Undoubtedly, this is an analysis that must be taken into account, since very expensive conservation solutions tend to have little viability. On the other hand, cheap but technically inefficient solutions are also not relevant.

Yes I think a cost benefit analysis is priority as it maximizes on efficiency (use of little to get more) and effectiveness (meeting the set objective) and ultimately, optimal value for soil-water conservation investments.

Cost benefit can be helpful, but many of the conservation measures may not be fully realized for many years. I think I uploaded a gully control cost benefit using the DISCOUNT program in basic (ok, this was in the 1980s). Many conservation efforts years back required cost benefit ratios, but it was a challenge to develop the non-market values associated with some benefits. One benefit that converting gullied land to pine forest besides less sediment and improved water is reduced flooding. And converting the poor gullied land back to forest has commercial value for habitat improvement, thinning and harvest, which I included. Back then carbon sequestration was not a topic, but growing forests for lumber and other uses might be considered as beneficial. When I look back in time, we were able to make conservation improvements at lower cost than today, but everything else costs more today, and now more than ever, high quality water and stable ecosystems have values that are increasingly recognized.

Perhaps a reversal might be, what are the costs and loss in value of land and resources if you don’t implement SWCPs (BMPs). Conservation practices can be reasonable in cost if implemented prior to damage. A few of my researchgate entries mention or discuss SWCPs. Some involve only minor training to managers, contractors, land owners, etc. The cost of installing a road the right way, may cost a bit more, and the bad effects and repairs are greatly reduced from a poor road.