2009-323A - Laserfiche WebLink

Home Browse Search

prediction and interpretation of basin performance and effluent quality in terms of these standards can be problematic . This situation arises from the incompatibility of established design and compliance criteria. State standards for effluent turbidity are expressed in terms of optical clarity relative to ambient conditions of the receiving waters . By comparison, containment area design guidelines published by the U .S . Army Corps of Engineers Waterways Experiment Station (WES) under the Dredged Material Research Program (DMRP) relate containment area performance to the suspended solids concentration of the effluent . The level of turbidity produced by a specific suspended solids concentration depends highly on the physical characteristics of the suspended material . Previous investigation (e .g. , Walski and Schroeder, 1978) could not establish a method to effectively translate suspended solids concentration to optical clarity even for sediments with well-defined physical characteristics. The design and operation of this and other similar sites would greatly benefit from such a predictive relationship . A primary objective of the effluent monitoring program should be to relate suspended solids concentration to the state performance criterion based on turbidity for sediments typically encountered in the ICW W . 3 . 5 Groundwater Monitoring As discussed in Section 2 .4, groundwater monitoring forms a key element of Site IR- 14 ' s long-term management. Sampling and analysis of groundwater throughout the dredging and decanting operation comprises an essential component of the monitoring program . The duration of this program component should extend from the start of dredging to the completion of decanting, a period projected to last about 8 to 12 weeks. The site ' s first use as a containment facility will likely be the most crucial period for monitoring the potential seepage of saline water through the dike ' s side slopes and foundation . During this time, soils forming the dike will be most porous due to their disturbance during site construction. Thus, the initial period of each dredging operation requires frequent sampling and analysis of groundwater. During the site's initial use, groundwater samples should be taken twice every 24 hours . This sampling regimen should begin at the start of dredging and continue for a period equivalent to the theoretical transit time of saline water from the basin to the furthermost sampling well . Maximum transit time should be estimated during the final site design process, given adequate datato define soil permeability, stratification, and the governing groundwater flow gradient . Such data should be obtained from core borings taken in association with monitoring well 34