Laserfiche WebLink
2 <br />C:\Mounds View Part 1 WHPP\Attachment 1 Mounds View Scope of Work.docx <br /> <br /> The Wellhead Protection Rules require that data from aquifer tests be used to determine aquifer <br />hydraulic conductivity/transmissivity for use in developing Part 1 of the WHPP. It is our <br />understanding that the MDH will not require performance of a pumping test in the Mounds View <br />wells. Rather existing data from tests conducted during installation of one or more of the City’s <br />wells or the results of a test in a nearby well can be used to meet this requirement. If MDH later <br />determines that it is necessary to conduct a pumping test in one of the Mounds View wells we <br />will provide a cost estimate for the work at that time. <br /> Per the MDH requirement stated in the Scoping Decsion, the WHPA delineation for Well 5 will <br />include both porous media groundwater flow and fractured media groundwater flow evaluations. <br />Per the Scoping Decision, the need for both porous media and fractured media flow evaluations <br />for Wells 3 and 6 may be re-assessed at the Pre-Delineation Meeting. One or more of the <br />techniques described in the MDH document “Guidance for Delineating Wellhead Protection <br />Areas in Fractured and Solution-Weathered Bedrock in Minnesota” will be used to perform the <br />fractured media flow evaluation for Well 5. If MDH determines at the Pre-Delineation Meeting <br />that fracture flow evaluations must be performed for Wells 3 and 6, we will provide the City with <br />any additional costs for the evaluations prior to starting the work. <br /> In A pril 2010, Barr completed the Part 1 WHPP for the City of New Brighton. The work <br />included developing a groundwater flow model for the porous media flow evaluation for the New <br />Brighton wells. This groundwater flow model was developed from the Metro Model 2 that Barr <br />previously prepared for Metropolitan Council Environmental Services. We will use the model <br />developed for our work in New Brighton as the base groundwater flow model in this work. We <br />have assumed that some minor revisions to the model will be necessary to account for geologic <br />details in the vicinity of Mounds View, to update the steady state pumping rates for the Mounds <br />View wells, and to refine the model grid in the vicinity of the Mounds View wells. We have <br />assumed that the hydraulic conductivities in the model for the New Brighton WHPA delineation <br />are appropriate for the current work and, therefore, adjusting the model hydraulic conductivities <br />for the aquifers beneath Mounds View will not be necessary. In addition, we have assumed that <br />no changes will be made to model pumping rates for high capacity wells other than the Mounds <br />View municipal wells. The updated model will be used for the porous media groundwater flow <br />evaluation. Based on our experience in constructing the New Brighton groundwater model, we <br />have also assumed that the model we will use is sufficiently calibrated for the purposes of this <br />project and that no further calibration will be necessary. <br /> Based on our experience with preparing Part 1 WHPPs (most recently in New Brighton), we have <br />assumed that model sensitivity (a.k.a., uncertainty) analysis will be required by MDH. This <br />requirement will be verified at the Pre-Delineation Meeting. <br /> The Wellhead Protection Rules require that a Pre-Delineation Meeting with MDH staff be <br />conducted prior to delineating the WHPA. The purpose of the meeting is to discuss the model to <br />be used to perform the porous media flow evaluation and the technique to be used for the <br />fractured media flow evaluation. We have assumed that this meeting will be held at Barr’s office <br />and will last no more than two hours.