The Great Flood of 1913
100 Years Later

Rainfall & Hydrology

Rainfall  |  Hydrology  |  Recurrence  |  Stream Gaging

Highest Recorded Rainfall Observations for the month of March 1913
Source:MRCC
State	City/Town	Amount (in)
IN	SHOALS 5 S	14.49
OH	KILLBUCK	13.51
IN	BLOOMINGTON IND UN	13.03
IN	VINCENNES 4 E	12.95
IN	RICHMOND WTR WKS	12.89
OH	MARION	12.58
OH	PIQUA	12.43
IN	BUTLERVILLE	12.36
OH	UPPER SANDUSKY	12.29
OH	BELLEFONTAINE	12.27
IN	SALAMONIA	12.20
IN	CONNERSVILLE	12.14
IN	MAUZY	12.08
IN	RUSHVILLE	12.08
IN	COLUMBUS	12.01
IN	WASHINGTON 1 W	11.99
IN	CAMBRIDGE CITY 3 N	11.80
IN	NASHVILLE 2 NNE	11.69
IN	HUNTINGBURG AP	11.56
OH	GREENVILLE WTP	11.51
IN	FARMLAND 5 NNW	11.12
OH	AKRON FULTON INTL AP	10.89
OH	HUDSON	10.82
IN	SEYMOUR 2 N	10.82
OH	GARRETTSVILLE	10.80
IN	HENRYVILLE STATE FOR	10.80
OH	NORWALK WWTP	10.70
OH	SIDNEY 2 N	10.66
OH	URBANA WWTP	10.53
IN	PRINCETON 1 W	10.49
IN	HICKORY HILL	10.47
OH	BUCYRUS	10.40
OH	OBERLIN	10.38
OH	CHIPPEWA LAKE	10.36
OH	DAYTON MCD	10.36
IN	MARION 2 N	10.31
OH	KINGS MILLS	10.24
OH	TIFFIN	10.23
IN	PAOLI	10.23
IN	MADISON SEWAGE PLT	10.17
IN	WORTHINGTON	10.13
IN	WORTHINGTON	10.13
OH	WAPAKONETA (1)	10.10
IN	SCOTTSBURG	10.04
OH	LIMA WWTP	10.01

RAINFALL

Why did so much rain fall over such a large area and for such a lengthy period?

The placement of an area of high pressure off the eastern seaboard was the mitigating factor in the on slot of rain that fell over the Ohio Valley. This feature became “blocked” or nearly stationary for days. At the same time, an upper level trough over the Rockies also stalled. This feature supported the development of a series of surface lows over Colorado.  Each of these low-pressure systems tracked directly into the Ohio Valley as they moved east. The presence of the high off the east coast slowed the advancement of each low. Meanwhile, the air moving into the region was being pulled from the Gulf of Mexico. Strong low level winds pulled this moist air right up the through the Mississippi River Valley and into Ohio. This pattern changed very little over the four days resulting in widespread heavy rain over the entire Ohio Valley.

Does a 100-year storm always cause a 100-year flood?

No. Several factors can independently influence the cause-and-effect relation between rainfall and streamflow.

The Rainfall - Maps and Amounts

The map above depicts the return frequency of the rainfall that fell during the Great Flood of 1913 event. A large swath shows a <0.1% chance, which equates to a greater than 1 in 1,000 year rain event. Map courtesy of NOAA NWS Office of Hydrologic Development.

MARCH 1913:	Greatest amount in consecutive 24 hours					Short Duration Measured Rainfall
Site	Amount (inches)	Duration (hh:mm)	Date Started	Date Ended		Date	From	To	Duration	Amount (inches)
Dayton, OH	4.40	24:00	24	25		24	6:40 AM	8:55 PM	14:15	2.84
Dayton, OH	5.00	25:26	24	25
Dayton, OH	2.84	14:15	24	24
Terra Haute, IN	2.90	24:00	24	25
Evansville, IN	4.01	24:00	24	25
Cleveland, OH	3.17	18:58	24	25
Pittsburgh, PA	1.83	24:00	25	26
Cincinnati, OH	4.32	22:41	25	26		26	18:05	19:05	1:00	1.15
Louisville, KY	5.13	17:38	25	26		25			0:28	1.05
Louisville, KY	1.05	00:28	25	25
Fort Wayne, IN	2.76	24:00	23	24
Columbus, OH	3.22	22:06	25	26

Source: Weather Bureau Climate Station Archives

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HYDROLOGY

How much of the rain that fell during the March 1913 storm become runoff? Ordinarily, only a fraction of the rainfall hitting the ground is able to run off into the nearest river. Many things from ground cover, soil type, temperature, snowpack, and vegetation can affect runoff efficiency. The main factors that can produce catastrophic floods are a combination of rainfall intensity, storm size, storm duration, and antecedent ground conditions. The Great Flood of 1913 had a near perfect scenario for the development of a historic flood.

