Water

The DNR are setting up three groundwater management areas in the state to study problems of our aquifers being drawn down to critically low levels. They presented their plan for this at a meeting on Wed.

Interestingly, though not too surprisingly, these issues dovetail quite closely with topics on both Streets.MN and Strongtowns.

The bulk of the meeting was Government Pablum—DNR folks taking considerable time to state the obvious. In their defense, there are only so many ways you can say that we have a problem and want to find a solution, while avoiding any detail or admission that they should likely have done something long before now[1].

The discussion at the end was quite a bit more valuable.

At the top of the list of issues is that we appear to be using too much groundwater and our use is increasing.

WaterUse

Graphic: MN DNR

The big easy target here is ornamental irrigation. Large lawns, commercial and residential, with few shade trees gulp down huge amounts of water to stay rainforest green in the Minnesota tundra. Worse, as much as 50% of this is wasted by those watering too much, during the heat of the day, when it’s raining or windy, and having improperly adjusted heads that spray water in the air or in the street instead of along the ground.

Agricultural irrigation, largely due to huge increases in corn and soybeans, is also an increasing problem though may not have as easy a solution.

The number two ‘wasted use’ according to one DNR speaker is polluted aquifers. He seemingly indicated that about 10% of our sources are no longer useable, primarily due to dangerous levels of nitrates from agricultural and ornamental fertilizers. Pollution from automobiles and other sources are also beginning to make it down to our aquifers and are expected to become a larger problem. In particular, run-off from gas stations is a significant concern.

Other residential and industrial uses of water are also targets for reduced consumption though these were not discussed at much length.

An issue was raised about Minnesota being behind most other states with regard to water conservation efforts, particularly uses of grey water (for example, using water from showers to flush toilets). Several city officials noted that our state plumbing code is a significant hinderance in this area.

Water system leakage was also discussed with Rochester pronounced the best in the state with only about 5% annual loss while many others are closer to 20% or more. This though was tempered with a note that most system leakage likely does flow back to the aquifers.

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On the other end we have an infiltration and recharge problem. Water that would normally percolate down to the aquifers to recharge them is instead flowing to storm sewers and then flushed down the Mississippi.

The seemingly obvious issues here are too much non-permeable surface area in pavement and buildings, not enough separation between these areas, and poor management of permeable areas.

The DNR’s official stance, as with water uses above, is that these are areas that need to be studied and they’d prefer to provide only high level guidance to cities and others rather than any specific dictums.

Possible solutions discussed among attendees come in several areas.

Number one is to reduce paved surface area—reducing street widths and the number and size of parking lots[2]. Two problems raised with street widths were fire chiefs and traffic engineers.

The fire chiefs say that this will prevent them from getting to emergencies. The question these same fire chiefs don’t seem to like is why they don’t use narrower trucks (or apparatus as they prefer to call their trucks) like those used outside the U.S.

From U.S. traffic engineers comes the belief that wider streets, both lanes and shoulders, are safer and they have been very reluctant to change this belief. Fortunately this does seem to be changing.

Another option, Shoreview has a test street that is permeable and with no storm sewers that would seem to abrogate some of the problems. I did not get a chance to talk to anyone from Shoreview about how well this is working. From comments though it appears to work well, at least from a not flooding standpoint which would tend to indicate that it is functioning well as a permeable surface. One question is if it does anything to reduce pollution flowing to the aquifers (not likely) and one known issue is cost.

Likely a combination of narrower streets, smaller parking lots, and some portion of each utilizing permeable pavement will be needed. While we can likely reduce many parking lots by [10-20% immediately with little to no impact], encouraging more walking and bicycling may provide much more significant opportunities and should also lessen the issues of pollution impacting aquifers.

Next on was the surface area consumed by buildings with one seemingly obvious solution being a move towards more mixed use structures.

In the north and east suburbs, like most, we have an abundance of single story strip malls, big-box stores, and other one or two story buildings spread out across large swaths of otherwise permeable land. These are often directly next to two and three story apartment, condo, and office buildings. Combining these should not only result in significantly reducing the footprint required of the buildings themselves, but also of the surrounding paved parking surface since some could be shared between workers and shoppers during the day and residents during the night.

Almost across the board the solutions to our water problems seem the same as the solutions to the problems discussed here and on Strongtowns.org. Sometimes the weight of a solution becomes too great for even politicians to ignore.


[1] Lay persons view. Perhaps there wasn’t much they could have done sooner to avoid this.

[2] A related issue that I’ve wondered about is the extent to which snow and rain that fall on permeable surfaces such as lawns, end up running off to streets and storm sewers due to landscape contours designed to do exactly this. In my neighborhood each spring, for weeks after the streets are completely dry, there continues a rush of water in to the storm sewers from snow melt. The same happens when people water their lawns including those with properly adjusted sprinkler heads that do not hit the street. My assumption is that if it happens with sprinklers, that a significant amount of the rain that hits our yards is also washing down the sewer and, compliments of the Met Council, down the Mississippi.


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5 Responses to Water

  1. Nathaniel M Hood
    Nathaniel January 11, 2014 at 9:46 am #

    Water is a serious issue, often overlooked in urbanist circles. Excellent article. I had to shake my head at your comment about sprinkler systems just shooting water onto the street. I have two neighbors who have had this very issue for 2 years (haven’t fixed it). It absolutely boggles my mind. Anyway – good piece!

    • Walker January 13, 2014 at 3:32 pm #

      Thank you. Kind of a quickie, but some interesting stuff from the meeting.

  2. Joseph Totten
    Joseph Totten January 11, 2014 at 1:49 pm #

    The City of Minneapolis had parking bays along 50th Street near Penn Ave that were made of porous concrete, they’re being torn out (may have been done already) because the turning motions of parallel parking completely reduced the concrete to just gravel.

    • Walker January 13, 2014 at 3:30 pm #

      Joseph, thanks for posting that. Do you know if this is a problem with all permeable pavement or this one or some in particular?

  3. Stacy January 14, 2014 at 3:20 pm #

    Porous pavements are shown to reduce pollutants. That is why they can substitute for storm water retention features. According to Public Works Magazine:

    “[permeable pavements are] approved by the U.S. Environmental Protection Agency as a best management practice, and has been proven to reduce the rate of runoff and levels of associated pollutants in addition to increasing the ground water recharge rate.”

    MnDOT has been doing some testing with permeable pavements on the MnROAD pavement test track. Initially, it held up to the freeze-thaw conditions better than expected, but they don’t have complete results, yet.