image002Mammoth Community Water District Well Profiling Complete


December 1, 2014 – The Inyo-Mono Integrated Regional Water Management (IRWM) Program and the Mammoth Community Water District (MCWD) are pleased to announce the completion of the fieldwork portion of the Phase I Well Rehabilitation Project.  This project was funded through a Proposition 84 Integrated Regional Water Management Implementation Grant administered by the California Department of Water Resources and consisted of profiling one of the MCWD groundwater wells by a contracting hydrogeologist.  Well profiling is a relatively new technology that can evaluate the quality and quantity of water from different aquifer layers in a well.


MCWD supplies the community of Mammoth Lakes with drinking water from surface water and groundwater resources.  Groundwater comprises the majority of supply when surface water supply is limited due to a combination of low runoff, high demand, or stream bypass flow requirements.  MCWD treats all surface and groundwater supplies to ensure that state and federal standards for drinking water are met.  MCWD applied for grant funding to profile a well that contains constituents that interfere with the removal of arsenic at the water treatment plant.


The well profiling took place in September 2014 and was accomplished in three days.  The first day consisted of video surveillance of the well bore hole using a camera only ¾” diameter.  The video is used to get a general sense of the construction of the well and the diameter of the bore hole at various depths.  On the second day, work was performed to create a dynamic flow profile of the well.  In this process the contractor uses dye to trace flow direction and velocity within the well.  On day three, actual water samples are extracted from various depths within the bore hole.  A total of 11 samples were taken at a maximum of 30 feet apart.   Samples were sent to a water quality laboratory for in-depth water quality analysis.

The contractor will pair the water quality data with flow readings at each of the sampling locations.  This information will provide the MCWD with an understanding of whether water quality varies at different depths and how much the different water bearing layers contribute to the total well production.  The contractor will use this information to present recommendations to MCWD to improve the overall water quality in the well. Recommendations may include sealing off layers that contribute constituents that interfere with treatment, changing pumping rates, or a combination of measures.  The contractor will provide a report on the project to MCWD by the end of 2014.


Proposition 84 was approved by voters in 2006 to support water supply, water quality, and natural resource protection efforts.  This funding was provided through the Inyo-Mono IRWM Program, which has been working to identify water-related needs and secure funding for water projects in the region since 2008.  In 2011, the Inyo-Mono IRWMP was awarded a grant of $1,075,000 to fund seven on-the-ground projects that support improvements in water supply and water quality in Inyo and Mono Counties.  Other project locations include Coleville, Swall Meadows, Round Valley, Lone Pine, Laws, Independence, Aspendell, and Mammoth Lakes.  For more information about the projects, visit


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