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Sustainable Parking Lot
The goal of this project is to install a landscape around the upper parking lots at The Oregon Garden that will filter pollutants from parking lot run-off and require a minimum of water, fertilizer, and maintenance while providing a beautiful welcome for visitors. The landscape will consist primarily of Mediterranean and other drought-tolerant trees, shrubs, perennials and grasses. Data will be collected on flowering and growth, cold-hardiness, and overall landscape worthiness of the individual species. Following the establishment year, data will be collected to compare these characteristics on non-irrigated versus occasionally irrigated sections of the landscape.
The climate conditions of western Oregon place significant summer drought stress on landscape plants used in the Willamette Valley, with the result that most require irrigation for best performance or even survival. Landscapes installed in parking lots or other streetscapes are often subject to additional stresses because of poor soil conditions and the excess heat load from paved surfaces surrounding them. A typical landscape palette of Rhododendron cultivars, Viburnum davidii, Vinca minor, and others often struggles in these situations. Mediterranean plants, however, are well-adapted to the summer drought and poor soil conditions that we experience in urban Oregon. Plants such as strawberry tree (Arbutus unedo), rockrose (Cistus spp.), California lilac (Ceanothus spp.) and lauristinus (Viburnum tinus) are being grown in Oregon. However, most mediterranean plants are still rare in cultivation here and rarely utilized where they would be best adapted, such as in streetscapes.
Water availability and quality is already an issue in some communities in western Oregon, and water is forecast to become increasingly scarce as Valley communities grow over the next 20 years. Nitrate and phosphorus pollution of water due to fertilizer use is another concern. Landscaping strategies that allow development of attractive, functional plantings that minimize, or eliminate, requirements for supplemental water or fertilizer are in greater demand.
Signage and brochures at the Sustainable Parking Lot landscape will explain the purpose of the research and its methodology. The individual plants will also be labeled.
Principle Investigator: Neil Bell, Marion County Extension, OSU neil.bell@oregonstate.edu in partnership with Cistus Design and Oregon Community Trees
Comments
Sustainable Parking Lot
Would like to get a copy of any interim reports. We are looking at bioswales to capture the 1sr 1/10th inch of runoff from parking lots. Have you looked at the concept of structural soils placed under parking lot pavement, particularly permeable pavements. They are coarse gravels with a small percentage of clay loam added that have a very high voids volume, they allow tree roots to spread out under the parking lot and also store water to allow slow infiltration into tight soils. You can Google structural soils to into.
Max Kroschel,P.E., LACSD
Structural soils etc
Max,
We actually have used structural soil in a different landscape area at The Oregon Garden- the entry courtyard by the Visitors Ctr and Education Building with the cherry trees. We took our research/reference on that from Nina Basik's work at Cornell University, but our Horticulture Director at the time made some modifications in the exact recipe to fit our site and materials available. It seems to be working well.
Unfortunately, that wasn't an option with the parking lots unless we started all over from scratch. By the time the Sustainable Parking Lot Project came along, the conventional paved parking areas were already in place. Looking back, we could have been much more sustainable from the beginning with structural soil and permeable concrete or pavers, but we decided tearing out existing concrete to do these things wasn't sustainable for either our budget or the use of natural resources. So, this project shows what to do with an existing scenario to make it function better for water quality and plant performance. Last year was the establishment year. This year we turn off all irrigation to half of each planting and monitor plant success. There really aren't any interim reports at this time, but please keep directing specific questions to either Neil or myself and we'll feed you our best answers.
Renee Stoops
seeking information and discussion
Dear Mr, Ms Bell,
as a reminder on a earlier send mail. (see below)
I want again to show a big interest in the project initiated by sprout.
I would still want to find out more about this project and other simalar projects that tackle the parking lot as a designated unsustainable place for the car.
Please tell me how this project is doing and if there is a possibility to find more information on this and similar projects.
Thank in advance,
yours truely,
Jip Nelissen
Graduation Student at the Technical university of Architecture in Delft.
previous mail:
Dear Mr, Ms Bell,
I'm currently graduating at the Technical University in Delft at the facultty of architecture.
I'm designing a landscape of allotment gardens on top of an integrated building.
Here I seeking possibilities in green to help me tackle the car and parking areas.
This is why I'm very interested in your project and eager to know more about it.
I hope you can tell me more about.
Thanks in advance,
Jip Nelissen
Reply from Neil Bell
The parking lot project is at the Oregon Garden and was initiated with a grant from SPROUT. It was really an effort to design a planting for a parking lot that would require minimum inputs after planting, specifically water, but also fertilizer and pesticides, in particular herbicides of course, as the major pest problem in such planting is always weeds. By eliminating irrigation, you then require drought-tolerant plants capable of surviving the dry summer here in western Oregon. The climate here is a pseudo-mediterranean one with little or no rain in June-October, and fairly warm summer temperatures with 15-20 days above 30C. Our plant palette then was chosen with this in mind, and an additional requirement was that many of the plant be effective evergreen groundcovers. Over the last few years we have evaluated a number of genera of drought tolerant plants for groundcover, including Ceanothus, Cistus, Halimium, and soon Arctostaphylos and Grevillea. Out of the trials so far, we have selected a number of cultivars which can be grown without summer irrigation and which have a desirable, low, spreading growth habit which make them very effective at suppressing weeds. If we have good groundcover and if we eliminate summer irrigation, weed problems are substantially reduced. Most of these selected plants also thrive in relatively poor soils, reducing the need for fertilizer applications.
So, the basis of the project is appropriate plant selection, it is really quite simple. The term “Sustainable Parking Lot” was actually applied by the SPROUT staff, I prefer “low-input” as a description, myself. I’ve attached a couple of photos of the project so you can see the site prior to landscaping and more recent photos after planting. The site consists of two, long narrow strips which originated with the construction of the parking lot. The soils here are very full of rock-this was a problem for planting. In many situations like this, landscapers would simply drop a sandy “topsoil” typically used around here on top of this rocky soil, and plant into the sand (texturally, this “topsoil” is sand or sometimes loamy sand). We did not want to do that, as besides the rock, the soils are actually quite good quality, if the compaction resulting from construction is eliminated. The two planting strips were roughly graded, and soil samples collected for analysis, but no further work or amendment were done (again, to minimize inputs). The planting was done in May 2007. A plant list is attached. After planting, ½ of each planting strip will be irrigated, the other ½ will not be irrigated. Plant performance in each area is evaluated in late summer, to demonstrate how plant quality varies between irrigated and non-irrigated area.
I hope this answers some of your questions. If you have additional questions, please let me know.
I am happy to find this post
I am happy to find this post very useful for me, as it contains lot of information. I always prefer to read the quality content and this thing I found in you post. Thanks for sharing
Good Idea
Sounds like a very Green project. If it works, it might become a standard for future parking lots.
Great Project
Great project. This is what we need to do in all the parts of the world. We should encourage to make our place greener than now which will omit the problems of drought, less rainfall etc. Such kind of projects has helped to make Oregon the most greenest part of the US. Good Job. This will work as a inspiration to others, nice way to spread the knowledge.
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