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• • • • • • SECTION 2.0 • Background • • • The Koppel Stockton Terminal is a former dry fertilizer warehouse.A test grove of • 267 poplar trees was planted on approximately 1 acre at the southern end of the site in • May 1998 to evaluate the effectiveness of phytoremediation in removing nitrogen from soil and groundwater.An additional 1,250 hybrid poplar trees and 230 willow trees were • planted near the turnaround area,stormwater pond,former bagging plant,and in the area • north of the warehouse from March through June 2000.The original test grove,turnaround • area,stormwater pond,former bagging plant,and north of warehouse planting locations are presented on Figure 1-1. • Sampling of the monitoring wells and piezometers displayed on Figure 1-1 has been • performed since July 1996 to assess shallow and deep groundwater conditions and to • evaluate whether past site activities have affected local groundwater quality.Sampling data also help to establish trends in nitrate reduction due to phytoremediation at the site.Water • levels and groundwater quality have historically been monitored quarterly to assess local • seasonal variations. In May 2000,the Water Board granted approval to suspend analyses for • total Kjeldahl nitrogen(TKN) and total dissolved solids (TDS) for samples collected at the Koppel Stockton Terminal(Water Board,2000b).As of first quarter 2001,the frequency of • groundwater monitoring was reduced to semiannual. In September 2004,the Water Board • granted approval to reduce the frequency of monitoring to annual because data trends had been established for most wells onsite (Water Board,2004b).As required by MRP • No. R5-2004-0835,laboratory analyses conducted on groundwater samples are nitrate as • nitrogen and ammonia/ammonium. The Water Board approved suspending groundwater • quality monitoring for Monitoring Wells KP-7S,KP-7D,and KP-8S because of the low nitrogen levels that have been recorded at these wells (MRP No.R5-2004-0835;Water Board, • 2007). The depth to groundwater will continue to be monitored annually in these wells. • Field activities performed at the Koppel Stockton Terminal site from 2007 through 2011 • include the following: • • Routine maintenance activities such as maintenance of the irrigation system, tree • pruning,and collection and removal of leaves and undergrowth • • Annual groundwater sampling • • Annual tree surveys • Abandonment of monitoring well KP-11S in 2007 • In 2010,abandonment of four wells (KP-5S,KP-51),KP-10S,and KP-BG-1),installation of a replacement well for KP-10S(KP-10S-R), and installation of a paired deep well at KP-4 • (KP-4D) • • • • RDD1112370001(CAH5003.DOCX) 2-1 [�aersi�ws�mrmo • • •