W A T E R S H E D F A C T S Total watershed area 140 mi 2 Average annual rainfall 38 in Average annual temperature 58 F Elevation Max 1321 ft Min 899 ft C. J. Brown Reservoir controls flow from 83 mi 2 of the Buck Creek watershed 53 combined sewer overflows contribute flow to Buck Creek during runoff events Tributary of the Mad River which drains into the Great Miami and Ohio Rivers Located in Clark and Champaign Counties, Ohio Population Springfield 62,400 County 144,700 L A N D U S E A N D C O V E R Agriculture 70 % Open Space 11 % Urban 9 % Forest 8 % Other 2 % Municipal Stadium Wetland Municipal Stadium Wetland is a riverine wetland adjacent Buck Creek just downstream from the recreational structure near Municipal Stadium (Fig. 1). In a recent Looking Back article (7/16/2012), Springfield News-Sun reporter Tom Stafford determined that the presence of this wetland is the result of a break in the levee on the east side of Buck Creek during the 1937 flood. According to the 1937 Springfield Conservancy District report, Buck Creek peaked at a stage of 8.6 ft with a discharge of 8,000 cfs. (Stage, discharge, and other technical terms used in this fact sheet are defined in a glossary at the end.) This break was apparently not repaired or, if it was, it was breached again by later, larger floods, including the flood of record for Buck Creek, the 1959 flood. Today the wetland functions for the benefit of Buck Creek water quality and the local ecosystem. The objectives of this fact sheet are to describe defining properties of a wetland and that characterize Municipal Stadium wetland, define the natural function of this wetland and how it benefits Buck Creek and Springfield, and describe current and future activities that will increase the function of this wetland as well as provide educational opportunities for the Springfield community. Wetland Characteristics According to the U.S. Army Corps of Engineers, a wetland is defined as those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, Fact Sheet 5 Accidental Advantage of an Urban Wetland a prevalence of vegetation typically adapted for life in saturated soil conditions. It follows that wetlands are identified on the basis of three factors; hydrology, hydric soils, and hydrophytic vegetation. (Refer to the glossary for definitions.) Wetland hydrology is the most influential factor in the formation of a wetland because water and saturated conditions are critical to the formation of hydric soils and the presence of hydrophytic vegetation. A wetland is inundated either permanently or periodically at mean water depths <6.6 ft, or the soil is saturated within 12 Figure 1. The Municipal Stadium wetland is accessed from the bike trails. The wetland is flooded at A and/or B, depending on the stage of Buck Creek, as shown in Fig. 2.
groundwater is present in lower elevations of the wetland year-round. Figure 2. The Municipal Stadium wetland is flooded from the upstream direction (A) during high flow events and from the downstream direction (B)during intermediate flood events. The location of A and B are illustrated in Fig. 1. in of the surface for consecutive days for more than 12.5% of the growing season. With a growing season of approximately 165 days, this would amount to 21 days. Sources of water for the Municipal Stadium wetland include direct precipitation, overflow from Buck Creek (Fig. 2), or subsurface groundwater flow. During low flow conditions on Buck Creek, groundwater flow drains to the south and exits the wetland at B in Fig. 1. Wetlands are also delineated on the basis of hydric soils. Hydric soils form in anaerobic, or reducing, environments that result under saturated conditions. Anaerobic soils are depleted with respect to oxygen because available oxygen is consumed during decay of organic material deposited in the wetland. Wetland soils can be divided into two subcategories of hydric soils; organic soils, or histosols, and mineral soils. Histosols, often referred to as peats or mucks, are dark in color, occur in the upper soil, and are composed of more than 50% organic matter. Mineral soils are comprised mostly of sand, silt, and clay and generally occur beneath the organic layer in a wetland. These soils vary in texture and color. Colors range from red to gray, depending on whether the soil environment is oxidizing or reducing. In a wetland, mineral soils are saturated long enough that they are able to undergo chemical and physical changes that reflect a reducing environment. Soils in the Municipal Stadium wetland are rich in organics but are interspersed with layers of mineral soils as a result of periodic flooding. They also have a rotten-egg smell that is typical of a reducing environment. Hydrophytic vegetation, aquatic plants that are adapted to saturated soil conditions and prolonged inundation in the wetland environment. These plants are able to reproduce and thrive in the anaerobic conditions that characterize hydric soils. The Municipal Stadium lacks one of the plants most expect to see in a wetland, Overflow from Buck Creek is especially dominant during stormflow and higher baseflow stages. Relative to the Plum Street Gage (http://v4.wqdata.com/ webdblink/buckcreek.php), streamflow from Buck Creek backflows into the wetland at B (Fig. 1) when the stage of Buck Creek is greater than 5.03 ft (Fig. 2). For significant floods, with stages greater than 7.18 ft, Buck Creek overflows its banks at several points, including at A, and exits the wetland at B in Fig 1 as flood flow recedes. The duration of time the wetland is flooded depends in part on the time Buck Creek is at a stage of 5.03 or greater, generally ranging from hours to weeks, but a b Figure 3. Wetlands are delineated on the basis of hydrology, soils, and vegetation. Common arrow-head (Sagittaria latifolia) (a) and yellow flag iris (Iris pseudacorus) are obligate wetland species, meaning they require the wet conditions associated with wetlands to thrive. Both are invasive species, considered noxious weeds in some states.
