# Shared Flashcard Set

## Details

ASBOG STUDY / Various Equation
A flashcard set of equations found in the ASBOG study booklet.
45
Geology
02/08/2021

Term
 Sy = (Vw/Vt)100
Definition
 Specific Yield (unitless)(water volume lost / total soil volume)
Term
 Specific Yield
Definition
 Ratio of volume water to volume total soil which drains under gravity.
Term
 Specific Yield
Definition
 approx. equal to effective porosity (ne) in unconfined aquifers.
Term
 Sr = (Vw/Vt)100
Definition
 Specific Retention(volume water retained / total soil volume)
Term
 Specific Retention
Definition
 Ratio of the volume of water retained to total volume of soil.
Term
 S = ±Vw / (Aδh)
Definition
 Storativity of an unconfined aquifer(water volume / area x change in head)
Term
 Storativity
Definition
 (~0.01-0.3, unitless)vol. of water an aquifer releases or intakes per unit surface area per change in head.
Term
 S = b Ss
Definition
 (~0.001-0.00001, unitless)Storativity of a confined aquifer(aquifer thickness x specific storage)
Term
 K = ki(γ/μ)
Definition
 Hydraulic Conductivity(intrinsic permeability x (specific weight / dynamic viscosity))
Term
 hydraulic conductivity
Definition
 gpd/ft^2
Term
 T = Kb
Definition
 Transmissivity(hydraulic conductivity x aquifer thickness)
Term
 Transmissivity
Definition
 gpd/ft or ft^2/day
Term
 i = (h1 - h2)/l
Definition
 Hydraulic Conductivity(change in head between two points / length between two points)
Term
 hydraulic conductivity
Definition
 unitless
Term
 So = 1 - Sw
Definition
 Saturation of oil(1 - unit water saturation)
Term
 STO = (A t φ R So) / FVF 5.615
Definition
 Recoverable stock-tank oil (barrels)
Term
 dSt = P - E ± R ± U
Definition
 Hydrologic Budget
Term
 hydrologic budget
Definition
 change in total storage of an aquifer(AcreFeetperYear AFY)
Term
 dS = I - O
Definition
 Change in aquifer storageinput - output
Term
 Recoverable stock-tank oil
Definition
 barrels((area x thickness x porosity x recoverability factor x oil saturation) / (formation volume factor x 5.615))
Term
 E = z1 - z2 = h
Definition
Term
Definition
 difference of hydraulic head between two points (z1, z2).
Term
 n = (Vv/Vt)100
Definition
 porosity
Term
 porosity
Definition
 unitless %void space volume / total volume
Term
 ne = (Ws-Wr)/(Ws-Wo) x (Vv/V)100
Definition
 effective porosity
Term
 Q = K i AorQ = T i w
Definition
 Groundwater flow (confined aquifer)
Term
 Groundwater flow (confined aquifer)
Definition
 ft/day or gpd/ft^2Can solve with either hydraulic conductivity or transmissivity
Term
 Q = (-1/2) K ((ha^2 - hb^2)/l) l
Definition
 hydraulic flow in an unconfined aquifer
Term
 Vs = Ki/ne
Definition
 Groundwater seepage velocity
Term
 Groundwater seepage velocity
Definition
 gpd/ft^2
Term
 SAR = Na / √((Ca+Mg)/2)
Definition
 Sodium Absorption Rate
Term
 sodium absorption rate
Definition
 2-10 low risk>11 high riskused to measure hazardous sodium in the soil
Term
 hardness = (Ca mg/L) + (Mg mg/L) x 50
Definition
 hardness of the water
Term
 V1 / V2 = Sinα / Sinβ
Definition
 Snell's Law of geophysical seismic wave refraction
Term
 t = x/V2 + ((2d√(V2^2 - V1^2))/V1xV2)
Definition
 Snell's Law as a Two Layer problem; solving for time
Term
 d = tiV1V2 / 2√(V2+V1)
Definition
 Snells Law; two layer; calc. depth from graphti = intercept time
Term
 d = √(V2-V1) / (2√V2+V1) x Xcross
Definition
 Snell's Law; two layer problem; solving d calculate layer depth from graphical Xcross distance.
Term
 Cn = 1/√(σv)Ncorrected = Cn x Nf
Definition
 Field correction factor Cnσv represents effective overburden factorThen field blow count x field correction factor to solve for Ncorrected
Term
 T = 35Q/dsorT = 264Q/ds
Definition
 Transmissivity for time-drawdown graphft^2/dayorgpd/ft
Term
 S = T to / 640r^2orS = T to / 4790r^2
Definition
 Storativity via transmissivity for time-drawdown graph.ft^2/dayorgpd/ft
Term
 T = 70Q/dsorT = 528Q/ds
Definition
 Transmissivity for depth-drawdown graphft^2/dayorgpd/ft
Term
 S = Tt/640ro^2orS = Tt/4790ro^2
Definition
 Storativity via transmissivity for depth-drawdown graph.ft^2/dayorgpd/ft
Term
 WE = St/Sa x100
Definition
 Well efficiency = theoretical drawdown/actual drawdown
Term
 ρdry = ρ / 1+ω
Definition
 calculating dry density = given density / 1 + water content
Term
 relative compaction = ρdry / ρmax
Definition
 calculating relative compaction of a soil w/ a given maximum dry density from a compaction curve
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