📍 Westerville, OH — Serving Central Ohio · Mon–Fri 9:00–4:30 Lifetime Leak-Free Guarantee
The Open Shower Co. — walk-in showers and bath remodeling
(614) 423-9766 Build Your Price
Ohio building history, hazards and the rules

Central Ohio floods, and the dams, levees and floodwalls built after them

Central Ohio's flood record is kept by several agencies that do not always agree, and this page prints it the way they wrote it. January 1959 is the record crest on the National Weather Service's list for the Columbus gage; the March 1913 flood is not on that list at all; and the three reservoir dams most people can see from a road are drinking water dams the city itself says were not built to hold a flood back. The page sets out the crests with their gages, the dams and lakes with the acts that authorized them, the Franklinton floodwall with its authorizing statute, the flood maps by their dates, and the plumbing code sections a bathroom below the sewer meets.

Last updated September 2026 · Gage records, the Geological Survey's Circular 418 of 1959, the Corps of Engineers' project pages, Ohio's dam inventory and rules, and the Federal Emergency Management Agency's flood studies and status book were read September 2026 · No prices on this page; the Estimate Builder carries those · Part of the knowledge base

What this page records, and what it leaves out

Every crest, discharge, dam figure and date below appears once, with the gage or the dam named and the agency that published it, and where two agencies give one structure different figures both print. Two kinds of record were read and deliberately kept off: any assessment of the condition of a named dam, levee or floodwall, and any statement of which streets flood at a given river stage. Nothing here says what to do about a river, dam or map.

Flood zones, and the code's flood-resistant construction section, are on the page about what goes wrong in a Central Ohio house. The 1913 flood in Franklinton, and the floodwall's outline, are on the Franklinton page; the Conservancy Act of Ohio is on the incidents page.

The gage record: what crested where, and when

The National Weather Service's Columbus gage is the one it calls Scioto River at Frank Road, reading the U.S. Geological Survey's station 03227500. Its highest crest is 27.22 feet on January 22, 1959, at 68,200 cubic feet per second, and the Geological Survey's Circular 418 of 1959 gives the same pair from a high-water mark.

Gage, in the Weather Service's own nameHighest crest the Service listsDateFlood categories, in feet
Scioto River at Frank Road27.22 feet, 68,200 cubic feet per secondJanuary 22, 195916, 24, 25 and 27
Olentangy River near Worthington15.68 feet, 16,500 cubic feet per secondJanuary 21, 19598, 11, 13 and 15
Scioto River near Dublin24.6 feetMarch 25, 1913none published
Alum Creek at Columbusnone publishednone publishednone published
Big Walnut Creek at Reesnone publishednone publishednone published

The last two rows are a finding, not a gap in the reading: the Service's records for Alum Creek at Columbus and Big Walnut Creek at Rees come back complete but hold no historic crest list and no flood category, so the crest record for the two creeks that ran highest on the east side of Columbus in 1959 has to come from the Geological Survey. Below O'Shaughnessy Dam near Dublin, the Service's own crest list has 1913 as the highest crest and 1959 second.

Why 1913 and 1959 cannot be ranked against each other at Columbus

The Service's crest list for the Frank Road gage holds 58 crests and its earliest is March 29, 1921. The March 1913 flood is not on it. The Geological Survey's annual peak file for the same station does list March 25, 1913, at 138,000 cubic feet per second, and flags it in its own legend as an estimate, as affected by regulation or diversion, and as a historic peak.

Circular 418 supplies both a stage and a warning. It says the maximum stage previously known at that station was 25.9 feet on March 25, 1913, and adds that this stage is not comparable with present gage heights, because of later channel improvement and levee construction. The Federal Emergency Management Agency's flood insurance study for Franklin County says the same from the other side: the Columbus gage was not at its present location in 1913.

So 27.22 feet is the highest crest on the Service's Columbus list, which is a different statement from the highest water Columbus has seen. The Geological Survey's summary is that the 1959 floods were generally second only to the 1913 flood throughout a large part of Ohio, and that at several points the 1959 peaks exceeded those of 1913.

January 1959, and the creeks on the east side

Circular 418 says a levee along Dry Run, a small tributary of the Scioto River, was overtopped by the flood waters of the river, releasing water into the west side of the city, while Alum and Big Walnut Creeks in the eastern part of the city were at unprecedented stages. It says gas service at Columbus was interrupted for several days because of water in the lines; how a Central Ohio house came to be heated by that gas is on the heating page.

