22 JUNE 2021 WorldWide Drilling Resource® Environmental Monitoring by Thomas Kwader, Ph.D., P.G. Owner, Qwater Well Developer and WorldWide Drilling Resource® Hydrogeologist Well Specific Capacity - The Most Important Data to Collect From a New Well, Part 2 of 2 Last month’s article focused on the importance of collecting data regarding the development of all newly drilled wells to document a baseline for future comparison of changes in well efficiency. There may be a number of reasons a well appears to “dry up” or become less efficient, including: 1) The well was drilled during a wet season with unusually high groundwater levels, which allowed “thicker” water zones to be available before cavitation of the pump occurs; 2) Lower than “normal” rainfall conditions that do not allow the aquifer to rise to water levels at the time the well was drilled; 3) If an additional well(s) was installed nearby, the new well(s) could be contributing to lowering the water table to historically low levels; and, 4) The plugging of the screen with fine-grained materials and/or bacterial growth of algae or “slimes” in the well (chemical treatment and/or redevelopment may fix this problem). In last month’s article, the importance of collecting information on the Specific Capacity of the new well was discussed. Specific Capacity (SC) is the amount of drawdown the water level in the well at a given pumping rate, expressed as: gpm (gallons per minute) pumped divided by the amount of drawdown in the well in feet (ft) or: SC = gpm/ft, (when the water level stabilizes) If the original Specific Capacity of the well is known, then the reason for the well “going dry” can be narrowed to either being a “well plugging problem” or due to declining water levels in the area. If water levels are declining over time, the fix to obtain more water may include lowering the pump, pumping at a lower rate (but pumping more hours per day to maintain a steady flow rate), or to drill a deeper new well farther away from the existing wells. If water levels are not showing declines in the area, the well may need to be chemically treated and/or physically redeveloped (surged and pumped hard) to reopen the “flow paths” near the borehole. Tom TomKwader may be contacted via e-mail tomichele@worldwidedrillingresource.com 302-684-3197 FAX: 302-384-0643 142 Broadkill Rd. • Milton, DE 19968 www.atlantic-screen.com email: atlantic@ce.net Manufacturers of Slotted & Perforated Pipe ranging from ½” to 24” diameter Atlantic Screen & Mfg., Inc. • Well Rehab. Products • Manholes • Bentonite • Filter Sock • Inline Chemical Mixers • Sampling Bailers • Clear PVC Pipe • Locking Caps ENV LOOK!!! Our Mailbox is overflowing with letters from happy readers! Here are just a couple! Your magazine is really great. Thank you, and keep up the good work. Paul Cedar Falls, IA Great resource! Thank you. New Subscriber in Exeter, CA
RkJQdWJsaXNoZXIy NDk4Mzk=