Ground Cover

Ground cover in winter and spring lacks the vegetation that typically absorbs a significant amount of rainfall, or tree coverage that intercepts the rain before reaching the ground. The winter and spring flood risks are increased by the fact that the ground is often frozen, or snow packs exist that can melt and contribute to the total runoff.  By late March of 1913, the topsoil had experienced a recent thaw and there was no snowpack. Had there been snowpack, the additional snowmelt could have led to even more significant flooding conditions.

Infiltration Rate

The infiltration rate from any rainfall is reduced as the ground cover becomes saturated, and when it reaches saturation, any additional rainfall will be entirely runoff. The Good Friday rainfall two days prior to the Great Flood had increased the topsoil moisture, but it is unclear whether the ground was saturated. The temperature of the ground can also affect the infiltration as the water moves faster at low viscosities. When the air and ground temperatures are cool like those days in late March, the viscosity is high and the infiltration decreases.

Rainfall Intensity

The next factor to consider is the rainfall intensity. A light steady rainfall might never exceed the infiltration rate and thus produce no flooding, even if rainfall totals exceed several inches over time. However, in this event, there was a period of intense rainfall at the onset and the infiltration rate was quickly overcome. The highest recorded rainfall rate was 1.05” in 28 minutes at Louisville, Kentucky on the 25th. It is likely that the ground reached its saturation point very early on given the time of year, recent rains two days prior, and high rainfall rates at the event onset. This would have resulted in very efficient runoff, and flashier or quicker floods.

Storm Size

The storm size altered with each storm system, and throughout the 3 to 4 days of rain, but the main axis of heaviest rain with 6 to 9 inches or greater covered an area from southern Illinois into northwestern Pennsylvania. This area represents approximately 50,000 square miles, affecting a population of approximately 5 million (based on the 1910 census).  The volume of water that fell in the Lake Erie and Ohio River watersheds during this event is approximated by the National Weather Service to be around 14 trillion gallons.  

Initial River Stages

All of the rivers and streams ultimately affected during the 1913 flood had initial stages were near normal and well below flood stage. This was another factor, like the lack of snowpack, that kept this event from being even more catastrophic.

Channel Capacity and Reservoirs

The rivers' channel capacity varied along every point of the many basins, but when this value is surpassed at a particular point, the flooding typically begins. In the Miami Basin, the Morgan Engineering Company took detailed measures to determine that, during the 1913 flood, the flows during the peaks of the flood were 500% and over 2500% higher than the river capacities in the Miami Basin. In Dayton, the flow of water through the city peaked at 250-275% the channel capacity at the time. This detailed study conducted in the Miami Basin post-flood was groundbreaking and provided much needed information for future of the Miami Basin flood mitigation.

Miami River Valley Channel Capacity vs. 1913 Flood
River	Location	Channel Capacity	Flood Discharge	Ratio of Drainage Capacity of Storm Flow	Ratio of Flow Exceedance	Drainage Area Square Miles
Mad river	West of Springfield	5.0	55.4	9.0	1108.0	488
Mad river	Below Osborn	6.5	75.7	8.6	1164.6	649
Mad river	Below Osborn	13.5	75.7	17.8	560.7	649
Stillwater River	Above Covington	1.2	33.1	3.6	2758.3	223
Stillwater River	Below Covington	6.0	51.4	11.7	856.7	448
Stillwater River	Above West Milton	7.0	86.2	8.1	1231.4	600
Loramie Creek	Northwest of Lockington	1.6	25.6	6.3	1600.0	208
Miami River	Above Sidney	5.0	34.1	14.7	682.0	498
Miami River	Below Sidney	5.0	48.5	10.3	970.0	575
Miami River	Below Piqua	10.0	70.0	14.3	700.0	842
Miami River	Tadmor	8.0	127.3	6.3	1591.3	1128
Miami River	Tadmor	12.0	127.3	9.4	1060.8	1128
Miami River	Below Dayton	25.0	252.0	9.9	1008.0	2598
Miami River	Below Miamisburg	35.0	257.0	13.6	734.3	2722
Miami River	Below Hamilton	25.0	352.0	7.1	1408.0	3672
Miami River	Below Miamitown	20.0	384.0	5.2	1920.0	3937
Twin Creek	West of Germantown	3.0	66.0	4.5	2200.0	272
Miami River	Sidney	10.0	44.0	22.7	440.0	555
Miami River	Piqua	25.0	70.0	35.7	280.0	842
Miami River	Piqua	15.0	70.0	21.4	466.7	842
Miami River	Troy	60.0	90.0	66.7	150.0	908
Miami River	Troy	20.0	90.0	22.2	450.0	908
Miami River	Troy	12.0	90.0	13.3	750.0	908
Miami River	Dayton	90.0	250.0	36.0	277.8	2525
Miami River	Dayton	100.0	252.0	39.7	252.0	2598
Miami River	Miamisburg	65.0	257.0	25.3	395.4	2722
Miami River	Franklin	65.0	267.0	24.3	410.8	2785
Miami River	Middletown	115.0	304.0	37.8	264.3	3162
Miami River	Hamilton	100.0	352.0	28.4	352.0	3672
Source:  Miami Conservancy District: Report of Chief Engineer Arthur E. Morgan Volume 1, Dayton Ohio March, 1916, page 25

