Unless some compelling new information comes out at Tuesday evening’s workshop session, it seems clear that Evanston aldermen should opt for asphalt as the material to surface the renovated multi-use path in the Ladd Arboretum.

With asphalt we’ll get a path that can be easily plowed for wintertime use and won’t flood in the summertime.

Therefore it will be usable year-round by pedestrians — including students walking to Kingsley and Haven schools — as well as by bicyclists and wheelchair users.

The altermative recommended by members of the advisory Ladd Arboretum Committee — using crushed stone, as was done a half century ago for the existing paths — provides none of these advantages. And, city staff says, it will require roughly four times as much spending of local tax funds to implement.

It is not acceptable to have the path be inaccessible much of the year, to force kids to take a different route to school or to spend hundreds of thousands of extra dollars simply to cater to the committee members’ aesthetic preference for crushed stone.

The porous concrete solution recommended by city staff as a compromise is no cheaper than the crushed stone. It shares advantages with asphalt in being plowable and unlikely to flood. While it comes closer than asphalt to matching the look of crushed stone, its rougher-than-asphalt surface may prove less pleasant to ride on.

And in an area surrounded mostly by grass, trees and brush, the ability of porous concrete to let water percolate through into the ground seems to be a marginal benefit that doesn’t justify the added cost.

Asphalt is widely used for paths in prominent arboretums around the country — from the Chicago Botanic Garden and the Morton Arboretum here in the Chicago area to the Arnold Arboretum in Boston. It’s the right solution for the Ladd Arboretum as well.

The workshop session about the arboretum path is scheduled for 6 p.m. Tuesday in the Parasol Room at the Civic Center, 2100 Ridge Ave.

Related stories

Aldermen delay vote on rebuilding arboretum path (2/10/15)

Fancy path choice to quadruple local taxpayer cost (2/8/15)

Bill Smith is the editor and publisher of Evanston Now.

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  1. The only safe solution

    When we have a snow over a couple inches the kids that walk to school are pushed out onto McCormick. The pro gravel letter published on this site last week diminished the serious safety concern this creates. The alderman who I do not know anything about is correct when she stated, "kids will take the shortest path between two points." Sure, it would be great if they would hop on the bus or walk another route, but the reality is that for years upon years a small group of kids does not take the safest route. And so paving is the only safe solution.

    Now, the primary argument against paving seems to be global warming impact through emissions which is a real concern. I would suggest making the area around the center including the parking lot no parking except for handicapped. This will mean that people visiting the center will have no way to get there besides biking or walking. I think those concerned with the GWI would embrace this as in time it will offset the emission from the manufacturing of the asphalt.

    1. Arboretum Paths

      I totally disagree with the writers thought process on choosing asphalt, a bio-degradable product full of polycyclic aromatic hydrocarbons that not only poisons the ground it lies on but will also come with a much higher lifetime cost due to regular maintenance needs. It is for these reasons and more that the National Arboretum in Washington, DC has chosen to go with pervious concrete although probably not what the writer has seen before. I am active in the pervious concrete industry and have been for twenty five years now. Our company consults on projects around the country and world and we always promote a 1/4" stone pervious mix versus the industry standard 3/8" mix. The reasons we choose a smaller stone is aesthetics, it simply looks better, it is able to be walked on in bare feet and there is 65% less maintenance than that of a larger stone. Before we (mankind) paved over Paradise with asphalt and concrete and it rained, it went back into the ground, where it belongs. The use of pervious concrete returns balance to Mother Nature.

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