Which of the following is included in the repair of water wells?

The process of repairing water wells often includes a variety of tasks aimed at restoring or enhancing the functionality of existing wells. Changing casing and screen depths is a common repair practice because the casing provides structural integrity to the well and protects it from contaminants, while the screen allows water to flow in while keeping out sediment and debris. Over time, these components may become damaged, clogged, or otherwise compromised, necessitating adjustments or replacements to ensure optimal water access and quality.

Other options do touch on relevant aspects of water management, but they do not pertain directly to the repair of existing wells. Drilling new wells is a separate process that addresses situations where the current well may no longer be viable, rather than repairing an existing structure. Installing new water purification systems focuses on treating water quality issues rather than repairing the well's physical structure. Conducting surveys of aquatic life is related to ecological assessments and does not involve the mechanical or structural repair of water wells. Therefore, the focus on adjusting casing and screen depths is a clear indication of repair work on existing wells.