Question Statement:
Which of the following geometric and hydraulic properties of a flow net drawn for two-dimensional steady seepage through an isotropic earthen dam are correct?
```
Upstream Water Level ───┐
│ Flow Line Ψ1 ──────────────────────┐
├─── Flow Line Ψ2 ──────────────┐ │
Impermeable Core │ │ Equipotential Φ1 │ │
│ │ │ │ │
───────────────────────┴──────┴──────┴─────────────────┴─────┴── Impermeable Stratum
```
Options:
- (A) Flow lines (streamlines $\Psi$) and equipotential lines ($\Phi$) intersect orthogonally at right angles ($90^\circ$)
- (B) The basic flow fields formed between adjacent streamlines and equipotentials are curvilinear squares
- (C) The seepage discharge through each individual flow channel is identical ($\Delta q = k H / N_d$)
- (D) The total seepage quantity increases linearly with the number of potential drops $N_d$