Created on Thursday, 02 August 2007 06:35
Last Updated on Thursday, 02 August 2007 06:35
By Ben Falk and Mike Blazewicz
As design and planning professionals working in this Valley for a number of years we'd like to offer a few clarifications of -- and potential solutions to -- the Carroll Road stormwater runoff issue discussed in recent issues of <MI>The Valley Reporter<D>. This issue represents a unique opportunity for this Valley to implement innovative solutions to the pollution of our river.
Clarifications of the situation on Carroll Road:
• Polluted stormwater is received by the Carroll Road Pond from a much larger area than the Big Picture Theater's parking lot. The theater just happens to be the property adjacent to the pond. Polluted stormwater enters the pond directly from the parking lot in front of the Big Picture Theater, from at least part of Wood and Wood's parking lot and likely from many impervious surfaces uphill from these parcels, as well as from Carroll Road itself. Of course, a much larger volume of polluted runoff enters the pond indirectly from the impervious surfaces further upstream owned by Shaw's, TD Banknorth, and numerous other parcels.
• The recent grading work at issue at the theater has simply exposed a pre-existing pollution problem. Instead of polluted runoff flowing into the pond in a less visible location, some of it now flows into the pond in front of the theater.
• Piping polluted runoff or sending it underground may hide the problem temporarily, but it is no solution. The source of this kind of polluted runoff entering our river is two-fold. Primarily, it is a result of impervious or relatively impervious surfaces (dirt or paved parking lots and roads, rooftops, work yards, many lawns and agricultural fields, etc.) that provide a source of contaminants (silt, lubricants, gas, diesel, pesticides, nitrogen/phosphorous from septic systems and fertilizers, etc.) to water runoff during rain or snow melting events. Secondarily, it is a failure to remove these contaminants from surface water before it enters the river (or lake, groundwater aquifer, etc.)
Solving our Valley's pollution problem at the Carroll Road Pond is most likely if this situation is recognized as one symptom in the bigger picture of non point-source pollution in the watershed. Fortunately innovative solutions to such challenges are being implemented all over the world -- and they don't require ripping out all of our parking lots and roadways in the process. Such strategies can save our towns money in both the short- and long-term while increasing the quality of our common resources like the river. The following are practical steps that planners and developers in this Valley can take to ensure a reduction in the pollution of our precious fresh water.
• Make parking lots only as big as they need to be. For example, design them for typical use -- not maximum use, and take advantage of parallel parking on roadways and other overflow parking strategies. Is the parking lot on Carroll Road bigger than it needs to be? Most of the time this lot is mostly empty. There are many possibilities for overflow parking in this area. Conversely, if reducing the size of this lot is not desirable, many other strategies such as those below can be implemented here.
• Employ bioswales that retain runoff, filter it, and allow it to seep into the ground or evaporate, instead of drainage ditches that convey water rapidly into the nearest creek or river. See below for more on bioswales.
• Grow trees and other perennials along with, or in place of, lawn and within depressions in parking lots and other impervious areas. Count the amount of land in this valley that is in lawn that doesn't need to be. Take a walk from the Waitsfield Post Office to the Big Picture Theater if you want to experience this firsthand. Lawn has become the default setting for land at high cost in maintenance and pollution. Sensibly, some town commons used to be a combination of fruit trees, nut trees and grazed grass. Strategic mowing abatement is one of the single most cost-effective and practical strategies we can do to enhance the quality of our ecosystems and lives. Meadows and old fields retain and filter water many times faster than turf, and they can be much cheaper to maintain, support wildlife, build soil fertility, absorb carbon dioxide and produce valuable crops.
• Grow cover crops on agricultural land between other cropping rotations (kudos to the many Valley farmers who are instituting such measures).
• Strategically remove curbs along roadsides and parking lots to allow water to sheet into areas of bio-treatment and groundwater recharge rather than concentrate it into storm drains.
Employing bioswales within the Carroll Road parking lot in place of typical drainage ditches is a particularly timely approach for this site. The functions of these systems are straightforward: retain stormwater, filter it with plants, infiltrate it into the ground and let the plants evapotranspirate it. The design is straightforward: Whereas a typical drainage ditch is a bare, stoned, or grassed watercourse across a slope, a bioswale is a depression along a slope that is filled with an array of water-loving perennial plants. A bioswale is essentially a mini constructed wetland performing the same valuable functions of a wetland while reducing the negative impact of polluted stormwater runoff.
Besides being used to treat runoff in the location at issue, they can also be used within the parking lot itself by creating depressions instead of mounds between clusters of parking spaces. It's also not difficult to imagine the variety of funding sources available for such durable approaches to stormwater management. The Mad River Valley is in a position to choose to be a leader in watershed protection and town planning. Conversely, our Valley could fall behind as other communities the world over realize the effectiveness of ecologically integrated town planning and implement comprehensive instead of Band-aid solutions in their landscapes.
Ben Falk is site developer and landscape planner and Michael Blazewicz, water quality consultant and former director, Friends of the Mad River.