FAQ - Ohio Water Science Center

How do I get a record of gage heights and other unit data older than 31 days?

Currently, the only way to gage-height and unit water-quality data is by special request. Use this link to send a message to our information team, and be sure to specify exactly what kind of data and what period of time you’re interested in.

Instantaneous unit streamflow data can be obtained from the Instantaneous Data Archive, or IDA. This repository contains only unit streamflow data and only data that have been approved as final.

What do the flags and remarks mean in your tab-separated unit-data retrievals?

Click here to get an explanatory list of these symbols.

Can I obtain a stage-discharge rating for a particular streamgage site?

You can obtain a shift-adjusted rating table by if streamflow (discharge) is currently being computed at the site by entering a  URL of the following form in your browser’s address bar:

http://waterdata.usgs.gov/nwisweb/data/exsa_rat/XXXXXXXX.rdb
where XXXXXXX should be replaced by the site number.

If the streamgage is a stage-only site, no valid or current rating exists.

How do I find the location of a USGS streamgage in Ohio?

Go to the Real-Time Water Data area of  NWISWeb and use the map or the Statewide Streamflow Table to bring up the site record. If the narrative description on the real-time page is insufficient for your purposes, you can see a mapped view by selecting “Site Map” from the pick list under “Available data for this site.”

Why has streamflow been discontinued at some streamgages but gage heights (stages) are still reported?

Computation of streamflow is an expensive part of operating a streamgage because of the amount of fieldwork, record editing, and record review involved. If funding for a particular streamflow site cannot be maintained at a sufficient level, we sometimes need to downgrade a station to stage only. For some stations, gage height is the issue of interest, not streamflow, so those streamgages may be established as stage only from the outset.

How do I find flood stage for a particular place on an Ohio stream?

Flood levels are designated by the National Weather Service for their forecast sites and consequently are not defined for all of the stream gages that the USGS operates. If you are interested in flood and high-flow information, try this link.

You can quickly determine where streamflows in Ohio are high and water levels are above flood stage. If you use the mouse to move the pointer over one of the gage symbols, a small box is displayed which includes useful information including the station name and number, current gage height (stage), and flood stage (where defined). Flood stages are shown even when current stages and streamflows are low. Detailed information on floods and flood forecasts also can be obtained from the National Weather Service’s Advanced Hydrologic Prediction Service in Cleveland and Ohio River Forecast Center in Wilmington.

What are gage datums, and why do they have different references among the Ohio stations?

Gage datum is a horizontal surface used as a zero point for measurement of stage or gage height. This surface usually is located slightly below the lowest point of the stream bottom such that the gage height is usually slightly greater than the maximum depth of water. Because the gage datum is not an actual physical object, the datum is usually defined by specifying the elevations of permanent reference marks such as bridge abutments and survey monuments, and the gage is set to agree with the reference marks. Gage datum is a local datum that is maintained independently of any national geodetic datum. However, if the elevation of the gage datum relative to the national datum (North American Vertical Datum of 1988 or National Geodetic Vertical Datum of 1912 or 1929) has been determined, then the gage readings can be converted to elevations above the national datum by adding the elevation of the gage datum to the gage reading.

How do I find . . .

-the magnitude and frequency of a particular flood?

-low-flow and other types of flow statistics?

-drainage area for a particular place on a stream?

You can find answers to all these questions by use of the StreamStats application for Ohio. Published USGS reports are also available: flood magnitude and frequency (and description of StreamStats), various streamflow statistics, low-flow and flow-duration statistics. Drainage-area information can also be found in the Ohio Department of Natural Resources, Division of Water’s Gazetteer of Ohio streams.

How do I find the highest measured water level (gage height, or stage) at a particular Ohio streamgage site?

Go to the NWISWeb surface-water area for Ohio and select “Peak-flow Data” from the menu options. The “Table” output format will list gage heights as well as measured annual peak flows.

How do I get flood maps or 100-year flood heights for my neighborhood?

The FEMA Map Service Center is the principal source of these kinds of maps. You can even generate a customized map of your area (a Firmette) online. Additional information, including names of local flood administrators, can be obtained by the Ohio Department of  Natural Resources, Division of Water, Floodplain Management Program.

How often do your real-time stations update? Some seem to take several hours even though the data are reported for much shorter intervals.

Data are transmitted from gage locations every 1 to 4 hours during normal operation, depending on the type of equipment at the station and the availability of communications-satellite channels for relay. As technology advances, we hope to reduce these delays. If a station hasn’t reported for a day or more, chances are that something is wrong somewhere in the chain of data transmission. Feel free to inform us of any apparent outages by emailing us.

How do I get gage-height and flow information specifically for the Ohio River?

