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measurements (Group B). Figure D-98, Eastwood Ests. is a good example of this type of <br />behavior. <br />In an effort to obtain the highest quality autumn water level data, autumn water levels and their <br />respective wells were evaluated for likelihood of being impacted by local pumping. Wells that <br />have a low likelihood of being impacted by local pumping should comprise a subset of fl1e <br />autunul measurements of higher quality data that can be used to evaluate seasonal variability in <br />aquifer water levels. Water level measurements from other wells that show the effects of <br />pumping are still valuable both for long-term trends and for depicting localized pumping <br />impacts, but are less beneficial for understanding seasonal trends on a more regional basis. <br />Several criteria were established to select the wells with higher quality data that have been <br />physically measured through the Task 39 field program. Solicited wells were excluded from <br />this list due to the lack of information regarding the pumping status of the solicited wells. The <br />first criterion was to eliminate domestic wells and lalown active public supply wells, because <br />these wells are more likely to Have been pumping shortly before or during the water level <br />measurements, w11ic11 would have affected local water levels in ways t11at could not be <br />quantified. Of t11e remaining wells, those without pumps and those that are believed to not <br />pump in the autunul were selected. Other wells where pumping status was less certain <br />comprised a secondary class and included wells with a pump installed that an owner claims to <br />have not used in years. The hydrographs of these latter wells were evaluated and those that <br />showed a predictable seasonal variation were selected, while those which showed more random <br />data indicative of potential pump>11g (or nearby pumping) were not selected. Of fl1e 65 <br />bedrock wells measured by CDM in phase 4 (Table 1), there are 13 wells considered to show <br />higher quality data whose seasonal measurements are not affected by pumping. Additionally, <br />all five alluvial wells measured by CDM in the designated basins were selected since all are for <br />agricultural use and are likely not pumping in the late autumn or winter. The resulting 18 <br />wells, which are listed in Table 2, are considered to have water level data that more accurately <br />depict seasonal trends in water levels in the parts of the aquifers where those wells are located. <br />The other wells monitored semi-annually continue to provide valuable data for long-term <br />trends. <br />SPDSS Phase 4 Task 39 Technical Memorandum-Final <br />O~i20%2008 <br />