Collapse_ How Societies Choose to Fail or Succeed - Jared Diamond [32]
The Bitterroot’s other water supply besides snowmelt-fed irrigation consists of wells for domestic water use, tapping into underground aquifers. They, too, face the problem of increasing demand for decreasing water. While mountain snowpack and underground aquifers may seem to be separate, they are in fact coupled: some runoff of used irrigation water may percolate down through the ground to the aquifers, and some aquifer water may originate ultimately from snowmelt. Hence the ongoing decrease in Montana’s snowpack forebodes a decrease in the aquifers as well.
There is no doubt about increasing demand for aquifer water: the Bitterroot’s continuing population explosion means more people drinking more water and flushing more toilets. Roxa French, coordinator for the local Bitter Root Water Forum, advises people building new houses to drill their wells deep, because there are going to be “more straws in the milkshake”—i.e., more wells drilled into the same aquifer and lowering its level. Montana law and county regulations about domestic water are currently weak. The well that one new house-owner drills may lower the water level of a neighbor’s well, but it is difficult for the latter person to collect damages. In order to calculate how much domestic water use an aquifer could support, one would have to map the aquifer and to measure how rapidly water is flowing into it, but—astonishingly—those two elementary steps have not been accomplished for any Bitterroot Valley aquifer. The county itself lacks the resources to monitor its aquifers and does not carry out independent assessments of water availability when it is considering a developer’s application to build a new house. Instead, the county relies on the developer’s assurance that enough well water will be available for the house.
Everything that I have said about water so far concerns water quantity. However, there are also issues of water quality, which rivals western Montana’s scenery as its most valuable natural resource because the rivers and irrigation systems originate from relatively pure snowmelt. Despite that advantage, the Bitterroot River is already on Montana’s list of “impaired streams,” for several reasons. The most important of those reasons is buildup of sediments released by erosion, road construction, forest fires, logging, and falling water levels in ditches and streams due to use for irrigation. Most of the Bitterroot’s watersheds are now already eroded or at risk. A second problem is fertilizer runoff: every farmer growing hay adds at least 200 pounds of fertilizer to each acre of land, but it is unknown how much of that fertilizer ends up in the river. Waste nutrients from septic tanks are yet another increasing hazard to water quality. Finally, as I already explained, toxic minerals draining out of mines are the most serious water quality problem in some other parts of Montana, though not in the Bitterroot.
Air quality also deserves brief mention. It may at first seem shameless for me, as a resident of the American city (Los Angeles) with the worst air quality, to say anything negative about Montana in this regard. In fact, some areas of Montana do suffer seasonally from poor air quality, worst of all in Missoula, whose air (despite improvements since the 1980s) is sometimes as bad as in Los Angeles. Missoula’s air problems, exacerbated by winter temperature inversions and by its location in a valley that traps air, stem from a combination of vehicle emissions throughout the year, wood-burning stoves in the winter, and forest fires and logging in the summer.
Montana’s remaining major sets of environmental problems are the linked ones of introductions of harmful non-native species and losses of valuable native species. These problems especially involve fish, deer and elk, and weeds.
Montana originally supported valuable fisheries based on native Cutthroat Trout (Montana