Evaluating Strategies for Watershed Protection and Management
The world's watersheds are among the most valuable resources that we have on planet earth. Human beings cannot survive without water. Therefore, managing our watersheds is an important responsibility. Many tools are available for the management of our nation's watersheds. This research will explore two of these tools and examine cast studies to illustrate the advantages and disadvantages of their use.
Land Use Planning
Land use planning is one of the most important tools for land use management. One of the main problems faced by urban planners is uncontrolled growth and urban sprawl, both of which have negative affects on the quality of water available (Kauffman, Brant, & Kitchell). The invasion of the suburbs into natural areas means the continued development of low-density populated areas. As the city begins to spread, it has a number of impacts on the local economy. Sprawl has an impact on local agricultural income, forestry, ecological diversity, tourism and other industries that once used the space as a productive portion of the economy (Watershed Protection Techniques, 1997). In addition, it means the need for a new infrastructure to serve the new community. This taxes resources, such as the need for a sewage treatment plant, and the loss of protected watershed resources. Urban sprawl begins the process of paving the landscape and this has a major impact on the ability of the water cycle to replace the water being utilized by the new community. It is predicted that between the years of 1989-2020 stream quality in the Occuquan basin would decline to the point where they could not support the growing population (Watershed Protection Techniques, 1997).
Impervious cover thresholds have been used to protect streams and watersheds in the Christina River Basin in Delaware. This area of the country has been used by New Castle County, Delaware to protect the streams watersheds that provide nearly 75% of the drinking water for its residents. Impervious cover refers to buildings, roads, sidewalks, and other surfaces in the urban setting. These structures prevent the ability of water to filter back into the ground, maintaining The quantity and quality of water available.
The Impervious Cover Threshold method utilizes surface coverage to provide a measurable, scientifically defensible means to protect watersheds (Kauffman, Brant, & Kitchell). This method successfully provided a way to develop sound policy in the Christina River Basin, demonstrating the effectiveness of the method for urban design. Planners can provide for sufficient "green space" and can calculate the impact of building plans via roof area, on the watershed.
The Impervious Cover Threshold method focuses on developing a strategy for determining the capacity of the watershed to sustain the population. This method focuses on the ability of the watershed to sustain a certain population level. Development capacity of analysis is closely related to this technique in that it utilizes a strategy that focuses on determining if the urban area has sufficient land to accommodate the expected population growth. This strategy utilizes an inventory to determine proper growth patterns and levels that can be supported by the land. Watershed availability and capacity is a key component of this inventory (NCSGRE, 2005). .
Capacity analysis is different for every community. However, the general process is the same. Capacity analysis allows officials to determine the level of developability of the land. These categories include vacant and underutilized land, residentially zoned land, land with urban services, land without physical constraints, land available for purchase development, and ladn economically feasible to develop (NCSGRE, 2005). The general process for determining land capacity involves determining the area of land available that falls into each category and then creating an inventory by area and determining the amount and direction of development that needs to take place according to the area's particular land profile/
Both the Impervious Cover Threshold method and the capacity analysis methods utilize square footage (or acreage) available. The advantage to these methods is that they provide an easily measurable and quantifiable method for determining the effects of urbanization on the land. However, they both have a key drawback in that they do not consider the actual capacity of the available watershed. Including this information would make them more responsive to the actual ability of the watershed to maintain the current and future populations.
Better Site Design
The problem with many watershed management practices is that they only accomplish one goal. They may have unwanted effects on property values, pollutant loads, or involve high costs (Watershed Protection Technqiues, n.d.a). There is a need in watershed management practices for the development of a technique that utilizes a more balanced approach and that takes these other factors into consideration, in addition to the main problem of watershed management.
The Better Site Design technique includes to total impervious cover in its calculation. Better Site Design means minimizing the space needed for paved surfaces. For instance, it means minimizing the width of the street needed for cars, placing houses so that they take up the least total area, and other techniques to reduce the amount of impervious cover in the area.
Better Site Design techniques differ in commercial and residential areas. The types of buildings and needs of the occupants of those buildings accounts for the biggest differences in utilizing this technique in these different areas. Duck Crossing is an excellent example of utilizing green space to increase infiltration and reduce runoff. Better Site Design. Changes in septic systems, and storm water treatment made the greatest impact on increasing infiltration and reducing runoff. The Better Site Design method improved water infiltration by nearly 25% over what would have been achieved utilizing conventional development systems (Water Protection Techniques, n.d. b).
Better Site Design for commercial sites focuses on parking lot redesign so that runoff is reduced. The example of the Old Farm Shopping Mall in Frederick, Maryland is an example of a project that used this concept. Like many strip malls, nearly 50% of the area was used for parking. Only a small percentage was actually used for the building footprint, and even less for storm water treatment. The parking lot far exceeded what was needed. Parking lot runoff not only diminished he recovery capacity of the watershed, it adds tremendous amounts of pollutants to the watershed as well (Water Protection Techniques, n.d.c). Reducing the size and number of parking stalls reduced the parking area by one acre, allowing for the installation of proper storm water treatment system that removed pollutants (Water Protection Techniques, n.d. c). This project demonstrates how little changes in site design can add up to big improvements in watershed management.
These examples of Better Site Design demonstrates that little changes in land management and site design at the planning stage can mean big improvements in watershed management. In the Old Farm Shopping Mall project, it was noted that even though the new redesign of the parking lot improved water infiltration and reduced runoff, the best watershed management existed when the site was a meadow before development. This highlights the importance of green spaces in planning and design from the standpoint of preserving the watershed. Better Site Design takes a proactive approach to watershed preservation. It also demonstrates how little it takes of redesign a parking lot in order to increase the amount of water infiltration space.
The two watershed management strategies utilized in this research work best for planned communities, as these factors can be included in the initial design of the sites and buildings. Once, the buildings are in place, it is difficult to improve watershed management practices after the project is complete. Neither of these techniques can correct mistakes of the past. They focus on the planning stage of the project. They minimize future damage, but can do little to change current infiltration and runoff…