Video 15 Apr

Meet the Hydrogeologist {Mark W. Eisner} Talk (April 15, 2013)


Overview of Presentation

Options for the Project

Spring Impoundment: cost known, do field work in dry season, no driller needed, location guided by observation (rivulets)

- Groundwater Borehole (Best Option): requires specialized training & equipment , need plan for uncertainties (i.e. cost, depth, design), drought/sanitary protection, want to account for possible cracks in borehole

GW Recharge originates from precipitation

- Borrowing storage may be necessary

How to build a borehole

- Screening above the rock (Saprolite)

- Casing off the saprolite (Bedrock Borehole) - Best Option

    ~ Water comes from fractures, cheaper option, drought/sanitary protection 

What to look for:

Change to a beige color

- Voids underground 

- Rate of penetration is increasing

*Know how the other wells are built and how well they perform


 - Consider protection from contaminants

     ~ Account for casing below, possibility of turbidity that may bring more bacteria/pathogens, guarantee clear, colorless stream of water

Project design considerations

   - Work in the dry season

   - Drill deeper than you think

   - Large borehole diameter improves reservoir

   - Clear and colorless quality

Question and Answer Session

 Q: What might you do if you drill and you have bacteria or contamination after the quality test?

A: Chlorinate the well and perform a test pump assessment, then resample

Q: Why steel over PVC casing?

A: Plastic has greater odds of cracking. You want to send the bottom of the pipe as hard against the rock as possible to minimize potential leakages and contaminants around the pipe and into the well

Q: What other precautions to think about?

A: Drill deeper than you need/know. Chlorinate as soon as the drilling is done. The shallower the well you encounter, the larger you might want to make the diameter of the well (if your height is too small).

Q: Are there any design rules dealing with the diameter of the well?

A: Yes….[you need to take into consideration] how many people are gonna use it? 570 people…20, maybe 10 gallons per day per person?



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Contribution made to EWB by Laetitia Mulamula, Eric Smith, Robert Hackman, Theodore DeBoda, William Wojcik (UMBC Department of Chemical, Biochemical and Environmental Engineering), Lee Blaney. Thank you so much!