Controlled drainage uses stoplogs or flashboards to dam outflowing drained water, resulting in a rising water table which keeps the soil appropriately saturated, improves yields (26-60bu/ac), decreases expenditures on fertilizers (~30%) and decreases dependency on inefficient irrigation techniques during periods of limited rainfall.
Most likely. A drainage professional can assess your system and develop a plan to retrofit a controlled drainage structure, even if you have clay in the ground.
Yes. Programs from NRCS (554 and 587) EQIP, CSP, CRP and CREP all may provide assistance with the initial costs of installation and equipment.
Typically, 10-20 acres can be adequately controlled with one management structure like the Agri-Drain.