Minor head losses in well piping: if h is the friction loss in the pipe, the combined losses in the strainer and bends may be taken approximately as

Introduction / Context:
Design of well assemblies and pumping lines requires accounting for both major (friction) and minor (local) head losses. Strainers, screens, and bends contribute additional losses that must be included for accurate drawdown and pump sizing.

Given Data / Assumptions:

• Major loss in the line is represented by h (Darcy–Weisbach or Hazen–Williams–based).
• Minor losses arise from entrance/exit, screens/strainers, elbows, tees, and fittings.
• Empirical practice suggests a fraction of h to cover these minor losses in preliminary estimates.

Concept / Approach:
While detailed design uses K-factors for each fitting (loss = K * V^2 / (2g)), preliminary groundwater design often approximates combined local losses as a percentage of the major loss. A typical allowance of about 20 percent of h is used for strainers and bends together.

Step-by-Step Solution:
Start with friction loss h computed for the pipeline length.Estimate combined local losses ≈ 0.2 * h for strainer and bends.Total dynamic head then becomes h + 0.2h = 1.2h (plus other components as applicable).

Verification / Alternative check:
Cross-check with individual K-values for the specific fittings; the sum often lies in the same order as 15–30% of the friction loss for typical well columns and discharge heads.

Why Other Options Are Wrong:
0.01h is negligible; 0.45h, 0.25h, 0.30h are larger assumptions suited only to unusually loss-intensive layouts and are not standard quick estimates for screen plus a few bends.

Common Pitfalls:
Ignoring minor losses entirely; using a blanket percentage without checking unusually numerous fittings or small-diameter/high-velocity cases.

Final Answer:
0.20 h.