September 2007

Information from Recent ‘Hydrology Study’ by GGI for EAWSD

The Long-Term Water Availability and Well Field Management Study Report (the ‘Hydrology Study’) was recently completed by Glorieta Geoscience, Inc. (GGI) under contract to EAWSD. A summary of the main issues and conclusions was presented to the Board of Directors on July 17; and a similar summary was presented to the public on July 24. Copies of the non-technical Executive Summary of the report were also available to the public at the July 24 presentation.

There were four key elements of the project:

1. Study of the current EAWSD  wells and aquifers.

2.    Evaluation of well operations and well improvements to increase production and extend  the life of existing wells.

3.    Identification of prospective sites for new wells and wells developed by others that could be acquired.

4.    Development of a groundwater model to assess well field performance and 

       long-term water availability.

The study used previous geophysical, geologic and hydrologic investigations, including the results of previous well drilling and testing programs undertaken in the Eldorado area to build a groundwater flow model and evaluate management of the wells and aquifers, including sustainable rates of groundwater withdrawal.

The study addressed the following issues:

a. Primary aquifers underlying the Eldorado area.

b.  The aquifers’ long-term (40 to 100) year response to withdrawal of groundwater from the District’s existing and proposed wells.

c.   Projected decline in well yields and drawdowns, due to pumping.

d.  The practical lifetime of each District well currently in production.

e.  A well replacement and well addition schedule.

Current demand and water production for the past couple of years has averaged 500 to 600 acre-feet/year (“afy”). This was used as a baseline analysis of Eldorado water needs and three scenarios were developed:

1.  Using existing EAWSD wells, only, while trying to meet existing 600 afy demand over the next 40-100 years.

2.  Using existing EAWSD wells plus new and acquired wells, as required, to meet 

     a defined 600 afy demand, plus a proper level of reserve pumping capacity. 

3.  A futuristic scenario to meet an increasing demand schedule from 600 to

     1160 afy over 100 years---based on assumed projections of future hypo-

     thetical development in the area---which are basically unknown at this at this   

     time.

Each scenario resulted in consequences and conclusions from continued groundwater harvesting and recommendations to EAWSD:

¨ The study concluded that pumping existing wells alone, including the new Well #17, would have insufficient production capacity, over time, to meet 600 afy demand. Additional wells would be needed to meet the current demand level of 600 afy and to furnish the proper reserve capacity.  As wells age and water levels decline, a well replacement and well addition schedule would be necessary. 

¨ The District could meet 600 afy demand, with 200 gpm reserve pumping capacity, by the addition of 6 new wells (beyond the new Well #17) in the next few years.   The available geohydrologic data indicate that the District should be able to extend its central well field deeper and modestly outwards to obtain sufficient groundwater to maintain acceptable levels of service to its existing customer base for more than 100 years.  With six new wells, production could be maintained at 600 afy for more than 100 years.  Adding the new wells would allow the District to reduce pumping from its older wells, thereby extending their service life.

¨ As to future development, there  MAY be sufficient groundwater in storage in aquifers underlying the Eldorado area to reach higher demand levels, but it involves many risks. To produce at the higher hypothetical level of 1160 afy would require drilling of, at least, 19 additional wells, most of them by 2022, which would likely be impractical due to cost considerations and the close spacing of so many wells.

SUMMARY:  The study by GGI concludes that there is sufficient groundwater in the Eldorado area to supply current demand levels of 600 afy for the next 100 years, with the addition of, at least, six new wells to the EAWSD infrastructure to furnish adequate pumping capacity, including proper reserves. GGI also has made several recommendations for management of the wells and the well field. These recommendations all are under advisement, and will be implemented by the EAWSD Board as time and money permits.  The GGI Report provides a complete, up-to-date assessment of the groundwater conditions and availability to EAWSD ratepayers.  It focuses on current water demand and well requirements for that demand level; however, it can be used as a guide for future projections.  A copy of the Executive Summary can be obtained from EAWSD and the full report is available for review by anyone interested through arrangement with the General Manager at the EAWSD Office.

New EAWSD President

James Jenkins was elected as the new President by the EAWSD Board at the Special Board Meeting on 21 Aug 2007.  In the new President’s own words:  The debate over water goes on around the world. Land and water decisions, price and quality issues, ownership, and what constitutes sound planning for the future are all of local importance. I saw an opportunity with our Water District to become involved with the most critical issue facing our communities. I was honored to be chosen to serve on the Board of Directors and then to be selected to serve our communities as President of the District.  Together, we have much work to do.  Water is essential to each of us.