If a pipe gets old and rougher, how does that change the 'system head curve' for water being pumped through it?

When a pipe gets old and rougher, it fundamentally changes the 'system head curve' by increasing the energy required to pump water through it at any given flow rate. The 'system head curve' is a graphical representation that shows the total head, or energy per unit weight of fluid, that a piping system requires to move fluid at various flow rates. This total head is comprised of several components: static head (due to elevation differences), pressure head (due to pressure differences), velocity head (due to the fluid's kinetic energy), and most importantly for this question, friction head loss.