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| Type: |
Potable Water |
| Project Manager: |
Brad T. Blais, P.E. |
| Owner: |
City of Deland |
| The study at Victoria Park Water Treatment Plant was primarily focused on four main wells.
Test Well #1: This well had the best transmissivity with only 4.75 feet of drawdown at 110 gpm. The static potentiometric surface is near the highest in the property. There may not be as much clay in this area to restrict impacts to the surficial aquifer. Water quality was excellent with the exception of iron at 0.75 ppm, well above its MCL of 0.30 ppm. Another adavantage to this site is its proximity to the proposed water plant. The black much found at 300 feet below the surface is a potential problem.
Test Well #2: This well has very good transmissivity with 5.77 feet of drawdown at 110 gpm. This area has the advantage of the highest potentiometric surface on the property. Iron was again a problem at 0.70 ppm. The drilling log noted some clay in the limstone, which could be a problem.
Test Well #3: Tranmissivity is slightly poorer with 5.88 feet of drawdown at 107 gpm, but the potentiometric surface is also lower than at TW#1 and TW#2. These factors in combination begin to limit the production capabilities of a well. Iron was very high at 1.78 ppm. Black much was encountered at 340 feet below the surface.
Test Well #4: Poor tranmissivity with 12.88 feet of drawdown at 106 gpm. Potentometric surface very low at 10 feet NGVD. Water quality was better in this location, but a municipal wellfield would not be possible in this area due to the other factors.
Any municipal wellfield should be restricted to the northeast part of the property. This is where the potentiometric surface is the highest and the tranmissivity is greatest. Here we can install 16-inch wells and get 100 gpm with acceptable drawdown. Water quality across the property is excellent with the notable exception of iron, which is more than twice its MCL in the northeast. Iron levels get very high in the middle of the property around TW #3, and this may restrict southern expansion of the wellfield. High iron can be handled in the treatment process, but it is expensive.
Suggestions made were to start plugging back Test Well #1 to 280 feet, running another pump test, and analyzing for iron. The only distinctive layer in the area is the black much, and by sealing this off it may improve the iron level. The pump test would indicate if any production would be lost by losing 70 feet of the hole. This project is relatively inexpensive, and could considerably help treatment costs. Since the tranmissivity levels are good the potentometric surface so high, there is room to maneuver. This would be a worthwhile trade-off to lose a little capacity if iron levels could be improved.
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