elevation, the area is inundated during the growing season 

 on average at least biennially. 



(2) Comprehensive approach. Complete the following: 



(a) Decide whether hydrologic data reflect the apparent 

 hydrology. Data available from the gaging station 

 may or may not accurately reflect the area hydrology. 

 Answer the following questions: 



• Does the water level of the area appear to fluctu- 

 ate in a manner that differs from that of the water 

 body on which the gaging station is located? (In 

 ponded situations, the water level of the area is 

 usually higher than the water level at the gaging 

 station. ) 



• Are less than 10 years of daily readings available 

 for the gaging station? 



• Do other water sources that would not be reflected 

 by readings at the gaging station appear to signif- 

 icantly affect the area? For example, do major 

 tributaries enter the stream or tidal area between 

 the area and gaging station? 



If the answer to any of the above questions is YES, 

 the area hydrology cannot be determined from the 

 gaging station data. If the answer to all of the 

 above questions is NO, PROCEED TO (b) . 



(b) Analyze hydrologic data. Subject the hydrologic data 

 to appropriate analytical procedures. Either use 

 duration curves or a computer program developed by 

 WES (available from the Environmental Laboratory upon 

 request) for determining the mean sea level elevation 

 representing the upper limits of wetland hydrology. 

 In the latter case, when the site elevation is lower 

 than the mean sea level elevation representing a 

 5-percent duration of inundation and saturation dur- 

 ing the growing season, the area has a hydrologic 

 regime that may occur in wetlands. NOTE: Duration 

 curves do not reflect the period of soil saturation 

 following dewatering . 



When all of the above have been considered, PROCEED TO STEP 9. 

 • STEP 9 - Determine Whether Hydrology Is Adequately Characterized. 

 Examine the summarized data and determine whether the hydrology of the 

 project area is adequately characterized. For routine determinations, 

 there must be documented evidence of frequent inundation or soil sat- 

 uration during the growing season. For comprehensive determinations, 

 there must be documented quantitative evidence of frequent inundation 

 or soil saturation during the growing season, based on at least 



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