2019-01-23_REVISION - M2014043 - Laserfiche WebLink

Home Browse Search

Albert Frei & Sons, Inc. Page 3 Hatchery Pit Permit # M-2014-043 Revised 1/16/19) The following table shows the proposed trigger elevations for each well now that site specific information is available. On Stage 1 the trigger point elevations were based on plus or minus 2 feet of change. In Stage 2 the maximum is based on the maximum elevation measured, pre-dewatering, in each monitoring wells and added 2 feet . The minimum was picked as 1 foot above bedrock since there are no surface wells within 800 feet of the dewatering area that would be impacted. The water table is normally 30 plus feet below the surface. Table Gm1 MONITORING WELL MWO1 MW-02 MW-03 MW-04 MW-05 MW-06 MW-07 BEDROCK ELEVATION 5065.8 5064.7 5066.4 5063.1 5063.0 5047.3 5037.67 TOP OF LINER ELEVATION 5081.5 5082.0 5080.0 NA 5071.2 5068.4 NA BOTTOM OF FRENCH DRAIN 5078.0 5078.0 5076.0 NA NA NA NA ELEVATION TRIGGER ELEVATION MAXIMUM 5080.0 5082.3 5081.7 5068.7 5068.46 5067.5 5066.3 TRIGGER ELEVATION MINIMUM 5066.8 5065.7 5067.4 5063.94 1 5063.14 5062.57 1 5061.67 The possibility of adjusting the baseline ranges if needed in the future will be discussed between the Division and the operator at that time. The baseline range changes would be documented with a Technical Revision. If the groundwater levels in a monitoring well pass their trigger points for more than 3 months in a row, the operator will investigate to determine causes, and do mitigation as necessary. The operator will notify the Division of the trigger investigations and any subsequent mitigation. A neighbor complaint could also be a "trigger" . Examples of possible issues that may cause a trigger are: water well levels low, flooding fields, and vegetation suffering. Albert Frei & Sons would investigate to determine causes and mitigate if necessary as needed following the mitigation plan outlined below. Mitigation Plan. If the trigger is reached based on data collected, the following actions should be undertaken: • An evaluation of the data to confirm that Albert Frei & Sons, Inc. (Frei) is responsible for the change shall be completed. • Implementation of mitigation measures . Mitigation measures that could be implemented (not necessarily in the order listed) include: Up Gradient Mitigation • In Stage 2 an inspection of the surface groundwater diversion drain (French Drain) on the outside the compacted liner will be done . If it is found there is a problem with the drain it will be cleaned or repaired as needed to preserve the drainage. Down Gradient Mitigation • Well improvements . Affected surface water wells could be deepened to bedrock or modified to increase yield. Alternatively, new alluvial wells could be constructed to provide a new water supply.