backwater valves without obtaining a necessary permit; after all, enforcement resources are not unlimited. Sometimes people blame their local municipality for their basement and residential flooding problems and this is often without a sound and sufficient reasoning.

Other Backwater Valve Considerations

In some instances, basement floor drains may be connected to the municipal stormwater collection system. This isn’t kosher, within the context of the Clean Water Act and the NPDES Phase 2 Storm Water Program; the basement floor drains should be connected to the municipal sanitary sewer collection system.

The backwater valve is imperfect. Its prudent to consider avoiding buying a home that is located on a lower level than other homes on a sloping street. Basements can be versatile additions to a residential property, particularly in north and northeastern parts of the country. A basement can have multipurpose utility, however, installing drains in a basement may lead to complicated conditions, in some cases. Its a bit unlikely that you will hear this from your real estate agent. It would also be fair to expect that location and properties that are prone to flooding due to a gravity challenged location might be subject to higher home insurance rates. Further, it would be reasonable to expect that properties that have resulted in multiple requests for reimbursements for flooding damage are likely to be flagged.

Does your home need a Backwater Valve? Source: Town of Las Gatos, California

Sub-Watershed Map of City of Solon

Solon Sub Ohio Sub-Watersheds Map

This sub-watershed map of City of Solon was on display at the City of Solon Service Department’s Earth Day celebration.

Related Post: City of Solon Subdivisions Map

Earth Day celebration in City of Solon

Free food at Earth Day at Solon Community Center

Earth Day celebration at Solon Community Park

City of Solon Service Department Truck

Sewer Camera?

City of Solon’s Earth Day celebration at the Solon Community Park was a home run. Folks were lining up for mulch and the paper shredder. Perfect weather, free food, bad day for Debbie Downer.

The picture is that of City of Solon’s sewer camera truck, I think. I think the City of Solon has allocated significant resources and has made significant progress in mitigating stormwater flooding and sewer backup issues since the June 2006 flood.

If you are considering buying a home in an area that is prone to basement flooding, it may be worth it to find out if the property has an existing backwater valve or needs a backwater valve. The better backwater valves are not inexpensive.

One would think that real estate agents would be obligated under their fiduciary responsibility to give potential home buyers hints about significant and publicized events like the major flood events. Further, some homeowners insurance policy may require that the property must have a backwater valve to be covered against flooding due to sewer backups.

Backwater Valve

Flooding Issues in Cleveland Suburbs