| A |
cross-sectional area perpendicular to flow (L2) |
| α |
compressibility of the aquifer skeleton (T2LM−1) |
| β |
compressibility of water (T2LM−1) |
| C |
concentration in the stream water (ML−3) |
| Cg |
concentration in 100% groundwater (ML−3) |
| Cr |
concentration in 100% surface runoff water (ML−3) |
| D |
in Equation 2, mean pore size diameter for porous media or the pipe diameter (L) |
| D |
in Equation 4, hydraulic diameter of the pipe (L) (for circular pipe it is the pipe diameter, but for a non-circular pipe D = 2 times the square root of (A/π); where A is the cross-sectional area) |
| Δh |
measured head difference (L) |
| Δl |
length over which the head difference is measured (L) |
| Δp |
pressure difference between two ends of the pipe (ML−1T−2) |
| fD |
Darcy friction factor (dimensionless) |
| g |
local acceleration due to gravity or gravity constant (LT−2) |
| K |
hydraulic conductivity of the porous medium (LT−1) |
| L |
pipe length (L) |
| μ |
absolute or dynamic viscosity of water (ML−1T−1] |
| n |
porosity (dimensionless) |
| ν |
kinematic viscosity of water (L2T−1) |
| Q |
volumetric discharge (L3T−1) |
| q |
specific discharge (LT−1) |
| Qg |
groundwater portion of the total discharge of the stream (L3T−1) |
| Qr |
surface runoff portion of the total discharge of the stream (L3T−1) |
| r |
pipe radius (L) |
| Re |
Reynolds number (dimensionless) |
| ρ |
density of water (ML−3) |
| Ss |
specific storage (L−1) |
| V |
Q/A and is the mean flow velocity (LT−1) across a cross sectional area (also called Darcy velocity), which is equal to the volumetric flow, Q (L3T−1), divided by the cross-sectional area perpendicular to the direction of flow, A (L2) |
