PERMFILE121258 - Laserfiche WebLink

Home Browse Search

for such area, and the acreage of unlined pit floor. If the applicant elects to run the model both with and without mitigation measures to be employed, the applicant should be specific in quantifying the mitigation measures to be employed. Following such assessment, the applicant will need to describe the lateral and•vertical extent of the predicted groundwater impacts and the various offsite structures that will be affected, ie: high production imgation wells, shallow alluvial domestic wells, deep aquifer domestic wells, and wetlands dependent on shallow alluvial groundwater. 25. The applicant proposes a variety of mitigation measures on page 9 of the report. The applicant will need to quantify the specific mitigation measures to be employed, and specify the location(s) of where such measures will be employed, the length of time for the mitigation measures to be employed, volumes and quality of water to be involved in the mitigation, and how the appropriate volumes and quality of water will be delivered to the various mitigation locations. The applicant will need to specify any structures that will need to be constructed either on-site or offsite in order to deliver the mitigation water. The applicant will need to specify the monitoring measures that will be employed to provide assurance of delivery of the appropriate volume of water and quality of water to be used for mitigation. In addition to total suspended solids and pH, water quality testing will need to include parameters such as total dissolved solids, electrical conductivity, opacity, and palatability (for domestic wells). The applicant will also need to submit a specific map or exhibit which shows the location(s) and type(s) of mitigation measures to be employed. The applicant may also want to consider the use of French Drains between the various cells 26. Please clarify whether the post-construction (reclamation) simulation for predicted groundwater impacts considers the impacts to the groundwater system at a time when the compacted clay liner is completed for all cells. If not, the applicant will need to assess the potential groundwater impacts, such as mounding and/or shadowing, during such time. The assessment of impacts will need to describe the lateral and vertical extent of changes to the existing groundwater system and whether such impacts will intersect offsite structures such as Weld County Road 6, Weld County Road 27, Colorado Highway 85, building foundations, leach fields, shallow domestic wells, deep aquifer domestic wells, or high production irrigation wells. (Iri the event o~"adverse mounding effects, the applicant may want to consider the installation of French Drains in strategic locations.) 27. Please provide a specific map or exhibit showing the locations of all existing and proposed water monitoring locations, whether they be wells or peizometers, whether they be on-site or off- site. Please be sure to include the locations of the two (2) control points along the South Platte River. The specific monitoring locations should also be identified according to ownership and construction data such as diameter, total depth, and existing depth to groundwater. Although not required, the Division recommends the applicant also include a description of the location and horizontal distance to any other groundwater users that may cause interference of the monitoring well. The location of the 2 control points along the South Platte River should also be 28. Please revise the table of existing water monitoring data to include all baseline water monitoring data collected to date. The Division will require a full 12 months of baseline water level monitoring prior to initiation of de-watering activities. In the event a full 12 month set of