If you wanted to design a property rights regime that guaranteed the waste of a scarce resource, you could hardly do better than Western water law's doctrine of prior appropriation. It requires rights holders to put water to "beneficial use" or—after five consecutive years of non-use—forfeit the right. [1] The result is a textbook perverse incentive: a farmer who irrigates more efficiently risks losing the conserved portion of her right, so the private return to conservation is negative even when the social return is big.
Oregon tried to eliminate the perverse incentive with its 1987 Instream Water Right Act that made instream flow a beneficial use. [2] On the Deschutes, conservancies now lease and buy water for the river. [3], but legalizing the trade didn't create a liquid market. Rights are mostly held by irrigation districts rather than individual farmers, so every deal needs board approval, and transaction costs run high: quantifying how much water actually reaches crops through leaky, century-old canals is expensive, and farmers still fear that proving they can conserve invites a future challenge to their right.
In the Colorado River, states face the same problem. If an Upper Basin state conserves, the saved water flows downstream to be consumed by someone else which creates the risk of becoming the baseline for future cuts. [4] Instead, the feds pay farmers billions to fallow fields—a costly government subsidy trying to address the perverse consequences of another government policy. [5]
BOTTOM LINE: any rule tying an asset's ownership to its continuous consumption—budget lines that vanish if unspent, headcount that shrinks if unfilled—will be consumed regardless of value.
NOTES
[1] Schwabe, Williamson & Wyatt, "Oregon Water Law Questions and Answers" — beneficial use requirement and five-year forfeiture rule. https://www.schwabe.com/publication/oregon-water-law-questions-and-answers/
[2] Oregon Legislature, "Background Brief on Water Rights" — the 1987 legislation adding instream water rights as a beneficial use. https://www.oregonlegislature.gov/lpro/Publications/2004HM_Water_Rights.pdf
[3] University of Oregon School of Law, "Evaluating Instream Flow Programs" — Oregon's 1,100+ instream leases and transfers, including the Deschutes River Conservancy's role. https://law.uoregon.edu/sites/default/files/ai61_ch._22_with_legend1.pdf
[4] High Country News, "Why Colorado River negotiations are so difficult" — prior appropriation dynamics and the interstate stalemate. https://www.hcn.org/articles/why-colorado-river-negotiations-are-so-difficult/
[5] Congressional Research Service, "Management of the Colorado River" (R45546) — federally compensated conservation, including 2.3 million acre-feet paid for with congressionally approved drought funds. https://www.congress.gov/crs-product/R45546
HT: Claude Fable