cattails. Two plant that are in abundance and, like cattails, grow only in saturated or inundated conditions are common arrow-head and yellow flag iris (Fig. 3). During summer and fall, when water flow in the wetland is dominated by groundwater, duckweed is also present. Duckweed, or water lentils, is an aquatic plant that floats on or just beneath the surface of still or slow-moving water. Duckweed tends to be associated with fertile conditions. It is an important high-protein food source for waterfowl and, when covering the water surface, reduces evaporation from the wetland. referred to as dynamic surface water storage if it is retained for a timespan of hours to days and long-term surface water storage if it is retained for timespans of days to weeks. This is illustrated in Fig. 4. Following two separate stormflow events for which peak stages exceeded 5.03 ft, wetland stage increased for both events in step fashion by approximately 0.5 ft for each.storm. The rise in wetland stage for each event was fast, rising over the course of several hours, but the fall was less steep, dropping less than 0.1 ft over 2-3 days. This indicates the water was being stored in the wetland. Retaining flood water in the wetland, even for a short period of time, can influence the timing and severity of flooding downstream. The longer water is retained, the greater its potential for recharging groundwater. This in turn is discharged to Buck Creek, sustaining baseflow during dry months. Wetland stage increases in the winter and spring seasons in response to increased stormflow coupled with less evaporation during the cooler months. It decreases in the FUNCTION OF A WETLAND Wetlands are valued because of the services, or functions, they provide. Can the Municipal Stadium wetland, which formed as a result of an accidental breach of the levee along Buck Creek, provide valuable services? Wetland functions are defined as a process or series of processes that take place within a wetland. These include hydrologic functions, like the storage of water, biogeochemical functions, like the transformation of nutrients, and habitat functions. Riverine wetlands, like the Municipal Stadium wetland, function as sinks or reservoirs for excess water, sediment, and nutrients in floodwater. Two wetland functions will be illustrated using data from the : surface water storage and removal or retention of sediment. The Municipal Stadium wetland begins to flood when the stage of Buck Creek exceeds 5.03 ft. When the stage of stormflow recedes below 5.03 ft, some of the water in the wetland drains back into Buck Creek, but some is retained by the wetland. This function is Figure 4. Stormflow from Buck Creek floods the Municipal Stadium, raising wetland stage. Wetland stage does not rise and fall in sync with Buck Creek indicating that it is storing floodwater, releasing it slowly over time and providing recharge to groundwater.
