Section 8:  Example Sites

Presented in this Section are 2 example sites:

WestTown - Residential neighborhood - Actual remediation in progress

  Altgeld Gardens - Playground
 
 

WestTown Phytoremediation Project
 
 

The case study for the implementation of the decision tree model a urban community in Chicago, IL called "West Town."

The three main land uses in the West Town community are:

the parkway, which is the strip of land between the sidewalk and the street

the front yard

the backyard at various residences in the area

Each of these areas presents a different challenge in addressing the requirements of phytoremediation.
 

The front and backyards of these residences are used as play areas and sometimes gardens. Since these areas are not mutually exclusive at West Town, there may be some overlap between descriptions for the various land uses.

 Parkway

The parkway is approximately twenty-five feet long and around five to ten feet wide. This area is found between the roadway and the sidewalk in front of the house. These areas are owned and maintained by the City of Chicago. Besides the grass on the parkway, there also may be a few trees planted there. The grass on some sections of the parkway can be classified as sparse at best.

Salinity will be high near the parkway, because salt is deposited from the salting of roadways and sidewalks during the winter. Debris is also a concern because the parkway is in close proximity to the roadways. Grub damage is also a significant problem at some residences in the West Town community. There are several patches of missing grass that have resulted from grub damage at the site. Specific eradication measures, like spiked lawn shoes, may be necessary to ensure that such damage will not occur if new grass is planted on the parkway.

Ideally, the whole lawn should be planted with a grass that has been utilized in phytoremediation. There is the possibility of utilizing grass seed mixtures that will allow for proper growth of the targeted grass, full coverage, as well as demonstrating aesthetic appeal. If phytoremediation can not be achieved, then complete coverage should become the priority. There may be significant difficulties with growing grass on the parkways, as there may be the need for overall changes in many of the soil characteristics to facilitate growth of grasses. Furthermore, the grass will need to be tolerant to debris, road salt, and exhaust fumes stemming from traffic on the adjacent roadways.

General Front Yard

The main component of the front area of West Town homes is an area that is termed as the "general front yard" (GFY). The general front yard has the approximate dimensions of five feet by ten feet at most homes. These areas are usually gated and have limited access, and are rarely covered in grass. The predominant use of the general front yard areas is for flower gardens and for shrubs. Since these areas are gated off, there is limited human exposure to the soil in these areas. However, this area may have significant lead contamination because of the proximity to the dripline.

A factor that may be different from the macroclimatic evaluation of the West Town site is the sun exposure. Depending on the direction that the house is facing, sun exposure may be limited by the shadow on the house. All other factors should be relatively similar to the macroclimate evaluation.

Grubs should not pose as large of a problem in the general front yard since grubs primarily feast upon the roots of grasses. The only animal damage that may be of concern in the general front yard will be from small rodents, but this damage should be minimal. Aesthetics (GFY) Aesthetics will mainly be dependent upon the maintenance of plants in the gardens. If maintained correctly, there should be no issues with the aesthetics of the general front yards. Aesthetically pleasing plants will be assumed to be plants that flower, though some ornamental grasses and other plants may also be used.

Since the general front yard is gated and has limited access, there should be minimal problems with the durability of the plants with respect to human traffic. The only durability issue that may arise is concern with respect to proximity to the drip line along the house. The drip line will not be a concern if shrubs that are very sturdy and have strong branch networks are planted.

Though the general front yard may have some grasses, most of these areas are gardens and therefore are subjected to many of the concerns associated with gardens. The major concern of gardens is incomplete coverage of the soil. Gardens, if left unprotected, pose a serious threat of lead exposure. A barrier, such as wood chips, mulch, or topsoil, should be placed to prevent lead exposure.

Because of the close proximity to the houses, there may be some concerns with respect to the drip line. The general front yard may be subjected to heavy rain runoff that many plants may not be able to withstand. Furthermore, these areas are of great importance because often the highest lead levels in a yard are found along the drip line. Along the drip line of a house, plants must be fairly durable; the plants can not have weak stems that may be broken by the heavy water stream and must be able to withstand the elevated lead levels.
 

Backyard

The backyards of the homes in the West Town community are approximately twenty-five feet long by twenty feet wide. Some backyards are smaller if there is a garage located in the back. The backyards are fairly multipurpose; gardens, places for pets, and play areas are all uses that can be found at the various backyards in West Town.
The animal/insect damage for the backyards should be similar to the damage on the parkways, though in West Town the instances of grub damage were all found in the backyards. Therefore grub damage may be more prevelent. The concerns regarding aesthetics in the backyards are similar to the concerns with regard to grasses on the parkway. Sections of the backyards are very spotty with respect to the grass. Prevention measures will need to be taken to prohibit this from happening once new grass is planted. Also, the irregularities that occur on a lawn infested with grubs will need to be smoothed out before new grass is planted.

Again, durability issues should be similar to issues on the parkway, though there are some factors that are different. Issues such as salinity should not be as large of a concern, since there will not be roadway deposition in the backyards. Other factors should be similar. Furthermore, there should also be increased traffic from pets in these areas. Therefore, a durable grass will be needed which can withstand these pressures throughout the yards in West Town, not just on the parkways.

