Chapters 8, 9, and 10 and prepare a synopsis (summary) of the
Contents, about 1 to 2 pages for each Chapter in Word document format.
Chapter 8: Infrastructure – Pgs. 263-298
The critical elements are that water is considered a resource rather than a problem and that interaction with the environment is carefully weighed to maximize total benefits and minimize costs. In the past storm water has been viewed primarily as a problem, to be collected and disposed of as quickly and as efficiently as possible. As our understanding of the environment and sustainability improves, we have realized that storm water is an important resource. Development and environmental protection can coexist. In light of the recognition of the environmental impacts, sites designs must use more effective and sustainable strategies. Instead of addressing storm water as a problem, designers must see it as a resource. The rational method is often used to calculate peak discharge. Even though rainfall depths are much less, arid and semiarid areas have a much greater pollutant load for each storm event and may experience substantially greater sediment loads due to the lack of stabilizing vegetation. Vegetated swales encourage infiltration, filter water by providing many surfaces for deposition, and reduce the velocity of water. The swale infiltration system increases the capacity of the typical swale to allow infiltration of low flow, frequent storm events. In cases where velocity may exceed the recommended rate, it may be necessary to reinforce the channel using geotextile fabric. Permanent fabrics designed to reinforce vegetated channels extend the designers’ choices significantly. Geotextiles should be selected on the basis of their ability to resist the flow of moving water, to protect the channel surface, and to hold the vegetation in place. The preferred method of storm water quality management is to reintroduce the runoff into the soil as quickly as possible to provide the opportunity for groundwater recharge. The dry well is designed to collect runoff directly from a roof drain or outfall. In vegetated filter strips the surfaces of the plants act as surfaces for the deposition of contaminants that might exist as films in the runoff. They remove particulates such as metals and phosphorus by filtration through the surfaces of the vegetation and promote some infiltration. The sand filter is an effective method for removing suspended solids, but it has no designed biological treatment capacity and cannot remove soluble pollutants. An infiltration trench is lined with filter fabric and filled with stone. The spaces between the stones provide the storage area for the runoff. An infiltration basin offsets the increase in runoff from the developed site. They have a large surface area to provide the maximum possible soil surface contact for the collected runoff.
Rain gardens provide an elegant opportunity for designers to incorporate the aesthetic and functional elements of a landscape into a single feature. A wet pond is an alternative to the infiltration and recharge methods. It’s an effective process for the removal of certain urban pollutants through settling in the permanent pool. Green roofs employ a relatively thin layer that acts as the root zone for the plants as well as the collection media for storm water and the means of conveying excess water from the roof.
The basic gray water system includes the collection of water from showers, sinks and washing machines. The water is filtered using a typical primary treatment methodology to remove particles. Gravity collection systems are designed to use as few pumps as possible by taking advantage of the natural lay of the land and by careful design and construction. On-site sewage disposal systems are comprised of a holding tank and a drain field. The tank provides for settlement and some digestion of the solids. Liquids rise to the surface are usually pumped to a drain field. Constructed wetlands are used as a treatment system for on-site sewage disposal systems that have physical limitations or in cases where an existing system is failing. Properly constructed and operating systems have no odor and are quite flexible in terms of design form.
