1. A Routine Wetland Delineation of previously classified Non-Hydric areas adjacent to IRD to determine the presence of hydric components and the implications of physical and environmental factors Da vid McCullough Department of Biological Sciences, York College of Pennsylvania Introduction/ Background  Wetlands impart flood water storage, filter water, and increase biological diversity. Farming is reduced to non- hydric areas. Indian Rock Dam (IRD) was built in 1939 to prevent flooding of surrounding areas; as the branches of The Codorus creek converge near IRD.  1987, The United States Army Corps. of Engineers compiled a comprehensive wetland delineation manual, which is the cornerstone of wetland delineations conducted in the U.S. 1988, data collection was completed in York Co [1,3, 4].  Wetlands are defined by three criteria: 1)Presence of hydric soils; soils inundated with water for periods of time to produce anaerobic conditions. 2)Hydrophytic vegetation; vegetation capable of being sustained in anaerobic environments. 3) Hydrologic evidence; physical evidence of periods of inundation [1,3, 4].  A previous wetland delineation defined a previously non-hydric (CM) area as satisfying the criteria of a wetland. These conditions are caused by the damming of WBCC when water levels exceed 8ft. at ZQ (gauging station just upstream of IRD). The retention of water can lead to severe inundations of surrounding areas. 1988, IRD gates were only lowered 7 days/yr. Minimal inundation was thought to occur from gate-closing; thereby, potentially reducing anaerobic conditions and qualifying the area for the CM assignment [4].  Assessments from adjacent areas were needed to determine the physical and environmental factors promoting the wetland conditions. Hypotheses/Objectives  To assess a CM area along TCC.  To use assessment as a comparative means and determination of variables promoting the conditions.  To propose a classifications more representative of the current conditions Method s Results 1. The project area was selected and defined 2. A base map was created (Fig. 1) 3. Total project area was determined (10.2 ha) 4. Nine transects were established 5. Gps was taken for each plot 6. Vegetation was identified 7. % cover was recorded for each species 8. Prevalence indices were calculated [1, 3, 4, 5, 6] 9. 132 soil samples were collected and Munsell characterizations were assigned 10. Evidence of hydrology was recorded 11. 24 years of gauge data was obtained and analyzed. Table 3 represents trends of specific interest. Fig 1. Base Map of area encompassing IRD and project areas Indicator IndexClass of vegetationProbability occurrence 1 1Obligate Wetland >99 2Facultative Wetland 66-99 3Facultative 34-66 4Facultative Upland 1-33 5Obligate Upland >1 Table 2. Represents mean percentage of hydrophytic species and prevalence indices for both sites [1, 3, 4, 5, 6] RegionPercent Hydrophytic Species 1 Prevalence Index WBCC 85.672.27 TCC92.312.16 Year880405060708 #1#1 710120431842 Table 3. Indicates select values representing the annual number of days where IRD gates were closed  Hydrophytic species dominated both sites Table (1, 2). Hydrophytic species were in greater abundance in the TCC site. Soil characterization differed substantially in both sites.  Table 3 provides a condensed summary of noteworthy annual IRD gate-closings.  TCC soil departed more substantially from the CM munsell notations.  Hydrology was apparent in WBCC and TCC sites.  Relatively high water table levels were observed in mid-winter Discussion  Both sites met and satisfied the wetland criteria. The data does not support the CM classification.  Topographical gradients and man-made drainage flows promote the present conditions.  Soils in adjacent higher elevations are excessively drained and promote the present conditions.  A combination of high converging water flow and relatively low banks exacerbate the conditions through the TCC site.  It would be more accurate to characterize the TCC site as CM with hydric inclusions.  Hydric BA, would be even more representative; the large degree of variation and water table levels correspond [4]. Literature Cited Acknowledgements 1.Environmental Laboratory 1987. “Corps of Engineers Wetland Delineation Manual,” Technical Report Y-87-1, US Army Engineer Waterways Experiment Station, Vicksnurg Miss. 2. Munsell Soil Color Charts. 1994. Revised Ed. Macbeth Division of Kollmorgan Instruments Corporation. 3. Porter Jr., R.B. 1988. National List of Plant Species That Occur In Wetlands: National Summary. For National Wetlands Inventory, U.S. Fish and Wildlife Service; Washington, DC, USA. Biological Report 88 (24-26.1). 4. USDA. 1993. Non-technical Soil Description Report. Soil Survey of York County, Pennsylvania. U.S. Department of Agriculture Soil Conservation Service. 5. Jongman, R.H., ter Braak C.J.F., and van Tongeren O.F.R. 1987. In Data Analysis in Community and Landscape Ecology. p. 83-86. Pudoc Wageningen, Weningen, The Netherlands. 6. Tiner, R.W. 2006. Lists of Potential Hydrophytes For The United States: A Regional Review And Their Use In Wetland Identification. Wetlands 26:2, 624-634. Dr. Bruce Smith, Ph. D; Thesis Mentor Steve Young; IRD personnel Donald Lambrechts; USACE personnel, guage data Mark MCDonald; Reagent’s Glen Dir. of grounds Table1. Represent Indicator indices and probability of occurrence. The index of 3 separates wetlands from uplands [1, 3, 5]. 1 Probability is represented as a percentage 1 Percentage of hydrophytes are represented as a percentage of the means for all transects Table 4. Defines letter notations for locations which are referenced. AbbreviationLocation IRDIndian Rock Dam CMCodorus silt loam soil BABaile silt loam soil ZQZinn’s quarry WBCCW. branch of the Codorus Creek TCCThe Codorus creek Figures 2a-d. Images represent hydrologic evidence and support the occurrence of inundations. 2a, b. Indicate the presence of inundations with ample force to wedge fallen trees against live trees 2c, 2d. Represent areas inundated with pooling water. 1 number of annual IRD gate-closings Figures 3a, 3b. Provide visual representations of the WBCC and TCC banks, respectively. 3a. WBCC banks 3b. TCC banks A B CD A B