How to determine water problems in agricutural fields?

My company is involved in many nature conservation projects. In most occasions obtaining higher groundwater levels is one of the goals in these nature areas. The problem we are dealing with is that agricultural fields around the nature areas might suffer from rising groundwater tables as well (less crop growth, fields are too wet to drive on with heavy machinery etcetera). In that case the farmers can receive a compensation. The challenge however is: how to determine that groundwater tables have (or have not) risen in the agricultural fields? Farmers might claim that their fields are too wet and they apply for compensation, but the wetness can be due to high rainfall or so. Usually historical groundwater data are not available for specific locations so that we have to rely on farmers' experiences...

Models have proven not to be the "silver bullet", because our experience is that they are not always correct due to the smalle scale of the projects. Moreover sometimes the outcome from a groundwater model is that no water problems are expected in the agricultural fields, but farmers claim that they do have problems. How to Judge who is right and whether farmers can receive a compensation?


Any of your ideas is welcome, and if you need more information about the issue, just let me know!