Dams

In 1913, most dams were paid for by local communities for the purposes of flood control, water reservoirs, or recreation. The development of dams for electricity was in its infancy. After the flood of 1913, many local and state entities paid for an expansive network of flood control dams across the Ohio Valley. Later floods and the increase in electric generating dams led to a boom in dam construction, primarily in the 1930s-50s. These dams have reshaped several watersheds across the country. If the same storm were to move over the Ohio Valley today, the movement and channeling of water would be so redefined that it is unlikely that the impacts would be as severe as those witnessed 100 years ago.

Source: National Inventory of Dams Database

What would happen if the same storm occurred today?

Most of the communities that were affected in 1913 have since had a floodwall, dry dam, or other form of flood protection implemented in their watersheds. However, there is no doubt that the build up of cities and urbanization of the landscape today would allow for a faster and more efficient runoff. The hydrologists at the NWS River Forecast Centers, USGS, USACE, and research communities are working to improve river forecast models to be able to provide the most detailed and accurate forecasts available to the public in order to take action and protect as much life and property as possible. Using sophisticated river forecast models hydrologists have been able to simulate the river response today to a rain event similar to the 1913 flood for a few locations in the Ohio Valley. The resulting forecasts suggest some communities would see river levels higher than that of 1913,must likely caused by changes in ground cover and urbanization. For those communities that have increased their flood protection there was a notable reduction in the height of the river crest. For Dayton, Arthur Morgan’s goal of providing flood protection for a flood equal or up to 40% greater than that of the 1913 flood was validated through the model simulation.  The projected stage at Dayton’s river forecast point for a rain event similar to the 1913 storm would be around 40 feet. Though this stage is still greater than that of the January 22, 1959 flood, it is still below flood stage for the City of Dayton.  *This simulation cannot account for adjustments in reservoir releases, soil conditions, and rainfall rates during the 1913 storm which would undoubtedly alter the river stages. The value mentioned here is not to be used as a direct comparison with 1913 and was done for training and planning purposes only.

Great accomplishments have been made in the 100 years since the Great Flood of 1913, many of which were specifically driven by the outcry of citizens affected by the storm. Despite all the great improvements made to protect citizens from the threat of flooding, it is ultimately up to each individual to look out for the protection of their own lives and property when flooding is expected. Tools found on this website are available to help you and your family prepare. Also members of the Silver Jackets are available to help answer questions about flood risk and ways we can all work together to make us all safer.

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RECURRENCE INTERVALS

The following flood recurrence intervals data was collected from the most recent Flood Insurance Studies produced by FEMA for individual counties and communities. For more detailed information you can access your local FIS through the FEMA Map Service Center at https://msc.fema.gov.

Definition of a 100 Year Flood

Hydrologists don't like to hear a term like "100-year flood" because it is a misinterpretation of terminology that leads to a misconception of what a 100-year flood really is. A 100 year flood sounds like the kind of storm that if you experience in your lifetime than the likelihood of it happening again won’t be until your grandchildren are old. Instead of the term "100-year flood" a hydrologist would rather describe this extreme hydrologic event as a flood having a 100-year recurrence interval. In other words, a flood of that magnitude has a 1 percent chance of happening in any year.

Recurrence intervals and probabilities of occurrences
Recurrence interval, in years	Probability of occurrence in any given year	Percent chance of occurrence in any given year
100	1 in 100	1
50	1 in 50	2
25	1 in 25	4
10	1 in 10	10
5	1 in 5	20
2	1 in 2	50

 

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STREAM GAGING

Today, monitoring stream flow is a routine activity conducted by observers and automated gage networks across the country. The network of stream gaging stations serve a number of purposes from determining flow through a basin, decision support for reservoir releases, research, river flood modeling, and water quality monitoring.  Though stream gage readings had been taken for some time in Ohio, the first documented observation wasn’t until 1823 on the Sandusky River. Documentation of river flow and stage in the Ohio Valley becomes more widespread as the installation of canals, steam mills, flood walls, and reservoirs become more common.  Most of the stream gaging in Ohio before 1913 was done on an as-needed basis by local government agencies. The U.S. Weather Bureau recorded gage heights, but this record was good only for flood monitoring. The push for a more expansive statewide river gage network came about in the coming decades. For more information on The History of Stream Gaging in Ohio see the USGS report by Kimberly Shaffer.

  
Images: (Left) The Weather Bureau’s daily river stage sites. (Right) 2013 USGS, NWS, USACE, and local partnering agency river gage sites, the majority of which are automated and report observations several times a day. Source National Weather Service Cleveland