Gage-height data more than 31 days old (no longer showing on NWISWeb) can be requested from the USGS Kentucky Water Science Center or the West Virginia Water Science Center for Ohio River streamgages bordering their respective states; click on “Questions about sites/data” at the bottom of the NWISWeb pages to make an email request. The U.S.Army Corps of Engineers (USACE) also collects information at some other locations that don't appear on our web page (for example, see here). Because the Ohio River is such a highly regulated stream, flow information is very sparse; however, the USACE is generally the best source.

How/where can I get USGS publications, including those that the Ohio Water Science Center has produced?

The vast majority of USGS publications, including the Ohio WSC’s, are available from the USGS Publications Warehouse. Printed copies of many Ohio WSC publications are available at no cost and can be requested by email.

How/where can I get hardcopy and digital topographic maps?

For Ohio, hardcopy maps can be ordered from the Ohio Department of Natural Resources, Division of Geological Survey. They can also be ordered directly from the USGS; digital versions are available for free download from the same Web address.

How/where can I get hydrologic GIS datasets?

For Ohio, detailed watershed boundaries can be obtained from the Ohio Natural Resources Conservation Service (NRCS) web site. For watershed boundaries bordering Ohio, there are a couple of good sources of data: The NRCS Watershed Boundary Dataset site has links to other sites and individual states are also good sources of data: Michigan, Indiana, and Pennsylvania.

Alternatively you can create your own watersheds using the USGS StreamStats Tool.

Hydrologic networks (GIS jargon for rivers, streams, and creeks) can be obtained in multiple levels of detail (down to 1:24,000 scale) from the USGS National Hydrography Dataset (NHD).

How/where can I get aerial/satellite photos of Ohio and other places?

USGS aerial images can be located by way of the USGS Store. The Ohio Department of Transportation also has an extensive set of aerial images for Ohio. Several non-governmental sources now make aerial imagery available to view or order online, among which are Google Maps, Google Earth, and Terraserver.

Where can I get current data for lakes and reservoirs and find out about reservoir releases?

The U.S. Army Corps of Engineers operates most of the reservoirs in Ohio and is usually the place to go for this kind of information. The Corps’ Huntington District operates reservoirs in eastern and central Ohio, and the Louisville District operates a few reservoirs in southwest Ohio. For fishing and boating purposes, the organization “Go Fish Ohio” has downloadable maps for selected lakes. The USGS does have real-time gage-height information for a few lakes and reservoirs in Ohio.

Can I request to have a temperature reported for a streamgage site where temperature isn’t measured now?

Adding and maintaining temperature equipment to a stage-only or streamflow station costs extra money, so we need outside support to fund this addition above and beyond the funding for stage or flow. If you would like to see temperature readings at a favorite fishing or boating site on an Ohio stream, contact us. We’ll explain how you might be able to work with a tax-supported entity to help fund the upgrade.

What’s a good and safe streamflow for fishing at a particular site?

A given streamflow (for example, 215 cubic feet per second (cfs)) means different things at different sites. On a river that drains a large area, 215 cfs may be a trickle. On a small stream, it may be a flood. If you are trying to figure out when the river is wadeable, you might look at our measurement page for the gaged site of interest. You will see the gage heights corresponding to wading measurements we have made (as indicated in the “meas. type column”). Obviously, at a given gage height, it may be possible to safely wade in some locations and not in others so be careful, wear a personal flotation device, and take other precautions.

As for what’s a good flow for when the fish bite, we’re too busy tending to our gages to have time to find out! However, there are many other places to check. Following are just a few we know of (Note: mention of web sites does not constitute an endorsement by me or the USGS):

Ohio Dept. of Natural Resources, Division of Fish and Wildlife

Go Fish Ohio

Ohio Central Basin Steelheaders

Great Lakes Council of the Federation of Fly Fishers

What’s a good and safe streamflow for kayaking or canoeing at a particular site?

The American Whitewater organization has a database that relates USGS real-time data to their judgment of whether the stream is "running" too low or too high for paddling.

Where do I find information on USGS bench marks? For instance, if I need to get an elevation or want to report a bench mark that's been destroyed or that needs to be moved?

Following  is the contact information:

U.S. Geological Survey

Science Information and Library Services

1400 Independence Road, Mail Stop 231

Rolla, MO 65401

Toll Free:  888-ASK-USGS, choose option #2

Phone: (573) 308-3500

Fax: (573) 308-3615

Email: mcmcesic@usgs.gov

How do I get my well tested for water quality?

Many local health districts in Ohio offer some kind of testing. A directory of these districts can be found at the following Ohio Department of Health Web site.

How deep is ground water in my area?

This is a difficult question to answer because ground-water conditions can differ dramatically over short distances. Also, there are many places in Ohio where shallow ground water is underlain by deeper aquifers that yield greater amounts of water with less susceptibility to drought. The Ohio Department of Natural Resources, Division of Water’s online potentiometric (water-level) surface maps and ground-water resource maps can give you a general idea of ground-water depth and yield in your county. The Division’s well-log search tool can show the characteristics of water wells drilled in your township or on your road.