By moving the areas at which the pet's leash is tied up, the wear will be more distributed throughout the lawn and this will prevent exposure of bare soil. Other methods of prevention would be to set up barriers in areas where excessive wear is unavoidable. For example, sand or mulch may be placed under a swing set to prevent bare soil. Barriers may also be necessary under auto park/work areas and under garbage cans, recycling and composting bins where sunlight exposure is limited.
 

Site Characteristics:
 

Climate:

Chicago resides in a humid continental climate, and it is assumed that the general climatic conditions that exist in Chicago will correlate to the conditions in West Town. The climate data from this chart is necessary in choosing plants for the West Town site. Often conditions, such as precipitation and temperature are specified for optimal plant growth.

Compaction:

The general compaction conditions at West Town should be considered medium to heavy. Background information on the compaction at the site is important because if the conditions are not ideal for a certain plant to be placed in the soil, the conditions must be altered. Most likely the soil at West Town will need to be rototilled to loosen up the soil so that seeds may be planted.

Drainage:

The drainage at the West Town site is not quantitatively known. What is known is the distribution of various particles within the soil. This data, which was provided by A&L Great Lakes Laboratories is listed in the table below.

Based upon the soil composition data, the soil lies within several areas. The different classes found in West Town (Loam, Clay Loam, Sandy Clay Loam) are all borderline with respect to drainage properties. Sandy soils will have good drainage, while clays will have typically poor drainage. This is because sandy soils are coarser and have larger pores, while clays have finer particles and smaller pores. It can be assumed that these soils have medium coarseness, since they all fall within the "loam" classification. There are many other factors that will determine the drainage at the various sites in West Town. A landscaping specialist will have to come on site and make a proper diagnosis.

Based upon the medium-highly compacted soils and the suspected ponding on-site, drainage is estimated to range between average and poor. If the drainage is poor, grading and other drainage improvement methods will need to be implemented.

Sunlight:

The average possibility of sunlight in the Chicago area is around 54%. Most areas are going to be in partial shade, mainly because the small yards are in close proximity to the buildings. Even the parkway areas may be partially covered in shade from trees that are present. Conditions at the site will range from sunny to shady on the microclimate level.

Because of the general climatic conditions, there will not be extreme sunlight (based on the 54% average), though extreme shade may occur in the shadow of buildings and other fixtures. Even shade tolerant grasses need sunlight 65% of five hours (or approximately three hours and fifteen minutes), so intense shade may not allow for proper growing of grasses.

Soil composition:

The organic matter content is an important variable to consider because it will demonstrate the need for additional organic fertilizer to be added to the soil. Plants with a need for a highly fertile soil may need a higher organic matter percentage than what is available on-site. The amount of fertilizer also may be dependent on the cation exchange capacity (CEC). A high CEC value characterizes media with a high nutrient-holding capacity, which means it can retain nutrients for plant uptake between applications of fertilizer (Cornell University Web Site, 1999).

Lead levels were also taken at the site. This data will be useful to determine if phytoremediation is necessary at all the various locations in West Town. Based upon a standard of 400 ppm, all lead levels are in excess. Some standards for Pica Children require standards of 150 ppm. Regardless of the standard, all the sampling sites will require some form phytoremediation

Debris:

In the yards of many residences in West Town, there is exposed debris that will need to be removed from the site. The debris ranges in size from large household appliances to small bits of metal and other trash. Some small debris has been imbedded into the soil and will also need to be removed. This is especially a problem on the parkway, near the streets.
 
 

Altgeld Gardens - Playground Example

The case study site for the playground is Altgeld Gardens, a CHA community located in the southeast section of Chicago. Analysis of the playground sites at Altgeld Gardens should be simpler than study of the various residential areas at West Town because only one classification of plants will be targeted: grasses. Altgeld Gardens has the same climate as West Town.
 
 

The compaction at Altgeld Gardens is essentially the same as West Town. The soil is very hard and very compacted. J.A. Kostel of Northwestern University has stated that there is a lot of ponding on-site at Altgeld Gardens.

It will be assumed that there is poor drainage.

Sun exposure will be slightly different for the playgrounds at Altgeld Gardens than the residences at West Town. Because the playgrounds are more open and have fewer shadows from buildings and other fixtures, there will be a greater amount of sunlight reaching the plants. It is assumed that plants with no shade tolerance will be able to grow on the playgrounds of Altgeld Gardens.

Grasses on the playground sites will all need to be very durable. On the baseball field, infield sand/dirt testing will need to be done on the infield dirt to see if lead is indeed an issue. If there is lead contamination in the dirt, then it the dirt will either need to be removed and replaced, or grass will need to be planted over it. On the soccer field and other fields the same grasses as those for the outfield/infield are suggested. Any apparatus that does not have a durable covering surrounding the play area should have such a barrier installed.

Preferred barriers include rubberized playground materials, sands, and wood chips. Sand and wood chips would most likely be surrounded by a wooden curb to enclose the material, so that the coverings do not spill into other areas. 8.2.10 Jungle Gyms Coverings All jungle gyms should have a barrier covering as its base. Preferred barriers include rubberized playground materials, sands, and wood chips. Rubberized materials would be preferred because of the added cushioning for children who may trip or fall within the jungle gym. 8.2.11 Other One particular concern was paths that had been worn down to bare soil because of heavy foot and bicycle traffic. To combat these situations, permanent paths should be constructed so that there will no longer be bare soil. Concrete, stone, or some other material should be placed where the current "temporary" pathway is found.