Yesterday someone pointed out to me a problem with counting parkland purchases as mitigation for road impacts that I hadn't thought of before: the Habitat Plan treats the amount of road impacts as a fixed quantity (somewhat simplified but accurate enough for these purposes), when in fact it could be higher or lower. If the County Roads Department uses parkland to count as mitigation for road impacts rather than paying for it from the Roads budget, it has just lost any incentive it has to minimize the impacts. In other words, we'll get far more impacts than would otherwise be the case. True, those impacts will be mitigated, but that's inadequate for two reasons: first, mitigation isn't as good as avoiding impacts, and second, the mitigation has the effect of eliminating a net benefit of more endangered habitat.
Let's walk through two cost scenarios as an example, where the County Roads Department has to choose between widening a road into endangered habitat riparian zone on one side, or encroaching into a hillside on the other:
Scenario 1: Costs of widening a road into riparian zone:
Construction and non-habitat costs: $1.0 million
Habitat mitigation cost: $0.5 million
Total: $1.5 million
Scenario 2: Costs of widening a road into a hillside:
Construction and non-habitat costs: $1.1 million
Habitat mitigation cost: none
Total: $1.1 million
The rational choice if the Roads Department considered (meaning, "had to pay for") all costs would be Scenario 2. But if the Roads Department just gets free credit for land purchased by the Parks Department, then Scenario 2 looks more expensive to it, and it will choose Scenario 1 instead. I was fumbling toward this idea when I repeatedly told the County that it's bad policy to shift costs between departments, but this points it out really well.
So what's the likely County response? If I were them, I'd point to toothless and unenforceable provisions in the Habitat Plan that say "where economically feasible, impacts should be avoided" and claim that meant something. I expect they believe that to be true in the abstract, but when it gets down to the specifics of each budget, the real choice will always default to Scenario 1.
(More reasons here for why using Parks Charter Fund is a bad idea.)