MA Well Driller flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Specific capacity

Pumping rate divided by drawdown, usually reported in gallons per minute per foot. It ranks well performance and declines as a well plugs, so it is measured during the yield test.

Static water level

The undisturbed water level in a well measured before pumping begins. It is the reference point for computing drawdown and for setting the pump depth.

Zone I radius

The innermost wellhead protection area: 400 feet for a public well, 100 feet for a private well. Most land uses that could contaminate groundwater are restricted inside it.

Tremie grouting

Placing grout through a pipe kept submerged in the rising grout column so it fills the annulus from the bottom up. It prevents bridging and voids that would let surface water reach the aquifer.

Annular seal

The grouted space between the borehole wall and the casing. It blocks the vertical pathway along the casing that would otherwise carry surface contamination directly to the water-bearing zone.

Sanitary well cap

A vermin-proof, vented cap that seals the top of the casing while allowing air exchange. A missing or damaged cap is a direct opening for insects and surface water.

Neat cement grout

Cement mixed with water only, without sand. It sets strong and low-permeability and is preferred for deep casing, though its heat of hydration can damage PVC in large volumes.

Bentonite grout

A clay-based slurry that swells and seals the annulus. It is low in permeability and useful in dry holes, but it must be mixed and placed correctly to avoid shrinking or settling.

Well development

Removing drilling mud, fines, and debris from a new well by surging, jetting, bailing, or airlifting. It raises specific capacity and continues until discharge runs clear and sand-free.

Gravel pack

Clean, washed sand or gravel placed in the annulus around a screen. It enlarges the effective well radius and filters formation fines, and is sized about four to six times the formation grain diameter.

Screen slot size

The opening size of a well screen, chosen to retain roughly half to sixty percent of the formation material. Too fine plugs with fines; too coarse passes sand and damages the pump.

Driven point well

A shallow well made by driving a screened pipe into unconsolidated sand or gravel. It has no grouted annular seal, so it is unsuitable where contamination is likely.

Casing height above grade

Massachusetts requires the well casing to terminate at least 18 inches above finished grade. The height keeps surface water and runoff from entering the wellhead.

Steel casing bedrock seating

Steel casing must extend at least 10 feet into competent bedrock. This seats the casing in solid rock and seals off the overburden and its downward water pathways.

Pressure tank precharge

The air pressure in a captive-air tank, normally set about 2 psi below the pump cut-in pressure. Correct precharge lets the tank store water and prevents rapid pump cycling.

Pressure switch differential

The difference between cut-in and cut-out pressure, commonly 20 psi for a bladder tank. It determines how much water the tank delivers per pump cycle.

Shock chlorination

Disinfecting a well by adding chlorine solution to at least 50 to 100 ppm, circulating it, holding 12 to 24 hours, then flushing. Coliform is retested after flushing.

Chlorine contact time

Disinfection depends on both chlorine concentration and the time it stays in contact with the well. A quick flush does not disinfect; the solution must remain in the well for hours.

Submersible pump setting depth

Set the pump at least 10 feet below the lowest anticipated pumping level and at least 5 feet above the well bottom. This avoids cavitation and sediment intake.

Pump performance curve

A graph of flow versus head for a pump. Design flow should fall in the middle of the curve, not at shutoff or maximum flow, for efficient operation.

Well completion report

The required record filed after drilling, documenting location, depth, casing, grout, water levels, yield test, and water quality. It is filed with the state and the local Board of Health.

Yield test

Pumping a new well at a steady rate for a defined period while recording static and pumping levels. The results give drawdown and specific capacity for the completion report.

Board of Health permit

The local permit required before drilling a private well in most Massachusetts towns. The driller must obtain it and keep it available on site during construction.

Well driller license

Massachusetts requires a license, administered by MassDEP, to construct, alter, or abandon a well. Drilling with a lapsed or absent license is prohibited.

Public water supply well

A well serving the public, regulated under 310 CMR 22.00. It requires MassDEP approval, a wellhead protection area, and source water assessment before use.

Abandoned well sealing

Removing obstructions, disinfecting, and filling the entire well with approved grout or clean fill capped with grout. Merely capping or rubble-filling a well is not acceptable.

Nitrate MCL

The maximum contaminant level for nitrate is 10 mg/L as nitrogen. Higher levels indicate septic, fertilizer, or manure influence and pose a risk to infants.

Arsenic MCL

The maximum contaminant level for arsenic is 10 micrograms per liter. In Massachusetts it occurs naturally in some bedrock wells and requires treatment when exceeded.

Coliform bacteria result

Total coliform indicates a possible pathway for pathogens; E. coli indicates fecal contamination. Either requires disinfection, retesting, and investigation of the source.

Corrosive water

Water with pH below about 6.5 can leach lead and copper from plumbing. Treatment with a neutralizing filter or soda ash feed raises pH and protects the system.

Confined space entry

A well pit not designed for continuous occupancy is a permit-required confined space. Test for oxygen deficiency and toxic gas, then use a harness and tripod before entry.

Call 811 before drilling

The free utility locate service must be contacted before drilling or excavating. It marks underground gas, electric, water, and communications lines to prevent strikes.