The followng proposal was written听by Kira Forbes, CU 麻豆官网 undergraduate student in environmental design/environmental products of design, on behalf of CEDaR.
The alley and neighboring plots of land behind AutoZone Auto Parts off of Colfax Avenue and Cherry Street in Denver, Colorado are prone to heavy water traffic and flooding.
Especially during the spring and early summer, the听area fills听with runoff from an听adjacent parking lot and busy highway. The corresponding runoff is contaminated from听oil and gas toxins from听AutoZone's parking lot听and debris from the constant traffic along Colfax Avenue. Because a community vegetable garden is behind the alley, there was concern regarding the way the water moves and distributes.
After Forbes conducted听research and collected data, she听proposed the following design solution:
鈼� Regrade the plot of land between the metal fence and paved alleyway.
鈼� Relocate and plant new vegetation.
鈼� Add planter boxes to the wooden fence that separates听the residential housing and commercial businesses.
The manipulation of topography was based on an earlier design intervention. Several听years ago on the far south end of the lot next to the wooden fence, a small bioswale helped collect the water immediately running northbound from the parking lot.
This was the basis for the next design iteration. Although the bioswale听was just a small dugout, it appeared to be doing its intended job. Therefore, I听proposed to expand this concept to the entire east side of the property between the metal fence and the pavement.
Currently, there is a timber boundary line approximately three听feet听offset from the alleyway. To maximize the space, the new boundary would extend to the end of the alley. The regrading slope would be 4:1 as recommended by National Association of City Transportation officials, and potentially could be steeper with a slope ration of 3:1. Expanding the bioswale concept would听help collect more water in a specific area as opposed to running through the rest of the property and down the alleyway to the neighborhood street.
Instead of completely changing the existing site, I听proposed to relocate and replant some of the current shrubs along the perimeter of the new boundary. Since the shrubs听are fairly mature plants, they are already acclimated to the specific environment. These plants will also provide screening along the property line to add more privacy from the alleyway. In addition to the existing plants, new plants will be introduced to the site. Having a wider variety of plants will provide greater visual intrigue, help filtrate water听and attract native pollinators, which also will be beneficial to听the community garden.
A view of the alley before it was improved.
The proposed听plants are native to Colorado, drought-tolerant and have听a greater bloom range throughout the year. They听include Panicum virgatum (Heavy Metal Switchgrass), Schizachyrium scoparium (Little Bluestem), and Monarda fistulosa (Rocky Mountain Bee Balm).
Furthermore, the planter boxes will serve two primary functions. First, they will help funnel the runoff from the street and parking lot into the designated area. The boxes would be insulated with a waterproof lining to protect the wooden structure from deteriorating quickly. Secondly, the boxes would act as actual planter boxes for either food (herbs) or additional flowers to help beautify the alleyway. The boxes would be designed with听separated drainage systems so听if the community wanted to use these boxes for growing food, the boxes听would not become听contaminated by runoff.
Student helpers:听Elizabeth听Stagnaro, CEDaR undergraduate employee and Andrew Smith.
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Associated Researchers
