Question
Can a new drainage ditch effect the flow of an underground spring? I have a large rain water pipe that runs under my neighbor's driveway and pours water onto the top of property line which slopes down toward both of our lawns. To correct the standing water on both properties, I hired a grading company to dig a ditch following the downward slope along the property line and installed two 8" perforated pipes (laying side-by-side) on top of a bed of gravel. The grading company covered the pipes with gravel to be level with the lawn. At the end of the property line is a 2'x2' catch basin that fills and then spills into pvc pipes that drain into a lake at the end of the property. This expensive project has corrected the standing water issue (the neighbor even added an additional drainage pipe to the ditch). However, the neighbor now states that the drainage project has "changed" the water flow direction of an underground spring and their lawn is now always wet and soggy. The neighbor now wants me to correct this new issue. What do you think?

Answer
Hi Finn, Yes it could, but there are a lot of variables here that probably only an on site engineer can answer. How much grade change, etc? The spring...where was the water going before the work?  
Water follows the path of least resistance.  If the digging, or compaction from the weight of the equipment, closed that path, the water will take a new path of least resistance. Normally, I would expect the gravel to act like a French drain and help the situation, but it is conceivable that it didn't.
If the water is coming to the surface, then a drain pipe run from a catch basin there to your main drain should fix the problem.
Is this near where the standing water was previously?  Filling a low spot would alter the flow of water but if it is indeed a spring, it could have been soggy before and although you hate to think it, they may be wanting you to fix something that was already broke before the work.
An engineer could tell you pretty quick by a core sample if this is a new or old problem and may be worth the investment. It's also possible that your grading company may have some responsibility here.  If, and they should have, known about the spring, they should have made sure the water continued to flow properly.  
I'd start with your grading company.  They should have an engineer that can better answer your questions.  Jim