WORK PLANS - Laserfiche WebLink

Home Browse Search

0 41 3.0 Monitoring 3.1 Groundwater Monitoring Groundwater monitoring at the Koppel Stockton Terminal historically has consisted of quarterly sampling at four onsite monitoring wells and semi-annual sampling of three test grove piezometers.In June and July of 1999,eight additional monitoring wells were installed. Sampling of these new wells began in the second quarter of 1999. Constituents analyzed for include total dissolved solids (TDS),nitrate/nitrite-N,ammonia-N,and Total Kjeldahl Nitrogen(TKN) Field parameters measured include pH, dissolved oxygen(DO), and redox potential. To facilitate the monitoring of groundwater near the poplar groves,it is recommended that two new piezometers be installed at the locations shown on Figures 3 and 4. The first pie- zometer is proposed south of the Stormwater Pond area and the second piezometer is pro- posed along Hazleton Avenue,south of the former bagging area. A schematic diagram of the proposed piezometer construction is shown on Figure 7. Sampling of the proposed pie- zometers is discussed below. As discussed in the 1999 Annual Groundwater Monitoring Report (CH2M HILL,2000b)up to fourteen quarters of water quality data have been collected from monitoring wells at the Stockton Koppel Terminal.Trends established for historic wells generally show stable or decreasing constituent levels over time. The approach for groundwater monitoring for this remedial action is similar to that pro- posed in the 1999 Annual Groundwater Monitoring Report and is summarized in Table 2.It is recommended that historic wells KP-1R,KP-2,KP-3,and KP-4 be sampled annually;new wells KP-5S,KP-5D,and KP-6D be sampled quarterly through the year 2000 and semi- annually thereafter;offsite new wells KP-7S,KP-7D,KP-8S,KP-9S,and KP-BG1 be tested semi-annually starting with the second quarter sampling for 2000;and that test grove piezo- meters continue to be sampled semi-annually. The two piezometers installed as part of this remedial action would also be sampled semi-annually. This sampling schedule would pro- vide five to ten rounds of groundwater data for the 5-year review of this remedial action. Reporting is discussed in more detail in Section 4.The 5-year review will also include an evaluation of sampling frequency. Also proposed in the 1999 Annual Groundwater Monitoring Report is a revision to the list of sampling constituents.It is recommended that the constituent list be reduced to sampling for nitrate and ammonia only. Measurements for TDS can be inferred from the conductivity data collected during sampling and TKN would only be detected in those wells that have historically shown concentrations of ammonia. The TKN results have shown that most of the TKN is in the ammonia form and not the organic form of nitrogen. Therefore,it is pro- posed that TKN be removed from the constituent list. Lastly, the Monitoring Report recommends that groundwater measurements be reduced from quarterly to semi-annually to coincide with the groundwater monitoring. RDDI003676317.DOO(OAH716.DOO) 12