Water for our future

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Streets.mn has me on assignment in mostly sunnier San Diego, and besides seeing a lot of cool animals, this trip has me thinking about water (ok, not on assignment, but on vacation). San Diego is classified as semi-arid to arid, receiving less than 12 inches of rain per year. Typical suburban yards look a lot less grassy and lot more cactusy. You see things like this and like this, which you don’t typically see in the midwest. Surface water from rainfall runoff hasn’t been able to meet the region’s water supply needs since 1947. Because of this, the County of San Diego imports 80 percent of its water from sources hundreds of miles away. Many parts of California continue to grapple with water supply issues.

What does all this have to do with Minnesota? We have tons of water, right? Well, on the surface yes, but we’re using our groundwater much faster than it’s being replaced, and that’s a problem. That was one of the main topics at a Thrive MSP 2040 Roundtable discussion I attended a number of weeks ago, and have been meaning to post about since. The 7-county region now gets 70 percent of our water from groundwater sources, up from 15 percent in the 50′s. In some places this means we’re reducing groundwater levels by over a foot a year. These conditions led the Star Tribune to produce these troubling graphics recently.

Under a future scenario with continued population growth and no change in water supply practices, many areas, particularly in the east metro, will face serious water supply problems. The case of White Bear Lake is a troubling example of what can happen when groundwater supplies become overused. In other locations, reductions in groundwater could mean cities and homeowners having wells run dry, and more lakes, streams and wetlands becoming damaged. Minnesotans tend to cherish water of all kinds, making these kinds of trends particularly troubling. For a good overview of the issue, watch this video from the Met Council.

The good news is, there are solutions, all of which are easier than building a huge pipe to a river hundreds of miles away, like the one our California friends are stuck with. Some of the approaches discussed at the roundtable meeting were:

  • Conservation. The Twin Cities isn’t a water starved region like the southwest. We actually haven’t done a lot to encourage people to conserve water. There aren’t regular watering bans, municipal water is very cheap, and conservation technologies are just catching on here.
  • Infilltration/re-infilltration. Surprising to me, daily groundwater withdrawal for municipal use is about equal to what we flush down the drain, eventually sending it to regional treatment facilities and down the Mississippi. What if we were able to send some of that treated wastewater back into the aquifer? Water supply planners at the meeting said that this treated water is generally clean enough, but some work would have to be done to figure out how to best get it into the ground and where exactly it’s needed most.
  • Protecting infilltration areas. You may have been reading this post and thinking, “what does this have to do with land use and transportation?” Well, thanks for hanging in this long. In turns out that certain parts of our region are “recharge” areas where groundwater can quickly move from the surface into the aquifer. If these areas become more developed and covered with impervious and semi-impervious surface like parking lots and suburban lawns, less water will make it to the aquifer. The update of the regional plan may restrict certain areas from development to protect these recharge areas or suggest development practices that allow water to infilltrate on-site.
  • Build new pipes. According to water supply planners, we’ve got plenty of water in one source: the Mississippi River. Facing serious water supply problems, some communities may need to build new infrastructure such as pipes or treatment facilities to access river water. Adjacent cities could also connect to the Minneapolis and Saint Paul water supply system, which both use river water. This could mean some loss of independence in some communities that have historically depended on their own wells, and possibly some large infrastructure costs.