Future begins today. And it is our point how to make it better. We don’t want future full of inevitable destruction of world parts. And we have to take care about right now. People must be responsible for their actions, thoughts and mistakes; help the developing world skip over more than a century of polluting and industrialization that the society created (McLennan, 2004, p. 247). So we must provide architecture with some special design that will help us to keep the world less polluted. So future is in sustainable architecture.
LID is the way to improve or redevelop city landscape considering environment, using stormwater for irrigation. LID is pointed on preservation and restoration of natural features, reducing effective imperviousness to create a functional and attractive drainage of a site, using stormwater as necessary resource, instead of wasting it. When commonly used, LID can support or restore hydrological and ecological functions of watercourse. Water Environment Research Foundation and others proved that LID is the most efficient practice (EPA, 2010).
Concerning the given site, let me offer some ideas of how to renovate it using some special sustainable techniques. As the mixed-use center is surrounded with many parking-places, it would be reasonable to provide these parking lots with flexible base porous pavement. That is sufficient as pavement cracks under the external factors such as snowy winter when it snows heavily and pavement is freezing and thawing what accelerate the weakening in subbase, and following warm spring when snow melts fast, and water seeps through the surface course weakening the base (Dawson, 2009, p. 47). Beside that, sun and heat also do no good for pavement, accelerating the process of deterioration. “Porous pavements have been demonstrated as effective means in managing runoff from paved surfaces” (Brattebo, 2003, p. 4369).
Porous pavement is one of the best and the most effective ways to support green, viable growth. Advantages of porous pavement for parking lots is in the fact that the water reservoir settled under the pavement, absorbs all precipitations dropped on surface, and it considerably decreases land surface used for a drainage and irrigation systems (EPA, 2000). “Porous pavement increases groundwater recharge, reduces pollutants in stormwater runoff, and helps alleviate flooding and contamination to streams” (EPS, 2010).
On the roof of the mixed-used center should be placed green-roof. That would reduce heating and cooling, filter stormwater from polluters, etc. It will absorb rainwater, provide insulation and help to lower urban temperatures – it is rather sufficient for the town centers. Green roofs added to all buildings can have a dramatic effect on maximum surface temperatures, keeping temperature lower in places where the building proportion is high and the evaporative fraction is low (Gill, 2010, p. 122). Drainage and watering should be provided with piped system which gathers stormwaters into special reservoirs and filter through green-roof network. Roof garden is necessary to clear the air from polluters. Concerning necessary plants, it would be suitable to plant there turf grass, succulents or any other ground-covering plant.
It would be useful to provide the center with rain harvesting system, as collected water can be used for irrigation and other needs. First of all, it is necessary to put pipes with funnels on perimeter of the center. Pipe ends must be put into barrel where it would be kept. Besides, ground area on perimeter of parking lots and the center also should be provided with side ditches to collect water.
Also it is necessary to provide bioretention system around the center and the parking lots. This treatment area will collect stormwater runoffs to remove contaminants and sedimentation. This area should consist of several layers, such as a sand layer which is necessary for runoff velocity, the ponding area where water will gather, and a mulch protective layer for a repeated filtration, and also a grass layer for soil drainage. The mulch layer also filters polluting substances, providing environment for growth of microorganisms which, when rotting, form oil materials and others organic substances. This layer is similar to layer made of the fallen leaves in wood which prevents erosion and soil drying.
The grass cover also reduces probability of erosion, even better, than mulch. “The maximum sheet flow velocity prior to erosive conditions is 1 foot per second for planted ground cover and 3 feet per second)for mulch” (Clar, 2004). Bioretention units around parking lots will serve to filter pollutants from the water. There should be inserted a lot of such units as patrol cars, dust, acid rain and other pollutants subside onto the ground and pavement. Units around center site will serve to re-filter the stormwater gathered by rain harvesting system.
Storage of rain water is provided also with emptiness in soil. The collected water and nutrients in this case become plants more accessible to processing. The arrangement of bioretention area is defined by site borders, for example types of soil which can be found on the given site, local vegetation and drainage system. Sites with clay sandstone are most of all intended for bioretention, as it can be taken and used as drainage system that saves money and time for purchase of soil of this kind.
“An unstable surrounding soil stratum and soils with clay content greater than 25 percent may preclude the use of bioretention, as would a site with slopes greater than 20 percent or a site with mature trees that would be removed during construction of the best management practices” (Largo, MD, 2002). Also that will be decorated with some plants such as trees and bushes to make it look more attractive.
All green areas of the site must be provided with net of drip irrigation. It should be performed as small drippers and net of invisible outlets for drip lines and micro pipes. This net will constantly water the area nearby with water drops. It will minimize water expenses and soil will never be drained.
Beside ecological benefits, it will bring also financial benefits as creating such a reservoir for gathering stormwaters and providing drip irrigation system using this water will save money spent on water. It will give the opportunity to allow it to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone. (Jain Irrigation, 2006).
If all these measures will be taken, it will bring many benefits to the center. The first is rather obvious. This will add to the attractiveness of the center. Many trees, grass and flowers will create a kind of recreational area which is sure to take attention of lots of people. Thus making the second benefit – financial profit. It will save costs spent on buying extra water for irrigation, for repairing roof, its winterization, etc. And the third is preserving our ecology a little bit less polluted.
Reference List
Brattebo, B. O., and Booth, D. B. (2003). Long-Term Stormwater Quantity and Quality Performance of Permeable Pavement Systems.
Clar, M. L., Barfield, B. J., & O’Connor, T. P. (2004). Stormwater Best Management Practice Design Guide (Vol. 2): Vegetative Biofilters.
Cincinnati: United States Department of Environmental Protection Agency.
Dawson, Andrew. 2009. Water in Road Structures. Springer: Netherlands.
Environmental Planning Section. Porous Pavement. (2010). Web.
EPA. (2000). Field Evaluation of Permeable Pavements for Stormwater Management. Washington D. C.: EPA.
Gill, S.E., J.F. Handley, A.R. Ennos and S. Pauleit. Adapting Cities for climate Change: The Role of the Green Infrastructure. Built Environment (Vol 33).
Jain Irrigation. (2006). Maintenance Manual.
Jason F. McLennan. (2004). The Philosophy of Sustainable Design: the Future of Architecture. Canada.
Prince George’s County Department of Environmental Resources. Largo, MD. (2002). Bioretention Manual. US Environmental Protection Agency. Low Impact Development (LID). Web.