The Geological Survey puts the January 22, 1959 peak at Big Walnut Creek at Rees at 59,800 cubic feet per second and 22.03 feet, and says the maximum stage known there before 1959 was 20.5 feet on March 25, 1913. The Federal Emergency Management Agency gives the flood of record for Alum Creek in the Columbus area as the same day, at 752.6 feet in the 1988 vertical datum, at the Livingston Avenue gage. Those creeks are on the Linden page and the Gahanna page.

The city's three dams are drinking water dams

The City of Columbus says it plainly in its own brochure: its reservoirs were built for drinking water storage and not flood control. The Federal Emergency Management Agency's Franklin County study says the same of Hoover from the regulator's side, that because this is a water supply dam it is not recognized as providing flood protection. Circular 418 had already said as much of the 1959 flood: the city's three water-supply reservoirs had slight controlling effect, because their design did not include flood storage capacities.

The dates are less settled. The city's two accounts of Griggs Dam disagree: its water supply timeline says construction began in 1904 and dates the dedication to 1908, while its reservoirs brochure says the reservoir was put into service in 1905, the year the Corps of Engineers' National Inventory of Dams also records as completed. Both city publications date O'Shaughnessy Reservoir to 1925, while that inventory records the year completed as 1924 and the 2009 edition of the Delaware County flood study says the Olentangy record has been affected by storage in O'Shaughnessy Reservoir since November 1924.

Hoover Dam on Big Walnut Creek is the hardest to date: four government records give four different years. The city's timeline says 1953, the Federal Emergency Management Agency's Franklin County study 1954, the city's brochure 1955 and the National Inventory of Dams 1956, and two of those four are the same publisher. One date is not in dispute. The Geological Survey records that flow at the Rees gage has been regulated by Hoover Reservoir since September 1954, and that Columbus began diverting water above that gage for part of its municipal supply on June 15, 1956. Ohio's own dam safety inventory carries Griggs and Hoover as class I structures.

The federal lakes, and the acts behind them

The Corps of Engineers says Delaware Lake was authorized by the Flood Control Act of 1938 and that its Huntington District constructed the project between 1947 and 1951. The same Corps page also says dam construction was completed in July 1948, and the Federal Emergency Management Agency says construction was initiated in 1946 and completed in 1951. The 2009 edition of the Delaware County flood study gives operational dates instead: flow was regulated by temporary storage in Delaware Reservoir from October 1947 to March 1951, and completely regulated after March 1951.

The Corps says Alum Creek Lake was authorized by Congress in the Flood Control Act of 1962 and built to reduce the flood hazard along Alum and Big Walnut Creeks, the Scioto River and the Ohio River. Its completion year is not agreed, and two flood studies of one agency disagree about it: the National Inventory of Dams records 1974, the Federal Emergency Management Agency's Franklin County study says the dam was completed in 1964, and that agency's Delaware County study, the one in force for the county the dam stands in, says construction was completed in 1975. The city's timeline adds a fourth date of another kind, that Columbus joined a cooperative agreement with the Corps to build Alum Creek Reservoir in 1971.

The Corps says Deer Creek Lake was authorized through the same 1938 act and that its dam's construction began in 1965 and was completed in 1968, the National Inventory of Dams' year too. It says Congress authorized Paint Creek Lake in that act as well, describes that dam as 118 feet high and 800 feet long, and says it began construction in 1967 and completed the dam and recreation facility in 1974, while its own National Inventory of Dams records the year completed as 1973.

The floodwall, the levees and the low dams downtown

Congress authorized the Franklinton floodwall in the Water Resources Development Act of 1988, which lists the project for flood control, Scioto River, West Columbus, Ohio, on the report of the Chief of Engineers dated February 9, 1988. A Corps draft environmental assessment of March 2017 says the protection extends approximately 2,400 feet along the lower right descending bank of Dry Run and continues from that creek's mouth along the right descending bank and floodplain of the Scioto River for about 7.2 miles. The Federal Emergency Management Agency's Franklin County study calls the same works the West Columbus Local Protection Project, also known as the Franklinton Floodwall, gives the line as a 7.25-mile floodwall and levee along the west bank, and certifies its completion on April 4, 2003. Only the Corps counts the Dry Run leg, and no Corps document read here says when the wall was built or finished.

Downtown, Ohio's dam safety inventory carries the Fifth Avenue Low Head Dam and the Rich Street Low Head Dam, both owned by the City of Columbus, as abandoned structures, 8 feet and 13.5 feet high. The Franklin County study, revised June 16, 2011, still describes a low water dam below the railroad bridge and a low water dam between Main and Broad Streets and says these projects have a minimal effect upon flooding conditions; it was written before either came out.

