OR 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.
- Annular seal
- The grout placed in the space between the borehole wall and the well casing to prevent contamination and cross-aquifer flow; must be at least 6 inches thick in Oregon.
- Pitless adapter
- A device that allows the pump discharge pipe to pass through the casing below the frost line, eliminating the need for a well pit and reducing contamination risk.
- Sanitary seal
- A watertight, vermin-proof cap or seal at the top of the well casing that prevents surface water and contaminants from entering the well.
- Grout placement
- Grout must be placed by tremie or positive displacement from the bottom up to avoid voids and ensure a continuous seal; free-falling is prohibited.
- Well development
- The process of removing drilling fluids and fines from the aquifer around the screen to improve yield and water quality; continued until water is clear and sand-free.
- Disinfection
- A required procedure using chlorine (e.g., 50 mg/L for 24 hours) to kill bacteria in a new or repaired well before it is placed into service.
- Abandonment procedure
- Filling an unused well with grout from bottom to top using a tremie pipe; the top 5 feet may be filled with compacted bentonite or concrete.
- Minimum setback distances
- Oregon requires at least 50 feet between a well and a septic tank or sewer line, and 100 feet from a drainfield or livestock enclosure.
- Prior appropriation
- The doctrine that water rights are granted based on the date of first beneficial use: first in time, first in right; senior rights are satisfied before junior rights.
- Water right permit
- A document authorizing construction and use of water but not a vested right; a certificate is issued after proof of beneficial use within the specified time.
- Beneficial use
- The actual application of water to a beneficial purpose (e.g., irrigation, domestic supply) without waste; required to perfect a water right.
- Duty of water
- The amount of water needed for a specific use, often expressed as a rate per acre (e.g., 1/80 cfs per acre for irrigation in eastern Oregon).
- Exempt use
- A water use that does not require a permit, such as domestic use up to 15,000 gallons per day, but must still be registered and is subject to regulation.
- Certificate of water right
- The final document confirming the priority date, amount, point of diversion, and place of use after beneficial use has been proven.
- Regulation of junior rights
- During shortages, junior water right holders may be shut off to satisfy senior rights, following the priority system.
- Transfer application
- A request to change the point of diversion, place of use, or type of use of an existing water right; must show no injury to other rights.
- Public interest review
- A review required for new water right permits and transfers to ensure the proposed use will not impair the public interest.
- Darcy's law
- Q = K × i × A, where Q is discharge, K is hydraulic conductivity, i is hydraulic gradient, and A is cross-sectional area.
- Transmissivity
- The rate at which water is transmitted through a unit width of aquifer under a unit hydraulic gradient; equal to hydraulic conductivity times saturated thickness (T = K × b).
- Storativity
- The volume of water an aquifer releases from storage per unit surface area per unit decline in head; for unconfined aquifers, it approximates specific yield.
- Theis equation
- s = (Q / (4πT)) × W(u), where u = (r²S)/(4Tt); used to calculate drawdown in a confined aquifer under transient conditions.
- Cooper-Jacob approximation
- A simplified form of the Theis equation valid for small u (u < 0.01): s = (2.303Q/(4πT)) × log10(2.25Tt/(r²S)).
- Specific capacity
- The pumping rate divided by the drawdown in the well; it decreases with pumping time and is used to estimate well efficiency.
- Well efficiency
- The ratio of theoretical drawdown to actual drawdown, expressed as a percentage; typical values for properly developed wells are 60% to 80%.
- Radius of influence
- The radial distance from a pumping well where drawdown is negligible; can be estimated empirically as R = 3000 × s × √K.
- Static water level
- The level of water in a well when the pump has been off long enough for the water level to stabilize; used as a baseline for drawdown measurements.
- Pumping water level
- The water level in a well while the pump is operating; measured after pumping has stabilized, typically after 24 hours.
- Water Well Report
- OWRD Form WW-1, required within 30 days of well completion, modification, or abandonment; includes construction details, yield test data, and driller's signature.
- Well contractor licensing
- Oregon requires water well contractors to be licensed by the Oregon Construction Contractors Board and hold a Water Well Contractor license from OWRD.
- Report distribution
- A copy of the completed well report must be provided to the well owner within 30 days of completion.
- Recordkeeping
- Well contractors must keep records of construction, alteration, and abandonment for at least 5 years and make them available for inspection.
- Civil penalties
- Failure to submit a well report or comply with construction standards may result in civil penalties up to $5,000 per violation per day.