Geotechnical Services- USACE



USACE, Philadelphia District

AEG was retained by the Philadelphia District of the USACE to perform four (4) reading sets annually of inclinometers and piezometers at seven dredged material disposal areas (DA) along the Delaware River, two (2) DAs at Wilmington Harbor, eight (8) DAs along the Chesapeake and Delaware (C&D) Canal. Additionally, data will be collected at three (3) small slide zones at the C&D Canal, and the C&D Canal Sludge Application Sites. There are a total of 21 inclinometers and 165 piezometers/monitoring wells at these sites that data will be collected during four collection periods throughout the year (one each quarter). The inclinometer readings shall use the current reading depths established for each inclinometer so that comparisons can be made to previous data sets. Check sums are performed in the field, and the calculated standard deviation shall be less than 25 in both the A and B directions in order to consider the data set valid. The piezometers and wells are open-tube type with outside diameters as small as 3/4". AEG used a water level indicator to read the piezometers to the nearest 0.01 foot. The time of the reading shall also be recorded in 24-hour clock time format to the nearest minute. After the data is collected, data processing occurred for each collected data set. For collected inclinometer data, the current reading set is compared to the initial reading set. Plots of "cumulative displacement vs. depth," "incremental displacement vs. depth," and “cumulative deviation vs. depth” for the current data set and at least four previous data sets were compared. For the piezometric and well data, compare the current readings to the previous readings, and flag readings that change more than 5 feet (up or down). After the data was processed initial data interpretation was completed by explaining any piezometric data flagged during data entry. For data entry errors in collection and/or transfer and evaluate flagged data versus previous readings, construction or operational activities at the site, and recent precipitation If inclinometer readings indicate a distinct plane of movement not indicated in the previous reading set AEG would notify the USACE within one working day of this discovery to discuss potential issues. All data/information is compiled into a report submitted to the USACE on a quarterly basis.