dryer summer and fall seasons as the water table falls and groundwater discharges to Buck Creek. Stormflow is generally charged with sediment, the dominant source of pollution in Ohio watersheds that are dominated by agriculture. A second important function the Municipal Stadium wetland performs is for removal of imported elements, including nutrients, and particulate matter like sediment. An example from the Buck Creek Educational Corridor using turbidity illustrates this function (Fig. 5). Turbidity is a measure of water clarity which is affected by suspended sediment or sediment that is transported within the water column. Fig. 5 illustrates a stormflow event that occurred on Buck Creek. It exceeded a stage of 7.18 ft and flooded the wetland thereby increasing wetland stage. Water quality probes placed in Buck Creek just upstream from the wetland (i.e., the Upstream station on the monitoring network) and within the wetland measured turbidity for this event. Wetland turbidity was greater than Buck Creek turbidity, as illustrated at A in Fig. 5, and turbidity in the wetland was greater than in Buck Creek following peak stormflow, as illustrated at B. The inset image shows the turbid nature of the water. As the result of another wetland function, energy dissipation, the velocity of water flowing into riparian wetlands is generally less than in the flooded stream. This is true in the Municipal Stadium wetland. The fine sand fraction is suspended in Buck Creek flood flow, but as that water enters the wetland and slows down, sand quickly settles out. The turbidity of stormflow in the wetland is dominated by silts and clays that take longer to settle out of the water column. That turbidity in the wetland is greater than in Buck Creek (A in Fig. 5) suggests that silts and clays are accumulating in the water column due to the slower velocity of flow. As stormflow stage and turbidity decrease on Buck Creek, turbidity in the wetland initially decreases, perhaps as the silt fraction settles out, then remains elevated (B in Fig. 5). By removing sediment from stormflow in the wetland, downstream sediment pollution is decreased. In addition, nutrients such as phosphate which is adsorbed onto and transported with particulate matter, is also retained. FUTURE OF THE MUNICIPAL STADIUM WETLAND As part of the, we have recently installed a rain gage, a wetland stage gage, and a water quality sonde in the Municipal Stadium wetland. Wetland stage and physical water quality parameters, including temperature, dissolved oxygen, specific conductivity, odixation-reduction potential, ph, and turbidity, are being logged at 15-min intervals. The data are not available on-line but will be sent to those interested in using it in their classroom or for science research projects. Contact information is provided at the end of this fact sheet. In addition, in the near future, invasive plant species will be removed from an area in and adjacent to the wetland. Invasive plants, including honeysuckle, will be removed as part of a stream mitigation strategy to offset stream disturbances associated with a local highway project. The result will be a wetland environment with clearer lines of sight and greater sun penetration, both of which should benefit the wetland itself as well as increase safety of those using the wetland for education. Figure 5. Turbid stormflow from Buck Creek is charged with sediment eroded from banks and upland areas. As water stage in the wetland recedes following flooding, sediment in the water column is stored within the wetland. The phenomena marked A and B are described in this fact
Glossary (after Brinson et. al., 1995 & USACE Wetland Delineation Manuel, 1987) Baseflow the stage or discharge condition of a stream where streamflow is dominated by groundwater discharging to the stream. It tends to be higher in the winter and spring and lower in summer and fall. Discharge the volume of water moving past a cross section of the stream during a given period of time; a typical unit of discharge is cubic feet per second or cfs. Dynamic Surface Water Storage a hydrologic function of a wetland that describes its ability to store moving surface water for a short period of time following overbank flow or flooding. Function process or series of processes that take place within a wetland providing its value (e.g., wetlands may function as habitat for amphibians). Histosols hydric soils that consists of > 50% organic material in the upper 32 inches; also referred to as a peat or muck. Hydric Soils saturated or inundated soils within a wetland with properties that characterize saturation (e.g., rotten egg smell from reduced, anaerobic conditions). Hydrograph record of change in water depth or discharge over time. Hydrology the study of the physical and chemical processes of water and how they influence the areas surrounding; a key factor for identifying a wetland. Hydrophytic Vegetation aquatic plants that have adapted to be successful in the saturated soil conditions and prolonged inundation found in a wetland. Inundation submersion of an area with water, typically associated with flooding. Long-term Surface Water Storage a hydrologic function of a wetland that describes its ability to retain water for long periods of time. Mineral Soils soils that consist predominantly of mineral matter in clay, silt, and sand sizes and are the result of chemical and physical weathering processes. Nitrate a form of nitrogen that is essential for plant life, occurring naturally in soils or applied as in the form of fertilizer. Overbank Flow flooding that occurs when streams overflow their banks and inundate the floodplain and riverine wetlands on the floodplain. Retention the ability of a wetland to store water without significant loss over a period of time. Riverine Wetland located on floodplains next to rivers, the source of water is the river in flood or high water table adjacent the river. Riverine Wetland located on floodplains next to rivers, the source of water is the river in flood or high water table adjacent the river. Stage the relative depth of measured against an arbitrary datum or level; a typical unit of depth is feet or ft. Stormflow the stage or discharge condition of a stream where streamflow is dominated by storm runoff. Flooding occurs as a result of stormflow. Turbidity a measure of water clarity; sediment load in turbid water reduces water clarity. Objectives of the Need Additional Information? John B. Ritter Department of Geology Wittenberg University P.O. Box 720 Springfield, OH 45501 Phone: 937-327-7332 Fax: 937-327-6489 E-mail: jritter@wittenberg.edu assess the environmental impact of in-stream and watershed changes on water quality over time; provide problem-based learning opportunities related to stream environments for area K-16 students; and provide current weather and water information to recreationists taking advantage of recreational amenities along the creek corridor. The Web-Interface for Real-Time Data is hosted by NEXSENS Technology, Inc.