Chapter 9: Landscape Restoration – Pgs. 299-348
Landscape ecology embraces the concept of the “total human ecosystem”; that is, that humans, along with all of our activities and cultural complexities, are part of the landscape. By understanding the principles of landscape integrity, the site planner can incorporate these elements into the site design. Landscapes can be described in terms of four general elements of vegetative mass and form: patches, edges, connecting corridors, and mosaic. Landscape restoration encompasses a broad range of activities and concerns, including rehabilitation, reclamation, and remediation efforts. Soil structure is the arrangement of soil particles into aggregates of mineral soil material, organic material, and microorganisms. The agglomeration of soil into aggregates is an important element of a healthy soil ecosystem, but it cannot be accomplished within the time frame allowed for revegetating a disturbed site. In most circumstances, allowances should be made for a soil analysis. Collection of the soil sample is a function of the homogeneity of the soil, the ease of collection, and the construction of the sampling equipment. Seed bed preparation generally occurs after “finish grading” is completed; however, the surfaces to be seeded are hard and smooth and not ready to be seeded by any means. Slopes should be left in a rough condition. A smooth slope is a more difficult surface on which to establish vegetation than a slope left with clods and imperfections. Plant materials selected to re-vegetate a site must be able to establish quickly in a harsh environment. Plan for the success of re-vegetation in the extremes of the environment, not only for average conditions; the droughty summer and especially harsh winter are to be expected in the plan. Although sod materials can be expensive and require additional installation efforts, sod is appropriate for certain locations and applications. Sodded areas resist erosion and quickly cover areas in the summer when cool-season grasses will not grow. Although the grasses and forbs used to stabilize a slope immediately after the disturbance may become established and even thrive, the long-term success of the stabilization can be improved by incorporating trees into the stabilization plan. The goal of the stream buffer is to re-create or maintain to the extent possible the pre-developed conditions of overland sheet flow, infiltration, and the process of filtration and deposition provided by vegetation. In general, native species of vegetation should be encouraged and invasive exotics removed. The stabilization of a stream bank requires careful consideration of the stream under various flow conditions. Stream bank vegetation provides mechanical stabilization of the bank by its roots and acts to absorb some of the energy of flooding. Wetlands play an important role in the hydrologic cycle and are very productive environments. Nutrients collect in wetlands, and wetlands generally display a great deal of biodiversity in plant and animal life. Wetlands are difficult to create because much of the hydrology associated with them is groundwater in nature. The key to the long-term success of creating a wetland is the design of the hydrologic element. Regulatory restrictions protect wetlands, but much of the damage to wetlands occurs due to changes in the contributing upland area. The practice of reusing previously developed sites has become more common in recent years due to a more favorable public policy environment. Often these sites are referred to as brownfields. Brownfields present a greater challenge to planners than sites unencumbered by contamination issues. A broad range of technologies and strategies are available for on-site treatment. Brownfield redevelopment employs all of the techniques and materials normally used in site design. Constructing a cap on a site isolates and contains contaminated material from receptors and from natural transport mechanisms. Capped sites may restrict penetrations by plant roots as well as requiring the designer to treat the site as if it were, in effect, a rooftop. Rooftop strategies adapt well to capped sites for the most part.
Chapter 10: Vegetation in the Site Plan – Pgs. 349-388
Effective planting design is a synthesis of texture, color, line, form, and balance. Elements are used in combinations to evoke a certain response or to provide a desired character to the project site. Once established, native landscapes tend to require less care, less water, and fewer inputs because the plants have evolved to survive and even flourish in the extremes of a particular region or zone. The threat from invasive exotic plants is expected to increase, and the damage to native plants will grow accordingly. When selecting plants for the landscape, designers should evaluate the impact of their choice of materials on the environment.
Energy efficiency can be improved by as much as 30 percent by properly selecting and locating plants. Buffer plantings can be designed for a variety of purposes or for a combination of purposes. To be effective, a planted buffer must be designed to accomplish the specific task or tasks required, and the selection of plant types and characteristics is a key element of the design. Whether existing or new, the fundamental need of healthy trees is evident in the physical environment. The single most common cause of city tree mortality is drainage. The next most common cause of tree losses is from mechanical damage from wire baskets, wire from staking, tree grates, or tree wrap or irresponsible construction. Trees should be chosen with an understanding of their cultural contributions to urban areas and the intended impact or value to the site. A lot with trees is viewed as more valuable and will bring a higher price on the market, and mature trees are viewed as the most desirable aspect of the residential landscape. Planning and constructing tree wells can save existing trees, but these trees should be chosen for their value and contribution to the landscape to justify the cost and effort of the tree well. It is more difficult to protect a tree from a change in grade that involves removing soil from its base. As concerns grow over the consequences of global warming, planting trees may emerge among the strategies used to offset the continuing increase in carbon dioxide in the atmosphere. Using plants to clean up site contamination has become more common as a brownfield remediation strategy. The trend toward specialized landscapes has increased in recent years along with our appreciation for the natural beauty of landscapes.