Fig. 4.

Costs of barrier removal relative to funding levels under various spatial and temporal allocation scenarios. (A) For dam removal, the frequency histogram of project costs is compared with per-county budgets under four scenarios: $100 million total budget allocated among counties as a series of 10 annual investments (a 10 × 10% trickle approach), $300 million trickle, $100 million allocated as a single pulse, and $300 million pulse. Vertical line position on the horizontal axis marks the funding available to each county under each of the four scenarios. (B) For road crossings, retrofitting costs are compared with the same four budget scenarios.