Who should pay for irrigation modernization?

I’ve written about this many times, but a recent OPB article illustrated it once again: real farmers can pay.  “Eastern Oregon group looks toward Columbia River to solve groundwater problems” is about farmers replacing groundwater with water from the Columbia River for irrigating their crops.  I’m not informed enough to have a position on that and we certainly have experience with excessive surface water withdrawals destroying rivers around here.  What struck me is that these farmers understand the need to stabilize and recharge aquifers, are looking to new water sources, and are paying most of the costs of switching “with less than 10% coming from government coffers”.  I like that math.  Other states have required farmers to upgrade their irrigation systems and pay the cost.  Why can’t we do this in Central Oregon?  Why are taxpayers shouldering the cost for modernization efforts?  If an irrigator has an economically productive farm they should have a business model that includes the cost of production along with its upgrade and maintenance.  Of course, hobby farmers they should pay for their hobby.  This seems like Economics 101 to me.