The answer to 'why is my sprinkler system erosion' is that sprinkler system erosion is typically caused by water pressure issues, leaks, or improper installation. This can lead to soil erosion around the sprinkler heads, pipes, and valves, creating divots and channels in your lawn. Symptoms include visible damage, pooling water, and reduced sprinkler coverage.
To fix sprinkler system erosion, you'll need to identify and address the root cause. This may involve adjusting water pressure, repairing leaks, or re-leveling and re-sodding affected areas. If the issue is due to poor installation, you may need to call in a professional landscaper or sprinkler technician to make the necessary repairs.