The Ohio Environmental Protection Agency carries both removals on its own list of Section 319 projects, each with 2014 as the year completed: the Lower Olentangy River 5th Ave. Dam Removal and Stream Restoration, sponsored by the Columbus Public Utilities Department, and the Scioto Greenways Main Street Dam Removal, sponsored by the Columbus Downtown Development Corporation, which the agency says successfully removed the Main Street Dam. Year Completed is that column's own heading, and the year belongs to the grant project, not to the day either dam came out; no record read here gives a demolition date or says what either removal did to flood levels. Nor do the agencies use one name for it: the state environmental agency calls it the Main Street Dam, the state's dam inventory lists only Rich Street, and the flood study describes a low water dam between Main and Broad Streets. No document read here says any two of those names are one structure.

Ohio's dam classes, and the maps that govern an address

Ohio's rule on the classification of dams, rule 1501:21-13-01 of the Ohio Administrative Code, has been in force since June 27, 2024 and carries prior effective dates going back to April 15, 1972. It says dams are to be divided into four classes, class I beginning at a total storage volume greater than five thousand acre-feet or a height greater than sixty feet, with three smaller classes below it and a downstream-hazard limb that can raise a smaller dam's class. The Ohio Department of Natural Resources' Division of Water Resources says the system was modeled after the Federal Guidelines for Dam Safety established in 1979, and its fact sheet adds the sentence a reader needs beside every class above: the classification is not an indication of the condition of a dam.

The Division regulates class I, class II and class III dams that are not federally owned; its locator held 7,180 dams in Ohio on September 7, 2026, 413 of them class I, 39 of those in the seven Central Ohio counties. The Corps of Engineers' National Inventory of Dams carries 126 dams in those same counties on a different scale, hazard potential rather than class, with 39 rated high; the two scales are not the same and should not be read across.

The map that governs an address is another record again. By the Federal Emergency Management Agency's Community Status Book for Ohio, reported February 4, 2025, the City of Columbus had its first flood hazard boundary map identified on August 9, 1974, entered the regular program and had its first flood insurance rate map on July 5, 1983, and runs today on a map dated June 16, 2011, which unincorporated Franklin County shares. Most Franklin County suburbs are on an older map and the outlying counties on newer ones; the questions below give those dates.

What the plumbing code asks below the sewer

The rule is not where a reader would look. The Residential Code of Ohio has no plumbing drainage chapter: its section 2501.1 says the provisions of the Ohio Plumbing Code shall be incorporated and shall govern the plumbing in buildings within the code's scope. They sit instead in the Ohio Plumbing Code, rule 4101:3-7-01 of the Ohio Administrative Code, which modifies chapter 7 of the 2021 International Plumbing Code and is in force from October 15, 2025, with prior effective dates back to March 1, 1998. Which building rules were in force in which Central Ohio jurisdiction is on the page about which code a house was built under.

Ohio rewrote section 714.1, the backwater valve section. As Ohio prints it, a backwater valve is to be installed only if the Ohio Environmental Protection Agency or the local sewer purveyor requires one, and then only for plumbing fixtures on a floor whose finished floor elevation is below the elevation of the manhole cover of the next upstream manhole in the public sewer; fixtures above that elevation must not discharge through one, with an exception for existing buildings. Section 712 is the sump and ejector section, and Ohio adds an exception to section 712.2: in buildings where the Residential Code of Ohio applies, only a check valve is required, located on the discharge piping from the sewage pump or ejector.

Neither section tells a homeowner what to do, and neither does this page. What a sump may and may not discharge into is on the Columbus sewers page and the sewer lateral page, and the circuit a pump sits on belongs with the wiring a house of each era carries. In the Franklin County Auditor's record of August 15, 2026, 62.83 percent of the county's single-family houses carry the basement value FULL BASEMENT.

The short version. The Weather Service's Columbus crest list begins in 1921 and holds no 1913 entry, so its record crest, set in January 1959, is the highest on that list rather than the highest water the city has seen. Griggs, O'Shaughnessy and Hoover are drinking water dams by the city's own statement; Delaware, Alum Creek, Deer Creek and Paint Creek are the federal flood-control lakes.

Sources

Every figure, date and quotation on this page comes from one of these documents, read on the date given. Where two of them disagree, the page says so.

Common questions

What is the highest crest on record for the Scioto River at Columbus?

