IL Well Driller flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Rotary drilling circulation
- Drilling fluid is pumped down the drill pipe, out through the bit, and back up the annulus, cooling the bit and carrying cuttings to the surface while stabilizing the borehole wall.
- Cable-tool drilling
- A percussion method in which a heavy bit is raised and dropped to break rock; cuttings are removed with a bailer, and the borehole is kept open by casing advanced behind the bit.
- Casing height above grade
- The well casing must extend at least 12 inches above finished ground surface or above the floor of a pit, so that surface water cannot flow into the well.
- Pump-and-treat grouting
- Grout is pumped from the bottom of the annular space upward through a tremie pipe, displacing water ahead of it, which produces a continuous seal without voids or bridging.
- Well screen sizing
- Screen openings are chosen from sieve analysis of the aquifer material so the screen retains most formation sand while allowing water to enter with minimal head loss.
- Artesian flowing well control
- A flowing well needs a control valve and a sealed casing annulus so discharge can be regulated and shallow and deep aquifers are not connected through the borehole.
- Well-to-septic tank setback
- In Illinois, a private water well must be at least 50 feet horizontally from a septic tank and at least 75 feet from the septic absorption field.
- Well-to-sewer setback
- A well must be at least 50 feet from a sanitary sewer line and at least 25 feet from a storm sewer or drainage ditch, with casing raised above flood level where needed.
- Privy and cesspool setback
- A well must be at least 75 feet from a privy, cesspool, or pit latrine, and at least 50 feet from a livestock yard or animal confinement area.
- Minimum grout seal depth
- The annular grout seal extends from the top of the well to at least 25 feet below ground surface, and deeper where a shallow aquifer must be protected.
- Neat cement grout mix
- Neat cement grout uses no more than 6 gallons of clean water per 94-pound sack of cement; excess water weakens the seal and causes shrinkage and bridging.
- Grout volume calculation
- Annular volume equals the cross-sectional area between borehole wall and casing times the seal length, multiplied by an excess factor of about 1.1 to 1.5 for washouts.
- Shallow aquifer isolation
- When a well is completed in bedrock beneath a shallow aquifer, casing and grout must seal off the shallow aquifer so the two water-bearing zones remain hydraulically separate.
- Well development purpose
- Development removes drilling fluid, fines, and filter cake from the borehole and screen, improving yield and producing sand-free water at the design pumping rate.
- Surging and jetting
- Surging moves water back and forth through the screen to loosen fines; jetting directs high-velocity water at the screen; both are followed by pumping to waste.
- New well disinfection dose
- New wells are disinfected with a chlorine solution giving at least 50 mg/L free chlorine throughout the water column, held at least 12 hours before pumping to waste.
- Chlorine residual before sampling
- The well is pumped to waste until the chlorine residual is gone; a bacteriological sample collected while residual remains will be invalid for coliform testing.
- Total dynamic head
- Total dynamic head is the sum of static lift, drawdown, discharge pressure head, and friction losses; pump selection must match it to the well yield.
- Pitless adapter function
- A pitless adapter carries the discharge line through the casing below the frost line, allowing a watertight sanitary cap at the surface without a pit.
- Well abandonment sealing
- An unusable well is disinfected, cleared of obstructions where practicable, and filled from the bottom up with grout or clean impermeable material, with a record filed.
- Sand-free production criterion
- A well is considered developed when it yields water free of measurable sand at the design rate and turbidity has stabilized, not merely when it first runs clear.
- Illinois code authority
- The Illinois Water Well Construction Code is administered by the Illinois Department of Public Health, which sets construction, sealing, and pump installation requirements.
- Separate driller and pump licenses
- Illinois issues a Water Well Driller license and a Water Well Pump Installation license as separate credentials; work must be done under the responsible licensee.
- Well completion report
- A driller's log filed with the Department records well location, depth, geology, casing, grout, screen, static water level, and yield for each completed well.
- Sanitary well cap requirement
- The well must have a watertight, vermin-proof sanitary cap; a missing or loose cap is a construction deficiency that allows surface contamination into the well.
- Backflow and cross-connection
- A well discharge may not connect to a system carrying nonpotable water without an approved backflow prevention device, protecting the aquifer from contamination.
- Coliform sample handling
- Bacteriological samples are collected in sterile containers after disinfection and chlorine dissipation; a confirmed total coliform positive requires investigation and corrective action.
- NSF/ANSI Standard 61
- Materials and equipment that contact drinking water must meet NSF/ANSI Standard 61 or an equivalent health-effects standard to limit leaching of contaminants.
- License discipline authority
- The Department may suspend or revoke a license for code violations and may order a well repaired or sealed when it threatens the aquifer or public health.
- Floodway siting prohibition
- A well may not be sited in a floodway or in a pit that collects surface water, and casing must be raised above the expected flood level.
- Wellhead foundation clearance
- Wells are kept at least 10 feet from building foundations and property lines unless a stricter local ordinance applies, so the grout seal and cap can be maintained.
- Overpumping development
- Overpumping develops a well by pumping at rates above design to draw fines through the screen; it continues until sand content and turbidity stabilize at acceptable levels.