Note that the zero points (lengthwise) of most ditches is the center of the ditch along the east side of DE361. The zero points for the Bridge Rd south, Addy Rd north and Evergreen ditches are the west end of the respective culverts under Pine Rd; the zero point of the Addy Rd south ditch is its intersection with the Evergreen ditch (roughly 300' south of Addy Rd); the zero point of the Bridge Rd north ditch is the south end of the culvert under Bridge Rd. Data is from a 1992 Delaware Soil and Conservation survey (locating ditch heights and conduit locations), which was done relative to an arbitrary elevation. 2000 Artesian Water survey has elevations of all main culverts under roads-measured relative to Mean Lower Low Sea Level-the standard the USGS uses, and was used to convert the relative elevations to absolute. Tides at Jefferson Creek generally range between 0.5 and 1.5 feet above MLLSL; see this USGS site for specifics. |