The National Weather Service's Columbus gage is the one it calls Scioto River at Frank Road, and its highest crest is 27.22 feet on January 22, 1959, at 68,200 cubic feet per second. The Geological Survey's Circular 418 gives the same pair from a high-water mark. Read that carefully, because the Service's crest list for that gage begins on March 29, 1921 and holds no 1913 entry, so 27.22 feet is the highest crest on that list rather than the highest water Columbus has seen. The Service's four flood category stages there are 16, 24, 25 and 27 feet.

Why is the 1913 flood missing from the river gage record at Columbus?

Because the record was not being kept in the same place. The National Weather Service's crest list for the Scioto River at Frank Road begins in March 1921. The Geological Survey's annual peak file for the same station does carry March 25, 1913 at 138,000 cubic feet per second, flagged as an estimate, as affected by regulation and as a historic peak, and its Circular 418 gives the 1913 stage there as 25.9 feet while warning that the stage is not comparable with present gage heights after later channel improvement and levee construction. The Federal Emergency Management Agency says the Columbus gage was not at its present location in 1913.

Were the Columbus reservoirs built to control floods?

No, and the City of Columbus says so itself. Its own brochure about its reservoirs says they were built for drinking water storage and not flood control, and the Federal Emergency Management Agency's Franklin County flood study says that because Hoover is a water supply dam it is not recognized as providing flood protection. The city adds that its in-stream reservoirs were designed so that excess water spills over the dams to the waterway below, and that at Hoover there is a limited amount of control by lowering and raising gates at the dam, but only by a few feet.

When was Hoover Dam on Big Walnut Creek built?

Four government records give four different years, and two of them come from the same publisher. The City of Columbus water supply timeline says 1953, the Federal Emergency Management Agency's Franklin County flood study says 1954, the city's reservoirs brochure says 1955, and the National Inventory of Dams says 1956. One date is not in dispute. The Geological Survey records that flow at the Big Walnut Creek gage at Rees has been regulated by Hoover Reservoir since September 1954, and that Columbus began diverting water above that gage for part of its municipal supply on June 15, 1956.

Which dams near Columbus were actually built for flood control?

The federal ones. The Army Corps of Engineers says Delaware Lake and Deer Creek Lake were authorized by the Flood Control Act of 1938, and that Alum Creek Lake was authorized by Congress in the Flood Control Act of 1962 and built to reduce the flood hazard along Alum and Big Walnut Creeks, the Scioto River and the Ohio River. The Corps also says a 1962 congressional study of the Scioto basin led to the multi-purpose dams on Alum Creek, Deer Creek and Paint Creek. Griggs, O'Shaughnessy and Hoover are the city's drinking water dams instead.

How old are the flood maps for Columbus and the Central Ohio counties?

They are neither one map nor one date. By the Federal Emergency Management Agency's Community Status Book for Ohio, reported February 4, 2025, the City of Columbus and unincorporated Franklin County run on a current effective map dated June 16, 2011, while Bexley, Dublin, Gahanna, Grandview Heights, Grove City, Hilliard, Upper Arlington, Westerville, Worthington, Canal Winchester and New Albany all carry June 17, 2008. Delaware County is on December 21, 2023, Union County September 21, 2023, Madison County November 16, 2023, Fairfield County April 25, 2024, Licking County July 31, 2024 and Pickaway County July 22, 2010.

Does a class I dam in Ohio mean the dam is in poor condition?

No. Ohio's rule on the classification of dams, rule 1501:21-13-01 of the Ohio Administrative Code, sorts dams by size and by what lies downstream: class I begins at a total storage volume greater than five thousand acre-feet or a height greater than sixty feet, with a downstream-hazard limb that can raise a smaller dam's class. The Ohio Department of Natural Resources' Division of Water Resources states the point directly in its own fact sheet, saying the classification is not an indication of the condition of a dam. The Division regulates class I, class II and class III dams that are not federally owned.

What does Ohio plumbing code section 714.1 say about backwater valves?

Ohio rewrote that section. As Ohio prints it in rule 4101:3-7-01 of the Ohio Administrative Code, in force from October 15, 2025, a backwater valve is to be installed only if the Ohio Environmental Protection Agency or the local sewer purveyor requires one, and then only for plumbing fixtures on a floor whose finished floor elevation is below the elevation of the manhole cover of the next upstream manhole in the public sewer. Fixtures above that elevation must not discharge through one, with an exception for existing buildings. The Residential Code of Ohio has no drainage chapter and incorporates the plumbing code instead.

See your actual price in about two minutes

Pick your shower, choose real products with real model numbers, and watch the number move. No phone number required, and nobody will call unless you ask.

Build Your Estimate Call (614) 423-9766