Ohio Wetlands

Regional History.

The state of Ohio has a wetlands history similar to national trends. In the past 200 years over 90% of Ohio’s wetlands have been destroyed as a result of human impacts (GLC 2002). The Great Lakes Basin watershed once was dominated by a variety of wetland ecosystems. 150 years ago in northwest Ohio, the Great Black Swamp covered 1500 square miles and the Lake Erie Marsh stretched from Sandusky Bay to Maumee Bay (Gordon 1969). This significant wetland dominated watershed is now a patched network of shrinking landscapes.

On the geologic time scale NW Ohio was once a vast sea. During the last glacial maximum the Wisconsin glacier formed many distinctive features regionally. The glacier lakes are considered to be instrumental for the creation of three main features; the Great Black Swamp, Oak Openings, and the Lake Erie and Sandusky Bay marshes (Lafferty). Today Oak Openings is a unique system all land uses. Oak Openings is in fact a broad ridge of fine yellow quartz sand that extends from Liberty Center northeast towards Detroit. It covers parts of Henry, Fulton, and Lucas counties. The sand based soil lies upon clay type soils creating a matrix of ecosystem networks. The sand came from Michigan over thousands of years. Ancient glacial lake wave currents carried sand along the edges as lateral moraines. The Lakes dropped and wind began to slope sand dunes. These dunes have up to 35 feet in topography and can be from 3.5 to 7 miles in width with depth 15 – 50 feet. The drainage very poor and water lies within three feet of the surface in many areas. These rare combinations created many of the wetlands in the region.

Irwin Prairie, Lucas County Ohio, Late Fall 2003.
The ‘Great Black Swamp’ was once dominated NW Ohio. This tract nearly equaled the size of Connecticut being 120 miles in length by 40 miles in width. It contained a diverse plant community including birch, ash, elm, oak, cottonwood, poplar with maples, basswood, hickories shagbark, and shellbark (Gordon 1969). The population of Ohio grew rapidly which caused major alterations of the land uses. NW Ohio populations nearly doubled ever 10 years during the latter half of the 19th century (OHS 1997). During the 1860s in Ohio the railways used 1 million cords of wood annually for fuel alone. Intense logging between 1860 –1885 occurred in the Black Swamp region of NW Ohio to supply the growing demand of rich agricultural lands, industry, and transportation (Lafferty).

Ditches across the landscape began to drain the natural wet meadows and prairies (Gordon 1969, Jaeger 2001). One natural meadow was six miles long, and 2 miles wide adjoined the town of Circleville. During the 1820s ditches started to eradicate prairies for farmland purposes. Hardin County alone contained 25,000 acres of marshlands before the mass growth of Ohio. Within Lucas County, vast areas along the lakeshore began to be diked and pumped to take advantage of the rich farmland (Jaeger 2001). By the mid 1900s Lucas County had been largely reclaimed for agricultural purposes. It is estimated that small ditches dug over several years totals hundreds of miles (Bednarik 1984). The Lake Erie Marsh once extended from Sandusky Bay and Cedar point to the Maumee Bay and nearly 20 miles inland from its current shoreline.

Today the installation of new ditches is less common and the greatest threat to wetlands is from filling and groundwater lowering. Filling all or a portion of a wetland is a growing problem as development pressures increase the competition for available land. Properties that historically would not have been built upon because they were too low or too wet are now being filled at an alarming rate. The result is a complete loss of all the natural functions of that wetland.

A less obvious, but just as serious, threat to Northwest Ohio wetlands is lowering of the groundwater table. Many wetlands are dependent upon groundwater for their survival. This water originates from rainfall that sinks into the ground and eventually saturates the rock and/or soil. In some areas the groundwater is significant enough that it completely saturates the ground and is visible above the surface. The survival of many wetland plants and animals is intimately tied to these areas of high groundwater. Basement sump pumps, wells and groundwater pumping, related to mining activities, all lower groundwater levels if the demand exceeds the supply. Increasing development activity near wetland areas is negatively effecting the groundwater in many local wetlands (Siedel 2002).
Taking GPS, location information for wetland delination for ground truthing. Late fall Lucas County, Oh
Ohio Wetlands Regulations.
The U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency define wetlands as those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands exhibit an incredible array of ecological benefits including holding storm water, allowing gradual recharge of groundwater, providing critical habitat for plants, fish and wildlife, controlling erosion, mitigating water pollution, providing food and recreational bases for people, and contributing to a healthy water cycle and lake levels (Tiner 1999).

The Ohio Wetland Inventory shows areas of shallow marsh (emergent vegetation in water three feet or less), scrub shrub wetland (emergent woody vegetation three feet or less), forested wetland (mature woods with hydric soils), wet meadow (wet grass areas in water less than six inches on hydric soils) and farmed wetland (wet meadow in agriculture areas on hydric soils). The Ohio Wetlands Inventory is based on analysis of satellite data and is intended solely as an indicator of wetland sites for which field review should be conducted (Yi et al. 1994). The satellite data reflect conditions during the specific year and season the data was acquired, therefore all wetlands present in an area may not be indicated. Statistics generated from the inventory are intended solely as an approximation.

The wetlands inventory for the State of Ohio was produced by the digital image processing of Landsat Thematic Mapper Data. The Thematic Mapper is a multi-spectral scanner that collects electromagnetic radiation reflected from the earth's surface in the visible, near infrared and mid infrared wavelength bands. The resolution of the Thematic Mapper data is a 30 meter by 30 meter cell (Schaal 1995). The USGS and National Wetland Inventory (NWI) groups traditionally use seasonal aerial photography to depict wetlands. The most recent classifications performed regionally were over a decade ago. Recently as of 2004, a mixture of groups and parties are investigating updating wetlands maps for the state of Ohio.



References.
Bednarik, K.E. 1984. Saga of Lake Erie marshes in Hawkins et al. Pioneering waterfowl management in North America. US Fish and Wildlife Service. Washington DC.

Gordon, R. 1969. Ohio Biological Survey. The natural vegetation of Ohio in pioneer days. V.3. N.2. Ohio State University.

Great Lakes Commission (GLC). 2002. An Overview of US Great Lakes Areas of Concern. Great Lakes National Program. US Environmental Protection Agency Report.

Jaeger, J. 2001. Wetlands History in Northwest Ohio and Lucas County. Metropark District of the Toledo Area Bulletin.

Lafferty, M. Ohio’s Natural Heritage. The Ohio Academy of Science. Columbus, Ohio.

Ohio Historical Society & The Ohio Public Library Information Network. 1997. [On-line]. Available:
http://www.oplin.lib.oh.us.

Schaal, G. 1995. Methods used in the Ohio Wetland Inventory. Columbus, Ohio: Ohio Department of Natural Resources.

Siedel, T. 2002. Wetlands Bulletin.

Tiner, R. 1999. Wetland Indicators. A Guide to Wetland Identification, Delineation, Classification, and Mapping. New York: Lewis Publishers.

Yi, G.D., Risley, M., Koneff, M., and Davis, C. 1994. Development of Ohio’s GIS-based wetlands inventory. Journal of Soil and Water Conservation 49:23-28.

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